Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

The albino lemma 1 (alm1) mutants of barley (Hordeum vulgare L.) exhibit obvious chlorophyll-deficient hulls. Hulls are seed-enclosing tissues on the spike, consisting of the lemma and palea. The alm1 phenotype is also expressed in the pericarp, culm nodes and basal leaf sheaths, but leaf blades and awns are normal green. A single recessive nuclear gene controls tissue-specific alm1 phenotypic expression. Positional cloning revealed that the ALM1 gene encodes a Golden 2-like (GLK) transcription factor, HvGLK2, belonging to the GARP subfamily of Myb transcription factors. This finding was validated by genetic evidence indicating that all 10 alm1 mutants studied had a lesion in functionally important regions of HvGLK2, including the three alpha-helix domains, an AREAEAA motif and the GCT box. Transmission electron microscopy revealed that, in lemmas of the alm1.g mutant, the chloroplasts lacked thylakoid membranes, instead of stacked thylakoid grana in wild-type chloroplasts. Compared with wild type, alm1.g plants showed similar levels of leaf photosynthesis but reduced spike photosynthesis by 34%. The alm1.g mutant and the alm1.a mutant showed a reduction in 100-grain weight by 15.8% and 23.1%, respectively. As in other plants, barley has HvGLK2 and a paralog, HvGLK1. In flag leaves and awns, HvGLK2 and HvGLK1 are expressed at moderate levels, but in hulls, HvGLK1 expression was barely detectable compared with HvGLK2. Barley alm1/Hvglk2 mutants exhibit more severe phenotypes than glk2 mutants of other plant species reported to date. The severe alm1 phenotypic expression in multiple tissues indicates that HvGLK2 plays some roles that are nonredundant with HvGLK1.

DOI： 10.1093/pcp/pcab001

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To elucidate the diversity and evolution of the Si7PPO gene that controls phenol color reaction (Phr) in foxtail millet, Setaria italica, we analyzed sequence polymorphisms of the Si7PPO gene in 39 accessions consisting of foxtail millet landraces (32 accessions) and their wild ancestor ssp. viridis (seven accessions) collected from various regions in Europe and Asia. The accessions included wild type (positive Phr) and three different types of loss-of-function phenotype (negative Phr), "stop codon type", "TE1-insertion type" and "6-bp duplication type", found in our previous study. We constructed a phylogenetic tree of the gene and found that accessions with positive Phr showed higher genetic diversity at the nucleotide sequence level. We also found that the three different loss-of-function types formed different clusters, suggesting that landraces with negative Phr have multiple origins from three different lineages including both landrace and ssp. viridis accessions with positive Phr.

DOI： 10.1266/ggs.20-00011

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

Phytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds 1-3 in barley (Hordeum vulgare) roots infected by Fusarium culmorum, the causal agent of Fusarium root rot. Compounds 1-3 were identified as cinnamic acid amides of 9-hydroxy-8-oxotryptamine, 8-oxotryptamine, and (1H-indol-3-yl)methylamine, respectively, by spectroscopic analysis. Compounds 1 and 2 had been previously reported from wheat, whereas 3 was an undescribed compound. We named 1-3 as triticamides A-C, respectively, because they were isolated from barley and wheat, which belong to the Triticeae tribe. These compounds showed antimicrobial activities, indicating that triticamides function as phytoalexins in barley. The administration of deuterium-labeled N-cinnamoyl tryptamine (CinTry) to barley roots resulted in the effective incorporation of CinTry into 1 and 2, which suggested that they were synthesized through the oxidation of CinTry. Nine putative tryptamine hydroxycinnamoyl transferase (THT)-encoding genes (HvTHT1-HvTHT9) were identified by database search on the basis of homology to known THT gene sequences from rice. Since HvTHT7 and HvTHT8 had the same sequences except one base, we measured their expression levels in total by RT-qPCR. HvTHT7/8 were markedly upregulated in response to infection by F. culmorum. The HvTHT7 and HvTHT8 enzymes preferred cinnamoyl- and feruloyl-CoAs as acyl donors and tryptamine as an acyl acceptor, and (1H-indol-3-yl)methylamine was also accepted as an acyl acceptor. These findings suggested that HvTHT7/8 are responsible for the induced accumulation of triticamides in barley.

DOI： 10.3390/ijms20225541

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Changes in specialized metabolites were analyzed in wheat leaves inoculated with Bipolaris sorokiniana, the causal agent of spot blotch of Poaceae species. HPLC analysis detected the accumulation of six compounds in B. sorokiniana-infected leaves. Of these, we purified two compounds by silica gel and ODS column chromatography and preparative HPLC, and identified them as cinnamic acid amides, N-cinnamoyl-9-hydroxy-8-oxotryptamine and N-cinnamoyl-8-oxotryptamine, by spectroscopic analyses. The remaining four compounds were predicted to be p-coumaric acid amides of hydroxyputrescine, hydroxyagmatine, hydroxydehydroagmatine, and agmatine by mass spectrometry. The accumulation of two cinnamic acid amides was also induced by Fusarium graminearum infection, and by treatment with CuCl2, jasmonic acid, and isopentenyladenine. Antifungal activity of these amides was shown by inhibition of conidial germination and germ tube elongation of F. graminearum and Alternaria brassicicola, indicating that they act as phytoalexins. The accumulation of these amides also detected in barley leaves treated with CuCl2. We examined the accumulation of 25 phenylamides in B. sorokiniana-infected wheat leaves using LC-MS/MS. Hydroxycinnamic acid amides of tryptamine, serotonin, putrescine, and agmatine, were induced after infection with B. sorokiniana. Thus, the induced accumulation of two groups of phenylamides, cinnamic acid amides with indole amines, and p-coumaric acid amides with putrescine and agmatine related amines, represents a major metabolic response of wheat to pathogen infection.

DOI： 10.1016/j.phytochem.2019.112098

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE RESEARCH  

Genebanks hold comprehensive collections of cultivars, landraces and crop wild relatives of all major food crops, but their detailed characterization has so far been limited to sparse core sets. The analysis of genome-wide genotyping-by-sequencing data for almost all barley accessions of the German ex situ genebank provides insights into the global population structure of domesticated barley and points out redundancies and coverage gaps in one of the world's major genebanks. Our large sample size and dense marker data afford great power for genome-wide association scans. We detect known and novel loci underlying morphological traits differentiating barley genepools, find evidence for convergent selection for barbless awns in barley and rice and show that a major-effect resistance locus conferring resistance to bymovirus infection has been favored by traditional farmers. This study outlines future directions for genomics-assisted genebank management and the utilization of germplasm collections for linking natural variation to human selection during crop evolution.

DOI： 10.1038/s41588-018-0266-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Plants have developed defensive specialized metabolites over the course of evolution. In the genus Hordeum, which includes the important cereal crop barley, specialized metabolites such as hordatines, benzoxazinones, and gramine have been identified. Hordeum species are classified into four clades, H, Xu, Xa, and I. The presence or absence of defensive specialized metabolites was analyzed in representative Hordeum species that included all of the four clades. In the H Glade, Hordeum vulgare accumulated hordatines but not benzoxazinones, whereas H. bulbosum accumulated neither compound. Some accessions in the H Glade accumulated gramine. Species in the clades I and Xa accumulated benzoxazinones without hordatines. In H. murinum, a Xu Glade species, neither hordatines nor benzoxazinones were detected. Two hitherto undescribed compounds were found to commonly accumulate in H. bulbosum in the H Glade and H. murinum in the Xu Glade. On the basis of spectroscopic analyses, they were identified as dehydrodimers of feruloylagmatine and were designated murinamides A and B. Radical coupling reactions with feruloylagmatine as a substrate by peroxidase afforded murinamides A and B. These compounds showed antifungal activities against Bipolaris sorokiniana and Fusarium asiaticum, indicating their defensive roles. Because hordatines are also dehydrodimers of hydroxycinnamic acid amides (HCAAs) of agmatine, both the H and Xu Glade species are considered to accumulate the same class of compounds. Thus, when the H/Xu clades split from the I/Xa clades during evolution, the defensive metabolites shifted from benzoxazinones to dehydrodimers of agmatine HCAAs plus gramine in the H/Xu clades. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.phytochem.2017.05.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

The Poaceae is a large taxonomic group consisting of approximately 12,000 species and is classified into 12 subfamilies. Gramine and benzoxazinones (Bxs), which are biosynthesized from the tryptophan pathway, are well-known defensive secondary metabolites in the Poaceae. We analyzed the presence or absence of garamine and Bxs in 64 species in the Poaceae by LC-MS/MS. We found that Hordeum brachyantherum and Hakonechloa macra accumulated gramine, but the presence of gramine was limited to small groups of species. We also detected Bxs in four species in the Pooideae and six species in the Panicoideae. In particular, four species in the Paniceae tribe in Panicoideae accumulaed Bxs, indicating that this tribe is a center of the Bx distribution. Bxs were absent in the subfamilies other than Pooideae and Panicoideae. These findings provide an overview of biased distribution of gramine and Bxs in Poaceae species.

DOI： 10.1080/09168451.2016.1256758

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC BREEDING  

Barley (Hordeum vulgare L.) is the fourth most-produced cereal in the world and is mainly utilized as animal feed and malts. Recently barley attracts considerable attentions as healthy food rich in dietary fiber. However, limited knowledge is available about developmental aspects of barley leaves. In the present study, we investigated barley narrow leafed dwarf1 (nld1) mutants, which exhibit thin leaves accompanied by short stature. Detailed histological analysis revealed that leaf marginal tissues, such as sawtooth hairs and sclerenchymatous cells, were lacked in nld1, suggesting that narrowed leaf of nld1 was attributable to the defective development of the marginal regions in the leaves. The defective marginal developments were also appeared in internodes and glumes in spikelets. Map-based cloning revealed that NLD1 encodes a WUSCHEL-RELATED HOMEOBOX 3 (WOX3), an ortholog of the maize NARROW SHEATH genes. In situ hybridization showed that NLD1 transcripts were localized in the marginal edges of leaf primordia from the initiating stage. From these results, we concluded that NLD1 plays pivotal role in the increase of organ width and in the development of marginal tissues in lateral organs in barley.

DOI： 10.1270/jsbbs.16019

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER HEIDELBERG  

MYB transcription factors exist in a large copy number and control various plant phenotypes. We cloned R2R3 MYB-type transcription factors that determine the coloration of basal sheaths in barley and wheat coleoptiles. These genes are highly homologous to maize C1 and rice OsC1, regulators for anthocyanin biosynthesis, but they control seed pigmentation in maize and rice. On the basis of high homology, barley and wheat counterparts are designated HvC1 and TaC1, respectively. HvC1 gene is located on the short arm of chromosome 7H, and TaC1 genes are located on the short arms of chromosomes 7A, 7B, and 7D (TaC1-A1, B1, and D1, respectively). HvC1 is a strong candidate for Ant1 because of (1) complete co-segregation of anthocyanin pigmentation phenotype of the basal sheath with the HvC1 genotype in genetic mapping, and (2) complete deletion of the HvCl gene in two anthocyanin-decreased allelic mutants (ant1.1 and ant1.2) that were induced by irradiation. In contrast, colorless coleoptile wheat lines had lesions in all three genomes consisting of a single-nucleotide substitution or a 1-bp deletion of TaC1-A1, a 1.7-kb insertion of TaC1-B1, and a 2.0-kb insertion of TaC1-D1. At least one normal TaC1 gene appears to be sufficient to produce anthocyanin pigments in wheat coleoptiles. Previous crossing experiments localized Rc (red coleoptile) genes to homoeologous group 7 chromosomes and deduced Rc genotypes of several wheat lines. Their TaC1 gene sequence variation coincided with deduced Rc genotypes; therefore, the present molecular genetic study demonstrates that TaC1 is a strong candidate for Rc in wheat.

DOI： 10.1007/s00438-015-0991-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER HEIDELBERG  

Foxtail millet shows variation in positive phenol color reaction (Phr) and negative Phr in grains, but predominant accessions of this crop are negative reaction type, and the molecular genetic basis of the Phr reaction remains unresolved. In this article, we isolated polyphenol oxidase (PPO) gene responsible for Phr using genome sequence information and investigated molecular genetic basis of negative Phr and crop evolution of foxtail millet. First of all, we searched for PPO gene homologs in a foxtail millet genome database using a rice PPO gene as a query and successfully found three copies of the PPO gene. One of the PPO gene homologs on chromosome 7 showed the highest similarity with PPO genes expressed in hulls (grains) of other cereal species including rice, wheat, and barley and was designated as Si7PPO. Phr phenotypes and Si7PPO genotypes completely co-segregated in a segregating population. We also analyzed the genetic variation conferring negative Phr reaction. Of 480 accessions of the landraces investigated, 87 (18.1 %) showed positive Phr and 393 (81.9 %) showed negative Phr. In the 393 Phr negative accessions, three types of loss-of-function Si7PPO gene were predominant and independently found in various locations. One of them has an SNP in exon 1 resulting in a premature stop codon and was designated as stop codon type, another has an insertion of a transposon (Si7PPO-TE1) in intron 2 and was designated as TE1-insertion type, and the other has a 6-bp duplication in exon 3 resulting in the duplication of 2 amino acids and was designated as 6-bp duplication type. As a rare variant of the stop codon type, one accession additionally has an insertion of a transposon, Si7PPO-TE2, in intron 2 and was designated as "stop codon +TE2 insertion type". The geographical distribution of accessions with positive Phr and those with three major types of negative Phr was also investigated. Accessions with positive Phr were found in subtropical and tropical regions at frequencies of ca. 25-67 % and those with negative Phr were broadly found in Europe and Asia. The stop codon type was found in 285 accessions and was broadly distributed in Europe and Asia, whereas the TE-1 insertion type was found in 99 accessions from Europe and Asia but was not found in India. The 6-bp duplication type was found in only 8 accessions from Nansei Islands (Okinawa Prefecture) of Japan. We also analyzed Phr in the wild ancestor and concluded that the negative Phr type was likely to have originated after domestication of foxtail millet. It was also implied that negative Phr of foxtail millet arose by multiple independent loss of function of PPO gene through dispersal because of some advantages under some environmental conditions and human selection as in rice and barley.

DOI： 10.1007/s00438-015-1022-x

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DOI： 10.1007/s11032-015-0251-3

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DOI： 10.1139/gen-2014-0189

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

A number of anthocyanin- and proanthocyanidin-free mutants (ant mutants) in barley were induced and selected because of breeding interest to reduce proanthocyanidins, which could cause haze and degrade the quality of beer. Ant loci, known as anthocyanin or proanthocyanidin synthesis genes, are classified into Ant1 to Ant30 through allelism tests. However, only the Ant18 gene has been molecularly shown to encode dihydroflavonol 4-reductase (DFR), which is involved in both anthocyanin and proanthocyanidin synthesis. In this study, an R2R3 MYB gene of barley was isolated by PCR and named Hvmyb10 due to its similarity to Tamyb10 of wheat, which is a candidate for the R-1 gene grain color regulator. The predicted amino acid sequences of Hvmyb10 showed high similarity not only to Tamyb10 but also to TT2, the proanthocyanidin regulator of Arabidopsis. Non-synonymous nucleotide substitutions in the Hvmyb10 gene were found in all six ant28 mutants tested. Mapping showed that a polymorphism in Hvmyb10 perfectly cosegregated with the ant 28 phenotype on the distal region of the long arm of chromosome 3H. These results demonstrate that ant28 encodes Hvmyb10, the R2R3 MYB domain protein that regulates proanthocyanidin accumulation in developing grains. The reduced grain dormancy of ant28 mutants compared with those of the respective wild types indicates that Hvmyb10 is a key factor in grain dormancy in barley.

DOI： 10.1007/s10681-011-0552-5

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The awn, an apical extension from the lemma of the spikelet, plays important roles in seed dispersal, burial, and photosynthesis. Barley typically has long awns, but short-awn variants exist. The short awn 2 (lks2) gene, which produces awns about 50% shorter than normal, is a natural variant that is restricted to Eastern Asia. Positional cloning revealed that Lks2 encodes a SHI-family transcription factor. Allelism tests showed that lks2 is allelic to unbranched style 4 (ubs4) and breviaristatum-d (ari-d), for which the phenotypes are very short awn and sparse stigma hairs. The gene identity was validated by 25 mutant alleles with lesions in the Lks2 gene. Of these, 17 affected either or both conserved regions: the zinc-binding RING-finger motif and the IGGH domain. Lks2 is highly expressed in awns and pistils. Histological observations of longitudinal awn sections showed that the lks2 short-awn phenotype resulted from reduced cell number. Natural variants of lks2 were classified into three types, but all shared a single-nucleotide polymorphism (SNP) that causes a proline-to-leucine change at position 245 in the IGGH domain. All three lks2 natural variants were regarded as weak alleles because their awn and pistil phenotypes are mild compared with those of the 25 mutant alleles. Natural variants of lks2 found in the east of China and the Himalayas had considerably different sequences in the regions flanking the critical SNP, suggesting independent origins. The available results suggest that the lks2 allele might have a selective advantage in the adaptation of barley to high-precipitation areas of Eastern Asia.

DOI： 10.1093/jxb/ers182

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

(1,3;1,4)-beta-D-glucans (mixed-linkage glucans) are found in tissues of members of the Poaceae (grasses), and are particularly high in barley (Hordeum vulgare) grains. The present study describes the isolation of three independent (1,3;1,4)-beta-D-glucanless (betaglucanless; bgl) mutants of barley which completely lack (1,3;1,4)-beta-D-glucan in all the tissues tested. The bgl phenotype cosegregates with the cellulose synthase like HvCslF6 gene on chromosome arm 7HL. Each of the bgl mutants has a single nucleotide substitution in the coding region of the HvCslF6 gene resulting in a change of a highly conserved amino acid residue of the HvCslF6 protein. Microsomal membranes isolated from developing endosperm of the bgl mutants lack detectable (1,3;1,4)-beta-D-glucan synthase activity indicating that the HvCslF6 protein is inactive. This was confirmed by transient expression of the HvCslF6 cDNAs in Nicotiana benthamiana leaves. The wild-type HvCslF6 gene directed the synthesis of high levels of (1,3;1,4)-beta-D-glucans, whereas the mutant HvCslF6 proteins completely lack the ability to synthesize (1,3;1,4)-beta-D-glucans. The fine structure of the (1,3;1,4)-beta-D-glucan produced in the tobacco leaf was also very different from that found in cereals having an extremely low DP3/DP4 ratio. These results demonstrate that, among the seven CslF and one CslH genes present in the barley genome, HvCslF6 has a unique role and is the key determinant controlling the biosynthesis of (1,3;1,4)-beta-D-glucans. Natural allelic variation in the HvCslF6 gene was found predominantly within introns among 29 barley accessions studied. Genetic manipulation of the HvCslF6 gene could enable control of (1,3;1,4)-beta-D-glucans in accordance with the purposes of use.

DOI： 10.1093/jxb/err285

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DOI： 10.1270/jsbbs.61.225

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC BREEDING  

Most cereal crops have hulless grains (naked caryopses) with a free-threshing trait, whereas the majority of barley cultivars show hulled (covered) caryopses. The naked caryopsis in barley is genetically controlled by a single locus, nod. The Nud gene (the covered caryopsis allele) encodes an ethylene response factor (ERF) family transcription factor that regulates a lipid biosynthetic pathway. For functional analysis of the barley Nud gene, we produced transgenic rice expressing Nod in the developing caryopses. All transgenic lines had caryopses that were easily dehulled at maturity, indicating that the naked caryopsis phenotype remained in spite of expression of the Nod transgene. Histochemical and lipid analyses of the transgenic rice caryopses did not show increased lipid accumulation on the surface of developing caryopses, suggesting that the Nud-mediated lipid pathway may not function in rice caryopses. The predicted rice ortholog of Nod, Os06ERF was expressed specifically in the developing caryopses. However, expression of Os06ERF ceased at an earlier developmental stage than that of the native Nod gene in barley caryopses, which was also the case for expression of the Nod transgene. This raises the alternative hypothesis that the timing of Nod expression may be critical for activating the pathway for hull-caryopsis adhesion.

DOI： 10.1270/jsbbs.61.35

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Authorship：Lead author,　Corresponding author   Language：English   Publisher：JAPANESE SOC BREEDING  

The short awn 2 (lks2) and dense spike 1 (dsp1) genes are unique to East Asian barley. These two spike-related morphological genes are important because they may be involved in stable production and local adaptation. As a first step of their positional cloning, molecular mapping was conducted in 98 F-2 plants derived from a cross between Karafuto Zairai and Aizu Hadaka 3. The dsp1 gene was mapped to the proximal region of the short arm of chromosome 7H. The lks2 gene was located on the long arm of 7H and flanked by EST-based markers k04151 and k06123, with distances of 0.5 cM in the proximal side and 1.0 cM in the distal side. Both k04151 and k06123 shared homology to rice genes on chromosome 6 that were separated with the physical distance of 5.6 Mbp. In this interval, rice barley microsynteny was exploited for marker enrichment. Of 57 rice genes attempted, 15 (26.3%) yielded polymorphic EST-based markers. Breakdown of collinearity was found in the candidate region of lks2, suggesting occurrence of structural changes in the chromosome region harboring lks2 during divergence of barley and rice from a common ancestor.

DOI： 10.1270/jsbbs.61.80

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Polyphenol oxidases (PPOs) are copper-containing metalloenzymes encoded in the nucleus and transported into the plastids. Reportedly, PPOs cause time-dependent discoloration (browning) of end-products of wheat and barley, which impairs their appearance quality. For this study, two barley PPO homologues were amplified using PCR with a primer pair designed in the copper binding domains of the wheat PPO genes. The full-lengths of the respective PPO genes were cloned using a BAC library, inverse-PCR, and 3'-RACE. Linkage analysis showed that the polymorphisms in PPO1 and PPO2 co-segregated with the phenol reaction phenotype of awns. Subsequent RT-PCR experiments showed that PPO1 was expressed in hulls and awns, and that PPO2 was expressed in the caryopses. Allelic variation of PPO1 and PPO2 was analysed in 51 barley accessions with the negative phenol reaction of awns. In PPO1, amino acid substitutions of five types affecting functionally important motif(s) or C-terminal region(s) were identified in 40 of the 51 accessions tested. In PPO2, only one mutant allele with a precocious stop codon resulting from an 8 bp insertion in the first exon was found in three of the 51 accessions tested. These observations demonstrate that PPO1 is the major determinant controlling the phenol reaction of awns. Comparisons of PPO1 single mutants and the PPO1PPO2 double mutant indicate that PPO2 controls the phenol reaction in the crease on the ventral side of caryopses. An insertion of a hAT-family transposon in the promoter region of PPO2 may be responsible for different expression patterns of the duplicate PPO genes in barley.

DOI： 10.1093/jxb/erq211

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC BREEDING  

Phylogenetic relationships within the genus Hordeum were investigated based on nucleotide sequences of the thioredoxin-like (HTL) gene. We analyzed amplified genomic DNA fragments of the HTL gene from I I Hordeum species including 16 taxa (25 accessions), which cover mainly diploid accessions together with several tetraploid accessions. Phylogenetic analysis based on the HTL sequences demonstrated a clear divergence of the four basic genomes I (H. vulgare and H. bulbosum), Xa (H. marinum), Xu (H. marinum) and H (other species) in the genus. Phylogenetic clustering also led us to infer two separate clades, one containing the I and Xu, and the other containing the Xa and H genomes. In the diploid H-genome species, American species were confirmed to be closely related and divergent from Asian species. Analysis of the Xa-genome group suggested an alloploid origin of tetraploid H. marinum ssp. gussoneanum by hybridization between the diploid cytotypes of ssp. marinum and ssp. gussoneanum. Our data also supported the hypothesis that two tetraploid cytotypes of H. marinum (ssp. marinum and ssp. leporinum) have an alloploid origin, where one genome was presumably derived from the diploid cytotype ssp. glaucum and the other from an unknown Xu-genome species.

DOI： 10.1270/jsbbs.59.595

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER IRELAND LTD  

Neutral/alkaline invertase (Inv-N) catalyzes the hydrolysis of sucrose to produce glucose and fructose. Although the rice genome contains eight Inv-N-like genes, their functions in plant development are unknown. We previously described a rice mutant, srt5, which exhibits extremely stunted postembryonic root growth that is rescuable by metabolizable sugars. In the present study, we performed a functional analysis of the SRT5 gene. We showed that SRT5 encodes a putative cytosolic Inv-N that cleaves sucrose at pH 7.0 and 8.0. An SRT5-GFP fusion protein was localized to the cytosol. Sucrose levels in srt5 root cells were elevated, consistent with a crucial role for SRT5 in cytosolic sucrose cleavage at early root developmental stages. SRT5 was found to be ubiquitously expressed in various plant organs, whereas the other seven rice Inv-Ns were differentially expressed, suggesting that the functions of these latter proteins are distinct from that of SRT5. In support of this view, molecular evolutionary analysis revealed that all of the most closely related paralogs of SRT5 (OsNIN5, OsNIN6, and OsNIN7) have multiple non-conservative amino acid substitutions not found in SRT5. These results suggest that SRT5 is the key isoform of Inv-Ns required for carbon and energy supply during early root development. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.plantsci.2009.02.002

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Authorship：Last author,　Corresponding author   Language：English   Publisher：Japanese Society of Breeding  

Root hairs, projections from the epidermal cells of the roots, are contributing to water and nutrient uptake and anchorage to the soil. To better understand genetic control of root hair formation in rice, we analyzed root hairless 1 (rth1) mutant that was induced by NaN_3 treatment. SEM observation showed that in rth1 plants, root hair elongation was abolished after the formation of bulge. High-resolution mapping using 2,088 segregants revealed three predicted genes in a 38-kb candidate interval on chromosome 7. Sequences comparison of the three genes between wild-type Oochikara and rth1 detected a nucleotide substitution only in apyrase (OsAPY). This nucleotide substitution (G→A) lies in the junction between the third intron and the forth exon, and results in the splicing anomaly to the rth1 cDNA sequence. Transgenic plants with introduced OsAPY allele restored normal root hairs and plant growth, showing a complementation of rth1 phenotype. We concluded that the root hairless phenotype of rth1 is caused by a mutation of OsAPY. OsAPY appears to be an important gene for root hair elongation and plant growth in rice.

DOI： 10.1270/jsbbs.59.13

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Other Link： http://shark.lib.kagawa-u.ac.jp/kuir/metadata/3367

Language：English   Publisher：Japanese Society of Breeding  

(1-3, 1-4)-β-D-glucan contained in barley (Hordeum vulgare L.) grains is a main component of endosperm cell walls and constitutes the cell wall matrix with arabinoxylan. A monofactorial recessive mutant gene for (1-3, 1-4)-β-D-glucanless grain was found and the new gene was designated as bgl (=(1-3, 1-4)-beta-D-glucanless grain). A linkage was found between the bgl gene and the naked caryopsis (nud) gene, and it was mapped to the centromeric region of chromosome 7H. Phenotypes in bgl cosegregated with the polymorphisms in HvCslF6, a member of cellulose synthase-like HvCslF gene family, indicating that bgl was caused by a mutation in the HvCslF6 locus. In order to clarify the characteristics of (1-3, 1-4)-β-D-glucanless barley grains, a near-isogenic line (NIL) was developed by backcrossing the Japanese two-rowed cultivar 'Nishinohoshi' as a recurrent parent. The NIL with bgl completely lacked (1-3, 1-4)-β-D-glucan in both the endosperm and aleurone layer cell walls. Microscopic analysis revealed that the NIL had thin endosperm cell walls. It also showed a softer grain texture and many more broken grains during the pearling process than the recurrent parent. The soft and friable grain texture of the NIL was probably caused by the thin endosperm cell walls.

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In contrast to other cereals, typical barley cultivars have caryopses with adhering hulls at maturity, known as covered (hulled) barley. However, a few barley cultivars are a free-threshing variant called naked (hulless) barley. The covered/naked caryopsis is controlled by a single locus (nud) on chromosome arm 7HL. On the basis of positional cloning, we concluded that an ethylene response factor (ERF) family transcription factor gene controls the covered/naked caryopsis phenotype. This conclusion was validated by (i) fixation of the 17-kb deletion harboring the ERF gene among all 100 naked cultivars studied; (ii) two x-ray-induced nud alleles with a DNA lesion at a different site, each affecting the putative functional motif; and (iii) gene expression strictly localized to the testa. Available results indicate the monophyletic origin of naked barley. The Nud gene has homology to the Arabidopsis WIN1/SHN1 transcription factor gene, whose deduced function is control of a lipid biosynthesis pathway. Staining with a lipophilic dye (Sudan black B) detected a lipid layer on the pericarp epidermis only in covered barley. We infer that, in covered barley, the contact of the caryopsis surface, overlaid with lipids to the inner side of the hull, generates organ adhesion.

DOI： 10.1073/pnas.0711034105

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

To elucidate the role of silicon more clearly in biotic stress such as pests and diseases, a silicon uptake-deficient mutant lsil originating from wild-type rice (cv. Oochikara) was used. When the mutant was grown in a seedling case, silicon did not accumulate in leaves (about 50-80 mg g(-1) dry weight), regardless of the silicon amendment. In the paddy field, however, silicon increased three-fold (373 mg g(-1) dry weight) in leaves with silicon amendment, compared with those (117 mg g(-1) dry weight) with no silicon amendment. Lesion formation by Magnaporthe grisea was significantly suppressed in the leaves of the wild-type plant that had a high accumulation of silicon, but not in the leaves of the mutant that had a low silicon accumulation. Pest resistance was also observed in the leaves of the wild-type plant, but not in the mutant. These results demonstrated that silicon can protect rice plants from damage caused by biotic stresses. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.cropro.2007.08.016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press  

DOI： 10.1093/jxb/erm026

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING  

The hulled or naked caryopsis character of barley is an important agronomic trait because of the direct link to its use. A single recessive gene, nud. located on the long arm of chromosome 7H, controls the naked caryopsis character. Previously, linked amplified fragment length polymorphism (AFLP) bands from bulked segregant analysis were screened. and the nud gene was mapped in a population of 151 F, plants. In the present study, the aim was to construct a high-resolution map of the nud gene towards its positional cloning. Two AFLP bands were converted into sequence-characterized amplified region (SCAR) markers (sKT5 and sKT9), and a previously reported SCAR marker sKT3 was improved for more reliable detection of polymorphism. A total of 2380 segregants derived from five cross-combinations were analysed, and the nud gene was flanked by sKT3 and sKT9, at the 0.6-cM proximal and the 0.06-cM distal side, respectively. The SCAR markers developed in this study should be useful for marker-assisted selection in naked barley breeding employing crosses between naked and hulled accessions.

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DOI： 10.1016/j.plantsci.2005.08.005

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Language：Japanese   Publisher：The Crop Science Society of Japan  

The shoot and root characters, the bleeding rate and the photosynthetic rate in flag leaves of rice cultivar Oochikara were compared with its short-root near isogenic line IL-srt1 at the heading stage. The bleeding rate per plant in IL-srt1 was only 56% of that in Oochikara. The total root length and total root weight in IL-srt1 were 30% and 35% of those in Oochikara, respectively. On the other hand, the bleeding rate per total root length and that per total root weight in IL-srt1 were 188% and 163% of those in Oochikara, respectively, showing a significant difference between the two lines. Thus, although the root mass was larger in Oochikara than in IL-srt1, the bleeding rate per unit root mass was higher in IL-srt1 than in Oochikara. These results suggest that the physiological activities of total root in IL-srt1 were lower than that in Oochikara, due to the smaller root mass, and that IL-srt1 had higher physiological activities per unit root mass than Oochikara. There was no significant difference in photosynthetic rate between the two lines, suggesting that the short-root gene srt1 did not affect the photosynthesis.

DOI： 10.1626/jcs.75.148

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Other Link： http://agriknowledge.affrc.go.jp/RN/2010723569

Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Auxin influx carriers are involved in auxin transport and plant development. Here we show that the mutant of rice (Oryza sativa L. ssp. indica cv 1118) arm(2) is defective in the uptake of the naturally occurring auxin indole-3-butyric acid (IBA). The acropetal and basipetal transport of IBA is reduced in arm2 roots compared with wild type. In contrast, arm2 roots are normal with respect to uptake and transport of indole-3-acetic acid (IAA). Furthermore, arm2 roots are resistant to IBA but respond normally to IAA. The mutant analysis of arm2 indicates the presence of an influx carrier system for IBA in rice roots.

DOI： 10.1093/pcp/pci117

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center dot Background and Aims The genus Hordeum exists at three ploidy levels (2x, 4x and 6x) and presents excellent material for investigating the patterns of polyploid evolution in plants. Here the aim was to clarify the ancestry of American polyploid species with the I genome.
center dot Methods Chromosomal locations of 5S and 18S-25S ribosomal RNA genes were determined by fluorescence in situ hybridization (FISH). In both polyploid and diploid species, variation in 18S-25S rDNA repeated sequences was analysed by the RFLP technique.
center dot Key Results Six American tetraploid species were divided into two types that differed in the number of rDNA sites and RFLP profiles. Four hexaploid species were similar in number and location of both types of rDNA sites, but the RFLP profiles of 18S-25S rDNA revealed one species, H. arizonicum, with a different ancestry.
center dot Conclusions Five American perennial tetraploid species appear to be alloploids having the genomes of an Asian diploid H. roshevitzii and an American diploid species. The North American annual tetraploid H. depressum is probably a segmental alloploid combining the two closely related genomes of American diploid species. A hexaploid species, H. arizonicum, involves a diploid species, H. pusillum, in its ancestry; both species share the annual growth habit and are distributed in North America. Polymorphisms of rDNA sites detected by FISH and RFLP analyses provide useful information to infer the phylogenetic relationships of I-genome Hordeum species because of their highly conserved nature during polyploid evolution.

DOI： 10.1093/aob/mci147

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The phytohormone auxin is involved in the regulation of a variety of developmental. processes. In this report, we describe how the processes of lateral root and root hair formations and root gravity response in rice are controlled by auxin. We use a rice mutant aem1 (auxin efflux mutant) because the mutant is defective in these characters. The aem1 tine was originally isolated as a short lateral root mutant, but we found that the mutant has a defect in auxin efflux in roots. The acropetal and basipetal indote-3-acetic acid (IAA) transports were reduced in aem1 roots compared to wild type (WT). Furthermore, gravitropic bending as well as efflux of radioactive IAA was impaired in the mutant roots. We also propose a unique distribution of endogenous IAA in aem1 roots. An immunoassay revealed a 4-fold-endogenous IAA content in the aem1 roots compared to WT, and the application of IAA to the shoot of WT seedlings mimicked the short lateral root phenotype of aem1, suggesting that the high content of IAA in aem1 roots impaired the elongation of lateral roots. However, the high level of IAA in aeml roots contradicts the auxin requirement for root hair formation in the epidermis of mutant roots. Since the reduced development in root hairs of aeml roots was rescued by exogenous auxin, the auxin level in the epidermis is likely to be sub-optimum in aem1 roots. This discrepancy can be solved by the ideas that IAA level is higher in the stele and lower in the epidermis of aem1 roots compared to WT and that the unique distribution of IAA in aem1 roots is induced by the defect in auxin efflux. All these results suggest that AEM1 may encode a component of auxin efflux carrier in rice and that the defects in lateral roots, root hair formation and root gravity response in aem1 mutant are due to the altered auxin efflux in roots. (c) 2005 Elsevier GrnbH. All rights reserved.

DOI： 10.1016/j.jplph.2004.09.012

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Research in lateral root (LR) development mainly focuses on the role of auxin. This article reports the effect of cytokinins (kinetin and trans-zeatin) on LR formation in rice (Oryza sativa L.). Our results showed that cytokinin has an inhibitory effect on LR initiation and stimulatory effect on LR elongation. Both KIN and ZEA at a concentration of 1 mu M and above completely inhibited lateral root primordium (LRP) formation. The inhibitory effect of cytokinin on LR initiation required a continuous presence of KIN or ZEA in the growth solution. Cytokinin did not show any inhibitory effect on LR emergence from the seminal root once LRPs had been formed. The LRPs that developed in cytokinin-free solution can emerge normally in the solution containing inhibitory concentration (1 mu M) of KIN and ZEA. The KIN and ZEA treatment dramatically stimulated LR elongation at all the concentrations tested. Maximum LR elongation was observed at a concentration of 0.01 mu M KIN and 0.001 mu M ZEA. The epidermal cell length increased significantly in LRs of cytokinin treated seedlings compared to those of untreated control. This result indicates that the stimulation of LR elongation by cytokinin is due to increased cell length. Exogenously applied auxin counteracted the effect of cytokinin on LR initiation and LR elongation, suggesting that cytokinin acts on LR elongation through an auxin dependent pathway. (c) 2004 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2004.08.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS  

Chromosome 5H of Hordeum vulgare 'New Golden' (NG) carries a gene(s) that accelerates heading in a wheat background. To introduce the early heading gene(s) of NG barley into the wheat genome, we attempted to induce homoeologous recombination between wheat and NG 5H chromosomes by 5B nullisomy. A nullisomic 5B, trisomic 5A, monosomic 5H plant (2n = 42) was produced from systematic crosses between aneuploid stocks of wheat group 5 chromosomes. A total of 656 F-2 plants produced by self-fertilization were screened for recombinants by a PCR assay with 3 5H-specific amplicon markers. Twelve plants (1.8%) were selected as putative wheat-barley 5H recombinants. Five of them were inviable or sterile and the remaining 7 were fertile and subjected to the progeny test. Cytological analyses using fluorescence in situ hybridization and C-banding revealed that 6 of the 7 progeny lines are true homoeologous recombinants between the long arms of chromosomes 5D and 5H, but that the other one was not a recombinant having an aberrant barley telosome. The 6 cytologically confirmed recombinant lines included only 2 types (3 lines each), which were reciprocal products derived from exchanges at the same distal interval defined by two flanking markers. One type had a small 5HL segment translocated to the 5DL terminal, and the other type had a small terminal 5DL segment translocated to the 5HL terminal. In the latter type, the physical length of translocated barley segments slightly differed among lines. Homoeologous recombinants obtained in this study should be useful for further chromosome manipulation to introgress a small interstitial 5HL chromosome segment with the early heading gene(s) to wheat. Preferential occurrence of restricted types of recombinants is discussed in relation to homoeologous relationships between wheat and barley chromosomes.

DOI： 10.1139/G04-096

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Language：Japanese   Publisher：Japanese Society of Breeding  

Although plant roots are one of the most important organs for crop cultivation, root studies lag behind due to various difficulties. The objective of the present study was to isolate genes related to root morphology using 'mutant panel', rice retrotransposon Tos17-insertion mutant lines. First, we grew 5,568 R₁ lines regenerated from tissue culture of Oryza sativa L. cv. Nipponbare in water culture, and screened the lines which segregated root mutants at the seedling stage. Then, 56 root mutant lines that were confirmed by the progeny test, were analyzed by genomic Southern hybridization using Tos17 as a probe. As a result of linkage analysis, we obtained one Tos17-tagged mutant line, NC6949. The phenotype of this mutant line was as follows: dwarf, narrow leaves and reduced numbers of crown roots and lateral roots. In this line, Tos17 was inserted in the third exon of the putative alliinase gene on the short arm of chromosome 1 and the presence of this insertion cosegregated with the mutant phenotype. We designated the gene tagged by Tos17, as OsAll1 (Oryza sativa alliinase 1). In a complementary experiment in which a 6kb genomic fragment containing alliinase/ORFs and its putative promoter region was introduced into the osall1 mutant, the root morphology in the transgenic plant was rescued. Based on these observations, it was concluded that the abnormal root morphology of the osall1 mutant obtained in this study was caused by knock out of the OsAll1 gene. In the rice genome, at least 3 other alliinase-like gene sequences are present and form a multigene family, but their expression patterns were different, suggesting that OsAll1 was functionally differentiated from the others.<br>

DOI： 10.1270/jsbbr.07.171

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Language：Japanese   Publisher：Japanese Society for Root Research  

The growth and morphology of IL-srt1, a short-root near isogenic line derived from rice cultivar Oochikara, were characterized by paddy field and pot experiments, with particular focus on the interrelationship between shoot and root growth. The shoot dry weight, stem number, root length and root dry weight per hill of IL-srt1 were lower than those of Oochikara, but the number of crown roots per hill was the same for two cultivars (line). The root weight/root length ratio of IL-srt1 was higher than that of Oochikara, which was attributed to the difference of the mean root diameter, not to the specific gravity of roots. Root system surveys by monolith method revealed that IL-srt1 had smaller root length density at everywhere in soil, and narrow rooting zone. The number of stem per hill was responsible for the difference of shoot dry weight per hill, and there was no difference in shoot dry weight per stem. It was assumed that larger number of crown roots and higher percentage of young crown roots of IL-srt1 as compared to Oochikara might compensate for shorter root length per stem, and attained the same water and nutrient supply per stem. It was also assumed that the rooting zone would closely relate to the emergence and survival of tillers through the ability of water and nutrient supply.

DOI： 10.3117/rootres.14.157

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Language：English   Publisher：OXFORD UNIV PRESS  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI IRELAND LTD  

We previously reported a mutant, srt5, in which the short-root phenotype at the seedling stage could be partially rescued by exogenous abscisic acid (ABA) [Plant Sci. 163 (2002) 217]. In this paper, we describe that exogenously applied sucrose (Suc), glucose (Glu) or fructose (Fru), but not mannitol (Mtl) or glucose analogs, can also rescue root growth of the mutant to extents greater than ABA. Combined treatment reveals that root growth of the mutant under 1 muM ABA treatment can be further promoted by the addition of sugars. In contrast, application of ABA shows no promotive effects on 100 mM sugar-treated roots of srt5 seedlings. We also observed that endogenous sucrose contents in seeds and seedlings of srt5 are significantly lower, and starch breakdown in endosperm of srt5 is normal compared to wild-type. Furthermore, when treated with ABA, sucrose content in roots increases greatly in srt5, but decreases significantly in the wild-type. Collectively, these results suggest that energy deficiency is the cause of the srt5 phenotype, and ABA regulates root elongation of the mutant in a sugar-mediated way. The possible mechanism for ABA to promote root growth by enhancing the level of sugar in roots of srt5 is discussed. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.plantsci.2004.02.025

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

The plant hormone auxin has been shown to be involved in lateral root development and application of auxins, indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA), increases the number of lateral roots in several plants. We found that the effects of two auxins on lateral root development in the indica rice (Oryza sativa L. cv. IR8) were totally different from each other depending on the application method. When the roots were incubated with an auxin solution, IAA inhibited lateral root development, while IBA was stimulatory. In contrast, when auxin was applied to the shoot, IAA promoted lateral root formation, while IBA did not. The transport of [H-3]IAA from shoot to root occurred efficiently (% transported compared to supplied) but that of [H-3]IBA did not, which is consistent with the stimulatory effect of IAA on lateral root production when applied to the shoot. The auxin action of IBA has been suggested to be due to its conversion to IAA. However, in rice IAA competitively inhibited the stimulatory effect of IBA on lateral root formation when they were applied to the incubation solution, suggesting that the stimulatory effect of IBA on lateral root development is not through its conversion to IAA.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG  

To elucidate the origin of naked barley, molecular variation of the marker sKT7 tightly linked to the nud locus was examined. A total of 259 (53 wild, 106 hulled domesticated, and 100 naked domesticated) barley accessions were studied. Restriction analysis of the sKT7 PCR-amplified product revealed the alleles I, II, III, and IV. All four alleles were found in wild barley, but allele IV was found only in a single accession from southwestern Iran. Hulled domesticated accessions showed alleles I, II, or III, but all naked domesticated accessions had allele IV. The distribution of allele IV in wild barley and its pervasive presence in naked domesticated lines support the conclusion that naked barley has a monophyletic origin, probably in southwestern Iran. The available results suggest two scenarios for the origin of naked barley: either directly from a wild barley with allele IV or from a hulled domesticated line with allele IV that later became extinct. Naked domesticated accessions from different regions of the world have extremely homogeneous DNA sequences at the sKT7 locus, supporting the monophyletic origin of naked barley. For allele IV, four haplotypes (IVb to IVe) were found in 30 naked accessions: IVb was predominant (66.7%) and widely distributed, while the other three haplotypes, differing by only one nucleotide at different positions relative to IVb, showed a localized distribution. The geographical distribution of the haplotypes of sKT7 allele IV suggests migration routes of naked domesticated barley in central and eastern Asia.

DOI： 10.1007/s00122-003-1560-1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Since root elongation is very sensitive to auxin, screening for reduced inhibition in root elongation has been an important method for the detection of auxin-resistant mutants. Two recessive auxin-resistant lines of rice (Oryza sativa L. ssp. indica cv. IR8), arm1 and arm2, have been isolated by screening for resistance to 2,4-dichlorophenoxyacetic acid (2,4-D). arm1 displays a variety of morphological defects including reduced lateral root formation, increased seminal root elongation, reduced root diameter, and impaired xylem development in roots, while the arm2 phenotype is almost similar to wild-type IR8 except for a slightly reduced lateral root formation, impaired xylem development in roots and an enhanced plant height. Although the growth of arm2 roots exhibited a resistance to 2,4-D, it was sensitive to 1-naphthaleneacetic acid (NAA) as the wild type. At the same time, the arm2 roots showed a reduced [C-14]2,4-D uptake while uptake of [H-3]NAA was normal, suggesting that the resistance to 2,4-D of arm2 roots is due to a defect in 2,4-D uptake. To investigate the possible interaction between arm1 and arm2 genes, a double mutant has been constructed. The roots of arm1 arm2 double mutant were more resistant to 2,4-D and formed fewer lateral roots than those of either single mutant, suggesting that the two genes show synergistic effects with respect to both auxin response and lateral root formation. By contrast, all these mutants displayed the normal gravitropic response in roots, as did the wild-type plants. Taken together, Arm1 and Arm2 genes seem to function in different processes in the auxin-response pathways leading to lateral root formation.

DOI： 10.1093/jxb/erg306

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG  

The hulled or naked caryopsis character of barley (Hordeum vulgare L.) is an important trait for edibility and to follow its domestication process. A single recessive gene, nud, controls the naked caryopsis character, and is located on the long arm of chromosome 7H. To develop a fine map around the nud locus efficiently, the HEGS (High Efficiency Genome Scanning) electrophoresis system was combined with amplified fragment length polymorphism (AFLP). From bulked segregant analysis of 1,894 primer combinations, 12 AFLP fragments were selected as linked markers. For mapping, an F-2 population of 151 individuals derived from a cross between Kobinkatagi (naked type) and Triumph (hulled type) was used. Seven AFLP markers were localized near the nud region. A fine map was developed with one-order higher resolution than before, along with the seven anchor markers. Among the seven linked AFLP markers (KT1-7), KT1, KT2 and KT6 were co-dominant, and the former two were detected for their single-nucleotide polymorphisms (SNPs) in the same length of fragments after electrophoresis with the non-denaturing gels of HEGS. The nud locus has co-segregated with KT3 and KT7, and was flanked by KT2 and KT4, at the 0.3-cM proximal and the 1.2-cM distal side, respectively. Four of these AFLP markers were converted into sequence-characterized amplified region (SCAR) markers, one of which was a dominant marker co-segregating with the nud gene.

DOI： 10.1007/s00122-003-1413-y

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

Comparative effects of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on lateral root (LR) formation were studied using 2-day-old seedlings of IR8 rice (Oryza sativa L.). Results showed that IBA at all concentrations (0.8 - 500 nmol/L) increased the number of LRs in the seminal root. However exogenous IAA, failed to increase the number of LRs. On the other hand, both IBA and IAA caused inhibition of seminal root elongation and promotion of LR elongation, but IAA can only reach to the same degree of that of IBA at a more than 20-fold concentration. Exogenous IBA had no effect on endogenous IAA content. We conclude from the results that IBA could act directly as a distinct auxin, promoting LR formation in rice, and that the signal transduction pathway for IBA is at least partially different from that for IAA.

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This paper reports morphological and physiological characteristics of a first root-hairless mutant (RH2) of rice ( Oryza sativa L.), which can be useful in advancing knowledge on the role of root hairs in water and nutrient uptake, and genetics of root hairs. The mutant was selected among NaN3 mutagenized progeny of the rice cultivar Oochikara. Microscopic observations showed absence of root hairs in RH2. At the seedling stage, RH2 showed shorter seedling height and shorter roots compared to the wild type variety Oochikara. Because of the differences in seedling growth, all comparisons between Oochikara and RH2 in uptake-related characters were made on the basis of values adjusted by the dry weight of either the shoot or the root. When grown at low water potential in soil, Oochikara and RH2 were similar in shoot water content and transpiration per unit shoot dry weight, and similarly, at low water potential in solution culture, there was no significant difference between Oochikara and RH2 in transpiration per unit shoot dry weight. These results suggest that at the seedling stage, root hairs do not significantly contribute to uptake of water. In solution culture, Oochikara and RH2 did not significantly differ in phosphate uptake per unit root dry weight. This result supports the previous work that root hairs do not contribute to phosphate uptake in solution culture. Regarding to response to plant hormones, RH2 showed a higher level of resistance to two synthetic auxins, 2,4-dichlorophenoxyacetic acid ( 2,4-D) and 1-naphthaleneacetic acid (NAA) than Oochikara. NAA treatment induced very short root hairs in RH2, suggesting that the absence of root hairs in RH2 may be due to a shortage of endogenous auxin. Genetic analysis showed that the root hairless character in RH2 is inherited as a single recessive gene.

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The isolation and detailed characterization of a monogenic recessive root growth mutant, srt6, which was derived from an M, population of rice (Oryza sativa L.) cv. Oochikara treated with NaN3, is described. Besides greatly reduced primary root length and diameter. the mutant at the seedling stage also shows inhibited lateral root elongation and altered root hair formation. Hydroponic cultivation reveals that root length of the mutant recovers to the level of the wild type at the booting stage, but both lateral root elongation and root hair formation in the mutant remain inhibited at all growth stages. These observations suggest that the expression of the srt6 gene is phase-specific, and that the effects of SRT6 on root growth are restricted specifically to the development of primary roots. Physiological characterization reveals that the mutant has pleiotropic defects in abscisic acid (ABA) responses. which are similar to those reported for Arabidopsis ABA-insensitive mutants abi1 and abi2, i.e. reduced sensitivity of root growth and seed germination, and excessive water loss. Combined with its normal response of root growth to fluridone, the ABA biosynthesis inhibitor, suggesting that the action of the srt6 gene might be related to ABA perception or signal transduction but not ABA biosynthesis in the controlling of early primary root elongation in rice. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0168-9452(03)00081-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

Auxins control growth and development in plants, including lateral root initiation and root gravity response. However, how endogenous auxin regulates these processes is poorly understood. In this study, the effects of auxins on lateral root initiation and root gravity response in rice were investigated using a lateral rootless mutant Lrt1, which fails to form lateral roots and shows a reduced root gravity response. Exogenous application of IBA to the Lrt1 mutant restored both lateral root initiation and root gravitropism. However, application of IAA, a major form of natural auxin, restored only root gravitropic response but not lateral root initiation. These results suggest that IBA is more effective than IAA in lateral root formation and that IBA also plays an important role in root gravitropic response in rice. The application of NAA restored lateral root initiation, but did not completely restore root gravitropism. Root elongation assays of Lrt1 displayed resistance to 2,4-D, NAA, IBA, and IAA. This result suggests that the reduced sensitivity to exogenous auxins may be due to the altered auxin activity in the root, thereby affecting root morphology in Lrt1.

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Total DNA from WA type CMS lines: Zhenshan 97 A, Longtepu A and their maintainers Zhenshan 97 B, Longtepu B was extracted by CTAB method. One hundred primers were used for screening RAPD markers to distinguish CMS line (A) and maintainer (B) plants at seedling stage. Results showed that under the conditions of 37 C annealing temperature and 1.5 mM MgCl2 concentration, in Zhenshan 97 A, Longtepu A there was a 1600 bp DNA fragment in product amplified by primer OPA12, while in Zhenshan 97 B, and Longtepu B no 1600 bp fragment was found. The 1600 bp fragment was also found in DA type CMS line Xieqingzao A, but was absent in Xieqingzao B. Also in the restorer line, Minghui 63 the 1600 bp fragment was absent. In F-1 and F-2 generation of Zhenshan 97A/Minghui 63, all plants investigated had the 1600 bp fragment. When mitochondrial DNA (mtDNA) was isolated from the three CMS (A) and their B lines and amplified by OPA12, results showed that the 1600 fragment was found in all the three A lines and was absent in the three B lines. In DA type Xieqingzao A, two other fragments (700 bp, 1000 bp) were also found except the 1600 bp. These results indicate that the 1600 bp fragment derived from CMS mitochondrial DNA can be used as a RAPD marker to distinguish A and B plants at seedling stage, and the fragments (700 bp, 1000 bp) can be used to distinguish WA and DA cytoplasms.

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DOI： 10.1016/S0168-9452(03)00293-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：URBAN & FISCHER VERLAG  

The effect of JA on lateral root (LR) formation was tested using 2-day-old seedlings of IR8 rice (Oryza sativa L.). Results showed that JA in all concentrations (0.016-50 mumol/L) increased the number of LRs in the region of seminal root formed during and after the treatment (distal region), but had no effect (less than 2 mumol/L) or decreased (over 2 mumol/L) the number of LRs in the region already formed before treatment (basal region). On the other hand, the development of root hair in the distal region was inhibited, and even fully blocked by JA over 1 mumol/L. Both JA's effects on promoting LR formation and inhibiting root hair formation in the distal region could last at least 7 days subsequent to the removal of JA treatment. All these results indicated that JA might be one of the potent hormonal factors, other than auxin, involved in the regulation of LR formation.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL RESEARCH COUNCIL CANADA  

Addition of the long arm of barley chromosome 1H (1HL) to wheat causes severe meiotic abnormalities and complete sterility of the plants. To map the barley gene responsible for the 1H-induced sterility of wheat, a series of addition lines of translocated 1H chromosomes were developed from the crosses between the wheat 'Shinchunaga' and five reciprocal translocation lines derived from the barley line St.13559. Examination of the seed fertility of the addition lines revealed that the sterility gene is located in the interstitial 25% region of the 1HL arm. The genetic location of the sterility gene was also estimated by physically mapping sequence-tagged site (STS) markers and simple-sequence repeat (SSR) markers with known map locations. The sterility gene is designated Shw ((s) under bar terility in (h) under bar ybrids with (w) under bar heat). Comparison of the present physical map of 1HL with two previously published genetic maps revealed a paucity of markers in the proximal 30% region and non-random distribution of SSR markers. Two inconsistencies in marker order were found between the present physical map and the consensus genetic map of group 1 chromosomes of Triticeae. On the basis of the effects on meiosis and chromosomal location, the relationship of the present sterility gene with other fertility-related genes of Triticeae is discussed.

DOI： 10.1139/G02-024

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI IRELAND LTD  

We have isolated a novel short-root mutant, srt5, from an M-2 population of rice (Oryza sativa L. cv. Oochikara) treated with NaN3, and mapped its causal gene to chromosome 2. The mutant showed extreme inhibition of seminal root, crown root and lateral root elongation, and altered root hair formation at the seedling stage. Histological observation of seminal root tips indicated that the short-root phenotype was due to the reduced cell size and cell number. At later stages of plant development, roots of the mutant elongated acceleratingly and recovered normal morphology 45 days after transplantation, and adult plants of the mutant resembled the wild type except for reduced pollen and seed fertilities. Seminal root growth of the mutant was partially rescued by exogenously applied ABA, suggesting that ABA biosynthesis might be affected in srt5 plants. Moreover, the mutant also showed high resistance to 2,4-D, GA; and KIN based on seminal root growth assays, but the resistance to these hormones disappeared when ABA was concomitantly applied. Thus, the wild type allele of srt5 seems to be of great importance for early root development by altering plant hormone homeostasis, in which ABA plays a critical role. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SCIENCE CHINA PRESS  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG  

The origin of six-rowed cultivated barley was studied using a DNA marker cMWG699 closely linked to the vrs1 locus. Restriction patterns of the PCR-amplified product of the cMWG699 locus were examined in 280 cultivated (Hordeum vulgare ssp. vulgare) and 183 wild (H. vulgare ssp. spontaneum) barleys. Nucleotide sequences of the PCR products were also examined in selected accessions. Six-rowed cultivated barleys were divided into two distinct groups, types I and II. Type I six-rowed cultivated barley was distributed widely while type II six-rowed cultivated barley was found only in the Mediterranean region. The type I sequence was also found in a wild barley accession from Turkmenistan whereas the type II sequence was also found in a two-rowed cultivated barley from North Africa and a wild barley from Morocco. These results suggested that the six-rowed type I and II barleys were derived from two-rowed type I and II barleys, respectively, by independent mutations at the vrs1 locus.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL MUNKSGAARD  

Wheat (Triticum aestivum L.)-barley (Hordeum vulgare L.) chromosome addition lines are possible vehicles for transferring barley genes into wheat. The barley 5H chromosome has genetic effects on the heading characters in wheat-barley addition lines: accelerating narrow-sense earliness, decreasing vernalization requirement and/or increasing photoperiodic, sensitivity. To elucidate the effects of different 5H chromosomes under an identical wheat genetic background, two wheat-barley addition lines, i.e. cultivated barley 'New Golden' 5H chromosome added to 'Shinchunaga' wheat (Shi-NG5H) and wild barely H. vulgare ssp. spontaneum 5H chromosome added to 'Shinchunaga' wheat (Shi-Spn5H), were examined for their heading characters. The addition line Shi-NG5H showed a significantly lower vernalization requirement in comparison with 'Shinchunaga' wheat, whereas Shi-Spn5H did not. Furthermore, both NG5H and Spn5H chromosomes shortened narrow-sense earliness and increased photoperiodic sensitivity in wheat, but the effects of Spn5H were weaker than those of NG5H. The fact that NG5H and Spn5H showed differential effects on heading characters in wheat demonstrated that the heading characters were altered by the function of the barley genes located on 5H chromosomes, not merely by the aneuploid effect alone.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

The inheritance of the leaf pubescence character of a Chinese local wheat cultivar `Hon-mang-mai' was investigated by monosomic and telosomic analyses. Leaf pubescence was evaluated by observation of the adaxial side of the penultimate leaf of adult plants. F-1 hybrids of `Hong-mang-mai' with a non-pubescent cultivar `Chinese Spring' had leaf pubescence, but its density was about a half of that of `Hong-mang-mai'. In the F-2 generation, the segregation ratio of pubescent to non-pubescent plants fitted a ratio of 3: 1, suggesting that leaf pubescence was controlled by one dominant gene. Monosomic analysis revealed that the gene for pubescence is located on chromosome 7B. Telosomic analysis showed that the gene is located on the short arm of chromosome 7B with a distance of 14.3% from the centromere. This gene is not allelic with the previously reported hairy leaf gene Hl on chromosome 4B, and therefore, is designated Hl2, hairy leaf 2.

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DOI： 10.1023/A:1014948712848

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC BREEDING  

A wild barley, Hordeum vulgare L. ssp. spontaneum (C. Koch.) Thell. (syn. H. spontaneum C. Koch.) is considered to be the progenitor of cultivated barley (H. vulgare L. ssp. vulgare). A complete set of Triticum aestivum L. cv. 'Shinchunaga'-H. spontaneum OUH602 whole chromosome addition lines, and 5 telosomic addition lines were developed. Chromosome constitutions of the addition lines were confirmed by C-banding and genomic in situ hybridization. Addition lines for the entire IR chromosome and its long arm are only available as monosomic and monotelosomic additions, respectively, because of sterility. All other lines were recovered as disomic or ditelosomic additions. Self-sterile monosomic III and monotelosomic 1HL addition lines can be reproduced by backcrossing the plants having simultaneous addition of the long arm of barley chromosome 6H, because the plants with such chromosome constitutions recover partial female fertility. In general, the phenotypic alternations observed in each of the wheat-H. spontaneum OUH602 addition lines were similar to those previously noted in the corresponding lines of the 'Chinese Spring' wheat-'Betzes' barley addition series and the primary trisomic series of the H. spontaneum accession OUH602. Monotelosomic 1HL addition and ditelosomic IHS addition are especially valuable for unequivocal chromosome arm localization of barley genes and markers clustered around the centromeric region of 1H. The utility of the wheat-H. spontaneum addition lines is discussed.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

The physical locations of 5S and 18S-25S rDNA sequences in 15 diploid Hordeum species with the I genome were examined by double-target in situ hybridization with pTa71 (18S-25S rDNA) and pTa794 (5S rDNA) clones as probes. All the three Asian species had a species-specific rDNA pattern. In 12 American species studied, eight different rDNA types were found. The type reported previously in H. chilense (the 'chilense' type) was observed in eight American species. The chilense type had double 5S rDNA sites-two sites on one chromosome arm separated by a short distance-and two pairs of major 18S-25S rDNA sites on two pairs of satellite chromosomes. The other seven types found in American species were similar to the chilense type and could be derived from the chilense type through deletion. reduction or addition of a rDNA site. Intraspecific polymorphisms were observed in three American species. The overall similarity in rDNA patterns among American species indicates the close relationships between North and South American species and their derivation from a single ancestral source. The differences in the distribution patterns of 5S and 18S-25S rDNA between Asian and American species suggest differentiation between the I genomes of Asian and American species. The 5S and 18S-25S rDNA sites are useful chromosome markers for delimiting Asian species, but have limited value as a taxonomic character in American species. On the basis of rDNA patterns. karyotype evolution and phylogeny of the I-genome diploid species are discussed.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL WISSENSCHAFTS-VERLAG GMBH  

The adaptability of wheat cultivars to environmental conditions is known to be associated with a vernalization requirement, that is, spring/winter habit. To clarify the genetic effect of the spring habit gene, Vrn-D1, on heading time in the field, recombinant inbred lines (RILs) with or without the Vrn-D1 gene were produced from F-2 plants of the cross between 'Nanbukomugi' and 'Nishikazekomugi', non-carrier and carrier cultivars of this gene, respectively. Using growth chambers with a controlled temperature and photoperiod, three components of heading time, i.e, vernalization requirement, photoperiodic sensitivity and narrow-sense earliness (earliness per se), were evaluated in each RIL. RILs with the Vrn-D1 gene (E lines) showed greatly reduced vernalization requirements and slightly shorter narrow-sense earliness than RILs without Vrn-D1 (L lines), although no difference in photoperiodic sensitivity was observed between the two groups. RILs were planted at four different sites in Japan and examined for their heading time in the field. E lines headed significantly earlier than L lines at all locations, indicating that the earliness of E lines is stable in various environmental conditions. These results indicated that spring habit caused by Vrn-D1 gene, as well as narrow-sense earliness, was responsible for heading time in the field.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG  

Molybdenum cofactor (Moco) is essential for nitrate reductase (NR), xanthine dehydrogenase (XDH), and aldehyde oxidase to perform their catalytic functions in plants. Moco biosynthesis is a complex process involving many genes. Little is known about the genetics and molecular aspects of Moco biosynthesis in plants and other eukaryotes. In rice, we previously isolated a Moco mutant C25 with a mutation in the CNX2 gene from a mutagenized indica cultivar IR30 and characterized its biochemical properties. This mutant was crossed with a japonica cultivar, Norin 8, to investigate the linkage of cnx2 to restriction fragment length polymorphism (RFLP) and cleaved amplified polymorphic sequence (CAPS) markers. Chlorate resistance was used to trace the cnx2 mutation because of its cosegregation with the loss of NR and XDH activities observed earlier. RFLP and CAPS analyses show the location of the cnx2 locus on the long arm of chromosome 4. It is mapped between RFLP markers C513 and C377 with a distance of 9.5 and 13.1 cM, respectively. It is also linked with CAPS marker RA0738 at a distance of 30.3 cM.

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DOI： 10.1007/s001220051670

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Analysis of structural chromosomal polymorphism revealed the presence of a previously reported 2A.4B translocation common to all 15 strains of Ethiopian tetraploid wheat examined. Using the C-banding technique, we found two new translocations, T1B.6B and T5B.6B, and a pericentric inversion of chromosome 5A. The C-banding pattern indicated that in all three translocations the breakpoint was located in the centromeric region. Sequential N-banding and genomic in situ hybridization (GISH) confirmed the location of the breakpoint of translocation 2A.4B, and revealed that the breakpoint of another known translocation, 2A-2B, was in the proximal region of 2BL. The fixation of the 2A.4B translocation indicates the monophyletic origin of Ethiopian tetraploid wheat and the presence of a very severe bottleneck effect during its dispersal.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GENETICS SOC JAPAN  

Barley (Hordeum vulgare L.) is potentially a new source of genes for wheat (Triticum aestivum L.) improvement. Wheat-barley chromosome recombinant lines provide a means for introgressing barley genes to wheat genome by chromosome engineering, and since these are expected to occur only rarely in special cytogenetic stocks, an efficient selection skill is necessary to identify them. To convert RFLP markers to barley allele-specific PCR markers useful for effective production of wheat-barley recombinant lines, 91 primer sets derived from RFLP clones which were previously mapped to the barley chromosomes were examined for PCR amplification using 'Chinese Spring' wheat, 'Betzes' barley and the wheat-barley chromosome addition lines. The polymorphisms were detected by an agarose gel electrophoresis of the PCR products without digestion with restriction enzymes. Out of 81 primer sets producing polymorphisms between the wheat and barley genomes, 26 amplified barley chromosome-specific DNAs which were confirmed to be located on the same chromosome as the RFLP markers by using the wheat-barley chromosome addition lines. These amplified DNAs represent barley allele-specific amplicons, which distinguish barley alleles from their wheat homoeologous counterparts. The present investigation revealed a higher probability for obtaining allele-specific amplicons from genomic DNA-derived RFLP markers than from cDNA-derived ones. The barley allele-specific amplicons developed in this study, namely, four for chromosome 2H, two for 3H, seven for 4H, eight for 5H, one for 6H and four for 7H, are suitable for identifying 'Chinese Spring' wheat- 'Betzes' barley recombinant chromosomes. However, one out of eight barley allele-specific amplicons on chromosome 5H did not detect a unique barley band in a 'New Golden' barley chromosome 5H addition line of 'Shinchunaga' wheat, indicating there may be a need to reconstruct allele-specific amplicons with different barley cultivars.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER VERLAG  

The genomic organization and chromosomal distributions of two abundant tandemly repeated DNA sequences, dpTa1 and pSc119.2, were examined in six wild Hordeum taxa, representing the four basic genomes of the genus, by Southern and fluorescence in situ hybridization. The dpTa1 probe hybridized to between 30 and 60 sites on the chromosomes of all five diploid species studied, but hybridization patterns differed among the species. Hybridization of the pSc119.2 sequence to the chromosomes and Southern blots of digested DNA detected signals in Hordeum bulbosum, Hordeum chilense, Hordeum marinum and Hordeum murinum 4x, but not in Hordeum murinum 2x and Hordeum vulgare ssp. spontaneum. A maximum of one pSc119.2 signal was observed in the terminal or subterminal region of each chromosome arm in the species carrying this sequence. The species carrying the same I-genome differed in the presence (Hordeum bulbosum) or absence (Hordeum spontaneum) of pSc119.2. The presence of pSc119.2 in the tetraploid cytotype of Hordeum murinum, but its absence in the diploid cytotype, suggests that the tetraploid is not likely to be a simple autotetraploid of the diploid. Data about the inter- and intra-specific variation of the two independent repetitive DNA sequences give information about both the interrelationships of the species and the evolution of the repetitive sequences.

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Triticale, a hybrid between wheat and rye, shows a high degree of Al tolerance that is inherited from rye, but the mechanisms of high Al tolerance in both rye and triticale are unknown. We found that the short arm of chromosome 3R carries genes necessary for Al tolerance in triticale (x Triticosecale Wittmark cv Currency). Detailed comparative studies with a 3DS.3RL translocation line (ST22) and a non-substitution line (ST2) were conducted. Root elongation was similarly inhibited by Al in ST2 and ST22 during the first 12 h of Al treatment, but more strongly in ST22 than in ST2 at 18 h and thereafter. The root inhibition induced by other metals (Cu, Cd, and La) was similar between ST2 and ST22, suggesting that the action of the genes for Al tolerance on the short arm of triticale chromosome 3R is highly specific to Al. A 2-fold larger amount of malate and citrate was released from the roots of ST2 than from ST22 at 12 and 18 h after Al treatment, respectively. The marked lag phase in the inhibition of root elongation and the release of organic acids implies that the expression of genes on the short arm of triticale chromosome 3R is induced by Al, and that these genes are necessary for the release of organic acids.

DOI： 10.1104/pp.122.3.687

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To examine variation in phytosiderophore biosynthesis in Triticeae, phytosiderophores were investigated in wild and cultivated species of wheat and barley with different genomes. All wheats tested including hexaploid (AABBDD), tetraploid (AABB), and diploid (AA or DD) lines produced only one phytosiderophore, 2'-deoxymugineic acid. The phytosiderophores biosynthesized in wild barleys varied among species. Using substitution-type triticale lines and wheat-barley addition lines, it was revealed that, in triticale, genes for the biosynthesis of both mugineic and hydroxymugineic acids were located in the long arm of chromosome 5R and that, in barley, the gene for production of mugineic acid was located in the long arm of chromosome 4H.

DOI： 10.1093/jexbot/50.334.723

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Phytosiderophores, mugineic acids, have been demonstrated to be involved in Fe acquisition in gramineous plants. In this study, chromosomal arm locations of genes encoding for biosynthesis of various phytosiderophores were identified in a cultivar of barley (Hordeum vulgare L. cv. Betzes). Using wheat (Triticum aestivum L. cv. Chinese Spring)-barley (cv. Betzes) ditelosomic addition lines for 4HS and 4HL, a gene for hydroxylation of 2'-deoxymugineic acid to mugineic acid was localized to the long arm of barley chromosome 4H. To locate the gene for hydroxylation of mugineic acid to 3-epihydroxymugineic acid, hybrids between the 4H addition line and other wheat-barley addition lines were studied. Only a hybrid between 4H and 7H addition lines produced 3-epihydroxymugineic acid. The gene was further localized to the long arm of chromosome 7H by feeding mugineic acid to ditelosomic addition lines for 7HS and 7HL. A new phytosiderophore was discovered in both 7H and 7HL addition lines, which was identified to be 3-epihydroxy-2'-deoxymugineic acid by detailed nuclear magnetic resonance studies. These results revealed that in barley there are two pathways from 2'-deoxymugineic acid to 3-epihydroxymugineic acid: 2'-deoxymugineic acid → mugineic acid → 3-epihydroxymugineic acid and 2'-deoxymugineic acid → 3-epihydroxy-2'-deoxymugineic acid → 3-epihydroxymugineic acid. Barley genes encoding for the hydroxylations of phytosiderophores are located in different chromosomes and each gene hydroxylates different C-positions: the long arm of chromosome 4H carries the gene for hydroxylating the C-2' position and the long arm of chromosome 7H carries the gene for hydroxylating the C-3 position of the azetidine ring.

DOI： 10.1007/s004250050522

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KLUWER ACADEMIC PUBL  

To study genetic variation in crossability, 80 barley accessions of diverse geographic origin consisting of 50 wild barleys (H. vulgare ssp. spontaneum or ssp. agriocrithon) and 30 cultivated barleys (H. vulgare ssp. vulgare) were crossed as the male parent with a highly crossable wheat variety, Shinchunaga. Crossabilities, expressed as the percentage of pollinated florets giving embryo-containing caryopses, ranged from 0% to 68.6%. Barley accessions from East Asia had generally a low crossability, while barley accessions from other regions exhibited a wider range of crossability including highly crossable genotypes. No significant difference in mean crossability was found between wild and cultivated barleys. To estimate the number and location of barley genes controlling the crossability, doubled haploid lines derived from the cross between the barley varieties Steptoe and Morex were crossed as the male parent with wheat. Quantitative trait loci (QTL) analysis using molecular markers identified four QTL. These were mapped to the centromeric regions of chromosomes 2H, 3H and 5H and the short arm of chromosome 7H. The QTL on chromosomes 3H and 5H had larger effects than those on chromosomes 2H and 7H. The four QTL collectively explained 35.4% of the total variance under a multiple QTL model. Relationships of the QTL identified in the present study with previously reported crossability genes of barley and wheat are discussed.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GENETICS SOC JAPAN  

Seven dominant marker genes controlling morphological characters of barley were introduced into a wheat genetic background through hybridization between a Japanese bread wheat cultivar, Shinchunaga, and barley marker stocks. F-1 hybrids and their derivatives were analyzed by C-banding to confirm the presence and dosage of particular barley chromosomes carrying the marker genes. The genes for black lemma (B, located on chromosome 1H), pubescent leaf blade (Pub, 3H), hairy leaf sheath (Hs, 4H) and hooded lemma (K, 4H) were expressed in the F-1 hybrids, but generally to a lesser extent than in the parental barley accessions. F-1 hybrids having two copies of the B or Hs genes showed more pronounced phenotypes. In backcrossed progenies, each of which had a single copy of the barley marker gene in a hexaploid wheat background, the B and K phenotypes were less pronounced than in the F, hybrids, and the Pub phenotype was not observed. These four genes appear to be expressed in proportion to their dosage relative to the ploidy levels of the wheat background. The remaining three marker genes, brittle rachis (Bt-Bt2, 3H), blue aleurone (Pi, 4H) and short-upper-leaves (SuI) did not appear to express their characteristic phenotypes in any of the respective hybrids. Possible causes for reduced expression or complete suppression of the dominant barley genes in the wheat-barley hybrids are discussed. Dominant barley marker genes which are expressed in the hybrids would be useful for manipulating barley chromosomes in wheat backgrounds.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER VERLAG  

C-banding polymorphism was analyzed in eight strains of wild Emmer, Triticum dicoccoides Korn, which included six translocation homozygotes reported previously. Polymorphisms were detected in all of the strains examined, and the breakpoints of five spontaneous translocations were successfully identified by C-bands. Of the eight breakpoints that could be precisely identified, one was located in the centromeric region while the remaining seven were located in proximal to distal euchromatic regions. The two breakpoints of one translocation could only be approximately localized to proximal regions due to the scarcity of C-bands. The present results are in contrast with those observed on T. araraticum, another wild tetraploid wheat belonging to the Timopheevi group, in which most of the breakpoints were located in centromeric regions. In T. dicoccoides, the six translocation chromosome types were derived from the standard karyotype primarily by a mechanism other than centric breakage-fusion.

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Four bread wheat (Triticum aestivum L.) cultivars,'Aobakomugi', 'Chinese Spring', 'Norin 61' and 'Shinchunaga', were pollinated with five barley lines/cultivars consisting of three cultivated barley (Hordeum vulgare L.) lines, 'Betzes', 'Kinai 5' and OHL089, and two wild barley (Hordeum spontaneum C. Koch) lines, OUH602 and OUH324. Crossability, expressed as the percentage of embryo formation, varied from 0 to 55.4% among the cross combinations. The two wild barley lines generally had a higher crossability than the previously reported best pollinator, 'Betzes', and some Japanese wheat cultivars were better as the female parent than;Chinese Spring'. Ninety four hybrid plants were obtained from 250 embryos cultured, and their somatic chromosome numbers ranged from 21 to 36. Eighteen plants were mosaic in chromosome number. Twenty one-chromosome plants appeared most frequently (45.7%) followed by 28-chromosome plants (14.9%). C-banding analysis revealed that elimination of barley chromosomes was mainly responsible for the occurrence of aneuploid plants. In hypoploids derived from 'Betzes'-crosses, chromosome 5 was preferentially eliminated as previously reported, while in hypoploids derived from OUH602-crosses, chromosome 4 was preferentially eliminated. The wild barley line OUH602 may be a useful parent for producing a new wheat-barley addition set because of its high crossability with wheat and a different pattern of chromosome elimination.

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Language：Japanese   Publisher：The Crop Science Society of Japan  

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