Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.stress.2024.100700

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

Interspecific F1 hybrids between Asian (Oryza sativa) and African rice (Oryza glaberrima) exhibit severe sterility caused by the accumulation of hybrid sterility genes/loci at 15 or more loci. The mechanisms underlying the hybrid sterility genes are largely unknown; however, a few genes associated with the killer-protector system, which is the system most frequently associated with hybrid sterility genes, have been identified. We previously produced fertile plants as tetraploids derived from diploid interspecific F1 hybrids through anther culture; therefore, it was suggested that hybrid sterility could be overcome following tetraploidization. We investigated whether tetraploid interspecific plants produced by crossing are fertile and tested the involvement of hybrid sterility genes in the process. Fertile tetraploid interspecific F1 hybrid plants were obtained by crossing two tetraploids of Oryza sativa and Oryza glaberrima. To elucidate the relationships between pollen fertility and the hybrid sterility loci in the tetraploid F1 microspores, we performed genetic analyses of the tetraploid F2 hybrids and diploid plants obtained from the microspores of tetraploid interspecific hybrids by anther culture. The result suggested that the tetraploid interspecific hybrids overcame pollen and seed infertility based on the proportion of loci with the killer-protector system present in the tetraploids. The heterozygous hybrid sterility loci with the killer-protector system in the tetraploid segregate the homozygous killed allele (16.7-21.4%), with more than three-quarters of the gametes surviving. We theoretically and experimentally demonstrated that fertile rice progenies can be grown from tetraploid interspecific hybrids.

DOI： 10.1093/genetics/iyae104

PubMed

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Publishing type：Research paper (scientific journal)   Publisher：International Society of Cytology  

DOI： 10.1508/cytologia.88.167

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Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Breeding  

DOI： 10.1270/jsbbs.22058

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

<title>Abstract</title>
<sec>
<title>Background and Aims</title>
Cold stress in rice (Oryza sativa) plants at the reproductive stage prevents normal anther development and causes pollen sterility. Tapetum hypertrophy in anthers has been associated with pollen sterility in response to cold at the booting stage. Here, we re-examined whether the relationships between anther abnormality and pollen sterility caused by cold stress at the booting stage in rice can be explained by a monovalent factor such as tapetum hypertrophy.


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<sec>
<title>Methods</title>
After exposing plants to a 4-d cold treatment at the booting stage, we collected and processed anthers for transverse sectioning immediately and at the flowering stage. We anatomically evaluated the effect of cold treatment on anther internal morphologies, pollen fertilities and pollen numbers in the 13 cultivars with various cold sensitivities.


</sec>
<sec>
<title>Key Results</title>
We observed four types of morphological anther abnormalities at each stage. Pollen sterility was positively correlated with the frequency of undeveloped locules, but not with tapetum hypertrophy as commonly believed. In cold-sensitive cultivars grown at low temperatures, pollen sterility was more frequent than anther morphological abnormalities, and some lines showed remarkably high pollen sterility without any anther morphological alterations. Most morphological anomalies occurred only in specific areas within large and small locules. Anther length tended to shorten in response to cold treatment and was positively correlated with pollen number. One cultivar showed a considerably reduced pollen number, but fertile pollen grains under cold stress. We propose three possible relationships to explain anther structure and pollen sterility and reduction due to cold stress.


</sec>
<sec>
<title>Conclusions</title>
The pollen sterility caused by cold stress at the booting stage was correlated with the frequency of entire locule-related abnormalities, which might represent a phenotypic consequence, but not a direct cause of pollen abortion. Multivalent factors might underlie the complicated relationships between anther abnormality and pollen sterility in rice.


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DOI： 10.1093/aob/mcab091

PubMed

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Other Link： http://academic.oup.com/aob/advance-article-pdf/doi/10.1093/aob/mcab091/39738009/mcab091.pdf

Publisher：Japanese Society of Breeding  

DOI： 10.1270/jsbbr.26.w04

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Publisher：Japanese Society of Breeding  

DOI： 10.1270/jsbbr.25.w07

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Publisher：Japanese Society of Breeding  

DOI： 10.1270/jsbbr.24.w01

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Publisher：Japanese Society of Breeding  

DOI： 10.1270/jsbbr.22.w07

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Event date： 2021

Language：Japanese  

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Event date： 2021

Language：Japanese  

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JST 次世代研究者挑戦的研究プログラム JPMJSP2119

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