Abortion of germ cells and reproductive barriers due to maladaptive haplotype block in rice

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05576
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39010:Science in plant genetics and breeding-related
• Research Institution: Kyushu University
• Principal Investigator: Yamagata Yoshiyuki 九州大学, 農学研究院, 准教授 (00600446)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 雑種不稔 / 生殖的隔離 / 減数分裂 / イネ / ハプロタイプ

Outline of Final Research Achievements

Reproductive isolation acts as a barrier to maintaining species identity. In interspecific hybrids of cultivated rice Oryza sativa and O. glaberrima, S18 gene causes abnormal germ cell morphology, high pollen sterility and segregation distortion in heterozygotes. In this study, we found that the S18 non-adaptive haplotype is composed of a gene complex consisting of two loci, S18B and S18T, and that both regions induce high sterile on heterozygotes due to delayed and incomplete degradation of tapetal cells. We have also identified the nucleotide substitutions responsible for the high sterility by forward genetics, and diversity analysis in AA genome species revealed that S18 originated from O. barthii.

Free Research Field

遺伝育種学分野

Academic Significance and Societal Importance of the Research Achievements

病虫害、温暖化や豪雨などの気候変動などの影響に対して堅牢な作物を開発するため、古くから野生種との交雑が行われてきた。しかし、種間交雑における雑種致死や不稔により野生種の持つ有用な性質を栽培種に取り込むことがしばしば困難とある。本研究ではイネ科作物において広く見いだされるタンパク質のアミノ酸置換が雑種不稔を引き起こすことを明らかにした。最近はゲノム編集による塩基置換が可能な状況となっており、ゲノム編集技術等を活用することで、生殖的隔離の打破や制御を可能にし、育種への活用につながることが期待される。