Gain of deleterious function causes an autoimmune response and Bateson–Dobzhansky–Muller incompatibility in rice

2.453
Eiji Yamamoto, Tomonori Takashi, Yoichi Morinaka, Shaoyang Lin, Jianzhong Wu, Takashi Matsumoto, Hidemi Kitano, Makoto Matsuoka, Motoyuki Ashikari
Molecular Genetics and Genomics, 2010, 283(4): 305-315  DOI: 10.1007/s00438-010-0514-y;      追溯原文......本站官方QQ群:62473826
Rice - Reproductive isolation - BDM incompatibility - Autoimmune response - Weakness phenotype

Reproductive isolation plays an important role in speciation as it restricts gene flow and accelerates genetic divergence between formerly interbreeding population. In rice, hybrid breakdown is a common reproductive isolation observed in both intra and inter-specific crosses. It is a type of post-zygotic reproductive isolation in which sterility and weakness are manifested in the F2 and later generations. In this study, the physiological and molecular basis of hybrid breakdown caused by two recessive genes, hbd2 and hbd3, in a cross between japonica variety, Koshihikari, and indica variety, Habataki, were investigated. Fine mapping of hbd2 resulted in the identification of the causal gene as casein kinase I (CKI1). Further analysis revealed that hbd2-CKI1 allele gains its deleterious function that causes the weakness phenotype by a change of one amino acid. As for the other gene, hbd3 was mapped to the NBS-LRR gene cluster region. It is the most common class of R-gene that triggers the immune signal in response to pathogen attack. Expression analysis of pathogen response marker genes suggested that weakness phenotype in this hybrid breakdown can be attributed to an autoimmune response. So far, this is the first evidence linking autoimmune response to post-zygotic isolation in rice. This finding provides a new insight in understanding the molecular and evolutionary mechanisms establishing post-zygotic isolation in plants.

有害的功能获得导致水稻自身免疫应答和Basteson-Dobzhansky-Muller不亲和

生殖隔离对物种形成起着重要的作用,因为其限制了之前能够互交群体间的基因交流,加速了群体的遗传差异。水稻中,杂交衰退在种间和种内杂交均能发生,是一种常见的生殖隔离形式。杂种衰退属于配子后的生殖隔离,在F2及其后代出现不育和弱势的表型。本研究对粳稻品种Koshihikari和籼稻品种Habataki杂交后代杂种衰退的生理基础进行了研究,并对造成杂种衰退的两个隐性基因hbd2和hbd3进行了遗传分析。通过精细定位发现hbd2是一个酪蛋白激酶1基因(CKI1)。进一步分析揭示hbd2-CKI1等位基因由于单个氨基酸的变化使之获得了有害的功能。另一个基因hbd3被定位到一个NBS-LRR基因簇区域内。NBS-LRR基因是一类最常见的R基因,能够对病原菌攻击进行响应,从而触发免疫信号的传递。对病原菌应答标记基因进行表达分析,发现杂种衰退的弱势表型可能是由于自身免疫应答引发的。本研究首次将水稻配子后生殖隔离和自身免疫应答联系起来。这个研究为我们理解植物配子后生殖隔离的分子和演化机理提供了新的发现。


基因列表
  杂种衰退;酪蛋白激酶 hbd2; OsCKI1; LTG1; LTRPK1
  杂种衰退 hbd-3