Lineage-specific gene acquisition or loss is involved in interspecific hybrid sterility in rice
Lineage-specific gene acquisition or loss is involved in interspecific hybrid sterility in rice
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DOI：
10.1073/pnas.1711656115
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发表时间：
2018-02-27
影响因子：
11.1
通讯作者：
Kanazawa, Akira
中科院分区：
文献类型：
--
作者：
Koide, Yohei;Ogino, Atsushi;Kanazawa, Akira
了解物种间繁殖障碍的遗传基础一直是进化生物学的核心问题。水稻S-1基因座是水稻杂种不育的主要原因，是两种水稻之间的主要生殖屏障。在s -1(g)/ s -1(s)杂合子中，O. glaberria来源的等位基因（记为s -1(g)）与其等位基因替代物（记为s -1(s)）导致配子优先败育。在这里，我们通过诱变和筛选可育杂交植株，分离出一种具有等位基因s -1（mut）的突变体，该突变体在s -1(mut)/ s -1(g)和s -1(mut)/ s -1(s)杂种中不具有不育性。我们发现S-1（mut）等位基因的原因突变是S-1位点上肽酶编码基因（标记为“SSP”）的缺失。水稻基因组中未发现SSP的同源基因。转化实验表明，在s -1(s)等位基因携带者中引入SSP不会诱导不育。在s -1(mut)/ s -1(s)杂合子中，SSP的插入导致不育，这表明SSP弥补了突变体功能表型的缺失，这一现象涉及多种因素。遗传特异性获得或丢失SSP基因引起的多态性与杂交不育的产生有关。我们的研究结果表明，人为破坏繁殖屏障的单个基因会产生一个“中性”等位基因，这有利于育种计划的种间杂交。
Understanding the genetic basis of reproductive barriers between species has been a central issue in evolutionary biology. The S-1 locus in rice causes hybrid sterility and is a major reproductive barrier between two rice species, Oryza sativa and Oryza glaberrima. The O. glaberrima-derived allele (denoted S-1(g)) on the S-1 locus causes preferential abortion of gametes with its allelic alternative (denoted S-1(s)) in S-1(g)/S-1(s) heterozygotes. Here, we used mutagenesis and screening of fertile hybrid plants to isolate a mutant with an allele, S-1(mut), which does not confer sterility in the S-1(mut)/S-1(g) and S-1(mut)/S-1(s) hybrids. We found that the causal mutation of the S-1(mut) allele was a deletion in the peptidase-coding gene (denoted "SSP") in the S-1 locus of O. glaberrima. No orthologous genes of SSP were found in the O. sativa genome. Transformation experiments indicated that the introduction of SSP in carriers of the S-1(s) allele did not induce sterility. In S-1(mut)/S-1(s) heterozygotes, the insertion of SSP led to sterility, suggesting that SSP complemented the loss of the functional phenotype of the mutant and that multiple factors are involved in the phenomenon. The polymorphisms caused by the lineage-specific acquisition or loss of the SSP gene were implicated in the generation of hybrid sterility. Our results demonstrated that artificial disruption of a single gene for the reproductive barrier creates a "neutral" allele, which facilitates interspecific hybridization for breeding programs.