Long Yunming, Zhao Lifeng, Niu Baixiao, Su Jing, Wu Hao, Chen Yuanling, Zhang Qunyu, Guo Jingxin, Zhuang Chuxiong, Mei Mantong, Xia Jixing, Wang Lan, Wu Haibin, Liu Yao-Guang
Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Province, College of Life Sciences, South China Agricultural University, Wushan, Guangzhou 510642, China.
Proc Natl Acad Sci U S A. 2008 Dec 2;105(48):18871-6. doi: 10.1073/pnas.0810108105. Epub 2008 Nov 24.
Sterility is common in hybrids between divergent populations, such as the indica and japonica subspecies of Asian cultivated rice (Oryza sativa). Although multiple loci for plant hybrid sterility have been identified, it remains unknown how alleles of the loci interact at the molecular level. Here we show that a locus for indica-japonica hybrid male sterility, Sa, comprises two adjacent genes, SaM and SaF, encoding a small ubiquitin-like modifier E3 ligase-like protein and an F-box protein, respectively. Most indica cultivars contain a haplotype SaM(+)SaF(+), whereas all japonica cultivars have SaM(-)SaF(-) that diverged by nucleotide variations in wild rice. Male semi-sterility in this heterozygous complex locus is caused by abortion of pollen carrying SaM(-). This allele-specific gamete elimination results from a selective interaction of SaF(+) with SaM(-), a truncated protein, but not with SaM(+) because of the presence of an inhibitory domain, although SaM(+) is required for this male sterility. Lack of any one of the three alleles in recombinant plants does not produce male sterility. We propose a two-gene/three-component interaction model for this hybrid male sterility system. The findings have implications for overcoming male sterility in inter-subspecific hybrid rice breeding.
不育现象在不同种群的杂交后代中很常见，比如亚洲栽培稻（Oryza sativa）的籼稻和粳稻亚种之间。尽管已经鉴定出多个导致植物杂种不育的基因座，但这些基因座的等位基因在分子水平上如何相互作用仍不清楚。在此我们表明，一个控制籼粳杂种雄性不育的基因座Sa由两个相邻基因组成，即SaM和SaF，它们分别编码一个类泛素小修饰物E3连接酶样蛋白和一个F-box蛋白。大多数籼稻品种含有单倍型SaM(+)SaF(+)，而所有粳稻品种都具有SaM(-)SaF(-)，这是在野生稻中通过核苷酸变异而分化形成的。这种杂合复合基因座中的雄性半不育是由携带SaM(-)的花粉败育引起的。这种等位基因特异性的配子消除是由于SaF(+)与截短蛋白SaM(-)之间的选择性相互作用导致的，而由于存在一个抑制结构域，SaF(+)与SaM(+)不发生相互作用，尽管SaM(+)对于这种雄性不育是必需的。重组植株中缺少这三个等位基因中的任何一个都不会产生雄性不育。我们提出了一个针对这种杂种雄性不育系统的双基因/三组分相互作用模型。这些发现对于克服亚种间杂交水稻育种中的雄性不育具有重要意义。
