芸苔属植物自交不亲和性遗传机理研究及应用进展

Progress in Study on Genetic Mechanism of Self-incompatibilty in Brassica

芸苔属作物S位点上有三个紧密连锁的基因SLG,SRK,SCR/SP11。其中SRK和SCR/SP11蛋白分别为柱头和花粉SI信号识别决定因子。复等位基因显隐性关系与SRK基因的表达水平并不相关,可能是由于在绒毡层中SCR基因受到强烈的下游调控导致杂合体中隐性SCR基因在小孢子细胞中表达受到抑制。分子进化研究表明十字花科S位点基因的多态性来自于共同的祖先,并在不同种分化之前已经形成。利用芸苔属植物自交不亲和性遗传机理发展而来的PCR-RFLP方法提供了在芸苔属作物育种中切实可行的精确鉴定植株的S基因型和自交不亲和性的有效方法。

There were 3 tightly linked genes on the Brassica S locus. Among those ,SRK and SCR/SP11 respectively was the determinant of self- recognization specificity in stigma and pollen. The recessive and dominant relationships of S alleles in the Brassica stigma were not correlated with differences in SRK transcript levels. Nevertheless, the interaction exhibited in pollen was explained by severe down regulation of the recessive SCR allele in the tapetum and the lack of recessive SCR expression in microspores. Molecular analysis show that S locus genes were originated from the same ancestral species and S domain diversification predated the genus divergence. PCR-RFLP could provide us a more precise and practical marker assisted selection stratege for identification of S haplotypes in Brassica breeding.