自交亲和与自交不亲和日本梨中S4基因的研究进展

综述了近20年日本梨中与自交亲和和自交不亲和有关的S4基因的研究进展。这些结果包括：“二十世纪”(基因型为S2S4)为自交不亲和品种，其突变品种“奥嗄二十世纪”(基因型 为S2S4SM，SM=stylar part mutant;花柱部分突变)为自交亲和型。“奥嗄二十世纪”自交亲和的原因有三点：(1)S4SM基因被删除或者是低水平表达。(2)S4SM基因仅在柱头表达。(3)S4SM基因表达较迟。这主要是由于“二十世纪”S基因座上的S4等位基因发生了高度突变成为S4SM基因或者S4等位基因被删除，导致其基因产物花柱中的S4-RNase受到高度抑制或缺乏的缘故。S4基因由997bp组成，其中85~768bp为684bp的阅读框，925~931bp和943~950bp为多聚腺苷酸信号。S4基因的表达产物为S4蛋白，S4蛋白由228个氨基酸残基组成，其中N端的27个氨基酸残基为信号肽，成熟的S4蛋白由201个氨基酸残基组成。S4蛋白的生理功能是抑制花粉的萌发和花粉管的伸长。

Achievements of S4-gene between self-compatible and self-incompatible Japanese pear cultivars

In this article,achievements about S4-gene between self-compatible and self-incompatible Japanese pear cultivars last 20 years were summariaed. The results were show as follow: Nijisseiki(S2S4) is a self-incompatible cultivar, and its self-compatible mutant, Osa-Nijisseiki (S2S4SM,SM=stylar part mutant) of Japanese Pear. The reason of the self-compatibility of Osa-Nijisseiki is considered as low expression of the S4SM-gene and the S4SM-gene expression only in stigma. and late expression of the S4SM. Osa-Nijisseiki is a variant of Nijisseiki in which the S4-allelic gene in the S-locus is exclusively mutated or deleted, causing severely impaired or suppressed expression of its gene product, S4-RNase, and the style. The amino acid sequence of S4-protein was 228 residues long, which comprised a 27-residue signal peptide and a 201-residue mature protein. S4-gene was composed of 997 bp including a 684 bp open reading frame of positions 85-768, there were two candidates for the putative polyadenylation signal of positions 925-931 and 943-950. S4-protein showed inhibitory effects on the pollen germination and the pollen tube growth.