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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=stylarpartmutant;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。
The research progress of S4 gene related to self-compatibility and self-incompatibility in Japanese pear in recent 20 years is reviewed. These results include: “Twentieth Century” (genotype S2S4) is self-incompatible and its mutant variety “Austrian XX century” (genotype S2S4SM, SM = stylarpartmutant; style part of the mutation) is selfed Affinity type. There are three reasons why Austrian Twentieth Century self-compatibility is due: (1) the S4SM gene is deleted or is expressed at low levels. (2) S4SM gene is expressed only in stigma. (3) S4SM gene expression later. This is mainly due to a high degree of mutation of the S4 allele at the S locus of the “Twentieth Century”, which resulted in the deletion of the S4SM gene or the S4 allele, resulting in a highly suppressed or absent S4-RNase in the flower of its gene product . The S4 gene consists of 997bp, of which 68 ~ 768bp is the reading frame of 684bp, 925 ~ 931bp and 943 ~ 950bp are polyadenylation signals. The expression product of S4 gene is S4 protein, and the S4 protein consists of 228 amino acid residues, of which 27 amino acid residues at the N terminal are signal peptides and the mature S4 protein is composed of 201 amino acid residues. The physiological function of the S4 protein is to inhibit pollen germination and pollen tube elongation.