Abstract:

Stylar soluble proteins in self-incompatible “Nijisseiki” (S2S4), self-compatible “Osa-Nijisseiki” ( S2SSM4, SM means stylar-part mutant) and its progeny were analyzed by isoelectric focusing polyacrylamide gel electrophoresis (IEF-PAGE).SSM4-allele associated protein, SSM4-protein, existed in the style of “Osa-Nijisseiki” and its progeny. The SSM4-protein expressed only in the stigma of “Osa-Nijisseiki”, whereas in its original variety “Nijisseiki”, S4-protein expressed in the upper and lower parts of the style as well as in the stigma, and its expression amount decreased from the upper part to the lower part. The protein bands analyzed by IEF-PAGE were subjected to RNase activity staining. The results showed that the S4- and the SSM4-proteins have the similar molecular weights (approximately 30 kD) and RNase activity. The specific-activities measured with yeast RNA were similar, equivalent to approximately 275 U·min-1·mg-1 protein. The S SM4-protein showed almost the same inhibitory effects as the S4-protein on the pollen germination and the pollen tube growth with S4- and SSM4-alleles in vitro . From the above results, the reasons of the self-compatibility of “Osa-Nijisseiki” are considered as (1) low expression of the SSM4-gene and (2) the SSM4-gene expression only in stigma.

梨自交不亲和及其亲和突变品种花柱内s4(sSM4)基因的表达与作用的比较
张绍铃^1* 平土冢伸² 徐国华¹ 房经贵¹ 刘友良³

（1.  南京农业大学园艺学院，南京210095；2.  日本三重大学生物资源学部，日本津514-8507；
3. 南京农业大学农学院，南京210095）

摘要：提取梨(Pyrus serotina Rehd.)自交不亲和品种"二十世纪"(基因型为S2S4)、自交亲和的突变品种"奥嗄二十世纪"(S2S SM4,SM=Stylar-part mutant;花柱部分突变)及其亲和后代花柱的可溶性蛋白.经等电聚焦电泳(IEF-PAGE)分析表明,"奥嗄二十世纪"及其后代花柱仍存在SSM4蛋白,但其含量逐代减少,同时发现"奥嗄二十世纪"的S SM4基因仅在柱头表达,而"二十世纪"的S4基因表达的部位除了柱头外,还包括花柱上部及花柱下部,且表达量呈现从柱头到花柱下部下降的趋势.S蛋白经等电聚焦电泳的凝胶板进行RNase活性染色处理,也得到相同的结果.从花柱(包括柱头)中纯化出的S蛋白经SDS-PAGE电泳后进行RNase活性染色的结果表明 ,S4与SSM4蛋白的分子量相近(约30 kD),并且均具有RNase活性.进一步以酵母RNA为基质测定的比活性也基本相等,约为275 U·min-1·mg-1蛋白.在离体条件下,上述两种S蛋白(S-RNase)也以相同的程度抑制S4或SSM4花粉发芽及花粉管伸长.研究证明,自交亲和突变品种"奥嗄二十世纪"的SSM4基因也具有原始自交不亲和品种"二十世纪"S4基因的功能.因此,其自交亲和的原因可归结为SSM4基因的表达量较少及 SSM4基因仅在柱头中表达的缘故.

关键词： 梨；自交不亲和性；,S基因；S 蛋白；花粉管伸长

Key words: pear, self-incompatibility, S -genes, S-proteins, pollen tube growth