‘奥嗄二十世纪’梨自交亲和性分子机制及遗传特性研究

Molecular Mechanism and Genetic Characterization of Self-compatibility in Pear ‘Osa-Nijisseiki’

‘奥嗄二十世纪’是自交不亲和梨品种‘二十世纪’的自交亲和花柱突变体,花粉自交不亲和功能正常,其自交亲和性突变的分子机制及遗传特性目前仍有争议。本研究中通过田间自花及相互授粉以及基因组、mRNA转录和蛋白质水平比较,分析‘奥嗄二十世纪’、‘二十世纪’及其后代S-RNase基因的存在与否、表达特性及其在后代中的遗传。结果显示,‘奥嗄二十世纪’花柱S2-RNase基因的核苷酸序列和表达特性与其原始品种‘二十世纪’完全一致;而S4-RNase基因信号比其原始品种‘二十世纪’弱,在花柱中正常表达(包括转录和翻译水平),但表达量低;在‘奥嗄二十世纪’的自交亲和后代基因组中检测不到S4-RNase基因。本研究表明,‘奥嗄二十世纪’基因组中存在花柱S4-RNase基因,但不能遗传给后代。

Pear ‘Osa-Nijisseiki’ is a stylar-specific self-compatible （SC） mutant from ‘Nijisseiki’ which exhibit S-RNase-mediated gametophytic self-incompatibility. The mechanism underlying SC was not clear though many investigations have been carried out. In the present study, the S-RNase genes in ‘Osa-Ni- jisseiki’ and its SC progenies were systematically investigated at genomic, transcriptional and translational level in comparison with its wild type,‘Nijisseiki’. Results showed that both‘ Osa-Nijisseiki’ and‘Nijisseiki’ showed no differences in performances of S2-RNase gene, but the former produced less S4-RNase gene signals than the latter did. However, S4-RNase genes were absent in progeny of ‘Osa-Nijisseiki’. It could be conclu- ded that S4-RNase in ‘ Osa-Nijisseiki’ gene does present in the genome and express, but could not be transmitted sexually.