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Studies on the differentiation of genepools in rice

水稻基因库分化研究

基本信息

批准号：
09306001
负责人：
SANO Yoshio
金额：
$ 21.57万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

Plant breeding is mainly to select favorable gene combinations from naturally occurring variants through hybridization. Since species have the primary genepool which is used as the genetic materials for their adaptation, the differential genepool is closely related with the difficulties in hybridization breeding. The objectives of the present study is to reveal the differentiated genepool among rice taxa and to examine the causal factors. The genic diversity was examined regarding to Wx and C genes controlling amylose content and anthocyanin coloration since these variations are distinct among cultivars than in wild relative regardless of the genetic bottleneck effects during the rice domestication. Sequence data of the Wx gene revealed that at least 5 alleles have been established after the domestication. The alleles resulted from frameshifts and changes in RNA processing and amino acids. The C gene showing allelic diversity in rice cultivars was found to be the homolog of maize cl encoding Myb-like protein.Sequence data showed that the frequency of non-synonymous mutations was high in the C of rice cultivars than the wild progenitor, indicating that such alteration in C might have been positively selected for during the domestication process. The internal barriers were also examined since they act as the mechanism of differentiated genepools. A hybrid sterility gene, S10, was located near wx and the candidate was detected by fine mapping and gene expression. In addition, at least 3 genes on chromosome 6 were found to play a significant role for cross-incompatibity in rice. The results will contribute for their molecular clonning to figure out their molecular evolution during the differentiation of genepools in rice.

植物育种主要是通过杂交从自然发生的变异体中筛选出有利的基因组合。由于物种具有作为其适应的遗传物质的初级遗传库，差异遗传库与杂交育种的困难密切相关。本研究的目的是揭示水稻类群之间的差异基因库，并研究其原因。对控制直链淀粉含量和花青素着色的Wx和C基因的遗传多样性进行了研究，因为这些变异在不同品种之间是不同的，而不考虑水稻驯化过程中的遗传瓶颈效应。Wx基因的序列分析表明，驯化后至少建立了5个等位基因。这些等位基因是由框架移位、RNA加工和氨基酸的变化引起的。在水稻品种中，C基因表现出等位基因多样性，与编码Myb蛋白的玉米C基因同源，测序数据表明，水稻品种C基因的非同义突变频率高于野生祖先，这表明C基因的这种改变可能是在驯化过程中正向选择的。这些内部屏障也被研究过，因为它们是分化成胚醇的机制。杂交不育基因S10位于Wx附近，通过精细定位和基因表达检测到该候选基因。此外，还发现6号染色体上至少有3个基因在水稻杂交不亲和性中起重要作用。这些结果将有助于对它们进行分子克隆，以了解它们在水稻胚胎醇分化过程中的分子进化。