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Molecular genetic analysis of the self-incompatibility locus in a wild species of sweet potato

野生甘薯自交不亲和位点的分子遗传学分析

基本信息

批准号：
13460003
负责人：
KOWYAMA Yasuo
金额：
$ 9.34万
依托单位：
Mie University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13460003/
关键词：
ipomoea trifida self-incompatibility genome analysis molecular genetics S-locus 遺伝子地図 BACライブラリー

项目摘要

Self-incompatibility (SI) in flowering plants is an elaborate genetic system that prevents self-fertilization and thereby promotes out-crossing to maintain generic diversity within a species. In a plant family, Convolvulaceae, several species of the genus ipomoea possess a sporophytic type of SI that causes a complete failure of pollen germination on the stigma surface after self-pollination. The SI system of Ipomoea is regulated by a single multiallelic locus called the S-locus. To identify the S-locus genes in Ipomoea, we used a positional cloning strategy based on a fine linkage map of DNA markers. Several genomic clones covering the S-locus were screened from bacterial artificial chromosome (BAC), λ and fosmid libraries that were constructed in the present study. Using the terminal end sequences of these clones, the S-locus region was further delimited within 0.6 cM, spanning ca. 300kb. Remarkable suppression of genetic recombination was detected in the S-locus region. From sequence analysis of the 313-kp region, 43 open reading frames (ORFs), many repetitive sequences and 5 transposable elements were predicted. Northern blot analysis of mRNAs isolated from reproductive and vegetative organs showed that five and four genes were specifically expressed in the stigma and anther-pollen, respectively. The present study made clear that these reproductive specific genes showed no homologies with the SI genes reported to date from other plants and suggests that a unique molecular mechanism is involved in the SI system of Convolvulaceae family.

开花植物的自交不亲和性（SI）是一个复杂的遗传系统，它阻止自花受精，从而促进异交，以保持物种内的属的多样性。在旋花科植物中，Ipomoea属的几个种具有孢子体类型的SI，其导致自花授粉后花粉在柱头表面完全不能萌发。Ipomoea的SI系统由称为S-位点的单个多等位基因位点调节。为了鉴定番薯属植物中的S位点基因，我们使用了基于精细连锁图的DNA标记的定位克隆策略。从构建的细菌人工染色体（BAC）文库、λ文库和fosmid文库中筛选出覆盖S位点的多个基因组克隆。使用这些克隆的末端序列，S-位点区域进一步被限定在0.6cM内，跨越约1000个碱基。300kb。在S-位点区域检测到显著的遗传重组抑制。通过对313-kp区域的序列分析，预测了43个开放阅读框架（ORF）、大量重复序列和5个转座因子。北方杂交分析表明，在柱头和花药花粉中分别有5个和4个基因特异表达。本研究表明，这些生殖特异基因与目前报道的其它植物SI基因没有同源性，提示旋花科SI系统具有独特的分子机制。