Fine mapping of Hwc1 and Hwc2, two complementary hybrid weakness gene in rice

水稻两个互补杂交弱点基因 Hwc1 和 Hwc2 的精细定位

基本信息

批准号：
16580001
负责人：
KUBOYAMA Tsutomu
金额：
$ 2.43万
依托单位：
College of Agriculture, Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16580001/
关键词：
hybrid weakness reproductive barrier Oryza sativa Japonica Jamaica mapping complementary dominant root growth イネ根の伸長異常遺伝子単離 map based cloning 連鎖非平衡

项目摘要

Hybrid weakness is a reproductive barrier that is found in many plant species. In rice, the hybrid weakness caused by two complementary genes, Hwc1 and Hwc2, has been surveyed intensively. However, their gene products and the molecular mechanism that causes hybrid weakness have remained unknown. We performed linkage analyses of Hwc1, narrowed down the area of interest to 60 kb, and identified eight candidate genes. In the F_2 population, in which both Hwc1 and Hwc2 genes were segregated, plants were separable into four classes according to their respective phenotypes: severe type, semi-severe type, F_1 type, and normal type. Severe type plants show such severe symptoms that they could produce only tiny shoot-like structures; they were unable to generate roots. Genetic analyses using closely linked DNA markers of the two genes showed that the symptoms of the F_2 plants were explainable by the genotypes of Hwc1 and Hwc2. Weakness was observed in plants that have both Hwc1 and Hwc2. In Hwc1 homozygote, the symptoms worsened and severe type or semi-severe type plants appeared. Consequently, Hwc1 should have a gene dosage effect and be a semi-dominant gene. The dosage effect of Hwc2 was recognizable, but it was not so severe as that in Hwc1. These results are useful to elucidate the mechanism that causes the hybrid weakness phenomenon and the role of each causal gene in hybrid weakness.

杂种弱点是许多植物物种中发现的繁殖障碍。在水稻中，由两个互补基因 Hwc1 和 Hwc2 引起的杂交弱点已得到深入研究。然而，它们的基因产物和导致杂交弱点的分子机制仍然未知。我们对 Hwc1 进行了连锁分析，将感兴趣的区域缩小到 60 kb，并确定了 8 个候选基因。在Hwc1和Hwc2基因均分离的F_2群体中，植物根据其各自的表型可分为四类：严重型、半严重型、F_1型和正常型。严重型植物表现出如此严重的症状，以至于它们只能产生微小的芽状结构；他们无法产生根。使用两个基因紧密连锁的 DNA 标记进行遗传分析表明，F_2 植物的症状可以通过 Hwc1 和 Hwc2 的基因型来解释。在同时具有 Hwc1 和 Hwc2 的植物中观察到弱点。 Hwc1纯合子中，症状加重，出现重症型或半重症型植株。因此，Hwc1应该具有基因剂量效应并且是半显性基因。 Hwc2 的剂量效应是可识别的，但没有 Hwc1 中的那么严重。这些结果有助于阐明导致杂交弱点现象的机制以及每个因果基因在杂交弱点中的作用。