大麦抗旱候选基因的关联分析和功能标记的开发

项目名称： 大麦抗旱候选基因的关联分析和功能标记的开发

项目编号： No.30871526

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 郭培国

作者单位： 广州大学

项目金额： 34万元

中文摘要： 探讨抗旱候选基因的多态性与抗旱性状的关系是开发功能标记的最佳方法。据此，本研究利用遗传背景差异较大且在抗旱性上具有多样性的大麦种质作自然群体，选用我们研究所得的抗旱候选基因，运用Ecotilling技术发现四个候选基因(即编码HSP17.8、CABP、CSMO和P5CS四个基因)存在67个SNP/INDEL类型的多态性；结合测定自然群体各材料抗旱相关的表型性状数据，运用TASSEL软件对候选基因多态性与表型性状间开展基于连锁不平衡的关联分析，发现9个SNPs/INDELs至少一个与产量、生物量、千粒重、穗长、株高、甜菜碱和叶绿素含量等密切相关，它们解释的表型性状变异百分数在4.4-9.1%之间。这些SNPs/INDELs已设计出特异的引物组合，可作为具基因信息的功能标记用于多种遗传背景大麦材料的筛选。对候选基因存在的所有SNPs/INDELs作进一步分析发现，有7个是可导致蛋白特性出现变化的错义突变，其中有5个在HSP17.8基因的编码区，2个在CABP基因的编码区。自然选择与进化分析表明HSP17.8、CSMO和CABP基因具有人工和自然选择的痕迹，表明这些基因与环境的适应性相关。

中文关键词： 大麦；抗旱候选基因；抗旱性状；关联分析；功能标记

英文摘要： Functional markers associated with drought tolerance (DT) could improve selection efficiency for DT cultivars in barley breeding program. One of the best approaches for developing functional markers is to conduct the association analysis between the polymorphisms of DT candidate genes and DT phenotypic traits. In this study, the barley germplasm with diverse genetic backgrounds and different degrees of drought tolerance was considered as the natural population. Genes, which identified from our previous research in barley, were considered as DT candidate genes. The polymorphisms of these candidate genes among the natural population were investigated through Ecotilling technology. A total of 67 variations including SNPs (single nucelotide polymorphisms) and INDELs (insert/deletions) were identified in four candidate genes which encode heat-shock protein 17.8 (HSP 17.8), a chlorophyll a/b-binding protein (CABP), C-4 sterol methyl oxidase (CSMO) and Δ8242;-pyrroline-5-carboxylate synthetase (P5CS). The association mapping was performed between gene polymorphisms and DT traits using TASSEL software with general linear model, 9 SNPs/INDELs were detected to be associated with at least one of DT traits which are grain yield, biomass, 1000 kernal weight, plant height, spike length, betaine content and chlorophyll content. These SNPs/INDELs explain 4.4 to 9.1% of phenotypic variations for corresponding DT traits. The specific primer combinations were designed for these SNPs/INDELs, the developed markers could be considered as functional markers for the selection of DT marterials in barley. In addition, the perporties of all SNPs/INDELs in four candidate genes were further analyzed. Seven missense varitions predicted to be deleterious to protein function were observed, five are in the coding region of HSP17.8 gene and two in the coding region of CABP gene. The analysis of natural selection and evolution shows that genes of HSP17.8, CSMO and CABP are likely to be target genes for artificial and natural selection, indicating these three genes could be related to the adaptation for environments.

英文关键词： Barley; Drought tolerant candidate gene; Drought tolerant trait; Association analysis; Functional marker