小麦重要农艺性状的QTL定位与候选基因分析

QTL mapping and candidate gene analysis of important agronomic traits in wheat

关键词:  小麦, 农艺性状, 遗传连锁图谱, QTL定位, 候选基因分析

Key words:  wheat, agronomic traits, genetic linkage map, QTL mapping, candidate gene analysis

摘要:

小麦是世界三大主粮之一,重要农艺性状的QTL定位和候选基因分析有利于高产稳产新品种培育。为进一步揭示小麦农艺性状变异及育种改良,该研究选用小麦品种‘蜀麦969'与‘蜀麦830'构建了包含89个株系的重组自交系(F7)群体,利用简化基因组测序技术对重组自交系及其亲本进行了基因分型,结合农艺性状表型数据,采用完备区间作图方法鉴定了控制株高、穗下节长、芒长、穗长、旗叶长、旗叶宽、分蘖数、有效分蘖数和千粒重、粒长、粒宽、籽粒表面积的QTL位点。结果表明:(1)鉴定到27个农艺性状相关的QTL,分布在13个染色体上,可解释表型变异的3.74%～26.70%,其中,7B染色体608.58～609.12 Mb区间的QTL位点同时控制株高和穗下节长,这一位点在2个年份均被检测到; 5A染色体519.94～528.83 Mb区间的QTL同时控制分蘖数和有效分蘖数,而5D染色体437.38～439.30 Mb区间的QTL同时控制千粒重和籽粒表面积; 7个QTL位点与前人报道的位置相同。(2)在QTL定位区间开展功能基因预测,成功预测2个株高、4个分蘖和3个千粒重的候选基因,其中2个株高候选基因分别是编码富含亮氨酸重复序列受体样蛋白激酶家族蛋白和赤霉素2-氧化酶的基因; 4个分蘖候选基因分别是编码生长素反应蛋白、RING/U-box超家族蛋白和2个F-box蛋白的基因; 3个千粒重候选基因分别是编码富含亮氨酸重复序列受体样蛋白激酶家族蛋白、蛋白激酶家族蛋白和叶绿素a-b结合蛋白的基因。该研究鉴定的小麦重要农艺性状QTL位点,既为候选基因精细定位及克隆提供了依据,也可助力小麦新品种培育。

Abstract:

Wheat is one of three major staple crops in the world, QTL mapping and candidate gene analysis of important agronomic traits are beneficial for breeding new cultivars. In this study, the excellent wheat varieties Shumai 969 and Shumai 830 were used to construct a recombinant inbred line(F7)population consisting of 89 lines, and the reduced representation genome sequencing technology was carried out to genotype this population and its parents. In field, the phenotype of plant height, uppermost-internode length, awn length, spike length, flag leaf length, flag leaf width, tiller number, effective tiller number, thousand grain weight, grain length, grain width, and grain surface area were measured. The complete interval mapping method was employed to locate the QTL sites controlling these agronomic traits. The results were as follows:(1)A total of 27 QTLs were identified. These QTLs distributed on 13 distinct chromosomes, and explained 3.74% to 26.70% of the phenotypic variation of the agronomic traits. Among them, the QTL in the 608.58-609.12 Mb interval on chromosome 7B controlled both plant height and uppermost-internode length, which was identified by two years. The QTL in the 519.94-528.83 Mb interval on chromosome 5A controlled both tiller number and effective tiller number, and the QTL in the 437.38-439.30 Mb interval on chromosome 5D controlled both thousand grain weight and grain surface area. 7 QTLs located in the same positions as previously reported.(2)Functional gene prediction within the QTL intervals successfully predicted two candidate genes associated with plant height traits, four candidate genes linked to tiller traits, and three candidate genes attributed to thousand grain weight within the mapped interval. The two candidate genes of plant height encoded a leucine-rich repeat receptor-like protein kinase family protein and a gibberellin 2-oxidase. The four candidate genes of tiller encompassed a auxin response protein, a RING/U-box superfamily protein, and two F-box proteins. The three candidate genes for the thousand grain weight encoded a leucine-rich repeat receptor-like protein kinase family protein, a protein kinase family protein, and a chlorophyll a-b-binding protein. The identified QTLs and predicted major genes in this research established a foundation for the meticulous mapping and cloning of the candidate genes controlling the corresponding agronomic traits, and benefited breeding new wheat cultivars.