用全基因组关联分析解析籼稻垩白的遗传基础

摘要

In order to dissect the genetic bases and mine novel alleles of grain chalkiness in indica, we conducted an experiment with genome-wide association analysis using phenotypic data collected from multiple locations (Sanya of Hainan, Shenzhen of Guangdong, Hangzhou of Zhejiang, and Jingzhou of Hubei) and 6704 re-sequenced SNP markers distributed in whole genome for 272 indica mini-core germplasm collected worldwide. All accessions were classified into three subpopulations based on SNP data. Total of 42 and 44 loci were detected as significant associations with percentage of grains with chalkiness (PGWC) and degree of endosperm chalkiness (DEC), respectively, which distributed all over the 12 chromosomes. Twenty one and nineteen loci were stably expressed for PGWC and DEC in multiple locations, respectively, and 12 simultaneously affected the two traits. Eleven of the said loci were co-located in the same or near regions harboring the quality genes cloned previously. Of them, the region of 3.3–5.3 Mb on chromosome 5 was significantly associated with PGWC at all four locations, having the largest phenotypic contri-bution detected in Hangzhou location, and the carrier variety with the best favorable allele was IRGC121689;another region of 17.5–22.7 Mb on chromosome 12 was significantly associated with DEC at Sanya and Hangzhou, having the largest phenotypic contribution detected in Sanya, and the carrier variety with the best favorable allele was IRGC122285. These loci and germplasms are important potential genes and variety resources that can be used in molecular breeding for rice appearance quality.%利用272份全球籼稻微核心种质的重测序SNP基因型,对海南三亚、广东深圳、浙江杭州和湖北荆州4个地点收集到的垩白粒率和垩白度性状采用 TASSEL 软件进行全基因组关联分析,解析籼稻垩白的遗传基础和挖掘影响垩白粒率和垩白度的优异等位基因。结果表明,依据 SNP 数据,可将籼稻微核心种质分成3个亚群。4个地点分别检测到42个和44个与垩白粒率和垩白度显著关联的位点,位于全部12条染色体上。2个性状分别有21个和19个位点在2个以上环境下同时被检测到,这些位点中有12个位点同时影响垩白粒率和垩白度,11个位点附近都有已克隆的水稻品质相关基因。其中,第5染色体3.3~5.3 Mb区间在4个地点都被检测到与垩白粒率显著关联,以杭州点对垩白粒率的贡献最大,优异等位基因载体品种为IRGC121689；第12染色体的17.5~18.0 Mb区间在三亚和杭州都被检测到与垩白度显著关联,以三亚点的垩白度贡献最大,优异等位基因载体品种为IRGC122285。这些位点和品种资源可作水稻外观品质分子改良的重要基因和品种资源。