玉米子粒脂肪含量的全基因组关联分析

Genome-wide Association Analysis of Fat Content in Maize

利用分子标记对控制玉米脂肪合成的关键基因进行定位,从分子水平上阐明其遗传机理,提高高油玉米的育种效率。以吉林省80份核心玉米自交系为关联群体,2014年和2015年分别在吉林农业大学试验地进行田间试验,将自交收获的果穗晾晒脱粒后用NIRFlex N-500近红外光谱仪测定其子粒脂肪含量。同时使用Illumina PE150测序仪对80份玉米自交系进行全基因组重测序,共获得1 490 007个高质量的SNP用于后续的关联分析。结果表明,玉米子粒脂肪含量的变异范围为2.83%-6.81%,广义遗传力为63.3%。经过两年1点的全基因组关联分析共筛选得到10个SNP位点与子粒的脂肪含量显著关联（P〈0.000 001）,解释的表型贡献率为0.65%-34.5%,其中位于染色体框4.01的SNP标记表型贡献率最高为34.5%。在显著性SNP位点（P〈0.000 001）的连锁不平衡区域（5.2 kb）内共挖掘出6个候选基因,分别预测编码MYB转录因子、果胶酯酶、谷氨酰胺合成酶和3种无特征功能的假定蛋白,可能与脂肪的合成代谢密切相关,可为高油玉米材料的分子标记辅助选择及克隆调控玉米子粒脂肪含量的关键基因提供参考。

The key genes for the control of maize fat synthesis were located by molecular markers, and its genet-ic mechanism was clarified at the molecular level, which can improve the efficiency of high-oil corn breeding. Inthis experiment, 80 maize core inbred lines in Jilin province were used as related groups, in the two years of 2014-2015, the field trials were conducted in Jilin Agricultural University experimental ground. The self-pollinated earwas dried and threshed, and its grain fat content was determined by NIRFlex N-500 near-infrared spectroscopy.Whole genome resequencing of 80 maize core inbred lines was carried out by Illumina PE150 sequencer, a total of 1 490 007 high-quality SNPs were obtained for subsequent association analysis. The results showed that the varia-tion of fat content was in the range of 2.83%-6.81%, and the generalized heritability was 63.3%. After two years ofgenome-wide association analysis, 10 SNP loci were significantly associated with the fat content of the grains（P〈0.000 001）, the phenotypic contribution rate of the phenotype was 0.65%-34.5%, and the SNP marker in chromo-some frame 4.01 was 34.5%. Six candidate genes were excavated in the linkage disequilibrium region（5.2 kb） of thesignificant SNP loci（P〈0.000 001）, which predicted to encode MYB transcription factors, pectinase, glutamine syn-thetase and 3 A hypothetical protein with no characteristic function, it may be closely related to the synthetic metab-olism of fat. The results of this study have laid a foundation for the molecular marker-assisted selection of high-oilmaize materials and cloning the key genes of corn grain fat synthesis.