薏苡ClSAD、ClFAD2基因单倍型鉴定与相关脂肪酸关联分析

Haplotype Identification of ClSAD/ClFAD2 and Association Analysis of Related Fatty Acids in Coix lacryma-jobi L.

薏苡仁油是薏苡仁主要功能性物质之一,脂肪酸是其重要组成部分。以中国9个省份的190份薏苡种质为材料,检测其种仁硬脂酸、油酸、亚油酸含量,分析ClSAD、ClFAD2基因序列多态性并鉴定单倍型,进行脂肪酸含量单倍型关联分析。结果表明,不同薏苡种质种仁3种脂肪酸含量存在广泛变异,变异系数为15.84%~23.05%,遗传多样性指数为5.22~5.23,其中油酸含量最高,硬脂酸含量最低,各脂肪酸组分间呈极显著正相关。ClSAD和ClFAD2内部各有14个和3个SNP,分别鉴定到5个单倍型组合,ClSAD基因单倍型Hap3和ClFAD2基因单倍型Hap1分别与参考基因组一致。ClSAD基因单倍型Hap3与硬脂酸含量显著关联且具有负效应,利于硬脂酸向油酸转化。ClFAD2基因单倍型Hap1利于亚油酸的积累,而Hap2与亚油酸酸含量显著关联且具有负效应,不利于亚油酸的合成。在2个基因内部各鉴定到1个关键SNP位点,分别是形成SAD和FAD2酶活性差异的关键位点。研究结果将为高油薏苡优良品种的选育、分子标记开发和相关分子机制解析提供理论基础。

Coicis oil is one of the main functional substances of coix seed,and fatty acid is an important component.The contents of stearic acid,oleic acid and linoleic acid in seed kernels of 190 coix germplasms from 9 provinces in China were detected.ClSAD and ClFAD2 sequences polymorphisms were analyzed and the haplotypes were identified.The haplotype association analysis of fatty acid content was carried out.The results showed that there were wide variations in the content of three fatty acids in the seeds of different coix germplasms,the coefficient of variation was 15.84%-23.05%,and the genetic diversity index was 5.22-5.23,among which the content of oleic acid was the highest and the content of stearic acid was the lowest,and there was a very significant positive correlation between the fatty acid components.There were 14 SNPs and 3 SNPs in ClSAD and ClFAD2,respectively,and 5 haplotype have been identified.The ClSAD haplotype Hap3 and ClFAD2 haplotype Hap1 are consistent with the reference genome,respectively.Hap3 of ClSAD was significantly associated with stearic acid content and had a negative effect on the conversion of stearic acid to oleic acid.Hap1 of ClFAD2 was favorable for linoleic acid accumulation,while Hap2 was significantly associated with linoleic acid content and had negative effects on linoleic acid synthesis.One key SNP locus was identified in each of the two genes,which was the key locus to the difference of SAD and FAD2 enzyme activity.The results will provide a theoretical basis for the breeding of high oil coix varieties,as well as the development of molecular markers and the analysis of related molecular mechanisms.