大豆不饱和脂肪酸含量全基因组关联分析

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Abstract： Soybean，as one of the important oilseed crops，derives its nutritional value primarily from the composition and content of unsaturated fatt acids （UFAs） in its oil.The relative proportions of UFA components critically influence the qualityof soybean and are closely associated with consumer health.Although numerous studies on soybean unsaturated fatty acids have focused on the FAD2 gene，this gene accounts for only approximately 60% of observed genetic variation. Thus，identifying additional key loci governing UFA and selecting superior alleles remain crucial for developing functional soybean varieties.In this study，we quantified the contents of oleic acid，linoleic acid，and linolenic acid in 358 soybean germplasms and performed a genomewideassociation analysis using GEMMA's mixed linear model.Five significant loci that simultaneously regulate the threecomponents，along with two high-confidence loci（13-13101056 and14-46813345） significantly asociated with linolenic acid，were identified.Integrating linkage disequilibrium analysis and functional annotation，we identified GmFAD3A，a fatty acid desaturase gene，as a key regulator oflinolenic acid content. Haplotype analysis uncovered a non-synonymous mutation site（ 14⋅46811463C⋅r） in the third exon of GmFAD3A，defining two haplotypes， GmFAD3AT and GmFAD3Ac . Germplams carrying GmFAD3AT exhibited significantly lower linolenic acid but higher oleic acid levels compared to those carrying GmFAD3Ac The domestication analysis that the superior allele GmFAD3AT was prevalent in wild soybeans （95.5% ），landraces （ 85.6% ），and improved cultivars（ （91.7%） .This study provides a reliable theoretical basis for optimizing soybean UFA composition and ofers important loci and candidate genes for cultivating low linolenic acid，high oleic acid soybean varieties with an ideal ratio of unsaturated fatty acids.

Key words： soybean; unsaturated faty acids;genome-wide association analysis; GmFAD3A;functional locus

大豆（GlycinemaxL.Merr.）是全球重要的粮油和饲料作物[1，不仅为人类提供丰富的蛋白质和油脂，也为动物提供必要的营养[2-3]。（剩余18697字）