关键词: 大豆, 鲜籽粒, 可溶性糖含量, 全基因组关联分析, SNP

Abstract: 【Objective】Soluble sugar content is one of the important quality traits of vegetable soybean. The genetic variation and genetic mechanism of soluble sugar content in fresh soybean seeds were studied to provide a basis for germplasm innovation and quality breeding of vegetable soybean. 【Method】Using 133 soybean landraces from the Northeast region, the North region, the Huanghuaihai region and the South region, the soluble sugar content of fresh seeds was determined in the three environments of Lianjiang in spring, Fuqing in spring and autumn, in 2021. In combination with 82 187 high-quality SNP markers, the whole genome association analysis of soluble sugar content was conducted based on the mixed linear model MLM (Q+K), and the SNP loci with significantly related to soluble sugar content were identified. The candidate intervals were selected by the significant SNP loci and the extension of 119.07 kb linkage disequilibrium decay distance at both ends. The candidate genes were predicted according to the annotation and tissue expression information of the genes in the candidate intervals. 【Result】The variation range of soluble sugar content in fresh seeds under three environments was 3.37-33.84 mg·g^-1, the genetic variation coefficient was 24.59%-32.69%, and the heritability of soluble sugar content was 68.14%. Six, eight and 22 SNPs were significantly associated with the soluble sugar content of fresh seeds were detected in Lianjiang in spring, Fuqing in spring and autumn, respectively, and phenotypic variation was 12.43%-29.27%. A total of 86 genes were obtained in the candidate regions of 9 significant SNP loci with higher interpretation rate of phenotypic variation, and 9 candidate genes were further screened by gene annotation and tissue expression information. These candidate genes are mainly involved in biological processes such as transcription factors, glycoprotein families and carbohydrate synthesis and transport. Among them, Glyma.01g016500, Glyma.13g042100, Glyma.16g131800 and Glyma.16g155300 were more highly expressed in soybean seeds and pods, which can be used as the most potential candidate genes for soluble sugar in fresh soybean seeds.【Conclusion】Through genome-wide association analysis, 36 SNPs significantly associated with soluble sugar content in fresh seeds were detected, and 9 candidate genes were further screened out, which may be involved in the regulation of soluble sugar content in fresh soybean seeds. Among them, Glyma.01g016500, Glyma.13g042100, Glyma.16g131800 and Glyma.16g155300 can be the key candidate genes for regulating soluble sugar content in fresh soybean seeds.

Key words: soybean, fresh seeds, soluble sugar contents, genome wide association analysis, SNP