大豆含硫氨基酸相关酶基因发掘

Gene mining of sulfur-containing amino acid metabolic enzymes in soybean

大豆（Glycine max）含硫氨基酸合成途径中的酶基因是含硫氨基酸组分的重要调控基因,发掘相关酶基因对高含硫氨基酸分子育种具有重要意义.文章采用大豆物理与遗传整合图谱,通过BioMercator2.1将113个含硫氨基酸合成途径酶基因及33个控制含硫氨基酸含量的QTL整合到遗传图谱Consensus Map 4.0上,依据酶基因位点与QTL的一致性以及QTL的效应值,初步筛选到16个与含硫氨基酸合成相关的候选基因.通过生物信息学方法对候选基因进行拷贝数、SNP、表达谱等分析,鉴定到12个相关酶基因,分别位于D1a、M、A2、K和G等8个连锁群上.生物信息学分析显示这些基因所在QTL可解释含硫氨基酸遗传变异的6.0％～38.5％,其中9个基因的间接效应值超过10％. 12个相关酶基因参与含硫氨基酸代谢的重要途径,且多在子叶、花中高丰度表达,存在丰富的SNP.这些基因可作为候选基因进行功能标记开发,将为大豆分子设计育种奠定基础.

The genes of sulfur-containing amino acid synthetases in soybean are essential for the synthesis of sulfur-containing amino acids.Gene mining of these enzymes is the basis for the molecular assistant breeding of high sulfur-containing amino acids in soybean.In this study,using software BioMercator2.1,113 genes of sulfur-containing amino acid enzymes and 33 QTLs controlling the sulfur-containing amino acids content were mapped onto Consensus Map 4.0,which was integrated by genetic and physical maps of soybean.Sixteen candidate genes associated to the synthesis of sulfur-containing amino acids were screened based on the synteny between gene loci and QTLs,and the effect values of QTLs.Through a bioinformatic analysis of the copy number,SNP information,and expression profile of candidate genes,12 related enzyme genes were identified and mapped on 8 linkage groups,such as Dla,M,A2,K,and G.The genes corresponding to QTL regions can explain 6%-38.5% genetic variation of sulfur-containing amino acids,and among them,the indirect effect values of 9 genes were more than 10%.These 12 genes were involved in sulfur-containing amino acid metabolism and were highly expressed in the cotyledons and flowers,showing an abundance of SNPs.These genes can be used as candidate genes for the development of functional markers,and it will lay a foundation for molecular design breeding in soybean.