大豆GmDGAT3基因的鉴定及表达分析

Identification and Expression Analysis of Soybean GmDGAT3 Genes

二酰甘油酰基转移酶(DGAT)催化生成三酰甘油(TAG),在细胞油脂合成及积累中起重要作用。以花生(Arachis hypogaea)AhDGAT3为索引序列,全基因组鉴定大豆GmDGAT3基因,并应用生物信息学工具分析GmDGAT3基因编码蛋白的高级结构、系统发育和理化性质以及基因表达特征,旨在鉴定大豆(Glycine max)GmDGAT3基因。结果表明,序列比对分析发现大豆基因组有2个DGAT3蛋白,命名为Gm DGAT3-1和Gm DGAT3-2,长度分别为327,338个氨基酸,相对分子量分别为34.73,35.88 ku,二者均定位于细胞质中,且均无跨膜结构,为水溶性酶蛋白。二级结构均由α-螺旋、β转角、无规则卷曲和直链延伸组成。三维模型分析结果显示,Gm DGAT3蛋白以同源二聚体行使生物学功能。系统发育分析结果表明,Gm DGAT3蛋白与花生DGAT3蛋白同源性较高,暗示其可能有共同的进化来源。表达谱分析结果揭示,在大豆根、茎、叶、花、荚和种子中,GmDGAT3-2表达量均高于GmDGAT3-1,尤以GmDGAT3-2在花中的表达量最高。大豆基因组包含2个结构完整和有表达活性的Gm DGAT3。研究结果可为进一步解析大豆种子TAG及油脂生物合成调控机制提供科学参考。

Diacylglycerol acyltransferase(DGAT) catalyzes formation of triacylglycerol(TAG), functioning importantly in oil biosynthesis and accumulation. This study was to identify soybean (Glycine max) GmDGAT3 genes. Genome-wide identification for soybean GmDGAT3 genes was conducted using peanut(Arachis hypogaea) AhDGAT3 as the query sequence. Bioinformatics tools were employed to predict the high structure, physiochemical properties, and phylogeny of GmDGAT3 proteins. Moreover, qRT-PCR was perfomrd to exmine the expression profiles of GmDGAT3s in various soybean tissues. The result showed that two soybean GmDGAT3s namely GmDGAT3-1(327 aa, 34.73 ku) and GmDGAT3-2(338 aa, 35.88 ku) were identified from soybean genome by BLAST alignment. The two GmDGAT3s were predicted to be soluble enzymatic proteins without transmembrance domains, and to be located in cytosol. The second structure of GmDGAT3s mainly consisted of α-helix,β-sheet, random coil and linear extension. GmDGAT3s could form a homodimer to perform its biological functions revealed by 3D modeling. Phylogenetic analysis indicated that GmDGAT3 proteins had high homology with peanut DGAT3 protein, suggesting that they might have a common evolutionary source. The expression profiles demonstrated that GmDGAT3-2 transcript was higher than GmDGAT3-1 in soybean roots, stems, leaves, flowers, pods and seeds, with the highest expression of GmDGAT3-2 in flower. Soybean genome contains two GmDGATs with structural integrity and expression activity. The present data obtained here provide a scientific basis for further understanding oil biosynthesis and its regulationary mechanism in soybean seeds.