大豆HMGR基因家族的鉴定与表达分析

Identification and expression analysis of HMGR gene family in Glycine max

[目的]3-羟基-3-甲基戊二酰辅酶A还原酶(HMGR)是大豆皂苷合成途径的关键酶之一。从全基因组水平鉴定大豆 HMGR 基因家族并进行生物信息学和表达模式分析,为研究和利用大豆 HMGR 基因家族生物学功能奠定基础。[方法]根据Pfam数据库中 HMGR 基因的保守结构域(编号PF00368),利用HMMER3.0、PFAM和SMART软件鉴定大豆基因组中的 HMGR 基因。采用ProtParam等软件对其基因和蛋白序列进行生物信息学分析。利用qRT-PCR方法分析 GmHMGR 基因在苗期根、茎、叶等不同组织中和籽粒不同发育时期的表达情况。[结果]大豆基因组中鉴定得到8个 GmHMGR 基因,分布于8条染色体上,编码80~608个氨基酸,相对分子质量介于8.23~64.96 kD,理论等电点变化为4.89~8.24,二级结构中α螺旋和无规则卷曲所占比重较大,具有保守的基因结构和蛋白功能域。qRT-PCR分析表明,相比于其它 GmHMGR 基因, GmHMGR6 在苗期根、茎、叶中高度表达,籽粒发育过程中 GmHMGR3 基因在开花后40 d表达水平最高,开花后70 d大豆的成熟籽粒中 GmHMGR6 的表达丰度最高。[结论]大豆基因组中含有8个 HMGR 基因,具有保守的功能结构域和基因结构。 GmHMGR 基因家族在苗期根、茎、叶及不同发育时期籽粒中具有多样化的组织表达模式和时空表达特征。

[Objective] 3-hydroxy-3-methylglutaryl-coenzyme Areductase (HMGR) is one of the key enzymes involvedin the soybean saponin biosynthesis. Present study was aimed to identify and analyze HMGR family genes in soybean on the whole genome level which could support the in-depth study and utilization of HMGR family genes in the soybean.[Methods] HMMER3.0, PFAM and SMART software were applied to identify HMGR gene in the soybean genome based on the conserved domain of the HMGR genes of the Pfam database (No. PF00368).Bioinformatics analysis of HMGR gene and protein sequences were conducted with ProtParam and other software. Quantitative real time PCR was used to analyze the relative expression of HMGR genes in roots, stems, leaves at seedling stage, and seeds at different developmental stages.[Results] A total of eight GmHMGR genes were identified which distributed in eight chromosomes. Proteins encodedby these genes contained 80~608 amino acids with the molecular weight ranged from 8.23~ 64.96 kD, and theoretical isoelectric point varied from 4.89~8.24. The main secondary structureof these proteins were α helix and random coils. Quantitative real time PCR analysisshowed that GmHMGR 6 was highly expressed in various tissues at seedling stage. GmHMGR 3 expressed at the highest level in 40 days after flowering, while GmHMGR 6 produced the highest gene expression level among all HMGR genes, and it was highly expressed in 70 days after flowering when seeds was at matured stage.[Conclusion] Eight HMGR genes existed in soybeans with conserved functional domains and gene structure. GmHMGR gene family owns diverse tissue and spatiotemporal expression characteristics.