绿豆醛酮还原酶基因及其响应镉胁迫的分析

Analysis of Aldo-keto Reductase Genes in Vigna radiata and Its Response to Cadmium Stress

基于绿豆基因组注释文件鉴定醛酮还原酶基因(AKRs),并采用生物信息学方法分析了绿豆AKRs基因结构及其编码的蛋白质序列特性;运用转录组和酶学方法分析Cd胁迫下绿豆幼苗根、茎和叶中AKRs基因的表达量和AKR酶活性的变化.结果表明:绿豆基因组含有9个AKRs基因,依次命名为VrAKR1.1~VrAKR1.5、VrAKR2及VrAKA1.1~VrAKA1.3;9个VrAKRs中分别含4~7个内含子和5~7个外显子.9个VrAKRs编码的蛋白质序列中,除VrAKA1.1、VrAKA1.2、VrAKA1.3外,其余VrAKRs均含有8个motif.9个VrAKRs的相对分子量29.1~39.0 kD,等电点pI 5.14~6.81,氨基酸残基数259~346,亲水性系数-0.304~-0.123;9个VrAKRs均含有Aldo_ket_red结构域.表达谱及酶活分析表明,VrAKA1.1、VrAKA1.2、VrAKA1.3基因在绿豆3个组织中均未表达,其余6个AtAKRs基因均表达了,但因组织和生长时间不同而异;根和茎表达量最高的基因均为VrAKR1.5,叶中则是VrAKR2.较对照比,Cd胁迫显著(p<0.05)上调了多数AtAKRs基因的表达水平,并显著(p<0.05)升高了AKR酶活性.综上所述,绿豆幼苗根、茎、叶中VrAKRs基因的表达存在组织特异性;胁迫下AKR酶活的变化受到VrAKRs基因表达程度的影响.表明绿豆幼苗期这些VrAKRs基因在响应Cd胁迫过程中发挥重要作用.

Aldo-keto reductase genes(AKRs) were identified based on the genome annotation file of Vigna radiata,and the genetic structures of AKRs of V.radiata and the physicochemical properties of their encoded protein sequences were analyzed by using bioinformatics method;the changes of expression levels of AKRs and activities of AKR enzyme in roots, stems, and leaves of V.radiata seedlings under Cd stress condition were analyzed by using transcriptome and enzymology methods.The results show that there are 9 AKRs in V.radiata genome, which are named as VrAKR1.1 to VrAKR1.5,VrAKR2 and VrAKA1.1 to VrAKA1.3 in sequence;9 VrAKRscontain 4~7 introns and 5~7 exons.Among the protein sequences of 9 VrAKRs, all VrAKRs except VrAKA1.1 to VrAKA1.3 contain 8 motifs.The relative molecular masses of 9 VrAKRs are 29.1~39.0 kD,the isoelectric points are pI 5.14~6.81,the number of amino acid residues are 259~346,and the hydrophilic coefficients are-0.304~-0.123.9 VrAKRs all contain Aldo_ket_red domain.The analysis results of expression profile and enzyme activities show that VrAKA1.1,VrAKA1.2 and VrAKA1.3 are not expressed in 3 organs of V.radiata,while the other VrAKRs are all expressed, but they varied with different organs and growth time;genes with the highest relative expression levels in roots, stems are VrAKR1.5 while in leaves is VrAKR2.Compared with the controls, Cd-treated significantly(p<0.05) up-regulated the expression levels of most VrAKRs, and significantly(p<0.05)increased AKR enzyme activities.The expression of VrADHs in roots, stems, and leaves of V.radiata seedlings show tissue specificity;the change of activity of AKR enzyme of V.radiata seedlings after Cd stress treatment is related to the expression level of some VrAKRs, suggesting that these VrAKRs genes are involved in the response process of V. radiata to Cd stress.