大豆膨胀素基因GmEXPB5和GmEXPB7生物信息学及表达分析

Bioinformatics and expression analysis of expansin genes GmEXPB5 and GmEXPB7 in soybean

关键词:  大豆, 膨胀素, 生物信息学分析, 非生物胁迫, 表达分析

Key words:  soybean(Glycine max), expansin, bioinformatics analysis, abiotic stress, expression analysis

摘要:

膨胀素(expansin,EXP)通过调控细胞壁的松弛在植物应对环境胁迫过程中起着重要作用。为研究EXP基因在大豆应对非生物胁迫过程中的作用,该文对大豆中的两个EXP基因(GmEXPB5和GmEXPB7)及其蛋白序列进行生物信息学分析,通过实时荧光定量PCR(qRT-PCR)检测基因表达量。结果表明:(1)GmEXPB5和GmEXPB7分别位于大豆第10号和第12号染色体上,编码的蛋白序列长度分别为272和267个氨基酸。GmEXPB5蛋白分子量为29.07 kD,理论等电点为7.51; GmEXPB7蛋白分子量为29.09 kD,理论等电点为8.66。GmEXPB5和GmEXPB7均为稳定的亲水蛋白且定位于细胞壁中。GmEXPB5和GmEXPB7蛋白均含有一段信号肽序列和一个保守的DPBB_1结构域。(2)GmEXPB5蛋白与鹰嘴豆CaEXPB15蛋白亲缘关系最近,GmEXPB7蛋白与密花豆、赤豆和豇豆的EXPB3蛋白有着较近的亲缘关系。(3)GmEXPB5和GmEXPB7在大豆根、茎和叶中均有表达且它们在根和叶中的表达量均显著高于茎中的表达量。(4)GmEXPB5和GmEXPB7在大豆幼苗中可以响应盐、干旱和低温胁迫。(5)GmEXPB5启动子区域含有2种与逆境相关的顺式作用元件(ABRE和ARE); GmEXPB7启动子区域含有5种与逆境相关的顺式作用元件(ABRE、ARE、CGTCA-motif、TC-rich repeats和MBS)。综上所述,GmEXPB5和GmEXPB7能够参与大豆对非生物胁迫的应答。

Abstract:

Expansin(EXP)plays an important role in plant response to environmental stress by regulating cell wall relaxation. To explore the role of EXP genes in soybean response to abiotic stress, two soybean EXP genes(GmEXPB5 and GmEXPB7)and their protein sequences were analyzed by bioinformatics, and their expression levels were detected by real-time fluorescent quantitative PCR(qRT-PCR). The results were as follows:(1)The GmEXPB5 and GmEXPB7 were located on chromosomes 10 and 12 of soybean, and encoded proteins containing 272 and 267 amino acids, respectively. The molecular weight of GmEXPB5 protein was 29.07 kD and the theoretical isoelectric point was 7.51. The molecular weight of GmEXPB7 protein was 29.09 kD and the theoretical isoelectric point was 8.66. Both GmEXPB5 and GmEXPB7 were stable hydrophilic proteins, and localized in the cell wall. Both GmEXPB5 and GmEXPB7 proteins contained a signal peptide sequence and a conserved DPBB_1 structural domain.(2)GmEXPB5 protein had the closest affinity with CaEXPB15 protein of Cicer arietinum, and GmEXPB7 protein was closely related to EXPB3 proteins of Spatholobus suberectus, Vigna angularis and V. unguiculata.(3)GmEXPB5 and GmEXPB7 were expressed in root, stem and leaf of soybean, and their expression levels in root and leaf were significantly higher than those in stem.(4)GmEXPB5 and GmEXPB7 could respond to salt, drought and cold stresses in soybean seedlings.(5)The promoter region of GmEXPB5 contained two types of stress-related cis-elements(ABRE and ARE). The promoter region of GmEXPB7 contained five types of stress-related cis-elements(ABRE, ARE, CGTCA-motif, TC-rich repeats and MBS). In conclusion, these results indicate that GmEXPB5 and GmEXPB7 can participate in the response of soybean to abiotic stress.