太子参谷胱甘肽-S-转移酶基因家族 生物信息学及表达分析

Bioinformatics and expression analysis of glutathione-S-transferase gene family in Pseudostellaria heterophylla

关键词:  太子参,GSTs,基因家族,生物信息学分析,表达分析

Key words:  Pseudostellaria heterophylla, GSTs, gene family, bioinformatics analysis, expression analysis

摘要:

GSTs(glutathione-S-transferases)是一个普遍存在于植物体内,多基因家族编码的多功能蛋白酶。为研究GSTs基因家族在太子参中对其生长发育以及活性成分合成调控的潜在功能,该文基于隐马尔可夫模型在太子参中鉴定到30个谷胱甘肽-S-转移酶(PhGSTs)的基因家族成员。结果表明:30个PhGSTs基因同时具有高度保守的N-端结构域和复杂多变的C-端结构域,分属于6个亚家族,有10个motif区,其中motif1、motif2、motif3同属于所有家族,motif4仅属于Tua亚家族。PhGST蛋白质三级结构有明显的相似之处,N端主要由3个α螺旋和4个β折叠构成βαβαββα结构域,C端均由α螺旋构成,不同亚家族的C端α螺旋数目及组合方式各不相同,但始终维持相似的三维结构。PhGST基因在太子参植物中具有不同的组织表达特异性,PhGSTU1、PhGSTU8、PhGSTU9等在太子参块根中优势表达,PhGSTF2在茎和叶中优势表达。水分胁迫处理后有4个基因积极响应干旱胁迫,PhGSTZ1的响应最为明显;同时也有PhGSTU8、PhEFB1γ3等4个基因随土壤含水量增加呈上调表达。该文鉴定出30个PhGST基因,并分析了其在太子参中的表达模式,为PhGSTs基因家族在太子参活性成分的合成调控及逆境响应等生理过程中的功能研究奠定理论基础。

Abstract:

GSTs(glutathione-S-transferases)is a multi-functional protease commonly existing in plants and encoded by multi-gene family. In order to study the potential function of GSTs gene family in regulating the growth and development of Pseudostellaria heterophylla and the synthesis of active components, 30 glutathione-S-transferase(PhGSTs)gene family members were identified in P. heterophylla based on hidden Markov model. The results were as follows: 30 PhGSTs genes had both highly conserved N-terminal domain and complex and changeable C-terminal domain, which belonged to six subfamilies and ten motif regions, among which motif 1, motif 2 and motif 3 belonged to all families, motif 4 belonged only to Tua subfamily. There were obvious similarities in the tertiary structure of PhGST protein. The N-terminal mainly consisted of three α helices and four β folds to form βαβαββα domain. The C-terminal consisted of α helices. The number and combination of C-terminal α helices of different subfamilies were different, but the similar three-dimensional structure was always maintained. PhGST gene had different tissue expression specificities in P. heterophylla plants. For example, PhGSTU1, PhGSTU8, PhGSTU9 and other genes were preferentially expressed in the root tuber of P. heterophylla, and PhGSTF2 was preferentially expressed in stems and leaves. Four genes responded positively to drought stress after water stress treatment, and PhGSTZ1 showed the most obvious response. At the same time, four genes were up-regulated with the increase of soil water content, such as PhGSTU8 and PhEFB1γ3. In this paper, 30 PhGST genes were identified and their expression patterns in P. heterophylla were analyzed, which laid a theoretical foundation for the functional research of PhGSTs gene family in physiological processes such as synthesis regulation of active components in P. heterophylla and stress response.