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谷胱甘肽转移酶(Glutathione S-transferases,GSTs,EC 2.5.1.18)是生物体内重要的一种解毒和抗氧化酶类。为进一步研究该酶在木榄适应盐生环境中的作用,从前期构建的木榄幼叶cDNA文库中克隆到编码theta型GST(BgGSTT)的cDNA全序列,分析和预测了其编码产物的结构特征,探讨了该基因在不同盐度下生长的木榄幼苗叶片及根中的表达变化。结果发现:编码BgGSTT的cDNA全长1111 bp,编码区为753 bp,编码的蛋白由250个氨基酸残基组成,理论相对分子质量为28.1k,pI为9.42。系统发育分析显示BgGSTT与来源于拟南芥和乳浆大戟的GSTT同源性较高(identity分别为72%和65%)。利用荧光实时定量RT-PCR检测了BgGSTT在不同盐度下生长的木榄幼苗叶片及根中的表达变化,结果发现BgGSTT基因在木榄幼苗叶片中表达量较高,并且随着培养盐度的升高其表达逐渐加强,在25‰盐度达到最高,随后稍有下降但仍维持在较高水平。根据上述结果,推测BgGSTT基因可能参与了木榄适应盐胁迫的过程,并且该基因的表达在木榄幼苗叶片和根中具有严格的转录调控机制。
Glutathione S-transferases (GSTs, EC 2.5.1.18) are important detoxification and antioxidant enzymes in the body. In order to further study the role of this enzyme in the adaptation of Salvia miltiorrhiza to salt-tolerant environments, a full-length cDNA sequence encoding theta GST (BgGSTT) was cloned from the cDNA library of Oldenlandia miltiorrhiza. The structure of its coding product was analyzed and predicted The changes of the expression of this gene in the leaves and roots of M. bungeana seedlings grown at different salinities were investigated. The results showed that the full-length cDNA encoding BgGSTT was 1111 bp with a coding region of 753 bp. The encoded protein consisted of 250 amino acid residues with a theoretical relative molecular mass of 28.1 k and a pI of 9.42. Phylogenetic analysis showed that the homology of BgGSTT to GSTT from Arabidopsis thaliana and Euphorbia pulcherrima was high (identities of 72% and 65%, respectively). The changes of BgGSTT gene expression in leaves and roots of M. gramineus seedlings under different salinities were detected by real-time fluorescence quantitative RT-PCR. The results showed that the expression of BgGSTT gene was higher in leaves of M. bungeana seedlings, Increasing its expression gradually strengthened at 25 ‰ salinity reached its highest, then slightly decreased but still maintained at a high level. Based on the above results, it is speculated that BgGSTT gene may be involved in the process of Radix salivarius adaptation to salt stress, and the expression of this gene has a strict transcriptional regulation mechanism in the leaves and roots of M. bungeana seedlings.