烟草谷胱甘肽转移酶基因NtGSTU17的鉴定及表达特性分析

Identification and expression analysis of a tobacco glutathione transferase gene NtGSTU17

为研究烟草谷胱甘肽转移酶(GSTs)的功能,采用同源搜索的方法从NCBI数据库中找到1个烟草GSTs类似基因,通过聚类分析、体外活性分析对该基因及其表达产物进行鉴定;打顶和农药(代森锰锌、百草枯)处理烟草后,运用荧光实时定量PCR技术对该基因的表达特性进行分析。结果表明:该基因是tau类GST基因,命名为Nt GSTU17,其编码区长666 bp,编码221个氨基酸;该基因编码产物对谷胱甘肽转移酶通用底物1-氯-2,4-二硝基苯(1-Chloro-2,4-dinitrobenzene,CDNB)具有较高的偶联活性;Nt GSTU17基因在烟草中为组成型表达,但在根中的表达量要低于地上部分的表达量;打顶对该基因的表达有一定上调效应;代森锰锌处理烟草后在短期内能快速、显著上调Nt GSTU17基因的表达,而百草枯处理烟草后则能显著抑制根中Nt GSTU17的表达,表明Nt GSTU17基因可能参与烟草的胁迫应答反应,并对不同农药的胁迫表现出选择性。

To understand the function of tobacco glutathione transferases, a tobacco GST of tau class, previously known as NtParC, was identified by cluster analysis, and its protein activity was analyzed in vitro as well. The gene expression pattern under the treatment of topping, paraquat and mancozeb, was also investigated by qRT-PCR. The results showed that the tau class gene, renamed as NtGSTU17, was 666 bp in length, encoding 221 amino acids, which exhibited higher CDNB conjugation activity. NtGSTU17 was constitutively expressed in tobacco, while the expression level in root was a little bit lower than the level in aerial part of tobacco. Topping could increase NtGSTU17 expression. Mancozeb spraying significantly up-regulated the expression level of NtGSTU17 in a quick way both in root and leaf, in comparison with the significantly down-regulation effect of paraquat on the root. Therefore, NtGSTU17 might be involved in the tobacco stress response, and showed selectivity to different herbicides.