马铃薯StTrxF基因的克隆与功能分析

为探究马铃薯硫氧还蛋白基因(StTrxF)的耐盐生理机制,通过RT-PCR方法从马铃薯品种中薯5号中克隆得到全长549bp硫氧还蛋白基因(StTrxF)。该基因编码182个氨基酸,预测蛋白质分子量为44.17ku,理论等电点(pI)为5.23,具有典型的Thioredoxin结构域。由StTrxF基因推导的氨基酸序列与番茄、拟南芥、芝麻和赤霞珠等TrxF蛋白质氨基酸序列的同源性为96.02%～59.28%。构建植物过表达载体,导入拟南芥中,获得转基因拟南芥纯系植株。通过对转基因拟南芥植株的耐盐离体和盆栽鉴定,表明转基因植株的耐盐性显著提高。同时盐胁迫下,转基因植株的超氧化物歧化酶(SOD)活性和脯氨酸含量显著提高,丙二醛(MDA)含量显著降低。结果表明,表达StTtxF基因通过增加转基因植株脯氨酸含量,提高SOD活性,降低MDA含量,以维持细胞渗透平衡并激活ROS清除系统,具有提高转基因拟南芥植株耐盐性的显著效果。

Cloning and function analysis of potato StTrxF gene

To explore the salt-tolerant physiological mechanism of potato thioredoxin gene (StTrxF), StTrxF gene was cloned from potato No. 5 by RT-PCR. The ORF of StTrxF was 549 bp in length and encoded 182 amino acids with a molecular weight of 44.17 ku and a theoretical isoelectric point (pI) of 5.23 with a typical thioredoxin domain. The amino acid sequence deduced from StTrxF gene was 96.02%-59.28% homology to the TrxF proteins of Arabidopsis thaliana, sesame and Cabernet sauvignon. A plant expression vector was constructed and the StTrxF gene was introduced into Arabidopsis by dipping method to obtain transgenic Arabidopsis homozygous lines. The salt tolerance of transgenic Arabidopsis plants was identified by pot experiment. The results indicated that the salt tolerance of transgenic plants was significantly improved. At the same time, under salt stress, the superoxide dismutase (SOD) activity and proline content were significantly increased, and the content of malondialdehyde (MDA) was significantly decreased. These results indicated that the expression of StTtxF gene had significant effect on enhancing the salt tolerance of transgenic Arabidopsis plants by increasing proline content and SOD activity, decreasing MDA content in the transgenic plants, maintaining cell osmotic balance and activating ROS scavenging system. This study would provide an experimental basis for further research of salt-tolerant crops, and a theoretical reference for plant salt-tolerant bio-genetic engineering.