ERsHSP的过量表达减缓番茄体内低温诱导的UPR应答

本文对过表达内质网小分子热激蛋白（ERsHSP）的转基因番茄植株进行了抗寒性和UPR应答分析。结果表明，同对照相比，过表达ERsHSP的转基因番茄具有较强的抗寒性，其冷害症状轻，叶绿素含量的损失少，体内积累的MDA含量少，电解质外渗程度低并具有较高的净光合速率；低温能够诱导番茄体内BiP和Calnexin mRNA表达量的增加，但相同胁迫条件下，转基因番茄中BiP和Calnexin mRNA的表达量显著低于对照；处理72h时，对照中BiP和Calnexin mRNA的表达量达到最高，随后开始下降，而转基因番茄中BiP和Calnexin mRNA的表达量呈稳定上升趋势。说明过表达ERsHSP能够减缓并维持低温胁迫下转基因番茄中的UPR应答，减轻低温诱导的ER胁迫。

Overexpression of Small Heat - Shock Protein of Endoplasmic Reticulum in Tomato Attenuates the Unfold Protein Response of Plant under Cold Stress

In this study, the ERsHSP over expressing transgenic tomato plants were used to analyze the cold -re- sistance ability and the UPR under cold stress. Compared with non -transgenic and pROK II -transformed tomato plants, transgenic tomato plants possessed higher cold - resistance ability which exhibited slighter cold - injured symptoms,less destruction of chlorophyll and electrolyte leakage, lower content of MDA and higher value of net photosynthetic rate. The results showed that the expression of BiP and Calnexin was up - regulated under cold stress. However, the mRNAs level of these two genes in transgenic tomato plants was dramatically lower than those in non- transgenic plants under the same stress conditions. In non -transgenic tomato plants, the induction of BiP and Calnexin expression peaked after cold stress treatment at 4~C for 72 h and declined thereafter. However, there was a steady and increasing expression of BiP and Calnexin in transgenic pla~ts. On the whole, these data suggest that overexpression of ERsHSP in transgenic tomato plants could alleviate and keep the UPR under cold stress, thus reduce the ER stress induced by cold stress.