抑制番茄叶绿体DnaJ蛋白基因的表达降低转基因番茄的抗高温能力

DnaJ蛋白是广泛存在于植物细胞内的一种分子伴侣。在胁迫条件下它能够保护细胞内蛋白质等结构的稳定性。本研究克隆到一个番茄叶绿体DnaJ蛋白基（LeCDJI）。半定量PcR分析表明LeCDJ1，的表达受NaCl、高温、PEGTLABA的诱导。利用反义抑制的方法获得了LeCDJl抑制表达的转基因番茄。高温条件下，转基因株系较野生型表现出较严重的光系统II（PsII）光抑制，较低的D1蛋白含量，较高的超氧阴离子（O2-）、过氧化氢（H2O2）含量，及较低的抗坏血酸过氧化物酶（APX）和超氧化物歧化酶（SOD）活性。这些结果表明，抑制LeCDJ1的表达降低了转基因番茄的抗高温能力。

Suppression of a Tomato Chloroplast DnaJ Protein Gene Reduced Heat Tolerance in Transgenic Tomatoes

DnaJ proteins are ubiquitous molecular chaperones contributing to cellular protein conformation stability under stress conditions. In this study, the full length of a tomato chloroplast DnaJ protein gene （LeCDJ1） was cloned and analyzed. The LeCDJ1 expression was up-regulated by NaCl, heat, PEG and ABA. Antisense-mediated suppression of LeCDJ1 transgenic tomato was obtained. The transgenic tomato showed more serious PSII photoinhibition, less D1 protein content, higher superoxide radical （O2-）and hydrogen peroxide （H202） content and lower scorbate peroxidase （APX） and superoxide dismutase （SOD） activity than WT under heat stress. These results indicated that LeCDJ1 suppression reduced heat tolerance in transgenic tomatoes.