高温胁迫终止后Bt棉蕾杀虫蛋白的恢复特征及相关生理机制

以大面积生产应用的Bt棉常规种‘泗抗1号’和杂交种‘泗抗3号’为材料,于扬州大学遗传生理重点实验室人工气候室,以盆栽方式设计高温胁迫试验。2017年设蕾期38℃高温持续胁迫72h终止、2018年设38℃高温持续胁迫96 h终止处理后不同时间(0、12、24、48、72和96 h)研究棉蕾Bt杀虫蛋白表达量变化及相关氮代谢生理。结果表明,盛蕾期38℃持续胁迫72 h、96 h终止后棉蕾Bt杀虫蛋白表达量均能恢复到相应对照水平,并且恢复所需时间随胁迫持续时间的延长而增加。胁迫72 h终止后,常规种泗抗1号经72 h、杂交种泗抗3号经48h蕾的Bt杀虫蛋白表达量与对照已无显著差异;胁迫96 h终止后,泗抗1号经96 h、泗抗3号经72 h,棉蕾Bt杀虫蛋白表达量与对照已无显著差异。相关分析表明,高温胁迫终止后,蕾中可溶性蛋白表达量、谷氨酸丙酮酸转氨酶(GPT)活性、谷氨酸草酞乙酸转氨酶(GOT)活性与Bt杀虫蛋白表达量呈极显著正相关(相关系数分别为0.964**、0.981**、0.971**);而游离氨基酸含量、蛋白酶和肽酶的活性与Bt杀虫蛋白表达量呈极显著负相关(相关系数分别为-0.894**、-0.912**、-0.834**)。因此,生产上可根据高温持续时间预测棉蕾Bt杀虫蛋白表达量的恢复程度,合理防治棉铃虫等相关害虫。

Recovery characteristics of Bt insecticidal protein and relative physiological mechanisms after high temperature stress termination in square of Bt cotton

The experiments were conducted at Key Laboratory of Genetics and Physiology of Yangzhou University. The conventional cultivar Sikang-1 and hybrid cultivar Sikang-3 were used as the experimental materials. The potted cotton at squaring stage was moved to artificial climatic chamber with 38℃ for 72 h , and 38℃ for 96 h respectively in 2017 and 2018 cotton growth season, and moved to natural conditions, then the squares were collected to measure the Bt protein concentration and nitrogen metabolic physiology at 0, 12, 24, 48, 72, 96 hours respectively after the high temperature termination. The square Bt insecticidal protein contents were able to recover to the corresponding control level, the time for the recovery was in need of longer as the stressed high temperature period increased. In 72 h high temperature treatment, the square Bt insecticidal protein content could recover to the corresponding control level at 72 h for Sikang-1 and at 48 h for Sikang-3. In 96 h high temperature treatment, the square Bt insecticidal protein content could recover to the corresponding control level at 96 h for Sikang-1 and at 72 h for Sikang-3. There were significantly positive correlations of Bt toxin content with soluble protein content, glutamate pyruvate transaminase activity and glutamate oxaloacetate transaminase activity (the correlation coefficients were 0.964 ^**, 0.981 ^**, and 0.971 ^**, respectively), and significantly negative correlations of Bt toxin content with free amino acid contents, and activitied of protease and peptidase (the correlation coefficients were -0.894 ^**, -0.912 ^**, and -0.834 ^**, respectively). Therefore, the recovery degree of Bt insecticidal protein content of cotton square can be predicted according to the duration of high temperature stress, reasonably controlling Helicoverpa armigera and related pests in production.