Effects of Extreme Air Temperature and Humidity on the Insecticidal Expression Level of Bt Cotton
Effects of Extreme Air Temperature and Humidity on the Insecticidal Expression Level of Bt Cotton
复制标题
极端气温和湿度对Bt棉花杀虫表达水平的影响
DOI：
10.1016/s2095-3119(12)60188-9
复制
发表时间：
2012-01-01
影响因子：
4.8
通讯作者：
Chen De-hua
中科院分区：
文献类型：
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作者：
Chen Yuan;Wen Yu-jin;Chen De-hua
转基因苏云金芽孢杆菌（Bacillus thuringiensis, Bt）棉花在极端温度(T)和相对湿度（RH）胁迫的恶劣气候条件下，其幼虫存活率较高。Bt棉对棉铃虫的不稳定抗性与cryac δ内毒素表达减少有关。本研究旨在探讨温度和相对湿度联合胁迫对水稻关键发育阶段叶片cryac杀虫蛋白表达的影响。本研究于2007年和2008年两个具有相同亲本背景的转基因棉花品种——常规品种四康1号和杂交品种四康3号，在扬州大学农场进行。本研究采用温度（2个水平）和相对湿度（3个水平）两个因素进行布置。6种T/RH处理分别为37℃/95%、37℃/70%、37℃/50%、18℃/95%、18℃/70%和18℃/50%。2007年，6种处理分别施用于植株盛花期24 h；2008年，将6个处理分别施用于花期、花期和铃期，处理时间为48 h。研究结果表明，CryIAc叶片杀虫蛋白表达仅在花期和灌铃期受极端温度和相对湿度的显著影响。在铃期高峰施加应力时，观察到最大的降低。2008年，胁迫处理48 h后，四康1号和四康3号叶片Bt内毒素表达量在铃峰期分别降低了25.9 ~ 36.7%和23.6 ~ 40.5%，而在开花期分别仅降低了14.9 ~ 26.5和12.8 ~ 24.0%。在低温和低相对湿度条件下，两者的降幅最大。认为温度和相对湿度胁迫可能是Bt棉在中国生长条件下效能降低的原因，中国在棉花生长季节，极端温度经常上升到35-40℃，或下降到15-20℃，相对湿度可能达到85-95%和/或下降到40-55%。
The higher survival rates of Helicoverpa amigera larvae were usually observed after adverse climate which was related to extreme temperature (T) and relative humidity (RH) stresses in transgenic Bacillus thuringiensis (Bt) cotton. The unstable resistance of Bt cotton to bollworms has been correlated with the reduced expression of CryIAc delta-endotoxin. The objective of this study was to investigate the effects of combined temperature and relative humidity stresses on the leaf CryIAc insecticidal protein expression during critical developmental stages. The study was undertaken on two transgenic cotton cultivars that share same parental background, Sikang 1 (a conventional cultivar) and Sikang 3 (a hybrid cultivar), during the 2007 and 2008 growing seasons at the Yangzhou University Farm, Yangzhou, China. The study was arranged with two factors that consisted of temperature (two levels) and relative humidity (three levels). The six T/RH treatments were 37 degrees C/95%, 37 degrees C/70%, 37 degrees C/50%, 18 degrees C/95%, 18 degrees C/70%, and 18 degrees C/50%. In 2007, the six treatments were imposed to the plants at peak flowering stage for 24 h; in 2008, the six treatments were applied to the plants at peak square, peak flowering, and peak boll stages for 48 h. The results of the study indicated that the leaf insecticidal protein expression in CryIAc was significantly affected by extreme temperature only at peak flowering stage, and by both extreme temperature and relative humidity during boll filling stage. The greatest reductions were observed when the stresses were applied at peak boll stage. In 2008, after 48 h stress treatment, the leaf Bt endotoxin expression reduced by 25.9-36.7 and 23.6-40.5% at peak boll stage, but only by 14.9-26.5 and 12.8-24.0% at peak flowering stage for Sikang 1 and Sikang 3, respectively. The greatest reduction was found under the low temperature combined with low relative humidity condition for both years. It is believed that the temperature and relative humidity stresses may be attributed to the reduced efficacy of Bt cotton in growing conditions in China, where extreme temperatures often increase up to 35-40 degrees C and/or decrease down to 15-20 degrees C, and relative humidity may reach to 85-95% and/or reduce to 40-55% during the cotton growing season.