转Bt-Cry1Ac基因棉花对烟粉虱体内几种酶活力的影响

为研究转Bt基因棉花上烟粉虱种群较常规棉上升的原因是否受到Bt毒蛋白的影响,以及是否与体内保护酶和解毒酶活力变化有关,应用转Bt基因棉花‘新棉33B’及其常规棉受体‘33’为试验对象,采用ELISA法和酶活力测定法,分别研究了取食转Bt基因棉花后烟粉虱体内Bt毒蛋白含量以及体内过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)3种保护酶和乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽-S-转移酶(GSTs)3种解毒酶活力的变化情况。结果表明,在取食转Bt基因棉花‘新棉33B’4 h后,烟粉虱体内能检测到Cry1Ac蛋白,并且在12 h后维持在一个相对稳定的状态。取食‘新棉33B’后烟粉虱体内的SOD和GSTs活力受到显著抑制(P0.05),并且随着取食时间的延长,SOD活力逐渐下降,其中取食8 h、12 h、24 h和36 h后较取食‘33’的对照分别下降了37.8%、32.1%、32.0%和31.9%。CAT、POD和CarE活力显著提高(P0.05),并且随着取食时间的延长,酶活力逐渐上升,与对照相比,取食12 h、24 h和36 h后,CAT活力分别为取食‘33’的对照的1.54倍、1.55倍和1.42倍;POD活力分别为取食‘33’的对照的1.59倍、1.39倍和1.53倍;CarE活力分别为取食‘33’的对照的1.32倍、1.34倍和1.39倍;取食‘新棉33B’对AChE活力没有明显影响。结果提示,转Bt-Cry1Ac基因棉花对烟粉虱保护酶活力总体起到促进作用,对解毒酶活力总体影响不大。故烟粉虱体内保护酶活力的增加可能会有益于烟粉虱种群的增长,但是否起到决定性作用还有待进一步研究确定。

Effects of transgenic Bt-Cry1Ac cotton on activities of Bemisia tabaci enzymes

To determine whether Bemisia tabaci population in transgenic Bt cotton exceeded that in conventional cotton and driven by Bt toxalbumin, and whether this was related to the change in the activity of protective enzymes and detoxification enzymes in B. tabaci, the study used transgenic Bt cotton 'Xinmian33B' and the conventional parental cotton '33' for the case study, and used the ELISA method and enzyme activity determination method to separately analyze Bt toxalbumin content, changes of activities of SOD, CAT and POD protective enzymes and of AChE, CarE and GSTs detoxification enzymes after B. tabaci feeding on transgenic Bt cotton. The results showed that Cry1Ac protein was detectable in B. tabaci after fed for 4 h on transgenic Bt cotton 'Xinmian33B', getting relatively stable after 12 h. The activities of SOD and GSTs were significantly inhibited (P < 0.05) after B. tabaci fed on 'Xinmian33B'. SOD activity steadily declined with the extension of the feeding time, declining 37.8%, 32.1%, 32.0% and 31.9% after feeding for 8 h, 12 h, 24 h and 36 h, respectively. Meanwhile, the activities of CAT, POD and CarE increased significantly (P < 0.05) and the enzyme activity steadily increased with the extension of feeding time. CAT activity was respectively 1.54 times, 1.55 times and 1.42 times; POD activity 1.59 times, 1.39 times and 1.53 times; and CarE activity 1.32 times, 1.34 times and 1.39 times those of the control after feeding for 12 h, 24 h and 36 h. The activity of AChE was not significantly affected after feeding on 'Xinmian33B'. These results suggested that the activities of protective enzymes of B. tabaci increased overall. The activities of detoxification enzymes were significantly affected by transgenic Bt-Cry1Ac cotton. Thus the addition of protective enzyme activity to B. tabaci could increase B. tabaci population. Further study was recommended to determine whether or not this effect was conclusive.