大气CO_2浓度升高对转基因玉米Bt毒素表达量的影响

Effects of elevated atmospheric CO_2 concentration on the expression of Bt toxin in transgenic maize

大气CO_2浓度升高不仅影响植物营养化学成分的变化,还能够引起植物次生抗虫物质表达量的改变,进而影响作物-害虫的互作关系。本试验利用开顶式气室(OTC)和室内动态气室模拟当前和未来大气CO_2浓度(约390、550、750μL/L)环境,测定了不同大气CO_2浓度下普通玉米‘郑58’和转cry1Ac-m基因玉米的营养物质成分、转cry1Ac-m基因玉米Cry1Ac杀虫蛋白的含量,以及取食不同大气CO_2浓度环境下生长的‘郑58’或转cry1Ac-m基因玉米叶片的亚洲玉米螟Ostrinia furnacalis(Guenée)初孵幼虫死亡率。结果表明,与对照相比,高大气CO_2浓度(750μL/L)环境下生长的转基因和对照玉米叶片中淀粉、可溶性糖、非结构性碳(TNC)含量及TNC∶N都明显增加,而N含量差异不显著。对照玉米叶片的N含量显著高于转基因玉米,其他营养成分没有显著变化。随着大气CO_2浓度的升高,转基因玉米的Cry1Ac蛋白表达量有下降的趋势,但各处理间差异不显著。亚洲玉米螟取食生长在不同大气CO_2浓度环境下的‘郑58’或转cry1Ac-m基因玉米叶片48h后,死亡率没有显著差异;转cry1Ac-m基因玉米具有显著的杀虫效果。

Elevated CO2（eCO2）will generally lead to the change of chemical composition of plants.On the other hand,eCO2 may also mediate the changes in plant secondary metabolism,which will affect the plant-herbivore interaction.This research simulated the growth and development of the corn line‘Zheng 58＇and a line expressing Bt Cry1 Ac toxin（GM-line）,Ostrinia furnacalis and their interactions under ambient environment with two eCO2（about 390μL/L,550μL/L,750μL/L）with open top chambers（OTCs）and closed dynamic chambers（CDC）.Corn plant chemistry,especially the C and/or N contents as well as Cry1 Ac toxin were assessed.The results showed that the starch and soluble sugar content,TNC and TNC∶N were significantly increased in the plant tissues under eCO2（750μL/L）OTC,but the N contents in leaves were not significantly different among CO2 concentrations.However,the N content in leaves of‘Zheng 58＇was significantly higher than that in GM-line.Although the amount of Cry1 Ac toxin expressed in GM-line leaves declined along with the increase in atmospheric CO2 level,there was no significant difference among atmospheric CO2 treatments.eCO2 did not significantly affect the mortality of O.furnacalis in 48 h.The survival rate was significantly lower in GM-line.