Bt稻Cry1Ab蛋白的表达和降解及对采后季节土表灰橄榄长角跳虫发生的影响

Expression and degradation of Cry1Ab protein in Bt hybrid rice and its impacts on ground-dwelling Entomobrya griseoolivata occurrence in postharvest seasons

Bt水稻及其植株残体中的Bt杀虫蛋白对土壤跳虫具有潜在的生态风险。作者以Bt杂交稻东龙(DL)及非亲本对照汕优46(XY)和西农优1号(XN)为材料,采用ELISA法分析了DL各植株组织中Cry1Ab蛋白的田间表达和采后残留,并评价了采后季节DL植株秸秆还田对稻田土表跳虫发生量的影响。结果表明,在测定的各生长阶段,DLCry1Ab在叶、茎和根系中的表达量为2.49～16.13μg/gFW;在采后季节,DL各秸秆还田植株残体中的Cry1Ab可残留较长时间,在试验第132天地表茎叶、稻桩和根系中的残留量分别为0.072、0.074和0.033μg/gDW;DL秸秆还田未对采后季节稻田土表发生量大的灰橄榄长角跳虫Entomobrya griseoolivata(Packard)种群数量产生显著影响,该跳虫种群密度动态在DL与对照XY和XN稻田基本相似,多数调查日期发生量无显著差异。

To assess the potential ecological risk of Bt rice plant straw returning to field on nontarget ground-dwelling springtails in postharvest seasons, field expression and postharvest degradation of Cryl Ab protein in Bt hybrid rice Donglong （DL） were determined by using standard ELISA test kits of US EPA. At the same time, the individual numbers of the predominant springtail Entomobrya griseoolivata （ Packard） （Collembola： Entomobryidae） were compared between DL and their non-parental control rice lines Xianyou 46 （XY） or Xinongyou 1 （XN） in postharvest paddy fields. Results showed that the Cryl Ab concentrations in the leaf blades, stems and roots of DL were 2.49 - 16.13 μg/g fresh weight in different developmental stages. The Cryl Ab could persist in DL plant litters for a long term after rice straw returning-to-field in postharvest seasons, and the CrylAb concentrations of the ground litters of stem and leaf, the rice plant stubbles and the root litters were 0. 072, 0. 074 and 0. 033 μg/g dry weight at 132 day, respectively. The population densities of E. griseoolivata between DL and XY or XN fields were not significantly different, and the population dynamics of E. griseoolivata in DL field is similar to the two controls in most cases.