State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Research Division Agroecology and Environment, Agroscope, Zurich, Switzerland.
Plant Biotechnol J. 2018 Oct;16(10):1748-1755. doi: 10.1111/pbi.12911. Epub 2018 Apr 10.
Genetically engineered (GE) rice lines expressing Lepidoptera-active insecticidal cry genes from the bacterium Bacillus thuringiensis (Bt) have been developed in China. Field surveys indicated that Bt rice harbours fewer rice planthoppers than non-Bt rice although planthoppers are not sensitive to the produced Bt Cry proteins. The mechanisms underlying this phenomenon remain unknown. Here, we show that the low numbers of planthoppers on Bt rice are associated with reduced caterpillar damage. In laboratory and field-cage experiments, the rice planthopper Nilapavata lugens had no feeding preference for undamaged Bt or non-Bt plants but exhibited a strong preference for caterpillar-damaged plants whether Bt or non-Bt. Under open-field conditions, rice planthoppers were more abundant on caterpillar-damaged non-Bt rice than on neighbouring healthy Bt rice. GC-MS analyses showed that caterpillar damage induced the release of rice plant volatiles known to be attractive to planthoppers, and metabolome analyses revealed increased amino acid contents and reduced sterol contents known to benefit planthopper development. That Lepidoptera-resistant Bt rice is less attractive to this important nontarget pest in the field is therefore a first example of ecological resistance of Bt plants to nontarget pests. Our findings suggest that non-Bt rice refuges established for delaying the development of Bt resistance may also act as a trap crop for N. lugens and possibly other planthoppers.
中国已开发出表达苏云金芽孢杆菌（Bt）杀虫晶体蛋白基因的转基因（GE）水稻品系。田间调查表明，Bt 水稻上的稻飞虱数量比非 Bt 水稻少，尽管稻飞虱对产生的 Bt Cry 蛋白不敏感。这一现象的机制尚不清楚。在这里，我们表明 Bt 水稻上较少的飞虱数量与减少的幼虫损害有关。在实验室和田间笼实验中，白背飞虱 Nilapavata lugens 对未受损的 Bt 或非 Bt 植物没有摄食偏好，但对 Bt 或非 Bt 的受损植物表现出强烈的偏好。在野外条件下，受损幼虫的非 Bt 水稻上的稻飞虱比邻近健康的 Bt 水稻上更为丰富。GC-MS 分析表明，幼虫损伤诱导了已知对飞虱有吸引力的水稻植物挥发物的释放，代谢组分析显示，已知有利于飞虱发育的氨基酸含量增加，固醇含量降低。因此，对这种重要的非靶标害虫具有鳞翅目抗性的 Bt 水稻在田间的吸引力降低是 Bt 植物对非靶标害虫的生态抗性的第一个例子。我们的研究结果表明，为了延缓 Bt 抗性的发展而建立的非 Bt 水稻避难所也可能成为 N. lugens 和可能其他飞虱的诱捕作物。
