Abstract：
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.
摘要：
在中国已经开发了基因工程（GE）水稻系，该水稻系表达了苏云金芽孢杆菌（Bt）的鳞翅目活性杀虫cry基因。实地调查表明，尽管稻飞虱对所产生的BtCry蛋白不敏感，但Bt水稻的稻飞虱比非Bt水稻少。这种现象的潜在机制仍然未知。这里,我们表明，Bt水稻上的飞虱数量少与毛虫伤害减少有关。在实验室和田间试验中，稻飞虱Nilapavatalugens对未受损的Bt或非Bt植物没有摄食偏好，但对Bt或非Bt的毛虫受损植物表现出强烈的偏好。在野外条件下，在毛虫受损的非Bt水稻上，稻飞虱比在邻近的健康Bt水稻上更丰富。GC-MS分析表明，毛毛虫的伤害诱导了已知对飞虱有吸引力的水稻植物挥发物的释放，代谢组分析表明，氨基酸含量增加，固醇含量降低，已知有利于飞虱发育。因此，鳞翅目抗性Bt水稻对田间这种重要的非目标害虫的吸引力较小，这是Bt植物对非目标害虫的生态抗性的第一个例子。我们的发现表明，为延迟Bt抗性发展而建立的非Bt水稻避难所也可能充当N.lugens和其他飞虱的诱捕作物。
