Rapid spread of a densovirus in a major crop pest following wide-scale adoption of Bt-cotton in China
Yutao Xiao, Wenjing Li, Xianming Yang, Pengjun Xu, Minghui Jin, He Yuan, Weigang Zheng, Mario Soberón, Alejandra Bravo, Kenneth Wilson, Kongming Wu
近日，中国农业科学院植物保护研究所科研团队联合中国农科院深圳基因组所、英国兰卡斯特大学等单位，在昆虫与共生微生物互作领域研究中取得重要进展。相关成果在线发表于国际期刊elife。
Bt棉花在中国有着20多年的种植历史，该作物种植结构的变化对靶标害虫、非靶标害虫、天敌昆虫、共生微生物的影响是非常重要的科学问题。
研究发现，一种共生病毒HaDV2在Bt棉的靶标害虫棉铃虫中广泛存在，且可以通过调控棉铃虫免疫通路相关基因，使其获得较高的适合度及Bt耐性能力。
十多年的田间调查和统计发现，Bt棉花的种植加速了棉铃虫HaDV2的感染。这表明在应对Bt棉花这一重大生存威胁时，棉铃虫不仅可以通过种群基因的变化产生适应性，同时可以借助微生物进行有效抵御。
该研究得到国家转基因专项的支持。
来源：中国科学报 李晨
Abstract
Bacillus thuringiensis (Bt) crops have been widely planted and the effects of Bt-crops on populations of the target and non-target insect pests have been well studied. However, the effects of Bt-crops exposure on microorganisms that interact with crop pests have not previously been quantified. Here, we use laboratory and field data to show that infection of Helicoverpa armigera with a densovirus (HaDV2) is associated with its enhanced growth and tolerance to Bt-cotton. Moreover, field monitoring showed a much higher incidence of cotton bollworm infection with HaDV2 in regions cultivated with Bt-cotton than in regions without it, with the rate of densovirus infection increasing with increasing use of Bt-cotton. RNA-seq suggested tolerance to both baculovirus and Cry1Ac were enhanced via the immune-related pathways. These findings suggest that exposure to Bt-crops has selected for beneficial interactions between the target pest and a mutualistic microorganism that enhances its performance on Bt-crops under field conditions.
