记者从中国农科院植物保护研究所获悉，中国工程院院士吴孔明领导的团队和英国兰开斯特大学合作，发现了一种对寄主棉铃虫有利的浓核病毒（HaDNV-1）。该病毒不但使棉铃虫幼虫更健康，还可提高其对生物杀虫剂的抗性水平。相关成果日前发表于《科学公共图书馆·病原体》杂志。
研究表明，棉铃虫感染该病毒后，幼虫和蛹的发育进度加快，成虫繁殖能力增强，对棉铃虫核型多角体病毒和Bt毒素的抗性提高。2008～2012年对不同地区棉铃虫自然种群的取样检测结果显示，接近80%的野生棉铃虫个体已携带HaDNV-1。
在生产中，Bt转基因抗虫作物和生物农药（棉铃虫核型多角体病毒等）是控制棉铃虫发生危害的主要手段。而HaDNV-1帮助棉铃虫发育得更健康，并提升其对Bt作物与生物杀虫剂的抗性。
相关专家表示，该成果增加了对昆虫—病毒关系的新认识，对深入揭示农业生态系统物种关系协同进化机制、发展害虫防治新理论和新方法有重要意义。
（来源：中国科学报 黄明明 孙爻）
Abstract:
Mutualistic associations between symbiotic bacteria and their hosts are common within insect systems. However, viruses are often considered as pathogens even though some have been reported to be beneficial to their hosts. Herein, we report a novel densovirus, Helicoverpa armigera densovirus-1 (HaDNV-1) that appears to be beneficial to its host. HaDNV-1 was found to be widespread in wild populations of H. armigera adults (>67% prevalence between 2008 and 2012). In wild larval populations, there was a clear negative interaction between HaDNV-1 andH. armigera nucleopolyhedrovirus (HaNPV), a baculovirus that is widely used as a biopesticide. Laboratory bioassays revealed that larvae hosting HaDNV-1 had significantly enhanced resistance to HaNPV (and lower viral loads), and that resistance to Bacillus thuringiensis (Bt) toxin was also higher at low doses. Laboratory assays indicated that the virus was mainly distributed in the fat body, and could be both horizontally- and vertically-transmitted, though the former occurred only at large challenge doses. Densovirus-positive individuals developed more quickly and had higher fecundity than uninfected insects. We found no evidence for a negative effect of HaDNV-1 infection on H. armigera fitness-related traits, strongly suggesting a mutualistic interaction between the cotton bollworm and its densovirus.
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