氯虫苯甲酰胺调控小菜蛾性信息素生物合成的分子机制

The diamondback moth (DBM), Plutella xylostella, is one of the most economically important cruciferous pest insects in the world. Chlorantraniliprole is a novel diamide insecticides with high efficacy against lepidopterous pests, and become the main variety in the control of DBM. However, the over use of the insecticide not only lead to the development of serious insecticide resistance, but also show significant effect on the titre and main components ratios of sex pheromone, which have resulted in control failure of some commercial sex pheromone attractants. While the mechanisms of insecticides affecting the synthesis of sex pheromone is kept unknown. In the present study, we want to 1) investigate the effect of chlorantraniliprole stress on the courtship and mating behavior, and the sex pheromone titre and main components ratios; 2) screen the key genes which show significant response to chlorantraniliprole stress and verify their biological functions; 3) study the regulation mechanisms of these key genes at both the transcriptional and post-transcription levels. The objective of this project is to make clear the mechanisms of chlorantraniliprole affecting the synthesis of sex pheromone in DBM, and the results will be helpful for the improve of insecticide toxicology theory and management of chlorantraniliprole resistant DBM populations in field through rational use of sex pheromone attractants.

小菜蛾是十字花科蔬菜的重要害虫。氯虫苯甲酰胺是对鳞翅目害虫高效的新型杀虫剂，是国内外防治小菜蛾的主打品种。但杀虫药剂的长期过量使用不仅导致抗药性的产生，还会影响小菜蛾性信息素的滴度和主要成分比例的变化，严重影响性诱剂的田间防治效果。目前对于杀虫剂胁迫影响昆虫性信息素合成的机制缺乏研究。本项目拟以小菜蛾和氯虫苯甲酰胺为对象，1）研究氯虫苯甲酰胺胁迫对小菜蛾求偶行为、交配行为及性信息素滴度和主要组分比例的影响；2）筛选氯虫苯甲酰胺胁迫后小菜蛾性信息素合成通路中表达量变化显著的关键基因并验证其功能；3）从转录水平和转录后水平研究所筛选的性信息素合成通路中关键基因表达的调控机制。通过上述研究，阐明氯虫苯甲酰胺影响小菜蛾性信息素合成的分子机制。研究结果对于完善昆虫毒理学理论以及合理利用性诱剂控制氯虫苯甲酰胺抗性小菜蛾具有积极的理论和实践意义。

本项目以十字花科类作物重要害虫小菜蛾为对象，较为系统地研究了氯虫苯甲酰胺短期和长期胁迫对小菜蛾雌雄交配能力及求偶行为的影响及其分子机制。1）明确了氯虫苯甲酰胺短期胁迫和长期胁迫均可显著降低小菜蛾雌雄交配能力及雌蛾的求偶率；2）小菜蛾性信息素组分Z11-16:Ald在氯虫苯甲酰胺抗性品系中的滴度显著低于敏感品系；性信息素的两种主要组分（Z11-16:Ald/Zll-16:Ac）的总量在小菜蛾氯虫苯甲酰胺抗性品系中也显著低于敏感品系，且其比例也发生了明显变化，在敏感品系中为4:5，而抗性品系中则为5.2:10；3）氯虫苯甲酰胺通过抑制小菜蛾ACC酶基因的转录，干扰了脂肪酸前体的合成，从而抑制了雌性性信息素的合成；miR-2755-3p和miR-2767-5p可能参与了对ACC酶基因的转录后调控；4）氯虫苯甲酰胺通过直接与PxPBP1和PxPBP2结合并降低其表达量从而影响小菜蛾雄蛾的性信息素识别，小菜蛾对氯虫苯甲酰胺的抗性以雄蛾对性信息素的反应能力下降为代价。研究结果阐明了氯虫苯甲酰长期胁迫影响小菜蛾雌雄交配行为的分子机制，对于完善害虫对杀虫剂抗性进化理论具有积极和理论意义。