定虫隆对锈赤扁谷盗生长发育影响及其作用机理初探

定虫隆是一种昆虫生长调节抑制剂,研究其对锈赤扁谷盗的控制作用,将为锈赤扁谷盗的综合防治提供理论基础。本研究以锈赤扁谷盗幼虫为研究对象,用定虫隆拌粮进行饲喂,观察定虫隆对锈赤扁谷盗的亚致死效应,并利用实时荧光定量PCR(qPCR)技术,测定经定虫隆处理后锈赤扁谷盗幼虫几丁质合成酶1(CfCHS1)和几丁质合成酶2(CfCHS2)基因表达量的变化。结果表明:定虫隆对锈赤扁谷盗的毒力回归方程为y=7.514+1.81x(r=0.974),LD 10、LD 20、LD 30分别为0.008 mg/kg、0.014 mg/kg、0.021 mg/kg,亚致死剂量定虫隆可使锈赤扁谷盗幼虫发育历期明显延长(P<0.05),体重和几丁质含量明显降低(P<0.05),这说明了定虫隆对锈赤扁谷盗的生长发育有明显的抑制作用,可以有效控制锈赤扁谷盗的为害。qPCR结果显示,与对照组相比,LD 30处理后的锈赤扁谷盗幼虫的CfCHS 1基因表达量提高了74.7%,CfCHS 2基因的表达量提高了27.4%,均差异显著(P<0.05)。CfCHS 1和CfCHS2基因表达量的上调,可能是几丁质合成酶受到了抑制,锈赤扁谷盗为了维持机体的稳定,提高几丁质合成酶基因的表达量,从而形成一种代偿性增加的反馈机制,由此推测定虫隆可能作用于几丁质合成酶。

Effects and its mechanism of chlorfluazuron on the growth and development of Cryptolestes ferrugineus

Chlorfluazuron was an insect growth regulator.The study on effects of chlorfluazuron on Cryptolestes ferrugineus was studied to provide a theoretical basis for its comprehensive control.In this study,the larvae of C.ferrugineus were used as research objects,and the food was mixed by chlorfluazuron to observe the sublethal effect of chlorfluazuron on C.ferrugineus,also,the real-time quantitative PCR(qPCR)technology was used to study the changes of gene expression of chitin synthase 1(CfCHS1)and chitin synthase 2(CfCHS2)in C.ferrugineus after treatment with chlorfluazuron.The results showed that the virulence equation of chlorfluazuron was:y=7.514+1.81x(r=0.974),and LD 10,LD 20 and LD 30 were 0.008 mg/kg,0.014 mg/kg and 0.021 mg/kg.The development duration of larva was significantly prolonged(P<0.05),and the body weight and chitin content were significantly decreased(P<0.05).This suggested that chlorfluazuron could effectively inhibit the synthesis of chitin in C.ferrugineus,leading to prolonged developmental period and decreased body weight.The results of qPCR showed that compared with the control group,the expression level of CfCHS 1 gene increased by 74.7%and the expression level of CfCHS 2 gene increased by 27.4%after treatment on LD 30,and both differences were significant(P<0.05).The up-regulation of gene expression levels of CfCHS1 and CfCHS2 may be a compensatory increase in gene expression levels after chitin synthesis was blocked.The results showed that chlorfluazuron had obvious inhibitory effect on the growth and development of C.ferrugineus,and could be used to control C.ferrugineus.According to the results of qPCR,it was suggested that chlorfluazuron might act on chitin synthase.