中国二化螟田间种群对氯虫苯甲酰胺的抗性监测及鱼尼丁受体基因突变检测OA

[Aim]To characterize the resistance of the field populations of Chilo suppressalis to chlorantraniliprole,determine the frequencies of resistance-associated mutations in the target of diamide insecticides,the ryanodine receptor(RyR),and develop a rapid loop-mediated isothermal amplification(LAMP)assay for detection of the Y4667D target-site mutation.[Methods]In 2025,the field populations of C.suppressalis were collected from 32 locations across nine provinces(municipalities)in China.The median lethal concentration(LC50)value of chlorantraniliprole against the 2nd instar larvae of C.suppressalis at 5 d after exposure was determined using the rice-seedling dipping method.The cDNA fragment containing the target mution sites in CsRyR of the 4th instar larvae of C.suppressalis populations was amplified by PCR,and the mutation types and frequencies of CsRyR were determined based on sequencing results.Using the genomic DNA of C.suppressalis as the template,specific primers targeting the Y4667D mutation of CsRyR were designed for LAMP.[Results]Bioassay results showed that the LC50 values of chlorantraniliprole against the 2nd instar larvae of 27 field populations of C.suppressalis at 5 d after exposure were 1.915-1 733.883 mg/L,and the resistance ratios of the 27 field populations of C.suppressalis to chlorantraniliprole ranged from 1.4 to 1 244.7.Among them,18 populations of C.suppressalis exhibited high levels of resistance to chlorantraniliprole,the populations from Huzhou,Zhejiang and Dafeng,Jiangsu showed moderate resistance levels,the populations from Suqian and Yizheng,Jiangsu displayed low resistance level,whereas several populations from Sichuan and Hubei remained susceptible.A total of five missense mutations,including Y4667D/C,I4758M,Y4891F and G4915E,were identified in CsRyR.Among them,I4758M was the most widespread and frequent mutation,Y4667D/C mainly occurred in heterozygous form,whereas G4915E was detected only at low frequencies in a few populations.A LAMP assay targeting the Y4667D point mutation in CsRyR was established.[Conclusion]Most field populations of C.suppressalis in China have developed high levels of resistance or are undergoing resistance development to chlorantraniliprole,accompanied by relatively high frequencies of resistance-associated mutations.These findings highlight the need for cautious use of chlorantraniliprole in resistance management programs of C.suppressalis and emphasize the importance of continuous resistance monitoring to delay further evolution of resistance.