Resistance allele frequencies of Chilo suppressalis populations to Cry1Ab in Chongqing

• Published in: Journal of Asia-Pacific entomology Vol. 28; no. 2; pp. 102423 - 6
• Main Authors: Lu, Wencai, Ma, Lianjie, Chen, Xingru, Wang, Dong, Wang, Yan, Zhang, Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2025; 한국응용곤충학회
• Subjects: Bacillus thuringiensis; Chilo suppressalis; Cry1Ab; Resistance allele frequency; Sensitivity; 농학; Sensitivity; Cry1Ab; Chilo suppressalis; Bacillus thuringiensis; Resistance allele frequency
• ISSN: 1226-8615; 1876-7790
• DOI: 10.1016/j.aspen.2025.102423

[Display omitted] •The resistance allele frequencies to Cry1Ab were determined in Chilo suppressalis.•The resistant strains of C. suppressalis against Cry1Ab are established.•The egg-F2 screening method is suitable for detecting resistance alleles. Transgenic rice expressing Bacillus thuringiensis (Bt) insecticidal toxins for insect resistance represent a novel method of controlling Chilo suppressalis; however, potential resistance of pests to Bt toxins is a key factor restricting sustainable application of transgenic Bt crops. Here, we assessed the initial risk of resistance to transgenic Bt rice in local C. suppressalis populations in the municipality of Chongqing in China by testing their sensitivities to Bt proteins and determining resistance allele frequencies. Toxicity testing showed that sensitivity of C. suppressalis populations to Bt toxins (Cry1Ab and Cry1Ac) varied across geographical areas (LC50 ranges, 1.39–7.14 and 3.02–8.81 mg/L, respectively), with sensitivity of the Fengjie population to Cry1Ab 5.13-fold that of the Nanchuan population. F2 screening showed that resistance allele frequencies to Cry1Ab in C. suppressalis larvae, pupae, and adults in Chongqing were 0.0048, 0.0050, and 0.0053 during 1999–2021, respectively. After 20 generations of resistance selection using Cry1Ab, the resistance level of the C. suppressalis population was 15.67-fold that of the initial population. These results demonstrate the presence of Bt protein-resistant C. suppressalis individuals, and a risk of producing resistant C. suppressalis populations, in the field in Chongqing, China.