Determination of nAChR β 1 Subunit Mutation and Resistance to Imidacloprid in Myzus persicae (Sulzer)

Myzus persica (Sulzer) is an important agricultural pest that indirectly spreads plant viruses by feeding on plant leaves, causing significant impacts on agricultural production. Neonicotinoid insecticides exert their insecticidal effects by specifically targeting the nicotinic acetylcholine receptors (nAChRs) in the insect nervous system, thereby interfering with neural signal transduction. However, their frequent use has led to severe resistance. The mutations of the nicotinic acetylcholine receptor β 1 subunit (nACh β 1) in insecticide resistance formation as an important target deserve attention. So, in this study, resistance level determination, gene mutation point detection (R81T and V101I), and nAChR β1 gene expression analysis in different populations were conducted. The results showed that seven field populations collected in four provinces of China exhibited resistance to imidacloprid (resistance factor [RF] range, 3.27–108.00). The V101I mutation frequency is not found in the HNZMD population, whereas varying degrees occur in the other six populations (ranging from 10% to 100%), and this mutation frequency is significantly positively correlated with resistance level to imidacloprid. However, the R81T mutation only appeared in the HNHB and HNZMD populations, with mutation frequencies of 50% and 20%, respectively, and was not detected in the other five populations. The mRNA relative expression levels of nAChR β1 subunit showed no significant differences among the sensitive strain (MP‐S), HNLY, JSLYG, CQDZ, and HNZMD. However, the nAChR β1 subunit was reduced by 60.7%, 58.7%, and 49.6% in HNHB, ZJHZ, and HNXX compared with that of MP‐S, respectively. This suggests that both point mutation (V101I) and the downregulation of nAChR β1 subunit expression may be involved in the resistance to imidacloprid. These results should be useful for the management of imidacloprid‐resistant M. persicae .