The fitness advantages of bistrifluron resistance related to chitin synthase A in Spodoptera litura (Fab.) (Noctuidae: Lepidoptera)

Abstract

BACKGROUND: Spodoptera litura is one of the major agricultural pests in China, and it has developed serious resistance to many traditional chemical insecticides. In the present study, the bistrifluron-resistant (Bis-SEL) strain accompanied by a higher oviposition, 113.8-fold RR compared to the bistrifluron-susceptible (Bis-UNSEL) strain, was obtained by bidirectional screening. A comparison of their gonad coefficiency and genes related to oviposition or resistance was used to elucidate the resurgence mechanism.RESULTS: The ovarian index, oviposition, and potential egg production in the Bis-SEL strain of female adults were significantly higher than those in the Bis-UNSEL strain, and the length of ovariole in the Bis-SEL strain was also significantly elongated. The protein contents of vitellogenin (Vg) and vitellogenin receptor (VgR) in the Bis-UNSEL strain were lower than those in the Bis-SEL strain, consistent with their gene expressions levels, and there was a significantly positive linear correlation between Vg and VgR protein contents, further confirming that resistant strains have high reproductive fitness. Moreover, the chitin synthase A in the Bis-SEL strain was clearly up-regulated, and a mutation (H866Y) near the QRRRW in the catalytic domain caused a rise in the hydrogen bond between UDP-GlcNAc and chitin synthase, and its chitin content was higher than that in the Bis-UNSEL strain. Nevertheless, the sensitivity of the Bis-SEL strain to bistrifluron was significantly recovered when it was knocked down though RNA interference. CONCLUSION:The fitness advantages of bistrifluron resistance may be related to the up-regulation and mution of chitin synthase A.

Characterization of Chitin Synthase A cDNA from Diaphorina citri (Hemiptera: Liviidae) and Its Response to Diflubenzuron

“…The increased level of CHS expression can also indicate the existence of a feedback regulation mechanism to compensate for low enzyme content [ 33 ]. However, upregulation or mutation of CHS expression can improve insect resistance [ 40 , 49 ]. As a result, we should pay more attention to the DcCHSA molecular mechanisms in drug resistance in the future.…”

Omani Frankincense nanoemulsion formulation efficacy and its latent effects on biological aspects of the spiny bollworm Earias insulana (Boisd.)

“…Growing insect resistance against insecticides has become one of the most critical problems for crop security due to the adverse effects of massively increased pesticide usage. It has already been demonstrated to be resistant to a variety of commonly used pesticides, including carbamates, pyrethroids, organophosphates, chlorantraniliprole, indoxacarb, abamectin, bistrifluron, and benzoate ( Gong et al, 2021 ; Li et al, 2021 ; Shi et al, 2021 ). Therefore, it is critical for integrated pest management to create new-target insecticides and efficient resistance management strategies.…”