The tobacco whitefly, Bemisia tabaci, is a notorious pest affecting various crops globally, and it exhibits high levels of resistance to various insecticides. Afidopyropen is a recently commercialized pyropene insecticide for B. tabaci control with high selectivity and a novel mode of action. We previously identified a high level of afidopyropen resistance in a field-collected population after selection in the lab, and named it the HD-Afi strain. In the present study, minimal cross-resistance in the HD-Afi strain was found between afidopyropen and other common chemical agents. However, the P450 enzyme activity in HD-Afi was 2.18 times the level in susceptible strain HD-S. Expression analysis revealed that two of 12 candidate P450 genes, namely CYP6DW3 and CYP4C64, were significantly up-regulated in HD-Afi. Silencing CYP6DW3 and CYP4C64 by RNA interference (RNAi) substantially increased the susceptibility of whitefly adults, confirming their involvement in afidopyropen resistance. Homology modeling and molecular docking analyses demonstrated stable binding of afidopyropen to CYP6DW3 and CYP4C64, with binding free energies of –6.87 and –6.11 kcal mol–1, respectively. The findings of this study suggest that the induction of CYP6DW3 and CYP4C64 facilitates afidopyropen detoxification, contributing to the development of resistance in B. tabaci.
The postharvest senescence phase of table grapes comprises a series of biological processes. MicroRNAs (miRNAs) regulate downstream genes at the post-transcriptional level; however, whether miRNAs are involved in postharvest grape senescence remains unclear. We used small RNA sequencing to identify postharvest-related miRNAs in ‘Red Globe’ (Vitis vinifera) grapes harvested after 0, 30, and 60 d at 4 °C (RG0, RG30, RG60). In total, 42 known and 219 novel miRNA candidates were obtained. During fruit senescence, the expression of PC-3p-3343_1921, miR2950, miR395k, miR2111, miR159c, miR169q, PC-5p-1112_4500, and miR167b changed significantly (p<0.05). Degradation sequencing identified 218 targets associated with cell wall organization, TCA cycling, pathogen defense, carbon metabolism, hormone signaling, the anthocyanin metabolism pathway, and energy regulation, of which ARF6, GRF3, TCP2, CP1, MYBA2, and WRKY72 were closely related to fruit senescence. We also verified VIT_00s2146g00010, VIT_02s0012g01750, and VIT_03s0038g00160 with unknown functions cleaved by senescence-related PC-5p-1112_4500 via the dual luciferase assay and transient transformation of grape berries and showed that they regulate berry senescence. These results deepen the understanding of the contribution of miRNAs in regulating grape berry senescence and prolonging the shelf life of horticultural products. Based on these results, we propose a new theoretical strategy to delay the postharvest senescence of horticultural products by regulating the expression of key miRNAs (e.g., PC-5p-1112_4500), thereby extending their shelf life.