摘要
Mounting evidence suggests that insect hormones associated with growth and development also participate in pathogen defense.We have discovered a previously undescribed midgut transcriptional control pathway that modulates the availability of 20-hydroxyecdysone(20E)in a worldwide insect pest(Plutella xylostella),allowing it to defeat the major virulence factor of an insect pathogen Bacillus thuringiensis(Bt).A reduction of the transcriptional inhibitor(PxDfd)increases the expression of a midgut microRNA(miR-8545),which in turn represses the expression of a newly identified ecdysteroid-degrading glucose dehydrogenase(PxGLD).Downregulation of PxGLD reduces 20E degradation to increase 20E titer and concurrently triggers a transcriptional negative feedback loop to mitigate 20E overproduction.The moderately elevated 20E titer in the midgut activates a MAPK signaling pathway to increase Bt tolerance/resistance.These findings deepen our understanding of the functions attributed to these classical insect hormones and help inform potential future strategies that can be employed to control insect pests.
基金
supported by the National Natural Science Foundation of China(32221004,32172458,and 32372600)
the China Postdoctoral Science Foundation(2023M733828)
the earmarked fund for CARS(CARS-23),the Central Public-interest Scientific Institution Basal Research Fund(Y2024XK01)
the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables,and the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSCB-202303).
