The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global ...The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global gene expression profiling of Beauveria bassiana at 36, 60, 84 and 108 h after topical infection of Anopheles stephensi adult mosquitoes using RNA sequencing （RNA-Seq）. A total of 5,354 differentially expressed genes （DEGs） are identified over the course of fungal infection. When the fungus grows on the mosquito cuticle, up-regulated DEGs include adhesion-related genes involved in cuticle attachment, Pthl l-like GPCRs hypothesized to be involved in host recognition, and extracellular enzymes involved in the degradation and penetration of the mosquito cuticle. Once in the mosquito hemocoel, the fungus evades mosquito immune system probably through up-regulating expression of 13-1,3-glucan degrading enzymes and chitin synthesis enzymes for remodeling of cell walls. Moreover, six previous unknown SSCP （small secreted cysteine-rich proteins） are significantly up-regulated, which may serve as ＂effectors＂ to suppress host defense responses. B. bassiana also induces large amounts of antioxidant genes to mitigate host-generated exogenous oxidative stress. At late stage of infection, B. bassiana activates a broad spectrum of genes including nutrient degrading enzymes, some transporters and metabolism pathway components, to exploit mosquito tissues and hemolymph as a nutrient source for hyphal growth. These findings establish an important framework of knowledge for further comprehensive elucidation of fungal pathogenesis and molecular mechanism of Beauveria-mosquito interactions.展开更多
Insects and their natural microbial pathogens are intertwined in constant arms races,with pathogens continually seeking entry into susceptible hosts through distinct routes.Entomopathogenic fungi are primarily believe...Insects and their natural microbial pathogens are intertwined in constant arms races,with pathogens continually seeking entry into susceptible hosts through distinct routes.Entomopathogenic fungi are primarily believed to infect host insects through external cuticle penetration.Here,we report a new variety,Beauveria bassiana var.majus(Bbm),that can infect insects through the previously unrecognized foregut.Dual routes of infection significantly accelerate insect mortality.The pH-responsive transcription factor PacC in Bbm exhibits rapid upregulation and efficient proteolytic processing via PalC for alkaline adaptation in the foregut.Expression of PalC is regulated by the adjacent downstream gene Aia.Compared to non-enteropathogenic strains such as ARSEF252,Aia in Bbm lacks a 249-bp fragment,resulting in its enhanced alkaline-induced expression.This induction promotes PalC upregulation and facilitates PacC activation.Expressing the active form of BbmPacC in ARSEF252 enables intestinal infection.This study uncovers the pH-responsive Aia-PalC-PacC cascade enhancing fungal alkaline tolerance for intestinal infection,laying the foundation for developing a new generation of fungal insecticides to control destructive insect pests.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB11010500)National Key R&D Program of China(2017YFD0200400,SQ2017ZY060066)the Hundred Talents Program of the Chinese Academy of Sciences
文摘The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global gene expression profiling of Beauveria bassiana at 36, 60, 84 and 108 h after topical infection of Anopheles stephensi adult mosquitoes using RNA sequencing （RNA-Seq）. A total of 5,354 differentially expressed genes （DEGs） are identified over the course of fungal infection. When the fungus grows on the mosquito cuticle, up-regulated DEGs include adhesion-related genes involved in cuticle attachment, Pthl l-like GPCRs hypothesized to be involved in host recognition, and extracellular enzymes involved in the degradation and penetration of the mosquito cuticle. Once in the mosquito hemocoel, the fungus evades mosquito immune system probably through up-regulating expression of 13-1,3-glucan degrading enzymes and chitin synthesis enzymes for remodeling of cell walls. Moreover, six previous unknown SSCP （small secreted cysteine-rich proteins） are significantly up-regulated, which may serve as ＂effectors＂ to suppress host defense responses. B. bassiana also induces large amounts of antioxidant genes to mitigate host-generated exogenous oxidative stress. At late stage of infection, B. bassiana activates a broad spectrum of genes including nutrient degrading enzymes, some transporters and metabolism pathway components, to exploit mosquito tissues and hemolymph as a nutrient source for hyphal growth. These findings establish an important framework of knowledge for further comprehensive elucidation of fungal pathogenesis and molecular mechanism of Beauveria-mosquito interactions.
基金funded by the National Natural Science Foundation of China(grant nos.32021001,32230015,and 32272622)the National Key R&D Program of China(grant no.2023YFA1801000)+1 种基金the New Cornerstone Science Foundation,Chinese Academy of Sciences(317GJHZ2022028GC)Youth Innovation Promotion Association CAS(grant no.2021272).
文摘Insects and their natural microbial pathogens are intertwined in constant arms races,with pathogens continually seeking entry into susceptible hosts through distinct routes.Entomopathogenic fungi are primarily believed to infect host insects through external cuticle penetration.Here,we report a new variety,Beauveria bassiana var.majus(Bbm),that can infect insects through the previously unrecognized foregut.Dual routes of infection significantly accelerate insect mortality.The pH-responsive transcription factor PacC in Bbm exhibits rapid upregulation and efficient proteolytic processing via PalC for alkaline adaptation in the foregut.Expression of PalC is regulated by the adjacent downstream gene Aia.Compared to non-enteropathogenic strains such as ARSEF252,Aia in Bbm lacks a 249-bp fragment,resulting in its enhanced alkaline-induced expression.This induction promotes PalC upregulation and facilitates PacC activation.Expressing the active form of BbmPacC in ARSEF252 enables intestinal infection.This study uncovers the pH-responsive Aia-PalC-PacC cascade enhancing fungal alkaline tolerance for intestinal infection,laying the foundation for developing a new generation of fungal insecticides to control destructive insect pests.
