Entomopathogenic fungi have been widely used as the main mycoinsecticide for controlling agricultural and forest pests.The effector molecules of these mycopathogens have evolved to adapt to their hosts.The role of fun...Entomopathogenic fungi have been widely used as the main mycoinsecticide for controlling agricultural and forest pests.The effector molecules of these mycopathogens have evolved to adapt to their hosts.The role of fungal effectors in evading the host immune system in insects remains mainly unclear.We characterized the widely distributed fungal effector necrosis-inducing-like secreted protein 1(NLS1)in the entomopathogenic fungus Metarhizium robertsii.Our findings revealed the presence of M.robertsii NLS1(MrNLS1)in host hemocytes during the early stage of hemocoel infection.MrNLS1 knock down(ΔMrNLS1)reduced fungal pathogenicity during infection and altered the expression of host immune genes.The molecular docking results and the yeast 2-hybrid assay confirmed that MrNLS1 interacts with the host defense protein Hdd11.The phylogenetic analysis indicated that Hdd11 is conserved across a broad range of Lepidoptera species.Knock down of hdd11 in Helicoverpa armigera,Bombyx mori,and Galleria mellonella markedly suppressed their immune responses against M.robertsii.However,no significant difference was observed in the mean lethal time between hdd11-knockdown Lepidoptera species infected withΔMrNLS1 and those infected with wild-type M.robertsii.Therefore,in Lepidoptera insects,Hdd11 is essential for fungal defense.In conclusion,M.robertsii infects Lepidoptera insects by targeting host Hdd11 through its protein MrNLS1,thereby suppressing the host immune response.Our findings clarify the molecular mechanisms underlying fungal infection pathogenesis.展开更多
The ascomycete insect pathogenic fungi such as Metarhizium species have been demonstrated with the abilities to form the rhizosphere or endophytic relationships with different plants for nutrient exchanges.In this stu...The ascomycete insect pathogenic fungi such as Metarhizium species have been demonstrated with the abilities to form the rhizosphere or endophytic relationships with different plants for nutrient exchanges.In this study,after the evident infeasibility of bacterial disease development in the boxed sterile soils,we established a hydroponic system for the gnotobiotic growth of Arabidopsis thaliana with the wild-type and transgenic strain of Metarhizium robertsii.The transgenic fungus could produce a high amount of pipecolic acid(PIP),a pivotal plant-immune-stimulating metabolite.Fungal inoculation experiments showed that M.robertsii could form a non-selective rhizosphere relationship with Arabidopsis.Similar to the PIP uptake by plants after exogenous application,PIP level increased in Col-0 and could be detected in the PIP-non-producing Arabidopsis mutant(ald1)after fungal inoculations,indicating that plants can absorb the PIP produced by fungi.The transgenic fungal strain had a better efficacy than the wild type to defend plants against the bacterial pathogen and aphid attacks.Contrary to ald1,fmo1 plants could not be boosted to resist bacterial infection after treatments.After fungal inoculations,the phytoalexins camalexin and aliphatic glucosinolate were selectively increased in Arabidopsis via both PIP-dependent and-independent ways.This study unveils the potential mechanism of the fungus-mediated beneficial promotion of plant immunity against biological stresses.The data also highlight the added values of M.robertsii to plants beyond the direct suppression of insect pest populations.展开更多
基金supported by National Science Foundation of China(Grant No.32102274)Hefei Municipal Natural Science Foundation(202312).
文摘Entomopathogenic fungi have been widely used as the main mycoinsecticide for controlling agricultural and forest pests.The effector molecules of these mycopathogens have evolved to adapt to their hosts.The role of fungal effectors in evading the host immune system in insects remains mainly unclear.We characterized the widely distributed fungal effector necrosis-inducing-like secreted protein 1(NLS1)in the entomopathogenic fungus Metarhizium robertsii.Our findings revealed the presence of M.robertsii NLS1(MrNLS1)in host hemocytes during the early stage of hemocoel infection.MrNLS1 knock down(ΔMrNLS1)reduced fungal pathogenicity during infection and altered the expression of host immune genes.The molecular docking results and the yeast 2-hybrid assay confirmed that MrNLS1 interacts with the host defense protein Hdd11.The phylogenetic analysis indicated that Hdd11 is conserved across a broad range of Lepidoptera species.Knock down of hdd11 in Helicoverpa armigera,Bombyx mori,and Galleria mellonella markedly suppressed their immune responses against M.robertsii.However,no significant difference was observed in the mean lethal time between hdd11-knockdown Lepidoptera species infected withΔMrNLS1 and those infected with wild-type M.robertsii.Therefore,in Lepidoptera insects,Hdd11 is essential for fungal defense.In conclusion,M.robertsii infects Lepidoptera insects by targeting host Hdd11 through its protein MrNLS1,thereby suppressing the host immune response.Our findings clarify the molecular mechanisms underlying fungal infection pathogenesis.
基金supported by the Chinese Academy of Sciences(XDPB16,QYZDJ-SSW-SMC028)the National Natural Science Foundation of China(32021001,31530001)。
文摘The ascomycete insect pathogenic fungi such as Metarhizium species have been demonstrated with the abilities to form the rhizosphere or endophytic relationships with different plants for nutrient exchanges.In this study,after the evident infeasibility of bacterial disease development in the boxed sterile soils,we established a hydroponic system for the gnotobiotic growth of Arabidopsis thaliana with the wild-type and transgenic strain of Metarhizium robertsii.The transgenic fungus could produce a high amount of pipecolic acid(PIP),a pivotal plant-immune-stimulating metabolite.Fungal inoculation experiments showed that M.robertsii could form a non-selective rhizosphere relationship with Arabidopsis.Similar to the PIP uptake by plants after exogenous application,PIP level increased in Col-0 and could be detected in the PIP-non-producing Arabidopsis mutant(ald1)after fungal inoculations,indicating that plants can absorb the PIP produced by fungi.The transgenic fungal strain had a better efficacy than the wild type to defend plants against the bacterial pathogen and aphid attacks.Contrary to ald1,fmo1 plants could not be boosted to resist bacterial infection after treatments.After fungal inoculations,the phytoalexins camalexin and aliphatic glucosinolate were selectively increased in Arabidopsis via both PIP-dependent and-independent ways.This study unveils the potential mechanism of the fungus-mediated beneficial promotion of plant immunity against biological stresses.The data also highlight the added values of M.robertsii to plants beyond the direct suppression of insect pest populations.
