Functional Analysis Of The High Osmolarity-sensitive Protein MaSho1 In Metarhizium Acridum

Entomopathogenic fungi have the advantages of being environmentally friendly,low possibility to induce insect resistance and capable of achieving sustained control of pest populations.However,the lower efficacy compared with chemical pesticides severely limits their largescale application.In entomopathogenic fungi,conidia are the mainly infecting organs as well as the beginning and ending of cell differentiation process,playing an important role in the process of fungi growth,reproduction and infection.Sporulation capacity of fungi affects the control effect and production cost of pesticides directly.Therefore,the study of biocontrol traits and molecular mechanisms in entomopathogenic fungi have important theoretical significance and practical application value for fully exploiting its potential in biological control.Sho1 is an important transmembrane sensor upstream of the HOG-MAPK signaling pathway.HOG-MAPK signaling pathway is an important pathway in fungi,which involved in osmotic pressure response and played an important role in growth,tolerance and pathogenesis.In this research,the homologous protein MaSho1 that encoded 306 amino acids with four transmembrane domains(transmembrane domain,TM)and a SH3(Src homology 3 domain)domain was cloned from M.acridum.The functions of MaSho1 and were characterized using disruption and complementation strategies.Compared with the wild type,disruption of MaSho1 reduced the fungi tolerances to UV-B irradiation,but not affect heat shock.Moreover,the cell wall integrity in M.acridum was destroyed after the deletion of MaSho1.The oxidative and osmotic stress resistance were significantly reduced after both disruption of the MaSho1 and SH3 domain in M.acridum.Bioassays by topical inoculation showed that the pathogenicity was significantly reduced in ?MaSho1 mutant.And compared with the wild type,the spacing was significantly shorten,conidial yield increased significantly,but no affect in conidial germination in ?MaSho1.Interestingly,the conidiation pattern shift from normal conidiation to microcirculation conidiation in 1/4 SDAY medium when MaSho1 was deleted.Furthermore,the result of digital gene expression profile in sporulation period indicated that there were 103 differentially expressed genes(DGEs)after MaSho1 deletion.Twenty-three DEGs regulated by MaSho1 were associated with mycelial development,cell division,and sporulation.In addition,the differentially expressed genes were also involved in the regulation of sporulation-related pathways.These results indicated that ?MaSho1 inhibited the mycelial growth by regulating the sporulation-related pathways and the expression of genes involved in cell division and differentiation,mediated the conidiation patterns shift,thereby promoted the conidial production.These above results indicated that high osmolarity-sensitive protein MaSho1 was involved in the regulation of pathogenicity,and regulated conidiation by mediating mycelial growth and conidiation patterns shift in M.acridum.Therefore,in-depth research on the molecular mechanism of MaSho1 in conidiation patterns shift is beneficial to increasing conidia yield and insecticidal efficiency,and has important theoretical significance and practical application value for large-scale production in the future.