The Effect Of Salicylic Acid Metabolism On Stress Tolerance And Pathogenicity In Metarhizium Acridum

Entomopathogenic fungi are the largest category of insect pathogens. Entomopathogenic fungi have characteristics of contacting, kill, non-pollution and prevention of resurgence and so on. Therefore, entomopathogenic fungi have huge potential for killing insect. However, entomopathogenic fungi have some disadvantages, for example, unstable and slow effeciency of insecticidal. Clearly understand the pathogenic machanism of entomopathogenic fungi will hep lay the theoretical basis for for construction strains with high efficiency.At present, many researchers have studied the function of salicylic acid especially in plant. In plant, salicylic acid is an important signal molecule on immune response. But, the function of salicylic acid metabolism in entomopathogenic fungi is not clear. In this study, MaSalH1, MaSalH2 and MaSalS was functionally characterized in the entomopathogenic fungus Metarhizium acridum using gene deletion technique.The main results were as follows:(1)MaSalH1, MaSalH2 and MaSalS did not affect the fungal cell wall integrity and tolerance to oxidative stress.(2)The growth of Metarhizium acridum were affected with a certain of exogenous salicylic acid.(3) In M. acridum, Ma SalH1, MaSalH2 and MaSalS affected virulence by influencing cellular immunity of Locusta migratoria manilensis, MaSalH1 and MaSalH2 attenuated virulence, MaSalS enhanced virulence.(4)The relatively expression of MaSalH1 and Ma SalS was the highest in period of spore and the lowest in period of germinate, the elatively expression of MaSalH2 was the highest in period of hyphal body and the lowest in period of germinate, in the wild type of M. acridum.(5)M. acridum could produce salicylic acid.Taken together, these results demonstrated salicylic acid metabolism did not affect the ability of stress tolerance and has a significant effect of virulence in M. acridum.