Gene Knock-out Of Bbhog1 Decreases Virulence And Adversity Resistance In Beauveria Bassiana

Entomopathgenic fungi are one of vital microorganisms to control pests and have potentials in biological control. However, so far, the molecular mechanism on infecting host and pathogenicity of entomopathogenic fungi has been poorly understood, which deterred the exploitation of fungi insecticides. The mitogen-activated protein (MAP) kinases are the serine/threonine protein kinases in eukaryotes. MAPK cascades amplify and transfer extracellular signals through phosphorylation step by step. Microbiology can make a series of corresponding responds to the induction of surrouding signals through MAPK cascades. Recent studies have indicated that MAPK signal transduction pathways are closely relative to development, cell differentiation or pathogenicity of phytopathgenic as well as mammal pathogenic fungi. These pathways are important objects of the research about molecular mechanism in the process of invading host. Nevertheless what effects MAPK signal pathways in entomopathogenic fungi have on resistant abilty and virulence has still remained to be seen.Bbhogl gene, homologous to yeast H0G1, was cloned successfully from an entomopathogenic fungus Beauveria bassiana by our group. To shed light on the function of Bbhogl, we utilize homologous recombination to knock out Bbhogl in Beauveria bassiana and analyse the effect of mutants on resistant ablity and virulence, which will lay the foundations to investigate further MAPK signal pathways during entomopathogenic fungi development, cell differentiation, infecting or pathogenisis.The results are as fallowings:1. Four mutants of Beauveria bassiana, knocked out Bbhogl by homologous recombination, were generated and named as ABbhogl255 ,ABbhogl456, ABbhogl461 and ABbhogl484, respcectively. Southern blot analysis showed that foreign fragment was integrated into Beauveria bassiana genome with a single copy. The native Bbhogl (2.3kb) in Beauveria...