Preliminary Function Study Of MAPK Pathways Related Genes In Aspergillus Flavus

Aspergillus flavus is a common saprophytic fungus that can easily contaminate peanuts,corn and other crops.Aflatoxins(Afs)which are produced by A.flavus have a strong teratogenic and carcinogenic effect on human and animals.A.flavus and AFs have caused huge economic losses and health hazards worldwide.The process of AFs synthesis has been well studied,but the regulatory mechanism of A.flavus growth and AFs synthesis affected by environmental stimuli were not very clear.The former studies of MAPK signaling pathway in yeast,A.nidulans and other fungi provided us an insight into the role of MAPK genes might have in the growth and pathogenesis of A.flavus.In this study,knockout technology,was used to construct ? fus3 and? ste11 knockout mutants.Phenotypic analysis showed that inactivation of fus3 and ste11 caused a reduction of conidium production and defect in the sclerotia formation.However,these two muntants showed no effects on growth rate compared with wild-type strain.AF production of these two muntants were detected by thin layer chromatography,which showed that deletion of fus3 and ste11 lead to a decrease in AF synthesis.Infection experiments showed that the ability of?fus3 and ?ste11 mutant infesting peanut decreased significantly.Adding to these,complemented vector of ?fus3 and ?ste11 mutants were constructed and amino acid point mutantion were performed to study the functions of these protein kinases in growth and AF biosynthesis of A.flavusIn sum these results preliminarily proved that MAPK pathway-related genes played an important role in A.flavus growth,pathogenicity and AF synthesis.These will help us to further understanding the regulatory mechanism of A.flavus growth and AFs biosynthesis by environmental stimuli and provide a theoretical basis for the precaution of harms from A.flavus and AFs.