The Study On WSC Member Proteins AflWsc1 And AflWsc2 Of CWI In Aspergillus Flavus

Wsc proteins are major components of Cell Wall Integrity,which plays roles in responding environmental stress,Being a saprophytic soil fungus,Aspergillus flavus is regarded as a model for the study of fungal growth and secondary metabolism.Recently,change in environmental signals is shown to be associated with biosynthesis of aflatoxin(AF),which is the most toxicity secondary metabolism in A.flavus.Thus,we speculate that CWI pathway might be involved in AF biosynthesis.In this study,we identified two CWI sensors AflWscl and AflWsc2 in A.flavus using bioinformatics methods,and constructed their gene deletion mutants.Our results showed that disruption of AflWscl caused a inhibition in fungal growth and decline in sclerotial formation.A delay in spore germination was also found in?AflWsc1.In addition,we found that disruption of AflWsc2 caused an apparent inhibition in fungal growth,but showing not difference in sclerotial formation compared to WT.Adding to these,microscopy observation showed that hyphal from?AflWsc2 displayed swollen phenotype.A reduction conidiation was also found both in?AflWscl and ?AflWsc2.Besides,we found that both AflWscl and AflWsc2 were involved in AF biosynthesis in A.flavus.In order to know if AflWscl and AflWsc2 were functional redundancy in A.flavus,we constructed a double-deletion mutant of?AflWsc1?AflWsc2,demonstrating that the growth of ?AflWsc1?AflWsc2 mutant was apparently decreased compared to wild-type and ?AflWsc2 strains.These result indicated that AflWscl and AflWsc2 are redundant in A.flavus.When adding environmental stress,?AflWscl showed sensitivity to the cell wall disrupters agents Congo red,calcofluor white,and antifungal agents caspofungin,and ?AflWsc2 demonstrate contrary function.However,none strain showed difference in fungal growth under oxidation stress.We also found that AflWscl and AflWsc2 played roles in response to osmotic environment stress.These results indicate that AflWscl and AflWsc2 involve in asexual development and AF biosynthesis,and play roles in response to cell wall and osmotic environment stress in A.flauvs.This study pave the way for revealing stress response pathway and developing antifungal means.