Function Of AflM And HexA In Aspergillus Flavus

In the past few years,the food security crisis has been a hot point that is concerned commonly by the world.It is not only related to the health of the human beings,but also closely connected with the development of human society.Crops are very susceptible to be contaminated by heavy metal,farm chemical and many different kinds of fungi.And aflatoxin is one of the main pollution sources.In order to explore the biosynthesis mechanism of aflatoxin in Aspergillus flavus,two genes were studied,aflM and hexA,which are related to aflatoxin synthesis.aflM which encodes a 28-kDa NADPH-dependent reductase is one of the important genes in the synthesis pathway of aflatoxin.In the study,the aflM was succeeded to be knocked out and complemented(△ aflM and △ aflM.com).The results showed that the synthesis of AFB1 was completely inhibited in △ aflM.Compared to the wild-type strains(WT)and complementary strains(△aflM.com),the growth and sclerotium production of△aflM are also weakened.So,it suggested that aflM would be an essential important gene in the AFB1 biosynthesis pathway and also has a significant regulation function in Aspergillus flavus’s growth and sclerotium production.Woronin bodies are fungal-specific organelles whose formation are derived from peroxisomes,and they are important parts of damage repair mechanisms in fungi.According to the report,woronin bodies may have some similar functions as peroxisome.It may involves in the regulation of biosynthesis of mycotoxins.The protein that is encoded by hexA gene is a main and essential component of woronin body.Two mutants were constructed successfully(△hexA-11 and △hexA-12 it was found that there was a significant decrease in condia and AFB1 production.In addition,their infection ability on peanut appeared obviously weakened.Therefore,it suggested that the hexA gene not only has a certain function in invasion to peanut and the condia production of Aspergillus flavus,but is a regulation factor in AFB1 biosynthesis.In this study,two genes in Aspergillus flavus and AFB1 biosynthesis were investigated.It laid a foundation for further study on the mechanism of the synthesis and regulation of AFB1 in Aspergillus flavus,and would provides a new strategy and theoretical support for the prevention of aflatoxin contamination.