RESEARCH PROGRESSES OF AFLATOXIN BIOSYNTHETIC REGULATION BY LAEA

The highly mutagenic and carcinogenic mycotoxin aflatoxin is mainly produced by Aspergillus flavus and Aspergillus parasiticus.The pathogenic fungus Aspergillus flavus contaminates wheat,corn,cotton,and peanuts pre-and post-harvest and can produce amount of aflatoxins which causes huge economic loss for the world agricultural economy and threathens food safety and human health.The physicochemical properties,biological toxicity,biosynthetic pathway,production conditions and regulatory mechanism of aflatoxin have been extensively studied since its discovery in 1960s.More than thirty genes involved in aflatoxin biosynthetic pathway and clustered in an area about 80 Kb on a genome,named AF gene cluster,and the expression level of each gene can affect the production of aflatoxin.The previous research indicated that the biosynthesis of aflatoxin was regulated by several factors,including carbon source,nitrogen source,pH,temperature,humidity,pathway-specific regulator aflR,and global regulator LaeA,wherein LaeA showed unique properties,regulating secondary metabolism and development of filamentous fungi and affecting morphological differentiation of mycelia,aflatoxin synthesis and the expression of silent gene clusters.In order to provide information of LaeA for futher research,the paper summarized the discovery,function and regulation mechanism of LaeA in fungi,and emphasized on the latest progress of LaeA in regulating biosynthesis of Aspergillus flavus.This review presented the primary regulatory process of aflatoxin biosynthesis and will provide more insights into the research of aflatoxin regulated by LaeA.