The global regulator LaeA controls expression of genes involved in diverse primary and secondary metabolites biosynthesis and their secretion in fungi

LaeA is a global transcriptional regulator that differentially modulates expression of an impressive variety of secondary metabolite gene clusters in fungi, acting as a positive regulator fo some while repressing others. This regulator controls the production of fungal cellulolytic/ligninolytic enzymes and citric acid secretion in Ascomycetes. Also, it regulates the biosynthesis of siderophores and the antitumor agent ganoderic acid in Basidiomycetes. This regulator contains an S-adenosylmethionine-binding motif, suggesting a function as a methyltransferase, although its specific methylation substrate has not been identified. LaeA is a core component of the velvet complex, a five-membered proteins assembly that regulates fungal responses to light and environmental stresses. Within this complex, LaeA interacts with VeA, VosA and other velvet components forming dimers and trimers and the complexes bind to an eleven-nucleotide consensus sequence in the promoter of target genes. This article reviews current knowledge of LaeA and VeA mediated regulation, discusses outstanding challenges in the field, and highlights its potential in optimizing fungal metabolism, its biotechnological applications and its role in the control of fungal infections.