Requirement of LaeA for secondary metabolism and sclerotial production in Aspergillus flavus

Abstract

The nuclear regulator LaeA has been shown to govern production of multiple secondary metabolites in A. nidulans and A. fumigatus. Herein we examine the role of this protein in Aspergillus flavus. Similarly as in other Aspergilli, LaeA had a major effect on A. flavus secondary metabolism where ΔlaeA and over-expression laeA (OE::laeA) strains yielded opposite phenotypes resulting in decreased (increased) secondary metabolite production. The two mutant strains also exhibited striking morphological phenotypes in the loss (increase) of sclerotial production in comparison to wildtype. Growth on seed was marked by decreased (increased) conidial and aflatoxin production of the respective mutants; this was accompanied by decreased lipase activity in ΔlaeA, an enzymatic process correlated with seed maceration. Transcriptional examination of the mutants showed LaeA negatively regulates expression of its recently identified nuclear partner VeA, another global regulator of A. flavus secondary metabolites and sclerotia.

Fungal antioxidant pathways promote survival against neutrophils during infection

“…For our studies on gliotoxin, June Kwon-Chung (NIAID, Bethesda, Maryland, USA) provided A. fumigatus strains B-5233 (WT), ΔgliP, and gliPR (77). Additionally, Nancy Keller (University of Wisconsin, Madison, Wisconsin, USA) provided the A. fumigatus strains Af293 (WT), ΔgliZ, gliZR, ΔlaeA, laeA-R, as well as the Aspergillus flavus strains A. flavus NRRL3357 (WT), ΔlaeA, and laeA-R (78,79). For ROS scavenging studies, we used A. fumigatus strains G10 (WT), ΔcatA, and Δcat1/2, and Ku80 (WT), Δsod1/2/3, and Dal (WT), Δyap1 (36)(37)(38).…”

Aspergillus oryzae laeARegulates Kojic Acid Synthesis Genes

“…4) According to another study, KA production was lost in the laeA disruption (ÁLaeA) strain in A. flavus, 5) but it was uncertain how LaeA controlled KA production. To elucidate laeA regulation of KA production in A. oryzae, we produced a disruption mutant.…”

Effect of Environmental Change on Secondary Metabolite Production in Lichen-Forming Fungi

“…Another gene, laeA, has also been shown to regulate expression of biosynthetic gene clusters in species of Aspergillus (Bok & Keller, 2004;Keller et al, 2005;Fox & Howlett, 2008). In addition, it has been shown that laeA negatively affects the regulation of veA (Kale et al, 2008). The loss of laeA results in gene silencing (Bok et al, 2006b;Perrin et al, 2007).…”