The filamentous fungi in the genus Aspergillus are opportunistic plant and animal pathogens that can adapt to their environment by producing various secondary metabolites, including lovastatin, penicillin, and aflatoxin. The synthesis of these small molecules is dependent on gene clusters that are globally regulated by the LaeA protein. Null mutants of LaeA in all pathogenic fungi examined to d...

LaeA is a fungal specific virulence factor of both plant and human pathogenic fungi. Transcriptional profiles of laeA mutants have been successfully exploited to identify regulatory mechanisms of secondary metabolism in fungi; here we use laeA mutants as tools to elucidate virulence attributes in Aspergillus flavus. Microarray expression profiles of ΔlaeA and over-expression laeA (OE::laeA) wer...

Cellulolytic enzyme hydrolysis of lignocellulose biomass to release fermentable sugars is one of the key steps in biofuel refining. Gene expression of fungal cellulolytic enzymes is tightly controlled at the transcriptional level. Key transcription factors such as activator ClrB/CLR2 and XlnR/XYR1, as well as repressor CreA/CRE1 play crucial roles in this process. The putative protein methyltra...

Fungal secondary metabolism has become an important research topic with great biomedical and biotechnological value. In the postgenomic era, understanding the diversity and the molecular control of secondary metabolites (SMs) are two challenging tasks addressed by the research community. Discovery of the LaeA methyltransferase 10 years ago opened up a new horizon on the control of SM research w...

The alb1 (pksP) gene has been reported as a virulence factor controlling the pigmentation and morphology of conidia in Aspergillus fumigatus. A recent report suggested that laeA regulates alb1 expression and conidial morphology but not pigmentation in the A. fumigatus strain AF293. laeA has also been reported to regulate the synthesis of secondary metabolites, such as gliotoxin. We compared the...

Aspergillus flavus is a saprophytic soil fungus that poses a serious threat worldwide as it contaminates many food and feed crops with the carcinogenic mycotoxin called aflatoxin. This pathogen persists as sclerotia in the soil which enables fungal survival in harsh environmental conditions. Sclerotia formation by A. flavus depends on successful cell communication and hyphal fusion events. Loss...

Aflatoxins (AFs) are carcinogenic secondary metabolites of Aspergillus parasiticus. In previous studies, non-toxigenic A. parasiticus sec- (for secondary metabolism negative) variants were generated through serial transfer of mycelia from their toxigenic sec+ (for secondary metabolism positive) parents for genetic and physiological analysis for understanding regulation of AF biosynthesis. Previ...

Secondary metabolites, including toxins and melanins, have been implicated as virulence attributes in invasive aspergillosis. Although not definitively proved, this supposition is supported by the decreased virulence of an Aspergillus fumigatus strain, DeltalaeA, that is crippled in the production of numerous secondary metabolites. However, loss of a single LaeA-regulated toxin, gliotoxin, did ...

Ochratoxin A (OTA) is a mycotoxin with nephrotoxic, teratogenic and immunotoxic properties which represents a serious risk for human and animal health. Aspergillus carbonarius is considered the main OTA-producing species in grapes and products such as raisins, wine or juices, although it has also been isolated from coffee, cocoa and cereals. Till now not much information is available about regu...

The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric a...