title: RmtA, a Putative Arginine Methyltransferase, Regulates Secondary Metabolism and Development in Aspergillus flavus.
abstract: Aspergillus flavus colonizes numerous oil seed crops such as corn, peanuts, treenuts and cotton worldwide, contaminating them with aflatoxin and other harmful potent toxins. In the phylogenetically related model fungus Aspergillus nidulans, the methyltransferase, RmtA, has been described to be involved in epigenetics regulation through histone modification. Epigenetics regulation affects a variety of cellular processes, including morphogenesis and secondary metabolism. Our study shows that deletion of rmtA in A. flavus results in hyperconidiating colonies, indicating that rmtA is a repressor of asexual development in this fungus. The increase in conidiation in the absence of rmtA coincides with greater expression of brlA, abaA, and wetA compared to that in the wild type. Additionally, the rmtA deletion mutant presents a drastic reduction or loss of sclerotial production, while forced expression of this gene increased the ability of this fungus to generate these resistant structures, revealing rmtA as a positive regulator of sclerotial formation. Importantly, rmtA is also required for the production of aflatoxin B1 in A. flavus, affecting the expression of aflJ. Furthermore, biosynthesis of additional metabolites is also controlled by rmtA, indicating a broad regulatory output in the control of secondary metabolism. This study also revealed that rmtA positively regulates the expression of the global regulatory gene veA, which could contribute to mediate the effects of rmtA on development and secondary metabolism in this relevant opportunistic plant pathogen.
authors.affiliation: Department of Biological Sciences, Northern Illinois University, Dekalb, IL, 60115, United States of America.
authors.forename: Timothy
authors.initials: T
authors.lastname: Satterlee
authors.affiliation: USDA, ARS, Southern Regional Research Center, New Orleans, LA, 70124, United States of America.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Cary
authors.affiliation: Department of Biological Sciences, Northern Illinois University, Dekalb, IL, 60115, United States of America.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Calvo
mesh_terms: D000595:Amino Acid Sequence; D001231:Aspergillus flavus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005800:Genes, Fungal; D010802:Phylogeny; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics / Q000502:physiology*; D064210:Secondary Metabolism / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D005656:Fungal Proteins; D011484:Protein-Arginine N-Methyltransferases