title: rtfA, a putative RNA-Pol II transcription elongation factor gene, is necessary for normal morphological and chemical development in Aspergillus flavus.
abstract: The filamentous fungus Aspergillus flavus is an agriculturally important opportunistic plant pathogen that produces potent carcinogenic compounds called aflatoxins. We identified the A. flavus rtfA gene, the ortholog of rtf1 in Saccharomyces cerevisiae and rtfA in Aspergillus nidulans. Interestingly, rtfA has multiple cellular roles in this mycotoxin-producing fungus. In this study, we show that rtfA regulates conidiation. The rtfA deletion mutant presented smaller conidiophores with significantly reduced conidial production compared to the wild-type strain. The absence of rtfA also resulted in a significant decrease or lack of sclerotial production under conditions that allowed abundant production of these resistance structures in the wild type. Importantly, the deletion of rtfA notably reduced the production of aflatoxin B1, indicating that rtfA is a regulator of mycotoxin biosynthesis in A. flavus. In addition, the deletion rtfA also altered the production of several unknown secondary metabolites indicating a broader regulatory scope. Furthermore, our study revealed that rtfA controls the expression of the global regulators veA and laeA, which further influence morphogenesis and secondary metabolism in A. flavus.
authors.affiliation: Department of Biological Sciences, Northern Illinois University, 155 Castle Dr., Dekalb, IL, 60115, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Lohmar
authors.affiliation: Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, LA, 70124, USA.
authors.forename: Pamela Y
authors.initials: PY
authors.lastname: Harris-Coward
authors.affiliation: Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, LA, 70124, USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Cary
authors.affiliation: Department of Biological Sciences, Northern Illinois University, 155 Castle Dr., Dekalb, IL, 60115, USA.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Dhingra
authors.affiliation: Department of Biological Sciences, Northern Illinois University, 155 Castle Dr., Dekalb, IL, 60115, USA. amcalvo@niu.edu.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Calvo
mesh_terms: D016604:Aflatoxin B1 / Q000378:metabolism; D001231:Aspergillus flavus / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D010445:Peptide Elongation Factors / Q000235:genetics* / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics* / Q000378:metabolism; D064210:Secondary Metabolism; D013172:Spores, Fungal / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D010445:Peptide Elongation Factors; D016604:Aflatoxin B1; D012319:RNA Polymerase II
keywords: Aflatoxin; Aspergillus flavus; Conidiation; Sclerotium; Secondary metabolism; rtfA