A nonribosomal peptide synthetase mediates siderophore production and virulence in the citrus fungal pathogen Alternaria alternata

摘要: Summary Alternaria species produce and excrete dimethyl coprogen siderophores to acquire iron. The Alternaria alternata gene AaNPS6, encoding a polypeptide analogous fungal nonribosomal peptide synthetases, was found be required for the production of virulence on citrus. Siderophores purified from culture filtrates wild-type strain did not induce any phytotoxicity leaves Fungal strains lacking AaNPS6 produced little or no detectable extracellular displayed an increased sensitivity H2O2, superoxide-generating compounds (KO2 menadione) iron depletion. Δnps6 mutants were also defective melanin conidia. introduction under control its endogenous promoter null mutant at least partially restored siderophore citrus, demonstrating functional link between uptake pathogenesis. Elevated seen could relieved by exogenous application ferric expression highly up-regulated low-iron conditions apparently controlled redox-responsive yeast transcriptional regulator YAP1. Hence, maintenance homeostasis via siderophore-mediated plays important role in resistance toxic reactive oxygen (ROS). Our results demonstrate further critical ROS detoxification pathogenicity A. alternata