1887

Abstract

The ability of the necrotrophic fungus to detoxify reactive oxygen species (ROS) is crucial for pathogenesis to citrus. We report regulation of siderophore-mediated iron acquisition and ROS resistance by the NADPH oxidase (NOX), the redox activating yes-associated protein 1 (YAP1) regulator, and the high-osmolarity glycerol 1 (HOG1) mitogen-activated protein kinase (MAPK). The nonribosomal peptide synthetase (NPS6) is essential for the biosynthesis of siderophores, contributing to iron uptake under low-iron conditions. Fungal strains impaired for NOX, YAP1, HOG1 or NPS6 all display increased sensitivity to ROS. Exogenous addition of iron at least partially rescues ROS sensitivity seen for NPS6, YAP1, HOG1, and NOX mutants. Importantly, expression of the gene and biosynthesis of siderophores are regulated by NOX, YAP1 and HOG1, supporting a functional link among these regulatory pathways. Although iron fully rescues HO sensitivity seen in mutants impaired for the response regulator SKN7, neither expression of nor biosynthesis of siderophores is controlled by SKN7. Our results indicate that the acquisition of environmental iron has profound effects on ROS detoxification.

Funding
This study was supported by the:
  • Florida Agricultural Experiment Station
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2014-05-01
2024-03-29
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