Molecular Plant Pathology - 2023 - Zhang - High‐affinity iron uptake is required for optimal Epichlo festucae colonization.pdf (3.31 MB)

High‐affinity iron uptake is required for optimal Epichloë festucae colonization of Lolium perenne and seed transmission

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posted on 2023-12-18, 02:52 authored by Wei ZhangWei Zhang, Tash ForesterTash Forester, Emma Applegate, Xinqi (Leo) LiuXinqi (Leo) Liu, Linda JohnsonLinda Johnson

Epichloë festucae uses a siderophore-mediated system to acquire iron, which is important to maintain endophyte–grass symbioses. Here we investigate the roles of the alternative iron acquisition system, reductive iron assimilation (RIA), via disruption of the fetC gene, which encodes a multicopper ferroxidase, either alone (i.e., ΔfetC) or in combination with disruption of the gene sidA, which encodes a siderophore biosynthesis enzyme (i.e., ΔfetCsidA). The phenotypic characteristics of these mutants were compared to ΔsidA and wild-type (WT) strains during growth under axenic culture conditions (in culture) and in symbiosis with the host grass, perennial ryegrass (in planta). Under iron deficiency, the colony growth rate of ΔfetC was slightly slower than that of WT, while the growth of ΔsidA and ΔfetCsidA mutants was severely suppressed. Siderophore analyses indicated that ΔfetC mutants hyperaccumulate ferriepichloënin A (FEA) at low iron concentrations and ferricrocin and FEA at higher iron concentrations. When compared to WT, all mutant strains displayed hyperbranching hyphal structures and a reduced ratio of Epichloë DNA to total DNA in planta. Furthermore, host colonization and vertical transmission through infection of the host seed were significantly reduced in the ΔfetCsidA mutants, confirming that high-affinity iron uptake is a critical process for Epichloë transmission. Thus, RIA and siderophore iron uptake are complementary systems required for the maintenance of iron metabolism, fungal growth, and symbiosis between E. festucae and perennial ryegrass.


MBIE Strategic Science Investment Fund (SSIF) Grant Number A20067


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© 2023 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Jon Wiley & Sons Ltd

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Molecular Plant Pathology



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