TmpL, a Transmembrane Protein Required for Intracellular Redox Homeostasis and Virulence in a Plant and an Animal Fungal Pathogen

PLoS Pathogens

Yangrae Cho¹  Srisombat Puttikamonkul²  Robert A. Cramer Jr.²  Nora Grahl²  Sven D. Willger²  Kwang-Hyung Kim³  Sang-Wook Park³  Christopher B. Lawrence³  Biswarup Mukhopadhyay³ 

[1] Department of Plant and Environmental Protection Sciences, University of Hawaii, Honolulu, Hawaii, United States of America;Department of Veterinary Molecular Biology, Montana State University, Bozeman, Montana, United States of America;Virginia Bioinformatics Institute and Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America

关键词: Aspergillus fumigatus;    Plant fungal pathogens;    Appressoria;    Polymerase chain reaction;    Oxidative stress;    Fungal pathogens;    Fungal genetics;    Fungi;   

DOI  :  10.1371/journal.ppat.1000653

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The regulation of intracellular levels of reactive oxygen species (ROS) is critical for developmental differentiation and virulence of many pathogenic fungi. In this report we demonstrate that a novel transmembrane protein, TmpL, is necessary for regulation of intracellular ROS levels and tolerance to external ROS, and is required for infection of plants by the necrotroph Alternaria brassicicola and for infection of mammals by the human pathogen Aspergillus fumigatus. In both fungi, tmpL encodes a predicted hybrid membrane protein containing an AMP-binding domain, six putative transmembrane domains, and an experimentally-validated FAD/NAD(P)-binding domain. Localization and gene expression analyses in A. brassicicola indicated that TmpL is associated with the Woronin body, a specialized peroxisome, and strongly expressed during conidiation and initial invasive growth in planta. A. brassicicola and A. fumigatus ΔtmpL strains exhibited abnormal conidiogenesis, accelerated aging, enhanced oxidative burst during conidiation, and hypersensitivity to oxidative stress when compared to wild-type or reconstituted strains. Moreover, A. brassicicola ΔtmpL strains, although capable of initial penetration, exhibited dramatically reduced invasive growth on Brassicas and Arabidopsis. Similarly, an A. fumigatus ΔtmpL mutant was dramatically less virulent than the wild-type and reconstituted strains in a murine model of invasive aspergillosis. Constitutive expression of the A. brassicicola yap1 ortholog in an A. brassicicola ΔtmpL strain resulted in high expression levels of genes associated with oxidative stress tolerance. Overexpression of yap1 in the ΔtmpL background complemented the majority of observed developmental phenotypic changes and partially restored virulence on plants. Yap1-GFP fusion strains utilizing the native yap1 promoter exhibited constitutive nuclear localization in the A. brassicicola ΔtmpL background. Collectively, we have discovered a novel protein involved in the virulence of both plant and animal fungal pathogens. Our results strongly suggest that dysregulation of oxidative stress homeostasis in the absence of TmpL is the underpinning cause of the developmental and virulence defects observed in these studies.

【 授权许可】

CC BY