Journal Article

Hydrogen Peroxide Acts on Sensitive Mitochondrial Proteins to Induce Death of a Fungal Pathogen Revealed by Proteomic Analysis

Cao, Baohua, Tian, Shiping, Qin, Guozheng, Liu, Jia, Li, Boqiang

2011

Overview

How the host cells of plants and animals protect themselves against fungal invasion is a biologically interesting and economically important problem. Here we investigate the mechanistic process that leads to death of Penicillium expansum, a widespread phytopathogenic fungus, by identifying the cellular compounds affected by hydrogen peroxide (H(2)O(2)) that is frequently produced as a response of the host cells. We show that plasma membrane damage was not the main reason for H(2)O(2)-induced death of the fungal pathogen. Proteomic analysis of the changes of total cellular proteins in P. expansum showed that a large proportion of the differentially expressed proteins appeared to be of mitochondrial origin, implying that mitochondria may be involved in this process. We then performed mitochondrial sub-proteomic analysis to seek the H(2)O(2)-sensitive proteins in P. expansum. A set of mitochondrial proteins were identified, including respiratory chain complexes I and III, F(1)F(0) ATP synthase, and mitochondrial phosphate carrier protein. The functions of several proteins were further investigated to determine their effects on the H(2)O(2)-induced fungal death. Through fluorescent co-localization and the use of specific inhibitor, we provide evidence that complex III of the mitochondrial respiratory chain contributes to ROS generation in fungal mitochondria under H(2)O(2) stress. The undesirable accumulation of ROS caused oxidative damage of mitochondrial proteins and led to the collapse of mitochondrial membrane potential. Meanwhile, we demonstrate that ATP synthase is involved in the response of fungal pathogen to oxidative stress, because inhibition of ATP synthase by oligomycin decreases survival. Our data suggest that mitochondrial impairment due to functional alteration of oxidative stress-sensitive proteins is associated with fungal death caused by H(2)O(2).

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adenosine Triphosphate - metabolism / Amino Acid Sequence / Analysis / Apoptosis / ATP / ATP synthase / Biology / Candida albicans / Cell Membrane - drug effects / Cell Membrane - metabolism / Cellular proteins / Chains / Cryptococcus laurentii / Damage accumulation / Death / Developmental biology / Economic importance / Electron transport / Electron Transport Complex III - metabolism / Enzymes / Fluorescence / Fungal Proteins - chemistry / Fungal Proteins - metabolism / Fungi / Host plants / Hydrogen / Hydrogen peroxide / Hydrogen Peroxide - pharmacology / Intracellular Space - drug effects / Intracellular Space - metabolism / Investigations / Laboratories / Localization / Mass spectrometry / Membrane potential / Membrane Potential, Mitochondrial - drug effects / Microbial Viability - drug effects / Mitochondria / Mitochondria - drug effects / Mitochondria - enzymology / Mitochondrial Proteins - chemistry / Mitochondrial Proteins - metabolism / Mitochondrial Proton-Translocating ATPases - metabolism / Molecular Sequence Data / Mortality / Oligomycin / Oxidative stress / Oxidative Stress - drug effects / Pathogens / Penicillium - cytology / Penicillium - drug effects / Penicillium expansum / Phosphates / Photodynamic therapy / Photosynthesis / Physiology / Phytopathogenic fungi / Plant cells / Plant protection / Plants (botany) / Protein synthesis / Proteins / Proteomics - methods / Reactive oxygen species / Scientific imaging / Time Factors / Wildlife conservation