Role of hydrogen peroxide during the interaction between the hemibiotrophic fungal pathogen Septoria tritici and wheat

• Published in: The New phytologist Vol. 174; no. 3; pp. 637 - 647
• Main Authors: Shetty, Nandini P, Mehrabi, Rahim, Lütken, Henrik, Haldrup, Anna, Kema, Gert H.J, Collinge, David B, Jørgensen, Hans Jørgen Lyngs
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.01.2007; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Ascomycota - genetics; Ascomycota - metabolism; carbohydrate-metabolism; Carbohydrates - analysis; Catalase - metabolism; Chlorophyll - analysis; Chlorophylls; disease resistance; DNA, Fungal; Gene Expression Regulation, Plant; h2o2 accumulation; hemibiotrophic; Hydrogen; hydrogen peroxide (H2O2); hydrogen peroxide (H₂O₂); Hydrogen Peroxide - metabolism; hypersensitive response; Infections; Inoculation; Mycosphaerella graminicola; oxidative stress; Pathogens; pea leaves; Peroxides; Photosynthesis; Plant Diseases - microbiology; Plant Leaves - chemistry; Plant Leaves - metabolism; Plants; powdery mildew interaction; Septoria tritici; signal-transduction pathways; Stomata; stress; Sugars; Triticum - chemistry; Triticum - metabolism; Triticum - microbiology; Triticum aestivum; wheat; wheat (Triticum aestivum)
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2007.02026.x

Hydrogen peroxide (H₂O₂) is reported to inhibit biotrophic but benefit necrotrophic pathogens. Infection by necrotrophs can result in a massive accumulation of H₂O₂ in hosts. Little is known of how pathogens with both growth types are affected (hemibiotrophs). The hemibiotroph, Septoria tritici, infecting wheat (Triticum aestivum) is inhibited by H₂O₂ during the biotrophic phase, but a large H₂O₂ accumulation occurs in the host during reproduction. Here, we infiltrated catalase, H₂O₂ or water into wheat during the biotrophic or the necrotrophic phase of S. tritici and studied the effect of infection on host physiology to get an understanding of the survival strategy of the pathogen. H₂O₂ removal by catalase at both early and late stages made plants more susceptible, whereas H₂O₂ made them more resistant. H₂O₂ is harmful to S. tritici throughout its life cycle, but it can be tolerated. The late accumulation of H₂O₂ is unlikely to result from down-regulation of photosynthesis, but probably originates from damage to the peroxisomes during the general tissue collapse, which is accompanied by release of soluble sugars in a susceptible cultivar.