title: Glutathione and tryptophan metabolism are required for Arabidopsis immunity during the hypersensitive response to hemibiotrophs.
abstract: The hypersensitive response (HR) is a type of strong immune response found in plants that is accompanied by localized cell death. However, it is unclear how HR can block a broad range of pathogens with different infective modes. In this study, we report that γ-glutamylcysteine synthetase GSH1, which is critical for glutathione biosynthesis, and tryptophan (Trp) metabolism contribute to HR and block development of fungal pathogens with hemibiotrophic infective modes. We found that GSH1 is involved in the penetration2 (PEN2)-based entry control of the nonadapted hemibiotroph Colletotrichum gloeosporioides. However, Arabidopsis mutants specifically defective in entry control terminated further growth of the pathogen in the presence of HR cell death, whereas gsh1 mutants supported pathogen invasive growth in planta, demonstrating the requirement of GSH1 for postinvasive nonhost resistance. Remarkably, on the basis of the phenotypic and metabolic analysis of Arabidopsis mutants defective in Trp metabolism, we showed that biosynthesis of Trp-derived phytochemicals is also essential for resistance to C. gloeosporioides during postinvasive HR. By contrast, GSH1 and these metabolites are likely to be dispensable for the induction of cell death during postinvasive HR. Furthermore, the resistance to Ralstonia solanacearum 1/resistance to Pseudomonas syringae 4 dual Resistance gene-dependent immunity of Arabidopsis to the adapted hemibiotroph shared GSH1 and cytochromes P450 CYP79B2/CYP79B3 with postinvasive nonhost resistance, whereas resistance to P. syringae pv. maculicola 1 and resistance to P. syringae 2-based Resistance gene resistance against bacterial pathogens did not. These data suggest that the synthesis of glutathione and Trp-derived metabolites during HR play crucial roles in terminating the invasive growth of both nonadapted and adapted hemibiotrophs.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Hiruma
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fukunaga
authors.forename: Pawel
authors.initials: P
authors.lastname: Bednarek
authors.forename: Mariola
authors.initials: M
authors.lastname: Pislewska-Bednarek
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Narusaka
authors.forename: Ken
authors.initials: K
authors.lastname: Shirasu
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Takano
mesh_terms: D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000276:immunology / Q000378:metabolism; D016923:Cell Death / Q000276:immunology; D020231:Colletotrichum / Q000276:immunology*; D017931:DNA Primers / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics / Q000276:immunology*; D005838:Genotype; D005721:Glutamate-Cysteine Ligase / Q000276:immunology / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009699:N-Glycosyl Hydrolases / Q000276:immunology / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000276:immunology; D043368:Ralstonia solanacearum / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D017931:DNA Primers; D014364:Tryptophan; D009699:N-Glycosyl Hydrolases; C505663:PEN2 protein, Arabidopsis; D005721:Glutamate-Cysteine Ligase; C493655:Gsh1 protein, Arabidopsis; D005978:Glutathione
keywords: camalexin; hemibiotrophy; indole glucosinolates; mesophyll; tryptophan-derived metabolites