title: The Ralstonia solanacearum type III effector RipAY targets plant redox regulators to suppress immune responses.
abstract: The subversion of plant cellular functions is essential for bacterial pathogens to proliferate in host plants and cause disease. Most bacterial plant pathogens employ a type III secretion system to inject type III effector (T3E) proteins inside plant cells, where they contribute to the pathogen-induced alteration of plant physiology. In this work, we found that the Ralstonia solanacearum T3E RipAY suppresses plant immune responses triggered by bacterial elicitors and by the phytohormone salicylic acid. Further biochemical analysis indicated that RipAY associates in planta with thioredoxins from Nicotiana benthamiana and Arabidopsis. Interestingly, RipAY displays γ-glutamyl cyclotransferase (GGCT) activity to degrade glutathione in plant cells, which is required for the reported suppression of immune responses. Given the importance of thioredoxins and glutathione as major redox regulators in eukaryotic cells, RipAY activity may constitute a novel and powerful virulence strategy employed by R. solanacearum to suppress immune responses and potentially alter general redox signalling in host cells.
authors: Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.|CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors: Yuying
authors: Y
authors: Sang
authors: Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.|CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors: Yaru
authors: Y
authors: Wang
authors: Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.
authors: Hong
authors: H
authors: Ni
authors: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan 31326, France.
authors: Anne-Claire
authors: AC
authors: Cazalé
authors: Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.
authors: Yi-Min
authors: YM
authors: She
authors: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan 31326, France.
authors: Nemo
authors: N
authors: Peeters
authors: Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China.|CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors: Alberto P
authors: AP
authors: Macho
mesh_terms: D017360:Arabidopsis / Q000276:immunology* / Q000382:microbiology; D001426:Bacterial Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D059828:Plant Cells / Q000378:metabolism; D057865:Plant Immunity; D043368:Ralstonia solanacearum / Q000378:metabolism* / Q000472:pathogenicity; D013879:Thioredoxins / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology / Q000276:immunology* / Q000382:microbiology; D000069296:Type III Secretion Systems / Q000378:metabolism*; D014774:Virulence; D005722:gamma-Glutamylcyclotransferase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D000069296:Type III Secretion Systems; D049452:Green Fluorescent Proteins; D013879:Thioredoxins; D005722:gamma-Glutamylcyclotransferase; D005978:Glutathione; D003545:Cysteine
keywords: Ralstonia; glutathione; plant immunity; redox; thioredoxin; type III effector