title: Pepper aldehyde dehydrogenase CaALDH1 interacts with Xanthomonas effector AvrBsT and promotes effector-triggered cell death and defence responses.
abstract: Xanthomonas type III effector AvrBsT induces hypersensitive cell death and defence responses in pepper (Capsicum annuum) and Nicotiana benthamiana. Little is known about the host factors that interact with AvrBsT. Here, we identified pepper aldehyde dehydrogenase 1 (CaALDH1) as an AvrBsT-interacting protein. Bimolecular fluorescence complementation and co-immunoprecipitation assays confirmed the interaction between CaALDH1 and AvrBsT in planta. CaALDH1:smGFP fluorescence was detected in the cytoplasm. CaALDH1 expression in pepper was rapidly and strongly induced by avirulent Xanthomonas campestris pv. vesicatoria (Xcv) Ds1 (avrBsT) infection. Transient co-expression of CaALDH1 with avrBsT significantly enhanced avrBsT-triggered cell death in N. benthamiana leaves. Aldehyde dehydrogenase activity was higher in leaves transiently expressing CaALDH1, suggesting that CaALDH1 acts as a cell death enhancer, independently of AvrBsT. CaALDH1 silencing disrupted phenolic compound accumulation, H2O2 production, defence response gene expression, and cell death during avirulent Xcv Ds1 (avrBsT) infection. Transgenic Arabidopsis thaliana overexpressing CaALDH1 exhibited enhanced defence response to Pseudomonas syringae pv. tomato and Hyaloperonospora arabidopsidis infection. These results indicate that cytoplasmic CaALDH1 interacts with AvrBsT and promotes plant cell death and defence responses.
authors: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
authors: Nak Hyun
authors: NH
authors: Kim
authors: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea bkhwang@korea.ac.kr.
authors: Byung Kook
authors: BK
authors: Hwang
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002212:Capsicum / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000502:physiology; D016923:Cell Death; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D009868:Oomycetes / Q000502:physiology; D010935:Plant Diseases / Q000276:immunology*; D057865:Plant Immunity; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000502:physiology; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000502:physiology; D016959:Xanthomonas campestris / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D006861:Hydrogen Peroxide; D000444:Aldehyde Dehydrogenase
keywords: Aldehyde dehydrogenase; Xanthomonas campestris pv. vesicatoria.; cell death; effector AvrBsT; pepper; plant defence