title: Overexpression of Arabidopsis ACBP3 enhances NPR1-dependent plant resistance to Pseudomonas syringe pv tomato DC3000.
abstract: ACBP3 is one of six Arabidopsis (Arabidopsis thaliana) genes, designated ACBP1 to ACBP6, that encode acyl-coenzyme A (CoA)-binding proteins (ACBPs). These ACBPs bind long-chain acyl-CoA esters and phospholipids and are involved in diverse cellular functions, including acyl-CoA homeostasis, development, and stress tolerance. Recombinant ACBP3 binds polyunsaturated acyl-CoA esters and phospholipids in vitro. Here, we show that ACBP3 plays a role in the plant defense response to the bacterial pathogen Pseudomonas syringae pv tomato DC3000. ACBP3 mRNA was up-regulated upon pathogen infection and treatments using pathogen elicitors and defense-related phytohormones. Transgenic Arabidopsis ACBP3 overexpressors (ACBP3-OEs) showed constitutive expression of pathogenesis-related genes (PR1, PR2, and PR5), cell death, and hydrogen peroxide accumulation in leaves. Consequently, ACBP3-OEs displayed enhanced resistance to the bacterial pathogen P. syringae DC3000. In contrast, the acbp3 T-DNA insertional mutant was more susceptible and exhibited lower PR gene transcript levels upon infection. Using the ACBP3 OE-1 line in combination with nonexpressor of PR genes1 (npr1-5) or coronatine-insensitive1 (coi1-2), we concluded that the enhanced PR gene expression and P. syringae DC3000 resistance in the ACBP3-OEs are dependent on the NPR1-mediated, but not the COI1-mediated, signaling pathway. Given that ACBP3-OEs showed greater susceptibility to infection by the necrotrophic fungus Botrytis cinerea while the acbp3 mutant was less susceptible, we suggest that ACBP3 plays a role in the plant defense response against biotrophic pathogens that is distinct from necrotrophic pathogens. ACBP3 function in plant defense was supported further by bioinformatics data showing up-regulation of many biotic and abiotic stress-related genes in ACBP3 OE-1 in comparison with the wild type.
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Xiao
authors.forename: Mee-Len
authors.initials: ML
authors.lastname: Chye
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016718:Arachidonic Acid / Q000494:pharmacology; D020171:Botrytis / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D060467:Disease Resistance / Q000187:drug effects / Q000276:immunology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D055786:Gene Knockout Techniques; D017343:Genes, Plant / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology; D044224:Pseudomonas syringae / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: C513212:ACBP3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C105496:NPR1 protein, Arabidopsis; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D016718:Arachidonic Acid; D006861:Hydrogen Peroxide; D020156:Salicylic Acid