title: Salicyloyl-aspartate synthesized by the acetyl-amido synthetase GH3.5 is a potential activator of plant immunity in Arabidopsis.
abstract: Salicylic acid (SA) plays a critical role in plant immunity responses against pathogen infection, especially in the establishment of systemic acquired resistance. Whether other forms of salicylates also function in plant immunity has not been explored. Our previous study has revealed that salicyloyl-aspartate (SA-Asp), the only reported endogenous SA-amino acid conjugate in plants, was highly accumulated in the Arabidopsis activation-tagged mutant gh3.5-1D after pathogen infection. In this study, we dissected SA-Asp production in Arabidopsis. In vitro biochemical experiments showed that the GH3.5 protein could catalyze the conjugation of SA with aspartic acid to form SA-Asp. SA-Asp is not converted into free SA and likely acts as a mobile molecule in plants. SA-Asp could induce pathogenesis-related (PR) gene expression and increase disease resistance to pathogenic Pseudomonas syringae. Our current study also supports the notion that GH3.5 is a multifunction enzyme in plant hormone metabolism.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Shen
authors.forename: Muyang
authors.initials: M
authors.lastname: Wang
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: Zuhua
authors.initials: Z
authors.lastname: He
mesh_terms: D017360:Arabidopsis / Q000276:immunology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D008025:Ligases / Q000378:metabolism*; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity / Q000187:drug effects*; D044224:Pseudomonas syringae / Q000472:pathogenicity; D012459:Salicylates / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D012459:Salicylates; D001224:Aspartic Acid; C525277:GH3.5 protein, Arabidopsis; D008025:Ligases
keywords: Arabidopsis; GH3.5; plant immunity; salicyloyl-aspartate