title: HDA19 is required for the repression of salicylic acid biosynthesis and salicylic acid-mediated defense responses in Arabidopsis.
abstract: To cope with a lifetime of exposure to a variety of pathogens, plants have developed exquisite and refined defense mechanisms that vary depending on the type of attacking pathogen. Defense-associated transcriptional reprogramming is a central part of plant defense mechanisms. Chromatin modification has recently been shown to be another layer of regulation for plant defense mechanisms. Here, we show that the RPD3/HDA1-class histone deacetylase HDA19 is involved in the repression of salicylic acid (SA)-mediated defense responses in Arabidopsis. Loss of HDA19 activity increased SA content and increased the expression of a group of genes required for accumulation of SA as well as pathogenesis related (PR) genes, resulting in enhanced resistance to Pseudomonas syringae. We found that HDA19 directly associates with and deacetylates histones at the PR1 and PR2 promoters. Thus, our study shows that HDA19, by modifying chromatin to a repressive state, ensures low basal expression of defense genes, such as PR1, under unchallenged conditions, as well as their proper induction without overstimulation during defense responses to pathogen attacks. Thus, the role of HDA19 might be critical in preventing unnecessary activation and self-destructive overstimulation of defense responses, allowing successful growth and development.
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Sun-Mee
authors.initials: SM
authors.lastname: Choi
authors.forename: Hae-Ryong
authors.initials: HR
authors.lastname: Song
authors.forename: Soon-Ki
authors.initials: SK
authors.lastname: Han
authors.forename: Muho
authors.initials: M
authors.lastname: Han
authors.forename: Chi-Yeol
authors.initials: CY
authors.lastname: Kim
authors.forename: Jaejin
authors.initials: J
authors.lastname: Park
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Lee
authors.forename: Jong-Seong
authors.initials: JS
authors.lastname: Jeon
authors.forename: Yoo-Sun
authors.initials: YS
authors.lastname: Noh
authors.forename: Bosl
authors.initials: B
authors.lastname: Noh
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060467:Disease Resistance; D018506:Gene Expression Regulation, Plant; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D011401:Promoter Regions, Genetic; D044224:Pseudomonas syringae / Q000472:pathogenicity; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C507152:HDA19 protein, Arabidopsis; D006655:Histone Deacetylases; D020156:Salicylic Acid