Activation of R‐mediated innate immunity and disease susceptibility is affected by mutations in a cytosolic O‐acetylserine (thiol) lyase in Arabidopsis. (5th November 2012)

• Record Type: Journal Article
• Authors: Tahir, Jibran; Watanabe, Mutsumi; Jing, Hai‐Chun; Hunter, Donald A.; Tohge, Takayuki; Nunes‐Nesi, Adriano; Brotman, Yariv; Fernie, Alisdair R.; Hoefgen, Rainer; Dijkwel, Paul P.
• Is Part Of: Plant journal. Volume 73:Number 1(2013:Jan.)
• Page Start: 118
• Page End: 130
• Publication Date: 2012-11-05
• Subjects: RPP1 -- OASTL‐A1 -- disease resistance -- auto‐necrosis -- cysteine biosynthesis -- innate immunity; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12021
• Languages: English
• ISSNs: 0960-7412

Abstract

Summary: O ‐acetylserine (thiol) lyases (OASTLs) are evolutionarily conserved proteins among many prokaryotes and eukaryotes that perform sulfur acquisition and synthesis of cysteine. A mutation in the cytosolic OASTL‐A1 protein ONSET OF LEAF DEATH3 (OLD3) was previously shown to reduce the OASTL activity of the old3‐1 protein in vitro and cause auto‐necrosis in specific Arabidopsis accessions. Here we investigated why a mutation in this protein causes auto‐necrosis in some but not other accessions. The auto‐necrosis was found to depend on Recognition of Peronospora Parasitica 1 ( RPP1 )‐like disease resistance R gene(s) from an evolutionarily divergent R gene cluster that is present in L er ‐0 but not the reference accession Col‐0. RPP1 ‐ like gene(s) show a negative epistatic interaction with the old3 ‐ 1 mutation that is not linked to reduced cysteine biosynthesis. Metabolic profiling and transcriptional analysis further indicate that an effector triggered‐like immune response and metabolic disorder are associated with auto‐necrosis in old3 ‐ 1 mutants, probably activated by an RPP1 ‐ like gene. However, the old3‐1 protein in itself results in largely neutral changes in primary plant metabolism, stress defence and immune responses. Finally, we showed that lack of a functional OASTL‐A1 results in enhanced disease susceptibility against infection with virulent and non‐virulent Pseudomonas syringae pv. tomato DC3000 strains. These results reveal an interaction between the cytosolic OASTL and components of plant immunity.