Premium
Salicylic acid‐dependent and ‐independent impact of an RNA ‐binding protein on plant immunity
Author(s) -
HACKMANN CHRISTIAN,
KORNELI CHRISTIN,
KUTYNIOK MAGDALENE,
KÖSTER TINO,
WIEDENLÜBBERT MATTHIAS,
MÜLLER CAROLINE,
STAIGER DOROTHEE
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12188
Subject(s) - salicylic acid , pseudomonas syringae , biology , immunity , rna , systemic acquired resistance , microbiology and biotechnology , transcription (linguistics) , gene expression , immunoprecipitation , gene , biochemistry , immune system , immunology , arabidopsis , mutant , linguistics , philosophy
Plants overexpressing the RNA ‐binding protein AtGRP 7 ( AtGRP7 ‐ox plants) constitutively express the PR ‐1 ( PATHOGENESIS‐RELATED ‐1 ), PR ‐2 and PR ‐5 transcripts associated with salicylic acid ( SA )‐mediated immunity and show enhanced resistance against Pseudomonas syringae pv. tomato ( P to ) DC 3000. Here, we investigated whether the function of AtGRP 7 in plant immunity depends on SA . Endogenous SA was elevated fivefold in AtGRP7 ‐ox plants. The elevated PR ‐1 , PR ‐2 and PR ‐5 levels were eliminated upon expression of the salicylate hydroxylase nah G in AtGRP7 ‐ox plants and elevated PR ‐1 levels were suppressed by sid (salicylic acid deficient) 2‐1 that is impaired in SA biosynthesis. RNA immunoprecipitation showed that AtGRP 7 does not bind the PR ‐1 transcript in vivo , whereas it binds PDF 1.2 . Constitutive or inducible AtGRP 7 overexpression increases PR ‐1 promoter activity, indicating that AtGRP 7 affects PR ‐1 transcription. I n line with this, the effect of AtGRP 7 on PR ‐1 is suppressed by npr (non‐expressor of PR genes) 1. Whereas AtGRP7 ‐ox plants restricted growth of P to DC 3000 compared with wild type (wt), sid2‐1 AtGRP7 ‐ox plants allowed more growth than AtGRP7 ‐ox plants. Furthermore, we show an enhanced hypersensitive response triggered by avirulent P to DC3000 ( A vr R pt2) in AtGRP7 ‐ox compared with wt. I n sid2‐1 AtGRP7 ‐ox, an intermediate phenotype was observed. Thus, AtGRP 7 has both SA ‐dependent and SA ‐independent effects on plant immunity.