Premium
Constitutive salicylic acid accumulation in pi4k III β1β2 Arabidopsis plants stunts rosette but not root growth
Author(s) -
Šašek Vladimír,
Janda Martin,
Delage Elise,
Puyaubert Juliette,
Guivarc'h Anne,
López Maseda Encarnación,
Dobrev Petre I.,
Caius José,
Bóka Károly,
Valentová Olga,
Burketová Lenka,
Zachowski Alain,
Ruelland Eric
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12822
Subject(s) - biology , mutant , rosette (schizont appearance) , microbiology and biotechnology , phenotype , gene , genetics , arabidopsis , immunology
Summary Phospholipids have recently been found to be integral elements of hormone signalling pathways. An Arabidopsis thaliana double mutant in two type III phosphatidylinositol‐4‐kinases ( PI 4Ks), pi4k III β1β2 , displays a stunted rosette growth. The causal link between PI 4K activity and growth is unknown. Using microarray analysis, quantitative reverse transcription polymerase chain reaction (RT‐ qPCR ) and multiple phytohormone analysis by LC‐MS we investigated the mechanism responsible for the pi4kIIIβ1β2 phenotype. The pi4k III β1β2 mutant accumulated a high concentration of salicylic acid ( SA ), constitutively expressed SA marker genes including PR ‐1 , and was more resistant to Pseudomonas syringae . pi4k III β1β2 was crossed with SA signalling mutants eds1 and npr1 and SA biosynthesis mutant sid2 and NahG . The dwarf phenotype of pi4k III β1β2 rosettes was suppressed in all four triple mutants. Whereas eds1 pi4k III β1β2 , sid2 pi4k III β1β2 and NahG pi4k III β1β2 had similar amounts of SA as the wild‐type ( WT ), npr1pi4k III β1β2 had more SA than pi4k III β1β2 despite being less dwarfed. This indicates that PI 4 KIII β1 and PI 4 KIII β2 are genetically upstream of EDS 1 and need functional SA biosynthesis and perception through NPR 1 to express the dwarf phenotype. The slow root growth phenotype of pi4k III β1β2 was not suppressed in any of the triple mutants. The pi4k III β1β2 mutations together cause constitutive activation of SA signalling that is responsible for the dwarf rosette phenotype but not for the short root phenotype.