Premium
Cytosolic NADP‐dependent isocitrate dehydrogenase contributes to redox homeostasis and the regulation of pathogen responses in Arabidopsis leaves
Author(s) -
MHAMDI AMNA,
MAUVE CAROLINE,
GOUIA HOUDA,
SAINDRENAN PATRICK,
HODGES MICHAEL,
NOCTOR GRAHAM
Publication year - 2010
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/j.1365-3040.2010.02133.x
Subject(s) - isocitrate dehydrogenase , biology , arabidopsis , mutant , biochemistry , metabolite , cytosol , dehydrogenase , gene , wild type , arabidopsis thaliana , oxidative stress , enzyme
Cytosolic NADP‐dependent isocitrate dehydrogenase (cICDH) produces 2‐oxoglutarate (2‐OG) and NADPH, and is encoded by a single gene in Arabidopsis thaliana . Three allelic lines carrying T‐DNA insertions in this gene showed less than 10% extractable leaf ICDH activity, but only relatively small decreases in growth compared to wild‐type Col0. Metabolite profiling by gas chromatography–time of flight–mass spectrometry (GC–TOF–MS) and high‐performance liquid chromatography (HPLC) revealed that loss of cICDH function produced only small effects on leaf compounds involved in carbon and nitrogen assimilation. To analyse whether cICDH contributes to NADPH production under conditions of oxidative stress, the icdh mutation was introduced into the cat2 background, in which increased availability of H 2 O 2 causes perturbed redox homeostasis and induction of stress‐related genes. Accumulation of oxidized glutathione and pathogen‐related responses were enhanced in double cat2 icdh mutants compared to cat2 . Single icdh mutants presented constitutive induction of PR genes, and enhanced resistance to bacteria in icdh , cat2 and cat2 icdh was quantitatively correlated with PR gene expression. However, the effect of icdh in both Col0 and cat2 backgrounds was not associated with enhanced accumulation of salicylic acid (SA). The results suggest that cICDH, previously considered mainly as an enzyme involved in amino acid synthesis, plays a role in redox signalling linked to pathogen responses.