Loss of cytosolic NADP-malic enzyme 2 in Arabidopsis is associated with enhanced susceptibility towards Colletotrichum higginsianum

VOLL LM; ZELL, MARTINA; ENGELSDORF T; SAUR A; MARIEL GERRARD WHEELER; MARIA FABIANA DRINCOVICH; WEBER A; MAURINO, VERÓNICA G

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2012 vol. 195 p. 189 - 202

0028-646X

While photosynthetic NADP-malic enzyme (NADP-ME) has a prominent role in the C4 cycle, the biological function of non-photosynthetic isoforms remains elusive. Here, we analysed the link between Arabidopsis thaliana cytosolic NADP-ME2 with plant defence responses. A. thaliana plants with wild-type and modified NADP-ME2 expression levels were analysed after elicitation with pathogen-associated molecular patterns (PAMPs) and in the interaction with the hemibiotrophic fungal pathogen Colletotrichum higginsianum. Under normal growth conditions, the lack of or the gain of NADP-ME2 activity produces large changes in plant metabolite pool sizes without any effect on morphology or development. Total NADP-ME activity was enhanced after PAMP treatment and pathogen infection due to transcriptional induction of the NADP-ME2 gene. During infection with C. higginsianum, loss-of function mutants of NADP-ME2 (nadp-me2) showed enhanced susceptibility. Transient apoplastic reactive oxygen species production after elicitation and callose-papillae formation after infection were dampened in nadp-me2. Late SA-dependent and SA-independent defence responses were not affected. Altogether, our results indicate that NADP-ME2 is an important player in plant basal defence, where it appears to be required for the oxidative burst. Moreover, NADP-ME2 was found to be dispensable for later defence responses