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

New Phytol. 2012 Jul;195(1):189-202. doi: 10.1111/j.1469-8137.2012.04129.x. Epub 2012 Apr 12.


• While photosynthetic NADP-malic enzyme (NADP-ME) has a prominent role in the C(4) cycle, the biological function of nonphotosynthetic isoforms remains elusive. Here, we analysed the link between Arabidopsis thaliana cytosolic NADP-ME2 and the plant defence response. • Arabidopsis thaliana plants with wild-type and modified NADP-ME2 expression levels were analysed after elicitation with pathogen-associated molecular patterns (PAMPs) and during the interaction with the hemibiotrophic fungal pathogen Colletotrichum higginsianum. • Under normal growth conditions, the lack or gain of NADP-ME2 activity produced large changes in plant metabolite pool sizes without any effect on morphology or development. Total NADP-ME activity and NADP-ME2 transcript level were enhanced after PAMP treatment and pathogen infection. During infection with C. higginsianum, loss-of-function mutants of NADP-ME2 (nadp-me2) showed enhanced susceptibility. Transient apoplastic reactive oxygen species (ROS) production after elicitation and callose papilla formation after infection were dampened in nadp-me2. Late salicylic acid (SA)-dependent and SA-independent defence responses were not affected. • Taken together, our results indicate that NADP-ME2 is an important player in plant basal defence, where it appears to be involved in the generation of ROS. Moreover, NADP-ME2 was found to be dispensable for later defence responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / microbiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Colletotrichum / pathogenicity*
  • Cytosol / metabolism
  • Disease Susceptibility
  • Gene Expression Regulation, Plant
  • Genetic Association Studies
  • Genetic Complementation Test
  • Glucans / metabolism
  • Indoles / metabolism
  • Malate Dehydrogenase / genetics
  • Malate Dehydrogenase / metabolism*
  • Mutation
  • Plant Diseases / microbiology
  • Plant Leaves / enzymology
  • Plant Leaves / microbiology
  • Reactive Oxygen Species / metabolism
  • Salicylic Acid / metabolism
  • Thiazoles / metabolism


  • Arabidopsis Proteins
  • Glucans
  • Indoles
  • Reactive Oxygen Species
  • Thiazoles
  • camalexin
  • callose
  • Malate Dehydrogenase
  • malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)
  • Salicylic Acid