title: Loss of cytosolic NADP-malic enzyme 2 in Arabidopsis thaliana is associated with enhanced susceptibility to Colletotrichum higginsianum.
abstract: • 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.
authors.affiliation: Division of Biochemistry, Department of Biology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Lars M
authors.initials: LM
authors.lastname: Voll
authors.forename: Martina B
authors.initials: MB
authors.lastname: Zell
authors.forename: Timo
authors.initials: T
authors.lastname: Engelsdorf
authors.forename: Alexandra
authors.initials: A
authors.lastname: Saur
authors.forename: Mariel Gerrard
authors.initials: MG
authors.lastname: Wheeler
authors.forename: Maria F
authors.initials: MF
authors.lastname: Drincovich
authors.forename: Andreas P M
authors.initials: AP
authors.lastname: Weber
authors.forename: Veronica G
authors.initials: VG
authors.lastname: Maurino
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020231:Colletotrichum / Q000472:pathogenicity*; D003600:Cytosol / Q000378:metabolism; D004198:Disease Susceptibility; D018506:Gene Expression Regulation, Plant; D056726:Genetic Association Studies; D005816:Genetic Complementation Test; D005936:Glucans / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000201:enzymology / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D000094162:Phytoalexins
chemical_list: D029681:Arabidopsis Proteins; D005936:Glucans; D007211:Indoles; D008291:Malate Dehydrogenase; D017382:Reactive Oxygen Species; D020156:Salicylic Acid; D013844:Thiazoles; C102405:camalexin; D000094162:Phytoalexins; C048306:callose; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)