Primary metabolism in plant defense: regulation of a bean malic enzyme gene promoter in transgenic tobacco by developmental and environmental cues

• Published in: Plant physiology (Bethesda) 1995-07, Vol.108 (3), p.949-960
• Main Authors: Schaaf, J. (Universitat Hohenheim, Stuttgart, Germany.), Walter, M.H, Hess, D
• Format: Article
• Language: English
• Subjects: ACIDE ASCORBIQUE; ACIDE MALIQUE; ACIDE PYRUVIQUE; ACIDO ASCORBICO; ACIDO MALICO; ACIDO PIRUVICO; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; AGENT PATHOGENE; AGENTES NOCIVOS; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; ARN MENSAJERO; ARN MESSAGER; Biological and medical sciences; BIOSINTESIS; BIOSYNTHESE; CATALASA; CATALASE; CELLULASE; CELULASA; CITOPLASMA; CODE GENETIQUE; CODIGO GENETICO; COENZIMAS; COENZYME; CYTOPLASME; DIOXIDO DE CARBONO; DIOXYDE DE CARBONE; Enzymes; ETAPAS DE DESARROLLO; EXPRESION GENICA; EXPRESSION DES GENES; FACTEUR NUISIBLE; FLEUR; FLORES; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Regulation and Molecular Genetics; Generalities. Disease free stocks; Genes; GENETICA; GENETIQUE; GLICOSIDASAS; GLUTATHION; GLUTATION; GLYCOSIDASE; Leaves; MECANISME DE DEFENSE; MECANISMOS DE DEFENSA; Messenger RNA; METABOLISME; METABOLISMO; METABOLITE; METABOLITOS; NICOTIANA TABACUM; NUCLEOTIDE; NUCLEOTIDOS; ORGANISMOS PATOGENOS; OXIDACION; OXIDORREDUCTASAS; OXYDATION; OXYDOREDUCTASE; PEROXIDO DE HIDROGENO; PEROXYDE D'HYDROGENE; PHASEOLUS VULGARIS; Phytopathology. Animal pests. Plant and forest protection; PLANTAS TRANSGENICAS; PLANTE TRANSGENIQUE; Plants; REACCIONES QUIMICAS; REACTION CHIMIQUE; RNA; STADE DE DEVELOPPEMENT; Stems; TALLO; TIGE; TRANSFERENCIA DE GENES; TRANSFERT DE GENE; Transgenic plants
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.108.3.949

NADP-dependent malic enzyme (NADP-ME, EC 1.1.1.40) catalyzes the oxidative decarboxylation of malate to pyruvate, producing CO2 and NADPH. We have examined regulatory properties of a 2.8-kb promoter-leader fragment of a bean (Phaseolus vulgaris L.) NADP-ME gene (PvME1) predicted to encode a cytosolic form of the enzyme by expression analysis of promoter-beta-glucuronidase fusions in transgenic tobacco plants. The PvME1 promoter directed strong expression in stems, which was confined to vascular and pith tissues, and was also active in floral and reproductive tissues. Wounding caused a marked induction of promoter activity, which was further strongly enhanced upon application of stimuli related to pathogen defense. Glutathione (reduced form) was the strongest inducer, but oxidized glutathione, fungal elicitor, cellulase, catalase, ascorbic acid, and NADPH were additional potent promoter-stimulating agents. Responsiveness to reduced glutathione was also shown at the level of PvME1 mRNA accumulation in bean plants. The putative contributions of NADP-ME gene expression to the plant defense response and possible mechanisms of defense gene regulation by conditions of oxidative stress as well as by H2O2 and antioxidant levels are discussed