title: Activation of NADPH-recycling systems in leaves and roots of Arabidopsis thaliana under arsenic-induced stress conditions is accelerated by knock-out of Nudix hydrolase 19 (AtNUDX19) gene.
abstract: NADPH is an important cofactor in cell growth, proliferation and detoxification. Arabidopsis thaliana Nudix hydrolase 19 (AtNUDX19) belongs to a family of proteins defined by the conserved amino-acid sequence GX5-EX7REUXEEXGU which has the capacity to hydrolyze NADPH as a physiological substrate in vivo. Given the importance of NADPH in the cellular redox homeostasis of plants, the present study compares the responses of the main NADPH-recycling systems including NADP-isocitrate dehydrogenase (ICDH), glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH) and NADP-malic enzyme (ME) in the leaves and roots of Arabidopsis wild-type (Wt) and knock-out (KO) AtNUDX19 mutant (Atnudx19) plants under physiological and arsenic-induced stress conditions. Two major features were observed in the behavior of the main NADPH-recycling systems: (i) under optimal conditions in both organs, the levels of these activities were higher in nudx19 mutants than in Wt plants; and, (ii) under 500μM AsV conditions, these activities increase, especially in nudx19 mutant plants. Moreover, G6PDH activity in roots was the most affected enzyme in both Wt and nudx19 mutant plants, with a 4.6-fold and 5.0-fold increase, respectively. In summary, the data reveals a connection between the absence of chloroplastic AtNUDX19 and the rise in all NADP-dehydrogenase activities under physiological and arsenic-induced stress conditions, particularly in roots. This suggests that AtNUDX19 could be a key factor in modulating the NADPH pool in plants and consequently in redox homeostasis.
authors.affiliation: Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Granada, Spain. Electronic address: javier.corpas@eez.csic.es.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Corpas
authors.affiliation: Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Granada, Spain.
authors.forename: Simeón
authors.initials: S
authors.lastname: Aguayo-Trinidad
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Department of Food and Nutritional Science, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yoshimura
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001151:Arsenic / Q000009:adverse effects; D055786:Gene Knockout Techniques; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis; D007521:Isocitrate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009249:NADP / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011755:Pyrophosphatases / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects; D000096964:Nudix Hydrolases
chemical_list: D029681:Arabidopsis Proteins; D001151:Arsenic; D005954:Glucosephosphate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D008291:Malate Dehydrogenase; D009249:NADP; D009252:NADPH Dehydrogenase; D010734:Phosphogluconate Dehydrogenase; D011755:Pyrophosphatases; D000096964:Nudix Hydrolases; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+); C039355:isocitrate dehydrogenase (NADP+)
keywords: 6PGDH; Arsenic; AtNUDX19; G6PDH; NADP-ICDH; NADP-ME; NADPH; Oxidative stress