title: Transformation of plum plants with a cytosolic ascorbate peroxidase transgene leads to enhanced water stress tolerance.
abstract: Water deficit is the most serious environmental factor limiting agricultural production. In this work, the tolerance to water stress (WS) of transgenic plum lines harbouring transgenes encoding cytosolic antioxidant enzymes was studied, with the aim of achieving the durable resistance of commercial plum trees.
  
  
  
  The acclimatization process was successful for two transgenic lines: line C3-1, co-expressing superoxide dismutase (two copies) and ascorbate peroxidase (one copy) transgenes simultaneously; and line J8-1, harbouring four copies of the cytosolic ascorbate peroxidase gene (cytapx). Plant water relations, chlorophyll fluorescence and the levels of antioxidant enzymes were analysed in both lines submitted to moderate (7 d) and severe (15 d) WS conditions. Additionally, in line J8-1, showing the best response in terms of stress tolerance, a proteomic analysis and determination of the relative gene expression of two stress-responsive genes were carried out.
  
  
  
  Line J8-1 exhibited an enhanced stress tolerance that correlated with better photosynthetic performance and a tighter control of water-use efficiency. Furthermore, this WS tolerance also correlated with a higher enzymatic antioxidant capacity than wild-type (WT) and line C3-1 plum plants. On the other hand, line C3-1 displayed an intermediate phenotype between WT plants and line J8-1 in terms of WS tolerance. Under severe WS, the tolerance displayed by J8-1 plants could be due to an enhanced capacity to cope with drought-induced oxidative stress. Moreover, proteomic analysis revealed differences between WT and J8-1 plants, mainly in terms of the abundance of proteins related to carbohydrate metabolism, photosynthesis, antioxidant defences and protein fate.
  
  
  
  The transformation of plum plants with cytapx has a profound effect at the physiological, biochemical, proteomic and genetic levels, enhancing WS tolerance. Although further experiments under field conditions will be required, it is proposed that J8-1 plants would be an interesting Prunus rootstock for coping with climate change.
authors.affiliation: Group of Fruit Trees Biotechnology, Department of Plant Breeding, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain pdv@cebas.csic.es.
authors.forename: Pedro
authors.initials: P
authors.lastname: Diaz-Vivancos
authors.affiliation: Group of Fruit Trees Biotechnology, Department of Plant Breeding, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain.
authors.forename: Lydia
authors.initials: L
authors.lastname: Faize
authors.affiliation: Departamento de Riego, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Nicolás
authors.affiliation: Group of Fruit Trees Biotechnology, Department of Plant Breeding, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain Grupo de Biología de las Plantas en Condiciones Mediterráneas, Departament de Biologia (UIB-IMEDEA), Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Clemente-Moreno
authors.affiliation: Grupo de Proteómica y Genómica Funcional de Plantas, Departamento de Agroquímica y Bioquímica, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain.
authors.forename: Roque
authors.initials: R
authors.lastname: Bru-Martinez
authors.affiliation: Group of Fruit Trees Biotechnology, Department of Plant Breeding, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Burgos
authors.affiliation: Group of Fruit Trees Biotechnology, Department of Plant Breeding, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, PO Box 164, E-30100, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Hernández
mesh_terms: D000064:Acclimatization; D000975:Antioxidants / Q000378:metabolism; D060387:Ascorbate Peroxidases / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll; D003600:Cytosol / Q000201:enzymology; D055864:Droughts; D004798:Enzymes / Q000235:genetics / Q000378:metabolism; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D000068242:Prunus domestica / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013312:Stress, Physiological / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004798:Enzymes; D010940:Plant Proteins; D002734:Chlorophyll; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase
keywords: Antioxidative metabolism; Prunus domestica; cytosolic ascorbate peroxidase; cytosolic superoxide dismutase; drought; genetic engineering; stress tolerance