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Responses to water withdrawal of tobacco plants genetically engineered with the AtTPS1 gene: a special reference to photosynthetic parameters |
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| Authors: | André M Almeida Anabela B Silva Susana S Araújo Luís A Cardoso Dulce M Santos José M Torné Jorge M Silva Matthew J Paul Pedro S Fevereiro |
| Institution: | 1. Laboratório de Biotecnologia de Células Vegetais, Instituto de Tecnologia Química e Biológica (ITQB), Apartado 127 Av. da República (E.A.N.), 2781-901, Oeiras, Portugal 2. Instituto de Investiga??o Científica e Tropical, Lisboa, Portugal 3. Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa (FCUL), Lisboa, Portugal and Centro de Engenharia Biológica (FCUL), Lisboa, Portugal 4. Instituto de Biologia Molecular de Barcelona-CSIC, Barcelona, Spain 5. Crop Performance and Improvement, IACR-Rothamstead, Harpenden, UK |
| Abstract: | We have previously obtained several lines of tobacco transformed with a trehalose-6-phosphate synthase gene of plant origin (Arabidopsis thaliana), involved in the first step of the biosynthesis of trehalose, a known osmoprotectant. Two showed distinct intensity of expression: high (B5H) and low (B1F). Such lines were analyzed for trehalose-6-phosphate content and the obtained results demonstrated to be in accordance with the expression results. In order to study the responses of photosynthesis to water deficit of transgenic lines in comparison to wild type (WT), three experiments were performed under different conditions: (1) Relative water (2) Leaf gas exchange (3) Modulated Chlorophyll a Fluorescence. Different responses in RWC of plant lines to water withdrawal were detected, with transgenic line B5H indicating less water loss after the water withdrawal period. Similar responses to water deficit regarding the leaf gas exchanges were recorded for the three lines. When subjected to water deficit stress situations, higher F v/F m, ΦPSII and qP were detected for the transgenic lines. Under a SWC of 20% where higher values for such parameters were detected with special relevance for the B5H line, indicating a possible higher ability to withstand severe drought stress and to resist to prolonged periods without water than the B1F and WT lines. |
| Keywords: | Trehalose Photosynthesis Water deficit |
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