Overexpression of S‐adenosyl‐l‐methionine synthetase increased tomato tolerance to alkali stress through polyamine metabolism |
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Authors: | Biao Gong Xiu Li Kyle M VandenLangenberg Dan Wen Shasha Sun Min Wei Yan Li Fengjuan Yang Qinghua Shi Xiufeng Wang |
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Institution: | 1. State Key Laboratory of Crop Biology, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Huanghuai Region, Ministry of Agriculture), College of Horticulture Science and Engineering, Shandong Agricultural University, , China;2. Department of Horticultural Sciences, North Carolina State University, , Raleigh, NC, USA |
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Abstract: | S‐adenosyl‐l ‐methionine (SAM) synthetase is the key enzyme involved in the biosynthesis of SAM, which serves as a common precursor for polyamines (PAs) and ethylene. A SAM synthetase cDNA (SlSAMS1) was introduced into the tomato genome using the Agrobacterium tumefaciens transformation method. Transgenic plants overexpressing SlSAMS1 exhibited a significant increase in tolerance to alkali stress and maintained nutrient balance, higher photosynthetic capacity and lower oxidative stress compared with WT lines. Both in vivo and in vitro experiments indicated that the function of SlSAMS1 mainly depended on the accumulation of Spd and Spm in the transgenic lines. A grafting experiment showed that rootstocks from SlSAMS1‐overexpressing plants provided a stronger root system, increased PAs accumulation, essential elements absorption, and decreased Na+ absorption in the scions under alkali stress. As a result, fruit set and yield were significantly enhanced. To our knowledge, this is the first report to provide evidence that SlSAMS1 positively regulates tomato tolerance to alkali stress and plays a major role in modulating polyamine metabolism, resulting in maintainability of nutrient and ROS balance. |
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Keywords: | tomato S‐adenosyl‐l‐methionine synthetase alkali stress polyamine nutrient balance antioxidant system |
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