title: Overexpression of S-adenosyl-L-methionine synthetase increased tomato tolerance to alkali stress through polyamine metabolism.
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.
authors.affiliation: 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, Taian, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Gong
authors.forename: Xiu
authors.initials: X
authors.lastname: Li
authors.forename: Kyle M
authors.initials: KM
authors.lastname: VandenLangenberg
authors.forename: Dan
authors.initials: D
authors.lastname: Wen
authors.forename: Shasha
authors.initials: S
authors.lastname: Sun
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Yang
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Shi
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects* / Q000235:genetics; D000468:Alkalies / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D005030:Ethylenes / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects / Q000235:genetics; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D008716:Methionine Adenosyltransferase / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010641:Phenotype; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D018520:Plant Shoots / Q000187:drug effects / Q000502:physiology; D030821:Plants, Genetically Modified; D011073:Polyamines / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects; D012964:Sodium / Q000378:metabolism; D017693:Sodium Bicarbonate / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects* / Q000235:genetics; D013481:Superoxides / Q000378:metabolism
chemical_list: D000468:Alkalies; D000975:Antioxidants; D005030:Ethylenes; D011073:Polyamines; D012333:RNA, Messenger; D013481:Superoxides; D017693:Sodium Bicarbonate; C036216:ethylene; D012964:Sodium; D008716:Methionine Adenosyltransferase; D011188:Potassium
keywords: S-adenosyl-l-methionine synthetase; alkali stress; antioxidant system; nutrient balance; polyamine; tomato