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Overexpression of MfSAMS1 Improves Chilling Tolerance in Transgenic Stylo
Author(s) -
Qiu Hong,
Zhou Min,
Huang Lei,
Guo Zhenfei,
Lu Shaoyun
Publication year - 2019
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2019.03.0192
Subject(s) - polyamine oxidase , catalase , polyamine , transgene , superoxide dismutase , biology , spermidine , genetically modified crops , drought tolerance , botany , antioxidant , horticulture , biochemistry , enzyme , gene
Stylo [ Stylosanthes guianensis (Aublet) Sw.] is an important forage legume and cover crop in tropical and southern subtropical regions. Its growth and survival are largely affected by low temperature in winter in subtropical regions. It is important to improve its chilling tolerance. S ‐adenosylmethionine synthetase (SAMS) is the key enzyme catalyzing the formation of S ‐adenosylmethionine (SAM), a precursor of polyamines synthesis. To improve chilling tolerance in stylo, MfSAMS1 from Medicago falcata was overexpressed in stylo plants. DNA gel blot hybridization and quantitative reverse transcription PCR analysis showed that MfSAMS1 was inserted into the genomes of transgenic plants and expressed. Compared to the wild‐type, transgenic plants had enhanced SAM and spermidine levels and increased chilling tolerance with higher level of the maximum photochemical efficiency of photosystem II ( F v / F m ) and lower ion leakage after chilling treatment. Polyamine oxidase activity and H 2 O 2 levels were increased in transgenic plants compared with the wild‐type. In addition, higher activities of superoxide dismutase and catalase were observed in transgenic plants than in the wild‐type. The results suggest that overexpression of MfSAMS1 promoted polyamine synthesis and oxidation, which in turn improved H 2 O 2 –induced antioxidant protection and protected transgenic plants against chilling stress. Core Ideas Transgenic stylo plants overexpressing MfSAMS1 were produced. Plants showed promoted polyamine synthesis and oxidation. Transgenic plants had increased chilling tolerance with higher antioxidant levels.