IbSIMT1, a novel salt-induced methyltransferase gene from Ipomoea batatas, is involved in salt tolerance

• Published in: Plant cell, tissue and organ culture Vol. 120; no. 2; pp. 701 - 715
• Main Authors: Liu, Degao, He, Shaozhen, Song, Xuejin, Zhai, Hong, Liu, Ning, Zhang, Dongdong, Ren, Zhitong, Liu, Qingchang
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.02.2015; Springer Netherlands; Springer Nature B.V
• Subjects: Abiotic stress; Abscisic acid; acid treatment; Biomedical and Life Sciences; Carboxylate reductase; gene expression regulation; gene overexpression; Genes; Hydrogen peroxide; Ipomoea batatas; Life Sciences; Malondialdehyde; Methionine; Methyltransferase; multigene family; organ culture; Original Paper; Phosphoribulokinase; Photosynthesis; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant protection; Plant Sciences; Proline; Pyrroline-5-carboxylate reductase; Reactive oxygen species; Reductases; Salinity tolerance; salt stress; Salt tolerance; Scavenging; Superoxide dismutase; sweet potatoes; Transgenic plants; Salt tolerance; Physiological mechanism; adenosyl-methionine-dependent methyltransferase; Sweetpotato
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-014-0638-6

S-adenosyl-methionine (SAM)-dependent methyltransferase (MTase) genes are a multigene family; however, only a few have been characterized at the functional level. In the present study, a novel salt-induced SAM-dependent MTase gene, named IbSIMT1, was isolated from salt-tolerant sweetpotato (Ipomoea batatas (L.) Lam.) line ND98. IbSIMT1 contains a DUF248 domain of unknown function and an MTase domain. Expression of IbSIMT1 was up-regulated in sweetpotato under salt stress and abscisic acid treatment. The IbSIMT1-overexpressing sweetpotato (cv. Shangshu 19) plants exhibited significantly higher salt tolerance compared with the wild-type. Proline content was significantly increased, whereas malonaldehyde content was significantly decreased in the transgenic plants. The activities of superoxide dismutase (SOD) and photosynthesis were significantly enhanced in the transgenic plants. H₂O₂was also found to be significantly less accumulated in the transgenic plants than in the wild-type. Overexpression of IbSIMT1 up-regulated the salt stress responsive genes, including pyrroline-5-carboxylate synthase, pyrroline-5-carboxylate reductase, SOD, psbA and phosphoribulokinase genes under salt stress. These findings suggest that the novel IbSIMT1 gene is involved in sweetpotato salt tolerance and enhances salt tolerance of the transgenic sweetpotato plants by regulating osmotic balance, protecting membrane integrity and photosynthesis and increasing reactive oxygen species scavenging capacity.