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

Abstract

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. H 2 O 2 was 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.

Transcript profile analysis reveals important roles of jasmonic acid signalling pathway in the response of sweet potato to salt stress

“…Plant roots alter their developmental process to rapidly adapt to salt stress. The salt tolerance of sweet potato is improved through increasing betaine, proline and ABA contents, activating ROS scavenging and enhancing myo-inositol biosynthesis, photosynthesis and ion homoestasis29303132454647484950.…”

“…For the RNA-Seq analysis, the plants were grown in MS medium at 27 ± 1 °C for 13 h/day under cool-white fluorescent light at 54 μM/m 2 /s for 4 weeks and were subsequently cultivated in Hoagland solution with 200 mM NaCl for 0, 12 and 48 h according to our previous studies30313250. The roots were excised, immediately frozen in liquid nitrogen and subsequently stored at −80 °C until further use.…”

“…is an important root and tuber crop and is used as an industrial and bio-energy resource. This crop has considerable potential to grow on saline land2627, and several salt tolerance genes have been identified in sweet potato2829303132. Recently, de novo whole-genome sequencing of the selfed line Mx23Hm and the highly heterozygous line 0431-1 of I. trifida (2n = 2x = 30, one of the likely diploid ancestors of sweet potato) was performed on an Illumina HiSeq platform, but the assembly and annotation of these genomes are still in the early stages33.…”

A myo‐inositol‐1‐phosphate synthase gene, IbMIPS1, enhances salt and drought tolerance and stem nematode resistance in transgenic sweet potato

“…The BADH gene from spinach improved tolerance to salt, MV‐mediated oxidative and low temperature stresses in transgenic sweet potato (Fan et al ., ). Overexpression of the genes, IbOr , IbLCY‐ ε, IbNFU1 , IbP5CR , IbMas and IbSIMT1 , from sweet potato enhanced salt tolerance of this crop (Kim et al ., ,b; Liu et al ., ,b,c, ; Wang et al ., ).…”

High-throughput deep sequencing reveals the important role that microRNAs play in the salt response in sweet potato (Ipomoea batatas L.)

“…As a source of bioenergy, sweet potato is mainly planted on marginal land; hence, improving its salt tolerance is important to maintain productivity [26,27]. Until now, a series of salttolerance-associated genes, such as IbOr, IbNFU1, IbP5CR, IbMas, IbSIMT1, IbMIPS1 and IbZFP1, has already been well characterised in sweet potatoes [26,[28][29][30][31][32][33][34][35]. However, very little work has been done on sweet potato miRNAs, and miRNA-related salt stress in sweet potato has not been investigated.…”