A novel Tartary buckwheat gene FtIST1, associated with salt tolerance, was isolated and identified via over-expression and VIGS

Abstract

FtIST1 is a novel SBP gene isolated from salt-responsive Tartary buckwheat, and its molecular characteristics and function in salt tolerance are unclear. With the use of DNAMAN and MEGA7.0 software and online analysis program SOPMA, we performed the bioinformatics analysis of the novel FtIST1 gene. We also identified the function of FtIST1 gene via over-expression and VIGS (virus-induced gene silencing). FtIST1 gene was cloned from Tartary buckwheat, and its GenBank accession number is MK799640. FtIST1 belongs to the SBP transcription factor gene family, it is 374 bp long and encodes 99 amino acids. The molecular weight and isoelectric point of FtIST1 protein are 11.7 kDa and 8.78, which is predicted to be a soluble hydrophilic protein. Through analyzing the physiological characteristics of transgenic Arabidopsis, it was found that the activities of antioxidant enzymes (SOD, POD and CAT), chlorophyll content, Fv/Fm, Fv/F0, net photosynthetic rate, fresh weight and dry weight, K+ and Mg2+ content increased significantly in Arabidopsis with over-expression of FtIST1 gene, while the plasmalemma permeability, chlorophyll a fluorescence F0 and Na+ content of leaves decreased significantly, indicating that the over-expression of FtIST1 gene can obviously improve the physiological characteristics of Arabidopsis under salt stress and the salt tolerance of transgenic Arabidopsis. After successfully inhibiting the expression of FtIST1 gene in Tartary buckwheat by VIGS technology, the activities of antioxidant enzymes such as SOD, POD and CAT in Tartary buckwheat decreased significantly, while the plasmalemma permeability and Na+ content of leaves increased significantly, indicating that the loss of FtIST1 gene expression in Tartary buckwheat led to the decrease of antioxidant capacity, the increase of cell membrane damage, the increase of Na+ content in shoot and the obvious decrease of salt tolerance. Our data indicate that FtIST1 is a salt tolerance gene, which is closely associated with salt tolerance of Tartary buckwheat.