Molecular Mechanistic Of SeNHX1for Tolerance To Salt And Primary Study On Salt-Tolerance Of Lisianthus

Salinity stress is one of the most serious factors limiting the growth of plants.Many research topics focus on breeding salt-resistant varieties by geneticengineering. In this study, In order to breed salt-resistant variety of EustomaGradiflorum, we firstly analyzed the function, localization and salt–tolerancemechanism of SeNHX1in yeast and tobacco, and then transformed it into targetplants.Yeast expression vector pYES2-SeNHX1，pYES2-GFP, pYES2-SeNHX1-GFP,and binary plant expression vector PBin438-SeNHX1were constructed, and then wasintroduced into S. cerevisiae and plants respectively. SeNHX1was localized on thevacuolar membrane of yeast by fluorescence assay. The function of Na~+-detoxicationin the nhx1mutant strain296H and higher salt tolerance in the strain W303, whichall contained the vectors of pYES2-SeNHX1or pYES2-SeNHX1-GFP, were gained.Overexpression of SeNHX1in tobacco increased salt tolerance in both “in vitro”and pot culture. when the Na~+content in pot soil was more than9.7mg/g, comparedto wild-type, transgenic plants accumulated2.3mg/g FW greater amount of Na~+inold leaves and0.36mg/g FW higher proline in young leaves, but themalondialdehyde (MDA) content was significantly lower, The research findingsdisplay a strategy to improve tolerance to salt in SeNHX1-transgenic tobacco by (1)absorbing more Na~+for growth in saline soil,(2) accumulating Na~+in old leaves toprevent young tissue from Na~+-toxicity,(3) then, pumping Na~+into vacuole bySeNHX1for detoxification.In addition, Eustoma Gradiflorum was transformed by C58withpBin438-SeNHX1, and salt tolerance transgenic plants of Eustoma Gradiflorum havegrown normally for two months in greenhouse.