Transformation Of NHX1Gene Into Petunia Hybrida And Analysis Of Salt And Alkali Tolerance In Petunia

Soil salinization is one of the most important factors to constraint agriculturaldevelopment and impact the stability of ecological environment. So, improving thesalt-alkaline tolerance of the plants is the most effective method of the development andutilization of saline land.Petunia hybrida is a kind of important virescence plant and playing an importantrole in maintaining and improving ecological environment. In order to improve thesalt-tolerance of petunia, we introduced TvNHX1gene into petunia, and analysed theexpressions of relative genes and salt-alkaline resistance in the petunia transformationof AtNHX1in this study. The main contens and results are as follow.Constucted the vector pBI121-TvNHX1to obtain plant expression vectorp3300-TvNHX1and pGreenⅡ-TvNHX1. p3300-TvNHX1plasmids were digested torelease the linear marker-free and vector-free TvNHX1expression cassette. Three kindsof recombinant DNA p3300-TvNHX1, pGreenⅡ-TvNHX1and TvNHX1linear cassettewere transfered into petunia via pollen tube pathway.The seeds of transgenic petuniacultured in the1/2MS medium with150Mmol/L NaCl. Cutting down all the roots ofthe putative transformed plants, then cultured on1/2MS medium. PCR shows thatTvNHX1has been transformed into the petunia genome. There were5,11,4transgenicplants comfirmed by PCR.All of49T2putative transformed plants with PPT resisitance were transgenicAtNHX1positive plants by PCR confirmed, which indicated that the AtNHX1gene inpetunia could be inherited to the next generation.Seven AtNHX1transgenic plants were proliferated by plant tissue culture in orderto acquire the plants with same genetic background. The WT and transgenic plants weretreated under NaCl and NaHCO3stress. The result showed that transgenic progenyappeared great differences in salt-alkaline tolerance.The transgenic Petunia in differentphases showed a consistent salt tolerance. Most of transgenic plants were much moreresistant to high concentration of NaCl and NaHCO3than the WT plants. The studysuggested that transgenic Petunia have a better salt-alkaline tolerance than WT. Expression of AtNHX1and SOD gene in transgenic Petunia in different phasesafter200mmol/L NaCl treatment48h was studied by semi-quantitative RT-PCR andSOD activity was measured. It was found that transcript amounts of AtNHX1wereup-regulated in most of transgenic Petunia under salt and alkali stress. Transgenic plantsexpressing AtNHX1showed improved sailt-alkaline tolerance. The expression tendencyof AtNHX1in different phases of transgenic Petunia was samliar. AtNHX1may play arole in affecting expression of SOD gene and increasing SOD activity. In this way, thesalt-tolence of transgenic plants had been improved.