Improved Salt Tolerance By Transformation Of Plants With PEAMT And CMO Genes

Improving the salt tolerance of plants to make use of the abundant resource of seawater and the big area of land with high salts level has became a great problem to solve when we confronted with the serious lack of freshwater, the high concentrations of salts in soils. These years, considerable progress has been achieved in salt tolerant breeding by genetic engineering, especially the transformations that enable transgenic plants suffer with high salinity stress. It is commonly known that salt tolerance is a trait controlled by multigenes. Single gene transformation is hard to solve the problem which might need to transforme more than one gene to the target plant to improve its tolerance greatly.Osmotic adjustment is the main mechanism of salinity tolerance in many plants, and it has two sorts: One is to uptake or exclude of some ions through various antiporters and proton pumps.The other is the development of high capacity to synthesize and accumulate compatible solutes. We're attempting to improve plants'salt tolerance by transforming genes encoding enzymes in the passway to synthesize betaine.To evaluate the effects of combined salt tolerant mechanisms, PEAMT gene from Salicornia herbacea was introduced into the transgenic tobacco containing CMO by Agrobacterium-mediated transformation. Comparing the content of betaine in 3 types of transgenic tobacco lines and their salt tolerance, to study whether transgenic tobacco have better salt tolerance than wild type tobacco.The results of PCR indicated that PEAMT was integrated into the genome of the target plant. Betaine measurement indicated that the transgenic tobacco lines had higher content than that in the wild type,and dual gene transformted tobacco have has more than single gene line.Physiological responses of the double gene transplant to NaCl treatment, reflected by photosynthetic rate (Pn), relative electronic conductivity (Rc/Rc') and chlorophyll content (Chla+b) were better than those in CMO, and these two lines are all better than non-transformed.Our results indicated that it is feasible to improve plants'salt tolerance by transforming genes encoding enzymes in a certain passway. And also showed that multigene transformation could further improve salt tolerance of plant.