Expression Of The Cold-induced Genes Of Ammopiptanthus Mongolicus In Tobacco And The Cold Tolerance Of The Transgenetic Plants

Chilling or freezing stress affects the growth and development of plants. It is the major limiting factor in agricultural productivity and quality, thus preventing crop plants from realizing their full genetic potential. Ammopiptanthus mongolicus is the only evergreen shrub in northwest of China. It can survive -30℃ or even lower temperature in winter.We obtained two cold-induced genes: the AmLEA gene and the AmPI gene from Ammopiptanthus mongolicus. In order to determine whether expression of AmLEA or AmPI confers improved cold properties to plants, we tried to produce transgenic tobacco plants which expressed the genes. Two plant expression vectors based on pBI121 were constructed with CaMW35S-AmLEA and CaMV35S-AmPI. Tabacco plantlets were transformed by Agrobacterium-medicated transformation. It was demonstrated by PCR and Southern blotting that the cold-induced Ammopiptanthus mongolicus genes were successfully integrated into the genomes of transformed plantlets.In this study, we determined the relative conductivity and the chlorophyll fluorescence parameters of the transgenic tobacco and the control tobacco.The results of single factor analysis indicated that the relative conductivity of the transgenic plants achieved the significant difference level to the control plants at -1℃.The determination of chlorophyll fluorescence parameters also showed that the cold tolerance of the transgenic tobacco was higher than the control. All the experiments results above indicated the LEA and the PI gene which obtained from Ammopiptanthus mongolicus have the function of protect plant organizations and cells under cold stress and enhance the tolerance to cold stress.