Identify And Physiological Indices Analysis On The Mutants Of Transgenic Cotton

Plant transgenic technique is an efficient approach to improve plant characters directionally and to induce mutations in high frequency. It is significant for crop varieties' improving and breeding. The progenies of different transgenic land cotton lines, which were introduced transposon activation construct to cotton genome via Agrobacterium tumefeciens transformation, were used as materials in this research. The preliminary identification of the main strains of transgenic land cotton by molecular biology and the effects of the construct on mutation induced, and a preliminary analysis of physiological and biochemical differences of related transgenic mutants were studied. The main results are as follows:1. Based on the specific primers of screening marker of NPTâ…¡gene, the positive rate of PCR amplified in the transgenic 4105 lines was 26.1%, and 27.2% in that of transgenic 1107 lines. So the transformation efficiency was almost the same in the two receptors;. Based on the specific primers of Bar gene, which linked with Ds element, the positive rates of PCR amplified in the progenies of transgenic 4105 and 1107 were 28.1% and 31.8% respectively. So we could calculate the ratio of transgenic plants only harbored Bar gene was 17.4%, the total number was 122. It indicated that Ds element has been dissociated from its original location, and inserted into the other chromosome, and separated with Ac in the progenies. It is easy to obtain the stabilized mutants from the events.2. The results of Southern Blotting in T3 plants basically proved that the foreign T-DNA had been integrated into the cotton genome.3. The results of physiological and biochemical indices of some transgenic lines indicated that the content of chlorophyll and photosynthesis rate of L3 line from transgenic 4105 were significantly higher than that of the control; the differences of chlorophyll content and photosynthesis rate between L9 which from transgenic 1107 and its control were found to be achieved a significant differences during the bud stage, and a most significant differences during the flowering and the boll opening stage. These physiological differences reflected that CaMV35S enhancer of the transposon activation construct might affect over-expression of some genes nearby the Ds inserted site. In addition, the chlorophyll content and photosynthesis rate of transgenic 4105 were higher than that of transgenic 1107, which suggested that the mutation effects varied with transgene receptors. Totally, we found more late-maturing mutations in the transgenic 4105 progenies and more early-maturing mutations in the transgenic 1107 lines. 4. The analysis of leaf soluble protein subunits with SDS-PAGE showed the overexpression of some proteins in the transgenic plants, especially a subunit of approximately 50kD molecular weight. Furthermore, a new 42kD subunit appeared in the transgenic cotton progenies, but not in the related control, which indicated that the over-expression of some genes induced by the enhancer in the transgenic lines caused related proteins synthesis, but the function of the protein related with the subunits is still to proved by the further experiment.5. The results of the POD isozymes in the different transgenic cotton lines by PAGE showed the different pattern of the POD isozymes compared with that of the control. It also suggested that some genes might be activated by the enhancer followed the insertion of Ds nearby, and therefore influenced the related metabolism in the transgenic cotton plants.