Transgenic Tobacco (Nicotiana tabacum cv FCV) Plants Over Expressing A Bacterial cod A Gene Show Reduced Oxidative Damage under High Light Stress

摘要

Transgenic tobacco (Nicotiana tabacum cv FCV) special plants expressing a choline oxidase {cod A) gene from Arthrobacter globiformis were obtained through Agrobacterium tumefaciens mediated transformation. The cod A gene expression was targeted to chloroplast. Stress tolerance was evaluated in transgenic plants by exposing the leaf discs to methyl viologen (MV) induced oxidative stress and measured by TTC reduction test. At 2 jlM of methyl viologen the percent reduction in cell viability was as highas 25.5% in wild type, whereas it was only 11.8% and 6.3% in line 1 and line 2 of transgenic plants respectively. At 5 juM methyl viologen, percent reduction in cell viability for wild type was 30.9% and forcod A transgenics is 13.9 and 11.1% in line 1 and line 2 respectively. The chlorophyll retained in transgenic plants was higher especially in those expressing cod A gene and similar trend was also seen regarding the accumulation of pheophytin levels especially at 5 (J,M MV. In wild type plants, the pheophytin accumulated was high and the least was seen in transgenic plants expressing cod A. Our results indicate that the introduction of cod A gene from Arthrobacter globiformis into tobacco could be a potential strategy for improving the plant tolerance to oxidative stress and by protecting the chloro-plast from reactive oxygen species.