Effect of drought stress on transgenic tobacco (Nicotinia tabacum L. cv. Wisconsin) plants containing P5CS gene under in vitro culture

In this study¡ to evaluate the effects of drought stress on transgenic tobacco (Nicotinia tabacum L. cv. Wisconsin) containing P5CS gene and non transgenic plants under in vitro culture, these plants were grown on MS media containing 0¡ 5¡ 10¡ 20 and 30% PEG for 28 days. To select the drought tolerant and sensitive plants and also the mechanisms of drought tolerance in transgenic tobacco plants parameters such as wet and dry weight and photosynthetic pigments content (chlorophyll a¡ b¡ total chlorophyll and carotenoid), soluble sugars and total soluble protein content were measured 28 days after PEG treatment. Results indicated that reduction of wet and dry weights and photosynthetic pigments content in transgenic plants were lower than the non transgenic plants. Soluble carbohydrates in both plants in 10 and 20% concentrations, significantly increased. Total soluble protein content were decreased in non transgenic plants in 30% PEG, and remained unchanged in transgenic plants. SDS-PAGE results in leaves showed different protein patterns between transgenic and non transgenic plants and also between treated and non treated plants for example, protein bands about 35 and 45 KD, Proline as a key osmoregulating solute in plants play an overriding role in osmotic pressure adjustment of the cell under water stress condition. Thus transgenic plants containing P5CS gene might be resistant against drought stress.