RT - Journal Article T1 - Increasing of Tolerance to Osmotic Stresses in Tobacco Nicotiana tabacum cv. Xanthi through Overexpression of p5cs Gene JF - JSTNAR YR - 2005 JO - JSTNAR VO - 8 IS - 4 UR - http://jstnar.iut.ac.ir/article-1-299-en.html SP - 31 EP - 40 K1 - p5cs gene K1 - 35S promoter K1 - pBI 121 Vector K1 - gus gene K1 - nptII gene K1 - Agrobacterium AB - Proline as a key osmoregulating solute in plants plays an overriding role in osmotic pressure adjustment of the cell under water stress conditions. In plant, a bifunctional enzyme delta-1-pyrroline-5-carboxylate synthetase (p5cs) promotes and directs proline synthesis during drought stress conditions. The activity of this enzyme is strongly induced to increase proline concentration within the cell to prevent the impact of water deficit. In this study, the sequence coded for p5cs enzyme under the control of the cauliflower mosaic virus 35S promoter was cloned into a plasmid containing gus and nptII genes. The construct pBI121-p5cs was then transferred into Agrobacterium tumefaciens C58 (pGV3101) and used for producing transgenic tobacco(Nicotiana tabacum cv. Xanthi) plants. The amplification of a 765 bp band within p5cs gene from transferred plants and forming deep blue color in leaf tissues of the explants indicated the successful introduction of p5cs construct into nuclear genome of tobacco plants through Agrobacterium-mediated transformation. The two-month old plants growing under normal condition besides the five-day seedlings under drought stress were subjected to determination of proline concentration. Comparison of P5cs product levels between control and water tolerated plants indicated an increase of proline of about 96.91 to 1330.891 mg/g and of 204.454 to 2039.77 mg/g in plants under normal irrigation and under drought stress, conditions respectively. The significant difference between the levels of proline product in control and transgenic plants under different growing conditions demonstrated the expression of targeted gene (p5cs) in engineered tobacco plants that may pave the way to overcome the water stress problem in agronomically useful crops. LA eng UL http://jstnar.iut.ac.ir/article-1-299-en.html M3 ER -