过量表达脯氨酸的转基因烟草细胞对毒性重金属的抗性增强

Overexpression of △^1- pyrroline - 5 - carboxylate synthetase enhanced tolerance to toxic heavy metals in transgenic tobacco cells

脯氨酸(Proline)在植物对环境胁迫的耐受性中发挥了非常重要的作用。本文中,我们将来自飞蛾豆(V igna acon itifolia L.)的△1-吡咯啉-5-羧酸合成酶(△1-pyrroline-5-carboxylate synthetase,P5CS)基因转化烟草(N icotiana tabacum cv SR I.),经PCR扩增及Southern杂交分析证实飞蛾豆p5 cs基因已整合到烟草细胞基因组中,并在转基因烟草中得以表达。与野生型细胞相比,转基因烟草细胞中脯氨酸含量提高了80%;在毒性重金属镉(Cd,浓度50-100μM)的胁迫下,转基因细胞的生长速度更快,与镉结合的能力也提高近4倍。还原型/氧化型GSH之比和丙二醛水平分析表明,转基因细胞脯氨酸的增加与GSH的氧化还原状态和丙二醛水平是有关的。

Pro has been shown to play an important role in ameliorating environmental stress in plants and microorganisms, including heavy metal stress. Here,A PSCS（ △1 - pyrroline - 5 - carboxylate synthetase） cDNA from mothbean （ Vigna aconitifolia L. ） was introduced into tobacco （ Nicotiana tabacum cv SRI. ） genome. The results of PCR and Southern blot hybridization demonstrated that the foreign p5cs was integrated into the genome of tobacco. We show that transgenic tobacco cells expressing the mothbean pScs gene have 80% higher free - Pro levels than wild - type cells, grow more rapidly in toxic Cd concentrations（ 100 μM）, and bind fourfold more Cd than wild - type cells. Measurements of reduced/oxidized GSH ratios and analyses of levels of malondialdehyde（ MDA）, a product of the free radical damage of lipids, indicate that free Pro levels are correlated with the GSH redox state and MDA levels in heavy metal - treated tobacco.