Department of Plant Sciences, University of Hyderabad, Hyderabad, India.
Plant Mol Biol. 2010 Jun;73(3):293-308. doi: 10.1007/s11103-010-9615-6. Epub 2010 Feb 11.
Annexins belong to a multigene family of Ca(2+) dependent, phospholipid and cytoskeleton binding proteins. They have been shown to be upregulated under various stress conditions. We generated transgenic cotton plants expressing mustard annexin (AnnBj1), which showed enhanced tolerance towards different abiotic stress treatments like sodium chloride, mannitol, polyethylene glycol and hydrogen peroxide. The tolerance to these treatments was associated with decreased hydrogen peroxide levels and enhanced total peroxidase activity, enhanced content of osmoprotectants- proline and sucrose in transgenic plants. They showed higher retention of total chlorophyll and reduced TBARS in leaf disc assays with stress treatments, and decreased hydrogen peroxide accumulation in the stomatal guard cells when compared to their wild type counterparts. They also showed significantly enhanced fresh weight, relative water content, dry weight under stress. Treatment with sodium chloride resulted in enhanced expression of genes for Delta-pyrroline-5-carboxylase synthetase in leaves, and sucrose phosphate synthase, sucrose synthase and cellulose synthase A in the leaves and fibers of transgenic plants. The transgenic plants maintained normal seed development, fiber quality and cellulose content under stress.
annexin 属于 Ca(2+) 依赖的多基因家族，能与磷脂和细胞骨架结合。已有研究表明 annexin 在各种胁迫条件下表达上调。我们生成了表达芥菜 annexin（AnnBj1）的转基因棉花植株，这些植株对不同非生物胁迫处理（如氯化钠、甘露醇、聚乙二醇和过氧化氢）表现出增强的耐受性。这些处理的耐受性与过氧化氢水平降低和总过氧化物酶活性增强、渗透保护剂脯氨酸和蔗糖含量增加有关。与野生型相比，转基因植株在叶盘实验中显示出更高的叶绿素总保留量和更少的 TBARS，气孔保卫细胞中的过氧化氢积累减少。与对照相比，在胁迫下，转基因植株的鲜重、相对含水量和干重均显著增加。用氯化钠处理导致叶片中 δ-吡咯啉-5-羧酸合成酶基因的表达增强，以及转基因植株叶片和纤维中蔗糖磷酸合酶、蔗糖合酶和纤维素合酶 A 的表达增强。在胁迫下，转基因植株保持正常的种子发育、纤维质量和纤维素含量。
