Tuteja Narendra, Banu Mst Sufara Akhter, Huda Kazi Md Kamrul, Gill Sarvajeet Singh, Jain Parul, Pham Xuan Hoi, Tuteja Renu
International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
Stress Physiology and Molecular Biology Lab, Centre for Biotechnology, MD University, Rohtak, India.
PLoS One. 2014 May 30;9(5):e98287. doi: 10.1371/journal.pone.0098287. eCollection 2014.
The DEAD-box helicases are required mostly in all aspects of RNA and DNA metabolism and they play a significant role in various abiotic stresses, including salinity. The p68 is an important member of the DEAD-box proteins family and, in animal system, it is involved in RNA metabolism including pre-RNA processing and splicing. In plant system, it has not been well characterized. Here we report the cloning and characterization of p68 from pea (Pisum sativum) and its novel function in salinity stress tolerance in plant.
The pea p68 protein self-interacts and is localized in the cytosol as well as the surrounding of cell nucleus. The transcript of pea p68 is upregulated in response to high salinity stress in pea. Overexpression of p68 driven by constitutive cauliflower mosaic virus-35S promoter in tobacco transgenic plants confers enhanced tolerances to salinity stress by improving the growth, photosynthesis and antioxidant machinery. Under stress treatment, pea p68 overexpressing tobacco accumulated higher K+ and lower Na+ level than the wild-type plants. Reactive oxygen species (ROS) accumulation was remarkably regulated by the overexpression of pea p68 under salinity stress conditions, as shown from TBARS content, electrolyte leakage, hydrogen peroxide accumulation and 8-OHdG content and antioxidant enzyme activities.
To the best of our knowledge this is the first direct report, which provides the novel function of pea p68 helicase in salinity stress tolerance. The results suggest that p68 can also be exploited for engineering abiotic stress tolerance in crop plants of economic importance.
DEAD盒解旋酶在RNA和DNA代谢的各个方面大多是必需的，并且它们在包括盐度在内的各种非生物胁迫中发挥重要作用。p68是DEAD盒蛋白家族的重要成员，在动物系统中，它参与RNA代谢，包括前体RNA加工和剪接。在植物系统中，其特征尚未明确。在此，我们报道了豌豆（Pisum sativum）中p68的克隆与特征分析及其在植物耐盐胁迫中的新功能。
豌豆p68蛋白可自我相互作用，定位于细胞质以及细胞核周围。豌豆p68的转录本在豌豆受到高盐胁迫时上调。由组成型花椰菜花叶病毒35S启动子驱动的p68在烟草转基因植物中的过表达通过改善生长、光合作用和抗氧化机制赋予了对盐胁迫更强的耐受性。在胁迫处理下，过表达豌豆p68的烟草积累的钾离子水平高于野生型植物，钠离子水平低于野生型植物。从丙二醛含量、电解质渗漏、过氧化氢积累、8-羟基脱氧鸟苷含量和抗氧化酶活性可以看出，在盐胁迫条件下，豌豆p68的过表达显著调节了活性氧（ROS）的积累。
据我们所知，这是第一份直接报道，提供了豌豆p68解旋酶在耐盐胁迫方面的新功能。结果表明，p68也可用于培育具有经济重要性的作物对非生物胁迫的耐受性。
