Photosynthesis and Plant Stress Biology Laboratory, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
Planta. 2012 Oct;236(4):1339-49. doi: 10.1007/s00425-012-1716-9. Epub 2012 Jul 27.
Generation of reactive oxygen species (ROS) in plants is an inevitable consequence of adverse environmental cues and the ability to detoxify deleterious by-products of ROS-mediated oxidation reactions reflect an important defence strategy to combat abiotic stress. Here, we have cloned the eutypine reducing aldehyde reductase gene (VrALR) from Vigna radiata (L.) Wilczek roots. We have expressed and purified the VrALR protein and analyzed its enzyme kinetic parameters and catalytic efficiency with three different substrates to confirm its identity. The functional characterization of this enzyme was unravelled through heterologous expression of the gene in Escherichia coli BL21 and an oxidative stress-sensitive Saccharomyces cerevisiae mutant strain, W3O3-1-A. Finally, the endogenous VrALR enzyme activity and the mRNA expression patterns of the VrALR gene in the roots of V. radiata in response to progressive drought stress in vivo was studied to correlate the ROS-detoxifying role of this important enzyme under the influence of progressive drought stress. Our results, for the first time, demonstrate that eutypine reducing VrALR provides varying degree of stress tolerance in bacteria, yeast systems and also plays a promising protective role against oxidative stress in V. radiata roots during gradual water deprivation. The present study provides an unequivocal evidence to understand the crucial role of aldehyde reductase ROS-detoxifying system which is highly essential for developing stress tolerance in economically important crop plants.
植物中活性氧（ROS）的产生是环境胁迫的必然结果，而能够清除 ROS 介导的氧化反应中有害副产物的能力则反映了一种重要的防御策略，有助于抵御非生物胁迫。在这里，我们从豇豆（Vigna radiata (L.) Wilczek）根中克隆了赤藓糖醇还原醛还原酶基因（VrALR）。我们表达并纯化了 VrALR 蛋白，并分析了其与三种不同底物的酶动力学参数和催化效率，以确认其身份。通过将该基因在大肠杆菌 BL21 和氧化应激敏感的酿酒酵母突变体 W3O3-1-A 中的异源表达，揭示了该酶的功能特征。最后，我们研究了 V. radiata 根中内源性 VrALR 酶活性和 VrALR 基因的 mRNA 表达模式，以探讨在渐进性干旱胁迫下，这种重要酶在 ROS 解毒中的作用。我们的研究结果首次表明，赤藓糖醇还原 VrALR 在细菌、酵母系统中提供了不同程度的胁迫耐受性，并且在 V. radiata 根在逐渐缺水过程中对氧化应激也发挥了有前途的保护作用。本研究为理解醛还原酶 ROS 解毒系统的关键作用提供了明确的证据，该系统对于在经济上重要的作物植物中发展胁迫耐受性至关重要。
