Ramabulana T, Mavunda R D, Steenkamp P A, Piater L A, Dubery I A, Madala N E
Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa.
Department of Physics, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa; NECSA, P.O. Box 582, Pretoria, 0001, South Africa.
Plant Physiol Biochem. 2015 Dec;97:287-95. doi: 10.1016/j.plaphy.2015.10.018. Epub 2015 Oct 20.
Oxidative stress is a condition in which the balance between the production and elimination of reactive oxygen species (ROS) is disturbed. However, plants have developed a very sophisticated mechanism to mitigate the effect of ROS by constantly adjusting the concentration thereof to acceptable levels. Electromagnetic radiation is one of the factors which results in oxidative stress. In the current study, ionizing gamma radiation generated from a Cobalt-60 source was used to induce oxidative stress in Phaseolus vulgaris seedlings. Plants were irradiated with several radiation doses, with 2 kGy found to be the optimal, non-lethal dose. Metabolite distribution patterns from irradiated and non-irradiated plants were analyzed using UHPLC-qTOF-MS and multivariate data models such as principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA). Metabolites such as hydroxycinnamic phenolic acids, flavonoids, terpenes, and a novel chalcone were found to be perturbed in P. vulgaris seedlings treated with the aforementioned conditions. The results suggest that there is a compensatory link between constitutive protectants and inducible responses to injury as well as defense against oxidative stress induced by ionizing radiation. The current study is also the first to illustrate the power of a metabolomics approach to decipher the effect of gamma radiation on crop plants.
氧化应激是一种活性氧（ROS）产生与清除之间的平衡受到干扰的状态。然而，植物已经进化出一种非常复杂的机制，通过不断将ROS浓度调节至可接受水平来减轻ROS的影响。电磁辐射是导致氧化应激的因素之一。在本研究中，使用钴 - 60源产生的电离γ辐射在菜豆幼苗中诱导氧化应激。用几种辐射剂量照射植物，发现2 kGy是最佳的非致死剂量。使用超高效液相色谱 - 四极杆飞行时间质谱（UHPLC-qTOF-MS）以及主成分分析（PCA）和正交投影到潜在结构判别分析（OPLS-DA）等多变量数据模型分析受辐照和未受辐照植物的代谢物分布模式。发现诸如羟基肉桂酸酚酸、黄酮类化合物、萜类化合物和一种新型查耳酮等代谢物在上述条件处理的菜豆幼苗中受到干扰。结果表明，组成型保护剂与对损伤的诱导反应以及对电离辐射诱导的氧化应激的防御之间存在补偿联系。本研究也是首次说明代谢组学方法在解读γ辐射对农作物影响方面的作用。
