title: Secondary metabolite perturbations in Phaseolus vulgaris leaves due to gamma radiation.
abstract: 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.
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa.
authors.forename: T
authors.initials: T
authors.lastname: Ramabulana
authors.affiliation: Department of Physics, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa; NECSA, P.O. Box 582, Pretoria, 0001, South Africa.
authors.forename: R D
authors.initials: RD
authors.lastname: Mavunda
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa; CSIR Biosciences, Natural Products and Agroprocessing Group, Pretoria, 0001, South Africa.
authors.forename: P A
authors.initials: PA
authors.lastname: Steenkamp
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa.
authors.forename: L A
authors.initials: LA
authors.lastname: Piater
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa.
authors.forename: I A
authors.initials: IA
authors.lastname: Dubery
authors.affiliation: Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa. Electronic address: emadala@uj.ac.za.
authors.forename: N E
authors.initials: NE
authors.lastname: Madala
mesh_terms: D002851:Chromatography, High Pressure Liquid; D016002:Discriminant Analysis; D005720:Gamma Rays; D016018:Least-Squares Analysis; D013058:Mass Spectrometry; D055442:Metabolome / Q000528:radiation effects; D027805:Phaseolus / Q000378:metabolism* / Q000528:radiation effects*; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects*; D025341:Principal Component Analysis; D064210:Secondary Metabolism / Q000528:radiation effects*; D036226:Seedlings / Q000378:metabolism / Q000528:radiation effects
keywords: Gamma radiation; Metabolomics; OPLS-DA; Oxidative stress; PCA; Phaseolus vulgaris; UHPLC-qTOF-MS