Tag Archives: jasmonic acid
Lipoxygenases and their metabolites in formation of plant stress tolerance
L. M. Babenko1, M. M. Shcherbatiuk1, T. D. Skaterna2, I. V. Kosakivska1
1M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: lilia.babenko@gmail.com
The review focuses on the analysis of new information concerning molecular enzymology of lipoxygenases – proteins involved in lipid peroxidation and found in animals and plants. Modern concept of structural features, catalytic characteristics and functions of lipoxygenase family enzymes as well as products of their catalytic activity in plants have been discussed and summarized. Issues of enzyme localization in plant cells and tissues, evolution and distribution of lipoxygenases, involvement in production of signaling substances involved in formation of adaptation response to abiotic and biotic stress factors and in regulation of lipoxygenase signal system activity are highlighted. Participants of the elements signaling of LOX-pathway reception and transduction into genome are considered. Special attention is given to jasmonates, metabolites of the allene oxide synthase branch of the lipoxygenase cascade, because these metabolites have high biological activity, are ubiquitously present in all plant organisms, and are involved in regulation of vitally important processes. Data concerning lipoxygenase phylogeny, possible occurrence of a common predecessor for modern isoforms of the enzyme in pro- and eukaryote have been examined. Some results of our studies that open up possibilities of using the lipoxygenase catalytic activity characteristics as biological markers in plant stress tolerance researches are given.
Reactive oxygen forms and Ca ions as possible intermediaries under the induction of heat resistance of plant cells by jasmonic acid
Yu. V. Karpets, Yu. E. Kolupaev, T. O. Yastreb, O. I. Oboznyi,
M. V. Shvydenko, G. A. Lugova, A. O. Vayner
Dokuchayev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@mail.ru
The participation of reactive oxygen species (ROS) and calcium ions in realization of influence of exogenous jasmonic acid (JA) on the heat resistance of wheat coleoptiles has been investigated. Influence of 1 µM JA caused the transitional intensifying of generation of superoxide anion-radical (O2•–) and hydrogen peroxide in coleoptiles with the maximum within 15-30 minutes after the treatment beginning. Within the first hour after the beginning of coleoptiles treatment with JA the increase of superoxide dismutase (SOD) activity was noted. Later on (within 5-24 hours after the treatment beginning) there was the lowering of ROS generation by coleoptiles of experimental variant, and the SOD activity approached the control value. Intensifying of generation of superoxide radical induced by JA was suppressed by the antioxidant ionol and was partially levelled by imidazole (inhibitor of NADPH-oxidase), EGTA (chelator of extracellular calcium) and lanthanum chloride (calcium channels blocker). Pretreatment of coleoptiles with the ionol, imidazole, EGTA and LaCl3 also partially removed the effect of increase of their resistance to the damaging heating caused by exogenous JA. It is supposed that the ROS generated with participation NADPH-oxidase, which activity depends on the receipt of calcium ions from extracellular space in the cytosol, are involved in realization of physiological effects of JA.
Lipoxygenases and plant cell metabolism regulation
I. V. Pokotylo, Y. S. Kolesnikov, M. V. Derevyanchuk, A. I. Kharitonenko, V. S. Kravets
Institute of Bioorganic Chemistry and Petrochemistry,
National Academy of Sciences of Ukraine, Kyiv;
e-mail: kravets@bpci.kiev.ua
Lipoxygenases are widespread plant enzymes that catalyze the peroxidation of polyunsaturated fatty acids. This reaction is pivotal in the enzymatic cascade that leads to production of numerous metabolism regulators named oxylipins. The activity of these biologically active substances is directly associated with defence reactions in conditions of biotic and abiotic stresses as well as with the regulation of plant growth, propagation and senescence. In this review the contemporary notions about lipoxygenases classification, structure and catalytic properties are summarized. The features of enzyme activity regulation by transcriptional and posttranslational mechanisms in addition to the role of lipoxygenase catalysis in plant cell signalling are discussed.