title: The Pepper Lipoxygenase CaLOX1 Plays a Role in Osmotic, Drought and High Salinity Stress Response.
abstract: In plants, lipoxygenases (LOXs) are involved in various physiological processes, including defense responses to biotic and abiotic stresses. Our previous study had shown that the pepper 9-LOX gene, CaLOX1, plays a crucial role in cell death due to pathogen infection. Here, the function of CaLOX1 in response to osmotic, drought and high salinity stress was examined using CaLOX1-overexpressing (CaLOX1-OX) Arabidopsis plants. Changes in the temporal expression pattern of the CaLOX1 gene were observed when pepper leaves were treated with drought and high salinity, but not when treated with ABA, the primary hormone in response to drought stress. During seed germination and seedling development, CaLOX1-OX plants were more tolerant to ABA, mannitol and high salinity than wild-type plants. In contrast, expression of the ABA-responsive marker genes RAB18 and RD29B was higher in CaLOX1-OX Arabidopsis plants than in wild-type plants. In response to high salinity, CaLOX1-OX plants exhibited enhanced tolerance, compared with the wild type, which was accompanied by decreased accumulation of H2O2 and high levels of RD20, RD29A, RD29B and P5CS gene expression. Similarly, CaLOX1-OX plants were also more tolerant than wild-type plants to severe drought stress. H2O2 production and the relative increase in lipid peroxidation were lower, and the expression of COR15A, DREB2A, RD20, RD29A and RD29B was higher in CaLOX1-OX plants, relative to wild-type plants. Taken together, our results indicate that CaLOX1 plays a crucial role in plant stress responses by modulating the expression of ABA- and stress-responsive marker genes, lipid peroxidation and H2O2 production.
authors: Department of Life Science (BK21 program), Chung-Ang University, Seoul 156-756, Republic of Korea These author contributed equally to this work.
authors: Chae Woo
authors: CW
authors: Lim
authors: Department of Integrative Plant Science, Chung-Ang University, Anseong 456-756, Republic of Korea These author contributed equally to this work.
authors: Sang-Wook
authors: SW
authors: Han
authors: Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea Present address: Department of Agricultural Biotechnology, National Academy of Agricultural Science & Technology, Rural Development Administration, Jeonju 560-500, Republic of Korea.
authors: In Sun
authors: IS
authors: Hwang
authors: Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea Present address: The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
authors: Dae Sung
authors: DS
authors: Kim
authors: Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
authors: Byung Kook
authors: BK
authors: Hwang
authors: Department of Life Science (BK21 program), Chung-Ang University, Seoul 156-756, Republic of Korea sclee1972@cau.ac.kr.
authors: Sung Chul
authors: SC
authors: Lee
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002212:Capsicum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000187:drug effects; D008084:Lipoxygenase / Q000378:metabolism*; D009997:Osmotic Pressure; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D054712:Salinity; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D010940:Plant Proteins; D012965:Sodium Chloride; D000040:Abscisic Acid; D008084:Lipoxygenase
keywords: 9-Lipoxygenase; Abscisic acid; CaLOX1; Drought stress; High salinity; Reactive oxygen species