| Summary: | 碩士 === 國立成功大學 === 熱帶植物科學研究所 === 100 === Myrcene (7-Methyl-3-methylene-1,6-octadiene) is known as one of volatile allelochemicals, but its molecular mode of action is not well understood. We found that Myrcene inhibited root growth and induced reactive oxygen species (ROS) production both in rice root and tobacco leaves. To gain more insight into these cellular responses and antioxidative responses, we performed isoenzyme analysis of rice root and tobacco leaves during Myrcene stress. We found 3 kinds of antioxidative enzyme , CAT, POD and SOD all can be induced when exposure to Myrcene stress in rice roots, and only POD activity can be detected and induced in tobacco leaves.
Myrcene also triggered changes in transcript levels of genes related to signal transduction, transcription factor, cell growth response and phytohormone.. Gene expression profiling of Myrcene-treated rice roots and tobacco leaves revealed upregulated of Mitogen-activated protein kinase (MAPK3 in rice., WIPK, NTF6 in tobacco ), WRKY71, Lipoxygenase and biosynthesis of jasmonic acid. In addition, Myrcene downregulated cyclinA1, B1-1 and D1, indicated that may induce stress response and reduce cycle cycle ratio when expose on Myrcene. We also found ethylene receptor inhibitor, STS-treated tobacco leaves may reduce ROS production, supposed that Myrcene-induced ROS production should through ethylene pathway. Further characterization of these Myrcene-responsive genes may be helpful for better understanding the mechanisms of allelochemical tolerance in plants.
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