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Çѱ¹½Ä¹°ÇÐȸ / v.41, no.1, 1998³â, pp.43-49
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( Generation of Active Oxygen Species (AOS) and Induction of $alpha-Glucanase$ Activity by Fungal Elicitor Xylanase in the Suspension Cultured Cells of Tobacco ) |
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It was ivestigated that active oxygen species (AOS) involved in the plant defense responses induced by fungal elicitor xylanase. When xylanase from the fungus Trichoderma viridae was treated to tobacco suspension cultured cells as an elicitor, $eta$-glucanase activity was increased markedly. Lignin biosynthesis was also increased and peaked at 72 h after the treatment with xylanase. The treatment of H2O2 also dramatically increased $eta$-glucanase activity at 24 h, which wasmuch earlier than that of xylanase did. Using lucigenin- and luminol-dependent chemiluminescence, the effects fo xylanase on oxidative burst were examined. Superoxide anion (O2) production was peaked at 40 h and 52 h after xylanase treatment and hydrogen peroxide (H2O2) release was peaked at 44 h and 56 h, suggesting H2O2 burst was followed by O2 generation. The scavengers of AOS, n-propyl gallate (PG) and mannitol, inhibited xylanase-induced $eta$-glucanase activity by 85% and 50%, respectively. The activity of superoxide dismutase (SOD), which catalyzes the dismutation of O2 to H2O2 began to increase from 24 h and reached to maximum at 48 h after xylanase treatment. Pretreatment of N, N,-diethyldithiocarbamate (DDC), known as a SOD inhibitor, causedthe inhibition of H2O2 generation by 80% and reduced the $eta$-glucanase activity by 60%. Treatment of 2,5-norbonadiene (NBD), a specific ethylene-action inhibitor, did not have any significant effect on xylanase-induced $eta$-glucanase activity. This result suggested that ehtylene did not involve in xylanase-induced response. Our results strongly suggest that the AOS generation is an essential component in plant defense response, in which cell wall degrading enzyme, glucanase, contributes to remove the necrotic tissue induced by pathogens. |
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xylanase;AOS;plant defense response;$alpha-gucanase$;signal transduction; |
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Journal of Plant Biology / v.41, no.1, 1998³â, pp.43-49
Çѱ¹½Ä¹°ÇÐȸ
ISSN : 1226-9239
UCI : G100:I100-KOI(KISTI1.1003/JNL.JAKO199811920119982)
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³í¹® Á¦°ø : KISTI Çѱ¹°úÇбâ¼úÁ¤º¸¿¬±¸¿ø |
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