• 제목/요약/키워드: Xanthomonas oryzae pv

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Preservation Methods of Xanthomonas campestris pv. oryzae in Relation to Virulence and Colony-Type Variation (벼 흰빛잎마름병균의 균주보관에 따른 병원성 및 집락변이현상)

  • Hwang In Gyu;Cho Yong Sup
    • Korean Journal Plant Pathology
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    • v.2 no.3
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    • pp.150-157
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    • 1986

  • Effects of presservation methods on viability and virulence of Xanthosmonas compestris pv. oryzae were investigated. The incidence of colony-type variants from freeze-dried and deep-frozen cultures was also determined. The suspending medium for freeze-dried cultures containing $10\%$ sucrose and $1\%$ gelatin showed the highest viability, and the virulence was well maintained in the suspending medium containing $2\%$ dextrin, $0.5\%$ ascorbic acid, 0.5% ammonium chloride, $0.5\%$ thiourea, and $0.85\%$ NaCl. Serially transferred cultures became attenuated. Rough colonies which had wrinkled surface occurred at a frequency of $1.9\%$ to $15.8\%$ during freeze-drying and freezing. The rough colonies consisted of nonseptated filamentous cells and rod-shaped cells. The virulence of rough colonies was weak as compared with the normal colony type.

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Effect of GlycinecinA on the Control of Bacterial Leaf Spot of Red Pepper and Bacterial Leaf Blight of Rice

  • Jeon, Yong-Ho;Moonjae Cho;Cho, Yong-Sup;Ingyu Hwang
    • The Plant Pathology Journal
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    • v.17 no.5
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    • pp.249-256
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    • 2001

  • Xanthomonas axonopodis pv. glycines 8ra produces a bacteriocin called glycinecinA, which specifically inhibits the growth of bacteria belonging to Xanthomonas species. GlycinecinA was produced by culturing Escherichia coli DH5 containing biosynthetic genes for glycinecinA, and was tested for its control effect against X. vesicatoria on red pepper and X. oryzae pv. oryzae on rice. The bacteriocin activity was much higher in the cell extract than in the supernatant. It reached a maximum level at the stationary phase, ws maintained up to 2 months at room temperature and approximately 10 months at $4^{\circ}$. The optimum concentration of glycinecinA for the control in the greenhouse and in the field was 12,800 AU/ml. In this study, the activity of glycinecinA on rice and red pepper leaves continued for 7-8 days, during which the pathogen populations remained at low levels. Bacterial leaf spot of red pepper and bacterial leaf blight of rice were significantly reduced by the bacteriocin treatments. The control efficacy was as high as, or even higher than, the chemical treatment of copper hydroxide. These results suggest that the bacteriocin is a potential control agent for bacterial diseases.

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