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Rhizoctonia Blight of Azolla japonica Caused by Rhizoctonia solani

Rhizoctonia solani에 의한 큰물개구리밥(Azolla japonica) 마름병

  • Lee, Jung-Han (Department of Chemistry and Research Institute of Life Science, Gyeongsang National University) ;
  • Cha, Jea-Yul (Department of Applied Biology, College of Agriculture and Life Science, Gyeongsang National University) ;
  • Noh, Gil-Han (Department of Applied Biology, College of Agriculture and Life Science, Gyeongsang National University) ;
  • Han, Ki-Soo (Department of Applied Biology, College of Agriculture and Life Science, Gyeongsang National University) ;
  • Bae, Dong-Won (Central Instrument Facility, Gyeongsang National University) ;
  • Kwon, Young-Sang (Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University) ;
  • Lim, Chae-Shin (Gyeongsangnam-do Agricultural Research and Extension Service) ;
  • Jeong, Sung-Woo (Department of Horticulture, Gyeongsang National University) ;
  • Kwon, Jin-Hyeuk (Gyeongsangnam-do Agricultural Research and Extension Service) ;
  • Park, Chung-Gyoo (Department of Applied Biology, College of Agriculture and Life Science, Gyeongsang National University) ;
  • Kwak, Youn-Sig (Department of Applied Biology, College of Agriculture and Life Science, Gyeongsang National University)
  • Received : 2011.07.15
  • Accepted : 2011.10.02
  • Published : 2011.12.31

Abstract

Azolla Lam. is a small aquatic fern with deeply bilobed leaves, which are consisted of a thick greenish, with chlorophyll, upper (dorsal) lobe and a thinner, translucent lower (ventral) lobe, without chlorophyll, submerged in the water. Azolla blight was observed at a lotus pond. Mycological characteristics of the fungus associated with Azolla blight was immediately determined as Rhizoctonia sp. by the thickness and branching of hypha at right angles at the point toward the distal end of septa, with branching hypha is constricted. The fungus produced brown mycelia and dark brown sclerotia on PDA. The optimum temperature for mycelial growth and sclerotia formation were $25^{\circ}C$ and $30^{\circ}C$, respectively. The optimum temperature for fungal infection was $30^{\circ}C$, when spray inoculated. Phylogenetic analysis of rDNA-ITS revealed that the fungus was identified as Rhizoctonia solani (AG-1 IA) closest to one causing rice sheath blight disease. This is the first report on the blight disease of Azolla caused by R. solani in Korea.

연 재배연못에서 발견된 큰물개구리밥에 R. solani AHL1에 의해 국지적으로 말라 고사하는 것을 관찰하였다. 병원균을 분리하여 형태적 특징을 조사한 결과 균사는 두께가 $5-6{\mu}m$이고 둔각분지를 하고 있었으며 핵형은 다핵형이었다. 배양적 특성으로 균사생육은 $25^{\circ}C$에서 가장 왕성하였으며 $30^{\circ}C$에서 가장 많은 균핵이 형성되었다. 온도에 따른 병원성과 발병정도를 조사한 결과 $20^{\circ}C$, $25^{\circ}C$$30^{\circ}C$에서 모두 병원성이 나타났으며 발병정도는 $30^{\circ}C$에서 가장 높게 나타났다. 병원균을 유전자 수준에서 동정하기 위해 ITS 영역을 Neighbor-Joining 방법을 이용하여 계통분류분석을 수행한 결과 R. solani로 동정되었다. 본 연구에서 분리된 R. solani AHL1은 벼잎집무늬마름병을 유발하는 병원균과 유사하여 벼에 대한 병 발생 여부는 추가적으로 연구가 필요하다. 현재 농업은 화학비료의 사용을 억제하는 추세로 녹비를 이용한 유기농업으로, 주요 녹비인 Azolla 안정적인 사용을 위하여 Azolla에 발생하는 병에 대한 연구가 더 이루어져야 된다고 사료된다.

Keywords

References

  1. Becking, J. H. 1979. Environmental requirements of Azolla for use in tropical rice production. In: Nitrogen and Rice, pp. 345-374. International Rice Research Institute, Los Banos, Laguna, Philippines.
  2. Cagauan, A. G. and Pullin, R. S. V. 1991. Azolla in aquaculture: Past, present and future. In: Recent Advances in Aquaculture, ed. by J. Muir and R. J. Roberts, pp. 104-130. Blackwell Science, Oxford, UK.
  3. Kannaiyan, S. 1987. Azolla Utilization: Proceedings of the workshop on Azolla Use, Fuzhou, Fujian, China, 31 March-5 April 1985. International Rice Research Institute, Philippines. pp. 107-118.
  4. Lee, C. H., He, S. B., Lee, Y. C., Oh, D. M. and Kim, S. H. (eds) 2004. Manuals for organic and eco-friendly farming. National Academy of Agricultural Science. Suwon, Korea. (In Korean)
  5. Lee, T. B. 1979. Illustrated flora of Korea. Hyang Mun Sa, Seoul, Korea. (In Korean)
  6. Liu, C. C. and Zheng, W. W. 1989. Azolla in China. Agriculture Publishing House, Beijing, (In Chinese)
  7. Lumpkin, T. A. and Plucknett, D. L. 1982. Azolla as a green manure: Use and management in crop production. Westview Press, Bolder, CO. 162 pp.
  8. McConnachie, A. J., de Wit, M. P., Hill, M. P. and Byrne, M. J. 2003. Economic evaluation of the successful biological control of Azolla filiculoides in South Africa. Biol. Control 28: 25-32. https://doi.org/10.1016/S1049-9644(03)00056-2
  9. Metzgar, J. S. Schneider, H. and Pryer, K. M. 2007. Phylogeny and divergence time estimates for the fern Genus Azolla (Salviniaceae). Int. J. Plant Sci. 168: 1045-1053. https://doi.org/10.1086/519007
  10. Singh, P. K. 1977. Multiplication and utilization of fern Azolla containing nitrogen-fixing algal symbiont as green manure on rice cultivation. Riso 26: 125-137.
  11. Tamura, K., Dudley, J., Nei, M. and Kumar, S. 2007. MEGA4: Molecular evolutionary genetics analysis (MEGA) software version 4.0. Mol. Biol. Evol. 24: 1596-1599. https://doi.org/10.1093/molbev/msm092
  12. Wong Fong Sang, H. W., Vu, V. V., Kijne, J. W., Tam, V. T. and Planque, K. 1987. Use of Azolla as a test organism in a growth chamber of simple design. Plant Soil 99: 219-230. https://doi.org/10.1007/BF02370869