Keywords: Streptomyces, Xanthomonas oryzae pv. oryzae, antimicrobial, MIC.


Streptomyces are prokaryotic microorganisms capable of producing a wide range of secondary metabolites has the capacity to fight with the competing plant pathogens and suppress the growth of them. A promising Streptomyces sp. TC1 isolate exhibited antimicrobial activity against bacterial leaf blight pathogen Xanthomonas oryzae pv. oryzae under in vitro conditions. The antimicrobial activity of TC1 culture filtrate was found to be higher at seven days of incubation. The optimized extraction of antimicrobial fractions from the culture filtrate was obtained with ethyl acetate solvent. Adjusting the pH of the culture filtrate to 3 prior to extraction process resulted in increased recovery of antimicrobial fractions. The crude antimicrobial fraction obtained from the TC1 fermentation broth exhibited a minimum inhibitory concentration value of 300 µg/ml against the test pathogen Xanthomonas oryzae pv. oryzae. The antimicrobial activity results including agar well diffusion assay and MIC experiments strongly recommend that the Streptomyces sp. TC1 can be explored for antimicrobial metabolites for bacterial blight disease control in rice.


Ahmed, A.A. 2007. Production of antimicrobial agent by Streptomyces violachromogenes. Saudi J. Biol. Sci., 14 (1): 7-16.
Chand, T., Singh, N., Singh, H. and Thind. B.S. 1979. Field efficacy of stable bleaching powder to control bacterial blight of rice. Int. Rice Res. Newsl., 4: 12.
El-Abyad, M.S., El-Sayed, M.A., El-Shanshoury, A.R. and El- Sabbagh, S.M. 1993. Towards the biological control of fungal and bacterial diseases of tomato using antagonistic Streptomyces spp. Plant and Soil, 149:185-195.
Embley, T.M. and Stackebrandt, E. 1994. The molecular phylogeny and systematics of the actinomycetes. Ann. Rev. Microbiol., 48: 257-289.
Gnanamanickam, S.S., Priyadarisini, V.B., Narayanan, N.N., Preeti, V. and Kavitha, S. 1999. An overview of bacterial blight disease of rice and strategies for its management. Curr. Sci., 77(11): 1435-1443.
Hoa, P.T.P., Quang, N.D., Sakiyama, Y., Hop, D.V., Hang, D.T., Ha, T.H., Van, N.T., Kim Quy, N.T. and Anh Dao, N.T. 2012. Screening for actinomyces isolated from soil with the ability to inhibit Xanthomonas oryzae pv. oryzae causing rice bacterial blight disease in Vietnam. Afr. J. Biotechnol., 11(80): 14586-14594.
Islam, R., Jeong, Y.T., Ryu, Y.J., Song, C.H. and Lee, Y.S. 2009. Isolation, identification and optimal culture conditions of Streptomyces albidoflavus C247 producing antifungal agents against Rhizoctonia solani AG2-2. Mycobiol., 37(2) : 114-120.
Jain, R., Zaidi, K.U., Parveen, N. and Saxena, A. 2011. Optimization of cultural conditions for the production of antibiotic by Streptomyces sp. VRY-1. Recent Res. Sci. Technol., 3(10): 81-87.
Jennifer Emelda, E. and Vijayalakshmi, N. 2012. Isolation and screening of antibiotic producing soil actinomycete for antimicrobial activity. Dev. Microbiol. Mol. Biol., 3(1): 47-54.
Lim, C., Kim, J., Choi, J.N., Ponnusamy, K., Jeon, Y., Kim, S.U., Kim, J.G. and Lee, C. 2010. Identification, fermentation, and bioactivity against Xanthomonas oryzae of antimicrobial metabolites isolated from Phomopsis longicolla S1B4. J. Microbiol. Biotechnol., 20 (3): 494-500.
Liu, C.M., Westley, J.W., Herman, T.E., Prasser, B.L.T., Palleroni, N., Evans, R.H. and Miller, P.H. 1986. Novel polyether antibiotics X- 14873 A, G and H produced by Streptomyces. Taxonomy of the producing culture, fermentation, biological and inosphores properties of antibiotics. J. Antibiot., 39(12): 1712-1718.
Marimuthu, T., Ganapathy, T., Ramadoss, N. and Raghupathi, N. 1999. Management of bacterial leaf blight. Vistas of Rice Research, Tamil Nadu Agricultural University, Coimbatore. pp 493-495.
Marshall, S.A., Jones, R.N., Wanger, A., Washington, J.A., Doern, G.V., Leber, A.L. and Haugen, T.H. 1996. Proposed MIC quality control guidelines for national committee for clinical laboratory standards susceptibility tests using seven veterinary antimicrobial agents: Ceftiofur, Enrofloxacin, Florfenicol, Penicillin G-Novobiocin, Pirlimycin, Premafloxacin, and Spectinomycin. J. Clin. Microbiol., 34 (8): 2027-2029.
Mew, T.W., Alaverz, A.M., Leach, J.E. and Swings, J. 1993. Focus on bacterial blight of rice. Plant Dis., 77: 5-12.
Miyadoh, S. 1993. Research on antibiotic screening in Japan over the last decade. A producing microorganism approach. Actinomycetologica, 9: 100-106.
Mohanraj, G. and Sekar, T. 2013. Antagonistic activity of marine Streptomyces sp. LCJ94 against the shrimp pathogens. Annals Biol. Res., 4(4): 224-227.
Mustafa, S.A., Tamer, U.A. and Azer, C. 2004. Antibacterial activity of some actinomycetes isolated from farming soils of Turkey. Afr. J. Biotechnol., 3(9): 441-446.
National Committee for Clinical Laboratory Standards. 2000. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically, 5th ed.; Approved Standard (M7A5); National Committee for Clinical Laboratory Standards: Wayne, PA.
Park, S.B., Lee, I.A. and Suh, J.W. 2011. Screening and identification of antimicrobial compounds from Streptomyces bottropensis suppressing rice bacterial blight. J. Microbiol. Biotechnol., 21(12):1236-42.
Perez, C., Paul, M. and Bazerque, P. 1990. An antibiotic assay by the agar well diffusion method. Acta. Biol. Med. Exp., 15: 113-115.
Rao, P.S. and Kauffman, H.E. 1977. Potential yield losses in dwarf rice varieties due to bacterial leaf blight in India. Phytopathol. Z., 90: 281-284.
Saha, M.R., Ripa, F.A., Islam, M.Z. and Khondkar, P. 2010. Optimization of conditions and in vitro antibacterial activity of secondary metabolite isolated from Streptomyces sp. MNK7. J. Appl. Sci. Res., 6(5): 453-459.
Seki, M. and Mizukami, T. 1956. Application of antibiotics against bacterial leaf blight of rice plant. Kyushu Agric. Res., 17: 98.
Shanmugaiah, V., Mathivanan, N. and Varghese, B. 2010. Purification, crystal structure and antimicrobial activity of phenazine-1-carboxamide produced by a growth-promoting biocontrol bacterium, Pseudomonas aeruginosa MML2212. J. Appl. Microbiol., 108(2): 703-711.
Sosovele, M.E., Hosea, K.M. and Lyimo, T.J. 2012. In vitro antimicrobial activity of crude extracts from marine Streptomyces isolated from mangrove sediments of Tanzania. J. Biochem. Tech., 3(4): 431-435.
Tanaka, Y. and Omura, S. 1993. Agroactive compounds of microbial origin. Annu. Rev. Microbiol., 47: 57-87.
Usha Rakshanya, J., Hemashenpagam, N. and Kanchana Devi, D. 2011. Purification of secondary metabolites from soil actinomycetes. Intl. J. Microbiol. Res., 3(3):148-156.
Velusamy, P., Immanuel, J.E., Gnanamanickam, S.S. and Thomashow, L. 2006. Biological control of rice bacterial blight by plant-associated bacteria producing 2,4-diacetylphloroglucinol. Can. J. Microbiol., 52: 56-65.
Weller, D.M. 1988. Biological control of soil-borne plant pathogens in the rhizosphere with bacteria. Ann. Rev. Phytopathol., 26: 379-407.
Westley, J.W., Evans, R.H., Sello, L.H., Troupe, N., Liu, C.M. and Blount, J.F. 1979. Isolation and characterization of antibiotic X-14547A, a novel monocarboxylic acid ionophore produced by Streptomyces antibioticus NRRL 8167. J. Antibiot., 32:100-107.
Xu, L., Li, O. and Jaing, G.L. 1996. Diversity of soil actinomycetes in Yunnan China. Appl. Environ. Microbiol., 62: 244-248.