title: Factors affecting antifungal activity of Streptomyces philanthi RM-1-138 against Rhizoctonia solani.
abstract: Sheath blight disease of rice caused by Rhizoctonia solani Kühn is economically important disease in most of the world's rice growing areas. The disease causes severe yield losses of >20% of rice in Thailand. Our previous investigation reported the antifungal activity of Streptomyces philanthi RM-1-138 against R. solani PTRRC-9. In this study, glucose yeast-malt extract medium, initial pH of 7.5 and a temperature of 30 °C were found to be optimum for both cell growth and antifungal activity of S. philanthi RM-1-138. The inhibition of 94 and 100% on the growth of R. solani PTRRC-9 were achieved from the antifungal metabolites of the 6 and 9-days-old culture filtrates of S. philanthi RM-1-138, respectively. Heat treatment on the culture filtrate had slight effect on its antifungal activity. The culture broth demonstrated higher antifungal activity on growth of R. solani PTRRC-9 (90.4%) than the culture filtrate (31.5%) and its effective dose was at 0.1% (v/v). The present results indicated the possibilities of using either the culture broth or culture filtrate of S. philanthi RM-1-138 to inhibit growth of R. solani PTRRC-9.
authors.affiliation: Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, 90112, Thailand, biotec_ph@hotmail.com.
authors.forename: Sawai
authors.initials: S
authors.lastname: Boukaew
authors.forename: Poonsuk
authors.initials: P
authors.lastname: Prasertsan
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D012232:Rhizoctonia / Q000187:drug effects / Q000254:growth & development*; D013302:Streptomyces / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D013696:Temperature; D013785:Thailand
chemical_list: D000935:Antifungal Agents; D003470:Culture Media