Identification and bio-control activity of Streptomyces strain (Koyanogensis) against Magnaporthe grisea

Abstract

Rice blast is a major threat to the rice crop in rice-growing areas around the globe. However, synthetic fungicides are injurious for the ecosystem and the existing bio-control agents facing the resistance from the pathogens. In this study, an isolated novel Streptomyces strain (TA-47), from the rice field was identified by culturing on different media, physiological tests, biochemical tests, chemo-taxonomy and molecular biological approaches. In-vitro and in-vivo bio-control activity of the isolated strain was evaluated. Growth on the media, spore production, utilization of sole carbon and nitrogen sources, presence of diaminopimelic acid (DAP) in the cell wall of the strain and fatty acid production were observed.16S rRNA (gene sequence) and a neighbour-joining hood tree indicated that the strain TA-47 is Streptomyces koyanogensis. In-vitro inhibition zone of 29 mm against the M. grisea showed the antagonistic potential of the novel strain TA-47. On the other hand, in the in-vivo studies, strain TA-47, showed the strong bio-control effect, as disease severity decreased to 19.66 ± 1.6%, while in the non-treated sample the disease severity was recorded as 44.66 ± 5.249%. Moreover, after the treatment of the strain, effects on the growth, such as increased height and root length by 72.22 and 16.54 cm, respectively, were also recorded. In conclusion, rhizosphere Streptomyces TA-47, was a novel Streptomyces koyanogensis strain. The study found that the strain had strong bio-control and growth-promoting abilities. Abbreviation: M Grisea, Magnaporthe grisea; ISP, International Streptomyces Project; PDA, Potato Dextrose AgarSEM, Scan Electron Microscope; TLC, Thin Layer Chromatography; GC-MS, Gas Chromatography Mass Spectrum

Keywords

• rice blast
• magnaporthe grisea
• streptomyces koyanogensis
• bio-control