Molecular Characterization and Biocontrol Potentiality of Actinomycete Against Rice Sheath Blight Pathogen, Rhizoctonia solani

摘要

Actinomycetes were isolated from rice rhizo-sphere and isolates were putatively selected based on characteristic colony morphology, 16S rDNAand ARDRA confirmed their identification as actinobacteria. Isolates were belonged either to Strep-tomyces spp.or Actinopolymorpha spp. Under in vitro condition, isolates IABT-A1, IABT-A2, IABT-A3, IABT-A6. IABT-A7, IABT-A8 and IABT-A9 showed 98-100% inhibition of Rhizoctonia solani, rice sheath blight pathogen. Further, five isolates were evaluated under glasshouse condition and the potent actinobacteria against rice sheath blight was identified. Among these isolates, IABT-A7 (Actinopoymorpha spp.) was most effective and application as seed treatment, soil and foliar spray wasfound most promising in terms of disease reduction and plant growth promotion. Actinopoymorpha spp. (IABT-A7) enhanced plant height, root length and root biomass in addition to reduced sheath blight infection in rice. This result indicates the role of actinobacteria isolate IABT-A7, as the probable stimulator of ISR (Induced Systemic Resistance) signaling pathway involved in plant disease resistance.