Abstract

In the present investigation, four different composts were obtained from Supa Biotech (P) Ltd., Muketshwar and LRC, GBPUAT, Pantnagar, India. The highest actinomycetes community was obtained from CPP compost (67.18%), LRC (15.62%), CM (12.5 %) and VE (4.6%). A total of 48 actinomycetes isolated and examined, exhibited ability to degrade starch, solubilize phosphate, produce catalase and siderophores. Isolated actinomycetes strains were checked for their antagonistic potential against seed and soil borne plant pathogens: Fusarium oxysporum (Wilt), Colletotrichum truncatum (Anthracnose in soyabean), Colletotrichum capsici (Anthracnose in chilli) and Helminthosporium oryzae (Brown spot in rice). It restricted mycelium growth of all four pathogens: H. oryzae (61.53%), F. oxysporum (57.5%), C. truncatum (54.05%) and C. capsici (50%) under in vitro condition. A greenhouse study was performed to evaluate efficiency of CPP-53 for controlling disease incidence by F. oxysporum in tomato plants. Out of the four treatments in this experiment, significantly lowest disease severity and higher plant vigour was recorded when CPP-53 was inoculated as compared to the control plants. Observation proved the potential of strain CPP-53 under in vitro condition and as an amendment in soil leading to suppression of pathogenic effect and efficient biocontrol agent. 23S rDNA region of actinomycetes strains were sequenced and the most potent one, CPP-53 has 98% similarity with Streptomyces flavofuscus.

Key words: Siderophore production, wilt, disease severity, Streptomyces flavofuscus, 23S rDNA, biocontrol.