Evaluation of streptomyces and non-streptomyces actinomycetes isolates for growth promotion in Vigna radiata and their use as biocontrol agent against Sclerotium rolfsii

Abstract

Two streptomyces (ARHS/PO26 and ARHS/PO27) and two non streptomyces (ARHS/Mn3 and ARHS/Mn7) actinomycetes isolates obtained from the rhizosphere soil of Solanum tuberosum and Mangifera indica were found to be phosphate solubilizers and showed antagonistic activity against Sclerotium rolfsii. Isolates ARHS/PO26 and ARHS/PO27 were identified morphologically and confirmed by the National Centre for Fungal Taxonomy, as Streptomyces griseus (NCFT 2578.08; NAIMCC-B-00916) and Streptomyces griseolus (NCFT 2579.08). ARHS/Mn 3 and Streptomyces griseolus (ARHS/PO27) could inhibit 68% and 59.7% growth of Sclerotium rolfsii in vitro. In vivo evaluation of the isolates ARHS/Mn 3, Streptomyces griseolus (ARHS/PO27) and Streptomyces griseus (ARHS/PO26) showed maximum growth promotion on Vigna radiata by enhancing key defense enzymes like chitinase, β-1,3-glucanase, phenylalanine ammonia lyase and peroxidase. The results emphasize the fact that soil actinomycetes could be used as potential biocontrol agents.