Nutrient competition mediated antagonism of microbes against Rhizoctonia solani

Abstract

Plant growth-promoting (PGP) microorganisms are beneficial soil micro creatures which may facilitate plant growth by direct or indirect ways. Bacillus amyloliquefaciens MB101 (BA), Streptomyces atrovirens N23 (SA) and Hypocrea lixii NAIMCC-F-01760 (HL) were earlier reported to have the ability to manage the tomato root rot disease caused by Rhizoctonia solani (RS) at some extent. In the present study, effect of nutrient supplementation like potato dextrose broth (PDB) and tomato root extract (TRE) on antagonism of these three microbes was characterized under the soil microcosm in order to understand the role of nutrient in microbe-microbe interaction. A moderate influence on the population of all three antagonists was resulted by PDB and TRE with RS. However, TRE and PDB were causing a significant impact on cell wall degrading enzymes and antifungal activity in the presence of RS. Moreover, hyphal degradation of RS was proved by scanning electron micrographs in the absence of substrates. Nutrient competition enhanced the call wall degrading enzyme production. Therefore, the present study concluded the role of substrate in the mycoparasitism and also sustain the potential of the hereby methodology (soil microcosm) for screening of other soil-inhibiting organism in the future.