A New Enrichment Method for the Selective Isolation of Streptomycetes from the Root Surfaces of Herbaceous Plants

Abstract

Diverse rhizoplane streptomycetes with high levels of anti-phytopathogenic activity were efficiently isolated from healthy herbaceous plants using a new enrichment method, which we designated as the moist incubation and desiccation (MI&D) method. The MI&D method involves incubating root tissues on humic acid-vitamin (HV) agar, desiccating roots bearing arthrospore chains of colonized streptomycetes in dried soil particles, then liberating spores by agitation in water. Dilutions of the liquid enriched with streptomycete spores are then plated and incubated on HV agar. The desiccation stage drastically reduces bacterial contamination, thereby achieving selective isolation of streptomycetes.