Endophytic Streptomyces-How they help plants

Streptomyces sp. is genus under Actinomycetes, and is considered largest in the phylum, actinobacteria. There has been considerable research on Actinomycetes and Streptomyces owing to their ability to produce potent antibiotic metabolites of high clinical, biological and economic value. The Streptomyces sp. can be both soil dwelling or endophytic in nature and both have attributes to undertake plant growth promotion owing to their ability to produce bioactive compounds as secondary metabolite. The endophytic Streptomyces in particular assist in plant growth promotion and bio control through direct or indirect mediation. The mode may involve secretion of enzymes or compounds to directly affect the pathogen or colonization of host tissues thus evoking the mechanism of SAR and ISR supportive of the primary and secondary defense mechanism of any plant tissue system. The occurrence of endophytic Streptomyces among all host particularly in medicinal plants, their isolation and study may be highly beneficial as medicinal plants themselves have attributes that assist in biocontrol and plant growth promotion.