Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara?

Abstract Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomyces genus and five were non- Streptomyces . All isolates were screened for their in vitro antifungal activity against Rhizoctonia solani . The six that had the greatest pathogen inhibitory capacities were subsequently tested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils, and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seeds with antagonistic isolates significantly reduced ( P P Streptomyces mutabilis NBRC 12800 T (100% of similarity) and Streptomyces cyaneofuscatus JCM 4364 T (100% of similarity), respectively.