Isolation and Characterization of Actinomycetes from Different Forest Medicinal Plants and Their Influence on Plant Growth Promotion of Costus igneus

Ancient Indian literature incorporates a remarkably broad definition of medicinal plants and considers all plants as potential sources of medicinal substances. A Total of 112 actinomycetes strains were isolated from the rhizosphere of forest (Pakhal forest) medicinal plants viz., Calycopteris floribunda(CFB), Maeruga oblongifolia (MO), Lantana camara (LC), Schleichera oleosa (SO), and Zingiber officinale (ZO), Ocimum sanctum (DM), Telangana State, India. All the isolates were tested for plant growth promoting (PGP) activities like ammonia production, indole acetic acid (IAA) production, HCN production, phosphate solubilization, seed germination test, antifungal activity and extracellular enzyme production. From a total of 112 bacterial strains isolated, number of positive isolates for each of PGP activities varied greatly. 82(73%) isolates were showing Ammonia production, 84 (75%) isolates were showing IAA production, 41 (36%) for HCN and 46 (41%) for phosphate solubilization. Pot experiments were designed and conducted on Costus igneus by using selected PGPA strains individual and in combination treatments i.e Agromyces (DM-10), and Streptomonas sp. (DM-22). (DM-10+DM-22) recorded maximum plant height, number of branches, fresh and dry weight of the plants in individual as well as combination treatments in Costus. Selected parameters subjected to ANOVA analysis by least significance difference (LSD) test at 5% level of significance. Selected PGPA strains exhibited good PGP activities. It enhanced growth parameters of Costus. It showed excellent root colonization ability. our results suggest that simultaneous screening of actinomycetes for plant growth promoting activities is a good tool to select effective PGP actinomycetes for biofertilizer development.