Abstract

BIO-PROSPECTING OF ENDOPHYTIC BACTERIA FROM MEDICINAL PLANT

Subashini G.*, Bhuvaneswari.S and Sunganya.T

Abstract

Plants are generally associated with diverse microorganisms. Endophytic organisms are those that colonize the plant internal tissue showing no external sign of infection or negative effect on there. Endophytic microbes from medicinal plants are good source of functional metabolites. Endophytic microorganisms can be derived from any part of the plant like bark, leaves, flowers, fruits, roots, seeds etc. In the present study, efforts have been made to isolate and physiological activity of endophytic bacteria inhabiting leaves of medicinal plants such as Kasarali (Catharanthus roseus L.), Thuthuvalai (Solanum trilobatum L. ) and Tulsi (Ocimum sanctum L.) which are growing in the Trichy region. The density of endophytic populations recovered in nutrient agar medium, which varied from 4.26 x 105 to 1.34 x 105 CFUg-1 per fresh weight. Colonization frequency and isolation rates 42.22, 37.78, 46.67 % and 21.05%, 17.65% and 23.81% in kasarali, thuthuvalai and tulsi respectively. Among the 12 isolates, KA-1, KA-2, KA-3, TV-5, TV-7, TL-8, TL-9 AND TL-11 were identified as Bacillus sp. KA-4, TV-6 and TL-10 were identified as Pseudomonas sp and TL-12 as Klebsiella sp. Among the 12 isolates, 9 isolates had amylolytic, lipolytic and proteolytic activity with different zone of clearance. Among the 12 isolates, 11isolates had cellulolytic activity with different zone of clearance. Among the 12 isolates, nine isolates showed antibacterial activity against either gram-positive or gram-negative bacteria. The endophytic bacterial extracts were more effective in gram-positive bacteria than gram-negative bacteria. The MIC of ethyl acetate of endophytic bacterial isolates were ranged from 3.13 to 50 mg/ml. Endophytes isolated form medicinal plants may be beneficial to the host. The endophytic microorganisms are a very promising source for production of bioactive compounds.

Keywords: Solanum trilobatum L., Catharanthus roseus L., Ocimum sanctum L.