Plant Growth Promoting Potential of Bacterial Endophytes from Medicinal Plants

Endophytic bacteria were isolated from surface sterilized parts like leaf, stem, rhizome and fruit of medicinal plants viz. Azadirachta indica, Zingiber officinale Rosc., Chlorophytum borivilianum, Curcuma longa, Tinospora cordifolia, Withania somnifera (L) Dunal and Ocimum sanctum Lin. on various nutrient media. Out of thirty isolates, the best five cultures were selected on the basis of plant growth promoting abilities viz. phosphate solubilization, potash mobilization, production of IAA and siderophore, production of various enzymes like ACC-deaminase, cellulase, protease, lipase, chitinase; antifungal activity and biochemical tests. On the basis of morphological, physiological, biochemical and molecular ribotyping, endophytes were characterized as Bacillus tequilensis strain AAU K1, Bacillus endophyticus strain AAU K2, Beijerinckia fluminensis strain AAU K3, Bacillus safensis strain AAU K4 and Pseudomonas aeruginosa strain AAU K5. Moreover, later three endophytes showed presence of nifH gene indicating nitrogen fixing ability.