V.P. GHODAKE, S.A. PATIL, P.P. PATTEKARI, P.A. DHUMAL AND S.D. KHAMBE
Abstract
In this study Rhizobium sp. was isolated from root nodules of fenugreek (Trigonella foenum-graecum) and Identified as Rhizobium meliloti following standard methods. This isolate was tested for the production of indole acetic acid (IAA). Detection of IAA was done with TLC where a specific spot from the extracted IAA preparation was found, corresponding with the standard spot of IAA with same Rf value. The addition of L. tryptophan (as a precursor for auxins) to the medium inoculated with Rhizobium meliloti, enhanced the production of IAA several fold compared to L-tryptophan non-amended medium. Moreover, the present results support the consensus that the tryptophan dependent pathway plays vital role to maintain very high IAA levels. The temperature 30°C, pH 7.0 and 0.4 % tryptophan concentration in, the medium was found optimum for the production of IAA by Rhizobium meliloti. Production of IAA by Rinzobium meliloti increased with an increase in tryptophan concentration from 1 to 4- mg/mL.