Isolation of Rhizobacteria from Jatropha curcas and characterization of produced ACC deaminase

Decreased levels of ACC (1-aminocyclopropane-1-carboxylic acid) result in lower levels of endogenous ethylene, which eliminate the potentially inhibitory effects of stress-induced higher ethylene concentrations. It is worth noting the substantial ability of the bacterial species to colonize different environments, including taxonomically distinct plants cultivated in distantly separated geographical regions. For example, Enterobacter cloacae, designated as MSA1 and Enterobacter cancerogenus, designated as MSA2 were recovered from the rhizosphere of Jatropha in the present work. This study first time confirms the ACC deaminase activity in the Enterobacter cancerogenus on the preliminary basis. Several bacterial plant growth-promoting mechanisms were analyzed and detected like phosphate solubilization, siderophore production, IAA production, GA3 (gibberellic acid) production and ACC deaminase activity in the isolated cultures. Isolates were grown until exponential growth phase to evaluate their ACC deaminase activity and the effect of pH, temperature, salt, metals and substrate concentration after the partial purification of enzyme by ion exchange chromatography. The FOURIER TRANSFORM INFRARED (FT-IR) spectra were recorded for the confirmation of a-ketobutyrate production. By using lineweaver Burk plot Km and Vmax value for ACC deaminase of both the organism was calculated in the different fractions. In this work, we discuss the possible implications of these bacterial mechanisms on the plant growth promotion or homeostasis regulation in natural conditions. ((c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)