A novel Enterobacter cancerogenus MSA2 is a plant growth promoting gamma-proteobacterium that was isolated from the rhizosphere of Jatropha cucas a potentially important biofuel feed stock plant. Based on phenotypic, physiological, biochemical and phylogenetic studies, strain MSA2 could be classified as a member of E. cancerogenus. However, comparisons of characteristics with other known species of the genus Enterobacter suggested that strain MSA2 could be a novel PGPB strain. In vitro studies were carried for the plant growth promoting attribute of this culture. It tested positive for ACC (1-aminocyclopropane-1-carboxylic acid) deaminase production, phytase, phosphate solubilization, IAA (Indole acetic acid) production, siderophore, and ammonia production. The isolate was then used as a inoculant for the vegetative study of Jatropha curcas plant. Enterobacter cancerogenus MSA2 supplemented with 1% carboxymethylcellulose showed overall plant growth promotion effect resulting in enhanced root length (124.14%), fresh root mass (81%), fresh shoot mass (120.02%), dry root mass (124%), dry shoot mass (105.54%), number of leaf (30.72%), chlorophyll content (50.41%), and biomass (87.20%) over control under the days of experimental observation. This study was designed for 120 days and was in triplicate and the data was collected at every 30 days.

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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, GA(3) (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 α-ketobutyrate production. By using lineweaver Burk plot K(m) and V(max) 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.

The extensive and enduring challenges in soil microbiology depend on the development of efficient methods to be acquainted with the types of microbes present in soil, and to determine the functional performance of the overall microbial groups in situ. This study aims to investigate the combined uses of species richness and diversity as well as to estimate the combinatorial effect of species richness and diversity in order to understand their role and distribution in their habitat. To achieve this objective a study was designed targeting the rhizosphere of Jatropha curcas L. which were planted in various soil conditions on five distinctive sites of Gujarat state (India). These sites were constantly monitored and studied for the species richness and evenness ("heterogeneity"). The isolates were checked for their PGPR potentials like Phosphate solubilisation, Siderophore production, Indole acetic acid production, ACC deaminase production, HCN production, EPS production and Ammonia production. The results obtained were used to calculate richness, evenness and diversity indices. Results reveal the total heterogeneity in the site of fertile Jatropha rhizosphere (GS4) as well as sodic soil site (GS5) than other three sites. Absence of equitability under the selected and defined condition was also observed in GS4 and GS5 sites. The combinatorial estimates provide the information on their distribution and roles in the habitat. In particular, such an empirical relationship from a single rhizosphere of a distinctive species Jatropha is useful to test diversity predictions in natural sites, and further it can be applied to either by performing trials over larger spatial and temporal scales or by conducting correlational studies of biodiversity gradients.

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