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, 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.

Jha CK ，Annapurna K ，Saraf M 《-》

Stimulation of the growth of Jatropha curcas by the plant growth promoting bacterium Enterobacter cancerogenus MSA2.

Jha CK ，Patel B ，Saraf M 《-》

Characterization of ACC deaminase gene in Pseudomonas entomophila strain PS-PJH isolated from the rhizosphere soil.

Kamala-Kannan S ，Lee KJ ，Park SM ，Chae JC ，Yun BS ，Lee YH ，Park YJ ，Oh BT ... -  《-》

A halotolerant Enterobacter sp. displaying ACC deaminase activity promotes rice seedling growth under salt stress.

Agricultural productivity is proven to be hampered by the synthesis of reactive oxygen species (ROS) and production of stress-induced ethylene under salinity stress. One-aminocyclopropane-1-carboxylic acid (ACC) is the direct precursor of ethylene synthesized by plants. Bacteria possessing ACC deaminase activity can use ACC as a nitrogen source preventing ethylene production. Several salt-tolerant bacterial strains displaying ACC deaminase activity were isolated from rice fields, and their plant growth-promoting (PGP) properties were determined. Among them, strain P23, identified as an Enterobacter sp. based on phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry data and the 16S rDNA sequence, was selected as the best-performing isolate for several PGP traits, including phosphate solubilization, IAA production, siderophore production, HCN production, etc. Enterobacter sp. P23 was shown to promote rice seedling growth under salt stress, and this effect was correlated with a decrease in antioxidant enzymes and stress-induced ethylene. Isolation of an acdS mutant strain enabled concluding that the reduction in stress-induced ethylene content after inoculation of strain P23 was linked to ACC deaminase activity.

Sarkar A ，Ghosh PK ，Pramanik K ，Mitra S ，Soren T ，Pandey S ，Mondal MH ，Maiti TK ... -  《-》

Isolation and characterization of ACC deaminase genes from two different plant growth-promoting rhizobacteria.

Shah S ，Li J ，Moffatt BA ，Glick BR ... -  《CANADIAN JOURNAL OF MICROBIOLOGY》