scholarly journals Characterization and optimization of 1-Aminocyclopropane-1-Carboxylate Deaminase (ACCD) activity in different rhizospheric PGPR along with Microbacterium sp. strain ECI-12A

2013 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Umesh P. Shrivastava ◽  
Ashok Kumar

A total of nine strains of plant growth promoting rhizobacteria were analyzed for ACC deaminase activity, where highest ACC deaminase activity was found in Klebsiella sp strain ECI-10A (539.1 nmol α-keto butyrate/ mg protein/ h) and lowest in Microbacterium sp strain ECI-12A (122.0 nmol α-keto butyrate/ mg protein/ h). Although Microbacterium sp strain ECI-12A showed lowest level of ACC deaminase activity, but, the species of Microbacterium isolated from rhizosphere is the first report. Microbacterium sp strain ECI-12A was also analyzed under varying conditions of time, amount of 1-Aminocyclopropane-1- carboxylate (ACC), and temperature for optimization of the ACC deaminase activity. The optimum activity was recorded with the supplementation of 5mM ACC at 30°C temperature after 24h of culture growth. All the nine strains showed acdS gene in the PCR amplification of that gene. No any rhizospheric Microbacterium species showing ACC deaminase activity have been reported earlier, therefore, we report here ACC deaminase activity in Microbacterium sp ECI-12A isolated from rice rhizosphere is a novel finding. DOI: http://dx.doi.org/10.3126/ijasbt.v1i1.7921 Int J Appl Sci Biotechnol, 2013, Vol. 1(1): 11-15

2008 ◽  
Vol 57 (4) ◽  
pp. 312-317 ◽  
Author(s):  
Venkadasamy Govindasamy ◽  
Murugesan Senthilkumar ◽  
Kishore Gaikwad ◽  
Kannepalli Annapurna

1998 ◽  
Vol 44 (9) ◽  
pp. 833-843 ◽  
Author(s):  
Salehuzzaman Shah ◽  
Jiping Li ◽  
Barbara A Moffatt ◽  
Bernard R Glick

We have recently proposed that one way that plant growth-promoting rhizobacteria (PGPR) stimulate plant growth is through the activity of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which causes a lowering of plant ethylene levels resulting in longer roots. As part of an effort to understand the role of this enzyme in PGPR, the genes for ACC deaminase from two PGPR, Enterobacter cloacae CAL2 and UW4, have been isolated. These genes are highly homologous to the ACC deaminase genes from Pseudomonas strains 6G5 and F17 and similar to the ACC deaminase gene from Pseudomonas sp. strain ACP. The region downstream (i.e., at the 3'-terminal end) of the strain UW4 ACC deaminase gene has a potential hairpin-like transcription termination site. The regions upstream of the strains UW4 and CAL2 ACC deaminase genes contain putative ribosome-binding sites; however, the promoter sequences have not yet been identified. Southern hybridization experiments suggest that there is a single copy of the ACC deaminase gene in Enterobacter cloacae strains UW4 and CAL2 and that there may be several different types of ACC deaminase genes in different microbes. The cloned ACC deaminase gene can be expressed in Escherichia coli enabling this bacterium to grow on ACC as a sole source of nitrogen and confers upon both Escherichia coli and Pseudomonas spp. strains that are transformed with this gene the ability to promote the elongation of the roots of canola seedlings.Key words: plant growth-promoting rhizobacteria, PGPR, 1-aminocyclopropane-1-carboxylate, ACC, ACC deaminase, ethylene, soil bacteria.


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