%0 Journal Article
%T Evaluation of Phytase Producing Bacteria for Their Plant Growth Promoting Activities
%A Prashant Singh
%A Vinod Kumar
%A Sanjeev Agrawal
%J International Journal of Microbiology
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/426483
%X Bacterial inoculants are known to possess plant growth promoting abilities and have potential as liquid biofertilizer application. Four phytase producing bacterial isolates (phytase activity in the range of 0.076¨C0.174£¿U/mL), identified as Advenella species (PB-05, PB-06, and PB-10) and Cellulosimicrobium sp. PB-09, were analyzed for their plant growth promoting activities like siderophore production, IAA production, HCN production, ammonia production, phosphate solubilization, and antifungal activity. All isolates were positive for the above characteristics except for HCN production. The solubilization index for phosphorus on Pikovskaya agar plates was in the range of 2¨C4. Significant amount of IAA (7.19 to 35.03£¿¦Ìg/mL) production and solubilized phosphate (189.53 to 746.84£¿¦Ìg/mL) was noticed by these isolates at different time intervals. Besides that, a greenhouse study was also conducted with Indian mustard to evaluate the potential of these isolates to promote plant growth. Effect of seed bacterization on various plant growth parameters and P uptake by plant were used as indicators. The plant growth promoting ability of bacterial isolates in pot experiments was correlated to IAA production, phosphate solubilization, and other in vitro tests. On the basis of present findings, isolate PB-06 was most promising in plant growth promotion with multiple growth promoting characteristics. 1. Introduction It is well known that a considerable number of bacterial species, mostly those associated with the plant rhizosphere, are able to exert a beneficial effect upon plant growth. Therefore, their use as biofertilizers or control agents for agriculture improvement has been a focus of numerous researchers for a number of years. Bacterial inoculants have been used to increase plant yields in several countries, and commercial products are currently available. For example, in India, several biofertilizers are commercially produced and employed with different crops, mostly using strains of Azotobacter, Rhizobium, Azospirillum, and Burkholderia. Several possible mechanisms have been proposed, including suppression of diseases caused by plant pathogens [1], competition with pathogenic microorganisms by colonizing roots [2], production of plant-growth-regulating substances such as indole-3-acetic acid (IAA) [3], and lowering ethylene levels in root cells. Plant-stimulatory effects exerted by plant growth promoting bacteria (PGPB) might also be due to an enhanced availability of limited plant nutrients such as nitrogen, phosphorus, B-vitamins, and amino acids in the
%U http://www.hindawi.com/journals/ijmicro/2014/426483/