Assessment of functional diversity and structure of phytate-hydrolysing bacterial community in Lolium perenne rhizosphere

Abstract

Background and aims Plant growth is frequently limited by the availability of inorganic phosphorus (P) in the soil. In most soils, a considerable amount of the soil P is bound to organic molecules. Of these, phytate is the most abundant identifiable organic P form, but is not readily available to plants. In contrast, microorganisms have been shown to degrade phytate with high efficiency. The current study aims to characterize the members of the phytate-hydrolysing bacterial community in rhizosphere, and the molecular and enzymatic ability of these bacteria to degrade phytate. Methods and resultsThe phytate-hydrolysing bacterial community was characterized from the rhizosphere of plants cultivated in the presence or absence of phytate supplementation. Major changes in the bacterial community structure were observed with both culturedependent and -independent methods, which highlighted the predominance of Proteobacteria and Actinobacteria. Phytase activity was detected for a range of rhizobacterial isolates as well as the presence of, β-propeller phytases (BPP) for both isolates and directly in a soil sample. Conclusion A wide taxonomic range of functional phytate utilizers have been discovered, in soil bacterial taxa that were previously not well known for their ability to utilise phytate as P or C sources. This study provides new insights into microbial carbon and phosphorus cycling in soil.

A novel microcosm for recruiting inherently competitive biofertilizer-candidate microorganisms from soil environments

“…Likewise, our findings of Firmicutes in the Ca-IP6+RE hotspots fit with previous studies showing that the phyla, and specifically the genus Bacillus, responds quickly to additions of organic material ; (Fierer et al 2007). Finally, our Ca-IP6 hotspot findings further compliment the findings by Sanguin et al (2016) who employed a culture-independent 16S rRNA gene-DGGE study of the grass rhizosphere, and showed predominance of Proteobacteria and Actinobacteria in Na-phytate treated alkaline soils.…”

“…Third, the BPP primers employed do not cover enough sequence variability to capture the full BPP profile. Whilst there have been various attempts to develop degenerate BPP primers (Huang et al, 2009, Jorquera et al, 2013, Lim et al, 2007; a broad consensus remains however that the currently available primers are unable to capture the BPP profile believed to be present based on in-vitro evidence (Sanguin et al 2016). Finally, there is the possibility that another novel or overlooked phytase acts in alkaline-buffered systems.…”

Functional and molecular characterization of plant growth promoting Bacillus isolates from tomato rhizosphere

“…Some species of bacteria, including Bacillus spp., possess the ability to mineralize and solubilize organic and inorganic phosphorus in the soil for quick access to the plant ( Barea and Richardson, 2015 ). Microbial phytases, specially produced by Bacillus spp., were studied due to their PGP effects and diverse agrobiotechnological applications ( Kumar et al., 2013 ; Sanguin et al., 2016 ). Besides solubilizing phytate phosphorous, extracellular phytases produced by Bacillus spp.…”

A novel microcosm to identify inherently competitive microorganisms with the ability to mineralize phytate in solum

“…Third, the BPP primers employed do not cover enough sequence variability to capture the full BPP profile. While there have been various attempts to develop degenerate BPP primers (Huang et al, 2009, Jorquera et al, 2013, Lim et al, 2007; a broad consensus remains that the currently-available primers are unable to capture the BPP profile believed to be present based on in-vitro evidence (Sanguin et al, 2016). Finally, there is the possibility that another novel or overlooked phytase acts in alkaline-buffered systems.…”