A - Papers appearing in refereed journals
Giles, C. D., George, T. S., Brown, L. K., Mezeli, M., Shand, C. A., Richardson, A. E., Mackay, R., Wendler, R., Darch, T., Menezes-Blackburn, D., Cooper, P., Stutter, M. I., Lumsdon, D. G., Blackwell, M. S. A., Wearing, C., Zhang, H. and Haygarth, P. M. 2017. Linking the depletion of rhizosphere phosphorus to the heterologous expression of a fungal phytase in Nicotiana tabacum as revealed by enzyme-labile P and solution 31 P NMR spectroscopy. Rhizosphere. 3, pp. 82-91.
|Authors||Giles, C. D., George, T. S., Brown, L. K., Mezeli, M., Shand, C. A., Richardson, A. E., Mackay, R., Wendler, R., Darch, T., Menezes-Blackburn, D., Cooper, P., Stutter, M. I., Lumsdon, D. G., Blackwell, M. S. A., Wearing, C., Zhang, H. and Haygarth, P. M.|
Root exudation of phytase could improve the ability of plants to access organic forms of soil phosphorus (P), thereby minimizing fertilizer requirements and improving P use efficiency in agroecosystems. After 75 days growth in a high available P soil, shoot biomass and P accumulation, soil pH, and rhizosphere P depletion were investigated in Nicotiana tabacum wild-type and transgenic plant-lines expressing and exuding Aspergillus niger phytase (ex::phyA), or a null-vector control. Solution 31P NMR analysis revealed a 7% to 11% increase in orthophosphate and a comparable depletion of undefined monoester P compounds (-13 to -18%) in the rhizosphere of tobacco plants relative to the unplanted soil control. Wild-type plants had the greatest impact on the composition of rhizosphere P based on the depletion of other monoester P, polyphosphate, and phosphonate species. The depletion of phytase-labile P by ex::phyA plants was associated with decreased proportions of other monoester P, rather than myo-InsP6 as expected. Rhizosphere pH increased from 6.0 to 6.5–6.7 in transgenic plant soils, beyond the pH optimum for A. niger phyA activity (pH=5), and may explain the limited specificity of ex::phyA plants for phytate in this soil. The efficacy of single exudation traits (e.g., phytase) therefore appear to be limited in P-replete soil conditions and may be improved where soil pH matches the functional requirements of the enzyme or trait of interest.
|Keywords||Phosphorus; Phytate; Phytase; Tobacco; 31P NMR spectroscopy; pH|
|Year of Publication||2017|
|Journal citation||3, pp. 82-91|
|Digital Object Identifier (DOI)||doi:10.1016/j.rhisph.2016.11.004|
|Open access||Published as non-open access|
|Funder||Biotechnology and Biological Sciences Research Council|
|Funder project or code||Organic P utilization in soils (OPUS)|
|Online||08 Dec 2016|
|Publication process dates|
|Accepted||30 Nov 2016|
|Copyright license||CC BY|
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