Does the combination of citrate and phytase exudation in Nicotiana tabacum promote the acquisition of endogenous soil organic phosphorus?

• Published in: Plant and soil Vol. 412; no. 1/2; pp. 43 - 59
• Main Authors: Giles, Courtney D., George, Timothy S., Brown, Lawrie K., Mezeli, Malika M., Richardson, Alan E., Shand, Charles A., Wendler, Renate, Darch, Tegan, Menezes-Blackburn, Daniel, Cooper, Patricia, Stutter, Marc I., Lumsdon, David G., Blackwell, Martin S. A., Wearing, Catherine, Zhang, Hao, Haygarth, Philip M.
• Format: Journal Article
• Language: English
• Published: Cham Springer 01.03.2017; Springer International Publishing; Springer Nature B.V
• Subjects: Accumulation; Agriculture; Biomedical and Life Sciences; citrates; Citric acid; Ecology; Environmental aspects; Enzymes; exudation; Farming systems; fungi; intercropping; Life Sciences; Monoculture; Nicotiana tabacum; Organic phosphorus; Phosphatase; Phosphatases; Phosphorus; Physiological aspects; phytases; phytomass; Plant biomass; Plant Physiology; Plant Sciences; Regular Article; Rhizosphere; Soil pH; Soil phosphorus; Soil Science & Conservation; Soils; Synergism; Tobacco; Tobacco (Plant); Transgenic plants; United Kingdom > UK; Scotland; Citrate; Rhizosphere; Phytase; Complementarity; Soil organic phosphorus; Root exudation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-016-2884-3

Background and Aims: Plant acquisition of endogenous forms of soil phosphorus (P) could reduce external P requirements in agricultural systems. This study investigated the interaction of citrate and phytase exudation in controlling the accumulation of P and depletion of soil organic P by transgenic Nicotiana tabacum plants. Methods: N. tabacum plant lines including wild-type, vector controls, transgenic plants with single-trait expression of a citrate transporter (A. thaliana frd3) or fungal phytases (phyA: A. niger, P. lycii) and crossed plant lines expressing both traits, were characterized for citrate efflux and phytase exudation. Monocultures and intercropped combinations of single-trait plants were grown in a low available P soil (12 weeks). Plant biomass, shoot P accumulation, rhizosphere soil pH and citrate-extractable-P fractions were determined. Land Equivalent Ratio and complementarity effect was determined in intercropped treatments and multiple-linearregression was used to predict shoot P accumulation based on plant exudation and soil P depletion. Results: Crossed plant lines with co-expression of citrate and phytase accumulated more shoot P than single-trait and intercropped plant treatments. Shoot P accumulation was predicted based on phytase-labile soil P, citrate efflux, and phytase activity (Rsq=0.58, P < .0001). Positive complementarity occurred between intercropped citrate-and phytase-exuding plants, with the greatest gains in shoot P occurring in plant treatments with A. niger phyA expression. Conclusions: We show for the first time that trait synergism associated with the exudation of citrate and phytase by tobacco can be linked to the improved acquisition of P and the depletion of soil organic P.