Enhanced phosphorus uptake in transgenic tobacco plants that overproduce citrate

Phosphorus (P) is one of the most important nutrients limiting agricultural production worldwide. In acid and alkaline soils, which make up over 70% of the world's arable land, P forms insoluble compounds that are not available for plant use. To reduce P deficiencies and ensure plant productivity, nearly 30 million tons of P fertilizer are applied every year. Up to 80% of the applied P fertilizer is lost because it becomes immobile and unavailable for plant uptake. Therefore, the development of novel plant varieties more efficient in the use of P represents the best alternative to reduce the use of P fertilizers and achieve a more sustainable agriculture. We show here that the ability to use insoluble P compounds can be significantly enhanced by engineering plants to produce more organic acids. Our results show that when compared to the controls, citrate-overproducing plants yield more leaf and fruit biomass when grown under P-limiting conditions and require less P fertilizer to achieve optimal growth.