Crop Response to Low Phosphorus Bioavailability with a Focus on Tomato

Tomato (Solanum lycopersicum L.) is a high-value crop that has potential to enhance its P-use efficiency. While phosphorus (P) is an essential nutrient, supplies are finite and much of the P supply in agricultural soils is not bioavailable after application due to reactions such as soil adsorption, immobilization, or precipitation. Low-P bioavailability results in reduced growth, so plants may mobilize soil-bound P by altering root morphology, exuding root-derived compounds, or forming symbiosis with microorganisms. This review discusses (i) the significance of P in plants and agroecosystems, (ii) within-plant response to changing P bioavailabilities, and (iii) strategies to enhance P-acquisition efficiency (PAE). Phosphorus forms fluctuate in the soil and potential approaches to increase the bioavailable pool of P may focus on processes such as desorption, mineralization, or dissolving precipitated P-compounds. To enhance these processes, roots may alter their spatial arrangement, exude protons to acidify the rhizosphere, exude carboxylates to solubilize bound-P, exude phosphatase to mineralize organic P, or enhance symbiosis with native microbes. High PAE allows for use of accumulated soil P as opposed to relying on fertilizer application to meet crop demand.