Phosphate and zinc interaction in soil and plants: a reciprocal cross-talk

Phosphate (P) is a crucial nutrient serving ATP biosynthesis and activating enzymes in important signal transduction pathways. Zinc (Zn) is another important micronutrient that plays a structural role in enzymes and regulatory proteins. P and Zn might work synergistically in plant processes like root development, photosynthesis, and respiration. But P often interacts with other micronutrients such as Manganese (Mn), Iron (Fe), Copper (Cu), and Zinc (Zn), which can influence their absorption and accumulation. Among those interactions, P-Zn interaction is the most discussed as a high amount of P impedes Zn bioavailability and vice-versa. Though the influence of this interaction in plants is reflected only at morphological and physiological levels, it is imperative to consider their cross-talk at three different levels i.e., in soil, during plant uptake, and at the time of translocation to the aerial parts. In common agricultural practices, crop plants are force-fed with P fertilizers to maximize yield which hinders Zn availability. Incessant, indiscriminate, and repetitive application of P and Zn-based fertilizers also affects soil health. This review brings forth and discusses various levels of P-Zn interaction in plants and soil, highlighting the missing links that require further study or validation. The review also summarizes the different approaches that can be taken to mitigate P-Zn negative interaction to achieve better and sustainable crop productivity in the future.