Molecular and genetic basis of plant macronutrient use efficiency: Concepts, opportunities, and challenges

Interaction of both environmental and plant intrinsic factors determine the efficiency by which plants use nutrients to produce biomass and/or grain. Use efficiency of phosphorus, nitrogen and potassium, as the major macronutrients limiting plant growth, has a direct impact on global food production and fertilizer consumption, therefore, research on this topic is of especial interest for crop improvement because of its impact in world food security. The development of more efficient and precise techniques and strategies is providing exciting opportunities for the detailed study of the molecular and genetic components contributing to macronutrient use efficiency and, therefore, expanding our understanding on plant nutrition. The integration of available acknowledge and future experimentation, with model plants and crops, under both laboratory and field conditions will facilitate the design of more effective strategies to improve nutrient use efficiency in major crop species. The challenge is to make possible not only the optimum use of nutrients applied as fertilizers together with those already present in the soil, but converting marginal soils into productive arable land. In this chapter, we provide some basic concepts regarding macronutrients (especially phosphorus, nitrogen, and potassium) acquisition and utilization efficiencies, and review current knowledge on key genes regulating these processes in model plants and crops.