Plant nutrient stress adaptation: A prospect for fertilizer limited agriculture

Nutrients are essential for optimal growth and development of plants. Nutrient availability and composition in the soil varies largely from region to region. The deficiency of essential nutrients may cause chlorosis, necrosis and stunted growth that eventually cause significant crop loss and in turn, affects human nutrition. Usage of chemical fertilizers to enrich soil mineral nutrient status is a normal practice in modern agriculture. The massive application of fertilizers improved crop yield but it became major environmental concern as it causes eutrophication and loss of soil fertility. This overdependence on fertilizers can be minimized by exploring the nutrient deficiency-induced adaptations in plants and could be used as a potential strategy to develop nutrient deficiency-tolerant varieties. Plants undergo morphological, biochemical, and rhizosphere-mediated modifications to improve nutrient absorption under nutrient deficiency. Morphological changes are implemented at the shoot, root, and leaf levels. Plants limit shoot branching and promote leaf senescence in nutrient-deficient plants. Plants can modify root architecture by inhibiting primary root growth and promoting lateral root and root hair growth to explore more soil zones to find the limited nutrients. Plants can form symbiotic associations with fungi and bacteria to enhance nutrient uptake. For ensuring efficient nutrient absorption, plants also upregulate the expression of nutrient transporters, enhance the release of acid phosphatases, promote proton extrusion and secrete organic acids. Anthocyanin accumulation and ROS release were also observed in plants grown in nutrient-deficient soil. In this article, we discuss the different nutrient deficiency-induced adaptations of plants and discuss the most feasible adaptive mechanisms to explore the generation of crops with enhanced nutrient stress resilience.