Oxidative Stress Under Macronutrient Deficiency in Plants

Mineral nutrients play crucial functions in the growth and development of plants as they are intimately involved in the plant cell organization and metabolic functions. The mineral nutrients are either structural/functional constituents of enzymes or act as activators or regulators of various enzyme activities. The macronutrients like N (nitrogen) and P (phosphorus) form structural constituents of building block materials, and some of them [K (potassium), Ca (calcium), and Mg (magnesium)] are regulator or activator of enzymes. Deficiencies of macronutrient affect various physiological or metabolic activities including increased production of reactive oxygen species (ROS) in the organisms. Excess production of ROS causes oxidative stress in the plants. To counter with the oxidative stress, plants have evolved both enzymatic and non-enzymatic ROS scavenging system for protection of cellular components against deleterious ROS. Antioxidant machinery is comprised of various antioxidant enzymes such as peroxidases (POD), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), and non-enzyme molecules such as ascorbate (AA), glutathione (GSH), carotenoids and alpha-tocopherols. Reactive oxygen species can attack cellular structures such as cell membranes and various biomolecules including proteins and nucleic acids and causes lipid peroxidation and protein damage. In this review, we summarize recent developments on oxidative stress and antioxidant responses of plants induced by macronutrient deficiency. Further, we discuss possible ROS signaling events involved in oxidative stress and antioxidant responses induced due to different macronutrient deficiency.