Plant Protein Phosphatase 2C: Critical Negative Regulator of ABA Signaling

Abstract

Plants are sessile organisms on earth; hence, they are affected by adverse conditions in terms of growth and development. Plants have evolved with complex sensing and signaling machinery to combat these abiotic and biotic stresses. ABA is a classical phytohormone for growth and development, which regulates the adaptive responses of plants to various abiotic stresses. During the last 30 years, ABA signaling has emerged as a major abiotic stress signaling in plants. ABA signaling is majorly composed of three core components: ABA receptor, protein kinases, and protein phosphatases. Protein phosphatase 2Cs, also known as ABA co-receptors, function as a negative regulator of ABA signaling via interacting and inhibiting the kinase activity of the positive regulator SnRK2s. Besides this, protein phosphatase 2Cs are also involved in development, nutrient deficiency, and biotic stress responses in plants. Here, in this chapter, we are presenting the understanding toward the role of protein phosphatase 2Cs in ABA and other stress signaling pathways, which could provide important insight to develop methods to improve the stress tolerance of crop plants.