Role of Kinases for Regulating K + Homeostasis Under Salt and Drought Stress Conditions

Plants experience one or more abiotic stresses, like high light, temperature, cold, drought and salinity during the entire course of their life-cycle. The mechanism of stress sensing and activation of suitable response is guided by sequential and highly regulated reactions termed as "signal transduction." In stress related signal transduction, kinases play a very crucial role. Among several known mechanisms, kinase mediated regulation of potassium (K+) homeostasis has been studied in detail at functional genomics level. K+ is an important macronutrient for plant growth and development and it plays a crucial role in processes like protein synthesis, enzyme activation, stomatal regulation, seed germination and emergence, water uptake, nutrient balance, reproductive development and photosynthesis. Besides, it is also an important regulator of plant defense system which includes modulation of ROS levels, aquaporin activity, osmotic adjustment and osmolyte accumulation. Hence, coordinated K+ response is considered crucial for plant performance under stress conditions. The present chapter provides a comprehensive overview of various kinases for regulating K+ response in plants, especially under salt and drought stress conditions. The role of different kinase families is also integrated to explain their interrelationship at cellular level.