Harnessing the new emerging imaging technologies to uncover the role of Ca2+ signaling in plant nutrient homeostasis

Increasing crop yields by using eco-friendly practices is of high priority to tackle problems regarding food security and malnutrition worldwide. A sustainable crop production requires a limited use of fertilizer as well as the employment of plant varieties with improved ability to acquire nutrients form soil. To reach these goals, the scientific community aims to understand plant nutrients homeostasis by deciphering the nutrient sensing and signaling mechanisms of plants. Several lines of evidence about the involvement of Ca2+ as the signal of an impaired nutrient availability have been reported. Ca2+ signaling is a tightly regulated process which requires specific protein toolkits to perceive external stimuli and to induce the specific responses in the plant needed to survive. Here we summarize both older and recent findings concerning the involvement of Ca2+ signaling in the homeostasis of nutrients. In this review we present new emerging technologies, based on the use of genetically encoded Ca2+ sensors and advanced microscopy, that offer the chance to perform in planta analyses of Ca2+ dynamics at cellular resolution. The harnessing of these technologies with different genetic backgrounds and subjected to different nutritional stresses will provide important insights to the still little-known mechanisms of nutrient sensing in plants.