Decoding Plant Metabolomic Response to Potassium and Nutrient Stresses in Controlled Environments

Potassium (K) is an essential macronutrient, affecting numerous physiological, biochemical, and metabolic functions in plants. In protected cropping systems (PCS), which are controlled environments for intensive agriculture, optimizing K management is essential for attaining sustainable productivity and resilience under stressful growth conditions. Understanding plant responses to these conditions requires advanced analytical approaches, and metabolomics is emerging as a key tool, though there is still a lack of PCS-focused metabolomic studies. This review synthesizes the recent knowledge on plant metabolomic responses to K as a nutrient, emphasizing the central role of metabolomics in uncovering intricate biochemical pathways associated with K uptake, transport, and utilization. We investigate essential metabolic alterations in response to K deficiency, encompassing modifications in glucose metabolism, antioxidant synthesis, osmolyte accumulation, and hormonal regulation. The review also explores the relationships between potassium and other nutrients, specifically nitrogen, phosphorus, and essential micronutrients, and their impact on total plant metabolic networks. Furthermore, we discuss cutting-edge omics integration, precision fertigation, real-time sensor technologies, and machine learning applications that together promise to transform K fertilizer management in PCS. Future directions highlight the advancement of K-efficient cultivars, integrating metabolomic biomarkers in breeding, and overcoming challenges in data interpretation, scalability, and the high cost of metabolomic analyses and phenotyping technologies. Collectively, these insights provide a framework for improving crop health, production, and nutrient utilization efficiency for a more sustainable future in protected cropping.