Elevated CO2 and Its Impact on Nitrogen and Phosphorus Dynamics in Field Crops

Abstract

Elevated CO2 from human activities is altering global climate and affecting agriculture, particularly cereals and millets, which supply 60% of global food. Increased CO2 disrupts Nitrogen and Phosphorus absorption, impacting plant growth and photosynthesis. To cope, plants adjust root architecture, enhance mycorrhizal associations, and activate metabolic and transcriptional responses. These adaptations help mitigate nutrient deficiencies. Root hairs play a crucial role in anchoring plants to the soil and enhancing nutrient uptake by increasing root surface area. Their development, controlled by factors like phytohormones, pH, and cytoskeleton dynamics, involves initiation and tip growth. Plants also rely on arbuscular mycorrhizal fungi (AMF) to acquire nitrogen (NH4⁺ and NO3⁻) and phosphorus through specialized structures called arbuscules. This pathway becomes increasingly important under elevated CO2 (eCO2), which inhibits NO3⁻ assimilation in leaves. Under eCO2, plants adjust their nitrogen status through NRT1 and NRT2 transporters and coordinate carbon and nitrogen metabolism via transcription factors like HY5. Prolonged eCO2 exposure often leads to phosphorus deficiency, prompting plants to excrete organic acids and employ alternative metabolic pathways to maintain homeostasis. Sustainable practices such as legume intercropping, no-till farming, and CRISPR-based genome editing hold promise for mitigating nutrient deficiencies. Millets, with their nutrient efficiency and resilience under eCO2, emerge as ideal crops for sustainable agriculture. By adopting innovation and sustainable approaches, it is possible to counter nutrient loss and ensure food security amidst climate change.