Cold stress impairs nitrogen uptake and enhances translocation through AMT1 and NRT2 gene regulation in tomato

Nitrogen is a vital nutrient for plant growth, playing a crucial role in various physiological processes. Cold stress significantly impacts plant physiology, including nitrogen uptake and translocation. This study investigates the effects of cold stress on nitrogen dynamics in tomato plants by examining the expression of ammonium (AMT1) and nitrate (NRT2) transporter genes. Under normal conditions, AMT1 and NRT2 genes are predominantly expressed in the roots, with varying levels of expression in other tissues. However, following exposure to cold stress, a significant downregulation of most AMT1 and NRT2 genes in the roots was observed, indicating a reduced capacity for nitrogen uptake and assimilation. Conversely, there was a notable upregulation of these genes in the leaves, suggesting an enhanced capacity for nitrogen translocation and metabolism under cold conditions. This differential expression between roots and leaves highlights the plant's adaptive mechanisms to cope with environmental stress. It indicates a strategy to conserve energy in the roots while increasing nutrient transport in the leaves to support metabolic adjustments. These insights into the molecular basis of nitrogen management under cold stress can inform strategies to enhance crop resilience and productivity.