The study looked at how citrus plants use nitrogen to grow. By analyzing a database of citrus genes, researchers found key genes involved in nitrogen metabolism. These genes help the plant make important molecules like amino acids and nucleotides. Enzymes like nitrate reductase and glutamine synthetase play a big role in this process. The study showed that these genes are similar in different citrus species. This research can help scientists understand how these enzymes work in citrus plants.