Morphological, physiological, and transcriptomic insights into response the of Lycium barbarum L. (‘Ningqi No.1’) seedlings to low-nitrogen stress

Nitrogen is one of the essential elements for plant growth and development. In this study, we assessed the effects of low-nitrogen (LN) on Lycium barbarum L. seedlings, finding that LN stress caused a notable decrease in plant height, fresh and dry weights, and leaf nitrate nitrogen levels. LN stress also altered the activities of the antioxidant defense system, key enzymes involved in nitrogen assimilation, and phytohormone levels. Transcriptomic analysis identified 3015, 2032, and 3382 differentially expressed genes (DEGs) in roots, stems, and leaves, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis further highlighted the significant impact of LN stress on nitrogen metabolism, phenylpropanoid biosynthesis, flavonoid biosynthesis, and ascorbate and aldarate metabolism. These findings enhance our understanding of the molecular mechanisms governing the response of Lycium barbarum L. to LN stress and provide a theoretical basis for the targeted breeding of nitrogen-efficient wolfberry varieties.