Overexpressing mannose-binding Lectin (NTL) protein affects sugarcane physiological status and increase its resistance to aphids (Ceratovacuna langigera).

Narcissus tazetta Lectin (NTL) is a mannose-binding protein, known for its resistance to aphid (Ceratovacuna langigera). However, the mechanism underlying NTL-enhanced plant resistance to aphid remains elusive. Here, we produced NTL-overexpressing (NTL-OE) sugarcane lines that showed strong resistance to aphid. Overexpression of NTL gene led to reduction of total soluble sugar content, sucrose content, fructose content, soluble protein content, and most amino acid levels in sugarcane sap. Transcriptomic analysis and pathway annotation revealed significant role of plant hormone signal transduction, amino acid metabolism, photosynthesis-related pathways, and carbohydrate metabolism. Association analysis of the transcriptome and microbiome of NTL-OE sugarcane fed aphids showed the significance of Christensenellaceae family in sugar-related metabolic regulation and Buchnera in amino acid-related metabolic regulation, which corroborated the essential role of sugars and amino acids in aphid survival. Correlation analysis between NTL-OE sugarcane and aphid transcriptome discovered gene modules related to plant hormone signaling, amino acid metabolism, photosynthesis-related pathways, and sugar metabolism. Taken together, sugars and amino acids that were impacted by NTL protein overexpression in sugarcane sap were suggested to be critical for fed aphids' survival. Notably, HSP70 gene was up-regulated in both NTL-OE sugarcane and fed aphids that requires further investigation. This study suggested the role of NTL protein in plant resistance to aphids, offering new insights for mechanisms underlying NTL-enhanced plant resistance.