Responses of sugar metabolism to nitrogen fertilization in Lonicera caerulea: insights from integrated targeted...

This study assessed 26 varieties of Lonicera caerulea, which exhibited significant genetic variation in sugar and acid profiles at the green fruit, veraison, and ripe stages. Nitrogen treatment in high-sugar cultivars led to a notable reduction in fructose and glucose concentrations. The sugar content differences between high- and low-sugar cultivars were primarily attributed to variations in fructose and glucose levels. At maturity, glucose and fructose concentrations ranged from 58.0 to 135.7 mg/g and 43.5 to 115.8 mg/g, respectively, reflecting genetic differences prior to nitrogen treatments. Integrated transcriptomic and metabolomic analyses revealed key gene modules associated with sugar metabolism. Molecular docking showed strong binding between fructose-1,6-bisphosphate and fructose-bisphosphate aldolase (-7.95 kcal/mol), as well as a biologically relevant but weak interaction between oxaloacetate and phosphoenolpyruvate carboxykinase (-4.0 kcal/mol). These findings offer valuable molecular understanding of the control of sugar metabolism in blue honeysuckle, offering insights into improving fruit quality and functional food.