Phenylalanine-mediated reprogramming of lipid, pentose phosphate, and energy metabolism delays senescence in Rosa roxburghii fruit

Although phenylalanine can inhibit fruit senescence, its effects on <i>Rosa roxburghii</i> remain unknown. We hypothesized that it delays senescence by modulating fatty acid metabolism, maintaining energy homeostasis, and supporting pentose phosphate pathways. To test this, postharvest fruits were treated with phenylalanine and physiological and molecular changes were evaluated. Treatment reduced decay, O₂• - production, H₂O₂, and MDA, and slowed the decline in firmness, SSC, AsA, and GSH. It decreased saturated fatty acids while preserving unsaturated fatty acids by regulating activities and expression of lipid metabolism enzymes. In parallel, phenylalanine enhanced activities and expression of energy metabolism enzymes, maintaining higher ATP, ADP, and energy charge. Activities and expression of G6PDH, 6PGDH, and NADK were also increased, accompanied by higher NADP and NADPH levels and lower NAD and NADH levels. These findings support our hypothesis that phenylalanine delays senescence of <i>R. roxburghii</i> fruit and highlight its potential as a natural treatment to prolong postharvest storage life and maintain fruit quality.