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Abstract

Jasmonic acid (JA) is an endogenous plant hormone that plays a critical role in plant growth and physiological processes. In this study, we analyzed the dynamic changes in JA and its derivatives metabolism, membrane lipid degradation, carbon metabolism, and antioxidant capacity in postharvest Toona sinensis buds stored at different temperatures (4°C and 20°C). At 20°C, rapid activation of JA biosynthesis genes triggered accumulation of JA and jasmonoyl-isoleucine (JA-Ile) within 1 h, initiating a positive feedback loop that amplified defense signaling. Sustained pyruvate kinase (PK) activity directed carbon flow toward glycolysis to support JA synthesis, while elevated phosphoenolpyruvate carboxykinase (PEPCK) accelerated nutrient consumption quality deterioration of toon buds. In contrast, at 4°C, suppressed expression of membrane lipid metabolism-related phospholipase genes (PLA1-1, PLD-1), JA synthesis-related genes including allene oxide synthase (AOS), allene oxide cyclase , OPDA reductase 3 (OPR3), and lipoxygenases (LOX), together with delayed LOX activation, limited JA flux. The reduced expression of PLA1-1 and PLD-1 further contributed to the maintenance of membrane integrity. Methyl jasmonate (MeJA) accumulated as a signaling reservoir. High hexokinase activity coupled with low PK activity redirected carbon flow toward the pentose phosphate pathway, supporting sustained increase in total antioxidant capacity (T-AOC). These findings elucidate the JA-mediated physiological mechanisms underlying postharvest storage of T. sinensis at different temperatures and provide a theoretical basis for optimizing postharvest storage strategies in horticultural species.

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