Phospholipid remodeling during maturation and cold storage modulates maturity-dependent chilling tolerance in mango

Mango fruit is susceptible to chilling injury (CI) at temperatures below 13 °C. Although CI tolerance in mangoes has been reported to increase with fruit maturation, the underlying mechanisms remain unclear. This study investigated the contribution of membrane phospholipid (PL) composition and its regulation to maturity-dependent chilling tolerance in ‘Irwin’ mangoes. CI symptoms developed in mature green (MG) fruit but not in tree-ripe fruit after storage at 5 °C. At harvest, tree-ripe fruit exhibited a higher phosphatidylcholine (PC)/ phosphatidylethanolamine (PE) ratio and a lower degree of PL unsaturation compared with MG fruit. Under 5 °C conditions, the PC/PE ratio remained stable in both tree-ripe and MG fruit, with tree-ripe fruit consistently maintaining the higher ratio than MG. Additionally, both fruit types enhanced PC unsaturation to comparable levels, while PE unsaturation remained largely unchanged, with tree-ripe fruit consistently retaining lower PE unsaturation than MG fruit throughout the chilling period. At the transcriptional level, tree-ripe fruit induced the expression of fatty acid desaturase 2 during cold storage, whereas MG fruit upregulated phospholipase genes during the rewarming phase. These findings indicated that cold-induced PC desaturation was a universal response to chilling in both MG and tree-ripe fruit, while the superior chilling tolerance in tree-ripe fruit was primarily attributed to the higher PC/PE ratio and lower PE unsaturation level established during pre-harvest maturation. This study provides novel mechanistic insight into how PL remodeling during maturation and chilling storage modulates maturity-dependent chilling tolerance in mango.