Controlled atmosphere storage modulates the exocarp-color and mesocarp-softening synchronization in Hass avocado
Controlled atmosphere storage is a key postharvest technology for extending the commercial life of Hass avocado (Persea americana Mill.) during long distance transport. However, color-firmness desynchronization, where the mesocarp softens before the exocarp develops its characteristic black color, remains a major challenge. This study evaluated the combined effects of harvest maturity (middle and late) and storage conditions (regular air, RA; controlled atmosphere, CA) on exocarp color-mesocarp firmness synchronization in Hass avocado. Integrative transcriptomic and metabolomic analyses were performed on exocarp tissues collected after 30 days of storage and at the ready-to-eat (RTE) stage. Integrative multi-omics (DIABLO sPLS-DA) identified early candidate biomarkers of storage response, including WRKY22, INT2, SnRK2.10, and arabitol (CA markers), and TT7/CYP75B1, SUS4, myo-inositol, and sucrose (RA markers). At the RTE stage, SLP2, BOB1, and SULTR3;1 correlated with black coloration, whereas MAPKKK21, RPL24A, and IAA13 were associated with green phenotypes. Overall, CA storage maintained cellular homeostasis and promoted anthocyanin biosynthesis, leading to improved exocarp color mesocarp firmness synchronization. These findings provide molecular and metabolic insights into the mechanisms underlying ripening uniformity in Hass avocado and propose potential biomarkers for early postharvest prediction of the disorder.