Molecular Module FcERF71-FcDREB1 of Fig Represses Fruit Softening via FcPL7 and FcPG12

Fruit firmness is a key quality trait affecting marketability, yet the regulatory mechanisms underlying softening remain poorly understood. In fig (Ficus carica L.), we identified an AP2/ERF transcription factor, FcDREB1, as a repressor of fruit softening. FcDREB1 binds directly to the promoters of the key softening-related genes pectate lyase 7 (FcPL7) and polygalacturonase 12 (FcPG12) to suppress their expression and reduce PL and PG activity. Furthermore, we discovered FcERF71, an ethylene-induced AP2/ERF protein, which interacts physically with FcDREB1 and weakens the latter's trans-repression effect on FcPL7 and FcPG12. Notably, FcERF71 also directly inhibits FcDREB1 transcription. This intricate interplay between FcERF71 and FcDREB1 reveals a dynamic regulatory module for balancing key cell-wall-modifying enzymes during fig fruit ripening. Our findings elucidate the complex regulatory network governing fig fruit softening, paving the way for targeted genetic strategies to improve the storability.