Physiological and transcriptomic dissection of submergence tolerance in cabbage highlights ERF-VII and N-degron regulation

Climate change-driven flooding threatens cabbage ( Brassica oleracea var. capitata ) cultivation, yet the mechanisms underlying its submergence tolerance remain poorly understood. Here, we present an integrative analysis combining physiological measurements and time-course transcriptome profiling on cabbage cultivars with contrasting submergence tolerance, aiming to identify candidate regulatory modules potentially unique to Brassica submergence responses. The submergence-tolerant cultivar ‘Fuyudori’ demonstrated superior growth performance, antioxidative capacity, and a higher induction of glycolytic genes compared to the submergence-sensitive cultivar ‘228’. Consistently, transcriptome profiling revealed distinct transcriptional patterns between ‘Fuyudori’ and ‘228’ under submergence, particularly in genes related to translation and transcriptional regulation, suggesting their involvement in mediating submergence tolerance. Furthermore, ten cabbage homologs of group VII ethylene response factors (ERF-VIIs) harboring characteristic ERF domains and conserved N-terminal motifs were identified, among which BoERF71 and BoRAP2.12 were confirmed as substrates of the N-degron pathway. In ‘Fuyudori’, these ERF-VII genes displayed higher transcript levels and greater hypoxia-induced protein accumulation, enabling stronger activation of hypoxia-responsive genes such as BoADH1 and BoSUS1L . Our results suggest that elevated expression and stronger hypoxia-induced accumulation of BoERF-VIIs are associated with enhanced submergence tolerance. This work provides the first detailed molecular insight into cabbage submergence responses and lays a foundation for breeding submergence-tolerant Brassica crops. • Contrasting cabbage cultivars serve as a model to dissect submergence tolerance. • A phenotyping-biochemical toolkit enables evaluation of submergence tolerance. • Tolerant cultivar shows stronger glycolysis, antioxidant, and regulatory capacity. • BoERF71 and BoRAP2.12 are identified as N-degron pathway substrates. • Elevated BoERF-VII expression and hypoxia-induced abundance drive gene activation.