Regulatory roles of ABF/AREB/ABI5 transcription factors in nutrient stress and hormonal signaling in oilseed rape

The balance between nutrients and hormones is critical for optimal plant growth and development, as imbalances can trigger severe physiological and developmental disorders. ABRE Binding Factors (ABFs), ABA-Responsive Element Binding Factors (AREBs), and ABA INSENSITIVE 5 (ABI5) are key regulators of stress-responsive gene expression, particularly under abiotic stresses. However, their roles in oilseed rape (Brassica napus L.) under nutrient stress and phytohormone regulation remain largely unexplored. In this study, we identified and characterized 30 putative ABFs/AREBs/ABI5s in the B. napus genome through phylogenetic and structural analysis, grouping them into five distinct clades. Sequence alignment revealed strong conservation among family members, and subcellular localization confirmed their nuclear presence. Expression profiling showed that many BnaABFs/AREBs/ABI5s genes respond dynamically to nutrient deprivation, salt stress, and exogenous phytohormone treatments (abscisic acid, gibberellic acid, and salicylic acid), with both up- and downregulation observed. Among them, BnaABF1-a, BnaABF3-c, and BnaABI5-b exhibited the most pronounced changes under nutrient and hormonal stress conditions. These findings provide valuable insights into the evolution, regulation, and functional potential of BnaABFs/AREBs/ABI5s genes in oilseed rape. By elucidating their roles in nutrient stress responses, this work lays the foundation for targeted functional studies and breeding strategies to develop nutrient-efficient, stress-resilient oilseed rape cultivars, contributing to sustainable agriculture and climate-resilient crop improvement. improvement.