Integrating multiomic resources and gene expression studies to identify candidates for engineering climate-resilient Brassica
Climate-related stresses, including drought, salinity, temperature extremes (cold and heat), and waterlogging, substantially constrain Brassica napus productivity, particularly when they occur during reproductive development or as compound stresses. Because B. napus is an allotetraploid species, stress-resilience traits are shaped by polygenic inheritance, gene redundancy, and subgenome-specific regulation. This review integrates QTL mapping, GWAS, transcriptomic evidence, and functional studies to prioritize candidate genes and pathway-level modules associated with climate-resilience. Drought and salinity candidates converge on ABA signaling, osmotic adjustment, proline biosynthesis, aquaporin-mediated water transport, and ion-homeostasis pathways, including SOS and NHX-related components. Temperature resilience is associated with CBF/DREB-mediated cold acclimation and HSF-HSP-DREB2A-linked proteostasis under heat stress. Waterlogging tolerance is linked to hypoxia and ethylene signaling, redox protection, and CIPK15/SnRK1-related energy regulation. We distinguish positional candidates from expression-supported and experimentally validated genes and discuss how these targets can be used in MAS, genomic selection, allele pyramiding, and genome editing. Current evidence supports pathway-level convergence, but causal validation of individual B. napus gene copies and evaluation of yield trade-offs remain major priorities.