Genome-Wide Identification and Characterization of Q-Type C2H2 Zinc Finger Proteins in Rapeseed (Brassica napus L.) and Their Expression Patterns Across Tissues and Under Abiotic Stress

Q-type C2H2 zinc finger protein (ZFP) transcription factors, a plant-specific subfamily of C2H2 ZFP, have been implicated in regulating abiotic stress responses, growth, and developmental processes in plants. Rapeseed (Brassica napus L.) is a crucial oil crop widely used for the production of high-quality vegetable oil, animal feed, and biodiesel. Compared with studies on Q-type C2H2-ZFP genes in other plant species, systematic research has not been performed in B. napus. In this study, a comprehensive genome-wide analysis of Q-type C2H2-ZFPs in B. napus was conducted. A total of 216 Q-type C2H2-ZFP genes were identified, exhibiting extensive and uneven distribution across the 19 chromosomes. Phylogenetic analysis, based on homologs from Arabidopsis, classified these genes into eight distinct subfamilies, with each containing one to three conserved “QALGGH” motifs. Each subfamily exhibited similar motif compositions and gene structures. Evolutionary studies revealed that segmental duplication events played a crucial role in the expansion of the BnaQ-type C2H2-ZFP gene family. Expression pattern analysis in different tissues and under abiotic stress identified BnaA03g09250D, BnaC09g35160D, BnaC03g11570D, and BnaA10g25850D as candidate genes involved in the response to freezing stress. Overexpression of BnaC09g35160D provided preliminary evidence that it enhances freezing tolerance in plants. This comprehensive study of Q-type C2H2-ZFPs in B. napus will enhance our understanding of the BnaQ-type C2H2-ZFP gene family and provide valuable insights for further functional investigations of BnaC09g35160D.