Identification and expression analysis of AP2/ERF transcription factors (DREB and ERFs) involved in cold stress response in <i>Asparagus officinalis</i>

APETALA2/ethylene response factor (AP2/ERF) transcription factors have been identified in many plant species, and their subfamilies play crucial roles in the regulation of gene expression in response to cold stress. Molecular pathways of cold stress response, however, have not been studied in asparagus. Using two contrasting cultivars, the objective of this study was to evaluate C-repeat binding factor (CBF) gene expression in response to cold shock and cold acclimation treatments in 10-week-old asparagus seedlings grown under controlled environment conditions. Two dehydration-responsive element binding (DREB) genes ( DREB2C and DREB2B), identified as potential CBF candidates, were induced at high levels, especially in the ferns and rhizomes of both cultivars. Cold acclimation led to stronger and longer-lasting DREB expression compared to cold shock treatment. Three ERF genes were downregulated in both cultivars for the two treatments, suggesting negative regulation of cold stress response. Using the genes under study, no gene expression differences were observed between the two cultivars for either of the treatments. Further experimental validation is needed to determine whether DREB2C and DREB2B genes fully function as CBFs and if they share roles with stress-responsive DREB genes. Understanding cold response mechanisms in asparagus may facilitate strategies to enhance freezing tolerance of the crop.