Genome-Wide Identification of the AP2/ERF Gene Family and Functional Analysis of PgAP2/ERF187 Under Cold Stress in Panax ginseng C. A. Meyer

Panax ginseng C. A. Meyer (P. ginseng) is a medicinal plant rich in bioactive components such as ginsenosides, polysaccharides, and volatile oils and is widely used in both the pharmaceutical and food industries. While the AP2/ERF gene family is well-documented to play crucial roles in plant growth, development, and defense responses, functional studies on this gene family in P. ginseng remain unreported. Our genome-wide analysis identified 318 PgAP2/ERF family members, which are classified into five subfamilies: AP2, DREB, ERF, RAV, and Soloist. Homology analysis revealed that segmental duplication serves as the primary evolutionary driver for the PgAP2/ERF gene family in P. ginseng. RT-qPCR analysis demonstrated that all PgAP2/ERF members in the DREB-A1 subgroup respond to cold stress. Specifically, we found that the DREB-A1 member PgAP2/ERF187 plays a pivotal role in the cold stress response, with its expression specifically induced by ABA. Overexpression of PgAP2/ERF187 in Arabidopsis significantly enhanced the expression of cold tolerance-related genes. Subcellular localization analysis confirmed the co-localization of PgABF and PgAP2/ERF187 in the nucleus. Combining transcription factor interaction predictions and yeast one-hybrid experiments, we propose that PgABF likely regulates PgAP2/ERF187 expression by directly binding to its promoter region. These findings unveil the potential mechanism of the “PgABF-PgAP2/ERF187” regulatory module within the ABA signaling pathway during P. ginseng’s cold stress adaptation, thereby providing novel theoretical insights into the molecular mechanisms underlying P. ginseng’s cold resistance.