Genome-wide analysis of AP2/ERF genes in sweet cherry and functional characteristic of PavERF45 in response to cold stress

Sweet cherry (Prunus avium) contains abundant nutrients and is highly favored by consumers. However, cold stress severely limits its growth and development. Transcription factor AP2/ERF plays a crucial role in plant responses to abiotic stress. In this study, a total of 126 PavERF genes were identified in sweet cherry, and their gene structures, conserved motifs were analyzed using TBtools-II software. 23 collinearity events occurred within the PavERF gene members of sweet cherry, and 102 collinearity events were found between sweet cherry and Arabidopsis. Cis-element analysis indicated that AP2/ERF contained a variety of hormone- and stress-responsive elements. qRT-PCR analysis showed that PavERF responded to low-temperature stress to varying degrees, with PavERF45 being the most significantly upregulated. Transient overexpression of PavERF45 was achieved in transgenic tobacco via Agrobacterium-mediated genetic transformation, and its function was verified under cold stress. Under cold stress, tobacco plants overexpressing PavERF45 had lower relative conductivity (REC) than wild type (WT), while chlorophyll (Chl) content and SPAD value were higher than those of WT. Lower reactive oxygen (ROS) accumulation and higher ROS scavenger enzyme activities were noticed in OE-PavERF45 plants. This study provides insights into the functional roles of AP2/ERF in the cold stress response of sweet cherry.