Abstract
BACKGROUND: The AP2/ERF is one of the largest gene families in plants, which plays an important role in plant growth and development and resistance to stresses. However, the quantity, evolutionary characteristics and expression characteristics in different tissues of this gene family in Rosa roxburghii are still unknown. RESULTS: In this study, 106 members of the AP2/ERF gene family were identified in the genome of Rosa roxburghii. These members are unevenly distributed on seven chromosomes, and most of them are predicted to be located in the nucleus. Phylogenetic analysis reveals that all the family members are classified into four subfamilies, DREB, ERF, AP2 and RAV with their numbers being 31, 57, 14 and 4 respectively. Analysis of cis-acting elements, conserved motifs, and gene structure shows that a large number of cis-acting elements related to hormones and stress are found. Furthermore, the conserved motif 1 is present in all family members, and except for the RAV subfamily, each subfamily contains unique motifs. However, the gene structure of AP2 subfamily is obviously different from the other three subfamilies, which contains more specific motifs and cds. Segmental duplication and synteny analysis reveal that the number of AP2/ERF varies greatly among Rosaceae, and segmental duplication is one of the important factors for the expansion of the AP2/ERF family in Rosa roxburghii. Furthermore, based on transcriptome data and RT-qPCR, the specific expression characteristics of AP2/ERF genes and their alternative splicing in eight different tissues of Rosa roxburghii were presented and verified. CONCLUSIONS: In conclusion, this study comprehensively identified and analyzed the classification, evolution, and expression characteristics of the AP2/ERF family genes in Rosa roxburghii, and provided a reference for further molecular breeding of Rosa roxburghii.