The 9-cis-epoxy carotenoid dioxygenase (NCED) is an enzyme that is crucial in abscisic acid (ABA) biosynthesis, and its role is vital in plant development and abiotic stress. However, the function of the NCED family in Rosaceae plant species remains unclear. Through genome-wide screening, we identified 10, 10, 11, 12 and 13 NCED genes in Prunus mume, Prunus apricot, Prunus salicina, Prunus persica, and Rosa chinensis, respectively. Phylogenetic analysis showed that these NCED genes were divided into six groups. Gene structure analysis showed that the number and size of introns were relatively constant in each subfamily, while the motif composition differed significantly among them. Collinearity analysis revealed a high homology of NCEDs in the Prunus genus. Promoter cis-acting element analysis showed that eight PmNCEDs contained abscisic acid-responsive elements (ABRE). Furthermore, expression profile analysis based on qRT-PCR revealed that PmNCED3, PmNCED8 and PmNCED9 were up-regulated in response to low temperature stress, suggesting their significant role in the plant’s response to cold stress. These findings provide insights into the structure and evolution of PmNCEDs and lay the foundation for further studies regarding their function during cold stress.

Gibberellins (GAs), enzymes that play a significant role in plant growth and development, and their levels in plants could be regulated by gibberellin-oxidases (GAoxs). As important fruit trees and ornamental plants, the study of the mechanism of plant architecture formation of the Prunus genus is crucial. Here, 85 GAox genes were identified from P. mume, P. armeniaca, P. salicina, and P. persica, and they were classified into six subgroups. Conserved motif and gene structure analysis showed that GAoxs were conserved in the four Prunus species. Collinearity analysis revealed two fragment replication events of PmGAoxs in the P. mume genome. Promoter cis-elements analysis revealed 24 PmGAoxs contained hormone-responsive elements and development regulatory elements. The expression profile indicated that PmGAoxs have tissue expression specificity, and GA levels during the dormancy stage of flower buds were controlled by certain PmGAoxs. After being treated with IAA or GA₃, the transcription level of PmGA2ox8 in stems was significantly increased and showed a differential expression level between upright and weeping stems. GUS activity driven by PmGA2ox8 promoter was detected in roots, stems, leaves, and flower organs of Arabidopsis. PmGA2ox8 overexpression in Arabidopsis leads to dwarfing phenotype, increased number of rosette leaves but decreased leaf area, and delayed flowering. Our results showed that GAoxs were conserved in Prunus species, and PmGA2ox8 played an essential role in regulating plant height.