Identification of differentially expressed genes during bud dormancy release in Paeonia lactiflora ‘Dafugui’

Herbaceous peony is a popular floricultural crop, and Paeonia lactiflora LSQUODafuguiRSQUO is the most frequently used cultivar in China in both research and practical forcing cultivation of herbaceous peony. This study was performed to explore the molecular mechanisms that underlie bud dormancy release in P. lactiflora LSQUODafuguiRSQUO. Three phases of peony bud samples were investigated for comparative transcriptomic analysis: endodormant buds (S1), endodormancy-released buds subjected to artificial chilling (S2) and ecodormancy-released buds under natural conditions (S3). The results showed that 1772 differentially expressed genes (DEGs) from the S1 vs. S2 comparison sets and 3119 DEGs from S2 vs. S3 were detected according to a threshold false discovery rate of KLEINERDAN0.01 and a fold change of ≥2. Among these DEGs, 88.5 and 85.0% respectively, were successfully annotated. In the light of the gene ontology (GO) classification for both transitions, the most abundant DEGs from the biological process, cellular component and molecular function categories were related to metabolic processes, cell parts and catalytic activity, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the plant hormone signal transduction, DNA replication and flavonoid biosynthesis pathways were significant for both transitions and that the photosynthesis pathway was significant only for the second transition. The DEGs encoding receptors and effectors in the abscisic acid (ABA), gibberellic acid (GA) and auxin-responsive protein IAA (IAA) signaling pathways are further discussed. Our comprehensive transcriptomic analysis enriches molecular information for further elucidation of the mechanism underlying bud dormancy release in herbaceous peony.