Multiomics analysis reveals a gene regulatory network at the intersection of multiple pathways during the late stage of pear flower development

Over their evolution, plants have developed complex and precise mechanisms to regulate flowering, utilizing both internal factors within the plants themselves and external factors in the environment. Moreover, pathways such as those regulating plant stem cells, hormones, and volatile compound synthesis and metabolism are all involved in controlling flowering. However, to date, few comprehensive analyses of the core pathways involved in the flowering process have been reported. In this study, the volatile compound and hormone contents in pear blossoms at seven post-physiological differentiation stages (i.e., in the late stage of flower development) were assessed. The total volatile compound content varied greatly, ranging from 77.8 to 442.8 ng/g, and were mainly divided into seven main categories: alcohols, alkanes, ketones, terpenoids, aromatic hydrocarbons, esters, and aldehydes. The contents of the different types of compounds varied significantly. The content of gibberellin (GA) gradually decreased during pear blossom development and was significantly positively correlated with the flower volatile aldehyde and aromatic contents. Exogenous treatment with a 20 mg/L GA solution promoted flowering, whereas treatment with a 50 mg/L GA solution inhibited flowering. In addition, GA treatment changed the composition of volatile compounds, with significantly higher total and aldehyde contents than in the control group. By further integrating transcriptomics, hormonomics, and HS-SPME–GC–MS metabolomics, we identified 466 key genes involved in the pear blossom development process, including 13 core genes. This study provides profile of the pear flowering process at the gene transcript level, as well as hormone and volatile metabolism profiles for the pear flowering process, and lays a foundation for further analysis of the molecular and genetic mechanisms of pear flowering.