The dynamic change of flower color is a key trait for plant environmental adaptation and pollinator attraction, yet its spatiotemporal regulatory mechanisms remain poorly understood. Hibiscus mutabilis L., known for its remarkable diurnal color-changing phenomenon, provides an ideal model for deciphering the dynamic regulation of flower color. This study integrated metabolomics, transcriptomics, and epiphytic microbial community analyzes to systematically compare the spatiotemporal differences between petals and the flower base of H. mutabilis . Metabolomic analysis revealed that differential metabolites between petals and the flower base were primarily enriched in pathways such as glycolysis and glutathione metabolism. Differences between morning and afternoon in the flower base were concentrated in flavonoid biosynthesis and amino acid metabolism pathways. Transcriptomic analysis identified MYB114-like was significantly upregulated in the afternoon, with its expression co-enriched with genes from the plant hormone signaling and MAPK pathways, suggesting it participates in the regulatory mechanism of environmental signal responses. Microbial community analysis showed a significant increase in the relative abundance of Actinomycetota in the flower base from morning to afternoon. Functional prediction suggested that these microbes might be involved in processes such as redox metabolism and nucleotide degradation. This study reveals a multidimensional regulatory network involving metabolism, transcription, and microbes governing the dynamic color change in H. mutabilis , from the perspective of spatial heterogeneity and plant-microbe interactions, providing novel insights into the mechanisms of flower color formation and the adaptability of ornamental plants.
Tang et al. (Thu,) studied this question.