Transcriptomic dynamics of petal development in the one-day flower species, Japanese morning glory (Ipomoea nil)

Abstract

Various aspects of Japanese morning glory (Ipomoea nil) petals, such as color, pattern, shape, flower opening time, and senescence, have been extensively studied. To facilitate such studies, transcriptome data were collected from flower petals at 3-h intervals over 3.5 days; the data was collected from 72 h before and 12 h after flower opening, accounting for 29 timepoints. Data analysis revealed substantial transcriptomic changes before and after flower opening. The expression patterns of cell division marker genes indicated that cell division practically stops at approximately 48 h before flower opening. Furthermore, the increased expression of genes encoding transporters for sugars, amino acids, nucleic acids, and autophagy-related genes was observed after flower opening, indicating the translocation of nutrients from senescing petal cells to other developing tissues. Correlations were found between the temporal expression patterns of the three transcriptional regulators and expression patterns of different sets of structural genes within the anthocyanin biosynthesis pathway, indicating differential reliance on each regulator for the activation of specific structural genes. Furthermore, clock genes were identified. Three copies of the clock gene ELF3 did not exhibit circadian rhythms, potentially allowing I. nil to adapt to high-latitude regions. The temporal transcriptome data and interactive database (https://ipomoeanil.nibb.ac.jp/fpkm/) offer valuable insights into gene expression dynamics, periodicity, and correlations and provide a crucial resource for further research on I. nil and other plant species.