Genome wide identification and co-expression analysis of the xyloglucan endotransglucosylase/hydrolase gene family in Japanese morning glory

Flower opening is a dynamic process involving cell proliferation and turgor-mediated petal cell expansion. The xyloglucan endotransglucosylase/hydrolase (XTH) family enzymes are essential for these events, yet the functional roles and temporal deployment of this diverse gene family in ephemeral-flowering plant Ipomoea nil remains uncharacterized. In this study, 36 XTHs were identified, and their physicochemical properties and subcellular localizations were predicted, alongside organ-specific expression profiles. Furthermore, time-course transcriptomic data were utilized to identify their specialized expression patterns through co-expression network analysis. This revealed that InXTH genes are organized into distinct modules synchronized with specific developmental stages. Specifically, two InXTH genes are highly active during the early cell-division phase, whereas five and one members are expressed immediately before and at flower opening, respectively. At these later stages, a single dominant isozyme exhibits exceptionally high transcript levels in each module, suggesting these dominant XTHs likely contribute to the cell wall remodeling required for anthesis. These findings provide fundamental insights into the temporal orchestration of cell wall-modifying enzymes and establish a molecular framework for understanding flower opening in dicots.