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 have been implicated in these events, yet the temporal expression patterns 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 during petal development were analyzed by co-expression network analysis to identify stage-specific expression patterns. This revealed that InXTH genes fall into distinct co-expression modules whose expression peaks at specific developmental stages. Specifically, two InXTH genes are preferentially expressed during the early cell-division phase, whereas five and one members are expressed immediately before and at flower opening, respectively. At these later stages, each module was characterized by a single dominant gene showing exceptionally high transcript accumulation, suggesting its close transcriptional coordination with the timing of flower opening. These findings describe the transcriptional dynamics of the InXTH family during petal development and provide a candidate framework for future functional studies of cell wall remodeling in flower opening.