Fig. 4: PpRopGAPs and PpREN redundantly regulate tip growth and development.

a Colony growth of wild-type (WT) and mutant mosses. Scale bars: 0.5 cm. b Gametophores of WT, mutant, and rescued mosses. Cerulean-fusion PpREN or PpRopGAP1 (simplified as + REN and + GAP1) were expressed for rescue in the ropgap, ren septuple mutant background. Scar bar: 1 mm. c Cell morphology and growth of WT, mutant, and rescued mosses. Scale bar: 1 mm. d Tip cell growth in WT and mutant mosses. Representative kymographs of growing tip cells are shown (right). Note that cells in the ropgap, ren mutant are wavy. Scale bars: horizontal, 50 µm; vertical, 5 h. e Quantification of cell length in WT, mutant, and rescued mosses. f Quantification of growth rate in WT and mutant tip cells. g Localization of PpREN in the cytoplasm. Note that PpREN occasionally forms puncta-like structures but does not exhibit obvious enrichment or colocalization with FM4-64-labeled vesicles at the tip. Scale bars: 10 µm. h Summary of localization and rescue capability of full-length (FL) and mutant forms of PpRopGAP1. Note that PpRopGAP1 can partially rescue cell growth phenotypes in the absence of the Nter portion or a fully functional CRIB domain. The rescue capability was categorized as either complete (++), partial (+), or absent (−) when mosses exhibited fully, partially, or no elongated caulonema cells on BCDAT plates, respectively. Protein localization was determined by assessing the relative intensity on the membrane (Mem.) and in the cytosol (Cyto.). If the membrane signals were visually stronger than the cytosolic fluorescence, they were classified as membrane localization. Data are presented as box-and-whisker plots, showing the interquartile range (box), the median (horizontal line), and minimum and maximum values (whiskers) in (e, f). The number of cells used for quantification in (e, f) is shown at the bottom. Statistical analyses were performed using one-way ANOVA tests. ns, not significant. ****p < 0.0001. The exact p-values are available in Source Data. Similar results in (g) were obtained in three independent experiments. Source data are provided as a Source Data file.