Fig. 1: SYP72 is specifically expressed in the vegetative cell of mature pollen, and syp72 mutants display pollen germination defects.

a–d Analysis of pSYP72:H2B-GFP (a, c) and pSYP72:GFP-SYP72 (b, d) reporter lines reveals that SYP72 is specifically expressed in the male (a, b) but not the female gametophyte (c, d). GFP GFP fluorescence, Merge merged images for GFP and 4′,6-diamidino-2-phenylindole (DAPI) staining in a, b, and merged images for GFP and differential interference contrast (DIC) in c, d. Images of non-transgenic controls are shown in Supplementary Fig. 2. Nucleolus of microspore and bicellular pollen have weak auto-fluorescence, and auto-fluorescence was also observed in the pollen wall. MS microspore, BC bicellular pollen, TC tricellular pollen, n nucleus, nu nucleolus, gn generative nucleus, vn vegetative nucleus, sn sperm cell nucleus, pm plasma membrane, es embryo sac. Scale bars: 5 µm for pollen, 25 µm for ovule. e, f Mutation in SYP72 leads to a marked decrease in pollen germination. e Representative images of pollen germination from the Col-0 wild type (WT), the syp72-1 mutant, and the gSYP72 complementation line. Scale bars, 100 µm. f Pollen germination frequency in the WT, syp72-1, and the gSYP72 complementation line. Data represent the mean ± SD from four independent experiments, with 300 pollen grains each (n = 1200). g Statistical data of pollen tube length of the WT and the syp72-1 mutant at different hours after germination. Data for pollen tube length are presented in the box-and-whisker plots. The centreline in the plot represents the 50th percentile. The bottom and top of each box indicate 25th and 75th percentiles, and the whiskers represent the minimum and maximum values. (WT, n = 80 biologically independent samples; syp72-1, n = 70 biologically independent samples). h Representative images of siliques from the WT and the syp72-1 mutant. Arrows indicate aborted seeds. i Quantification of seed setting from the WT, the syp72-1 mutant, gSYP72, and GFP-SYP72 complementation lines. Data represent the mean ± SD from four independent quantifications, with five siliques each (n = 20). Asterisks indicate statistically significant differences (two-tailed Student’s t test, *P < 0.05; ***P < 0.001; ****P < 0.0001). Observation of GFP in pSYP72:H2B-GFP (a, c) and pSYP72:GFP-SYP72 (b, d) transgenic plants was repeated at least three times with similar results.