Fig. 5: Late arrival of phragmoplast POK2 Δ#4 population to the cortex.

a Domain organization of full-length POK2, POK2 Δ#4 and POK2 ΔCt. b Root cells in prophase (upper) and cytokinesis (lower) expressing pPOK2::GFP-POK2 Δ#4 and the microtubule reporter RFP-MBD in pok1pok2. GFP signal is cytosolic in prophase and does not co-localize with the preprophase band (bracket and arrow, respectively). In cytokinesis, it decorates exclusively the midzone of the phragmoplast (arrowheads). Note the oblique orientations of the phragmoplasts and the absence from the division site (brackets). c Successive single Z-plane images (time stamp indicates minutes) obtained from live-cell imaging of a cytokinetic cell expressing pPOK2::GFP-POK2 Δ#4 (upper panels). Propidium iodide shows cell walls (merge in lower panels). GFP-POK2 Δ#4 locates to the phragmoplast. Upon phragmoplast expansion towards the adjacent parental cortical regions, initial connections are established (arrow in 04:00), during the course of late cytokinesis, the GFP signal accumulates at the cortex (left arrow in 06:00), later the signal becomes reminiscent of the exploratory microtubules (arrows in 09:00). d–f root meristems, root length, and seedling phenotypes of pok1pok2 expressing no transgene, GFP-POK2 ΔCt, or GFP-POK2 Δ#4. d Root meristems, cell walls visualized by propidium iodide. e Quantification of root length. Box plots show the median, the upper and lower quartiles, and the range of the data. The differences in root length are significant (One-way ANOVA: F = 148.8218, Post Hoc Test: Tukey HSD; p = 0.0010053 (POK2 ΔCt pok1pok2 vs POK2 Δ#4 in pok1pok2); p = 0.0463516 (POK2 ΔCt pok1pok2 vs pok1pok2); p = 0.0010053 pok1pok2 vs POK2 Δ#4 in pok1pok2), pok1pok2, n = 58 roots; POK2 ΔCt, n = 42 roots; n = 52 (3 biological replicates). f Seedling phenotypes (6 days after germination, upper panel) and young plants (lower panel). Source data are provided as Source Data files.