Phenotypes of the kinA ^K895 * mutant and various diploids. (A) Images of GFP-TubA (Microtubule; Han et al., 2001) and mCherry-ClipA (ClipA/CLIP170; Zeng et al., 2014) in wild type and the kinA^K895* mutant, showing normal microtubule polarity in the kinA^K895* mutant. Hyphal tip is indicated by a yellow arrowhead. Bar, 5 μm. Note that 21 randomly chosen wild-type hyphae all show normal microtubule polarity, and 93.3% of 45 randomly chosen kinA^K895* mutant hyphae show normal microtubule polarity indicated by microtubule plus ends pointing towards the hyphal tip. In the small number of hyphal tips where we observed microtubule plus ends pointing away from the hyphal tip, the microtubule polarity might still be correct but these microtubules appeared to curl around the hyphal tip, possibly due to an increase in microtubule stability. (B) Images of germ tubes showing nuclei labeled with histone H1-GFP (Xiong and Oakley 2009) in wild type and the kinA^K895* mutant. The spore head is indicated by a yellow arrowhead. Bar, 5 μm. (C) A quantitative analysis on the percent of germ tubes containing different numbers of nuclei in the spore head. Column bar graphs with mean and SD values were generated from three experiments (for each experiment, at least 30 hyphae from each strain were counted, and the total n number for wild type is 164, and that for the mutant is 195). Significantly more wild-type germ tubes contain one nucleus in the spore head, while significantly more kinA^K895* germ tubes contain two nuclei in the spore head (P < 0.0001 in both cases, two-way ANOVA with Bonferroni’s multiple comparisons test). (D) A quantitative analysis on the distance from the hyphal tip to its most proximal nucleus (n = 30 for wild type and n = 31 for the kinA^K895* mutant, unpaired t test, two-tailed, Prism 9). (E) Line scans of GFP-dynein fluorescence intensity in wild type, the kinA^K895* single mutant, the ∆hookA single mutant, and the kinA^K895*, ∆hookA double mutant. XY graphs with mean (solid lines) and SEM (shading) were generated by Prism 9. All values are relative to the peak mean value for wild type, which is set as 1. GFP-dynein intensity near the hyphal tip (between 0.130 and 1.625 μm from hyphal tip) was significantly higher in the kinA^K895* single mutant, the ∆hookA single mutant or the kinA^K895*, ∆hookA double mutant than in wild type (P < 0.0001, two-way ANOVA with Tukey’s multiple comparisons test, n = 40 hyphae for all strains). (F) Microscopic images showing the distributions of mCherry-RabA-labeled early endosomes in four different diploids. Hyphal tip is indicated by a yellow arrowhead. Bar, 5 μm. (G) A quantitative analysis on the percentage of hyphal tips with the abnormal accumulation of early endosomes. Three experiments were performed, and in each experiment, 30 or more hyphal tips were examined for each strain. Scatter plots with mean and SD values were generated by Prism 9 (the P values were generated from ordinary one-way ANOVA, unpaired).