Delay in isotropic to polarized growth transition during germination of small vs. large spores.

(A) Large spores (R7B) have a very short isotropic growth stage or bypass it entirely to send germ tubes. (B) Small spores (NRRL3631) grow isotropically to reach the size comparable to that of large spores, and then germ tubes emerge. Time-lapse (every ∼15 min) images of each strain are presented. Note that in panel B, there are 3 rows of images to show the delay (∼225 mins) prior to germ tube emergence in the smaller (+) spores. See Videos S1 and S2 for corresponding videos. Scale = 40 µm. (C) When isotropically grown, the enlarged (+) spores became as virulent as larger spores in the wax moth larva host (p = 0.9878).