Interactions between dark septate endophytic fungus Pseudosigmoidea ibarakiensis isolate I.4-2-1 and roots of two host plants.

(A, C) Cross sections of a tomato and a Chinese cabbage root segment stained with 0.005% cotton blue in 50% acetic acid three weeks after inoculation showing fungal hyphae on the root surface, within epidermal cells (EP) (head arrows). VC = vascular cylinder. (B,D) Cross sections of an un-inoculated tomato and a Chinese cabbage root segment serving as controls and showing disruption of vascular cylinder (arrows).