Aberrant ΔFghtf1 macroconidia can germinate and are pathogenic to host.

(A) Germination of wild-type PH-1 and mutant ΔFghtf1 macroconidium in CM. The cells were first observed with a DIC microscope, and subsequently stained with calcofluor white (CFW) to visualize cell walls and septas, respectively, under a fluorescence microscope. Bar = 20 µm. (B) Wheat heads were point-inoculated in the two central spikelets each with 200 conidia of PH-1 and ΔFghtf1. Control wheat heads were point-inoculated with distilled water. Infection assay was terminated after 21 days. (C) Infected wheat coleoptiles inoculated with conidia of the PH-1 and ΔFghtf1. The brown lesions observed on coleoptiles (in length and discoloration intensity) were not distinguishable in PH-1 and ΔFghtf1 samples. (D) Corn stalks were inoculated with toothpicks carrying a mycelium block of PH-1 and ΔFghtf1. Infected corn stalks were split longitudinally at the inoculation sites and examined 14 days post inoculation.