Expression and localization of the GFP-fusion protein.

(A) Expression of FgHTF1 in mycelia of F graminearum transformants ΔFghtf1-GFP grown in CMC medium, which is conducive to spore production. The strain ΔFghtf1-GFP carries a single GFP-carboxy translational fusion of FgHTF1. GFP fluorescence was observed in mycelia at 48 h after inoculation, and each cell contained one fluorescence punctum. Mycelia of ΔFghtf1-GFP were also stained by ethidium bromide (EB), which is a nuclear counterstain for use in multicolor fluorescent techniques and stains nuclei specifically. The merged image of GFP and EB staining showed that ΔFghtf1-GFP localizes to the nucleus (white arrow), Bar = 20 µm. (B) Expression levels of ΔFghtf1-GFP at different time course (24 h, 36 h, 48 h, 60 h and 72 h) after inoculation in CMC medium. qRT-PCR was used to quantify transcript level of FgHTF1 relative to that of the constitutive reference gene β-tubulin using the 2−ΔΔCT method.