FvHtf1 regulates microconidiation in chain and false head.

(A) Light microscope images of microconidiogenesis in wild-type F. verticillioides (A149), FvHTF1 gene-deletion mutant (ΔFvhtf1) and complementated strain (ΔFvhtf1-Com). Chains and false heads of microconidia were evidently observed in F. verticillioides A149 and ΔFvhtf1-Com. In ΔFvhtf1 mutant, microconidial chains were absent and instead microconidia were assembled in a aberrant petal-shaped false heads (a∼c). Bar = 50 µm. (B) Scanning electron microscopy of A149 and ΔFvhtf1 microconidiation. Wild-type strain A149 showed the typical chains and false heads of microconidia (bar = 10 µm), but ΔFvhtf1 failed to produce microconidial chains and instead produced false heads with 2 to 5 microconidia at the apex of monophialides resulting in a floral petal shape (bar = 5 µm). (C) Microconidia produced by A149, ΔFvhtf1, and ΔFvhtf1-Com in a 7-day-old mung bean agar culture. (D) Microconidia produced by A149, ΔFvhtf1, and ΔFvhtf1-Com in a 7-day-old SNA culture.