Figure 1.

External colonization of carnation roots by the virus-free (V⁻) and the virus-infected (V⁺) GFP-strains of Fusarium oxysporum f. sp. dianthi isolate 77. Images were taken using a confocal laser scanning microscope and intact roots sampled at two (A,B) and three (C) days after inoculation with the virus-free strain V⁻ (A,C) or the virus-infected strain V⁺ (B). (A,B) Superficial colonization of adventitious roots by the virus-free (A) and the virus-infected (B) strains showing single and germinating conidia (arrowed). (C) Event of penetration of the root epidermis cells showing the formation of apressoria (ap) on the cell surface, and haustoria (ha) inside the epidermal cell. Scale bar = 50 μm (A,B) and 5 μm (C).