ULTRASTRUCTURE OF INFECTION OF CYST NEMATODE EGGS BY THE NEMATOPHAGOUS FUNGUS VERTICILLIUM-SUCHLASPORIUM

Ultrastructural studies showed that strains of Verticillium suchlasporium isolated from eggs of Heterodera avenae, infected in vitro eggs of H. avenae and Globodera pallida. In H. avenae, V suchlasporium formed appressoria at the point of infection. In serial sections it was observed that a narrow penetration hypha perforated the egg-shell and formed an infection bulb. Other types of penetration hyphae and germinating conidia were also found. Areas of low electron-density were frequently observed, suggesting the secretion of enzymes by V. suchlasporium to weaken the egg-shell. Penetration of eggs of G. pallida was similar to that described for H. avenae, but the egg-shell of G. pallida was twice as hick as that of H. avenae (approximately 500 nm). Ultrastructure of infection of cyst nematode eggs by V suchlasporium has features in common with other nematophagous fungi.