Abstract:
Extracellular, non-flagellar appendages, termed fimbriae are
widespread among fungi. Fungal fimbriae range in diameter from
6-10 nm and exhibit lengths of up to 30 ~m. Fungal fimbriae
have been implicated in several functions: adhesion, conjugation
and flocculation. A possible role of fimbriae in host-mycoparasite
interactions was the focus of this study .
Using electron microscopy, fimbriae were observed on the
surfaces of Mortiere lla cande labrum, Mortie re lla pusi lla and
Phascolomyces articulosus with diameter means of 9.1±0.4 nm,
9.4±0.5 nm and 8.6±0.6 nm, respectively, and lengths of up to 25
~m. Fimbriae were not observed on the surface of the
mycoparasite, Piptocephalis virginiana.
Polyclonal antiserum (AU) prepared against the fimbrial
protein of Ustilago violacea cross-reacted with 60 and 57 kDa M.
candelabrum proteins. In addition, AU cross-reacted with 64 kDa
proteins from both M. pusilla and P. articulosus. The proteins that
cross-reacted with AU were electroeluted from polyacrylamide gels
and were shown to subsequently form fibrils. The diameter means
for the electroeluted fibrils were: for M. candelabrum 9.7±0.3 nm,
M. pusilla 8.4±0.6 nm and P articulosus 9.2±0.5 nm.
Finally, to ascertain the role of fimbriae in host-mycoparasite
interactions, AU was incubated with P. virginiana and M. pusilla
(mycoparasite/susceptible host) and with P. virginiana and P .
articulosus (mycoparasite/ resistant host). It was observed that AU decreased significantly the level of contact between P. virginiana
and M. pusilla and between P. virginiana and P. articulosus in
comparison to prelmmune serum treatments. Thus, it was
proposed that fimbriae might play recognition and attachment roles
in early events of mycoparasitism.
