C. Sbrana et al., Adhesion to hyphal matrix and antifungal activity of Pseudomonas strains isolated from Tuber borchii ascocarps, CAN J MICRO, 46(3), 2000, pp. 259-268
Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to
produce phytoregulatory and biocontrol substances in pure culture, were us
ed to perform studies on their possible physiological role in nature. Antim
ycotic activity was confirmed against fungal contaminants isolated from the
ascocarps, suggesting that populations associated with Tuber borchii fruit
bodies may play a role in the maintenance of ascocarp health. Fifty-five p
ercent of strains tested were also able to release metabolites which affect
ed T. borchii mycelial growth and morphogenesis in culture. On the contrary
, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomy
corrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorr
hizal infection sites on roots, was not influenced by the presence of any b
acterial strain. The possibility that these bacteria, which show antifungal
activity and fungal growth modulation activities, might be incorporated in
the developing ascocarp by means of their preferential adhesion to Tuber m
ycelium is discussed.