In Northeast of Portugal, the macrofungal community
associated to chestnut tree (Castanea sativa Mill.) is
rich and diversified. Among fungal species, the ectomycorrhizal
Pisolithus tinctorius and the saprotroph Hypholoma
fasciculare are common in this habitat. The aim of the
present work was to assess the effect of the interaction
between both fungi on growth, nutritional status, and
physiology of C. sativa seedlings. In pot experiments, C.
sativa seedlings were inoculated with P. tinctorius and H.
fasciculare individually or in combination. Inoculation with
P. tinctorius stimulated the plant growth and resulted in
increased foliar-N, foliar-P, and photosynthetic pigment
contents. These effects were suppressed when H. fasciculare
was simultaneously applied with P. tinctorius. This result
could be related to the inhibition of ectomycorrhizal fungus
root colonization as a result of antagonism or to the
competition for nutrient sources. If chestnut seedlings have
been previously inoculated with P. tinctorius, the subsequent
inoculation of H. fasciculare 30 days later did not affect root
colonization, and mycorrhization benefits were observed.
This work confirms an antagonistic interaction between
ectomycorrhizal and saprotrophic fungi with consequences
on the ectomycorrhizal host physiology. Although P.
tinctorius is effective in promoting growth of host trees by
establishing mycorrhizae, in the presence of other fungi, it
may not always be able to interact with host roots due to an
inability to compete with certain fungi.
