Hyphae of waxcap fungi colonise plant roots

The trophic strategy of the globally distributed waxcaps
(Hygrophoraceae) is uncertain. Some clues point to a biotrophic mode,
particularly the 13C and 15N (stable isotopes) signatures. The
observation of dense basal hyphae of Hygrocybe fruit bodies being tightly
attached to live fine roots may be indicative of a plant-derived
nutritional habit. To further scrutinize this fungus-plant association,
stipe base samples and attached plant fragments were examined
histologically. Waxcap hyphae were found growing inside live fine roots
of associated vegetation. Amplication and sequencing of waxcap DNA from
living root tissues using species-specific PCR primers also confirmed
their presence in live plant roots. We therefore conclude that this group
of fungi has a biotrophic lifestyle with plants.