Griseofulvin-producing Xylaria endophytes of Pinus strobus and Vaccinium angustifolium: evidence for a conifer-understory species endophyte ecology

During three decades of research on conifer endophytes of the Acadian forest, numerous insights have been gained in conifer-fungal ecology and secondary metabolite production. Recently, we have explored endophyte assemblages of understory plants commonly occurring with pine. Here we report for the first time the production of the potent antifungal compound griseofulvin by a fungal endophyte isolated from eastern white pine (Pinus strobus) needles and lowbush blueberry (Vaccinium angustifolium) stems from the Acadian forest of New Brunswick and Nova Scotia, Canada. Maximum likelihood phylogenetic analysis has placed the endophyte strains as an undescribed Xylaria sp. Our study highlights the complexity of endophyte-host lifecycles and points to the existence of a pine-blueberry ecotype. Aside from griseofulvin, piliformic acid was isolated from one of the pine endophytes. This compound has been reported from Xylaria and related species but not from Penicillium species known to produce griseofulvin.