Dual life history of Biscogniauxia barriae sp. nov. (Xylariales, Graphostromataceae) as a Douglas-fir foliar endophyte and hardwood saprotroph.

Biscogniauxia species are typically recognized by carbonaceous stromata on woody substrates, but some also occur as asymptomatic endophytes and may shift ecological roles across hosts and substrates. Here, Biscogniauxia barriae sp. nov. is described, first isolated as a foliar endophyte from asymptomatic Douglas-fir (Pseudotsuga menziesii) needles in coastal British Columbia and later found producing stromata on dead hardwoods, including bigleaf maple (Acer macrophyllum), red alder (Alnus rubra), and hawthorn (Crataegus sp.). Phylogenetic analyses of ITS, BenA, and RPB2 resolved B. barriae as a distinct, well-supported lineage within Biscogniauxia s.s., sister to B. capnodes and allied with a clade including B. anceps and B. nummularia. The species is characterized by applanate to pulvinate, carbonaceous stromata with coarsely papillate ostioles and dark brown, broadly ellipsoid ascospores with a conspicuous straight germ slit; a nodulisporium-like asexual morph is produced in culture. The highly complete 42.7 Mb draft genome contained 10,986 predicted protein-coding genes and was broadly comparable to available Biscogniauxia genomes. Orthogroup analyses indicated extensive conservation of protein-coding gene content, while identification of a MAT1-2 idiomorph suggests heterothallism. The discovery of B. barriae through both Douglas-fir endophyte surveys and hardwood stromatal collections highlights a dual life history linking conifer foliar endophytism with hardwood-associated saprotrophy or possible latent pathogenicity. Strong inhibition of the in vitro growth of Nothophaeocryptopus gaeumannii, the causal agent of Swiss needle cast, by culture-filtrate extracts of B. barriae suggests potential ecological relevance within the Douglas-fir needle mycobiome.