Ageratinicola Lu L., K.D. Hyde & Tibpromma, gen. nov.

Index Fungorum number: IF 559942;  MycoBank number: MB 559942; Facesoffungi number: FoF 10844

Etymology – Name refers to the host genus it was isolated from “Ageratina”.

Saprobic on dead or dying stems and branches. Sexual morph: Undetermined. Asexual morph: Conidiomata pycnidial, globose to subglobose, or irregular, solitary or aggregated, immersed with a short neck. Pycnidial walls multi-layered, cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells enteroblastic, doliiform or cylindrical, hyaline. Conidia oval to ellipsoid, or ovoid, muriform, hyaline when young, becoming brown when mature, multi-septate with or without mucilaginous sheath, smooth-walled.

Notes – ITS and LSU sequences of our collection (HKAS 122688) are highly similar to Foliophoma species. The phylogenetic analyses based on ITS, LSU and SSU showed that our collection and Foliophoma species formed a distinct clade with ML/BI = 100%/1.00 statistical support (Fig. 1). However, morphologically, our collection is distinct from Foliophoma species by having brown, muriform conidia, while Foliophoma has hyaline, aseptate and broadly ellipsoidal conidia (Crous and Groenewald 2017). In addition, our collection is also distinct from other genera in Coniothyriaceae by having initially hyaline, oval to ellipsoid, or ovoid conidia becoming brown, multi-septate and muriform at maturity (Sutton 1971; Taylor and Crous 2001; Crous et al. 2007; Crous and Groenewald 2017). Therefore, our collection represents a new monotypic genus and it is introduced here as Ageratinicola gen. nov. and we accommodated Ageratinicola and Foliophoma in new family Ageratinicolaceae.

Figure 1 – Phylogram generated from maximum likelihood analyses based on combined ITS, LSU and SSU sequence data. Thirty taxa were included in the combined analyses, which comprised 2538 characters (ITS=594, LSU=905, SSU=1039). The matrix had 506 distinct alignment patterns, with 24.52% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.251501, C=0.216231, G=0.272433, T=0.259835; substitution rates: AC=1.610597, AG=3.537196, AT=2.613191, CG=0.671725, CT=6.148363, GT=1.0; gamma distribution shape parameter α=0.084053 with a final likelihood value of − 8485.427171. Bootstrap support for maximum likelihood (ML)≥50% and clade credibility values≥0.90 from Bayesian inference analyses are labelled at each node. Ex-type strains are in bold, while the new isolate is indicated in blue bold. The tree is rooted to Ascochyta pisi (CBS 126.54) and Didymella exigua (CBS 183.55)

Species