Pyriculariomyces

Y. Marín, M.J. Wingf. & Crous, gen. nov. MycoBank MB823760. Fig. 51. Table 17.
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Fig. 51. Pyriculariomyces asari (ex-type CBS 141328). A. Ascomata on host tissue. B. Section of ascoma. C–E. Asci and ascospores. F. Conidiophores on SNA. G, H. Conidiophores and conidia. I. Conidia. Scale bars: B = 100 μm; others = 10 μm; C applies to C, D; G applies to G, I. Pictures A, B, D, E, G, H taken from Crous et al. (2016b).

Table 17. DNA barcodes of accepted Pyriculariomyces sp.

Species Isolates1 GenBank accession numbers2 References
ITS act cal rpb1
Pyriculariomyces asari CBS 141328T KX228291 KX228361 MG934541 KX228368 Crous et al. (2016b), present study
CPC 27442 KX228290 KX228360 – MG934472 Crous et al. (2016b), present study
1

CBS: Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands; CPC: Culture collection of Pedro Crous, housed at Westerdijk Fungal Biodiversity Institute. T indicates ex-type strain.

2

ITS: internal transcribed spacers and intervening 5.8S nrDNA; act: partial actin gene; cal: partial calmodulin gene; rpb1: partial RNA polymerase II largest subunit gene.

Etymology: Named after the genus Pyricularia, which it resembles morphologically.

Ascomata separate, immersed, globose, brown, with central papillate neck and ostiole; ascomatal wall of 2–4 layers of brown cells of textura angularis. Hamathecium dissolving upon maturity, with some cells remaining among asci. Asci unitunicate, hyaline, smooth, 8-spored, subcylindrical, stipitate, apical mechanism refractive, but not staining in Meltzer’s. Ascospores biseriate, fusoid-ellipsoid, widest in middle, tapering towards subobtusely rounded ends, slightly curved to straight, 3-septate, pale brown, guttulate. Conidiophores solitary, erect, straight to flexuous, unbranched, subcylindrical, brown, smooth, 1–8-septate. Conidiogenous cells integrated, terminal, apex somewhat swollen with numerous denticle-like loci, slightly thickened and darkened. Conidia solitary, pyriform, brown, finely verruculose, guttulate, granular, apex subobtusely rounded, with or without mucoid cap, base truncate, hilum darkened, thickened, 2-septate.

Culture characteristics: Colonies reaching 90 mm after 2 wk at 25 °C, with moderate aerial mycelium and smooth, even margins. On MEA surface pale mouse grey with patches of dirty white; reverse isabelline with patches of pale luteous. On OA surface honey with patches of pale mouse grey. On PDA surface honey; reverse isabelline to honey.

Type species: Pyriculariomyces asari (Crous & M.J. Wingf.) Y. Marín, M.J. Wingf. & Crous. Holotype and ex-type cultures: CBS H-22625, CBS 141328 = CPC 27444.

Notes: Pyriculariomyces is phylogenetically closely related to Pyricularia. However, Pyriculariomyces can easily be distinguished by production of integrated terminal conidiogenous cells, while Pyricularia produces terminal and intercalary conidiogenous cells. In Pyriculariaceae, the only genera characterised by only terminal conidiogenous cells are Barretomyces and Utrechtiana. However, these genera can easily be distinguished from Pyriculariomyces by the septation of the conidia i.e. 4(–5)-septate in Barretomyces and 1–2-septate in Utrechtiana. Moreover, Utrechtiana differs in the presence of conidiogenous cells that proliferate percurrently. Moreover, Pyriculariomyces can be distinguished from Pyricularia by the production of ascomata with papillate necks with ostioles, while Pyricularia is characterised by ascomata with long necks.

Pyriculariomyces asari

(Crous & M.J. Wingf.) Y. Marín, M.J. Wingf. & Crous, comb. nov. MycoBank MB823761. Fig. 51.

Basionym: Proxipyricularia asari Crous & M.J. Wingf., Persoonia 36: 393. 2016.

Description: Crous et al. (2016b).

Materials examined: Malaysia, Sabah, on leaves and stems of Asarum sp. (Aristolochiaceae), May 2015, M.J. Wingfield (holotype CBS H-22625, culture ex-type CPC 27444 = CBS 141328); ibid., CPC 27442.

Notes: Pyriculariomyces asari was introduced as a species of Proxypiricularia to accommodate two specimens collected from Asarum (Crous et al. 2016b). However, the authors at the time suggested that this species could represent another genus in the Pyricularia complex. The phylogenetic analysis generated here based on four different loci (Fig. 28), support this hypothesis.

Authors: Y. Marin-Felix, M.J. Wingfield & P.W. Crous