Neodendryphiella mali Iturrieta-Gonzalez , Gene & Dania Garcia

Iturrieta-Gonzalez, Isabel, Gene, Josepa, Guarro, Josep, Castaneda-Ruiz, Rafael F. & Garcia, Dania, 2018, Neodendryphiella, a novel genus of the Dictyosporiaceae (Pleosporales), MycoKeys 37, pp. 19-38 : 19

Neodendryphiella mali Iturrieta-Gonzalez, Gene & Dania Garcia sp. nov. Fig. 2

Etymology.

Name refers to the substrate, Malus domestica , where the type strain of the species was collected.

Type.

Italy, Dipt. Prot. Valor. Agroalimentare, from leaf of Malus domestica , Feb. 1995, A. Cesari (holotype CBS H-23477, culture ex-type CBS 139.95).

Description.

Mycelium superficial and immersed, composed of septate, branched, smooth to verruculose, hyaline to pale brown hyphae of 1-3 μm wide. Conidiophores semi-macronematous to macronematous, mononematous, erect or slightly flexuous, branched or unbranched, up to 11-septate, cylindrical, up to 385 μm long, 3-4 μm wide, brown, usually darker toward the base, smooth to verrucose. Conidiogenous terminal and intercalary, mostly cylindrical, 8-38 × 3 –4(– 5) μm, with 1-4 pores. Ramoconidia 0-1-septate, with up to 3 terminal and lateral pores, pale brown, smooth to verruculose, mostly cylindrical, (11 –)15–17(– 21) × 3-4 μm. Conidia catenate, with up to 10 conidia in the terminal unbranched part, (0-)1-septate, usually not constricted at the septum, pale brown, verruculose to verrucose, ellipsoidal, doliiform or subcylindrical with more or less rounded ends, 4-15 × 3-5 μm.

Culture characteristics

(14 d at 25 °C). Colonies on PDA reaching 22 mm diam., convex, slightly convoluted at the centre, pastel grey to white (1C1/1A1), aerial mycelium scarce, with slightly fimbriate margin; reverse olive brown to yellowish-brown (4D3/3A2). On PCA attaining 23 mm diam., flat, olive brown to greyish-beige (4F8/4C2), aerial mycelium scarce, slightly fimbriate margin; reverse greyish-beige to brownish-grey (4C2/4D2). On OA reaching 40 mm diam., flat, granular, yellowish-brown to reddish-yellow (5E8/4B7), aerial mycelium scarce, with a regular margin; reverse olive brown to yellowish-brown (4D8/4B7). On SNA attaining 24 mm diam., flat, slightly granular, olive brown to grey (4F8/4B1), aerial mycelium scarce, with fimbriate margin; reverse yellowish-brown (5F7/5E4). On MEA reaching 11-15 mm diam., umbonate, slightly cerebriform towards the periphery, velvety, olive grey (3E2), with irregular margin; reverse olive grey (3E2).

Cardinal temperature for growth.

Optimum 25 °C, maximum 30 °C, minimum 10 °C.

Distribution.

Italy and Spain.

Additional isolates examined.

Spain, Els Ports de Beseit Natural Park, Teruel, from herbivore dung, Oct. 2017, Dania García (FMR 17003)

Notes.

Although LSU sequences of N. mali (CBS 139.95 and FMR 17003) were very similar to those of N. michoacanensis (FMR 16098) and N. tarraconensis (FMR 16234), ITS regions showed a similarity of 96.2% (identities = 441/458, gaps 2/458 (0 %)) with respect to N. michoacanensis and of 92.3% (identities = 423/458, gaps 1/458 (0%)) with respect to N. tarraconensis . ITS sequences of the two latter species described below were 92.1% similar (identities = 422/458, gaps 0/458 (0%)).

Neodendryphilla mali is morphologically very similar to N. michoacanensis since both have conidia and ramoconidia 0-1-septate; however, N. michoacanensis has shorter conidiophores (up to 280 μm long) and terminal conidial branches with fewer conidia (up to 4 per branch), which measure 5 –16(– 18) × 3-6 μm. In addition, 2-septate conidia can also be present in N. michoacanensis and this species tends to grow faster than N. mali on PDA (34 mm vs 22 mm diam. after 14 d, respectively) and PCA (42 mm vs 23 mm diam. after 14 d, respectively). Neodendryphiella mali also resembles D. infuscans , but the latter exhibits longer conidiophores, up to 500 μm and smooth to minutely verruculose conidia with up to 2 septa ( Ellis 1971). However, the protologue of D. infuscans (as Cladosporium infuscans ; Thümen 1879), which was based on a specimen collected in Aiken (USA), describes conidia 0-1-septate, smooth-walled and up to 10 μm long. No living culture of the type specimen was preserved for further comparison.

As mentioned before, the strain CBS 139.95 was identified as Di. asperum and found by other authors to be related with dictyosporium-like fungi ( Shenoy et al. 2010, Tanaka et al. 2015). However, the protologue of Di. asperum was characterised by single or fasciculate conidiophores, which were up to 250 μm long, bearing terminal or subterminal, short and unbranched chains of conidia with only 1 septum ( Pirozynski 1972), morphological features that do not fit with those observed in the above-mentioned strain. We therefore concluded that it was a misidentified strain and clearly represents a different species. At any rate, it is of note that the taxonomy of Di. asperum is controversial because of the different interpretation of the morphological features of Pirozynski’s specimen (DAOM 133941c isotype). Holubová-Jechová (1982) described conidiogenous cells showing inconspicuous denticles or conidiogenous scars instead of the typical pores in conidiogenous cells of Diplococcium and suggested excluding this species from the genus. On the other hand, Goh and Hyde (1998) re-examined the isotype of Di. asperum and observed the typical pores of tretic conidiogenesis, considering it an acceptable species for Diplococcium . However, since only herbarium material is preserved for comparison ( Pirozynski 1972), its phylogeny remains uncertain.