Phomatodes nebulosa (Pers.) Qian Chen & L. Cai, Stud. Mycol. 82: 191 (2015)

Wijesinghe, Subodini N., Wang, Yong, Zucconi, Laura, Dayarathne, Monika C., Boonmee, Saranyaphat, Camporesi, Erio, Wanasinghe, Dhanushka N. & Hyde, Kevin D., 2021, Additions to Italian Pleosporinae, including Italica heraclei sp. nov., Biodiversity Data Journal 9, pp. 59648-59648 : 59648

Phomatodes nebulosa (Pers.) Qian Chen & L. Cai, Stud. Mycol. 82: 191 (2015)

Phomatodes nebulosa Sphaeria nebulosa

Sphaeria nebulosa = Sphaeria nebulosa Pers., Observ. mycol. (Lipsiae) 2: 69 (1800) [1799]

Materials

Type status: Other material. Occurrence: recordedBy: Erio Camporesi; Taxon: namePublishedIn: Phomatodes nebulosa (Pers.) Qian Chen & L. Cai, Stud. Mycol. 82: 191 (2015); kingdom: Fungi; phylum: Ascomycota; class: Dothideomycetes; order: Pleosporales; family: Didymellaceae; genus: Phomatodes; specificEpithet: nebulosa; taxonRank: species; Location: stateProvince: Province of Arezzo [AR]; county: Italy; municipality: near Passo la Calla - Stia; Identification: identifiedBy: S.N. Wijesinghe; Event: year: 2018; month: December; day: 3; habitat: on a dead and aerial stem of Urtica dioica (Rosales, Urticaceae); fieldNotes: Terrestrial; Record Level: institutionID: MFLU 18-2685; institutionCode: Mae Fah Luang University Herbarium (MFLU); ownerInstitutionCode: IT 4110 Type status: Other material. Record Level: type: living culture; collectionID: MFLUCC 20-0155; collectionCode: Mae Fah Luang Culture Collection (MFLUCC)

Description

Saprobic on dead aboveground stem of Urtica dioica L. ( Rosales , Urticaceae ). Asexual morph: Coelomycetous. Conidiomata (Fig. 5 a-c) immersed, raised as black spots on the host surface, pycnidial, 60-70 × 140-170 µm (x¯ = 66.5 × 155 µm, n = 10), solitary, scattered, unilocular, globose or subglobose to irregular. Pycnidial wall (Fig. 5 d) pseudoparenchymatous, 3-5-layered, 15-30 µm (x¯ = 25 µm, n = 10) wide, thick walled, the outermost layer comprising dark brown cells of textura angularis, the inner layer comprising pale brown to hyaline cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells (Fig. 5 e-f) 4-5 × 2-4 µm (x¯ = 4.5 × 3.6 µm, n = 5), enteroblastic, phialidic, ampulliform or short cylindrical, determinate, smooth, hyaline. Conidia (Fig. 5 g-j) 4-7 × 1-2 µm (x¯ = 5.3 × 1.6 µm, n = 30) ellipsoidal to cylindrical, aseptate, guttulate, smooth-walled, hyaline. Sexual morph: Undetermined.

Culture characteristics: Conidia germinating on PDA within 24 h, from single-spore isolation. Colonies (Fig. 5 l-m) on PDA reaching 5-10 mm diam. after 10 days at 18°C, circular, entire edge, flat, dense, white in both upper and lower sides.

GenBank accession numbers (ex-MFLUCC 20-0155): ITS = MT880293, LSU = MT880295, TUB2 = MT901291

Notes

Phomatodes was introduced by Chen et al. (2015) to accommodate Phoma -like taxa in Didymellaceae . The type species, Phomatodes aubrietiae , is characterised by globose to subglobose pycnidia, ostiolate conidiomata, solitary or confluent, with a 3-5-layered, pigmented pseudoparenchymatous pycnidial wall, phialidic, hyaline, smooth, ampulliform to doliiform conidiogenous cells and cylindrical to allantoid, hyaline, thin-walled, smooth, aseptate, polar guttulate conidia ( Chen et al. 2015). The morphology of our material (Fig. 5 ) agrees with that of the holotype (CBS 100191), with globose to subglobose conidiomata; phialidic, ampulliform conidiogenous cells; and hyaline, aseptate and polar guttulate conidia (5-7 × 1.5-2.5 µm).

From the comparison of ITS, LSU and TUB2 sequences between P. nebulosa (CBS 100191-type) and P. nebulosa (MFLUCC 20-0155), both strains were identical. In our multi-locus phylogenetic analyses, the new isolate (MFLUCC 20-0155) and the ex-type strains of P. nebulosa (CBS 117.93, CBS 740.96, CBS 100191, MFLU 18-0177) clustered together with high support (99 ML/1.00 PP) (Fig. 2 ).

Early records of Phomatodes nebulosa were reported on Armoracia rusticana ( Brassicales , Brassicaceae ) and Mercurialis perennis ( Malpighiales , Euphorbiaceae ) from the Netherlands, Thlaspi arvense ( Brassicales , Brassicaceae ) from Poland ( Chen et al. 2015, Farr and Rossman 2020) and Datisca cannabina ( Cucurbitales , Datiscaceae ) from Uzbekistan ( Gafforov 2017, Farr and Rossman 2020). Our new strain of P. nebulosa from U. dioica was collected from the Province of Arezzo in Italy at higher altitude (296 m a.s.l.), compared to the previous Italian record on the same host, but from the Province of Forlì-Cesena (34 m a.s.l.) ( Hyde et al. 2020a). Considering the results of our integrative taxonomic approach, we report this strain as a new record of P. nebulosa , the first for the Province of Arezzo and the second for Italy, widening its geographic distribution in the country.

Figures

Figure 2. Phylogeny of the family Didymellaceae, reconstructed from the combined ITS-LSU-RPB 2 - TUB 2 dataset. Leptosphaeria conoidea (CBS 616.75) and L. doliolum (CBS 505.75) serve as outgroup taxa. ML = 70 and PP = 0.95 are presented above each node. The new isolate is indicated in bold; T = type strains. The scale bar represents the expected number of nucleotide substitutions per site.

Figure 5. Phomatodes nebulosa (MFLU 18 - 2685). a-b. Conidiomata on a dead stem of Urtica dioica Rosales, Urticaceae). c. Longitudinal section of a conidioma. d. Conidiomatal wall. e-f. Development stages of conidiogenesis. g-j. Conidiospores. k. Germinating conidium. l-m. Colonies on PDA (l upper, m lower). Scale bars: a = 100 µm, c = 50 µm, b, k = 20 µm, d-e = 10 µm, f-j = 5 µm.