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Phylogenetic circumscription of Arthrographis (Eremomycetaceae, Dothideomycetes).

Giraldo A, Gené J, Sutton DA, Madrid H, Cano J, Crous PW, Guarro J - Persoonia (2014)

Bottom Line: Based on these results, four new species are recognised, namely Arthrographis chlamydospora, A. curvata, A. globosa and A. longispora.Arthrographis longispora also produces membranous colonies, but has poorly differentiated conidiophores and long arthroconidia.Morphological variants are described for A. kalrae and our results also revealed that Eremomyces langeronii and A. kalrae, traditionally considered the sexual and asexual morphs of the same species, are not conspecific.

View Article: PubMed Central - PubMed

Affiliation: Unitat de Micologia, Facultat de Medicina i Ciències de la Salut and IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Tarragona, Spain;

ABSTRACT
Numerous members of Ascomycota and Basidiomycota produce only poorly differentiated arthroconidial asexual morphs in culture. These arthroconidial fungi are grouped in genera where the asexual-sexual connections and their taxonomic circumscription are poorly known. In the present study we explored the phylogenetic relationships of two of these ascomycetous genera, Arthrographis and Arthropsis. Analysis of D1/D2 sequences of all species of both genera revealed that both are polyphyletic, with species being accommodated in different orders and classes. Because genetic variability was detected among reference strains and fresh isolates resembling the genus Arthrographis, we carried out a detailed phenotypic and phylogenetic analysis based on sequence data of the ITS region, actin and chitin synthase genes. Based on these results, four new species are recognised, namely Arthrographis chlamydospora, A. curvata, A. globosa and A. longispora. Arthrographis chlamydospora is distinguished by its cerebriform colonies, branched conidiophores, cuboid arthroconidia and terminal or intercalary globose to subglobose chlamydospores. Arthrographis curvata produced both sexual and asexual morphs, and is characterised by navicular ascospores and dimorphic conidia, namely cylindrical arthroconidia and curved, cashewnut-shaped conidia formed laterally on vegetative hyphae. Arthrographis globosa produced membranous colonies, but is mainly characterised by doliiform to globose arthroconidia. Arthrographis longispora also produces membranous colonies, but has poorly differentiated conidiophores and long arthroconidia. Morphological variants are described for A. kalrae and our results also revealed that Eremomyces langeronii and A. kalrae, traditionally considered the sexual and asexual morphs of the same species, are not conspecific.

No MeSH data available.


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Arthrographis kalrae. a–c. Colonies on PDA after 21 d at 25 °C; d–f. colonies on MEA 2 % at 25 °C after 21 d; g. branched conidiophores; h. lateral sessile conidia; i, j. pigmented chlamydospores and hyaline arthroconidia; k, l. whorls of short arthroconidial chains; m. sterile ascoma (a, d. CBS 693.77; b, e. UTHSC 09-141; c, f–h, k–m. UTHSC 05-17; i, j. UTHSC 11-1256). — Scale bars = 10 μm.
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Figure 3: Arthrographis kalrae. a–c. Colonies on PDA after 21 d at 25 °C; d–f. colonies on MEA 2 % at 25 °C after 21 d; g. branched conidiophores; h. lateral sessile conidia; i, j. pigmented chlamydospores and hyaline arthroconidia; k, l. whorls of short arthroconidial chains; m. sterile ascoma (a, d. CBS 693.77; b, e. UTHSC 09-141; c, f–h, k–m. UTHSC 05-17; i, j. UTHSC 11-1256). — Scale bars = 10 μm.

Mentions: Most of the strains included in the A. kalrae clade (Fig. 2) showed the typical phenotypic characters described for the species; i.e., colonies at 25 °C with slow to moderate growth (up to 10–21 mm diam after 10 d on PDA), flat to slightly folded, initially beige and moist with a yeast-like appearance, becoming tan or yellowish and powdery to granular (Fig. 3a–f); conidiophores hyaline and usually branched (Fig. 3g); conidiogenous hyphae hyaline, simple or branched; arthroconidia 1-celled, hyaline, smooth-walled, cylindrical with truncate ends, 2.5–9 × 1–2 μm. All strains formed a trichosporiella-like synasexual morph with sessile, globose to subglobose, hyaline, thin and smooth-walled conidia, 2–4 × 2–3 μm (Fig. 3h). Several strains showed some atypical characters not previously described for this species. The strains UTHSC 02-1022, UTHSC 06-982, UTHSC 07-2450, UTHSC 08-1804, UTHSC 08-2107, UTHSC 10-1652, UTHSC 10-2583 and UTHSC 11-1256 produced intercalary or terminal chlamydospores with smooth or slightly rugose walls. While in most of these isolates the chlamydospores were hyaline to subhyaline, those of strain UTHSC 11-1256 turned brown on PDA and OA (Fig. 3i, j) giving a dark pigmentation to the colony. The UTHSC 05-17 strain showed a predominance of small conidiophores (up to 70 μm long) composed of a terminal whorl of numerous short chains of clavate or cylindrical arthroconidia with rounded ends (Fig. 3k, l); in old cultures (12 wk) this isolate developed immature ascomata submerged in the agar of all media tested. These ascomata were spherical, non-ostiolate, 37–70 μm diam, with a dark brown, pseudoparenchymatous peridium of textura angularis, surrounded by brown hyphae (Fig. 3m).


Phylogenetic circumscription of Arthrographis (Eremomycetaceae, Dothideomycetes).

Giraldo A, Gené J, Sutton DA, Madrid H, Cano J, Crous PW, Guarro J - Persoonia (2014)

Arthrographis kalrae. a–c. Colonies on PDA after 21 d at 25 °C; d–f. colonies on MEA 2 % at 25 °C after 21 d; g. branched conidiophores; h. lateral sessile conidia; i, j. pigmented chlamydospores and hyaline arthroconidia; k, l. whorls of short arthroconidial chains; m. sterile ascoma (a, d. CBS 693.77; b, e. UTHSC 09-141; c, f–h, k–m. UTHSC 05-17; i, j. UTHSC 11-1256). — Scale bars = 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4150071&req=5

Figure 3: Arthrographis kalrae. a–c. Colonies on PDA after 21 d at 25 °C; d–f. colonies on MEA 2 % at 25 °C after 21 d; g. branched conidiophores; h. lateral sessile conidia; i, j. pigmented chlamydospores and hyaline arthroconidia; k, l. whorls of short arthroconidial chains; m. sterile ascoma (a, d. CBS 693.77; b, e. UTHSC 09-141; c, f–h, k–m. UTHSC 05-17; i, j. UTHSC 11-1256). — Scale bars = 10 μm.
Mentions: Most of the strains included in the A. kalrae clade (Fig. 2) showed the typical phenotypic characters described for the species; i.e., colonies at 25 °C with slow to moderate growth (up to 10–21 mm diam after 10 d on PDA), flat to slightly folded, initially beige and moist with a yeast-like appearance, becoming tan or yellowish and powdery to granular (Fig. 3a–f); conidiophores hyaline and usually branched (Fig. 3g); conidiogenous hyphae hyaline, simple or branched; arthroconidia 1-celled, hyaline, smooth-walled, cylindrical with truncate ends, 2.5–9 × 1–2 μm. All strains formed a trichosporiella-like synasexual morph with sessile, globose to subglobose, hyaline, thin and smooth-walled conidia, 2–4 × 2–3 μm (Fig. 3h). Several strains showed some atypical characters not previously described for this species. The strains UTHSC 02-1022, UTHSC 06-982, UTHSC 07-2450, UTHSC 08-1804, UTHSC 08-2107, UTHSC 10-1652, UTHSC 10-2583 and UTHSC 11-1256 produced intercalary or terminal chlamydospores with smooth or slightly rugose walls. While in most of these isolates the chlamydospores were hyaline to subhyaline, those of strain UTHSC 11-1256 turned brown on PDA and OA (Fig. 3i, j) giving a dark pigmentation to the colony. The UTHSC 05-17 strain showed a predominance of small conidiophores (up to 70 μm long) composed of a terminal whorl of numerous short chains of clavate or cylindrical arthroconidia with rounded ends (Fig. 3k, l); in old cultures (12 wk) this isolate developed immature ascomata submerged in the agar of all media tested. These ascomata were spherical, non-ostiolate, 37–70 μm diam, with a dark brown, pseudoparenchymatous peridium of textura angularis, surrounded by brown hyphae (Fig. 3m).

Bottom Line: Based on these results, four new species are recognised, namely Arthrographis chlamydospora, A. curvata, A. globosa and A. longispora.Arthrographis longispora also produces membranous colonies, but has poorly differentiated conidiophores and long arthroconidia.Morphological variants are described for A. kalrae and our results also revealed that Eremomyces langeronii and A. kalrae, traditionally considered the sexual and asexual morphs of the same species, are not conspecific.

View Article: PubMed Central - PubMed

Affiliation: Unitat de Micologia, Facultat de Medicina i Ciències de la Salut and IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Tarragona, Spain;

ABSTRACT
Numerous members of Ascomycota and Basidiomycota produce only poorly differentiated arthroconidial asexual morphs in culture. These arthroconidial fungi are grouped in genera where the asexual-sexual connections and their taxonomic circumscription are poorly known. In the present study we explored the phylogenetic relationships of two of these ascomycetous genera, Arthrographis and Arthropsis. Analysis of D1/D2 sequences of all species of both genera revealed that both are polyphyletic, with species being accommodated in different orders and classes. Because genetic variability was detected among reference strains and fresh isolates resembling the genus Arthrographis, we carried out a detailed phenotypic and phylogenetic analysis based on sequence data of the ITS region, actin and chitin synthase genes. Based on these results, four new species are recognised, namely Arthrographis chlamydospora, A. curvata, A. globosa and A. longispora. Arthrographis chlamydospora is distinguished by its cerebriform colonies, branched conidiophores, cuboid arthroconidia and terminal or intercalary globose to subglobose chlamydospores. Arthrographis curvata produced both sexual and asexual morphs, and is characterised by navicular ascospores and dimorphic conidia, namely cylindrical arthroconidia and curved, cashewnut-shaped conidia formed laterally on vegetative hyphae. Arthrographis globosa produced membranous colonies, but is mainly characterised by doliiform to globose arthroconidia. Arthrographis longispora also produces membranous colonies, but has poorly differentiated conidiophores and long arthroconidia. Morphological variants are described for A. kalrae and our results also revealed that Eremomyces langeronii and A. kalrae, traditionally considered the sexual and asexual morphs of the same species, are not conspecific.

No MeSH data available.


Related in: MedlinePlus