Minutisphaerales » Acrogenosporaceae

Acrogenospora

Acrogenospora M.B. Ellis, Dematiaceous Hyphomycetes (Kew): 114 (1971)

 

Saprobic on decaying wood, bark, culms of bamboo in freshwater or terrestrial habitats. Sexual morph: Hysterothecia laterally compressed, with a prominent sunken slit, solitary to gregarious, erect and elevated, presenting an almost stipitate appearance, thick-walled. Pseudoparaphyses branched. Asci 8-spored, cylindrical, fusoid or obovate, obtuse at the apex, short pedicellate, thin-walled. Ascospores oval, aseptate, hyaline or moderately pigmented (Mason 1941; Jayasiri et al. 2018). Asexual morph: Hyphomycetous. Colonies effuse, dark brown to black, glistening, hairy. Mycelium mostly immersed, consist of septate, thin-walled, smooth, hyaline to pale brown hyphae. Conidiophores macronematous, mononematous, solitary, erect, subulate or cylindrical, straight or slightly flexuous, pale brown to dark brown, septate, unbranched, smooth. Conidiogenous cells holoblastic, monoblastic, integrated, terminal or intercalary, with percurrent proliferations, cylindrical. Conidia solitary, dry, acrogenous, simple, spherical, subspherical, olive to brown, aseptate, truncate at the base, smooth or verrucose (Ellis 1971; Hyde et al. 2019).

 

Type species: Acrogenospora sphaerocephala (Berk. & Broome) M.B. Ellis

 

Notes: Acrogenospora is a holomorphic genus, characterized by laterally compressed hysterothecia with a prominent sunken slit, oval, aseptate, hyaline ascospores and spherical, olive to brown conidia (Hyde et al. 2019). Acrogenospora is used to suppress Farlowiella Sacc. (Rossman et al. 2015) and their sexual-asexual connections were linked based on molecular data (Jayasiri et al. 2018). Thus, Acrogenospora is the only genus in Acrogenosporaceae (Jayasiri et al. 2018; Hyde et al. 2019). The sequence data of the type species A. sphaerocephala were generated based on a freshwater collection from Thailand (Hyde et al. 2019). Bao et al. (2020) introduced seven new species collected from a small area of Yunnan Province, China, which indicated Acrogenospora is a speciose genus. 20 species were reported in Acrogenospora and 13 have been confirmed with molecular data (Bao et al. 2020). Freshwater Acrogenospora species are morphologically very similar and the sequence data are main evidence to separate them.

 

List of freshwater Acrogenospora species

*Acrogenospora aquatica D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 3 (2020)

*Acrogenospora basalicellularispora D.F.  Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 8 (2020)

*Acrogenospora ellipsoidea D.M. Hu, L. Cai & K.D. Hyde, Sydowia 62(2): 194 (2010)

*Acrogenospora guttulatispora D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 8 (2020)

*Acrogenospora obovoidspora D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 8 (2020)

*Acrogenospora olivaceospora D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 10 (2020)

Acrogenospora ovalis Goh, K.D. Hyde & C.K.M. Tsui [as ‘ovalia’], Mycol. Res. 102(11): 1312 (1998)

*Acrogenospora sphaerocephala (Berk. & Broome) M.B. Ellis, Dematiaceous Hyphomycetes (Kew): 114 (1971)

*Acrogenospora submersa D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 12 (2020)

*Acrogenospora subprolata Goh, K.D. Hyde & C.K.M. Tsui, Mycol. Res. 102(11): 1314 (1998)

*Acrogenospora thailandica J. Yang & K.D. Hyde, Fungal Diversity 96: 78 (2019)

*Acrogenospora verrucispora Hong Zhu, L. Cai & K.Q. Zhang [as ‘verrucospora’], Mycotaxon 92: 384 (2005)

*Acrogenospora yunnanensis D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su, Frontiers in Microbiology 11: 18 (2020)

 

Key to freshwater Acrogenospora species

1. Conidiophores 850–950 × 3.5–8 µm........................................................ A. thailandica

1. Conidiophores < 800 µm long….................................................................................. 2

2. Conidiophores have wide range of length, 100–730 × 7.2–10.5 µm…. A. sphaerocephala

2. Conidiophores not as above….................................................................................... 3

3. Conidia with a small, hyaline basal cell…...................................................................... 4

3. Conidia without basal cell…......................................................................................... 5

4. Conidiophores 202–250 × 7.5–9.5 µm......................................................... A. Aquática

4. Conidiophores 259–395 × 8–12 µm.......................................... A. basalicellularispora

5. Conidia hyaline when young, darker when mature…............................................ 6

5. Conidia colour almost consistent…............................................................................. 8

6. Conidiophores 163–223 × 6.7–10 µm......................................................... A. submersa

6. Conidiophores > 260 µm long….................................................................................. 7

7. Conidiophores 7.5–8.6 µm wide.......................................................... A. guttulatispora

7. Conidiophores 8.6–12 µm wide….......................................................... A. yunnanensis

8. Conidia verrucose…............................................................................ A. verrucispora

8. Conidia smooth…...................................................................................................... 9

9. Conidia ellipsoidal…................................................................................ A. ellipsoidea

9. Conidia not as above…..............................................................................................10

10. Conidia 24–33 × 18–22 µm…........................................................................ A. ovalia

10. Conidia > 32 µm long….......................................................................................... 11

11. Conidia 39–46 × 30–39 µm…................................................................ A. subprolata

11. Conidia < 39 µm long….......................................................................................... 12

12. Conidiophores  209–277  ×  7.5–10  µm............................................ A. obovoidspora

12. Conidiophores 102–172 × 5.8–9 µm................................................. A. Olivaceospora

 

References

Bao DF, McKenzie EHC, Bhat DJ, Hyde KD, Luo ZL, Shen HW, Su HY (2020) Acrogenospora (Acrogenosporaceae, Minutisphaerales) appears to be a very diverse genus. Frontiers in Microbiology 11:1606

Ellis MB (1971) Dematiaceous hyphomycetes. Commonwealth Mycological Institute, Surrey, England

Hyde KD, Tennakoon DS, Jeewon R, Bhat DJ et al. (2019) Fungal diversity notes 1036–1150: taxonomic and phylogenetic contributions on genera and species of fungal taxa. Fungal Divers 96:1–242

Jayasiri SC, Hyde KD, Jones EBG, Peršoh D, Camporesi E, Kang JC (2018) Taxonomic novelties of hysteriform Dothideomycetes. Mycosphere 9:803–837

Mason EW (1941) Annotated account of fungi received at the Imperial Bureau of Mycology. Myc Papers 5:101–144

Rossman AY, Crous PW, Hyde KD, Hawksworth DL, Aptroot A, Bezerra JL, Bhat DJ, Boehm E, Braun U, Boonmee S (2015) Recommended names for pleomorphic genera in Dothideomycetes. IMA fungus 6:507–523

 

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