Fungalpedia – Note 1556, Jahniella

 

Jahniella. Petr.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1

Classification: Incertae sedis, Incertae sedis, Incertae sedis, Incertae sedis, Pezizomycotina, Ascomycota, Fungi

 

Pathogenic or saprobic on host plants. The sexual morph is undetermined. The asexual morph is characterised by immersed pycnidial conidiomata, which are dark brown, subepidermal to epidermal, separate, unilocular, and glabrous. The ostiole is circular, papillate, single, with a distinct channel and located in the center. The pycnidial wall is comprised of an out layer of textura angularis, with thin-walled, dark brown cells, a middle layer of pale brown to hyaline, thick-walled cells, and inner layer of thin-walled, hyaline and irregular cells. Conidiophores are reduced to conidiogenous cells. Conidiogenous cells are holoblastic, determinate, ampuliform, hyaline and smooth-walled. Conidia are hyaline, smooth-walled, eguttulate, cylindrical to fusiform, straight or slightly curved, 3–4-septate, apex tapered and base truncate (Petrak 1920, Sutton 1980, Li et al. 2020).

Notes: Jahniella was introduced by Petrak (1920) based on J. bohemica as the type species. In 1980, Jahniella was re-described by Sutton (1980) and accepted three species (J. bohemica, J. campanulae-cervicariae and J. hordei) without molecular data. Jahniella has similar hyaline and multi-septate conidia to Septoria. However, proliferate sympodially and percurrently conidiogenous cells of Septoria differ from Jahniella (this feature is not present) (Sutton 1980, Quaedvlieg et al. 2013). Species Fungorum (September 2024) only lists the type species in Jahniella, however, Mycobank (September 2024) accepts three species. No molecular data is available for this genus in GenBank (September 2024). Wijayawardene et al. (2022) accepted Jahniella belongs to Mycosphaerellaceae (Mycosphaerellales) based on morphological characters. The updated taxonomic treatment of this genus is Mycosphaerellaceae, in Mycosphaerellales (Dothideomycetes) (Wijayawardene et al. 2022).

 

Type species: Jahniella bohemica Petr., Annls mycol. 18(4/6): 123 (1921) [1920].

 

image

 

Figure 1 – Jahniella bohemica (redrawn from Sutton 1980) a Conidia. b Vertical section of conidioma. c Conidiogenous cells and developing conidia. Scale bars: a = 10 μm, b = 100 μm, c = 10 μm. (Originally published in Li et al. (2020) and republished with authority)

 

References

Li WJ, McKenzie EH, Liu JK, Bhat DJ et al. 2020 – Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100, 279–801.

Petrak F. 1920 – Der mykologische Nachlass Josef Jahn’s, ein Betrag zur Pilzflora des Egerlandes. Annales Mycologici 18(4-6), 105–135.

Quaedvlieg W, Barreto RW, Alfenas AC, Barreto RW et al. 2013 – Sizing up Septoria. Studies in Mycology 75, 307–390.

Sutton BC. 1980 – The Coelomycetes. Fungi imperfecti with pycnidia, acervuli and stromata. Commonwealth Mycological Institute, Kew.

Wijayawardene NN, Hyde KD, Dai DQ, Sánchez-García ML et al. 2022 – Outline of Fungi and fungus-like taxa–2021. Mycosphere 13(1), 53–453.

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