Taphrina viridis (Sadeb.) Maire

Caboňová, Michaela, Vadkertiová, Renáta, Adamčík, Slavomír, Bacigálová, Kamila, Slovák, Marek, Zaib, Shanza & Caboň, Miroslav, 2024, Taxonomic reintroduction of Taphrina viridis (Taphrinales, Ascomycota) associated with Alnus alnobetula as one of five well defined European species colonizing alders, MycoKeys 108, pp. 249-267 : 249-267

Taphrina viridis (Sadeb.) Maire , Bull. Soc. Bot. Fr. 57: CLXVII (1912) [1910]

Exoascus viridis Sadeb. in Jaap, Deutsch. Bot. Monatsschr. 19: 76 (1901). Basionym.

= Taphrina alnastri Lagerheim in Vestergren, Micr. Rar. Sel.: No. 720 (1903).

Neotype

(here designated; MycoBank: MBT#10018607) : • Slovakia; Vysoké Tatry Mts., Žiarska dolina valley ; 1050 m a. s. l., on leaves of Alnus alnobetula ; 31. 7. 2015; leg. K. Bacigálová; SAV ( BU 094 ), deposited in herbarium at the Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences (SAV).

Ex-type culture.

CCY 58-9 - 1 (= SAV BU 094), deposited in Culture Collection of Yeasts, Institute of Chemistry, Slovak Academy of Sciences ( CCY). Sequence accession numbers: ITS PQ 013128, LSU PQ 013143, mtSSU PQ 013155, tef 1 a PP 997889.

Symptoms in vivo.

Taphrina viridis induces the development of small, rounded or irregularly shaped, pale green to yellow-green 5–10 mm large lesions on the upper or lower leaf surfaces of Alnus alnobetula , which in stage of mature asci become coated with a grey-white layer (Fig. 3 A – D ).

Description in vivo.

Vegetative mycelium grows subcuticulary in intercellular spaces of leaf tissues (Fig. 4 A, B ) and is composed of narrow, thick-walled cells, variable in length and shape, divided by layered septa, later mature into globose ascogenous cells. In the late stages of infection, ascogenous cells broaden and form asci, penetrating the epidermal layer of the leaf tissue. The asci are ovoid to ellipsoid, 21.9–24.5 – 27.1 × 11–11.8 – 12.8 μm (Fig. 4 C, D ). The apical parts of asci are mainly rounded or truncated with pale, translucent oil drops, the asci contain 8 spores. The ascospores are globose to ellipsoid, 5.3–6.5 – 7.7 × 3.9–4.4 – 4.9 μm (Fig. 4 E ); the ascospores budding post-release from asci, forms blastospores. Stalk cells are present, attached to asci, variable in shape and size, 12.4–14.8 – 17.3 × 11.1–14 – 16.9 μm.

Culture characteristics and physiological properties.

Colonies on the yeast morphology ( YM) agar, after 21 days at 20 ° C, are butyrous, smooth, slightly raised, with an even margin, creamy pink to pale pink colour (Fig. 3 E, F ); in a liquid yeast morphology medium after 6 days at 20 ° C, the cells are ovoid to ellipsoidal, 2.5 – 9.9 × 5 – 9.9 μm, sometimes with buds; sometimes large single cells up to 16 μm (Fig. 4 F ); after 14 days at 20 ° C, they form a sediment. Fermentation is absent. The assimilation of carbon compounds: d-glucose, sucrose, melezitose, d-xylose, cellobiose, glycerol, soluble starch, d-mannitol, and d-glucitol is positive. The assimilation of salicin and succinic acid assimilation is weak. Other carbon sources: maltose, lactose, raffinose, l-arabinose, inulin, trehalose, myo - inositol, melibiose, erythritol, rhamnose, galactose, ethanol, methanol, sorbose, d-arabinose, ribitol, lactate, d-ribose, xylitol, d-glukosamine, n-acetyl-d-glucosamine and citrate are not assimilated. The assimilation of nitrate, nitrite and l-lysine is positive; assimilation of ethylamine, creatinine and n-acetyl-d-glucosamine is negative. The urease reaction is positive; the diazonium blue B reaction is negative; the production of starch-like polysaccharide is positive. Growth on a vitamin-free medium is weak. Growth at 25 ° C on yeast-peptone-dextrose agar is positive; at 28 ° C negative.

Additional specimens examined.

• Slovakia; the Žiarska valley of the river Smrečianka ; 1050 m a. s. l.; on the leaves of the host shrubs Alnus alnobetula along a touristic trail; 31. 7. 2015; leg. K. Bacigálová; BU 095 ( SAV) / ( CCY 58-9 - 2 ) • ibid.; 26. 7. 2013; leg. K. Bacigálová, J. Petrýdesová; BU TA 4 ( SAV) • ibid, 16. 8. 2022; leg. K. Bacigálová, G. Kozárová; BU TA 8 ( SAV) • ibid.; 17. 8. 2023; leg. K. Bacigálová, G. Kozárová; BU TA 9 ( SAV) .

Note.

According to our phylogenetic analysis, Taphrina viridis is related to T. sadebeckii and T. epiphylla . The symptoms of disease induced by these three species are similar: they cause yellow or grey lesions on alder leaves, which, in the case of T. epiphylla infections, may lead to the formation of witches’ brooms branch deformations (Table 2 ). In the field, T. viridis can be recognised by the more greenish and less greyish tinge of the lesions. Our data suggest that this species grows strictly on Alnus alnobetula , and no other Taphrina species has been recorded on this alder host tree. Under a microscope, T. viridis is characterised by a unique combination of long-narrow stalk cells (on avg. longer than 10 μm and narrower than 16 μm) and large ascospores (on avg. 6.5 × 4.4 μm), with post-release budding. The other Alnus - colonizing species, which has been reported with post-release budding, is T. tosquinetii ; however it has distinctly smaller ascospores (Suppl. material 1). The physiological profile of Taphrina viridis is very similar to that of the closely related T. sadebeckii . Both species utilise a broad range of carbon and nitrogen sources (see the species profiles), but T. viridis differs from T. sadebeckii in its ability to assimilate nitrite, its weak ability to assimilate salicin and succinic acid, and its inability to utilise inulin, xylitol and citrate.

Figures

Figure 3. Macromorphological aspects of Taphrina viridis A – D field appearance and symptomatic E, F yeast cultures on yeast-peptone-dextrose agar (YPD).

Figure 4. Micromorphological aspects of Taphrina viridis A, B subcuticullar vegetative mycelium C, D asci with ascospores and stalk cells E ascospores with post-release budding F yeast cells grown on yeast morphology medium at 20 ° C for 6 days. Scale bars: 20 µm.