Prasiola Meneghini.

Veselá, Veronika, Malavasi, Veronica & Škaloud, Pavel, 2024, A synopsis of green-algal lichen symbionts with an emphasis on their free-living lifestyle, Phycologia 63 (3), pp. 317-338 : 325

Prasiola Meneghini.

Prasiola is a cosmopolitan genus, which can be found in a wide range of habitats ( Broady 1989; Heesch et al. 2012; Rindi et al. 2007) Unlike its relatives, Prasiola forms macroscopic, usually monostromatic thalli of various shapes (ribbon-shaped/sheet-like blades; Fig. 10 ) and sizes. The cells, arranged in groups of four, contain axial, asteroid chloroplast with one centrally-located pyrenoid. Prasiola reproduces asexually by thallus fragmentation or sexually oogamously (Ettl & Gärtner 2013).

Two of the 34 described species ( Guiry & Guiry 2022), P. borealis and P. delicata , enter lichen-like symbiosis with the bipolarly distributed fungus Mastodia tessellata ( Verrucariaceae ; Garrido-Benavent et al. 2018). This unusual association, sometimes referred to as ‘borderline-lichen’, gives rise to a thallus, which is formed mainly by the algal partner, whose outer appearance is not changed, but its inner structure is significantly altered ( Kováčik & Pereira 2001).

Free-living P. borealis and P. delicata specimens have been collected from coastal rock in Alaska ( Garrido-Benavent et al. 2017). In addition, free-living P. delicata was observed in the intertidal of Hokkaido, Japan ( Sutherland et al. 2016) and in Kamchatka, Russia ( Klochkova et al. 2017).

Figures

Figs 1–18. Lichen photobiont genera (including nonlichenized species) belonging to classes Trebouxiophyceae and Chlorophyceae. Fig. 1. Asterochloris lobophora. Fig. 10. Prasiola crispa. Fig. 2. Myrmecia incisa. Fig. 11. Pseudochlorella pringsheimii. Fig. 3. Trebouxia impressa. Fig. 12. Stichococcus sp. Fig. 4. Vulcanochloris symbiontica. Fig. 13. Auxenochlorella protothecoides. Fig. 5. Chloroidium saccharophilum. Fig. 14. Apatococcus sp. Fig. 6. Jaagichlorella luteoviridis. Fig. 15. Leptosira sp. Fig. 7. Coccomyxa sp. Fig. 16. Symbiochloris tschermakiae. Fig. 8. Elliptochloris subsphaerica. Fig. 17. Uvulifera verrucariae (Lorenz 2016). Fig. 9. Diplosphaera chodatii. Fig. 18. Bracteacoccus. sp. Scale bars: 10 μm (Figs 1-9, 11-18), 200 μm (Fig. 10).