Attempted isolation and success in the culturing of a broad spectrum of lichen-forming and lichenicolous fungi

• Published in: The New phytologist 1995-06, Vol.130 (2), p.267-297
• Main Authors: Crittenden, P.D, David, J.C, Hawksworth, D.L, Campbell, F.S
• Format: Article
• Language: English
• Subjects: Ascospores; axenic cultures; Biological and medical sciences; Biological taxonomies; culture collections; culture media; culture techniques; cultures; death; descriptions; Fundamental and applied biological sciences. Psychology; Fungal spores; Fungi; germfree state; growth; isolation; isolation success; lichenicolous fungi; Lichenology; Lichens; Lichen‐forming fungi; methodology; mortality; mycobionts; Mycology; origin; Parasitism and symbiosis; Plant physiology and development; plant tissues; species; specimen handling; specimens; Spore discharge; symbionts; Symbiosis; Taxa; Thallus
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.1995.tb03048.x

Isolation into pure culture was attempted on 1183 species (2238 specimens) of lichen-forming and lichenicolous fungi from diverse ecosystems and systematic groups (covering 14 ascomycete orders, 77 families and 280 genera), in 20 countries. Four hundred and ninety three species (42%) were successfully isolated either from ascospores (or basidiospores, or conidia) or photobiont-free fragments from thallus macerates. Of the total number of isolation attempts from ascospores (1609) and thallus fragments (719), 30% and 32% respectively were successful. The reasons for failure to isolate from ascospores were: ascospores did not germinate (43%) > ascospores were not discharged (30%) > ascospores germinated but growth was not sustained (19%) > discharged spores were heavily contaminated (8%). 59% of isolation failures with fragments were due to lack of growth and 41% were due to contamination. The orders from which mycobionts were most readily isolated were the Ostropales (70% of species attempted were isolated), Dothideales (63%), Pertusariales (53%) and Lecanorales (45%); those orders least readily yielding isolates were Verrucariales (10%), Gyalectales (20%), Arthoniales (30%), Lichinales (29%) and Peltigerales (27%). Members of the Lecanorales comprised c. 60% of species collected of which Porpidiaceae (80% of species successfully isolated), Cladoniaceae (69%), Lecideaceae (67%), Rhizocarpaceae (62%), Umbilicariaceae (60%), Ramalinaceae (60%) and Lecanoraceae (54%) were comparatively successful families and Alectoriaceae (18%), Catillariaceae (8%), Pannariaceae (8%) Collemataceae (7%), and Micareaceae (6%) were least successful. Of those species containing a cyanobacterium (either as the primary photobiont or in cephalodia), only 22% yielded isolates compared with 46% and 43% of lichens containing only a chlorococcoid photobiont or Trentepohlia, respectively. Success was even lower (17%) in species containing a cyanobacterium as the primary photobiont. Among non-cyanobacterial lichens, isolation of mycobionts was achieved in 56% of fruticose species collected compared with 43% and 40% for crustose/squamulose and foliose taxa respectively. Mycobionts of fruticose lichens cultured particularly readily from fragments, with 56% of green algal species to which this method was applied coming into culture compared to 37% of non-cyanobacterial foliose species. Lichenicolous fungi cultured less readily, with only 31% of species yielding isolates. In many species viabi