Secondary photobiont
secondary photobiont (noun, pl. secondary photobionts) – literally: the second photosynthetic partner that a lichen symbiosis acquires; in a more general sense: a less dominant population of photobiont cells that is additionally present in a lichen thallus, typically a population of cyanobacteria in a lichen thallus otherwise dominated by green algal cells (a chlorolichen with additional cyanobionts). This is quite common in some lichen genera like Stereocaulon or Peltigera, where the secondary photobiont is typically restricted to specialized structures called cephalodia. However, some lichens are also capable to establish a photosymbiodeme, i. e., morphologically identical or different thalli with either cyanobacteria or green algae as primary photobiont. Also, some lichen mycobionts may be primarily associated with one particular photobiont genus, but occasionally different photobiont cells occur as accessory photobiont. Some chlorolichens form loose associations with cyanobacteria as accessory photobiont. These cyanobacteria are not regularly part of the symbiosis and they are therefore not secondary photobionts. Instead the phenomenon is known as cyanotrophy. Related terms: photobiont, primary photobiont, accessory photobiont, cyanotrophy, photosymbiodeme.
This page is part of the LIAS Glossary. It is closely interlinked with the other LIAS projects: LIAS • LIAS light • LIAS names • LIAS gtm. See also Cooperating Websites
Many pages in the LIAS Glossary is in need of further revisions. Please contribute. Criticism as well as collaboration is welcome!
