News from ‘black belt’ masters of symbiosis

Abstract

News from 'black belt' masters of symbiosisThe reputation of lichens as extremotolerant organisms is built on their occurrence in habitats where most other eukaryotes find it difficult to survive. Lichens withstand recurrent cycles of desiccation and re-wetting in their environments by reverting to a state without active signs of life during periods of drought, yet they are able to resume metabolism quickly with appropriate levels of hydration. In this stage, a substrate's conditions, including chemistry, pH level, and water availability, determine the composition of lichen species in different habitats. Their sensitivity in metabolically active stages also explains the use of lichens as finetuned bioindicators of environmental conditions.