Halotolerance in Lichens: Symbiotic Coalition Against Salt Stress

• Main Authors: Delmail, David, Grube, Martin, Parrot, Delphine, Cook-Moreau, Jeanne, Boustie, Joël, Labrousse, Pascal, Tomasi, Sophie
• Other Authors: Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut für Pflanzenwissenschaften Karl-Franzens, Karl-Franzens-Universität Graz, Biomolécules Thérapies anti-tumorales (EA4021), Université de Limoges (UNILIM)-Génomique, Environnement, Immunité, Santé, Thérapeutique (GEIST FR CNRS 3503), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM)
• Format: Book Part
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; environment/Symbiosis; Antarc*; Antarctica
• Online Access: https://univ-rennes.hal.science/hal-00834238; https://doi.org/10.1007/978-1-4614-4747-4_4

International audience Lichens are among the most conspicuous and ubiquitous symbiosis on this planet. They are highly adapted to terrestrial habitats of all climatic zones including the most hostile environments on Earth, such as high altitudes in the Himalayas or the cold deserts of Antarctica. Among the extreme habitats are the littoral (or intertidal) zones of coasts. In this chapter, we present an overview of the current knowledge about the halotolerance mechanisms in lichens. Halotolerant organisms generally accumulate osmotically active solutes to cope with increasing external salinity. In intertidal lichens, mannitol could play an important role in osmoregulation. Epilichenic bacterial colonies may be also involved in limiting lichen nutrient imbalance by producing osmoprotective compounds and storing high ionic concentrations. In addition, the comparison with related inland species suggests that morphological adaptations could also be involved in adaptation to increased salt levels. Maritime species often have strongly conglutinated hyphae and small or no intercellular spaces in their thalli. So far, little genetic information exists about the genes involved in halotolerance and their regulation. Comparison of forthcoming genomic information from lichen fungi with those of other halotolerant fungi will soon help to change the picture and reveal genetic adaptations to saline environments.