Beatriz Fernández-Marín1,2, Marina López-Pozo1, Alicia V Perera-Castro3, Miren Irati Arzac1, Ana Sáenz-Ceniceros1, Claudia Colesie4, Asunción De Los Ríos5, Leo G Sancho6, Ana Pintado6, José M Laza7, Sergio Pérez-Ortega8, José I García-Plazaola1. 1. Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena sn, 48940 Leioa, Spain. 2. Department of Botany, Ecology and Physiology, University of La Laguna (ULL), 38200 La Laguna, Canarias, Spain. 3. Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears (UIB) - Instituto de Investigaciones Agroambientales y de Economía del Agua (INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain. 4. Global Change Institute, School of GeoSciences, University of Edinburgh, Alexander Crum Brown Road, Edinburgh EH9 3FF, UK. 5. Museo Nacional de Ciencias Naturales (MNCN-CSIC), Serrano 115 dpdo, 28006 Madrid, Spain. 6. Botany Section, Fac. Farmacia, Universidad Complutense, 28040 Madrid, Spain. 7. Laboratory of Macromolecular Chemistry (Labquimac), Department of Physical Chemistry, University of the Basque Country (UPV/EHU), Barrio Sarriena sn, 48940 Leioa, Spain. 8. Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014 Madrid, Spain.
Abstract
BACKGROUND AND AIMS: Lichens represent a symbiotic relationship between at least one fungal and one photosynthetic partner. The association between the lichen-forming fungus Mastodia tessellata (Verrucariaceae) and different species of Prasiola (Trebouxiophyceae) has an amphipolar distribution and represents a unique case study for the understanding of lichen symbiosis because of the macroalgal nature of the photobiont, the flexibility of the symbiotic interaction and the co-existence of free-living and lichenized forms in the same microenvironment. In this context, we aimed to (1) characterize the photosynthetic performance of co-occurring populations of free-living and lichenized Prasiola and (2) assess the effect of the symbiosis on water relations in Prasiola, including its tolerance of desiccation and its survival and performance under sub-zero temperatures. METHODS: Photochemical responses to irradiance, desiccation and freezing temperature and pressure-volume curves of co-existing free-living and lichenized Prasiola thalli were measured in situ in Livingston Island (Maritime Antarctica). Analyses of photosynthetic pigment, glass transition and ice nucleation temperatures, surface hydrophobicity extent and molecular analyses were conducted in the laboratory. KEY RESULTS: Free-living and lichenized forms of Prasiola were identified as two different species: P. crispa and Prasiola sp., respectively. While lichenization appears to have no effect on the photochemical performance of the alga or its tolerance of desiccation (in the short term), the symbiotic lifestyle involves (1) changes in water relations, (2) a considerable decrease in the net carbon balance and (3) enhanced freezing tolerance. CONCLUSIONS: Our results support improved tolerance of sub-zero temperature as the main benefit of lichenization for the photobiont, but highlight that lichenization represents a delicate equilibrium between a mutualistic and a less reciprocal relationship. In a warmer climate scenario, the spread of the free-living Prasiola to the detriment of the lichen form would be likely, with unknown consequences for Maritime Antarctic ecosystems.
BACKGROUND AND AIMS: Lichens represent a symbiotic relationship between at least one fungal and one photosynthetic partner. The association between the lichen-forming fungus Mastodia tessellata (Verrucariaceae) and different species of Prasiola (Trebouxiophyceae) has an amphipolar distribution and represents a unique case study for the understanding of lichen symbiosis because of the macroalgal nature of the photobiont, the flexibility of the symbiotic interaction and the co-existence of free-living and lichenized forms in the same microenvironment. In this context, we aimed to (1) characterize the photosynthetic performance of co-occurring populations of free-living and lichenized Prasiola and (2) assess the effect of the symbiosis on water relations in Prasiola, including its tolerance of desiccation and its survival and performance under sub-zero temperatures. METHODS: Photochemical responses to irradiance, desiccation and freezing temperature and pressure-volume curves of co-existing free-living and lichenized Prasiola thalli were measured in situ in Livingston Island (Maritime Antarctica). Analyses of photosynthetic pigment, glass transition and ice nucleation temperatures, surface hydrophobicity extent and molecular analyses were conducted in the laboratory. KEY RESULTS: Free-living and lichenized forms of Prasiola were identified as two different species: P. crispa and Prasiola sp., respectively. While lichenization appears to have no effect on the photochemical performance of the alga or its tolerance of desiccation (in the short term), the symbiotic lifestyle involves (1) changes in water relations, (2) a considerable decrease in the net carbon balance and (3) enhanced freezing tolerance. CONCLUSIONS: Our results support improved tolerance of sub-zero temperature as the main benefit of lichenization for the photobiont, but highlight that lichenization represents a delicate equilibrium between a mutualistic and a less reciprocal relationship. In a warmer climate scenario, the spread of the free-living Prasiola to the detriment of the lichen form would be likely, with unknown consequences for Maritime Antarctic ecosystems.
Authors: M Bacior; H Harańczyk; P Nowak; P Kijak; M Marzec; J Fitas; M A Olech Journal: Colloids Surf B Biointerfaces Date: 2018-10-26 Impact factor: 5.268
Authors: Leopoldo G Sancho; Ana Pintado; Francisco Navarro; Miguel Ramos; Miguel Angel De Pablo; Jose Manuel Blanquer; Jose Raggio; Fernando Valladares; Thomas George Allan Green Journal: Sci Rep Date: 2017-07-24 Impact factor: 4.379