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SANCOOP-South Africa - Norway research co-operation on climate, the environment og clean energy

Climate change - can lichens protect themselves using UV-induced melanins?

Alternative title: Klimaendring - kan laver beskytte seg med UV-induserte melaniner?

Awarded: NOK 0.23 mill.

Lichens dominate over large areas especially in dry ecosystems and in Arctic and Antarctic regions. Ecologically, lichens play key roles in both South Africa and Norway. For southern African dry areas, loss of lichens likely results in severe erosion and significant loss of nitrogen fixation capacity because lichens with cyanobacteria can take up nitrogen directly from the air. Although lichens may tolerate severe stresses, many lichen-dominated systems are among the most sensitive to climate change. Reactive oxygen species, probably involved in melanin synthesis, may have a role in pathogen defence. Several lichens in extreme habitats synthesize melanins which are dark brown pigments. Melanins in lichens are induced by UV radiation. Also in human skin melanins are induced by UV radiation. However, since dark brown lichens absorb more radiation the lichen temperatures will probably rise, an effect that may be more negative with global warming. Our main aim is to study the mechanism of UV induced melanin synthesis in lichens from both South Africa and Norway. In South Africa have enzymes which may be involved in melanin biosynthesis been characterized. A master thesis on this topic was delivered by Patrick Lusanda Matee in the end of 2015. In Norway, have the effects of UV radiation on melanin synthesis, growth, photosynthesis and spectral properties been studied. A master thesis on this topic by Dipa Paul Chowdhury was finished in June 2015. Masterstudent Tshepiso Coral Mafole from South Africa visited NMBU in August 2016 and she will deliver a master thesis in 2017.

Lichens dominate over large areas of terrestrial ecosystems, for example as components of dryland crusts and in Arctic and Antarctic regions. Ecologically, lichens play key roles in both South Africa and Norway. For southern African soil crusts, loss of l ichens likely results in severe erosion and significant losses of nitrogen fixation capacity. Although lichens may tolerate severe abiotic stresses, many lichen-dominated systems are among the most sensitive to climate change. Reactive oxygen species, pro bably involved in melanin synthesis, may have a role in pathogen defence. Several lichens in extreme habitats synthesize melanins. Studied melanins are induced by UV radiation, but they mainly protect lichens against high visible light intensity. However, they may cause lichen temperatures to rise, an effect that may be more negative with global warming. However, the nature of lichen melanins remains uncertain. Free-living fungi contain two main types of melanins, the eumelanins and the allomelanins. It h as been suggested that one major clade of lichens, the "Peltigeralean" species, synthesizes eumelanins while species in other clades synthesize allomelanins. However, no firm data is available. Our main aim is to study UV induced melanin synthesis both in Peltigeralean and non-Peltigeralean lichens from both South Africa and Norway. In South Africa lichens will be collected from sensitive habitats, in particular soil crusts and montane regions, and enzymes involved in melanin biosynthesis will be characte rized. In Norway, the effects of UV radiation on melanin synthesis, growth, photosynthesis and spectral properties will be studied. This co-operation will certainly result in new knowledge that has the potential to predict the impact of climate change on lichen communities.

Funding scheme:

SANCOOP-South Africa - Norway research co-operation on climate, the environment og clean energy

Funding Sources