Format: ORAL

Danillo Oliveira Alvarenga, Lina vila Clasen, Rune Fromm Andersen, Kathrin Rousk

¹Department of Biology, University of Copenhagen, Denmark ²Center for Volatile Interactions, University of Copenhagen, Denmark

Cyanobacteria are oxygenic photoautotrophs that are widely known for releasing potent toxins in water bodies, contributing to global oxygen production and playing an important part in the evolution of life on the planet. Nevertheless, nitrogen-fixing cyanobacteria also perform a vital ecological role in the nitrogen cycle of several aquatic and terrestrial ecosystems, either as free-living organisms or in symbiotic relationships. Several plants from tropical, temperate and boreal environments were shown to recruit cyanobacteria as epiphytic symbionts when going through nitrogen starvation. This includes mosses, non-vascular plants that are usually found in moist and shaded areas. These bryophytes can be responsible for up to 100% of primary production in some pristine northern ecosystems, in which 50% of the nitrogen input may derive from mosscyanobacteria associations. Mosscyanobacteria interactions have consequences on a global scale, since northern environments sequester 20% of all the carbon generated by forests in the world and stock at least 32% of global terrestrial carbon. Nevertheless, few is known about how mosses can influence the physiology and nitrogen-fixing activities of these microorganisms. Information is also lacking about the importance and dynamics of mosscyanobacteria interactions in tropical ecosystems and how they will be directly or indirectly affected by climate change. In this presentation, I will explore advances on the molecular aspects of ecological interactions between mosses and cyanobacteria in northern and tropical ecosystems. Our results suggest that mosses from different environments are potentially capable of manipulating the morphophysiology of cyanobionts to increase their N fixation rates, but without necessarily giving cyanobacteria something in return.