Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017
Erindi/veggspjald / Talk/poster V15
Höfundar / Authors: Denis Warshan (1), Josh L. Espinoza (2, 3), RhonaK.Stuart (4), R. Alexander Richter (2, 3), Nicole Shapiro (5), Tanja Woyke (5), Charles Ansong (6), Heather M. Brewer (6), Christopher L. Dupont (2), Philip D. Weyman (3), Ulla Rasmussen (1)
Starfsvettvangur / Affiliations: 1. Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden, 2. Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, 3. Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, CA, 4. Lawrence Livermore National Laboratory, Livermore, CA, 5. US Department of Energy Joint Genome Institute, Walnut Creek, CA, 6. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA
Kynnir / Presenter: Denis Warshan
The nitrogen cycling in boreal forest ecosystems is largely determined by a symbiotic association between feather mosses (Pleurozium schreberi and Hylocomium splendens) and diazotrophic cyanobacteria that fix majority of nitrogen flowing into boreal ecosystems (1). Because nitrogen is often limiting in boreal forests, the interaction between the cyanobacteria and the mosses greatly affects the productivity of this ecosystem that makes up almost 30% of Earth’s forested land (2-3). Despite its significance, little is known about the cyanobacterial gene repertoire and regulatory rewiring needed for the establishment and maintenance of the symbiosis. To determine gene acquisitions and regulatory changes allowing cyanobacteria to form and maintain this symbiosis, we compared genomically closely related symbiotic-competent and -incompetent Nostoc strains using a proteogenomics approach and an experimental set up allowing for controlled chemical and physical contact between partners. Thirty-two gene families were found only in the genomes of symbiotic strains, including some never before associated with cyanobacterial symbiosis. We identified conserved orthologs that were differentially expressed in symbiotic strains, including protein families involved in chemotaxis and motility, NO regulation, sulfate/phosphate transport, and glycosyl-modifying and oxidative stress-mediating exoenzymes. The physical moss–cyanobacteria epiphytic symbiosis is distinct from other cyanobacteria–plant symbioses, with Nostoc retaining motility, and lacking modulation of N2-fixation, photosynthesis, GS-GOGAT cycle and heterocyst formation. The results expand our knowledge base of plant–cyanobacterial symbioses, provide a model of information and material exchange in this ecologically significant symbiosis, and suggest new currencies, namely nitric oxide and aliphatic sulfonates, may be involved in establishing and maintaining the cyanobacteria–feathermoss symbiosis.