11 June 2022

What controls nitrogen fixation by cyanobacteria on mosses?


Micrograph of Cyanobacteria (bright red) on and around leaves of the widespread moss Pleurozium schreberi (bright green) collected in boreal forests, N Sweden. Credit: K. Rousk

Did you know that most mosses are colonized by nitrogen (N)-fixing cyanobacteria? This discovery is relatively recent, which can explain the large knowledge gaps the field is facing.

- “Nonetheless, we have a good understanding of the abiotic controls (e.g. nutrient availability, temperature, humidity) of N fixation in mosses but we still do not know much about the biotic controls. Further, most research has been conducted in Northern, cold biomes where mosses are dominant and common,” says Kathrin Rousk from Section of Terrestrial Ecology, Department of Biology.

Kathrin Rousk, Department of Biology, University of Copenhagen

But how widespread, important and susceptible to environmental change N fixation is in other systems such as drylands and tropical forests is unknown.

 Mosses are colonized -epiphytically- by a range of different bacteria, including different N-fixing phyla. Yet, if and how they interact with the moss host is beyond our current knowledge. Cyanobacteria and mosses are “old” groups, they had sufficient time to establish a stable association. Yet, mosses do not provide any structures to host cyanobacteria. Why not?

In the New Phytologist Tansley Insight review Kathrin Rousk synthesizes current knowledge on the biotic and abiotic controls of N fixation in an understudied plant group -mosses- and identify key challenges on the topic.

- “I propose here that we should endeavour to position cyanobacteria-moss associations along the mutualism-parasitism continuum under varying abiotic conditions. This would finally unravel the nature of the relationship between the partners and would be a big leap in our understanding of the evolution of plant-bacteria interactions using moss-cyanobacteria associations as a model system”, Kathrin Rousk finalizes.


Link to the paper: https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.18264

About New Phytologist  

New Phytologist is a leading international journal focusing on high quality, original research across the broad spectrum of plant sciences, from intracellular processes through to global environmental change. The journal is owned by the New Phytologist Foundation, a not-for-profit organisation dedicated to the promotion of plant science. 

Tansley reviews and insights are New Phytologist's flagship review series. Initiated with the Tansley reviews in 1985, and followed by the Tansley insights in 2015, the series is intended to provide a service to the plant science community. All articles are made free to read upon publication as part of the New Phytologist Foundation's not-for-profit remit.  


TT-Assist Prof. Kathrin Rousk
Section of Terrestrial Ecology, Department of Biology
Mail: Kathrin.rousk@bio.ku.dk
Web: https://www1.bio.ku.dk/english/research/te/ecosystem-ecology/
Tel: +46 705290367

Sidsel Kretzschmer Henriksen
Science journalist
Department of Biology
Mail: sidsel.henriksen@bio.ku.dk
Tel: +45 3533 4147