New paper on terrestrial cyanobacteria - an interesting biocrust in alkaline grasslands

Our paper about terrestrial cyanobacteria has recently been published in Algal Research. The main authors of the paper are Milán Riba, Gábor Vasas and their colleagues who explored the peptide metabolite patterns of Nostoc-like strains.

The citation of the paper is

Riba, M., Kiss, A., Gonda, S., Parizsa, P., Deák, B., Török, P., Valkó, O., Vasas, G. (2020): Chemotyping of terrestrial Nostoc-like isolates from alkali grassland areas by non-targeted peptide analysis. Algal Research 46: 101798. doi: 10.1016/j.algal.2020.101798 [IF2018: 3.723]

Please click here to download the paper. 

Why are Nostoc species important? Nostoc is a genus of nitrogen-fixing cyanobacteria. They play a role in the maintenance of soil fertility and are used as green manure in many countries. In tropical and subtropical regions, mass presence of Nostoc species is typical in flooded rice paddies. They significantly increase soil fertility and rice yields. Nostoc species are one of the most common photosynthetic partners in symbiotic interactions; symbiotic Nostoc strains can occur in liverwort, hornwort, ferns, cycads, angiosperms and lichens.

Nostoc biocrust (black formations) in an open alkaline grassland.

The reason why we are particularly interested in Nostoc is that they form biocrust in continental alkaline grasslands. In Europe, these habitats cover approx. 200 000 ha, which is almost entirely (>98%) located in Hungary. Alkaline habitats are included in the Natura 2000 network as habitats of special community interest (*1530, Pannonic salt steppes and marshes). Colonies of Nostoc species appear at the beginning of spring, when the soil surface is flooded with water. Swollen colonies form mucous layers which then dry out during summer. In our former paper (Sonkoly et al. 2017) we tested the effect of Nostoc on the germination of plant of alkaline grasslands. We used field-collected Nostoc colonies to prepare a cell-free water extract, and treatments (watering with Nostoc extract and watering with tap water) were tested seeds of nine alkaline grassland species. Our results suggest that the presence of Nostoc colonies might affect the establishment of grassland species. We found that the effect of the Nostoc extract was species-specific, which suggests that Nostoc species may be an indirect driver of the interspecific competition between grassland plants.

The recently published Riba et al. (2020) paper takes a new step towards the better understanding of the diversity of Nostoc, important biocrusts of alkaline grasslands. We demonstrated the peptide metabolite-producing ability of terrestrial nitrogen-fixing cyanobacteria from different sites of the alkaline habitats of Hungary. The isolated Nostoc-like strains could be classified into different chemotype groups based on their metabolic pattern. A total of 41 peptide-type metabolites were identified which belonged to 4 different peptide families.

Open alkaline swards are typical habitats of Nostoc.