Jouko Rikkinen - Plant Biology

Multidisciplinary Studies on the Diversity, Ecology and Evolution of Cyanobacteria, Eukaryotic Phototrophs and Fungi

Professor Jouko Rikkinen

Cyanobacteria, fungi and eukaryotic phototrophs (algae and plants) have affected each other profoundly during the course of evolution. The ultimate examples of this are the chloroplasts of plants, which once evolved from cyanobacterial ancestors. Among the earliest fungal symbioses were primitive lichens, presumably those with cyanobacterial photobionts. Littoral habitats along ancient shorelines brought a range of free-living cyanobacteria, green algae and fungi together under conditions where there were good opportunities for new symbiotic interactions. Lichens probably developed long before the initial evolution of mycorrhizal symbioses, the subsequent rise of vascular plants and later radiations of parasitic and saprophytic fungi. Accordingly, some modern lichens may preserve biological features from very early stages of terrestrial evolution.

Even today lichen symbioses represent a major way of life among the Fungi. Almost one-fifth of all known fungal species are lichenized and within the ascomycetes about two-fifths of known species are lichen-forming. The morphological and physiological characteristics of lichen symbioses are highly specialized and involve intricate connections between the symbionts. As lichens include primary as well as secondary producers, and have their own carbon cycles, they resemble miniature ecosystems rather than individuals or populations. Their symbiotic nature is not limited to the thallus level biology of individual lichen species - symbiotic processes also shape lichen communities.

Modern lichenology is a multidisciplinary discourse focusing on organisms and processes that are symbiotic by definition. Our research unit focuses on the diversity, ecology and evolution of symbiotic entities, with primary interest on lichen-forming organisms. However, also other multidisciplinary topics are pursued. We recognize symbiosis as a major source of evolutionary novelty and hope to contribute significantly to the mainstream of ecological and evolutionary innovation.

Our ongoing research projects can be grouped under five loose headings. Please check the attached pdf-files for more information.

Symbiont Specificity in Lichen and Bryophyte Symbioses >> Pdf
Paleobiology of Cryptogams Preserved in Amber >> Pdf
Systematics and Ecology of Resinicolous Fungi >> Pdf
Foristics and Ecology of Terrestrial Cryptogams >> Pdf
Diversity and Ecological Significance of African Mahoganies >> Pdf