Prof. Sivonen has studied toxic and bioactive compounds producing cyanobacteria since 1985.
Her previous research has shown that toxic mass occurrences of cyanobacteria are common in Finnish lakes and in the Baltic Sea. Neurotoxic and hepatotoxic cyanobacteria are found in freshwater bodies while only hepatotoxic blooms occur in the Baltic Sea. Many new toxins variant were described. The producers and the conditions for toxin production were investigated. During the research the culture collection of cyanobacteria has grown to contain over 1000 cyanobacteria. It provides model strains to study cyanobacterial phylogeny, physiology or ecology. It also serve as a renewable source for discoveries of bioactive compounds and their biosynthesis through genome mining. Molecular tools were developed to detect toxins and odorous metabolites producing cyanobacteria based on discovered biosynthetic genes. Cyanobacteria are a prolific source of novel bioactive compounds containing anticancer, antifungal, and antibacterial activities. We have described number of new compounds and compound variants and shown how commonly they are produced. We have sequenced several full and draft genomes of cyanobacteria and by genome mining confirmed cyanobacteria to be one of the major bacterial lineages containing high number of non-ribosomal as well as ribosomal biosynthetic gene clusters. The new compounds and compound variants recently described include non-ribosomally produced anabaenolysins, nostopeptolides, hassallidins, scytophycins, aeruginosins, spumigins and ribosomally produced cyanobactins. This research has also led to discovery of novel biosynthetic gene clusters and enzymes. We have also used the full genome sequences to study response of cyanobacteria to environmental stimulate at transcriptome and proteome level. Cyanobacteria are important sinks of carbon but our recent findings show that Baltic Sea Nodularia spumigena strains were able to use phosphonates as alternative phosphorous source and simultaneously produce methane – the very potent greenhouse gas.
Prof. Sivonen has published 217 articles in peer-reviewed journals. Her H-index is 60 and she has 10715 citations (without self-citations, Web of Science 5.11.2018).