Cyanotoxins, such as hepatotoxic microcystins (MCs), and many other biologically active metabolites harmful to living organisms, including humans, are frequently produced by bloom-forming cyanobacteria.
More...Cyanotoxins, such as hepatotoxic microcystins (MCs), and many other biologically active metabolites harmful to living organisms, including humans, are frequently produced by bloom-forming cyanobacteria. This research presents a study on the biodegradation of MC-RR, MC-LR, and MC-LF after a 9-day incubation with a community of microorganisms associated with the macrophyte Spirodela polyrhiza. S. polyrhiza turions were cultured for three weeks in Steinberg medium to facilitate the development of plant microbiota both on the plants and in the medium. Subsequently, S. polyrhiza was removed, and the medium containing the microbiota associated with S. polyrhiza, was supplemented and diluted with pure Steinberg medium along with different MCs (MC-RR, MC-LR and MC-LF), each at a final concentration of 1,000 ng/ml for each MC. The experimental variants were incubated for the following nine days. After nine-day incubation period, the microbiota were collected by centrifugation, and then subjected to total DNA isolation and NGS seqencing. NGS-based microbiota profiling of these consortia showed that there were no statistically significant differences in the qualitative structure of bacterial communities in particular experimental variants after exposure to MCs. In all variants, Proteobacteria, which are well-known MC-degraders, predominated, comprising more than 80% of the total relative bacterial abundance. Bacteroida and Firmicutes reached 7,6 to 14,9% and 2 to 6,4%, respectively. The present findings indicate that the microbiota associated with S. polyrhiza can biodegrade MC-RR and MC-LR variants. The potential of the microbiota of aquatic plants to biodegrade MCs can be environmentally relevant, and further studies in this field are required.
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