First detection of benthic cyanobacteria in Lake Baikal producing paralytic shellfish toxins

• First report on PST producing benthic cyanobacteria in Lake Baikal is presented.
• Cyanobacterial bloom was detected on diverse substrates, including endemic sponges.
• Microscopic examination found that Tolypothrix distorta dominated in the fouling.
• PCR and sequencing detected sxtA gene involved in saxitoxin biosynthesis.
• Eight PST variants were identified using a MALDI mass spectrometer.

Cyanobacteria were screened from the surface of diseased sponges, stone and bedrock in Lake Baikal for the presence of saxitoxin using enzyme-linked immunosorbent assay. In sequel, eight paralytic shellfish toxin (PST) variants were identified using a MALDI mass spectrometry. Microscopic examination found that Tolypothrix distorta dominated in the biofouling samples. PCR and sequencing detected sxtA gene involved in saxitoxin biosynthesis, thereby providing evidence of the PST producing potential of Baikal cyanobacterial communities inhabiting different substrates.