Production of Paralytic Shellfish Toxins (PSTs) in Toxic Alexandrium catenella is Intertwined with Photosynthesis and Energy Production

Toxins (Basel). 2020 Jul 27;12(8):477. doi: 10.3390/toxins12080477.


To investigate the mechanism for the production of paralytic shellfish toxins (PST) in toxic dinoflagellates, with a 2D-gel based approach, we had made two sets of proteomic comparisons: (a) between a toxic Alexandrium catenella (AC-T) and a phylogenetically closely related non-toxic strain (AC-N), (b) between toxic AC-T grown in a medium with 10% normal amount of phosphate (AC-T-10%P) known to induce higher toxicity and AC-T grown in normal medium. We found that photosynthesis and energy production related proteins were up-regulated in AC-T when compared to AC-N. However, the same group of proteins was down-regulated in AC-T-10%P when compared to normal AC-T. Examining the relationship of photosynthesis and toxin content of AC-T upon continuous photoperiod experiment revealed that while growth and associated toxin content increased after 8 days of continuous light, toxin content maintained constant when cells were shifted from continuous light to continuous dark for 3 days. This emphasized the cruciality of light availability on toxin biosynthesis in AC-T, while another light-independent mechanism may be responsible for higher toxicity in AC-T-10%P compared to normal AC-T. Taken all together, it is believed that the interplay between "illumination", "photosynthesis", "phosphate availability", and "toxin production" is much more complicated than what we had previously anticipated.

Keywords: Alexandrium catenella; PSTs; light availability; paralytic shellfish toxins; phosphate limitation; proteomics.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dinoflagellida / genetics
  • Dinoflagellida / growth & development
  • Dinoflagellida / metabolism*
  • Energy Metabolism*
  • Light
  • Marine Toxins / metabolism*
  • Phosphates / metabolism
  • Photoperiod
  • Photosynthesis*
  • Phylogeny
  • Proteomics
  • Shellfish Poisoning


  • Marine Toxins
  • Phosphates