Cyanobacterial toxins: A short review on phytotoxic effect in an aquatic environment

Cyanobacteria are photosynthetic prokaryotes which frequently form blooms in eutrophic water bodies. Some species of cyanobacteria are able to produce toxins (cyanotoxins) that can cause aquatic environment and diverse organisms living there to be at a serious risk. One of the more serious impacts of eutrophication on aquatic ecosystems is the disappearance of submerged macrophytes and the shift to a phytoplankton-dominated state. Hence, cyanobacterial blooms may be of significant negative ecological impact. This may represent a sanitary risk due to toxin bioaccumulation and biotransfer through the food chain. So, with the increasing number of new researches made on this subject, we propose this paper to review clearly many recent and original reports that have demonstrated the effects of cyanotoxins on some biological and physiological pathways in different aquatic plants.Keywords: Cyanotoxins, microcystins, aquatic plants, eco-physiological, sanitary risk

CyanoHAB Occurrence and Water Irrigation Cyanotoxin Contamination: Ecological Impacts and Potential Health Risks

The world-wide occurrence of harmful cyanobacteria blooms “CyanoHAB” in fresh and brackish waters creates problems for all life forms. During CyanoHAB events, toxic cyanobacteria produce cyanotoxins at high levels that can cause chronic and sub-chronic toxicities to animals, plants and humans. Cyanotoxicity in eukaryotes has been mainly focused on animals, but during these last years, data, related to cyanotoxin (mainly microcystins, MCs) impact on both aquatic and terrestrials crop plants irrigated by water containing these toxins, have become more and more available. This last cited fact is gaining importance since plants could in a direct or indirect manner contribute to cyanotoxin transfer through the food chain, and thus constitute a potent health risk source. The use of this contaminated irrigation water can also have an economical impact which appears by a reduction of the germination rate of seeds, and alteration of the quality and the productivity of crop plants. The main objective of this work was to discuss the eventual phytotoxicity of cyanotoxins (microcystins) as the major agricultural impacts induced by the use of contaminated water for plant irrigation. These investigations confirm the harmful effects (ecological, eco-physiological, socio-economical and sanitary risk) of dissolved MCs on agricultural plants. Thus, cyanotoxin phytotoxicity strongly suggests a need for the surveillance of CyanoHAB and the monitoring of water irrigation quality as well as for drinking water