title: Physiological and biochemical defense reactions of Vicia faba L.-Rhizobium symbiosis face to chronic exposure to cyanobacterial bloom extract containing microcystins.
abstract: The presence of cyanotoxins, mainly microcystins (MCs), in surface freshwater represents a serious health risk to aquatic organisms living in the water body, as well as terrestrial animals and plants that are in contact with contaminated water. Consequently, the use of MCs contaminated water for irrigation represents a hazard for cultivated plants and could induce severe economical losses due to crops' yield reduction. The experimental approach undertaken in this work was exposing Vicia faba seedlings (inoculated with a Rhizobium strain resistant to MCs), to water supplemented with cyanobacterial crude extract containing total microcystins at a concentration of 50 and 100 μg/L (environmental relevant concentrations of MCs dissolved in the raw irrigation water from Lalla Takerkoust Lake-Marrakesh region). After chronic MCs exposure (2 months), biological and physiological parameters (plant growth, nitrogen uptake, mineral assimilation, and oxidative defense mechanisms) were evaluated. The results obtained showed evidence that chronic exposure to cyanobacterial bloom extract containing MCs strongly affected the physiological and biological plants activities; reduction of dry matter, photosynthetic activity, nodule number, and nitrogen assimilation. At the same time, an increase of oxidative stress was observed, as deduced from a significant increase of the activities of peroxidase, catalase, polyphenoloxidase, and phenylalanine ammonia lyase in leaves, roots, and nodules of faba bean plants exposed to cyanotoxins, especially at 100 μg/L of MCs. This experimentation constitutes a simulation of the situation related to cyanotoxins chronic exposure of seedlings-plants via the contaminated irrigation water. For this reason, once should take into consideration the possibility of contamination of agricultural crops and the quality of irrigation water should be by the way monitored for cyanotoxins biohazard.
authors: Laboratory of Biology and Biotechnology of Microorganisms, Environmental Microbiology and Toxicology Unit, Faculty of Sciences Semlalia, Cadi Ayyad University, PO Box 2390, Marrakech, Morocco.
authors: Majida
authors: M
authors: Lahrouni
authors: Khalid
authors: K
authors: Oufdou
authors: Fatima
authors: F
authors: El Khalloufi
authors: Mohamed
authors: M
authors: Baz
authors: Alejandro
authors: A
authors: Lafuente
authors: Mohammed
authors: M
authors: Dary
authors: Eloisa
authors: E
authors: Pajuelo
authors: Brahim
authors: B
authors: Oudra
mesh_terms: D002374:Catalase / Q000378:metabolism; D004156:Catechol Oxidase / Q000378:metabolism; D045424:Complex Mixtures / Q000494:pharmacology*; D000458:Cyanobacteria; D052998:Microcystins / Q000494:pharmacology*; D009195:Peroxidase / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D012231:Rhizobium / Q000187:drug effects* / Q000502:physiology; D013559:Symbiosis / Q000187:drug effects*; D031306:Vicia / Q000187:drug effects* / Q000502:physiology
chemical_list: D045424:Complex Mixtures; D052998:Microcystins; D010636:Phenols; D004156:Catechol Oxidase; D002374:Catalase; D009195:Peroxidase; D010650:Phenylalanine Ammonia-Lyase