Allelopatic effects of cyanobacteria extracts containing microcystins on Medicago sativa–Rhizobia symbiosis

Khalloufi, Fatima El; Oufdou, Khalid; Lahrouni, Majida; Ghazali, Issam El; Saqrane, S.; Vasconcelos, Vı́tor; Oudra, Brahim

doi:10.1016/j.ecoenv.2010.10.006

Cited by 43 publications

(34 citation statements)

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“…MCs have been associated with the inhibition of germination and growth of several agricultural and forage plants (Crush et al 2008;El Khalloufi et al 2011;Saqrane et al 2008). MCs were shown to inhibit the nodulation of fava bean (Vicia faba) and alfalfa (Medicago sativa) (El Khalloufi et al 2011;Lahrouni et al 2012). This condition may have implications in nitrogen uptake and development of leguminous plants.…”

Section: Introductionmentioning

confidence: 99%

Early physiological and biochemical responses of rice seedlings to low concentration of microcystin-LR

Azevedo¹,

Azevedo

Osório

et al. 2013

Ecotoxicology

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Microcystin-leucine and arginine (microcystin-LR) is a cyanotoxin produced by cyanobacteria like Microcystis aeruginosa, and it's considered a threat to water quality, agriculture, and human health. Rice (Oryzasativa) is a plant of great importance in human food consumption and economy, with extensive use around the world. It is therefore important to assess the possible effects of using water contaminated with microcystin-LR to irrigate rice crops, in order to ensure a safe, high quality product to consumers. In this study, 12 and 20-day-old plants were exposed during 2 or 7 days to a M. aeruginosa extract containing environmentally relevant microcystin-LR concentrations, 0.26-78 lg/L. Fresh and dry weight of roots and leaves, chlorophyll fluorescence, glutathione Stransferase and glutathione peroxidase activities, and protein identification by mass spectrometry through twodimensional gel electrophoresis from root and leaf tissues, were evaluated in order to gauge the plant's physiological condition and biochemical response after toxin exposure. Results obtained from plant biomass, chlorophyll fluorescence, and enzyme activity assays showed no significant differences between control and treatment groups. How-ever, proteomics data indicates that plants respond to M. aeruginosa extract containing environmentally relevant microcystin-LR concentrations by changing their metabolism, responding differently to different toxin concentrations. Biological processes most affected were related to protein folding and stress response, protein biosynthesis, cell signalling and gene expression regulation, and energy and carbohydrate metabolism which may denote a toxic effect induced by M. aeruginosa extract and microcystin-LR. The implications of the metabolic alterations in plant physiology and growth require further elucidation.

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Section: Introductionmentioning

confidence: 99%

Early physiological and biochemical responses of rice seedlings to low concentration of microcystin-LR

Azevedo¹,

Azevedo

Osório

et al. 2013

Ecotoxicology

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“…El Khalloufi et al (2011) evaluated the effects of different concentrations of MCs on the development of symbiosis between Medicago sativa L. and rhizobia strains and observed a reduction in growth of both the plant and the bacterial nodules. It was also found that exposure of alfalfa seeds and seedlings to concentrations of 0, 2.22, 11.12 or 22.24 mg L -1 MCs affected all stages of plant development and led to reduced root length.…”

Section: Diverse Effects Of Microcystins On Terrestrial Plantsmentioning

confidence: 99%

Phytotoxicity associated to microcystins: a review

et al. 2014

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Microcystins (MC) are the most studied toxins of cyanobacteria since they are widely distributed and account for several cases of human and animal poisoning, being potent inhibitors of the serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A). The phosphatases PP1 and PP2A are also present in plants, which may also suffer adverse effects due to the inhibition of these enzymes. In aquatic plants, biomass reduction is usually observed after absorption of cyanotoxins, which can bioaccumulate in its tissues. In terrestrial plants, the effects caused by microcystins vary from inhibition to stimulation as the individuals develop from seedling to adult, and include reduction of protein phosphatases 1 and 2A, oxidative stress, decreased photosynthetic activity and even cell apoptosis, as well as bioaccumulation in plant tissues. Thus, the irrigation of crop plants by water contaminated with microcystins is not only an economic problem but becomes a public health issue because of the possibility of food contamination, and this route of exposure requires careful monitoring by the responsible authorities.Keywords: bioaccumulation, microcystins effects, crop plants, aquatic plants. Fitotocixidade associada às microcistinas: uma revisão ResumoMicrocistinas (MC) são as toxinas de cianobactérias mais estudadas, uma vez que são amplamente distribuídas e responsáveis por vários casos de intoxicação humana e animal. São potentes inibidoras das proteínas fosfatases serina/treonina 1 (PP1) e 2A (PP2A). As fosfatases PP1 e PP2A também estão presentes em plantas, as quais podem sofrer efeitos adversos devido à inibição dessas enzimas. Em plantas aquáticas, a redução da biomassa é geralmente observada após absorção de cianotoxinas que podem bioacumular em seus tecidos. Em plantas terrestres, os efeitos causados pelas microcistinas variam de inibição ao estímulo, como no desenvolvimento de plântulas ao estádio adulto, e incluem a redução de proteínas fosfatases 1 e 2A, estresse oxidativo, diminuição da atividade fotossintética e até mesmo apoptose celular, bem como a bioacumulação em tecidos de plantas. Assim, a irrigação de plantas cultivadas com água contaminada com microcistina não é apenas um problema econômico, mas torna-se um problema de saúde pública, devido à possibilidade de contaminação dos alimento, sendo uma via de exposição que requer um monitoramento cuidadoso por parte das autoridades responsáveis.Palavras-chave: bioacumulação, efeitos de microcistinas, plantas da agricultura, plantas aquáticas.

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“…The effect of cyanotoxins on aquatic and terrestrial plants has been previously reported by several authors (reviewed by , and there is an original report related to the effect of cyanotoxins (microcystins) on leguminous plants especially on infection and nodule initiation of alfafa (El Khalloufi et al 2011). The MC exposure affected the alfalfa biology and physiology as well as the symbiotic bacteria survival.…”

Section: Introductionmentioning

confidence: 89%

“…This way, the use of surface waters containing cyanobacterial blooms and their toxins for irrigation could be a threat for both the quality and the plant crop yield (Pflugmacher et al 2006;Peuthert et al 2007;Crush et al 2008;). Several studies have reported that the exposure to cyanobacteria aqueous extracts induced a significant reduction of the germination rate of terrestrial plant such as Lens esculenta, Zea mays, Triticum durum, Pisum sativum and Medicago sativa (Chen et al 2004;Pflugmacher et al 2006;Saqrane et al 2008;El Khalloufi et al 2011). In addition to the inhibitory effect on seed germination, could also have a negative impact on the growth, development and photosynthetic process of the seedling (Ko's et al 1995;Kurki-Helasmo and Meriluoto 1998;McElhiney et al 2001;Pflugmacher 2002;Pflugmacher et al 2006;Crush et al 2008;).…”

Section: Introductionmentioning

confidence: 96%

Cyanobacterial extracts containing microcystins affect the growth, nodulation process and nitrogen uptake of faba bean (Vicia faba L., Fabaceae)

et al. 2011

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The use of irrigation water containing cyanobacterial toxins may generate a negative impact in both yield and quality of agricultural crops causing significant economic losses. We evaluated the effects of microcystins (MC) on the growth, nodulation process and nitrogen uptake of a Faba bean cultivar (Vicia faba L., Fabaceae), particularly the effect of MC on rhizobia-V. faba symbiosis. Three rhizobial strains (RhOF4, RhOF6 and RhOF21), isolated from nodules of local V. faba were tested. The exposure of rhizobia to MC showed that the toxins had a negative effect on the rhizobial growth especially at the highest concentrations of 50 and 100 μg/l. The germination of faba bean seeds was also affected by cyanotoxins. We registered germination rates of 75 and 68.75% at the toxin levels of 50 and 100 μg/l as compared to the control (100%). The obtained results also showed there was a negative effect of MC on plants shoot, root (dry weight) and total number of nodules per plant. Cyanotoxins exposure induced a significant effect on nitrogen assimilation by faba bean seedlings inoculated with selected rhizobial strains RhOF6 and RhOF21, while the effect was not significant on beans seedling inoculated with RhOF4. This behavior of tolerant rhizobia-legumes symbioses may constitute a very important pathway to increase soil fertility and quality and can represent a friendly biotechnological way to remediate cyanotoxins contamination in agriculture.

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Allelopatic effects of cyanobacteria extracts containing microcystins on Medicago sativa–Rhizobia symbiosis

Cited by 43 publications

References 44 publications

Early physiological and biochemical responses of rice seedlings to low concentration of microcystin-LR

Early physiological and biochemical responses of rice seedlings to low concentration of microcystin-LR

Phytotoxicity associated to microcystins: a review

Cyanobacterial extracts containing microcystins affect the growth, nodulation process and nitrogen uptake of faba bean (Vicia faba L., Fabaceae)

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