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

Abstract

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.

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

“…PS II fluorescence was less sensitive than plant biomass, varying only in plants exposed to the highest toxin dose . Lahrouni et al (2012) reported differences in growth of rhizobia inoculated Medicago sativa (e.g. shoot and root DW variations) when exposed for 6 weeks to 100 lg/L MC M. aeruginosa extracts.…”

“…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.…”

Exposure of Lycopersicon Esculentum to Microcystin-LR: Effects in the Leaf Proteome and Toxin Translocation from Water to Leaves and Fruits

“…Growth inhibition has also been reported in other crops [19,20]. MCs also have a negative impact on seed germination and root development [20,21,22,23] and have recently been shown to inhibit nodulation and Rhizobia growth with the potential for impairment of nitrogen uptake in leguminous crops [24,25]. Moreover evidence was collected at the molecular level, which highlighted the physiological stress of the plants after exposure to MCs [20,24,26,27,28,29].…”

EFFECT OF INOCULATION BY MOROCCAN ROCK PHOSPHATE-SOLUBILIZING RHIZOBIA, VERSUS PHOSPHORUS FERTILIZATION, ON THE GROWTH AND THE PHOSPHORUS UPTAKE BY Vicia faba

“…Inoculums preparation: We used the same protocol reported above in the paragraph "Phosphate solubilization test on agar medium". The inoculum was prepared by growing the rhizobial strain in YEM liquid medium at 28°C for 2-3 days to obtain an optical density (OD) of 1 at 600 nm (approximately 10 9 colonies forming units (CFU)/mL) as described previously (Lahrouni et al, 2012;Oufdou et al, 2014). Inoculation and transfer to pot: Uniformly-germinated seedlings were immersed for 30 min in individual rhizobial liquid culture of each of the tested strains RHOF147, RHOF174, RHOF170 or RHOF171.…”