P-396 - Alleviation of Heavy Metal Stress in Plants Growing in Contaminated Soils via Plant-Fungus Symbiotic Interactions

Primary sources of soil contamination stem from anthropogenic activities such as mining, chemical production, and metal processing industries. Numerous abandoned mining sites across EU member states pose environmental threats, with contaminants dispersing due to extreme weather events exacerbated by climate change. Biological methods, including bioremediation, utilise living organisms to detoxify soil. Microorganisms can produce chelates or modify metal oxidation states, altering their bioavailability. Microbes in mine wastelands likely form mutualistic relationships with plants, enhancing tolerance to heavy metals (HM). This study aimed to characterise beneficial endophytic fungi from the roots of plants endemic to the Iberian Peninsula, collected from the spoil heap of the abandoned Cerro de la Plata mine in Bustarviejo (Madrid), Spain. Their capacity to protect plants from high HM concentrations was evaluated by inoculating Arabidopsis thaliana and monitoring HM stress tolerance compared to non-inoculated controls. Isolates were ranked based on their potential to confer HM stress tolerance. The collection comprised multiple beneficial endophytes that established plant-microbe interactions, mitigating HM stress effects on the host. This study provides evidence of beneficial soil microbes that can enhance cover crop tolerance to HM and prevent the dispersion of toxic substances from exposed mine wastelands.