Arsenic-Tolerant Fungi Improve the Growth of Corn (Zea mays) in Environments Impacted by Arsenate

Arsenic contamination found in soils and drinking water has been found to be hazardous to plant, livestock, and human health. To date, the majority of research on arsenic-resistant plants has focused on grasses and ferns, with little work highlighting arsenic’s potential effects on edible plant species. Here we show how a fungal endophyte and its endohyphal symbiont (a bacterium) react to arsenic contamination with corn in vitro. White Hybrid Sweet Corn (Silver Queen) was grown for one week in Ray Leach “Cone-Tainers”™ filled with perlite and was given one of six treatments with an additional treatment of arsenate, As(V), with concentrations of 5 ppm, 10 ppm, or 25 ppm. Corn plants were grown for an additional 2 weeks, after which they were harvested and weighed for biomass. To determine how endophytic fungi were affected by arsenic, mycelia from the samples were plated on Petri dishes of 2% malt extract agar (MEA) and were amended with 1 of 6 different concentrations of As(V). Fungal growth was measured every other day for 2 weeks. Results showed that corn plants treated with the endophyte-bacterium complex enhanced root growth with arsenic present; plant growth with arsenic was negatively affected when plants were treated with water only. Endophytic fungi demonstrated surprising resistance to arsenic contamination in vitro. Together these results suggest a potential, but previously unexplored role of endophytic fungi in mitigating arsenic contamination in agriculture systems.