Bioremediation and microbial-assisted phytoremediation of heavy metals by endophytic Fusarium species isolated from Convolvulus arvensis

Abstract

Endophytic fungi are very prolific organisms associated with a wide range of host plants. Although they contribute to tolerance of their hosts against environmental stress, their role in response of plants to metal toxicity has not been thoroughly illuminated. Therefore, in this study, endophytic fungi were isolated from Convolvulus arvensis and their potential to bioremediate heavy metals from liquid media was assessed. Furthermore, the effect of the endophytic fungi on heavy metal tolerance, accumulation, and translocation by host plants were evaluated. The results revealed that Fusarium falciforme (MW898136) and Fusarium sp. (MW898137) possess a significant ability for bio-removal of cadmium from aqueous solutions as their tolerance indexes were >1. The bioaccumulation capacity reached 276.5 and 101.6 μg/g with bioremediation percentages of 82.4% and 76.5%, respectively. Fusarium falciforme (MW898136) filtrates, in the presence of cadmium, stimulated the growth of Triticum aestivum, and dramatically decreased cadmium bioaccumulation from 30.18 to 7.06 μg/g. The presence of F. falciforme (MW898136) in cadmium-stressed soil assisted Phaseolus vulgaris to produce more biomass, uptake higher amounts of cadmium by roots, and decreased the translocation of cadmium from roots to shoots. These results suggest that F. falciforme (MW898136) has the ability to immobilize cadmium and decrease its bioavailability in both liquid media and soil through absorption and/or accumulation.