Bioremediation of Pendimethalin by the Saprophytic Fungi Coriolopsis rigida and Fusarium lateritium Rescues Symbiotic Abilities of Phaseolus vulgaris and Increases Soil Microbial Activities

The increment in the use of herbicides in the last decades has reduced the soil microbial diversity affecting the symbiotic associations between legumes and soil microorganisms, which are essential for plant nutrition and therefore agricultural production. Consequently, in this work, we have evaluated the potential of two saprophytic fungi as a bioremediation tool for the recovery of soil microbial activity and the symbiotic abilities in Phaseolus vulgaris . Initially, the saprophytic fungi Coriolopsis rigida and Fusarium lateritium were tested for their capacity to degrade pendimethalin in vitro. After that, the ability of both fungi to improve the symbiotic capacity of Phaseolus vulgaris was assessed in a pot trial in which parameters related to plant growth, nitrogen fixation and arbuscular mycorrhizal fungi (AMF) root colonization were analysed together with the soil microbial activity. We observed that C. rigida and F. lateritium utilized pendimethalin as a carbon source and mitigated the plant biomass reduction as well as the inhibition of nitrogen fixation and AMF root colonization provoked by the herbicide in P. vulgaris . Additionally, the inoculation with both fungi led to increased microbial activities in the soil sprayed with herbicide, which was associated with the dissipation of pendimethalin induced by both fungi in inoculated soils. The results confirmed the effectiveness of C. rigida and F. lateritium as bioremediation tool for the removal of pendimethalin to improve soil microbial activity and the symbiotic interactions between soil microbes and P. vulgaris. These findings contribute to the development of sustainable agricultural practices.