Physiological and Molecular Characterization of Active Fungi in Pesticides Contaminated Soils for Degradation of Glyphosate

Abstract Pesticide contamination is a substantial problem in controlling agricultural pests. Understanding the physiological and molecular characteristics of naturally occurring fungi in the pesticide contaminated environment is crucial to managing glyphosate contamination. The study was aimed at isolating and characterizing soil fungi for their physiological roles towards glyphosate degradation. Pure cultures of fungi were isolated from soil contaminated with glyphosate at farms in Lagos, Nigeria. The cultures were grown on minimal salt agar media amended with glyphosate. The best isolates exhibiting good tolerance to the glyphosate were characterized using molecular techniques. The BLAST search indicated that the fungi belong to four Aspergillus species (Aspergillus flavus strain JN-YG-3-5, Aspergillus niger strain APBSDSF96, Aspergillus fumigatus strain FJAT-31052 and Aspergillus flavus strain APBSWTPF130, Trichoderma gamsii and Penicillium simplicissimum. The biodegradation study of the glyphosate by the selected fungi species showed the presence of Aminomethylphosphonic Acid (AMPA) except for Aspergillus fumigatus strain FJAT-31052. This validates AMPA as a valid pathway for degradation of glyphosate by fungi. Annotation analysis of the partial gene sequence shows that the strains possess protein coding gene clusters for glyphosate utilization and other physiological activities. A comparative genome analysis revealed that the genomes of the fungi were highly similar with genomes of environmental samples especially to Clostridium perfringens The GhostKOALA output confirmed that CYP2W1 gene (Cytochrome P450, fungi type) was present in Aspergillus fumigatus strain FJAT-31052 which was absent in genome of other fungi. The physiological and molecular characteristics of Aspergillus fumigatus strain FJAT-31052 clearly show that this isolate is a useful organism for managing contamination by glyphosate pesticide. Consequently, the isolated microorganism strains can be used in other soils as microbial inoculants for bio-augmentation combining them for their probable ability to degrade pesticides along with their biotechnological applications like enzyme-based remediation.