Isolation of a degrading strain of Fusarium verticillioides and bioremediation of glyphosate residue

• Published in: Pesticide biochemistry and physiology 2022-03, Vol.182, p.105031, Article 105031
• Main Authors: Guo, Jing, Song, Xiuli, Li, Rongxing, Zhang, Qi, Zheng, Shengwei, Li, Qiucheng, Tao, Bo
• Format: Article
• Language: English
• Subjects: 3-Phosphoshikimate 1-Carboxyvinyltransferase - genetics; Biodegradation, Environmental; Bioremediation; Degrading fungus; Epsps; Fusarium; Glycine - analogs & derivatives; Glyphosate; Herbicide Resistance - genetics; Herbicides - pharmacology; Phylogeny; Q-PCR; Tolerance
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2021.105031

Glyphosate is a broad-spectrum and nonselective organophosphorus herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme in the shikimate pathway in plants. A glyphosate-resistant fungus identified as Fusarium verticillioides was screened from soil subjected to long-term glyphosate application, and this fungus could grow in inorganic salt medium containing 90 mmol/L glyphosate. The optimum culture conditions identified via the response surface curve method were 28 °C and pH 7.0. The target gene epsps was cloned in this study, and the open reading frame contained 1170 nucleotides and putatively encoded 389 amino acid residues. Phylogenetic analysis showed that this gene belonged to class I, genes naturally sensitive to glyphosate. q-PCR confirmed that the relative expression level of the epsps gene was low, and no significant difference in expression was observed among different glyphosate concentrations at 12 h or 48 h. On day 28, the degradation by Fusarium verticillioides C-2 of sterilized soil and unsterilized soil supplemented with 60 mg/kg glyphosate reached 72.17% and 89.07%, respectively, and a significant difference was observed between the treatments with and without the glyphosate-degrading strain. The recovery of soil dehydrogenase activity after the addition of Fusarium verticillioides was significantly higher than that in the absence of the degrading fungus on the 28th day. The results showed that C-2 is a highly effective glyphosate-degrading strain with bioremediation potential for glyphosate-contaminated soil. [Display omitted] •A highly glyphosate-tolerant fungal strain was isolated.•The target gene epsps was cloned and classified as naturally sensitive EPSP class I.•After 28 days, the glyphosate degradation efficiency was 89.07%.•Soil dehydrogenase activity was significantly restored.