Glyphosate (GP) is one of the most used herbicides worldwide. As post-emergent, broad spectrum, nonselective systemic herbicide, it provides several agricultural benefits, controlling weeds. However, improper use during the decades resulted in GP contamination of soils and waters, raising concerns about potentially harmful effects on ecosystems, non-target organisms, including humans, and on crops. Among fungal ecosystem services there are the transformation and detoxification of pollutants. Therefore, fungal bioremediation can provide highly efficient, environmentally friendly and cost-effective solutions to cope with GP. This study aimed at selecting fungal species able to break down glyphosate and utilise it as nutritional source. Twenty-one saprotrophic strains were screened on Potato Dextrose Agar for their tolerance to two different concentrations of Round Up (RU), GP commercial product, corresponding to 1 mM and 10 mM of GP content. Tolerant strains were further tested for their ability to exploit RU as carbon (C) or phosphorus (P) source on Czapeck Dox Agar without C or P with the same RU concentrations. For all three screenings, diametric growth was measured. Considering the screenings’ results, Purpureocillium lilacinum was selected for further tests because of its performance and wide application in agricultural biotechnologies. To assess its ability to break down GP using it as a nutritional source of P, an experiment in Czapeck Dox Broth (CDB) was set up. Difference in toxicity between RU and GP (analytical standard), was studied at 1 mM concentration in CDB without P. Moreover, to evaluate the influence of nutritional stress on degradation process and a possible cometabolism, a treatment with RU concentration equivalent to 10 mM GP, was set up in CDB and CDB without P. Cultural media of these tests were analysed by UV-Vis spectrophotometry to assess GP degradation and by HPLC-MS-MS to assess the degradation metabolites produced. Our results show that all the species were able to tolerate RU at the lowest concentration, but only 13 at 10mM. All the 13 species tested for the use of GP as the only source of P and C were able to grow at a concentration of 1mM, while at 10 mM 12 species grew in the absence of P and only 10 in the absence of C. P. lilacinum grew in all the tested conditions. Pure GP was found to be more toxic than RU, resulting in a drastic reduction in biomass development. Finally, nutritional stress was found to affect the development of the fungal biomass, although the fungus grew both in enrichment condition and in complete medium.

Glyphosate-eating fungi: potentiality of saprotrophic fungi to break down glyphosate and utilise it as nutritional source / Spinelli, Veronica; Ceci, Andrea; DAL BOSCO, Chiara; Gentili, Alessandra; Persiani, Anna Maria. - (2021). (Intervento presentato al convegno World Microbe Forum tenutosi a online).

Glyphosate-eating fungi: potentiality of saprotrophic fungi to break down glyphosate and utilise it as nutritional source

Veronica Spinelli
;
Andrea Ceci;Chiara Dal Bosco;Alessandra Gentili;Anna Maria Persiani
2021

Abstract

Glyphosate (GP) is one of the most used herbicides worldwide. As post-emergent, broad spectrum, nonselective systemic herbicide, it provides several agricultural benefits, controlling weeds. However, improper use during the decades resulted in GP contamination of soils and waters, raising concerns about potentially harmful effects on ecosystems, non-target organisms, including humans, and on crops. Among fungal ecosystem services there are the transformation and detoxification of pollutants. Therefore, fungal bioremediation can provide highly efficient, environmentally friendly and cost-effective solutions to cope with GP. This study aimed at selecting fungal species able to break down glyphosate and utilise it as nutritional source. Twenty-one saprotrophic strains were screened on Potato Dextrose Agar for their tolerance to two different concentrations of Round Up (RU), GP commercial product, corresponding to 1 mM and 10 mM of GP content. Tolerant strains were further tested for their ability to exploit RU as carbon (C) or phosphorus (P) source on Czapeck Dox Agar without C or P with the same RU concentrations. For all three screenings, diametric growth was measured. Considering the screenings’ results, Purpureocillium lilacinum was selected for further tests because of its performance and wide application in agricultural biotechnologies. To assess its ability to break down GP using it as a nutritional source of P, an experiment in Czapeck Dox Broth (CDB) was set up. Difference in toxicity between RU and GP (analytical standard), was studied at 1 mM concentration in CDB without P. Moreover, to evaluate the influence of nutritional stress on degradation process and a possible cometabolism, a treatment with RU concentration equivalent to 10 mM GP, was set up in CDB and CDB without P. Cultural media of these tests were analysed by UV-Vis spectrophotometry to assess GP degradation and by HPLC-MS-MS to assess the degradation metabolites produced. Our results show that all the species were able to tolerate RU at the lowest concentration, but only 13 at 10mM. All the 13 species tested for the use of GP as the only source of P and C were able to grow at a concentration of 1mM, while at 10 mM 12 species grew in the absence of P and only 10 in the absence of C. P. lilacinum grew in all the tested conditions. Pure GP was found to be more toxic than RU, resulting in a drastic reduction in biomass development. Finally, nutritional stress was found to affect the development of the fungal biomass, although the fungus grew both in enrichment condition and in complete medium.
2021
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1620353
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact