Dioxins/furans disturb the life cycle of the arbuscular mycorrhizal fungus, Rhizophagus irregularis and chicory root elongation grown under axenic conditions

Abstract

Arbuscular mycorrhizal fungi (AMF)-assisted phytoremediation is a promising technology for sustainable removal of hazardous pollutants like dioxins/furans (PCDD/F) from the soil. However, little is known on AMF development in the presence of the persistent organic pollutants, PCDD/F. Thus, the present work aims at investigating the impact of increasing PCDD/F concentrations on the development of both partners of the symbiosis: the AMF, Rhizophagus irregularis and the chicory roots, Cichorium intybus L. grown under axenic conditions. Our results show that even R. irregularis spore germination is not affected by PCDD/F, it occurred mainly in linear way. However, root colonization, extra-radical hyphal elongation and sporulation are reduced by 40, 30, and 75%, respectively, at the highest PCDD/F concentration. In addition, while non-mycorrhizal root growth (length and dry weight) decreased at the highest PCDD/F concentration, no negative effect was observed on the dry weight of mycorrhizal roots. In conclusion, our findings show that although high PCDD/F concentrations disturb the main stages of R. irregularis development, the AMF remains able to fulfill its life cycle in the presence of PCDD/F. Moreover, the mycorrhizal inoculation protects the host plant against PCDD/F phytotoxicity. AMF could thus represent an interesting amendment option to assist phytoremediation of PCDD/F contaminated soils.

Keywords:

• Arbuscular mycorrhizal fungus
• development cycle
• dioxins/furans
• ecotoxicity
• in vitro culture
• Rhizophagus irregularis

Acknowledgments

This work has also been carried out in the framework of Halluin3R and Alibiotech projects which are financed by European Union (FEDER), French State and the French Region of Hauts de France. This work was also supported by l’Agence De l’Environnement et de la Maîtrise de l′Energie (ADEME, Angers, France).

Disclosure statement

No potential conflict of interest was reported by the author(s).