Biotransformation of trichoderma spp. and their tolerance to aromatic amines, a major class of pollutants

Abstract

Biotransformation of Trichoderma spp. and Their Tolerance to Aromatic Amines, a Major Class of Pollutants Angélique Cocaign, a Linh-Chi Bui, a Philippe Silar, b, c Laetitia Chan Ho Tong, b, c Florent Busi, a Aazdine Lamouri, d Christian Mougin, e Fernando Rodrigues-Lima, a Jean-Marie Dupret, a Julien DairouaUniversité Paris Diderot, Sorbonne Paris Cité, Unit of Functional and Adaptive Biology (BFA), EAC 4413 CNRS, Paris, Francea; Université Paris-Sud 11, Institute of Genetics and Microbiology, CNRS UMR 8621, Orsay, Franceb; Université Paris Diderot, Sorbonne Paris Cité, Institut des Energies de Demain, Paris, Francec; Université Paris Diderot, Sorbonne Paris Cité, ITODYS UMR CNRS 7086, Paris, Franced; INRA, UR 251 PESSAC, Physico-Chemistry and Ecotoxicology of Soils from Contaminated Agrosystems, Versailles, Francee Trichoderma spp. are cosmopolitan soil fungi that are highly resistant to many toxic compounds. Here, we show that Trichoderma virens and T. reesei are tolerant to aromatic amines (AA), a major class of pollutants including the highly toxic pesticide residue 3,4-dichloroaniline (3,4-DCA). In a previous study, we provided proof-of-concept remediation experiments in which another soil fungus, Podospora anserina, detoxifies 3,4-DCA through its arylamine N-acetyltransferase (NAT), a xenobiotic-metabolizing enzyme that enables acetyl coenzyme A-dependent detoxification of AA. To assess whether the N-acetylation pathway enables AA tolerance in Trichoderma spp., we cloned and characterized NATs from T. virens and T. reesei. We characterized recombinant enzymes by determining their catalytic efficiencies toward several toxic AA. Through a complementary approach, we also demonstrate that both Trichoderma species efficiently metabolize 3,4-DCA. Finally, we provide evidence that NAT-independent transformation is solely (in T. virens) or mainly (in T. reesei) responsible for the observed removal of 3,4-DCA. We conclude that T. virens and, to a lesser extent, T. reesei likely utilize another, unidentified, metabolic pathway for the detoxification of AA aside from acetylation. This is the first molecular and functional characterization of AA biotransformation in Trichoderma spp. Given the potential of Trichoderma for cleanup of contaminated soils, these results reveal new possibilities in the fungal remediation of AA-contaminated soil. © 2013, American Society for Microbiology. All Rights Reserved.