Biotransformation of Trichoderma spp. and Their Tolerance to Aromatic Amines, a Major Class of Pollutants

Abstract

ABSTRACTTrichodermaspp. are cosmopolitan soil fungi that are highly resistant to many toxic compounds. Here, we show thatTrichoderma virensandT. reeseiare 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 arylamineN-acetyltransferase (NAT), a xenobiotic-metabolizing enzyme that enables acetyl coenzyme A-dependent detoxification of AA. To assess whether theN-acetylation pathway enables AA tolerance inTrichodermaspp., we cloned and characterized NATs fromT. virensandT. reesei. We characterized recombinant enzymes by determining their catalytic efficiencies toward several toxic AA. Through a complementary approach, we also demonstrate that bothTrichodermaspecies efficiently metabolize 3,4-DCA. Finally, we provide evidence that NAT-independent transformation is solely (inT. virens) or mainly (inT. reesei) responsible for the observed removal of 3,4-DCA. We conclude thatT. virensand, to a lesser extent,T. reeseilikely utilize another, unidentified, metabolic pathway for the detoxification of AA aside from acetylation. This is the first molecular and functional characterization of AA biotransformation inTrichodermaspp. Given the potential ofTrichodermafor cleanup of contaminated soils, these results reveal new possibilities in the fungal remediation of AA-contaminated soil.