Novel soil bacterium strain desulfitobacterium sp. PGC-3-9 detoxifies trichothecene mycotoxins in wheat via de-epoxidation under aerobic and anaerobic conditions

Abstract

Trichothecenes are themost commonmycotoxins contaminating small grain cerealsworldwide. The C12,13 epoxide group in the trichothecenes was identified as a toxic group posing harm to humans, farmanimals, and plants. Aerobic biological de-epoxidation is considered the idealmethod of controlling these types of mycotoxins. In this study, we isolated a novel trichothecene mycotoxin-de-epoxidating bacterium, Desulfitobacterium sp. PGC-3-9, from a consortium obtained from the soil of a wheat field known for the occurrence of frequent Fusarium head blight epidemics under aerobic conditions. AlongwithMMYPFmedia, a combination of two antibiotics (sulfadiazine andtrimethoprim) substantially increased the relative abundance of Desulfitobacterium species from 1.55% (aerobic) to 29.11% (aerobic) and 28.63%(anaerobic). Asingle colony purified strain, PGC-3-9,was isolated and a 16S rRNAsequencing analysis determined that it was Desulfitobacterium. The PGC-3-9 strain completely de-epoxidated HT-2, deoxynivalenol (DON), nivalenol and 15-acetyl deoxynivalenol, and efficiently eliminatedDONinwheat grains under aerobic and anaerobic conditions. The strain PGC-3-9 exhibited high DON de-epoxidation activity at awide range of pH(6-10) and temperature (15-50 °C) values under both conditions. This strain may be used for the development of detoxification agents in the agriculture and feed industries and the isolation of de-epoxidation enzymes.