Screening, Identification and Action Mechanism of T-2 Toxin-Degrading Strains

Abstract

The purpose of this study was to obtain microbial strains capable of high-efficiency degradation of T-2 toxin and to investigate their mechanism of action. T-2 toxin-degrading microorganisms were isolated from wheat and identified and their degradation characteristics were explored; their metabolites and mechanism of action were analyzed by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The results showed that two efficient T-2 toxin degrading strains, AFJ-2 and AFJ-3, were screened from 50 wheat samples and identified respectively as Curtobacterium sp. and Bacillus sp. by morphological observation and 16S rDNA sequence analysis. T-2 toxin at 5 μg/mL was completely degraded within 7 and 12 h by strains AFJ-2 and AFJ-3, respectively, and intracellular enzymes from them could significantly degrade T-2 toxin (P < 0.05) without adsorption. Strain AFJ-2 was able to convert T-2 toxin to HT-2 toxin and T-2 triol, while strain AFJ-3 could degrade T-2 toxin to produce neosolaniol (NEO). Based on the predicted degradation sites, it was hypothesized that the two strains could work together to degrade T-2 toxin to produce a new product, 4-deacetyl-NEO. The research results enrich the strain resource bank for the biodegradation of T-2 toxin, and provide a reference for the separation and purification of T-2 toxin-degrading enzymes and the excavation of functional genes.

Keywords

• t-2 toxin; screening; identification; biodegradation; metabolites; degradation mechanism