The influence of microbial communities for triadimefon enantiomerization in soils with different pH values.

Enantiomers of chiral molecules can undergo interconversion leading to markedly different toxicities, which can introduce significant uncertainty when evaluating biological and environmental fates. However, enantiomerization (the reversible conversion of one enantiomer into the other) related to soil microorganism is rarely understood. For better understanding, S-triadimefon and R-triadimefon enantiopure were incubated in different soils with different pH value. Both high-performance liquid chromatography and high-throughput sequencing technology were used to explore target analytes quantitatively and microbial taxa related to the conversion process. Results revealed a significant enantiomerization among the soils. The alkaline soil from Beijing had a faster conversion than neutral soil from Changchun, while acidic soil from Wuhan had no conversion. At the same results, analysis of bacteria community showed higher abundance of Arthrobacter and Halomonas genus in alkaline soil than neutral soil after treatments, but the acidic soil was lower. Moreover, Arthrobacter and Halomonas were responsible for converting S-triadimefon to R-triadimefon and R-triadimefon to S-triadimefon in alkaline and neutral soil, respectively. Thus, these genera may be one of the reasons to explain the enantiomerization in different soils observed in this study. Thus, research at microbial level is necessary for efficient ecological risk assessment of chiral fungicide.