Biotransformation of Organophosphate Esters by Rice and Rhizosphere Microbiome: Multiple Metabolic Pathways, Mechanism, and Toxicity Assessment

Abstract

The biotransformation behavior and toxicity of organophosphate esters (OPEs) in rice and rhizosphere microbiomes were comprehensively studied by hydroponic experiments. OPEs with lower hydrophobicity were liable to be translocated acropetally, and rhizosphere microbiome could reduce the uptake and translocation of OPEs in rice tissues. New metabolites were successfully identified in rice and rhizosphere microbiome, including hydrolysis, hydroxylated, methylated, and glutathione-, glucuronide-, and sulfate-conjugated products. Rhizobacteria and plants could cooperate to form a complex ecological interaction web for OPE elimination. Furthermore, active members of the rhizosphere microbiome during OPE degradation were revealed and the metagenomic analysis indicated that most of these active populations contained OPE-degrading genes. The results of metabolomics analyses for phytotoxicity assessment implied that several key function metabolic pathways of the rice plant were found perturbed by metabolites, such as diphenyl phosphate and monophenyl phosphate. In addition, the involved metabolism mechanisms, such as the carbohydrate metabolism, amino acid metabolism and synthesis, and nucleotide metabolism in Escherichia coli, were significantly altered after exposure to the products mixture of OPEs generated by rhizosphere microbiome. This work for the first time gives a comprehensive understanding of the entire metabolism of OPEs in plants and associated microbiome, and provides support for the ongoing risk assessment of emerging contaminants and, most critically, their transformation products.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Indoor Air and Dust from Multiple Microenvironments in China

“…BEHPP (C 22 H 39 O 4 P, m / z 399.26531, RT = 14.16 min) is structurally similar to 2-ethylhexyl diphenyl phosphate (EHDPP) and was identified with fragments of 57.07001 (C 4 H 9 , −7.277 ppm), 95.04929 (C 6 H 7 O, −4.206 ppm), and 175.01534 (C 6 H 8 O 4 P, −3.886 ppm) (Figure S14). Abundant BEHPP has been detected in various environmental matrices, including air, soil, dust, lake sediment, as well as rice, and wild fish . Nevertheless, BEHPP was detected in the indoor environment with DFs of 50 and 90% in the air and dust samples, respectively.…”

“…BEHPP S14). Abundant BEHPP has been detected in various environmental matrices, including air, 62 soil, 24 dust, 23 lake sediment, 17 as well as rice, 88 and wild fish. 89 Nevertheless, BEHPP was detected in the indoor environment with DFs of 50 and 90% in the air and dust samples, respectively.…”

Distribution and Risk Assessment of Organophosphate Esters in Agricultural Soils and Plants in the Coastal Areas of South China

“…The procedures of sample extraction and purification have been described in other references [ 48 ] and were used with some modifications. The soil and plant samples were extracted with ultrasonic extraction (Supmile, Jiangsu, China).…”

“…Research on OPEs in crops is still in the early stages compared to research on their presence in soils. Yu [ 48 ] conducted a study on the biotransformation behavior and toxicity of OPEs through hydroponic experiments. The findings revealed that OPEs with lower hydrophobicity exhibited greater ease of translocation to the top.…”

Aerobic Microbial Transformation of Fluorinated Liquid Crystal Monomer: New Pathways and Mechanism

“…The following criteria were used for transformation product identification: (1) peaks with intensity above threshold, (2) the presence in DTMDPB-amended enrichment culture and the absence or significantly lower levels in the control experiment with sterilized enrichment culture, and (3) a reasonable chemical formula derived from the exact mass (mass accuracy tolerance <5 ppm) and the isotopic pattern (≥80%). The confidence levels of those identified transformation products were determined according to previous studies. − …”