TY - JOUR
T1 - Adverse Metabolic Outcomes in Soil Pseudomonas Species Exposed to Polyethoxylated Tallow Amine and Glyphosate
AU - Mendonca, Caroll M.
AU - Reed, Michael L.
AU - Kukurugya, Matthew A.
AU - Aristilde, Ludmilla
N1 - Funding Information:
Research support and support for C.M.M. were both provided by a National Institute of Food and Agriculture grant (Hatch Project 1002230) awarded to L.A. Support for M.A.K. was provided by an Integrative Graduate Education and Research Traineeship (IGERT) from the U.S. National Science Foundation.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/8/13
Y1 - 2019/8/13
N2 - Polyethoxylated tallow amine (POEA) is a common surfactant used in glyphosate-based herbicide formulations to enhance the bioavailability of the active herbicide ingredient. Toxic effects of POEA exposure are well documented for aquatic organisms, but despite the widespread occurrence of POEA in soils, the potential effects on soil bacteria have not been investigated. Here we examined the growth and metabolic effects of POEA in three strains of plant-beneficial soil Pseudomonas species (Pseudomonas putida KT2440, P. putida S12, and P. protegens Pf-5) grown on succinate, a common root exudate. Compared to the rate of growth on only succinate, the addition of POEA resulted in up to 60% reduction in the biomass growth rate. In the presence of both POEA and glyphosate, the biomass growth rate either remained the same as during exposure to only POEA or decreased by only an additional 5-15%, thus indicating that growth inhibition was primarily caused by POEA. Metabolomics analysis of POEA-exposed cells identified, relative to control cells, disruption of metabolite levels in key biosynthetic pathways: accumulation of ribonucleotides and depletion of amino acids. Kinetic 13C flux experiments further revealed delayed de novo biosynthesis of pyrimidine ribonucleotides. Our findings thus highlight disconnects between carbon metabolism and biomass biosynthesis as potential adverse metabolic outcomes in POEA-exposed soil-beneficial bacteria.
AB - Polyethoxylated tallow amine (POEA) is a common surfactant used in glyphosate-based herbicide formulations to enhance the bioavailability of the active herbicide ingredient. Toxic effects of POEA exposure are well documented for aquatic organisms, but despite the widespread occurrence of POEA in soils, the potential effects on soil bacteria have not been investigated. Here we examined the growth and metabolic effects of POEA in three strains of plant-beneficial soil Pseudomonas species (Pseudomonas putida KT2440, P. putida S12, and P. protegens Pf-5) grown on succinate, a common root exudate. Compared to the rate of growth on only succinate, the addition of POEA resulted in up to 60% reduction in the biomass growth rate. In the presence of both POEA and glyphosate, the biomass growth rate either remained the same as during exposure to only POEA or decreased by only an additional 5-15%, thus indicating that growth inhibition was primarily caused by POEA. Metabolomics analysis of POEA-exposed cells identified, relative to control cells, disruption of metabolite levels in key biosynthetic pathways: accumulation of ribonucleotides and depletion of amino acids. Kinetic 13C flux experiments further revealed delayed de novo biosynthesis of pyrimidine ribonucleotides. Our findings thus highlight disconnects between carbon metabolism and biomass biosynthesis as potential adverse metabolic outcomes in POEA-exposed soil-beneficial bacteria.
UR - http://www.scopus.com/inward/record.url?scp=85070640783&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85070640783&partnerID=8YFLogxK
U2 - 10.1021/acs.estlett.9b00363
DO - 10.1021/acs.estlett.9b00363
M3 - Article
AN - SCOPUS:85070640783
SN - 2328-8930
VL - 6
SP - 448
EP - 455
JO - Environmental Science and Technology Letters
JF - Environmental Science and Technology Letters
IS - 8
ER -