Exposure to fomesafen alters the gut microbiota and the physiology of the earthworm Pheretima guillelmi

Effects of Three Pesticides on the Earthworm Lumbricus terrestris Gut Microbiota

“…It was found that pesticides both at the recommended application rate and at the rate increased by 10 times decreased the values of α-biodiversity indices. It is similar with the effect of other xenobiotics, such as heavy metals, microplastics, antibiotics (triclosan), pesticides (fomesafen), which significantly reduced the bacterial biodiversity in the digestive tracts of soil invertebrates ( Ma et al, 2017 ; Chen et al, 2020 ; Sun et al, 2020 ; Chang et al, 2021 ). Biodiversity reduction and changing of dominants in the bacterial community of the digestive tract led to a decrease in the biochemical activity of the intestinal contents and, therefore, affected the ability of the earthworm to assimilate the substrate.…”

“…Previously, Chang et al (2021) also found that the herbicide fomesafen at the recommended application rate caused significant differences in the relative abundance of Actinobacteria, Firmicutes, and Proteobacteria. Furthermore, it was found that the increased abundance of Proteobacteria can be considered as a potential marker of imbalance in the gut microbiota of many earthworm species ( Shin et al, 2015 ; Wang et al, 2022 ).…”

“…This data corresponds with previous research, where Proteobacteria, Actinobacteria, Firmucutes, Bacteroidetes, and Verrucomicrobia have been shown to be the dominant phyla in L. terrestris gut ( Knapp et al, 2009 ; Pass et al, 2015 ; Ma et al, 2017 ; Meier et al, 2021 ). The digestive tract of an earthworm is a microaerophilic and even anaerobic zone ( Byzov et al, 2015 ); hence, phyla Firmicutes and Actinobacteria, which are facultative and/or obligate anaerobes, dominate in the prokaryotic community of the gut ( Chang et al, 2021 ). On the other hand, Chloroflexi, the bacteria phylum which may be among dominants in E. fetida gut ( Liu et al, 2018 ), was not a dominant in L. terrestris gut due to the differences in burrowing and feeding habits of worms.…”

“…Comparison of pesticide concentrations in the variants with a 10-fold application rate with the values of acute and chronic toxicity of these pesticides for earthworms showed that even when the recommended application rate is 10-fold increased, the final concentration of the pesticide is more than 100 times lower than the values of acute and chronic toxicity of the same pesticide (0.008 mg/kg metribuzin versus LC 50 = 427 mg/kg and NOEC >52.3 mg/kg; 0.0002 mg/kg imidacloprid versus LC 50 = 10.7 mg/kg and NOEC = 0.178 mg/kg; 0.01 mg/kg benomyl versus LC 50 = 5.4 mg/kg and NOEC = 1.0 mg/kg; Supplementary Table S2 ). Thus, the microbial community of the intestinal tract is highly sensitive to soil pollutants ( Chang et al, 2021 ), hence, this type of research should be included in the practice of assessing the risks of pesticide application for non-target organisms.…”

“…DHL-02, Pseudomonas putida, Pantoea agglomerans and Pseudomonas taiwanensis increased ( Owagboriaye et al, 2021 ). Based on the results of molecular genetic analysis using high-throughput sequencing of the 16S RNA gene, it was found that the herbicide fomesafen might reduce bacterial diversity and shift the bacterial community structure of Pheretima guillelmi gut ( Chang et al, 2021 ). Nonetheless, there are no studies which examine the effects of pesticides on the gut microbiota of L. terrestris , one of the most common earthworm species.…”