Chlorothalonil degradation by Ochrobactrum lupini strain TP-D1 and identification of its metabolites

Abstract

Chlorothalonil (2, 4, 5, 6-tetrachloroisophthalonitrile, TPN) has been widely used as a wide-spectrum fungicide in China and other countries, and is considered to be an important soil and water contaminant. Here we report the isolation and characterization of a novel TPN-degrading bacterial strain TP-D1 from a heavily TPN-polluted soil in Henan Province, China, and identified it as a strain of Ochrobactrum lupini based on 16S rRNA gene sequence analysis and its morphological, biochemical, and physiological characteristics. Strain TP-D1 could degrade 90.4 and 99.7% of TPN after 4-and 7-day incubation in mineral salt broth with 50 mg TPN l -1 and in autoclaved soil with 50 lg TPN g -1 , respectively. Two new metabolites, methyl 2, 5, 6-trichloro-3-cyano-4-methoxy-benzoate (metabolite C) and methyl 3-cyano-2, 4, 5, 6-tetrachlorobenzoate (metabolite D), were detected besides previously reported 4-hydroxy-2, 5, 6-trichloroisophthalonitrile (TPN-OH, metabolite A). This result suggests that the cyano-group in TPN could be converted into amide groups by strain TP-D1, and reveal the biodegradation mechanism of TPN in soil.

The influence of chlorothalonil on the activity of soil microorganisms and enzymes

“…It was first registered in the United States in 1966. In fungus cells, it leads to the inhibition of enzymes responsible for cellular respiration (Shi et al 2011 ). Chlorothalonil is very effective in protecting plants against fungal diseases caused mainly by Phytophthora infestans and Alternaria solani , and prevents germination of fungal spores (Leitao et al 2014 ).…”

Role of Dehalogenases in Aerobic Bacterial Degradation of Chlorinated Aromatic Compounds

“…In another study, the chd gene was cloned from a chlorothalonildegrading strain, Ochrobactrum lupine TP-D1, which showed 98.4% similarity with that of Pseudomonas sp. CTN-3 [30]. This gene was closely associated with the insertion element IS-Olup.…”

Probiotic strain Stenotrophomonas acidaminiphila BJ1 degrades and reduces chlorothalonil toxicity to soil enzymes, microbial communities and plant roots

“…Several methods such as hydrolysis, photolysis, catalytic and bio-degradation are known to reduce fungicide residues in the soil environment. (Ghauch and Tuqan 2008 ; Rouchaud et al 1988 ; Sakkas et al 2002 ; Shi et al 2011 ; Wu et al 2016 ). Among these, the microbial driven removal of fungicides is a cost-effective and eco-friendly way to detoxify the contaminated sites.…”

“…Among these, the microbial driven removal of fungicides is a cost-effective and eco-friendly way to detoxify the contaminated sites. While some microbial strains such as Bacillus cereus NS1, Pseudomonas CDS-8, and Ochrobactrum lupini TP-D1, etc., are known to degrade chlorothalonil in the soil and water environments (Shi et al 2011 ; Wu et al 2016 ; Zhang et al 2007 ). The Stenotrophomonas acidaminiphila BJ1, a previously isolated strain in our laboratory, could remove 93.2% of chlorothalonil (50 mg L −1 ) within 7 days in the optimal liquid media.…”

“…The Stenotrophomonas acidaminiphila BJ1, a previously isolated strain in our laboratory, could remove 93.2% of chlorothalonil (50 mg L −1 ) within 7 days in the optimal liquid media. Although microbial-driven removal of chlorothalonil is known (Shi et al 2011 ; Zhang et al 2014a ), there is a debate about whether these strains colonize and compete for the same ecological niche with native species in the contaminated sites. Moreover, the role of microbial species in reducing chlorothalonil toxicity to soil enzymes, microbes, and plant roots, remains to be studied in situ.…”