Abstract
Bordetella sp. CTN-16 (GenBank FJ598326) can degrade chlorothalonil (CTN) but not carbendazim (MBC), and Microbacterium sp. MBC-3 (GenBank OK667229) can degrade MBC but not CTN. A functional strain BD2 was obtained by protoplast fusion of CTN-16 and MBC-3 to generate a fusant with improved degradation efficiency of CTN and MBC. Fusant-BD2 with eighth transfer on a medium containing CTN and two antibiotics was obtained. To identify and confirm the genetic relationship between parental strains and fusion strain BD2, scanning electron microscopy (SEM), random amplified polymorphic DNA (RAPD), and 16S ribosomal RNA (rRNA) gene sequences analysis were carried out. SEM analysis illustrated BD2 and its parents had some slight differences in the cell morphology. Fusant-BD2 not only possessed the same bands as parental strains but also had its specific bands analyzed through RAPD. The genetic similarity indices for BD2 and its parental strains CTN-16 and MBC-3 are 0.571 and 0.428, respectively. The degradation rates of CTN and MBC were 79.8% and 65.2% in the inorganic salt solution containing 50 mg·L−1 CTN and 50 mg·L−1 MBC, respectively, and the degradation efficiencies were better than the parental strains CTN-16 and MBC-3. This study provides a prospect for the application of fusion strain BD2 in bioremediation of CTN and MBC contaminated sites.
Highlights
Chlorothalonil [2, 4, 5, 6-tetrachloroisophthalonitrile (CTN)] is a non-systemic broad-spectrum fungicide that has been used to prevent and control various crop fungal diseases (Tang et al, 2017)
With MBC as the only carbon and energy source, several strains of MBC degrading bacteria were isolated, and the strain MBC-3 with high degradation efficiency was selected for further study
Phylogenetic analysis of 16S ribosomal RNA (rRNA) gene sequence showed that strain MBC-3 belonged to Microbacterium species and formed a subclade with Microbacterium Shaanxiense KJ735510T with a high bootstrap value of 95.9% (Figure 1)
Summary
Chlorothalonil [2, 4, 5, 6-tetrachloroisophthalonitrile (CTN)] is a non-systemic broad-spectrum fungicide that has been used to prevent and control various crop fungal diseases (Tang et al, 2017). In China, CTN is often used in greenhouses for various vegetables, fruits, rice, and other cash crops or to prevent lawn fungal foliar disease (Sakkas et al, 2002; Wu et al, 2012). CTN is highly toxic to birds and aquatic invertebrates (Ren et al, 2011). CTN is absorbed by the soil and it has a half-life of up to 100 days, which could cause great pollution to soil and environment (Shi et al, 2010). Increasing concerns about the toxicity of CTN has resulted in the demand for novel methods to remove environmental CTN contamination safely and effectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
