RESUMO
Triclocarban (TCC) and its metabolite, 3,4-dichloroaniline (DCA), are classified as emerging organic contaminants (EOCs). Significant concerns arise from water and soil contamination with TCC and its metabolites. These concerns are especially pronounced at high concentrations of up to approximately 20 mg/kg dry weight, as observed in wastewater treatment plants (WWTPs). Here, a TCC-degrading co-culture system comprising Rhodococcus rhodochrous BX2 and Pseudomonas sp. LY-1 was utilized to degrade TCC (14.5 mg/L) by 85.9% in 7 days, showing improved degradation efficiency compared with monocultures. A combination of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), genome sequencing, transcriptomic analysis, and quantitative reverse transcription-PCR (qRT-PCR) was performed. Meanwhile, through the combination of further experiments involving heterologous expression and gene knockout, we proposed three TCC metabolic pathways and identified four key genes (tccG, tccS, phB, phL) involved in the TCC degradation process. Moreover, we revealed the internal labor division patterns and connections in the co-culture system, indicating that TCC hydrolysis products were exchanged between co-cultured strains. Additionally, mutualistic cooperation between BX2 and LY-1 enhances TCC degradation efficiency. Finally, phytotoxicity assays confirmed a significant reduction in the plant toxicity of TCC following synergistic degradation by two strains. The in-depth understanding of the TCC biotransformation mechanisms and microbial interactions provides useful information for elucidating the mechanism of the collaborative biodegradation of various contaminants.
RESUMO
Licorice is a well-known Chinese medicinal plant that is widely used to treat multiple diseases and process food; however, wild licorice is now facing depletion. Therefore, there is an urgent need to identify and protect licorice germplasm diversity. In this study, metabolomic and transcriptomic analyses were conducted to investigate the biodiversity and potential medicinal value of the rare wild Glycyrrhiza squamulose. A total of 182 differentially accumulated metabolites and 395 differentially expressed genes were identified by comparing Glycyrrhiza uralensis and Glycyrrhiza squamulose. The molecular weights of the chemical component of G. squamulose were comparable with those of G. uralensis, suggesting that G. squamulose may have medicinal value. Differentially accumulated metabolites (DAMs), mainly flavonoids such as kaempferol-3-O-galactoside, kaempferol-3-O-(6"malonyl) glucoside, and hispidulin-7-O-glucoside, showed potential vitality in G. squamulose. Comparative transcriptomics with G. uralensis showed that among the 395 differentially expressed genes (DEGs), 69 were enriched in the isoflavonoid biosynthesis pathway. Multiomics analysis showed that the distinction in flavonoid biosynthesis between G. squamulose and G. uralensis was strongly associated with the expression levels of IF7GT and CYP93C. In addition to identifying similarities and differences between G. squamulose and G. uralensis, this study provides a theoretical basis to protect and investigate rare species such as G. squamulose.
RESUMO
Triclocarban (TCC), an emerging organic contaminant (EOC), has become a severe threat to soil microbial communities and ecological security. Here, the TCC-degrading strain Rhodococcus rhodochrous BX2 and DCA-degrading strain Pseudomonas sp. LY-1 (together referred to as TC1) were immobilized on biochar to remove TCC and its intermediates in TCC-contaminated soil. High-throughput sequencing was used to investigate the microbial community structure in TCC-contaminated soil. Analysis of co-occurrence networks was used to explore the mutual relationships among soil microbiome members. The results showed that the immobilized TC1 significantly increased the removal efficiency of TCC from 84.7 to 92.7% compared to CK (no TC1 cells on biochar) in 10 mg/L TCC liquid medium. The utilization of immobilized TC1 also significantly accelerated the removal of TCC from contaminated soil. Microbial community analysis revealed the crucial microorganisms and their functional enzymes participating in TCC degradation in soil. Moreover, the internal labor division patterns and connections of TCC-degrading microbes, with a focus on strains BX2 and LY-1, were unraveled by co-occurrence networks analysis. This work provides a promising strategy to facilitate the bioremediation of TCC in soil, which has potential application value for sustainable biobased economies.
