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Dang B, Jia W, Ma S, Zhang X, Huang Y, Huang W, Han D, Zhang K, Zhao F, Zhang Y, Xu Z. Characterization of a novel nornicotine-degrading strain Mycolicibacterium sp. SMGY-1XX from a nornicotine-degrading consortium and preliminary elucidation of its biodegradation pathway by multi-omics analysis. JOURNAL OF HAZARDOUS MATERIALS 2023; 457:131777. [PMID: 37290356 DOI: 10.1016/j.jhazmat.2023.131777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/14/2023] [Accepted: 06/02/2023] [Indexed: 06/10/2023]
Abstract
Nicotine and nornicotine are all toxic alkaloids involved in the formation of carcinogenic tobacco-specific nitrosamines. Microbes play an important role in removing these toxic alkaloids and their derivatives from tobacco-polluted environments. By now, microbial degradation of nicotine has been well studied. However, limited information is available on the microbial catabolism of nornicotine. In the present study, a nornicotine-degrading consortium was enriched from a river sediment sample and characterized by metagenomic sequencing using a combination of Illumina and Nanopore technologies. The metagenomic sequencing analysis demonstrated that Achromobacter, Azospirillum, Mycolicibacterium, Terrimonas, and Mycobacterium were the dominant genera in the nornicotine-degrading consortium. A total of 7 morphologically distinct bacterial strains were isolated from the nornicotine-degrading consortium. These 7 bacterial strains were characterized by whole genome sequencing and examined for their ability to degrade nornicotine. Based on a combination of 16 S rRNA gene similarity comparisons, 16 S rRNA gene-based phylogenetic analysis, and ANI analysis, the accurate taxonomies of these 7 isolated strains were identified. These 7 strains were identified as Mycolicibacterium sp. strain SMGY-1XX, Shinella yambaruensis strain SMGY-2XX, Sphingobacterium soli strain SMGY-3XX, Runella sp. strain SMGY-4XX, Chitinophagaceae sp. strain SMGY-5XX, Terrimonas sp. strain SMGY-6XX, Achromobacter sp. strain SMGY-8XX. Among these 7 strains, Mycolicibacterium sp. strain SMGY-1XX, which has not been reported previously to have the ability to degrade nornicotine or nicotine, was found to be capable of degrading nornicotine, nicotine as well as myosmine. The degradation intermediates of nornicotine and myosmine by Mycolicibacterium sp. strain SMGY-1XX were determined and the nornicotine degradation pathway in strain SMGY-1XX was proposed. Three novel intermediates, myosmine, pseudooxy-nornicotine, and γ-aminobutyrate, were identified during the nornicotine degradation process. Further, the most likely candidate genes responsible for nornicotine degradation in Mycolicibacterium sp. strain SMGY-1XX were identified by integrating genomic analysis, transcriptomic analysis, and proteomic analysis. The findings in this study will help to expand our understanding on the microbial catabolism of nornicotine and nicotine and provide new insights into the nornicotine degradation mechanism by consortia and pure culture, laying a foundation for the application of strain SMGY-1XX for the removal, biotransformation, or detoxification of nornicotine.
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Affiliation(s)
- Bingjun Dang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
| | - Wei Jia
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Shuanglong Ma
- College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaoping Zhang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China; Flavors and Fragrance Engineering & Technology Research Center of Henan Province, Zhengzhou 450002, China
| | - Yao Huang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Wuxing Huang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Dan Han
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Kai Zhang
- School of Geographic Sciences, Xinyang Normal University, Xinyang 464000, China
| | - Fanchong Zhao
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Yuwei Zhang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Zicheng Xu
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
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Li X, Liu X, Lu W, Yin X, An S. Application progress of plant-mediated RNAi in pest control. Front Bioeng Biotechnol 2022; 10:963026. [PMID: 36003536 PMCID: PMC9393288 DOI: 10.3389/fbioe.2022.963026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/11/2022] [Indexed: 01/09/2023] Open
Abstract
RNA interference (RNAi)-based biopesticides are novel biologic products, developed using RNAi principles. They are engineered to target genes of agricultural diseases, insects, and weeds, interfering with their target gene expression so as to hinder their growth and alleviate their damaging effects on crops. RNAi-based biopesticides are broadly classified into resistant plant-based plant-incorporated protectants (PIPs) and non-plant-incorporated protectants. PIP RNAi-based biopesticides are novel biopesticides that combine the advantages of RNAi and resistant transgenic crops. Such RNAi-based biopesticides are developed through nuclear or plastid transformation to breed resistant plants, i.e., dsRNA-expressing transgenic plants. The dsRNA of target genes is expressed in the plant cell, with pest and disease control being achieved through plant-target organism interactions. Here, we review the action mechanism and strategies of RNAi for pest management, the development of RNAi-based transgenic plant, and the current status and advantages of deploying these products for pest control, as well as the future research directions and problems in production and commercialization. Overall, this study aims to elucidate the current development status of RNAi-based biopesticides and provide guidelines for future research.
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