1
|
Arahal DR, Bull CT, Christensen H, Chuvochina M, Dunlap C, del Carmen Montero-Calasanz M, Parker CT, Vandamme P, Ventosa A, Ventura S, Young P, Göker M. Judicial Opinion 130. Int J Syst Evol Microbiol 2024; 74:006414. [PMID: 38841989 PMCID: PMC11261725 DOI: 10.1099/ijsem.0.006414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 05/26/2024] [Indexed: 06/07/2024] Open
Abstract
Opinion 130 deals with a Request for an Opinion asking the Judicial Commission to clarify whether the genus name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate. The Request is approved and an answer is given. The name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate because it is a later homonym of the validly published cyanobacterial name Rhodococcus Hansgirg 1884. The Judicial Commission also clarifies that it has the means to resolve such cases by conserving a name over an earlier homonym. It is concluded that the name Rhodococcus Zopf 1891 (Approved Lists 1980) is significantly more important than the name Rhodococcus Hansgirg 1884 and therefore the former is conserved over the latter. This makes the name Rhodococcus Zopf 1891 (Approved Lists 1980) legitimate.
Collapse
Affiliation(s)
- David R. Arahal
- Departamento de Microbiología y Ecología, Universitat de València, Valencia, Spain
| | - Carolee T. Bull
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, 211 Buckhout Lab, University Park, PA 16802, USA
| | - Henrik Christensen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
| | - Maria Chuvochina
- The University of Queensland, School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, QLD 4072, Australia
| | - Christopher Dunlap
- Crop Bioprotection Research Unit, USDA/ARS/NCAUR, 1815 N. University St, 61604 Peoria, Illinois, USA
| | - Maria del Carmen Montero-Calasanz
- IFAPA Las Torres - Andalusian Institute of Agricultural and Fisheries Research and Training, Cra. Sevilla-Cazalla de la Sierra, 41200, Alcalá del Río, Sevilla, Spain
| | - Charles T. Parker
- Department of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Peter Vandamme
- BCCM/LMG, Laboratorium voor Microbiologie, Universiteit Gent (UGent) K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, C/. Prof. Garcia Gonzalez 2, ES-41012 Sevilla, Spain
| | - Stefano Ventura
- IRET-CNR, Research Institute on Terrestrial Ecosystems, National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, and NBCF, National Biodiversity Future Center, Palermo, Italy
| | - Peter Young
- Department of Biology, University of York, York YO10 5DD, UK
| | - Markus Göker
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstrasse 7B, D-38124 Braunschweig, Germany
| |
Collapse
|
2
|
Tian Q, Huang D. Association between urinary IPM3 and the presence of cardio-cerebrovascular diseases: a cross-sectional study. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27324-3. [PMID: 37225953 DOI: 10.1007/s11356-023-27324-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/26/2023] [Indexed: 05/26/2023]
Abstract
Our study aims to investigate the association of urinary IPM3 and cardio-cerebrovascular diseases (CVD) in general adults. A total of 1775 participants were enrolled from the National Health and Nutrition Examination Surveys. Urinary levels of IPM3 were measured by LC/MS as exposure to isoprene. The associations between isoprene exposure and the risk of CVD were evaluated by restricted cubic splines based on multivariable logistic regression models. The prevalence of CVD was significantly higher across IPM3 quartiles. Comparing with the lowest quartile, the highest quartile was associated with 2.47-fold risk of CVD (odds ratio: 2.47, 95% confidence interval: 1.40-4.39, P = 0.002). Restricted cubic spline confirmed that the levels of urinary IPM3 were linearly associated with cardio-cerebrovascular diseases, angina and heart attack, while nonlinearly related to CHF and CAD. In conclusion, the urinary IPM3, as a long-term isoprene exposure, was associated with the presence of cardio-cerebrovascular diseases, including CHF, CAD, angina, and heart attack.
Collapse
Affiliation(s)
- Qi Tian
- Department of Neurology, Geriatric Hospital of Nanjing Medical University, Jiangsu Province Official Hospital, Nanjing, China
| | - Danqing Huang
- Department of Neurology, Geriatric Hospital of Nanjing Medical University, Jiangsu Province Official Hospital, Nanjing, China.
| |
Collapse
|
3
|
Anaerobic Biohydrogenation of Isoprene by Acetobacterium wieringae Strain Y. mBio 2022; 13:e0208622. [PMID: 36342171 PMCID: PMC9765523 DOI: 10.1128/mbio.02086-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Isoprene is a ubiquitously distributed, biogenic, and climate-active organic compound. Microbial isoprene degradation in oxic environments is fairly well understood; however, studies exploring anaerobic isoprene metabolism remain scarce, with no isolates for study available. Here, we obtained an acetogenic isolate, designated Acetobacterium wieringae strain Y, which hydrogenated isoprene to a mixture of methyl-1-butenes at an overall rate of 288.8 ± 20.9 μM day-1 with concomitant acetate production at a rate of 478.4 ± 5.6 μM day-1. Physiological characterization demonstrated that isoprene was not utilized in a respiratory process; rather, isoprene promoted acetogenesis kinetically. Bioinformatic analysis and proteomics experiments revealed the expression of candidate ene-reductases responsible for isoprene biohydrogenation. Notably, the addition of isoprene to strain Y cultures stimulated the expression of proteins associated with the Wood-Ljungdahl pathway, indicating unresolved impacts of isoprene on carbon cycling and microbial ecology in anoxic environments (e.g., promoting CO2 plus H2 reductive acetogenesis while inhibiting methanogenesis). Our new findings advance understanding of microbial transformation of isoprene under anoxic conditions and suggest that anoxic environments are isoprene sinks. IMPORTANCE Isoprene is the most abundant, biologically generated, volatile organic compound on Earth, with estimated emissions in the same magnitude as methane. Nonetheless, a comprehensive knowledge of isoprene turnover in the environment is lacking, impacting global isoprene flux models and our understanding of the environmental fate and longevity of isoprene. A critical knowledge gap that has remained largely unexplored until recently is the microbiology and associated molecular mechanisms involved in the anaerobic biotransformation of isoprene. By integrating culture-dependent approaches with omics techniques, we isolated an acetogen, Acetobacterium wieringae strain Y, capable of anaerobic biohydrogenation of isoprene. We obtained the complete genome of strain Y, and proteomic experiments identified candidate ene-reductases for catalyzing the asymmetric reduction of the electronically activated carbon-carbon double bond of isoprene. We also demonstrated that isoprene biohydrogenation stimulates the expression of Wood-Ljungdahl pathway enzymes. This study emphasizes the ecological roles of specialized Acetobacterium on the natural cycling of isoprene in anoxic environments and the potential effects of isoprene biohydrogenation on acetogens and methanogens, which have implications for global climate change and bioenergy production.
Collapse
|
4
|
Singh A, Pandey AK, Dubey SK. Genome sequencing and in silico analysis of isoprene degrading monooxygenase enzymes of Sphingobium sp. BHU LFT2. J Biomol Struct Dyn 2022; 41:3821-3834. [PMID: 35380094 DOI: 10.1080/07391102.2022.2057360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The whole genome sequencing of a novel isoprene degrading strain of Sphingobium sp. BHU LFT2, its in silico analysis for identifying and characterizing enzymes, especially isoprene monooxygenases (IsoMO), which initiate the degradation process, and in vitro validation with cell extract of optimal temperature and pH and analysis for utilizing isoprene as the preferential substrate, were conducted. The most efficient monooxygenase was identified through comparative analyses using molecular docking followed by molecular dynamics simulation approach. The in silico results revealed high thermostability for most of the monooxygenases. Most potent monooxygenase with locus ID JQK15_20300 exhibiting high sequence similarity with known monooxygenases of isoprene-degrading Rhodococcus sp. LB1 and SC4 strains was identified. Interaction energy of -17.25 kJ/mol for JQK15_20300 with isoprene, was almost similar as that analysed for above-mentioned similar known counterparts, was exhibited by the molecular docking. Molecular dynamic simulation of 100 ns and free energy analysis of JQK15_20300 in the complex with isoprene gave persistent interaction of isoprene with JQK15_20300 during the simulation with high average binding energy of -47.13 kJ/mol thus proving higher affinity of JQK15_20300 for isoprene. The study revealed that the highly efficient isoprene degrading strain of Sphingobium sp. BHU LFT2 having effective monooxygenase could be utilized for large-scale applications including detoxification of air contaminated with isoprene in closed working systems.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Abhishek Singh
- Molecular Ecology Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Anand Kumar Pandey
- Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi, India
| | - Suresh Kumar Dubey
- Molecular Ecology Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| |
Collapse
|
5
|
Singh A, Kumar Pandey A, Kumar Dubey S. Biodegradation of isoprene by Arthrobacter sp. strain BHU FT2: Genomics-proteomics enabled novel insights. BIORESOURCE TECHNOLOGY 2021; 340:125634. [PMID: 34325393 DOI: 10.1016/j.biortech.2021.125634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/16/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
The bacterial degradation of isoprene is important for maintaining its atmospheric concentration in unpolluted environment. It may be possible to use natural isoprene degrading bacteria in engineered systems to eliminate or limit isoprene emissions from various sources. Biodegradation of isoprene by Arthrobacter sp. strain BHU FT2 was investigated. The genome was found to contain 4151545 bp long chromosome having 3747 coding genes, and coded potential isoprene degrading enzymes. The molecular docking of monooxygenases with isoprene displayed a higher binding energy (-4.59 kcal/mol) for WP_015938387.1 monooxygenase. Analysis of the identified monooxygenases with the known isoprene monooxygenases revealed 67% sequence identity of WP_015938387.1 (Locus tag JHV56_10705) monooxygenase of the considered strain with the OPX16961.1 monooxygenase of Gordonia sp. i37 isoprene degrading starin. These results provided a strong evidence for the high isoprene degrading potential of the Arthrobacter sp. BHU FT2 which could be efficiently exploited for isoprene degradation in large scale bio-filtration units.
Collapse
Affiliation(s)
- Abhishek Singh
- Molecular Ecology Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Anand Kumar Pandey
- Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi 284128, India
| | - Suresh Kumar Dubey
- Molecular Ecology Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
| |
Collapse
|
6
|
Yao X, Wang K, Zhang S, Liang S, Li K, Wang C, Zhang T, Li H, Wang J, Dong L, Yao Z. Degradation of the mixture of ethyl formate, propionic aldehyde, and acetone by Aeromonas salmonicida: A novel microorganism screened from biomass generated in the citric acid fermentation industry. CHEMOSPHERE 2020; 258:127320. [PMID: 32554008 DOI: 10.1016/j.chemosphere.2020.127320] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 05/30/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Microorganisms play important roles in the degradation of volatile organic compounds. Aeromonas salmonicida strain (AEP-3) generated from biomass in the citric acid fermentation industry was screened and subjected to denaturing gradient gel electrophoresis (DGGE) fingerprinting and 16S rDNA gene sequencing. The growth conditions of AEP-3 in Luria-Bertani broth were optimized at 25 °C and approximately pH 7. AEP-3 was used to degrade ethyl formate, propionic aldehyde, or acetone alone and their mixture. The concentrations of ethyl formate, propionic aldehyde, and acetone were below 7500, 600, and 800 mg L-1, respectively, and their maximum degradation efficiencies were 100%, 92.41%, and 34.75%. AEP-3 first degraded acetone and propionic aldehyde in the mixture, followed by ethyl formate. The degradation pathways of these organic compounds in the mixture and their substrate interactions during degradation were explored. Propionic aldehyde was first converted into propionic acid in the metabolic process and was involved in the subsequent carboxylic acid cycle. By contrast, ethyl formate was first hydrolyzed into formic acid and ethanol. Then, formic acid participated in the cyclic metabolism of carboxylic acid, whereas, ethanol was hydrolyzed into acetaldehyde and acetic acid through alcohol and aldehyde dehydrogenase. Additionally, acetone directly interacted with nitrate in the medium under the action of hydrogen ions and produced carbon dioxide, water, and nitrogen. Overall, this study provides a new degrading bacterium biodegradability toward the exhaust gas of citric acid fermentation.
Collapse
Affiliation(s)
- Xiaolong Yao
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China.
| | - Ke Wang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Shanshan Zhang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Shan Liang
- Beijing Engineering and Technology Research Center of Food Additives (Beijing Technology and Business University), Beijing, China
| | - Ke Li
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Chun Wang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Tingting Zhang
- College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Hailong Li
- School of Energy Science and Engineering, Central South University, Changsha, 410083, China
| | | | - Liming Dong
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Zhiliang Yao
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, China.
| |
Collapse
|
7
|
Murrell JC, McGenity TJ, Crombie AT. Microbial metabolism of isoprene: a much-neglected climate-active gas. MICROBIOLOGY-SGM 2020; 166:600-613. [PMID: 32441612 PMCID: PMC7657509 DOI: 10.1099/mic.0.000931] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The climate-active gas isoprene is the major volatile produced by a variety of trees and is released into the atmosphere in enormous quantities, on a par with global emissions of methane. While isoprene production in plants and its effect on atmospheric chemistry have received considerable attention, research into the biological isoprene sink has been neglected until recently. Here, we review current knowledge on the sources and sinks of isoprene and outline its environmental effects. Focusing on degradation by microbes, many of which are able to use isoprene as the sole source of carbon and energy, we review recent studies characterizing novel isoprene degraders isolated from soils, marine sediments and in association with plants. We describe the development and use of molecular methods to identify, quantify and genetically characterize isoprene-degrading strains in environmental samples. Finally, this review identifies research imperatives for the further study of the environmental impact, ecology, regulation and biochemistry of this interesting group of microbes.
Collapse
Affiliation(s)
- J Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Terry J McGenity
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Andrew T Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| |
Collapse
|
8
|
Dawson RA, Larke-Mejía NL, Crombie AT, Ul Haque MF, Murrell JC. Isoprene Oxidation by the Gram-Negative Model bacterium Variovorax sp. WS11. Microorganisms 2020; 8:E349. [PMID: 32121431 PMCID: PMC7143210 DOI: 10.3390/microorganisms8030349] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 01/19/2023] Open
Abstract
Plant-produced isoprene (2-methyl-1,3-butadiene) represents a significant portion of global volatile organic compound production, equaled only by methane. A metabolic pathway for the degradation of isoprene was first described for the Gram-positive bacterium Rhodococcus sp. AD45, and an alternative model organism has yet to be characterised. Here, we report the characterisation of a novel Gram-negative isoprene-degrading bacterium, Variovorax sp. WS11. Isoprene metabolism in this bacterium involves a plasmid-encoded iso metabolic gene cluster which differs from that found in Rhodococcus sp. AD45 in terms of organisation and regulation. Expression of iso metabolic genes is significantly upregulated by both isoprene and epoxyisoprene. The enzyme responsible for the initial oxidation of isoprene, isoprene monooxygenase, oxidises a wide range of alkene substrates in a manner which is strongly influenced by the presence of alkyl side-chains and differs from other well-characterised soluble diiron monooxygenases according to its response to alkyne inhibitors. This study presents Variovorax sp. WS11 as both a comparative and contrasting model organism for the study of isoprene metabolism in bacteria, aiding our understanding of the conservation of this biochemical pathway across diverse ecological niches.
Collapse
Affiliation(s)
- Robin A. Dawson
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
| | - Nasmille L. Larke-Mejía
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
| | - Andrew T. Crombie
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK;
| | - Muhammad Farhan Ul Haque
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54000, Pakistan;
| | - J. Colin Murrell
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK; (R.A.D.); (N.L.L.-M.)
| |
Collapse
|
9
|
Lienkamp AC, Heine T, Tischler D. Glutathione: A powerful but rare cofactor among Actinobacteria. ADVANCES IN APPLIED MICROBIOLOGY 2020; 110:181-217. [PMID: 32386605 DOI: 10.1016/bs.aambs.2019.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glutathione (γ-l-glutamyl-l-cysteinylglycine, GSH) is a powerful cellular redox agent. In nature only the l,l-form is common among the tree of life. It serves as antioxidant or redox buffer system, protein regeneration and activation by interaction with thiol groups, unspecific reagent for conjugation during detoxification, marker for amino acid or peptide transport even through membranes, activation or solubilization of compounds during degradative pathways or just as redox shuttle. However, the role of GSH production and utilization in bacteria is more complex and especially little is known for the Actinobacteria. Some recent reports on GSH use in degradative pathways came across and this is described herein. GSH is used by transferases to activate and solubilize epoxides. It allows funneling epoxides as isoprene oxide or styrene oxide into central metabolism. Thus, the distribution of GSH synthesis, recycling and application among bacteria and especially Actinobacteria are highlighted including the pathways and contributing enzymes.
Collapse
Affiliation(s)
- Anna C Lienkamp
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Thomas Heine
- Environmental Microbiology, Faculty of Chemistry and Physics, TU Bergakademie Freiberg, Freiberg, Germany
| | - Dirk Tischler
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| |
Collapse
|
10
|
Yang R, Zhang G, Li S, Moazeni F, Li Y, Wu Y, Zhang W, Chen T, Liu G, Zhang B, Wu X. Degradation of crude oil by mixed cultures of bacteria isolated from the Qinghai-Tibet plateau and comparative analysis of metabolic mechanisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:1834-1847. [PMID: 30456621 DOI: 10.1007/s11356-018-3718-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
This study investigates the biodegradation of crude oil by a mixed culture of bacteria isolated from the Qinghai-Tibet plateau using gas chromatography-mass spectrometer (GC-MS) and the gravimetric method. The results showed that a mixed culture has a stronger ability to degrade hydrocarbon than pure cultures. Once both Nocardia soli Y48 and Rhodococcus erythropolis YF28-1 (8) were present in a culture, the culture demonstrated the highest crude oil removal efficiency of almost 100% after 10 days of incubation at 20 °C. Moreover, further analysis of the degradation mechanisms used by the above strains, which revealed utilization of different n-alkane substrates, indicated the diversity of evolution and variations in different strains, as well as the importance of multiple metabolic mechanisms for alkane degradation. Therefore, it is concluded that a mixed culture of Y48 and YF28-1 (8) strains can provide a more effective method for bioremediation of hydrocarbon-contaminated soil in permafrost regions.
Collapse
Affiliation(s)
- Ruiqi Yang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Gaosen Zhang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
| | - Shiweng Li
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
- School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Faegheh Moazeni
- School of Science Engineering and Technology, Penn State Harrisburg University, Middletown, PA, 17057, USA
| | - Yunshi Li
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Yongna Wu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
- University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Wei Zhang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
| | - Tuo Chen
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China.
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Guangxiu Liu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China.
| | - Binglin Zhang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
| | - Xiukun Wu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China
| |
Collapse
|
11
|
Abstract
Isoprene is a climate-active gas, produced in huge amounts by trees, yet we know little about its biogeochemical cycle. Bacteria able to grow on isoprene have been isolated from soils and sediments, but the phyllosphere, the principal isoprene source, has remained unexplored. Using targeted cultivation-independent techniques, we show that the phyllosphere of an isoprene-emitting tree contains a diverse and active isoprene-degrading population. We reconstruct the genome of an isoprene-degrading Variovorax strain and show that it contains a functional isoprene monooxygenase. This detailed study targets isoprene degraders from the phyllosphere, applies metaomics to isoprene degradation, and isolates and sequences an isoprene-degrading member of the Proteobacteria. The climate-active gas isoprene (2-methyl-1,3-butadiene) is released to the atmosphere in huge quantities, almost equaling that of methane, yet we know little about the biological cycling of isoprene in the environment. Although bacteria capable of growth on isoprene as the sole source of carbon and energy have previously been isolated from soils and sediments, no microbiological studies have targeted the major source of isoprene and examined the phyllosphere of isoprene-emitting trees for the presence of degraders of this abundant carbon source. Here, we identified isoprene-degrading bacteria in poplar tree-derived microcosms by DNA stable isotope probing. The genomes of isoprene-degrading taxa were reconstructed, putative isoprene metabolic genes were identified, and isoprene-related gene transcription was analyzed by shotgun metagenomics and metatranscriptomics. Gram-positive bacteria of the genus Rhodococcus proved to be the dominant isoprene degraders, as previously found in soil. However, a wider diversity of isoprene utilizers was also revealed, notably Variovorax, a genus not previously associated with this trait. This finding was confirmed by expression of the isoprene monooxygenase from Variovorax in a heterologous host. A Variovorax strain that could grow on isoprene as the sole carbon and energy source was isolated. Analysis of its genome confirmed that it contained isoprene metabolic genes with an identical layout and high similarity to those identified by DNA-stable isotope probing and metagenomics. This study provides evidence of a wide diversity of isoprene-degrading bacteria in the isoprene-emitting tree phyllosphere and greatly enhances our understanding of the biodegradation of this important metabolite and climate-active gas.
Collapse
|