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Kim YJ, Choi HS, Park DH. Persistence and viable but non-culturable state induced by streptomycin in Erwinia amylovora. Front Microbiol 2024; 15:1346300. [PMID: 38450169 PMCID: PMC10914980 DOI: 10.3389/fmicb.2024.1346300] [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] [Received: 11/29/2023] [Accepted: 02/08/2024] [Indexed: 03/08/2024] Open
Abstract
Persister cell and viable but non-culturable (VBNC) state of bacteria are survival strategies against antibiotics and various environmental stresses, respectively, but they tend to be ignored in agriculture fields, even though bacteria can regain their abilities to survive and produce disease once those stresses disappear. This study was carried out to determine whether persister cell and VBNC state in Erwinia amylovora are present after exposures to streptomycin, the length of their persistence, and the steps needed to decrease the inoculum. Persister cells were observed using biphasic killed growth curve for 4-8 h when the late stationary phase cells of E. amylovora were cultured in liquid medium containing streptomycin. This state was maintained for up to 12 h based on the colony forming units (CFUs) of the colonies that grew on the mannitol glutamate yeast extract (MGY) medium after streptomycin was removed. The CFUs on the MGY medium were lower than the total count determined using the LIVE/DEAD Kit, suggesting that persister cells and VBNC state might co-exist for up to 12 h after exposure to streptomycin. However, after 12 h, E. amylovora cells did not continue to grow on the medium for 9 days, suggesting that they entered a VBNC state at that time and remained in a persistent state. In addition, based on the Redox Sensor Green staining method, the presence of both states was confirmed for up to 12 h, and only then did the VBNC state became apparent. Furthermore, persister cells were observed for up to 24 h, and damaged cells reduced when E. amylovora cells were culture in distilled water with streptomycin, indicating that the uptake of lower nutrients in E. amylovora led to prolonged persister cells and VBNC state, which are more likely to survive after streptomycin treatments. The addition of sucrose and oxytetracycline to distilled water containing streptomycin reduced persister cells than other sources did. Thus, to inhibit the spread of fire blight, management techniques must consider the hazards of using streptomycin treatments that induce dormancy, such as persister cells and VBNC state, beyond the development of resistant strain.
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Affiliation(s)
- Yeon Ju Kim
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
| | - Hyun Seo Choi
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
| | - Duck Hwan Park
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
- Plant Medicine Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon-si, Republic of Korea
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Dhar BC, Delgado Santander R, Aćimović SG. Improved Canker Processing and Viability Droplet Digital PCR Allow Detection of Erwinia amylovora Viable Nonculturable Cells in Apple Bark. Microorganisms 2024; 12:376. [PMID: 38399780 PMCID: PMC10893025 DOI: 10.3390/microorganisms12020376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
The bacterium Erwinia amylovora causes fire blight and continues to threaten global commercial apple and pear production. Conventional microbiology techniques cannot accurately determine the presence of live pathogen cells in fire blight cankers. Several factors may prevent E. amylovora from growing on solid culture media, including competing microbiota and the release of bacterial-growth-inhibitory compounds by plant material during sample processing. We previously developed a canker processing methodology and a chip-based viability digital PCR (v-dPCR) assay using propidium monoazide (PMA) to bypass these obstacles. However, sample analysis was still time-consuming and physically demanding. In this work, we improved the previous protocol using an automatic tissue homogenizer and transferred the chip-based v-dPCR to the BioRad QX200 droplet dPCR (ddPCR) platform. The improved sample processing method allowed the simultaneous, fast, and effortless processing of up to six samples. Moreover, the transferred v-ddPCR protocol was compatible with the same PMA treatment and showed a similar dynamic range, from 7.2 × 102 to 7.6 × 107 cells mL-1, as the previous v-dPCR. Finally, the improved protocol allowed, for the first time, the detection of E. amylovora viable but nonculturable (VBNC) cells in cankers and bark tissues surrounding cankers. Our v-ddPCR assay will enable new ways to evaluate resistant pome fruit tree germplasm, further dissect the E. amylovora life cycle, and elucidate E. amylovora physiology, epidemiology, and new options for canker management.
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Affiliation(s)
- Bidhan Chandra Dhar
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, 595 Laurel Grove Rd, Winchester, VA 22602, USA;
| | - Ricardo Delgado Santander
- Irrigated Agriculture Research and Extension Center, College of Agricultural, Human and Natural Resource Sciences, Washington State University, Prosser, WA 99350, USA;
| | - Srđan G. Aćimović
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, 595 Laurel Grove Rd, Winchester, VA 22602, USA;
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Pazos-Rojas LA, Cuellar-Sánchez A, Romero-Cerón AL, Rivera-Urbalejo A, Van Dillewijn P, Luna-Vital DA, Muñoz-Rojas J, Morales-García YE, Bustillos-Cristales MDR. The Viable but Non-Culturable (VBNC) State, a Poorly Explored Aspect of Beneficial Bacteria. Microorganisms 2023; 12:39. [PMID: 38257865 PMCID: PMC10818521 DOI: 10.3390/microorganisms12010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024] Open
Abstract
Many bacteria have the ability to survive in challenging environments; however, they cannot all grow on standard culture media, a phenomenon known as the viable but non-culturable (VBNC) state. Bacteria commonly enter the VBNC state under nutrient-poor environments or under stressful conditions. This review explores the concept of the VBNC state, providing insights into the beneficial bacteria known to employ this strategy. The investigation covers different chemical and physical factors that can induce the latency state, cell features, and gene expression observed in cells in the VBNC state. The review also covers the significance and applications of beneficial bacteria, methods of evaluating bacterial viability, the ability of bacteria to persist in environments associated with higher organisms, and the factors that facilitate the return to the culturable state. Knowledge about beneficial bacteria capable of entering the VBNC state remains limited; however, beneficial bacteria in this state could face adverse environmental conditions and return to a culturable state when the conditions become suitable and continue to exert their beneficial effects. Likewise, this unique feature positions them as potential candidates for healthcare applications, such as the use of probiotic bacteria to enhance human health, applications in industrial microbiology for the production of prebiotics and functional foods, and in the beer and wine industry. Moreover, their use in formulations to increase crop yields and for bacterial bioremediation offers an alternative pathway to harness their beneficial attributes.
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Affiliation(s)
- Laura Abisaí Pazos-Rojas
- Faculty of Stomatology, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico; (L.A.P.-R.); (A.R.-U.)
- Monterrey Institute of Technology, School of Engineering and Sciences, Monterrey 64700, Mexico; (A.C.-S.); (A.L.R.-C.); (D.A.L.-V.)
| | - Alma Cuellar-Sánchez
- Monterrey Institute of Technology, School of Engineering and Sciences, Monterrey 64700, Mexico; (A.C.-S.); (A.L.R.-C.); (D.A.L.-V.)
| | - Ana Laura Romero-Cerón
- Monterrey Institute of Technology, School of Engineering and Sciences, Monterrey 64700, Mexico; (A.C.-S.); (A.L.R.-C.); (D.A.L.-V.)
| | - América Rivera-Urbalejo
- Faculty of Stomatology, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico; (L.A.P.-R.); (A.R.-U.)
| | - Pieter Van Dillewijn
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| | - Diego Armando Luna-Vital
- Monterrey Institute of Technology, School of Engineering and Sciences, Monterrey 64700, Mexico; (A.C.-S.); (A.L.R.-C.); (D.A.L.-V.)
| | - Jesús Muñoz-Rojas
- Ecology and Survival of Microorganisms Group, Laboratory of Microbial Molecular Ecology (LEMM), Center for Research in Microbiological Sciences, Institute of Sciences, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico;
| | - Yolanda Elizabeth Morales-García
- Ecology and Survival of Microorganisms Group, Laboratory of Microbial Molecular Ecology (LEMM), Center for Research in Microbiological Sciences, Institute of Sciences, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico;
- Faculty of Biological Sciences, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico
| | - María del Rocío Bustillos-Cristales
- Ecology and Survival of Microorganisms Group, Laboratory of Microbial Molecular Ecology (LEMM), Center for Research in Microbiological Sciences, Institute of Sciences, Meritorious Autonomous University of Puebla (BUAP), Puebla 72570, Mexico;
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de Pedro-Jové R, Corral J, Rocafort M, Puigvert M, Azam FL, Vandecaveye A, Macho AP, Balsalobre C, Coll NS, Orellano E, Valls M. Gene expression changes throughout the life cycle allow a bacterial plant pathogen to persist in diverse environmental habitats. PLoS Pathog 2023; 19:e1011888. [PMID: 38113281 PMCID: PMC10763947 DOI: 10.1371/journal.ppat.1011888] [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: 08/31/2023] [Revised: 01/03/2024] [Accepted: 12/07/2023] [Indexed: 12/21/2023] Open
Abstract
Bacterial pathogens exhibit a remarkable ability to persist and thrive in diverse ecological niches. Understanding the mechanisms enabling their transition between habitats is crucial to control dissemination and potential disease outbreaks. Here, we use Ralstonia solanacearum, the causing agent of the bacterial wilt disease, as a model to investigate pathogen adaptation to water and soil, two environments that act as bacterial reservoirs, and compare this information with gene expression in planta. Gene expression in water resembled that observed during late xylem colonization, with an intriguing induction of the type 3 secretion system (T3SS). Alkaline pH and nutrient scarcity-conditions also encountered during late infection stages-were identified as the triggers for this T3SS induction. In the soil environment, R. solanacearum upregulated stress-responses and genes for the use of alternate carbon sources, such as phenylacetate catabolism and the glyoxylate cycle, and downregulated virulence-associated genes. We proved through gain- and loss-of-function experiments that genes associated with the oxidative stress response, such as the regulator OxyR and the catalase KatG, are key for bacterial survival in soil, as their deletion cause a decrease in culturability associated with a premature induction of the viable but non culturable state (VBNC). This work identifies essential factors necessary for R. solanacearum to complete its life cycle and is the first comprehensive gene expression analysis in all environments occupied by a bacterial plant pathogen, providing valuable insights into its biology and adaptation to unexplored habitats.
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Affiliation(s)
- Roger de Pedro-Jové
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Jordi Corral
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Mercedes Rocafort
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Marina Puigvert
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Fàtima Latif Azam
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Agustina Vandecaveye
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-UNR-CONICET), Rosario, Santa Fe, Argentina
| | - Alberto P. Macho
- Shanghai Centre for Plant Stress Biology, CAS Centre for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Elena Orellano
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-UNR-CONICET), Rosario, Santa Fe, Argentina
| | - Marc Valls
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
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Etminani F, Barzegari E. Virtual screening of natural ligands from five resources to target Ralstonia solanacearum polygalacturonase and endoglucanase. 3 Biotech 2023; 13:261. [PMID: 37404365 PMCID: PMC10315359 DOI: 10.1007/s13205-023-03683-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023] Open
Abstract
The present computational study explores novel herbal compounds with potent inhibitory activity against polygalacturonase (PG) and endoglucanase (EG), the extracellular cell wall-degrading enzymes of Ralstonia solanacearum causing crops' bacterial wilt. Phytocompounds of Rosmarinus officinalis L., Coriandrum sativum L., Ocimum basilicum, Cymbopogon citratus, and Thymus vulgaris were first checked to be pharmacokinetically safe and nontoxic. The ligands were then docked to predicted and validated structural models of PG and EG. Molecular dynamic simulations were performed to ensure the dynamic stability of protein-ligand complexes. Carvone and citronellyl acetate were identified to have the best docking energy in binding and inhibiting PG and EG, respectively. In molecular dynamics, root-mean-square deviations of PG-Carvone and EG-Citronellyl acetate complexes indicated the high stability of the ligands in their corresponding cavities. Root-mean-square fluctuations of both proteins indicated unchanged mobility of the binding site residues due to a stable interaction with their ligands. Functional groups on both ligands contributed to the formation of hydrogen bonds with their respective proteins, which were preserved throughout the simulation time. The nonpolar energy component was revealed to significantly contribute to the stability of the docked protein-ligand complexes. Overall, our findings imply the high capability of Carvone and Citronellyl acetate as strong pesticides against the R. solanacearum-caused wilt. This study highlighted the potential of natural ligands in controlling the agricultural bacterial infections, as well as the utility of computational screening techniques in discovering appropriate and potent lead compounds. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03683-z.
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Affiliation(s)
- Faegheh Etminani
- Department of Plant Protection, University of Kurdistan, Sanandaj, Iran
| | - Ebrahim Barzegari
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
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6
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Bai K, Xu X, Wang X, Li Y, Yu C, Jiang N, Li J, Luo L. Transcriptional profiling of Xanthomonas campestris pv. campestris in viable but nonculturable state. BMC Genomics 2023; 24:105. [PMID: 36894875 PMCID: PMC9999588 DOI: 10.1186/s12864-023-09200-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 02/21/2023] [Indexed: 03/11/2023] Open
Abstract
BACKGROUND Xanthomonas campestris pv. campestris (Xcc) is an important seed-borne plant pathogenic bacteria that can cause a serious threat to cruciferous crops. Bacteria can enter into the viable but non-culturable (VBNC) state under stress conditions, and cause potential risks to agricultural production because the VBNC bacterial cells will evade culture-based detection. However, little is known about the mechanism of VBNC. Our previous study showed that Xcc could be induced into VBNC state by copper ion (Cu2+). RESULTS Here, RNA-seq was performed to explore the mechanism of VBNC state. The results indicated that expression profiling was changed dramatically in the different VBNC stages (0 d, 1 d, 2 d and 10 d). Moreover, metabolism related pathways were enriched according to COG, GO and KEGG analysis of differentially expressed genes (DEGs). The DEGs associated with cell motility were down-regulated, whereas pathogenicity related genes were up-regulated. This study revealed that the high expression of genes related to stress response could trigger the active cells to VBNC state, while the genes involved in transcription and translation category, as well as transport and metabolism category, were ascribed to maintaining the VBNC state. CONCLUSION This study summarized not only the related pathways that might trigger and maintain VBNC state, but also the expression profiling of genes in different survival state of bacteria under stress. It provided a new kind of gene expression profile and new ideas for studying VBNC state mechanism in X. campestris pv. campestris.
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Affiliation(s)
- Kaihong Bai
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, People's Republic of China.,Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Xiaoli Xu
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Xudong Wang
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Yao Li
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Chengxuan Yu
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Na Jiang
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Jianqiang Li
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Laixin Luo
- Department of Plant Pathology, Key Laboratory of Seed Disease Testing and Control, MOA Key Lab of Pest Monitoring and Green Management, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China.
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Han Z, Lin Q, Zhang S, Zhou X, Li S, Sun F, Shen C, Su X. High PCBs mineralization capability of a resuscitated strain Bacillus sp. LS1 and its survival in PCB-contaminated soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159224. [PMID: 36206912 DOI: 10.1016/j.scitotenv.2022.159224] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Polychlorinated biphenyl (PCB)-degrading strains resuscitated by resuscitation promoting factor (Rpf) enlarged pure degraders to screen effective bio-inoculants for soil bioaugmentation. In this study, whole-genome analysis and PCB-degrading performance of a resuscitated strain LS1 were investigated. Importantly, the persistence and the physiological response of soil-inoculated LS1 were checked. The results indicate that the Bacillus sp. strain LS1 possessed the potential to degrade polycyclic aromatic compounds. LS1 exhibited better performance in degrading PCBs 18 and 52, but lower PCB 77 degradation capability. At PCBs concentration of 10 mg/L, the degradation efficiencies of PCBs 18, 52 and 77 within 96 h were 62.8 %, 59.6 % and 39.8 %, respectively. Combined the bph genes and metabolites detected, as well as the genes found in the genome, the abilities of LS1 for oxidative dehalogenation and mineralization of PCBs via HOPDA-benzoate-protocatechuate-β-ketoadipate pathway were determined. Notably, LS1 can still maintain survival and culturable state after inoculation into PCB-contaminated soil for 70 days. This is the first report to demonstrate the fate of resuscitated strain when used as soil bio-inoculant, which revealed the necessity and feasibility of using resuscitated strains to enhance bioremediation of PCB-contaminated soils.
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Affiliation(s)
- Zhen Han
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Qihua Lin
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Shusheng Zhang
- The Management Center of Wuyanling National Natural Reserve in Zhejiang, Wenzhou 325500, China
| | - Xinru Zhou
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Si Li
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Faqian Sun
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Chaofeng Shen
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xiaomei Su
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
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Host plant physiological transformation and microbial population heterogeneity as important determinants of the Soft Rot Pectobacteriaceae-plant interactions. Semin Cell Dev Biol 2023; 148-149:33-41. [PMID: 36621443 DOI: 10.1016/j.semcdb.2023.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
Pectobacterium and Dickeya species belonging to the Soft Rot Pectobacteriaceae (SRP) are one of the most devastating phytopathogens. They degrade plant tissues by producing an arsenal of plant cell wall degrading enzymes. However, SRP-plant interactions are not restricted to the production of these "brute force" weapons. Additionally, these bacteria apply stealth behavior related to (1) manipulation of the host plant via induction of susceptible responses and (2) formation of heterogeneous populations with functionally specialized cells. Our review aims to summarize current knowledge on SRP-induced plant susceptible responses and on the heterogeneity of SRP populations. The review shows that SRP are capable of adjusting the host's hormonal balance, inducing host-mediated plant cell wall modification, promoting iron assimilation by the host, stimulating the accumulation of reactive oxygen species and host cell death, and activating the synthesis of secondary metabolites that are ineffective in limiting disease progression. By this means, SRP facilitate host plant susceptibility. During host colonization, SRP populations produce various functionally specialized cells adapted for enhanced virulence, increased resistance, motility, vegetative growth, or colonization of the vascular system. This enables SRP to perform self-contradictory tasks, which benefits a population's overall fitness in various environments, including host plants. Such stealthy tactical actions facilitate plant-SRP interactions and disease progression.
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Hayes MM, Dewberry RJ, Babujee L, Moritz R, Allen C. Validating Methods To Eradicate Plant-Pathogenic Ralstonia Strains Reveals that Growth In Planta Increases Bacterial Stress Tolerance. Microbiol Spectr 2022; 10:e0227022. [PMID: 36453936 PMCID: PMC9769772 DOI: 10.1128/spectrum.02270-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/14/2022] [Indexed: 12/03/2022] Open
Abstract
Plant-pathogenic bacteria in the Ralstonia solanacearum species complex (RSSC) cause highly destructive bacterial wilt disease of diverse crops. Wilt disease prevention and management is difficult because RSSC persists in soil, water, and plant material. Growers need practical methods to kill these pathogens in irrigation water, a common source of disease outbreaks. Additionally, the R. solanacearum race 3 biovar 2 (R3bv2) subgroup is a quarantine pest in many countries and a highly regulated select agent pathogen in the United States. Plant protection officials and researchers need validated protocols to eradicate R3bv2 for regulatory compliance. To meet these needs, we measured the survival of four R3bv2 and three phylotype I RSSC strains following treatment with hydrogen peroxide, stabilized hydrogen peroxide (Huwa-San), active chlorine, heat, UV radiation, and desiccation. No surviving RSSC cells were detected after cultured bacteria were exposed for 10 min to 400 ppm hydrogen peroxide, 50 ppm Huwa-San, 50 ppm active chlorine, or temperatures above 50°C. RSSC cells on agar plates were eradicated by 30 s of UV irradiation and killed by desiccation on most biotic and all abiotic surfaces tested. RSSC bacteria did not survive the cell lysis steps of four nucleic acid extraction protocols. However, bacteria in planta were more difficult to kill. Stems of infected tomato plants contained a subpopulation of bacteria with increased tolerance of heat and UV light, but not oxidative stress. This result has significant management implications. We demonstrate the utility of these protocols for compliance with select agent research regulations and for management of a bacterial wilt outbreak in the field. IMPORTANCE Bacteria in the Ralstonia solanacearum species complex (RSSC) are globally distributed and cause destructive vascular wilt diseases of many high-value crops. These aggressive pathogens spread in diseased plant material and via contaminated soil, tools, and irrigation water. A subgroup of the RSSC, race 3 biovar 2, is a European and Canadian quarantine pathogen and a U.S. select agent subject to stringent and constantly evolving regulations intended to prevent pathogen introduction or release. We validated eradication and inactivation methods that can be used by (i) growers seeking to disinfest water and manage bacterial wilt disease outbreaks, (ii) researchers who must remain in compliance with regulations, and (iii) regulators who are expected to define containment practices. Relevant to all these stakeholders, we show that while cultured RSSC cells are sensitive to relatively low levels of oxidative chemicals, desiccation, and heat, more aggressive treatment, such as autoclaving or incineration, is required to eradicate plant-pathogenic Ralstonia growing inside plant material.
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Affiliation(s)
- Madeline M. Hayes
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Ronnie J. Dewberry
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Lavanya Babujee
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Rebecca Moritz
- Select Agent Program, Environment, Health, and Safety, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin—Madison, Madison, Wisconsin, USA
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Kong HG, Sang MK, An JH, Kim S, Jin YJ, Song J. Changes in the Composition and Microbial Community of the Pepper Rhizosphere in Field with Bacterial Wilt Disease. THE PLANT PATHOLOGY JOURNAL 2022; 38:692-699. [PMID: 36503199 PMCID: PMC9742803 DOI: 10.5423/ppj.nt.09.2022.0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Bacterial wilt caused by Ralstonia solanacearum is considered one of the most harmful diseases of pepper plants. Recently, research on plant disease control through the rhizosphere microbiome has been actively conducted. In this study, the relationship with disease occurrence between the neighboring plant confirmed by analyzing the physicochemical properties of the rhizosphere soil and changes in the microbial community. The results confirmed that the microbial community changes significantly depending on the organic matters, P2O5, and clay in the soil. Despite significant differences in microbial communities according to soil composition, Actinobacteriota at the phylum level was higher in healthy plant rhizosphere (mean of relative abundance, D: 8.05 ± 1.13; H: 10.06 ± 1.59). These results suggest that Actinobacteriota may be associated with bacterial wilt disease. In this study, we present basic information for constructing of healthy soil in the future by presenting the major microbial groups that can suppress bacterial wilt.
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Affiliation(s)
- Hyun Gi Kong
- Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 28644,
Korea
| | - Mee Kyung Sang
- Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Korea
| | - Ju Hee An
- Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Korea
| | - Songhwa Kim
- Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Korea
| | - Yong Ju Jin
- Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Korea
| | - Jaekyeong Song
- Agricultural Microbiology Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365,
Korea
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11
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The Role of RelA and SpoT on ppGpp Production, Stress Response, Growth Regulation, and Pathogenicity in Xanthomonas campestris pv. campestris. Microbiol Spectr 2021; 9:e0205721. [PMID: 34935430 PMCID: PMC8693919 DOI: 10.1128/spectrum.02057-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The alarmone ppGpp plays an important role in the survival of bacteria by triggering the stringent response when exposed to environmental stress. Although Xanthomonas campestris pv. campestris (Xcc), which causes black rot disease in crucifers, is a representative species of Gram-negative phytopathogenic bacteria, relatively little is known regarding the factors influencing the stringent response in this species. However, previous studies in other Gram-negative bacteria have indicated that RelA and SpoT play a critical role in ppGpp synthesis. The current study found that these proteins also had an important role in Xcc, with a ΔrelAΔspoT double mutant being unable to produce ppGpp, resulting in changes to phenotype including reduced production of exopolysaccharides (EPS), exoenzymes, and biofilm, as well the loss of swarming motility and pathogenicity. The ppGpp-deficient mutant also exhibited greater sensitivity to environment stress, being almost incapable of growth on modified minimal medium (mMM) and having a much greater propensity to enter the viable but nonculturable (VBNC) state in response to oligotrophic conditions (0.85% NaCl). These findings much advance our understanding of the role of ppGpp in the biology of Xcc and could have important implications for more effective management of this important pathogen. IMPORTANCEXanthomonas campestris pv. campestris (Xcc) is a typical seedborne phytopathogenic bacterium that causes large economic losses worldwide, and this is the first original research article to investigate the role of ppGpp in this important species. Here, we revealed the function of RelA and SpoT in ppGpp production, physiology, pathogenicity, and stress resistance in Xcc. Most intriguingly, we found that ppGpp levels and downstream ppGpp-dependent phenotypes were mediated predominantly by SpoT, with RelA having only a supplementary role. Taken together, the results of the current study provide new insight into the role of ppGpp in the biology of Xcc, which could also have important implications for the role of ppGpp in the survival and pathogenicity of other pathogenic bacteria.
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12
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Zhou X, Wang Y, Li C, Xu Y, Su X, Yang T, Zhang X. Differential Expression Pattern of Pathogenicity-Related Genes of Ralstonia pseudosolanacearum YQ Responding to Tissue Debris of Casuarina equisetifolia. PHYTOPATHOLOGY 2021; 111:1918-1926. [PMID: 33822646 DOI: 10.1094/phyto-11-20-0490-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ralstonia solanacearum species complex (RSSC) contains a group of destructive plant pathogenic bacteria, causing bacterial wilt of >200 species of crops and trees, such as Casuarina equisetifolia, worldwide. RSSC can survive in the soil environment for a long time and start infection after activation by host plants. This study conducted a transcriptome analysis on the expression pattern of the pathogenicity-related genes of a new isolated RSSC strain YQ (Ralstonia pseudosolanacearum phylotype I-16) in response to C. equisetifolia cladophyll (a branch of a stem that resembles and functions as a leaf) and root debris under in vitro culture. The cladophyll debris induced more genes up-regulated than the root debris, including pathogenicity-related genes involved in motility, effectors, type III secretion systems, quorum sensing, and plant cell wall degradation. Besides, many differentially expressed genes were related to transcriptional regulator such as cyclic dimeric guanosine monophosphate. Moreover, the cultures with cladophyll debris induced a faster wilting in bioassays, and the cell swimming was enhanced by cladophyll exudate. C. equisetifolia cladophylls could activate the expression of pathogenicity-related genes of strain YQ and accelerate infection. Our findings suggest that litterfall management in C. equisetifolia forests, or even other plantations, should receive attention to prevent the induction of bacterial wilt disease caused by RSSC.
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Affiliation(s)
- Xiang Zhou
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Yue Wang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Chuqiao Li
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Yuanyou Xu
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Xiu Su
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Tian Yang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Xinqi Zhang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
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13
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Wang KH, Zheng DH, Yuan GQ, Lin W, Li QQ. A yceI Gene Involves in the Adaptation of Ralstonia solanacearum to Methyl Gallate and Other Stresses. Microorganisms 2021; 9:microorganisms9091982. [PMID: 34576877 PMCID: PMC8472277 DOI: 10.3390/microorganisms9091982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
Ralstonia solanacearum is a plant-pathogenic bacterium causing plant bacterial wilt, and can be strongly inhibited by methyl gallate (MG). Our previous transcriptome sequencing of MG-treated R. solanacearum showed that the yceI gene AVT05_RS03545 of Rs-T02 was up-regulated significantly under MG stress. In this study, a deletion mutant (named DM3545) and an over-expression strain (named OE3545) for yceI were constructed to confirm this hypothesis. No significant difference was observed among the growth of wild-type strain, DM3545 and OE3545 strains without MG treatment. Mutant DM3545 showed a lower growth ability than that of the wild type and OE3545 strains under MG treatment, non-optimal temperature, or 1% NaCl. The ability of DM3545 for rhizosphere colonization was lower than that of the wild-type and OE3545 strains. The DM3545 strain showed substantially reduced virulence toward tomato plants than its wild-type and OE3545 counterpart. Moreover, DM3545 was more sensitive to MG in plants than the wild-type and OE3545 strains. These results suggest that YceI is involved in the adaptability of R. solanacearum to the presence of MG and the effect of other tested abiotic stresses. This protein is also possibly engaged in the virulence potential of R. solanacearum.
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Affiliation(s)
| | | | | | | | - Qi-Qin Li
- Correspondence: (D.-H.Z.); (Q.-Q.L.)
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14
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Nakahara H, Mori K, Mori T, Matsuzoe N. Induction of spontaneous phenotype conversion in Ralstonia solanacearum by addition of iron compounds in liquid medium. J Microbiol Methods 2021; 186:106233. [PMID: 33965508 DOI: 10.1016/j.mimet.2021.106233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022]
Abstract
Ralstonia solanacearum is a soil-borne pathogen that causes bacterial wilt in plants. The wild-type strain of R. solanacearum undergoes spontaneous phenotype conversion (PC), from a fluidal to non-fluidal colony morphology. PC mutants are non-pathogenic due to reduced virulence factors, and can control wilt diseases as biological control agents. The induction factors of PC in R. solanacearum are currently unclear. Here, we investigated the effect of iron treatment on bacterial growth of wild-type strain and PC mutant, and PC of the wild-type strain in liquid medium. Interestingly, PC was frequently induced in the single cultured wild-type strain by iron treatment; however, PC was not induced in the co-culture. In a co-culture of both strains, the PC mutant showed increased growth compared to the wild-type strain by iron treatment. Furthermore, we investigated the effects of iron treatment on the bacterial growth and PC of the wild-type strain under different culture conditions of medium type (MM broth, BG broth, and water medium), iron compounds, and pH. In BG broth, PC occurred frequently regardless of iron treatment. In MM broth, the optimal conditions for high frequency induction of PC by iron treatments were treatment of iron (III) EDTA, and under pH 7-8. Conversely, PC was not induced by iron treatment in water medium and in MM broth under pH 5 conditions. Common to the culture conditions wherein PC was not induced by iron treatment, the bacterial density of the wild-type strain was as low as 106 CFU mL-1 or less. Finally, we investigated the effects on bacterial growth and PC of the wild-type strain by the iron treatment and addition of culture filtrate after cultivation of the wild-type strain at high concentration. In medium containing only the culture filtrate, PC did not occur. However, in medium containing the culture filtrate and iron, PC occurred frequently. Our results thus suggest that high-density growth of the wild-type strain as well as the presence of iron are involved in inducing PC in R. solanacearum.
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Affiliation(s)
- Hiroki Nakahara
- Arid Land Research Center, Tottori University, Hamasaka 1390, Tottori 680-0001, Japan.
| | - Kento Mori
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, Higashi-ku, Kumamoto 862-8502, Japan
| | - Taro Mori
- Faculty of Education, Shiga University, Hiratsu 2-5-1, Otsu, Shiga 520-0862, Japan
| | - Naotaka Matsuzoe
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, Higashi-ku, Kumamoto 862-8502, Japan
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15
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Patel RR, Kandel PP, Traverso E, Hockett KL, Triplett LR. Pseudomonas syringae pv. phaseolicola Uses Distinct Modes of Stationary-Phase Persistence To Survive Bacteriocin and Streptomycin Treatments. mBio 2021; 12:e00161-21. [PMID: 33849974 PMCID: PMC8092213 DOI: 10.1128/mbio.00161-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/11/2021] [Indexed: 02/08/2023] Open
Abstract
Antimicrobial treatment of bacteria often results in a small population of surviving tolerant cells, or persisters, that may contribute to recurrent infection. Antibiotic persisters are metabolically dormant, but the basis of their persistence in the presence of membrane-disrupting biological compounds is less well understood. We previously found that the model plant pathogen Pseudomonas syringae pv. phaseolicola 1448A (Pph) exhibits persistence to tailocin, a membrane-disrupting biocontrol compound with potential for sustainable disease control. Here, we compared physiological traits associated with persistence to tailocin and to the antibiotic streptomycin and established that both treatments leave similar frequencies of persisters. Microscopic profiling of treated populations revealed that while tailocin rapidly permeabilizes most cells, streptomycin treatment results in a heterogeneous population in the redox and membrane permeability state. Intact cells were sorted into three fractions according to metabolic activity, as indicated by a redox-sensing reporter dye. Streptomycin persisters were cultured from the fraction associated with the lowest metabolic activity, but tailocin persisters were cultured from a fraction associated with an active metabolic signal. Cells from culturable fractions were able to infect host plants, while the nonculturable fractions were not. Tailocin and streptomycin were effective in eliminating all persisters when applied sequentially, in addition to eliminating cells in other viable states. This study identifies distinct metabolic states associated with antibiotic persistence, tailocin persistence, and loss of virulence and demonstrates that tailocin is highly effective in eliminating dormant cells.IMPORTANCE Populations of genetically identical bacteria encompass heterogeneous physiological states. The small fraction of bacteria that are dormant can help the population survive exposure to antibiotics and other stresses, potentially contributing to recurring infection cycles in animal or plant hosts. Membrane-disrupting biological control treatments are effective in killing dormant bacteria, but these treatments also leave persister-like survivors. The current work demonstrates that in Pph, persisters surviving treatment with membrane-disrupting tailocin proteins have an elevated redox state compared to that of dormant streptomycin persisters. Combination treatment was effective in killing both persister types. Culturable persisters corresponded closely with infectious cells in each treated population, whereas the high-redox and unculturable fractions were not infectious. In linking redox states to heterogeneous phenotypes of tailocin persistence, streptomycin persistence, and infection capability, this work will inform the search for mechanisms and markers for each phenotype.
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Affiliation(s)
- Ravikumar R Patel
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Prem P Kandel
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Eboni Traverso
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Kevin L Hockett
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, Pennsylvania, USA
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, Pennsylvania, USA
- Huck Institutes for the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Lindsay R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
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16
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Wang M, Chen H, Liu S, Xiao L. Removal of pathogen and antibiotic resistance genes from waste activated sludge by different pre-treatment approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:143014. [PMID: 33190880 DOI: 10.1016/j.scitotenv.2020.143014] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/12/2020] [Accepted: 10/07/2020] [Indexed: 05/13/2023]
Abstract
In wastewater treatment plants, most of the pathogens and antibiotic resistant genes (ARGs) transferred into and concentrated in waste activated sludge (WAS), which would cause severe public health risks. In this study, the capabilities of several WAS pre-treatment approaches to inactivate coliforms/E. coli and ARGs, as well as the subsequent regrowth of coliforms/E. coli and ARGs/intI1 in treated sludge were investigated. The results showed that electro-Fenton (EF), with continuous hydroxyl radical generation, could efficiently inactivate coliforms/E. coli in 60 min (about 4 log units), followed by methanol (MT), anode oxidization (AO), and acidification (AT). Kinetic analysis showed that the inactivation mainly occurred in the first 10 min. However, the efficiencies of all studied pre-treatment approaches on inactivating ARGs/intI1 (<2 log units) were lower than coliforms/E. coli, whilst EF still had the highest efficiency of ARGs/intI1 reduction. Mechanical ultrasound treatment (ULS) could not inactivate coliforms/E. coli in WAS, but it could efficiently reduce ARGs/intI1. High regrowth rates of coliforms/E. coli were observed in the treated WAS in 10 days, but the abundances of ARGs/intI1 continuously reduced during the after-treatment incubation. Our study showed that EF could efficiently disinfect potential pathogens, however, the reduction of ARGs/intI1 in WAS need further investigation.
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Affiliation(s)
- Min Wang
- State Key laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Huiping Chen
- State Key laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Shulei Liu
- State Key laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Lin Xiao
- State Key laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
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17
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Martins PMM, Wood TK, de Souza AA. Persister Cells Form in the Plant Pathogen Xanthomonas citri subsp. citri under Different Stress Conditions. Microorganisms 2021; 9:microorganisms9020384. [PMID: 33672822 PMCID: PMC7918609 DOI: 10.3390/microorganisms9020384] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/16/2022] Open
Abstract
Citrus canker disease, caused by the bacterium Xanthomonas citri subsp. citri is a constant threat to citrus-producing areas. Since it has no cure, agricultural practices to restrain its dissemination are essential to reduce the economic damage. Hence, increased knowledge of the basic aspects of X. citri biology could lead to more efficient management practices that can eliminate dormant bacteria in the field. The dormant cells, also referred to as persisters, are phenotypic variants with lowered metabolism, which in turn leads to tolerance to antimicrobials and undermines existing control approaches. We show here that X. citri forms persisters, identifying triggers for this phenotype, including antibiotics, high temperature, and metals (copper and zinc), which increase persistence rates by 10–100 times. The antioxidant N-acetylcysteine reduced copper and zinc-induced persisters, but not those induced by tetracycline, indicating that oxidative stress may be an important inducer of X. citri persistence. In addition, we found that metabolism-independent drugs like cisplatin and mitomycin C are able to eliminate X. citri persistent cells, as well as copper, at high concentrations. Specific amino acids like proline and isoleucine interfered with the physiological balance of the dormancy in X. citri, stimulating or preventing persister resuscitation. Taken together, we discover chemicals that can induce, wake, and kill X. citri persister cells; these results provide insights that should be considered for more efficient integrated control management in the field.
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Affiliation(s)
- Paula M. M. Martins
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA;
- Biotechnology Laboratory, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Rodovia Anhanguera Km 158, Cordeirópolis-SP 13490-000, Brazil
| | - Thomas K. Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA;
- Correspondence: (T.K.W.); (A.A.d.S.)
| | - Alessandra A. de Souza
- Biotechnology Laboratory, Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Rodovia Anhanguera Km 158, Cordeirópolis-SP 13490-000, Brazil
- Correspondence: (T.K.W.); (A.A.d.S.)
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18
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Maertens L, Matroule JY, Van Houdt R. Characteristics of the copper-induced viable-but-non-culturable state in bacteria. World J Microbiol Biotechnol 2021; 37:37. [PMID: 33544256 PMCID: PMC7864824 DOI: 10.1007/s11274-021-03006-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/17/2021] [Indexed: 02/06/2023]
Abstract
The antimicrobial applications of copper (Cu) are exploited in several industries, such as agriculture and healthcare settings. While Cu is capable of efficiently killing microorganisms, sub-lethal doses can induce a viable-but-non-culturable (VBNC) state in bacteria of many distinct clades. VBNC cells cannot be detected by standard culture-based detection methods, and can become a threat to plants and animals as they often retain virulent traits upon resuscitation. Here we discuss the putative mechanisms of the Cu-induced VBNC state. Common observations in Cu-induced VBNC cells include a cellular response to reactive oxygen species, the exhaustion of energy reserves, and a reconfiguration of the proteome. While showing partial overlap with other VBNC state-inducing stressors, these changes seem to be part of an adaptive response to Cu toxicity. Furthermore, we argue that Cu resistance mechanisms such as P-type ATPases and multicopper oxidases may ward off entry into the VBNC state to some extent. The spread of these mechanisms across multi-species populations could increase population-level resistance to Cu antimicrobials. As Cu resistance mechanisms are often co-selected with antibiotic resistance mechanisms, this threat is exacerbated.
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Affiliation(s)
- Laurens Maertens
- Microbiology Unit, Interdisciplinary Biosciences, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium.,Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, Namur, Belgium
| | - Jean-Yves Matroule
- Research Unit in Microorganisms Biology (URBM), Narilis Institute, University of Namur, Namur, Belgium
| | - Rob Van Houdt
- Microbiology Unit, Interdisciplinary Biosciences, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium.
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19
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Ho TH, Chuang CY, Zheng JL, Chen HH, Liang YS, Huang TP, Lin YH. Bacillus amyloliquefaciens Strain PMB05 Intensifies Plant Immune Responses to Confer Resistance Against Bacterial Wilt of Tomato. PHYTOPATHOLOGY 2020; 110:1877-1885. [PMID: 32692280 DOI: 10.1094/phyto-01-20-0026-r] [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: 06/11/2023]
Abstract
Tomato is an economic crop worldwide. Many limiting factors reduce the production of tomato, with bacterial wilt caused by Ralstonia solanacearum being the most destructive disease. Our previous study showed that the disease resistance to bacterial soft rot is enhanced by Bacillus amyloliquefaciens strain PMB05. This enhanced resistance is associated with the intensification of pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). To determine whether the PTI-intensifying Bacillus spp. strains are able to confer disease resistance to bacterial wilt, their effects on PTI signals triggered by PAMP from R. solanacearum and on the occurrence of bacterial wilt were assayed. Before assay, a gene that encodes harpin from R. solanacearum, PopW, was applied as a PAMP. Results revealed that the B. amyloliquefaciens strain PMB05 was the one strain among 9 Bacillus rhizobacterial strains which could significantly intensify the PopW-induced hypersensitive response (HR) on Arabidopsis leaves. Moreover, we observed that the signals of PopW-induced reactive oxygen species generation and callose deposition were increased, confirming that the PTI was intensified by PMB05. The intensification of the PopW-triggered HR by PMB05 in Arabidopsis was reduced upon treatment with inhibitors in PTI pathways. Furthermore, the application of Bacillus spp. strains on tomato plants showed that only the use of PMB05 resulted in significantly increased resistance to bacterial wilt. Moreover, the PTI signals were also intensified in the tomato leaves. Taken together, we demonstrated that PMB05 is a PTI-intensifying bacterium that confers resistance to tomato bacterial wilt. Screening of plant immunity intensifying rhizobacteria is a possible strategy to control tomato bacterial wilt.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Ting-Hsin Ho
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chiao-Yu Chuang
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Jing-Lin Zheng
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Hong-Hua Chen
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Yu-Shen Liang
- Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Tzu-Pi Huang
- Department of Plant Pathology, National Chung-Hsing University, Taichung, Taiwan
| | - Yi-Hsien Lin
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
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20
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Baró A, Badosa E, Montesinos L, Feliu L, Planas M, Montesinos E, Bonaterra A. Screening and identification of BP100 peptide conjugates active against Xylella fastidiosa using a viability-qPCR method. BMC Microbiol 2020; 20:229. [PMID: 32727358 PMCID: PMC7392676 DOI: 10.1186/s12866-020-01915-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Background Xylella fastidiosa is one of the most harmful bacterial plant pathogens worldwide, causing a variety of diseases, with huge economic impact to agriculture and environment. Although it has been extensively studied, there are no therapeutic solutions to suppress disease development in infected plants. In this context, antimicrobial peptides represent promising alternatives to traditional compounds due to their activity against a wide range of plant pathogens, their low cytotoxicity, their mode of action that make resistance more difficult and their availability for being expressed in plants. Results Peptide conjugates derived from the lead peptide BP100 and fragments of cecropin, magainin or melittin were selected and tested against the plant pathogenic bacteria X. fastidiosa. In order to screen the activity of these antimicrobials, and due to the fastidious nature of the pathogen, a methodology consisting of a contact test coupled with the viability-quantitative PCR (v-qPCR) method was developed. The nucleic acid-binding dye PEMAX was used to selectively quantify viable cells by v-qPCR. In addition, the primer set XF16S-3 amplifying a 279 bp fragment was selected as the most suitable for v-qPCR. The performance of the method was assessed by comparing v-qPCR viable cells estimation with conventional qPCR and plate counting. When cells were treated with peptide conjugates derived from BP100, the observed differences between methods suggested that, in addition to cell death due to the lytic effect of the peptides, there was an induction of the viable but non-culturable state in cells. Notably, a contact test coupled to v-qPCR allowed fast and accurate screening of antimicrobial peptides, and led to the identification of new peptide conjugates active against X. fastidiosa. Conclusions Antimicrobial peptides active against X. fastidiosa have been identified using an optimized methodology that quantifies viable cells without a cultivation stage, avoiding underestimation or false negative detection of the pathogen due to the viable but non-culturable state, and overestimation of the viable population observed using qPCR. These findings provide new alternative compounds for being tested in planta for the control of X. fastidiosa, and a methodology that enables the fast screening of a large amount of antimicrobials against this plant pathogenic bacterium.
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Affiliation(s)
- Aina Baró
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Esther Badosa
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Laura Montesinos
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Lidia Feliu
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Marta Planas
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Emilio Montesinos
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Anna Bonaterra
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain.
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21
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Im SM, Yu NH, Joen HW, Kim SO, Park HW, Park AR, Kim JC. Biological control of tomato bacterial wilt by oxydifficidin and difficidin-producing Bacillus methylotrophicus DR-08. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 163:130-137. [PMID: 31973849 DOI: 10.1016/j.pestbp.2019.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/25/2019] [Accepted: 11/06/2019] [Indexed: 06/10/2023]
Abstract
Bacillus methylotrophicus DR-08 exhibited strong antibacterial activity against Ralstonia solanacearum, a causal agent of tomato bacterial wilt. This study aimed to identify the antibacterial metabolites and evaluate the efficacy of the strain as a biocontrol agent for tomato bacterial wilt. A butanol extract of the DR-08 broth culture completely inhibited the growth of 14 phytopathogenic bacteria with minimum inhibitory concentration (MIC) values of 1.95-500 μg/mL. R. solanacearum was highly sensitive to the DR-08 extract, with an MIC value of 12.62 μg/mL. Two antibacterial metabolites were isolated and identified as difficidin and oxydifficidin derivatives through bioassay-guided fractionation and instrumental analyses. Both metabolite derivatives inhibited the growth of most of the phytopathogenic bacteria tested and the oxydifficidin derivatives generally presented a stronger antibacterial activity than the difficidin derivatives. A 30% suspension concentrate of DR-08, at a 500-fold dilution, effectively suppressed the development of tomato bacterial wilt in pot and field experiments. It also effectively reduced the development of bacterial leaf spot symptoms on peach and red pepper. The results of this study suggests that B. methylotrophicus DR-08 can be utilized as a biocontrol agent for various bacterial plant diseases including tomato bacterial wilt.
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Affiliation(s)
- Seong Mi Im
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Nan Hee Yu
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Hee Won Joen
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Soon Ok Kim
- Biological and Genetic Resources Assessment Division, National Institute of Biological Resources, 42 Hwangyeong-ro, Seo-gu, Incheon 22689, Republic of Korea
| | - Hae Woong Park
- R&D Division, World Institute of Kimchi, 86 Kimchi-ro, Nam-gu, Gwangju 61755, Republic of Korea
| | - Ae Ran Park
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
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22
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Elsayed TR, Jacquiod S, Nour EH, Sørensen SJ, Smalla K. Biocontrol of Bacterial Wilt Disease Through Complex Interaction Between Tomato Plant, Antagonists, the Indigenous Rhizosphere Microbiota, and Ralstonia solanacearum. Front Microbiol 2020; 10:2835. [PMID: 31998244 PMCID: PMC6967407 DOI: 10.3389/fmicb.2019.02835] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/22/2019] [Indexed: 11/25/2022] Open
Abstract
Ralstonia solanacearum (biovar2, race3) is the causal agent of bacterial wilt and this quarantine phytopathogen is responsible for massive losses in several commercially important crops. Biological control of this pathogen might become a suitable plant protection measure in areas where R. solanacearum is endemic. Two bacterial strains, Bacillus velezensis (B63) and Pseudomonas fluorescens (P142) with in vitro antagonistic activity toward R. solanacearum (B3B) were tested for rhizosphere competence, efficient biological control of wilt symptoms on greenhouse-grown tomato, and effects on the indigenous rhizosphere prokaryotic communities. The population densities of B3B and the antagonists were estimated in rhizosphere community DNA by selective plating, real-time quantitative PCR, and R. solanacearum-specific fliC PCR-Southern blot hybridization. Moreover, we investigated how the pathogen and/or the antagonists altered the composition of the tomato rhizosphere prokaryotic community by 16S rRNA gene amplicon sequencing. B. velezensis (B63) and P. fluorescens (P142)-inoculated plants showed drastically reduced wilt disease symptoms, accompanied by significantly lower abundance of the B3B population compared to the non-inoculated pathogen control. Pronounced shifts in prokaryotic community compositions were observed in response to the inoculation of B63 or P142 in the presence or absence of the pathogen B3B and numerous dynamic taxa were identified. Confocal laser scanning microscopy (CLSM) visualization of the gfp-tagged antagonist P142 revealed heterogeneous colonization patterns and P142 was detected in lateral roots, root hairs, epidermal cells, and within xylem vessels. Although competitive niche exclusion cannot be excluded, it is more likely that the inoculation of P142 or B63 and the corresponding microbiome shifts primed the plant defense against the pathogen B3B. Both inoculants are promising biological agents for efficient control of R. solanacearum under field conditions.
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Affiliation(s)
- Tarek R Elsayed
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Braunschweig, Germany.,Department of Microbiology, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Samuel Jacquiod
- Marine Microbiological Section, Department of Biology, Faculty of Natural and Life Sciences, University of Copenhagen, Copenhagen, Denmark.,Agroécologie, AgroSup Dijon, INRAE, Université Bourgogne, Université Bourgogne Franche-Comté, Dijon, France
| | - Eman H Nour
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Braunschweig, Germany
| | - Søren J Sørensen
- Marine Microbiological Section, Department of Biology, Faculty of Natural and Life Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kornelia Smalla
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Braunschweig, Germany
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23
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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24
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Characterization and complete genome sequence analysis of phage GP4, a novel lytic Bcep22-like podovirus. Arch Virol 2019; 164:2339-2343. [DOI: 10.1007/s00705-019-04309-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/06/2019] [Indexed: 11/30/2022]
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25
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Kan Y, Jiang N, Xu X, Lyu Q, Gopalakrishnan V, Walcott R, Burdman S, Li J, Luo L. Induction and Resuscitation of the Viable but Non-culturable (VBNC) State in Acidovorax citrulli, the Causal Agent of Bacterial Fruit Blotch of Cucurbitaceous Crops. Front Microbiol 2019; 10:1081. [PMID: 31156591 PMCID: PMC6529555 DOI: 10.3389/fmicb.2019.01081] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/29/2019] [Indexed: 01/14/2023] Open
Abstract
Acidovorax citrulli is a gram-negative bacterium that infects a wide range of cucurbits causing bacterial fruit blotch (BFB) disease. Copper-based compounds are the most widely-used chemicals for managing BFB and other bacterial diseases in the field. Many bacteria can enter a viable but non-culturable (VBNC) state in response to stress, including exposure to copper, and recover the culturability when favorable conditions return. The present study demonstrates that A. citrulli strain AAC00-1 is able to enter into the VBNC state by treatment with different concentrations of copper sulfate. It took 3 h, 5 and 15 days for all viable cells to lose culturability upon exposure to copper sulfate concentrations of 50, 10, and 5 μM, respectively. The VBNC A. citrulli cells regained culturability when the Cu2+ ions were removed by chelation with EDTA or by transfer of cells to LB broth, a cell-free supernatant from a suspension of AAC00-1, oligotrophic media amended with casein hydrolysate or watermelon seedling juice. We also found that the VBNC cells induced by Cu2+ were unable to colonize or infect watermelon seedlings directly, but the resuscitated cells recovered full virulence equivalent to untreated bacterial cells in the log phase. To the best of our knowledge, this is the first report on the VBNC state in A. citrulli and the factors that facilitate resuscitation and restoration of pathogenicity.
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Affiliation(s)
- Yumin Kan
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Na Jiang
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Xin Xu
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Qingyang Lyu
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Vinoj Gopalakrishnan
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ronald Walcott
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Saul Burdman
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Jianqiang Li
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Laixin Luo
- Department of Plant Pathology, China Agricultural University, Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
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26
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Murugan K, Vasudevan N. Intracellular toxicity exerted by PCBs and role of VBNC bacterial strains in biodegradation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 157:40-60. [PMID: 29605643 DOI: 10.1016/j.ecoenv.2018.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/22/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Polychlorinated biphenyls (PCBs) are xenobiotic compounds that persists in the environment for long-term, though its productivity is banned. Abatement of the pollutants have become laborious due to it's recalcitrant nature in the environment leading to toxic effects in humans and other living beings. Biphenyl degrading bacteria co-metabolically degrade low chlorinated PCBs using the active metabolic pathway. bph operon possess different genetic arrangements in gram positive and gram negative bacteria. The binding ability of the genes and the active sites were determined by PCB docking studies. The active site of bphA gene with conserved amino acid residues determines the substrate specificity and biodegradability. Accumulation of toxic intermediates alters cellular behaviour, biomass production and downturn the metabolic activity. Several bacteria in the environment attain unculturable state which is viable and metabolically active but not cultivable (VBNC). Resuscitation-promoting factor (Rpf) and Rpf homologous protein retrieve the culturability of the so far uncultured bacteria. Recovery of this adaptive mechanism against various physical and chemical stressors make a headway in understanding the functionality of both environmental and medically important unculturable bacteria. Thus, this paper review about the general aspects of PCBs, cellular toxicity exerted by PCBs, role of unculturable bacterial strains in biodegradation, genes involved and degradation pathways. It is suggested to extrapolate the research findings on extracellular organic matters produced in culture supernatant of VBNC thus transforming VBNC to culturable state.
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Affiliation(s)
- Karuvelan Murugan
- Centre for Environmental Studies, Anna University, CEG Campus, Chennai, Tamil Nadu, India.
| | - Namasivayam Vasudevan
- Centre for Environmental Studies, Anna University, CEG Campus, Chennai, Tamil Nadu, India.
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27
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Liu J, Deng Y, Li L, Li B, Li Y, Zhou S, Shirtliff ME, Xu Z, Peters BM. Discovery and control of culturable and viable but non-culturable cells of a distinctive Lactobacillus harbinensis strain from spoiled beer. Sci Rep 2018; 8:11446. [PMID: 30061572 PMCID: PMC6065415 DOI: 10.1038/s41598-018-28949-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/02/2018] [Indexed: 11/09/2022] Open
Abstract
Occasional beer spoilage incidents caused by false-negative isolation of lactic acid bacteria (LAB) in the viable but non-culturable (VBNC) state, result in significant profit loss and pose a major concern in the brewing industry. In this study, both culturable and VBNC cells of an individual Lactobacillus harbinensis strain BM-LH14723 were identified in one spoiled beer sample by genome sequencing, with the induction and resuscitation of VBNC state for this strain further investigated. Formation of the VBNC state was triggered by low-temperature storage in beer (175 ± 1.4 days) and beer subculturing (25 ± 0.8 subcultures), respectively, and identified by both traditional staining method and PMA-PCR. Resuscitated cells from the VBNC state were obtained by addition of catalase rather than temperature upshift, changing medium concentration, and adding other chemicals, and both VBNC and resuscitated cells retained similar beer-spoilage capability as exponentially growing cells. In addition to the first identification of both culturable and VBNC cells of an individual L. harbinensis strain from spoiled beer, this study also for the first time reported the VBNC induction and resuscitation, as well as verification of beer-spoilage capability of VBNC and resuscitated cells for the L. harbinensis strain. Genes in association with VBNC state were also identified by the first genome sequencing of beer spoilage L. harbinensis. The results derived from this study suggested the contamination and spoilage of beer products by VBNC and resuscitated L. harbinensis strain BM-LH14723.
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Affiliation(s)
- Junyan Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China.,Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Yang Deng
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, P.R. China
| | - Lin Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China. .,School of Chemical Engineering and Energy Technology, Dongguan University of Technology, Dongguan, 523808, China. .,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, 510640, China.
| | - Bing Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China.,Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, 510640, China
| | - Yanyan Li
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Shishui Zhou
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, 510006, China
| | - Mark E Shirtliff
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore MD, MA, 21201, USA
| | - Zhenbo Xu
- School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China. .,College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, P.R. China. .,Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore MD, MA, 21201, USA.
| | - Brian M Peters
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
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28
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Martins PMM, Merfa MV, Takita MA, De Souza AA. Persistence in Phytopathogenic Bacteria: Do We Know Enough? Front Microbiol 2018; 9:1099. [PMID: 29887856 PMCID: PMC5981161 DOI: 10.3389/fmicb.2018.01099] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/08/2018] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria affect a wide range of crops worldwide and have a negative impact in agriculture due to their associated economic losses and environmental impacts. Together with other biotic and abiotic stress factors, they pose a threat to global food production. Therefore, understanding bacterial survival strategies is an essential step toward the development of new strategies to control plant diseases. One mechanism used by bacteria to survive under stress conditions is the formation of persister cells. Persisters are a small fraction of phenotypic variants within an isogenic population that exhibits multidrug tolerance without undergoing genetic changes. They are dormant cells that survive treatment with antimicrobials by inactivating the metabolic functions that are disrupted by these compounds. They are thus responsible for the recalcitrance of many human diseases, and in the same way, they are thought to contribute to the survival of bacterial phytopathogens under a range of stresses they face in the environment. It is believed that persister cells of bacterial phytopathogens may lead to the reoccurrence of disease by recovering growth and recolonizing the host plant after the end of stress. However, compared to human pathogens, little is known about persister cells in phytopathogens, especially about their genetic regulation. In this review, we describe the overall knowledge on persister cells and their regulation in bacterial phytopathogens, focusing on their ability to survive stress conditions, to recover from dormancy and to maintain virulence.
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Affiliation(s)
- Paula M. M. Martins
- Laboratório de Biotecnologia, Centro de Citricultura, Instituto Agronômico de Campinas, Cordeiropolis, Brazil
| | - Marcus V. Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Marco A. Takita
- Laboratório de Biotecnologia, Centro de Citricultura, Instituto Agronômico de Campinas, Cordeiropolis, Brazil
| | - Alessandra A. De Souza
- Laboratório de Biotecnologia, Centro de Citricultura, Instituto Agronômico de Campinas, Cordeiropolis, Brazil
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29
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Deberdt P, Davezies I, Coranson-Beaudu R, Jestin A. Efficacy of Leaf Oil from Pimenta racemosa var. racemosa in Controlling Bacterial Wilt of Tomato. PLANT DISEASE 2018; 102:124-131. [PMID: 30673454 DOI: 10.1094/pdis-04-17-0593-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacterial wilt, caused by Ralstonia solanacearum, is a major plant disease throughout the Caribbean. The ability of the essential oil from Pimenta racemosa var. racemosa to control bacterial wilt of tomato (R. solanacearum, phylotype IIB/4NPB) was investigated. Lemongrass (chemotype 1)-, aniseed (chemotype 2)-, and clove (chemotype 3)-scented chemotypes of P. racemosa var. racemosa essential oil were tested. Six concentrations of emulsified essential oil (from 0.01 to 0.14% [v/v]) were evaluated by in vitro culture amendment assays and by in vivo experiments in greenhouse. Chemotype 3 displayed remarkable in vitro antibacterial activity against R. solanacearum, because the minimum inhibitory concentration was only 0.03%, compared with 0.14% for chemotypes 1 and 2. In greenhouse experiments, no incidence of bacterial wilt was observed in tomato plants grown in soil treated with chemotype 3 of P. racemosa var. racemosa at a concentration of 0.14%. In the untreated control soil, 62% of plants displayed symptoms of bacterial wilt. Treatment with chemotype 3 significantly increased the growth of tomato plants compared with untreated controls. These results suggest that chemotype 3 of P. racemosa var. racemosa essential oil is a good candidate for further development as a soil biofumigant for the control of tomato bacterial wilt.
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Affiliation(s)
- Péninna Deberdt
- CIRAD, UPR HORTSYS, Campus Agro-Environnemental Caraïbe, F-97285, Le Lamentin, Martinique, France
| | - Isabelle Davezies
- CIRAD, UPR HORTSYS, Campus Agro-Environnemental Caraïbe, F-97285, Le Lamentin, Martinique, France
| | - Régine Coranson-Beaudu
- CIRAD, UPR HORTSYS, Campus Agro-Environnemental Caraïbe, F-97285, Le Lamentin, Martinique, France
| | - Alexandra Jestin
- CIRAD, UPR HORTSYS, Campus Agro-Environnemental Caraïbe, F-97285, Le Lamentin, Martinique, France
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30
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Zhong H, Zhong Y, Deng Q, Zhou Z, Guan X, Yan M, Hu T, Luo M. Virulence of thermolable haemolysi tlh, gastroenteritis related pathogenicity tdh and trh of the pathogens Vibrio Parahemolyticus in Viable but Non-Culturable (VBNC) state. Microb Pathog 2017; 111:352-356. [DOI: 10.1016/j.micpath.2017.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
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31
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Shidore T, Triplett LR. Toxin-Antitoxin Systems: Implications for Plant Disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:161-179. [PMID: 28525308 DOI: 10.1146/annurev-phyto-080516-035559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toxin-antitoxin (TA) systems are gene modules that are ubiquitous in free-living prokaryotes. Diverse in structure, cellular function, and fitness roles, TA systems are defined by the presence of a toxin gene that suppresses bacterial growth and a toxin-neutralizing antitoxin gene, usually encoded in a single operon. Originally viewed as DNA maintenance modules, TA systems are now thought to function in many roles, including bacterial stress tolerance, virulence, phage defense, and biofilm formation. However, very few studies have investigated the significance of TA systems in the context of plant-microbe interactions. This review discusses the potential impact and application of TA systems in plant-associated bacteria, guided by insights gained from animal-pathogenic model systems.
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Affiliation(s)
- T Shidore
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
| | - L R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
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32
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Álvarez B, Biosca EG. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture. FRONTIERS IN PLANT SCIENCE 2017; 8:1218. [PMID: 28769942 PMCID: PMC5509943 DOI: 10.3389/fpls.2017.01218] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/28/2017] [Indexed: 05/03/2023]
Abstract
Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis, not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta. Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field.
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Affiliation(s)
- Belén Álvarez
- Departamento de Investigación Aplicada y Extensión Agraria, Instituto Madrileño de Investigación y Desarrollo Rural, Agrario y AlimentarioMadrid, Spain
| | - Elena G. Biosca
- Departamento de Microbiología y Ecología, Universitat de ValènciaValencia, Spain
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33
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Coutinho TA, Wingfield MJ. Ralstonia solanacearum and R. pseudosolanacearum on Eucalyptus: Opportunists or Primary Pathogens? FRONTIERS IN PLANT SCIENCE 2017; 8:761. [PMID: 28553301 PMCID: PMC5425484 DOI: 10.3389/fpls.2017.00761] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Ralstonia solanacearum and R. pseudosolanacearum are well known primary pathogens of herbaceous crops. Reports of wilt caused by these pathogens in tree species are limited other than on Eucalyptus species. Despite the widespread occurrence of so-called bacterial wilt on eucalypts in tropical and sub-tropical parts of Africa, Asia, and the Americas, there remain many contradictions relating to the disease. Our field observations over many years in most regions where the disease occurs on Eucalyptus show that it is always associated with trees that have been subjected to severe stress. The disease is typically diagnosed by immersing cut stems in water and observing bacterial streaming, but the identity of the bacteria within this suspension is seldom considered. To add to the confusion, pathogenicity tests on susceptible species or clones are rarely successful. When they do work, they are on small plants in greenhouse trials. It has become all to easy to attribute Eucalyptus death exclusively to Ralstonia infection. Our data strongly suggest that Ralstonia species and probably other bacteria are latent colonists commonly occurring in healthy and particularly clonally propagated eucalypts. The onset of stress factors provide the bacteria with an opportunity to develop. We believe that the resulting stress weakens the defense systems of the trees allowing Ralstonia and bacterial endophytes to proliferate. Overall our research suggests that R. solanacearum and R. pseudosolanacearum are not primary pathogens of Eucalyptus. Short of clear evidence that they are primary pathogens of Eucalyptus it is inappropriate to attribute this disease solely to infection by Ralstonia species.
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Affiliation(s)
- Teresa A. Coutinho
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of PretoriaPretoria, South Africa
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Erill I, Puigvert M, Legrand L, Guarischi-Sousa R, Vandecasteele C, Setubal JC, Genin S, Guidot A, Valls M. Comparative Analysis of Ralstonia solanacearum Methylomes. FRONTIERS IN PLANT SCIENCE 2017; 8:504. [PMID: 28450872 PMCID: PMC5390034 DOI: 10.3389/fpls.2017.00504] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/22/2017] [Indexed: 05/24/2023]
Abstract
Ralstonia solanacearum is an important soil-borne plant pathogen with broad geographical distribution and the ability to cause wilt disease in many agriculturally important crops. Genome sequencing of multiple R. solanacearum strains has identified both unique and shared genetic traits influencing their evolution and ability to colonize plant hosts. Previous research has shown that DNA methylation can drive speciation and modulate virulence in bacteria, but the impact of epigenetic modifications on the diversification and pathogenesis of R. solanacearum is unknown. Sequencing of R. solanacearum strains GMI1000 and UY031 using Single Molecule Real-Time technology allowed us to perform a comparative analysis of R. solanacearum methylomes. Our analysis identified a novel methylation motif associated with a DNA methylase that is conserved in all complete Ralstonia spp. genomes and across the Burkholderiaceae, as well as a methylation motif associated to a phage-borne methylase unique to R. solanacearum UY031. Comparative analysis of the conserved methylation motif revealed that it is most prevalent in gene promoter regions, where it displays a high degree of conservation detectable through phylogenetic footprinting. Analysis of hyper- and hypo-methylated loci identified several genes involved in global and virulence regulatory functions whose expression may be modulated by DNA methylation. Analysis of genome-wide modification patterns identified a significant correlation between DNA modification and transposase genes in R. solanacearum UY031, driven by the presence of a high copy number of ISrso3 insertion sequences in this genome and pointing to a novel mechanism for regulation of transposition. These results set a firm foundation for experimental investigations into the role of DNA methylation in R. solanacearum evolution and its adaptation to different plants.
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Affiliation(s)
- Ivan Erill
- Department of Biological Sciences, University of Maryland Baltimore CountyBaltimore, MD, USA
- Center for Research in Agricultural Genomics, CSIC- IRTA- UAB -UBBarcelona, Spain
| | - Marina Puigvert
- Center for Research in Agricultural Genomics, CSIC- IRTA- UAB -UBBarcelona, Spain
- Department of Genetics, Universitat de BarcelonaBarcelona, Spain
| | - Ludovic Legrand
- Laboratoire des Interactions Plantes Micro-organismes, INRA, Centre National de la Recherche Scientifique, Université de ToulouseCastanet-Tolosan, France
| | - Rodrigo Guarischi-Sousa
- Departamento de Bioquímica, Instituto de Química, Universidade de São PauloSão Paulo, Brazil
| | | | - João C. Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São PauloSão Paulo, Brazil
| | - Stephane Genin
- Laboratoire des Interactions Plantes Micro-organismes, INRA, Centre National de la Recherche Scientifique, Université de ToulouseCastanet-Tolosan, France
| | - Alice Guidot
- Laboratoire des Interactions Plantes Micro-organismes, INRA, Centre National de la Recherche Scientifique, Université de ToulouseCastanet-Tolosan, France
| | - Marc Valls
- Center for Research in Agricultural Genomics, CSIC- IRTA- UAB -UBBarcelona, Spain
- Department of Genetics, Universitat de BarcelonaBarcelona, Spain
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New Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Scheme for Fine-Scale Monitoring and Microevolution-Related Study of Ralstonia pseudosolanacearum Phylotype I Populations. Appl Environ Microbiol 2017; 83:AEM.03095-16. [PMID: 28003195 DOI: 10.1128/aem.03095-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 12/13/2016] [Indexed: 12/31/2022] Open
Abstract
Bacterial wilt caused by the Ralstonia solanacearum species complex (RSSC) is considered one of the most harmful plant diseases in the world. Special attention should be paid to R. pseudosolanacearum phylotype I due to its large host range, its worldwide distribution, and its high evolutionary potential. So far, the molecular epidemiology and population genetics of this bacterium are poorly understood. Until now, the genetic structure of the RSSC has been analyzed on the worldwide and regional scales. Emerging questions regarding evolutionary forces in RSSC adaptation to hosts now require genetic markers that are able to monitor RSSC field populations. In this study, we aimed to evaluate the multilocus variable-number tandem-repeat analysis (MLVA) approach for its ability to discriminate genetically close phylotype I strains and for population genetics studies. We developed a new MLVA scheme (MLVA-7) allowing us to genotype 580 R. pseudosolanacearum phylotype I strains extracted from susceptible and resistant hosts and from different habitats (stem, soil, and rhizosphere). Based on specificity, polymorphism, and the amplification success rate, we selected seven fast-evolving variable-number tandem-repeat (VNTR) markers. The newly developed MLVA-7 scheme showed higher discriminatory power than the previously published MLVA-13 scheme when applied to collections sampled from the same location on different dates and to collections from different locations on very small scales. Our study provides a valuable tool for fine-scale monitoring and microevolution-related study of R. pseudosolanacearum phylotype I populations.IMPORTANCE Understanding the evolutionary dynamics of adaptation of plant pathogens to new hosts or ecological niches has become a key point for the development of innovative disease management strategies, including durable resistance. Whereas the molecular mechanisms underlying virulence or pathogenicity changes have been studied thoroughly, the population genetics of plant pathogen adaptation remains an open, unexplored field, especially for plant-pathogenic bacteria. MLVA has become increasingly popular for epidemiosurveillance and molecular epidemiology studies of plant pathogens. However, this method has been used mostly for genotyping and identification on a regional or global scale. In this study, we developed a new MLVA scheme, targeting phylotype I of the soilborne Ralstonia solanacearum species complex (RSSC), specifically to address the bacterial population genetics on the field scale. Such a MLVA scheme, based on fast-evolving loci, may be a tool of choice for field experimental evolution and spatial genetics studies.
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Fida TT, Moreno-Forero SK, Breugelmans P, Heipieper HJ, Röling WFM, Springael D. Physiological and Transcriptome Response of the Polycyclic Aromatic Hydrocarbon Degrading Novosphingobium sp. LH128 after Inoculation in Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1570-1579. [PMID: 28040887 DOI: 10.1021/acs.est.6b03822] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Soil bioaugmentation involves the inoculation of pollutant-degrading bacteria to accelerate pollutant degradation. Often the inoculum shows a dramatic decrease in Colony Forming Units (CFU) upon soil inoculation but this behavior is not well-understood. In this study, the physiology and transcriptomic response of a GFP tagged variant of Novosphingobium sp. LH128 was examined after inoculation into phenanthrene spiked soil. Four hours after inoculation, strain LH128-GFP showed about 99% reduction in CFU while microscopic counts of GFP-expressing cells were identical to the expected initial cell density, indicating that the reduction in CFU number is explained by cells entering into a Viable But Non-Culturable (VBNC)-like state and not by cell death. Transcriptome analysis showed a remarkably higher expression of phenanthrene degradation genes 4 h after inoculation, compared to the inoculum suspension concomitant with an increased expression of genes involved in stress response. This indicates that the cells were active in phenanthrene degradation while experiencing stress. Between 4 h and 10 days, CFU numbers increased to numbers comparable to the inoculated cell density. Our results suggest that strain LH128-GFP enters a VBNC-like state upon inoculation into soil but is metabolically active and that VBNC cells should be taken into account in evaluating bioaugmentation approaches.
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Affiliation(s)
- Tekle Tafese Fida
- Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Silvia K Moreno-Forero
- Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore Quartier Unil-Sorge , 1015 Lausanne, Switzerland
| | - Philip Breugelmans
- Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Hermann J Heipieper
- Department Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - Wilfred F M Röling
- Molecular Cell Physiology, FALW, VU University Amsterdam , De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Dirk Springael
- Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
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Yan M, Xu L, Jiang H, Zhou Z, Zhou S, Zhang L. PMA-LAMP for rapid detection of Escherichia coli and shiga toxins from viable but non-culturable state. Microb Pathog 2017; 105:245-250. [PMID: 28167125 DOI: 10.1016/j.micpath.2017.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 01/26/2017] [Accepted: 02/01/2017] [Indexed: 12/11/2022]
Abstract
In exposure to outer pressure, microorganisms are capable of entry into the Viable But Non-Culturable (VBNC) state, and thus survive under various elimination processing. The survival microorganisms may yield negative results on culturing, and cause false negative for this golden standard methodology. In this study, a novel PMA-LAMP assay on the detection of Enterohemorrhage E. coli and shiga toxins has been developed and evaluated, with further application on a number of food borne E. coli strains. LAMP primers were designed on the target of rfbe for Enterohemorrhage E. coli and stx1with stx2 for shiga toxins. Via specific penetration through the damaged cell membrane of dead cells and intercalating into DNA, PMA could prevent DNA amplification of dead bacteria from LAMP, which enabled the differentiation of bacteria between VBNC state and dead state. The established PMA-LAMP showed significant advantage in rapidity, sensitivity and specificity, compared with regular PCR assay. The applicability had also been verified, demonstrating the PMA-LAMP was capable of detection on Enterohemorrhage E. coli and shiga toxins.
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Affiliation(s)
- Muxia Yan
- Department of Haematology, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou 510623, PR China.
| | - Ling Xu
- Department of Haematology, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou 510623, PR China.
| | - Hua Jiang
- Department of Haematology, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou 510623, PR China.
| | - Zhenwen Zhou
- Clinical Microbiogy, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou 510180, PR China.
| | - Shishui Zhou
- School of Bioscience and Bioengineering, South China University of Technology, 382 Zhonghuan Road East, Guangzhou 510006, PR China.
| | - Li Zhang
- Department of Haematology, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou 510623, PR China.
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Aloyce A, Ndakidemi PA, Mbega ER. Identification and Management Challenges Associated with <I>Ralstonia solanacearum </I> (Smith), Causal Agent of Bacterial Wilt Disease of Tomato in Sub-Saharan Africa. Pak J Biol Sci 2017; 20:530-542. [PMID: 30187736 DOI: 10.3923/pjbs.2017.530.542] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tomato is the world's most consumed vegetable crop after potato and it is source of vitamins, minerals, fiber, lycopene, β-carotene and income. Despite its significant importance tomato can heavily be attacked by different pathogens including Ralstonia solanacearum that incites bacteria wilt disease. The disease is very devastating causing a considerable yield loss worldwide. The pathogen can survive in plant debris, infected plants and host weeds and spread from one field to another by irrigation or flood water, soil, farm equipment and workers and weeds which usually grow along waterways and it is difficult to manage due to complication in biology, nature of infestation and wide host range. In areas like the Sub-Saharan Africa where there exists a wide diversity of plant species, the pathogen becomes even more difficult to manage. It is on this basis that this review article, clearly discusses challenges for bacterial wilt disease identification and management in tomato farming systems with respect to the diagnosis methods used, pathogen genetic diversity and host range and pathogen survival mechanisms under different environment. The information will empower the responsible personnel involved in tomato production chain to have clear information about the pathogen and management options available against the disease in Sub-Saharan Africa.
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NAKAHARA H, MORI T, MATSUSAKI H, MATSUZOE N. Growth Inhibition of the Ralstonia solanacearum Wild-type Strain in a Culture Filtrate of Phenotypic Conversion Mutant Strain. ACTA ACUST UNITED AC 2016. [DOI: 10.2525/ecb.54.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hiroki NAKAHARA
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Taro MORI
- Faculty of Education, Shiga University
| | - Hiromi MATSUSAKI
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
| | - Naotaka MATSUZOE
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto
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Kong HG, Bae JY, Lee HJ, Joo HJ, Jung EJ, Chung E, Lee SW. Induction of the viable but nonculturable state of Ralstonia solanacearum by low temperature in the soil microcosm and its resuscitation by catalase. PLoS One 2014; 9:e109792. [PMID: 25296177 PMCID: PMC4190316 DOI: 10.1371/journal.pone.0109792] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/09/2014] [Indexed: 11/20/2022] Open
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt on a wide variety of plants, and enters a viable but nonculturable (VBNC) state under stress conditions in soil and water. Here, we adopted an artificial soil microcosm (ASM) to investigate the VBNC state of R. solanacearum induced by low temperature. The culturability of R. solanacearum strains SL341 and GMI1000 rapidly decreased at 4°C in modified ASM (mASM), while it was stably maintained at 25°C in mASM. We hypothesized that bacterial cells at 4°C in mASM are viable but nonculturable. Total protein profiles of SL341 cells at 4°C in mASM did not differ from those of SL341 culturable cells at 25°C in mASM. Moreover, the VBNC cells maintained in the mASM retained respiration activity. Catalase treatment effectively restored the culturability of nonculturable cells in mASM, while temperature increase or other treatments used for resuscitation of other bacteria were not effective. The resuscitated R. solanacearum from VBNC state displayed normal level of bacterial virulence on tomato plants compared with its original culturable bacteria. Expression of omp, oxyR, rpoS, dps, and the 16S rRNA gene quantified by RT-qPCR did not differ significantly between the culturable and VBNC states of R. solanacearum. Our results suggested that the VBNC bacterial cells in mASM induced by low temperature exist in a physiologically unique state.
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Affiliation(s)
- Hyun Gi Kong
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Ju Young Bae
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Hyoung Ju Lee
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Hae Jin Joo
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Eun Joo Jung
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Eunsook Chung
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
| | - Seon-Woo Lee
- Department of Applied Bioscience, Dong-A University, Busan, Republic of Korea
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Li L, Mendis N, Trigui H, Oliver JD, Faucher SP. The importance of the viable but non-culturable state in human bacterial pathogens. Front Microbiol 2014; 5:258. [PMID: 24917854 PMCID: PMC4040921 DOI: 10.3389/fmicb.2014.00258] [Citation(s) in RCA: 532] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/12/2014] [Indexed: 12/12/2022] Open
Abstract
Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed.
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Affiliation(s)
- Laam Li
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - Hana Trigui
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - James D Oliver
- Department of Biology, University of North Carolina at Charlotte Charlotte, NC, USA
| | - Sebastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
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Gorshkov V, Daminova A, Ageeva M, Petrova O, Gogoleva N, Tarasova N, Gogolev Y. Dissociation of a population of Pectobacterium atrosepticum SCRI1043 in tobacco plants: formation of bacterial emboli and dormant cells. PROTOPLASMA 2014; 251:499-510. [PMID: 23990131 DOI: 10.1007/s00709-013-0546-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/20/2013] [Indexed: 06/02/2023]
Abstract
The population dynamics of Pectobacterium atrosepticum SCRI1043 (Pba) within tobacco plants was monitored from the time of inoculation until after long-term preservation of microorganisms in the remnants of dead plants. We found and characterised peculiar structures that totally occlude xylem vessels, which we have named bacterial emboli. Viable but non-culturable (VBN) Pba cells were identified in the remnants of dead plants, and the conditions for resuscitation of these VBN cells were established. Our investigation shows that dissociation of the integrated bacterial population during plant colonisation forms distinct subpopulations and cell morphotypes, which are likely to perform specific functions that ensure successful completion of the life cycle within the plant.
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Affiliation(s)
- Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, Kazan Research Center, Russian Academy of Sciences, Lobachevsky Street 2/31, 420111, Kazan, Russia,
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Navarrete F, De La Fuente L. Response of Xylella fastidiosa to zinc: decreased culturability, increased exopolysaccharide production, and formation of resilient biofilms under flow conditions. Appl Environ Microbiol 2014; 80:1097-107. [PMID: 24271184 PMCID: PMC3911211 DOI: 10.1128/aem.02998-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/20/2013] [Indexed: 12/30/2022] Open
Abstract
The bacterial plant pathogen Xylella fastidiosa produces biofilm that accumulates in the host xylem vessels, affecting disease development in various crops and bacterial acquisition by insect vectors. Biofilms are sensitive to the chemical composition of the environment, and mineral elements being transported in the xylem are of special interest for this pathosystem. Here, X. fastidiosa liquid cultures were supplemented with zinc and compared with nonamended cultures to determine the effects of Zn on growth, biofilm, and exopolysaccharide (EPS) production under batch and flow culture conditions. The results show that Zn reduces growth and biofilm production under both conditions. However, in microfluidic chambers under liquid flow and with constant bacterial supplementation (closer to conditions inside the host), a dramatic increase in biofilm aggregates was seen in the Zn-amended medium. Biofilms formed under these conditions were strongly attached to surfaces and were not removed by medium flow. This phenomenon was correlated with increased EPS production in stationary-phase cells grown under high Zn concentrations. Zn did not cause greater adhesion to surfaces by individual cells. Additionally, viability analyses suggest that X. fastidiosa may be able to enter the viable but nonculturable state in vitro, and Zn can hasten the onset of this state. Together, these findings suggest that Zn can act as a stress factor with pleiotropic effects on X. fastidiosa and indicate that, although Zn could be used as a bactericide treatment, it could trigger the undesired effect of stronger biofilm formation upon reinoculation events.
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Affiliation(s)
- Fernando Navarrete
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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Um HY, Kong HG, Lee HJ, Choi HK, Park EJ, Kim ST, Murugiyan S, Chung E, Kang KY, Lee SW. Altered Gene Expression and Intracellular Changes of the Viable But Nonculturable State in Ralstonia solanacearum by Copper Treatment. THE PLANT PATHOLOGY JOURNAL 2013; 29:374-85. [PMID: 25288966 PMCID: PMC4174814 DOI: 10.5423/ppj.oa.07.2013.0067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/08/2013] [Accepted: 08/21/2013] [Indexed: 05/30/2023]
Abstract
Environmental stresses induce several plant pathogenic bacteria into a viable but nonculturable (VBNC) state, but the basis for VBNC is largely uncharacterized. We investigated the physiology and morphology ofthe copper-induced VBNC state in the plant pathogen Ralstonia solanacearum in liquid microcosm. Supplementation of 200 μM copper sulfate to the liquid microcosm completely suppressed bacterial colony formation on culture media; however, LIVE/DEAD BacLight bacterial viability staining showed that the bacterial cells maintained viability, and that the viable cells contain higher level of DNA. Based on electron microscopic observations, the bacterial cells in the VBNC state were unchanged in size, but heavily aggregated and surrounded by an unknown extracellular material. Cellular ribosome contents, however, were less, resulting in a reduction of the total RNA in VBNC cells. Proteome comparison and reverse transcription PCR analysis showed that the Dps protein production was up-regulated at the transcriptional level and that 2 catalases/peroxidases were present at lower level in VBNC cells. Cell aggregation and elevated levels of Dps protein are typical oxidative stress responses. H2O2 levels also increased in VBNC cells, which could result if catalase/peroxidase levels are reduced. Some of phenotypic changes in VBNC cells of R. solanacearum could be an oxidative stress response due to H2O2 accumulation. This report is the first of the distinct phenotypic changes in cells of R. solanacearum in the VBNC state.
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Affiliation(s)
- Hae Young Um
- Department of Medical Bioscience, Dong-A University, Busan 604-714, Korea
| | - Hyun Gi Kong
- Department of Applied Biology, Dong-A University, Busan 604-714, Korea
| | - Hyoung Ju Lee
- Department of Applied Biology, Dong-A University, Busan 604-714, Korea
| | - Hye Kyung Choi
- Department of Medical Bioscience, Dong-A University, Busan 604-714, Korea
| | - Eun Jin Park
- Department of Applied Biology, Dong-A University, Busan 604-714, Korea
| | - Sun Tae Kim
- Department of Plant Bioscience, Pusan National University, Miryang 627-706, Korea
| | | | - Eunsook Chung
- Department of Medical Bioscience, Dong-A University, Busan 604-714, Korea
| | - Kyu Young Kang
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Seon-Woo Lee
- Department of Medical Bioscience, Dong-A University, Busan 604-714, Korea
- Department of Applied Biology, Dong-A University, Busan 604-714, Korea
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Mascher F, Hase C, Bouffaud ML, Défago G, Moënne-Loccoz Y. Cell culturability of Pseudomonas protegens CHA0 depends on soil pH. FEMS Microbiol Ecol 2013; 87:441-50. [PMID: 24224494 DOI: 10.1111/1574-6941.12234] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/30/2013] [Accepted: 09/30/2013] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas inoculants may lose colony-forming ability in soil, but soil properties involved are poorly documented. Here, we tested the hypothesis that soil acidity could reduce persistence and cell culturability of Pseudomonas protegens CHA0. At 1 week in vitro, strain CHA0 was found as culturable cells at pH 7, whereas most cells at pH 4 and all cells at pH 3 were noncultured. In 21 natural soils of contrasted pH, cell culturability loss of P. protegens CHA0 took place in all six very acidic soils (pH < 5.0) and in three of five acidic soils (5.0 < pH < 6.5), whereas it was negligible in the neutral and alkaline soils at 2 weeks and 2 months. No correlation was found between total cell counts of P. protegens CHA0 and soil composition data, whereas colony counts of the strain correlated with soil pH. Maintenance of cell culturability in soils coincided with a reduction in inoculant cell size. Some of the noncultured CHA0 cells were nutrient responsive in Kogure's viability test, both in vitro and in soil. Thus, this shows for the first time that the sole intrinsic soil composition factor triggering cell culturability loss in P. protegens CHA0 is soil acidity.
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Affiliation(s)
- Fabio Mascher
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology, Zürich, Switzerland; Agroscope Changins-Wädenswil research station ACW, Nyon, Switzerland
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Nowakowska J, Oliver JD. Resistance to environmental stresses by Vibrio vulnificus in the viable but nonculturable state. FEMS Microbiol Ecol 2013; 84:213-22. [PMID: 23228034 DOI: 10.1111/1574-6941.12052] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/05/2012] [Accepted: 12/03/2012] [Indexed: 11/29/2022] Open
Abstract
Vibrio vulnificus is responsible for 95% of all seafood-associated fatalities in the United States. When water temperatures drop below c. 13 °C, the cells enter into the viable but nonculturable (VBNC) state wherein they are unable to grow on routine media but retain viability and the ability to return to the culturable state. The aim of this study was to determine whether V. vulnificus cells in the VBNC state are protected against a variety of potentially lethal challenges (heat, oxidative, osmotic, pH, ethanol, antibiotic and heavy metal) and to examine genetic regulators that might underlie such protection. The data presented here indicate that VBNC cells of this pathogen are protected against a wide variety of stresses and retain the ability to return to the culturable state. Surprisingly, we found no significant difference in the expression of relA and spoT between VBNC and logarithmic cells, nor any significant difference in the expression of rpoS in the case of the clinical (C) genotype of this pathogen. However, expression of relA was significantly different in VBNC cells of the environmental (E) genotype compared with logarithmic cells. This might account for findings indicating an enhanced ability for E-genotype cells to withstand environmental changes better than C-genotype cells.
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Affiliation(s)
- Joanna Nowakowska
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
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Erkan M, Sanin FD. Can sludge dewatering reactivate microorganisms in mesophilically digested anaerobic sludge? Case of belt filter versus centrifuge. WATER RESEARCH 2013; 47:428-438. [PMID: 23141737 DOI: 10.1016/j.watres.2012.10.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/10/2012] [Accepted: 10/11/2012] [Indexed: 06/01/2023]
Abstract
The anaerobic digestion process that successfully reduces the organic content of sludge is one of the most common alternatives to meet pathogen reduction requirements for particular classes of biosolids. However, recently it was reported that, much higher densities of indicator bacteria were measured in dewatered cake samples compared to samples collected after anaerobic digestion. Additionally, this increase was commonly observed after centrifugation but not after belt filter dewatering. Several hypotheses were tested to explain this occurrence; however, much of the attention was given to the reactivation of the indicator bacteria which might enter a viable but non-culturable state (VBNC) during digestion. The objective of this research is to examine sludge samples from 5 different full-scale treatment plants in order to observe the effect of dewatering processes on the reactivation potential of indicator bacteria. The bacterial enumerations were performed by both Standard Culturing Methods (SCM) and quantitative polymerase chain (qPCR) on samples collected after digestion and dewatering. Results obtained by SCM indicated that in two investigated treatment plants operating belt filter dewatering, an average 0.6 log decrease was observed after the dewatering process. However, 0.7-1.4 log increases were observed immediately after centrifuge dewatering for the other three treatment plants. On the other hand, qPCR results gave 0.1-1.9 log higher numbers compared to SCM. Comparative evaluation of results obtained by two analytical methods for five treatment plants indicates that the differences observed might be originating from both reactivation of VBNC bacteria and amplification of DNA from dead cells found in the sludge.
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Affiliation(s)
- M Erkan
- Department of Biotechnology, Middle East Technical University, 06800 Ankara, Turkey
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Molina LG, da Fonseca GC, de Morais GL, de Oliveira LFV, de Carvalho JB, Kulcheski FR, Margis R. Metatranscriptomic analysis of small RNAs present in soybean deep sequencing libraries. Genet Mol Biol 2012; 35:292-303. [PMID: 22802714 PMCID: PMC3392881 DOI: 10.1590/s1415-47572012000200010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A large number of small RNAs unrelated to the soybean genome were identified after deep sequencing of soybean small RNA libraries. A metatranscriptomic analysis was carried out to identify the origin of these sequences. Comparative analyses of small interference RNAs (siRNAs) present in samples collected in open areas corresponding to soybean field plantations and samples from soybean cultivated in greenhouses under a controlled environment were made. Different pathogenic, symbiotic and free-living organisms were identified from samples of both growth systems. They included viruses, bacteria and different groups of fungi. This approach can be useful not only to identify potentially unknown pathogens and pests, but also to understand the relations that soybean plants establish with microorganisms that may affect, directly or indirectly, plant health and crop production.
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Affiliation(s)
- Lorrayne Gomes Molina
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Guilherme Cordenonsi da Fonseca
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Guilherme Loss de Morais
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Luiz Felipe Valter de Oliveira
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Joseane Biso de Carvalho
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Franceli Rodrigues Kulcheski
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rogerio Margis
- Centro de Biotecnologia e PPGBCM, Laboratório de Genomas e Populações de Plantas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Departamento de Biofísica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Trevors JT, Bej AK, Mojib N, van Elsas JD, Van Overbeek L. Bacterial gene expression at low temperatures. Extremophiles 2012; 16:167-76. [PMID: 22212655 DOI: 10.1007/s00792-011-0423-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 12/13/2011] [Indexed: 01/26/2023]
Abstract
Under suboptimal environmental conditions such as low temperatures, many bacteria have an extended lag phase, altered cell structures, and composition such as a less fluid (more rigid) and leaky cytoplasmic membrane. As a result, cells may die, enter into a starvation mode of metabolism or a physiologically viable but non-culturable (VBNC) state. In the latter state, the amount of gene expression per cell is virtually undetectable. In this article, gene expression under (suboptimal) low temperature conditions in non-psychrophilic environmental bacteria is examined. The pros and cons of some of the molecular methodologies for gene expression analysis are also discussed.
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Affiliation(s)
- J T Trevors
- Laboratory of Microbiology, School of Environmental Sciences, Rm. 3220 Bovey Bldg., University of Guelph, Guelph, ON, N1G 2W1, Canada.
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Dwidjosiswojo Z, Richard J, Moritz MM, Dopp E, Flemming HC, Wingender J. Influence of copper ions on the viability and cytotoxicity of Pseudomonas aeruginosa under conditions relevant to drinking water environments. Int J Hyg Environ Health 2011; 214:485-92. [DOI: 10.1016/j.ijheh.2011.06.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 06/10/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
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