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Wei Y, Dong B, Wu X, Zhao M, Wang D, Li N, Zhang Q, Zhang L, Zhou H. RpoZ regulates 2,4-DAPG production and quorum sensing system in Pseudomonas fluorescens 2P24. Front Microbiol 2023; 14:1160913. [PMID: 37250031 PMCID: PMC10213339 DOI: 10.3389/fmicb.2023.1160913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/26/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction Pseudomonas fluorescens 2P24 was isolated from soil of natural decay associated with wheat take-all and it can effectively control soil-borne diseases caused by a variety of plant pathogens. 2,4-diacetylphloroglucinol (2,4-DAPG), is produced by P. fluorescens 2P24 and plays an important role in the prevention and control of plant diseases. To understand the resistant mechanism, in this study, we conducted experiments to explore the regulation role of rpoZ in the synthesis of the antibiotic 2,4-DAPG and regulation of QS system. Methods A random mini-Tn5 mutagenesis procedure was used to screen regulators for phlA transcription in stain PM901, which containing a phlA∷lacZ transcriptional fusion reporter plasmid. We identified 12 insertion mutants could significantly change phlA gene expression. By analyzing the amino acid sequences of the interrupted gene, we obtained a mutant strain Aa4-29 destroyed the rpoZ gene, which encodes the omiga subunit. We constructed the plasmid of rpoZ mutant (pBBR-△rpoZ) transformed into competent cells of P. fluorescens 2P24 by electro-transformation assay. The strains of P. fluorescens 2P24/pBBR, 2P24-△rpoZ/pBBR, 2P24-△rpoZ/pBBR-rpoZ were used to evaluate the regulation role of rpoZ in 2,4-DAPG production and quorum sensing system. Results According to β-galactosidase activity, we found that rpoZ positively regulated the expression of phlA (a synthesis gene of 2,4-DAPG) and PcoI (a synthesis gene of PcoI/PcoR QS signal system) at the transcriptional level. The production of 2,4-DAPG antibiotic and signal molecule AHL was influenced by rpoZ. Further, rpoZ was involved in regulating rsmA expression. RpoZ also has a certain regulatory effect on rpoS transcription, but no effect on the transcription of phlF, emhABC and emhR. According to the biocontrol assay, P. fluorescens 2P24 strains with rpoZ showed obvious antagonism ability against the Rhizoctonia solani in cotton, while the mutant strain of rpoZ lost the biocontrol effect. RpoZ had a significant effect on the swimming and biofilm formation in P. fluorescens 2P24. Conclusion Our data showed that rpoZ was an important regulator of QS system, 2,4-DAPG in P. fluorescens 2P24. This may imply that P. fluorescens 2P24 has evolved different regulatory features to adapt to different environmental threats.
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Affiliation(s)
- Yarui Wei
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Baozhu Dong
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, China
| | - Mingmin Zhao
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Dong Wang
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
| | - Na Li
- Erdos Agricultural and Animal Husbandry Technology Promotion Center, Erdos, Inner Mongolia, China
| | - Qian Zhang
- Bayannaoer Agriculture and Animal Husbandry Technology Promotion Center, Bayannaoer, Inner Mongolia, China
| | - Liqun Zhang
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Hongyou Zhou
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China
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Wang J, Wang Y, Lou H, Wang W. AlgU controls environmental stress adaptation, biofilm formation, motility, pyochelin synthesis and antagonism potential in Pseudomonas protegens SN15-2. Microbiol Res 2023; 272:127396. [PMID: 37141849 DOI: 10.1016/j.micres.2023.127396] [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: 03/16/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023]
Abstract
Pseudomonas protegens is a typical plant-growth-promoting rhizobacterium that can serve as an agricultural biocontrol agent. The extracytoplasmic function (ECF) sigma factor AlgU is a global transcription regulator controlling stress adaption and virulence in Pseudomonas aeruginosa and Pseudomonas syringae. Meanwhile, the regulatory role of AlgU in the biocontrol ability of P.protegens has been poorly studied. In this study, deletion mutations of algU and its antagonist coding gene mucA were constructed to investigate the function of AlgU in P.protegens SN15-2 via phenotypic experiment and transcriptome sequencing analysis. On the basis of phenotypic analyses, it was concluded that the AlgU whose transcription was induced by osmotic stress and oxidative stress positively regulated biofilm formation and tolerance towards osmotic, heat, and oxidation stresses, while it negatively regulated motility, pyochelin synthesis, and the ability to inhibit pathogens. On the basis of the RNA-seq analysis, compared to the wild-type strain, 12 genes were significantly upregulated and 77 genes were significantly downregulated in ΔalgU, while 407 genes were significantly upregulated and 279 genes were significantly downregulated in ΔmucA, indicating the involvement of AlgU in several cellular processes, mainly related to resistance, carbohydrate metabolism, membrane formation, alginate production, the type VI secretion system, flagella motility and pyochelin production. Our findings provide insights into the important role of AlgU of P.protegens in biocontrol, which is of value in improving the biocontrol ability of P.protegens.
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Affiliation(s)
- Jian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yaping Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haibo Lou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
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Yang R, Shi Q, Huang T, Yan Y, Li S, Fang Y, Li Y, Liu L, Liu L, Wang X, Peng Y, Fan J, Zou L, Lin S, Chen G. The natural pyrazolotriazine pseudoiodinine from Pseudomonas mosselii 923 inhibits plant bacterial and fungal pathogens. Nat Commun 2023; 14:734. [PMID: 36759518 PMCID: PMC9911603 DOI: 10.1038/s41467-023-36433-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
Natural products largely produced by Pseudomonads-like soil-dwelling microorganisms are a consistent source of antimicrobial metabolites and pesticides. Herein we report the isolation of Pseudomonas mosselii strain 923 from rice rhizosphere soils of paddy fields, which specifically inhibit the growth of plant bacterial pathogens Xanthomonas species and the fungal pathogen Magnaporthe oryzae. The antimicrobial compound is purified and identified as pseudoiodinine using high-resolution mass spectra, nuclear magnetic resonance and single-crystal X-ray diffraction. Genome-wide random mutagenesis, transcriptome analysis and biochemical assays define the pseudoiodinine biosynthetic cluster as psdABCDEFG. Pseudoiodinine biosynthesis is proposed to initiate from guanosine triphosphate and 1,6-didesmethyltoxoflavin is a biosynthetic intermediate. Transposon mutagenesis indicate that GacA is the global regulator. Furthermore, two noncoding small RNAs, rsmY and rsmZ, positively regulate pseudoiodinine transcription, and the carbon storage regulators CsrA2 and CsrA3, which negatively regulate the expression of psdA. A 22.4-fold increase in pseudoiodinine production is achieved by optimizing the media used for fermentation, overexpressing the biosynthetic operon, and removing the CsrA binding sites. Both of the strain 923 and purified pseudoiodinine in planta inhibit the pathogens without affecting the rice host, suggesting that pseudoiodinine can be used to control plant diseases.
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Affiliation(s)
- Ruihuan Yang
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Qing Shi
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tingting Huang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yichao Yan
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shengzhang Li
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yuan Fang
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ying Li
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Linlin Liu
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Longyu Liu
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaozheng Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yongzheng Peng
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiangbo Fan
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lifang Zou
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China. .,State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Shuangjun Lin
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Gongyou Chen
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China. .,State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Huang X, Luo Y, Luo L, Xie D, Li Z. The nitrite reductase encoded by nirBDs in Pseudomonas putida Y-9 influences ammonium transformation. Front Microbiol 2022; 13:982674. [PMID: 36312953 PMCID: PMC9597696 DOI: 10.3389/fmicb.2022.982674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/21/2022] [Indexed: 09/13/2023] Open
Abstract
It is unknown whether nirBDs, which conventionally encode an NADH nitrite reductase, play other novel roles in nitrogen cycling. In this study, we explored the role of nirBDs in the nitrogen cycling of Pseudomonas putida Y-9. nirBDs had no effect on organic nitrogen transformation by strain Y-9. The △nirBD strain exhibited higher ammonium removal efficiency (90.7%) than the wild-type strain (76.1%; P < 0.05) and lower end gaseous nitrogen (N2O) production. Moreover, the expression of glnA (control of the ammonium assimilation) in the △nirBD strain was higher than that in the wild-type strain (P < 0.05) after being cultured in ammonium-containing medium. Furthermore, nitrite noticeably inhibited the ammonium elimination of the wild-type strain, with a corresponding removal rate decreasing to 44.8%. However, no similar impact on ammonium transformation was observed for the △nirBD strain, with removal efficiency reaching 97.5%. In conclusion, nirBDs in strain Y-9 decreased the ammonium assimilation and increased the ammonium oxidation to nitrous oxide.
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Affiliation(s)
- Xuejiao Huang
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
- Guangxi Bossco Environmental Protection Technology Co., Ltd., Nanning, China
| | - Yuwen Luo
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
| | - Luo Luo
- Key Laboratory of (Guangxi) Agricultural Environment and Products Safety, College of Agronomy, Guangxi University, Nanning, China
| | - Deti Xie
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
| | - Zhenlun Li
- Chongqing Key Laboratory of Soil Multiscale Interfacial Process, Southwest University, Chongqing, China
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Gu Q, Qiao J, Wang R, Lu J, Wang Z, Li P, Zhang L, Ali Q, Khan AR, Gao X, Wu H. The Role of Pyoluteorin from Pseudomonas protegens Pf-5 in Suppressing the Growth and Pathogenicity of Pantoea ananatis on Maize. Int J Mol Sci 2022; 23:ijms23126431. [PMID: 35742879 PMCID: PMC9223503 DOI: 10.3390/ijms23126431] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 01/24/2023] Open
Abstract
The rhizospheric bacterium Pseudomonas protegens Pf-5 can colonize the seed and root surfaces of plants, and can protect them from pathogen infection. Secondary metabolites, including lipopeptides and polyketides produced by Pf-5, are involved in its biocontrol activity. We isolated a crude extract from Pf-5. It exhibited significant surface activity and strong antibacterial activity against Pantoea ananatis DZ-12, which causes maize brown rot on leaves. HPLC analysis combined with activity tests showed that the polyketide pyoluteorin in the crude extract participated in the suppression of DZ-12 growth, and that the lipopeptide orfamide A was the major biosurfactant in the crude extract. Further studies indicated that the pyoluteorin in the crude extract significantly suppressed the biofilm formation of DZ-12, and it induced the accumulation of reactive oxygen species in DZ-12 cells. Scanning electron microscopy and transmission electron microscopy observation revealed that the crude extract severely damaged the pathogen cells and caused cytoplasmic extravasations and hollowing of the cells. The pathogenicity of DZ-12 on maize leaves was significantly reduced by the crude extract from Pf-5 in a dose-dependent manner. The polyketide pyoluteorin had strong antibacterial activity against DZ-12, and it has the potential for development as an antimicrobial agent.
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Affiliation(s)
- Qin Gu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Junqing Qiao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China;
| | - Ruoyi Wang
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Juan Lu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Zhengqi Wang
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Pingping Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Lulu Zhang
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Qurban Ali
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Abdur Rashid Khan
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Xuewen Gao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
| | - Huijun Wu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; (Q.G.); (R.W.); (J.L.); (Z.W.); (P.L.); (L.Z.); (Q.A.); (A.R.K.); (X.G.)
- Correspondence: ; Tel./Fax: +86-25-84395268
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Fus3, as a Critical Kinase in MAPK Cascade, Regulates Aflatoxin Biosynthesis by Controlling the Substrate Supply in Aspergillus flavus, Rather than the Cluster Genes Modulation. Microbiol Spectr 2022; 10:e0126921. [PMID: 35107358 PMCID: PMC8809346 DOI: 10.1128/spectrum.01269-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Fus3-MAP kinase module is a conserved phosphorylation signal system in eukaryotes that responds to environmental stress and transduction of external signals from the outer membrane to the nucleus. Aspergillus flavus can produce aflatoxins (AF), which seriously threaten human and animal health. In this study, we determined the functions of Fus3, confirmed Ste50-Ste11-Ste7-Fus3 protein interactions and phosphorylation, and explored the possible phosphorylation motifs and potential targets of Fus3. The regulatory mechanism of Fus3 on the biosynthesis of AF was partly revealed in this study. AF production was downregulated in Δfus3, but the transcriptional expression of most AF cluster genes was upregulated. It is notable that the levels of acetyl-CoA and malonyl-CoA, the substrates of AF, were significantly decreased in fus3 defective strains. Genes involved in acetyl-CoA and malonyl-CoA biosynthesis were significantly downregulated at transcriptional or phosphorylation levels. Specifically, AccA might be a direct target of Fus3, which led to acetyl-CoA carboxylase activities were decreased in null-deletion and site mutagenesis strains. The results concluded that Fus3 could regulate the expression of acetyl-CoA and malonyl-CoA biosynthetic genes directly or indirectly, and then affect the AF production that relies on the regulation of AF substrate rather than the modulation of AF cluster genes. IMPORTANCEAspergillus flavus is an important saprophytic fungus that produces aflatoxins (AF), which threaten food and feed safety. MAP (mitogen-activated protein) kanases are essential for fungal adaptation to diverse environments. Fus3, as the terminal kinase of a MAPK cascade, interacts with other MAPK modules and phosphorylates downstream targets. We provide evidence that Fus3 could affect AF biosynthesis by regulating the production of acetyl-CoA and malonyl-CoA, but this does not depend on the regulation of AF biosynthetic genes. Our results partly reveal the regulatory mechanism of Fus3 on AF biosynthesis and provide a novel AF modulation pattern, which may contribute to the discovery of new strategies in controlling A. flavus and AF contamination.
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Choline–betaine pathway contributes to hyperosmotic stress and subsequent lethal stress resistance in Pseudomonas protegens SN15-2. J Biosci 2020. [DOI: 10.1007/s12038-020-00060-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Zhang B, Zhao H, Wu X, Zhang LQ. The Oxidoreductase DsbA1 negatively influences 2,4-diacetylphloroglucinol biosynthesis by interfering the function of Gcd in Pseudomonas fluorescens 2P24. BMC Microbiol 2020; 20:39. [PMID: 32093646 PMCID: PMC7041245 DOI: 10.1186/s12866-020-1714-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/27/2020] [Indexed: 02/03/2023] Open
Abstract
Background The polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG), produced by Pseudomonas fluorescens 2P24, is positively regulated by the GacS-GacA two-component system. Results Here we reported on the characterization of DsbA1 (disulfide oxidoreductase) as novel regulator of biocontrol activity in P. fluorescens. Our data showed that mutation of dsbA1 caused the accumulation of 2,4-DAPG in a GacA-independent manner. Further analysis indicated that DsbA1 interacts with membrane-bound glucose dehydrogenase Gcd, which positively regulates the production of 2,4-DAPG. Mutation of cysteine (C)-235, C275, and C578 of Gcd, significantly reduced the interaction with DsbA1, enhanced the activity of Gcd and increased 2,4-DAPG production. Conclusions Our results suggest that DsbA1 regulates the 2,4-DAPG concentration via fine-tuning the function of Gcd in P. fluorescens 2P24.
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Affiliation(s)
- Bo Zhang
- College of Agriculture, Guangxi University, Nanning, 530004, China
| | - Hui Zhao
- College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, 530004, China.
| | - Li-Qun Zhang
- College of Plant Protection, China Agricultural University, Beijing, 100193, China.
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Otero-Asman JR, Wettstadt S, Bernal P, Llamas MA. Diversity of extracytoplasmic function sigma (σ ECF ) factor-dependent signaling in Pseudomonas. Mol Microbiol 2019; 112:356-373. [PMID: 31206859 DOI: 10.1111/mmi.14331] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2019] [Indexed: 12/23/2022]
Abstract
Pseudomonas bacteria are widespread and are found in soil and water, as well as pathogens of both plants and animals. The ability of Pseudomonas to colonize many different environments is facilitated by the multiple signaling systems these bacteria contain that allow Pseudomonas to adapt to changing circumstances by generating specific responses. Among others, signaling through extracytoplasmic function σ (σECF ) factors is extensively present in Pseudomonas. σECF factors trigger expression of functions required under particular conditions in response to specific signals. This manuscript reviews the phylogeny and biological roles of σECF factors in Pseudomonas, and highlights the diversity of σECF -signaling pathways of this genus in terms of function and activation. We show that Pseudomonas σECF factors belong to 16 different phylogenetic groups. Most of them are included within the iron starvation group and are mainly involved in iron acquisition. The second most abundant group is formed by RpoE-like σECF factors, which regulate the responses to cell envelope stress. Other groups controlling solvent tolerance, biofilm formation and the response to oxidative stress, among other functions, are present in lower frequency. The role of σECF factors in the virulence of Pseudomonas pathogenic species is described.
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Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Sarah Wettstadt
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Patricia Bernal
- Department of Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
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Hashemi MM, Holden BS, Coburn J, Taylor MF, Weber S, Hilton B, Zaugg AL, McEwan C, Carson R, Andersen JL, Price JC, Deng S, Savage PB. Proteomic Analysis of Resistance of Gram-Negative Bacteria to Chlorhexidine and Impacts on Susceptibility to Colistin, Antimicrobial Peptides, and Ceragenins. Front Microbiol 2019; 10:210. [PMID: 30833936 PMCID: PMC6388577 DOI: 10.3389/fmicb.2019.00210] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/24/2019] [Indexed: 12/19/2022] Open
Abstract
Use of chlorhexidine in clinical settings has led to concerns that repeated exposure of bacteria to sub-lethal doses of chlorhexidine might result in chlorhexidine resistance and cross resistance with other cationic antimicrobials including colistin, endogenous antimicrobial peptides (AMPs) and their mimics, ceragenins. We have previously shown that colistin-resistant Gram-negative bacteria remain susceptible to AMPs and ceragenins. Here, we investigated the potential for cross resistance between chlorhexidine, colistin, AMPs and ceragenins by serial exposure of standard strains of Gram-negative bacteria to chlorhexidine to generate resistant populations of organisms. Furthermore, we performed a proteomics study on the chlorhexidine-resistant strains and compared them to the wild-type strains to find the pathways by which bacteria develop resistance to chlorhexidine. Serial exposure of Gram-negative bacteria to chlorhexidine resulted in four- to eight-fold increases in minimum inhibitory concentrations (MICs). Chlorhexidine-resistant organisms showed decreased susceptibility to colistin (8- to 32-fold increases in MICs) despite not being exposed to colistin. In contrast, chlorhexidine-resistant organisms had the same MICs as the original strains when tested with representative AMPs (LL-37 and magainin I) and ceragenins (CSA-44 and CSA-131). These results imply that there may be a connection between the emergence of highly colistin-resistant Gram-negative pathogens and the prevalence of chlorhexidine usage. Yet, use of chlorhexidine may not impact innate immune defenses (e.g., AMPs) and their mimics (e.g., ceragenins). Here, we also show that chlorhexidine resistance is associated with upregulation of proteins involved in the assembly of LPS for outer membrane biogenesis and virulence factors in Pseudomonas aeruginosa. Additionally, resistance to chlorhexidine resulted in elevated expression levels of proteins associated with chaperones, efflux pumps, flagella and cell metabolism. This study provides a comprehensive overview of the evolutionary proteomic changes in P. aeruginosa following exposure to chlorhexidine and colistin. These results have important clinical implications considering the continuous application of chlorhexidine in hospitals that could influence the emergence of colistin-resistant strains.
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Affiliation(s)
- Marjan M Hashemi
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Brett S Holden
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Jordan Coburn
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Maddison F Taylor
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Scott Weber
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Brian Hilton
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Aaron L Zaugg
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Colten McEwan
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Richard Carson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Joshua L Andersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - John C Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Shenglou Deng
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Paul B Savage
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
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Kenawy A, Dailin DJ, Abo-Zaid GA, Malek RA, Ambehabati KK, Zakaria KHN, Sayyed RZ, El Enshasy HA. Biosynthesis of Antibiotics by PGPR and Their Roles in Biocontrol of Plant Diseases. PLANT GROWTH PROMOTING RHIZOBACTERIA FOR SUSTAINABLE STRESS MANAGEMENT 2019:1-35. [DOI: 10.1007/978-981-13-6986-5_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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