1
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Xu Q, Gao S, Zhang S, Li K, Guo Y. Disruption of the cell division protein ftsK gene changes elemental selenium generation, selenite tolerance, and cell morphology in Rahnella aquatilis HX2. J Appl Microbiol 2024; 135:lxae142. [PMID: 38871681 DOI: 10.1093/jambio/lxae142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 05/31/2024] [Accepted: 06/12/2024] [Indexed: 06/15/2024]
Abstract
AIMS Some studies have indicated that the alterations in cellular morphology induced by selenite [Se(Ⅳ)] may be attributed to its inhibitory effects on cell division. However, whether the genes associated with cell division are implicated in Se(Ⅳ) metabolism remains unclear. METHODS AND RESULTS The ftsK gene in Rahnella aquatilis HX2 was mutated with an in-frame deletion strategy. The ftsK mutation strongly reduced the tolerance to selenite [Se(Ⅳ)] and the production of red elemental selenium [Se(0)] in R. aquatilis HX2, and this effect could not be attributed solely to the inhibition of cell growth. Deleting the ftsK gene also resulted in a significant decrease in bacterial growth of R. aquatilis HX2 during both exponential and stationary phases. The deletion of ftsK inhibited cell division, resulting in the development of elongated filamentous cells. Furthermore, the loss-of-function of FtsK significantly impacted the expression of seven genes linked to cell division and Se(Ⅳ) metabolism by at least 2-fold, as unveiled by real-time quantitative PCR (RT-qPCR) under Se(Ⅳ) treatment. CONCLUSIONS These findings suggest that FtsK is associated with Se(Ⅳ) tolerance and Se(0) generation and is a key player in coordinating bacterial growth and cell morphology in R. aquatilis HX2.
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Affiliation(s)
- Qiaolin Xu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Shanshan Gao
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Sasa Zhang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Kui Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Yanbin Guo
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
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2
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Peng J, Xu Z, Li L, Zhao B, Guo Y. Disruption of the sensor kinase phoQ gene decreases acid resistance in plant growth-promoting rhizobacterium Rahnella aquatilis HX2. J Appl Microbiol 2023; 134:6991427. [PMID: 36748653 DOI: 10.1093/jambio/lxad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/24/2022] [Accepted: 01/17/2023] [Indexed: 01/20/2023]
Abstract
AIMS Rahnella aquatilis HX2, a promising plant growth-promoting rhizobacterium (PGPR) in the field, contains genes homologous to the PhoP/PhoQ two-component regulatory system. Although this system regulates stress response in numerous pathogens, PhoP/PhoQ characterization in a PGPR has not received in-depth exploration. METHODS AND RESULTS The phoQ gene was mutated in strain HX2 using an in-frame deletion strategy. Compared to the wild type, the phoQ mutant exhibited increased sensitivity to acidic conditions (pH 4.0) in a chemically defined medium and in mild acidic natural soil (pH 5.7). The phoQ mutant also exhibited increased swimming motility under acidic conditions. Acid resistance was restored in the mutant by introducing the phoQ gene on a plasmid. Three acid resistance genes, add, cfa, and fur were downregulated significantly, whereas the chaperone encoding gene, dnak, was upregulated when the phoQ mutant was exposed to acid stress. CONCLUSIONS This study suggested that the PhoP/PhoQ system positively regulates the acid resistance of R. aquatilis HX2.
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Affiliation(s)
- Jing Peng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Zhongnan Xu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Lei Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Institute of Vegetables and Flowers, Chinese Academy of Agricultural Science, Beijing 100081, China
| | - Bingjie Zhao
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Yanbin Guo
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.,Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
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3
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Xu Q, Zhang S, Ren J, Li K, Li J, Guo Y. Uptake of Selenite by Rahnella aquatilis HX2 Involves the Aquaporin AqpZ and Na +/H + Antiporter NhaA. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2371-2379. [PMID: 36734488 DOI: 10.1021/acs.est.2c07028] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microbial transformation of selenite [Se(IV)] to elemental selenium nanoparticles (SeNPs) is known to be an important process for removing toxic soluble selenium (Se) oxyanions and recovery of Se from the environment as valuable nanoparticles. However, the mechanism of selenite uptake by microorganisms, the first step through which Se exerts its cellular function, remains not well studied. In this study, the effects of selenite concentration, time, pH, metabolic inhibitors, and anionic analogues on selenite uptake in Rahnella aquatilis HX2 were investigated. Selenite uptake by R. aquatilis HX2 was concentration- and time-dependent, and its transport activity was significantly dependent on pH. In addition, selenite uptake in R. aquatilis HX2 was significantly inhibited by the aquaporin inhibitor AgNO3 and sulfite (SO32-), and partially inhibited by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 2,4-dinitrophenol (2,4-DNP) treatments. Three mutants with in-frame deletions of aqpZ, glpF, and nhaA genes were constructed. The transport assay showed that the water channel protein AqpZ, and not GlpF, was a key channel of selenite uptake by R. aquatilis HX2, and sulfite and selenite had a common uptake pathway. In addition, the Na+/H+ antiporter NhaA is also involved in selenite uptake in R. aquatilis HX2.
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Affiliation(s)
- Qiaolin Xu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Sasa Zhang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Jing Ren
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Kui Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Jing Li
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
| | - Yanbin Guo
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing 100193, China
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4
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Duan S, Declerck S, Feng G, Zhang L. Hyphosphere interactions between Rhizophagus irregularis and Rahnella aquatilis promote carbon-phosphorus exchange at the peri-arbuscular space in Medicago truncatula. Environ Microbiol 2023; 25:867-879. [PMID: 36588345 DOI: 10.1111/1462-2920.16333] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi form a continuum between roots and soil. One end of this continuum is comprised of the highly intimate plant-fungus interface with intracellular organelles for nutrient exchange, while on the other end the fungus interacts with bacteria to compensate for the AM fungus' inability to take up organic nutrients from soil. How both interfaces communicate in this highly complex tripartite mutualism is widely unknown. Here, the effects of phosphate-solubilizing bacteria (PSB) Rahnella aquatilis dwelling at the surface of the extraradical hyphae of Rhizophagus irregularis was analysed based on the expression of genes involved in C-P exchange at the peri-arbuscular space (PAS) in Medicago truncatula. The interaction between AM fungus and PSB resulted in an increase in uptake and transport of Pi along the extraradical hyphae and its transfer from AM fungus to plant. In return, this was remunerated by a transfer of C from plant to AM fungus, improving the C-P exchange at the PAS. These results demonstrated that a microorganism (i.e., a PSB) developing at the hyphosphere interface can affect the C-P exchange at the PAS between plant and AM fungus, suggesting a fine-tuned communication operated between three organisms via two distantly connected interfaces.
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Affiliation(s)
- Shilong Duan
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.,Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing, China.,National Observation and Research Station of Agriculture Green Development (Quzhou, Hebei), China Agricultural University, Beijing, China
| | - Stéphane Declerck
- Université catholique de Louvain, Earth and Life Institute, Applied Microbiology, Mycology, Louvain-la-Neuve, Belgium
| | - Gu Feng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.,Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing, China.,National Observation and Research Station of Agriculture Green Development (Quzhou, Hebei), China Agricultural University, Beijing, China
| | - Lin Zhang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.,Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing, China.,National Observation and Research Station of Agriculture Green Development (Quzhou, Hebei), China Agricultural University, Beijing, China
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5
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Xu S, Zhao Y, Peng Y, Shi Y, Xie X, Chai A, Li B, Li L. Comparative Genomics Assisted Functional Characterization of Rahnella aceris ZF458 as a Novel Plant Growth Promoting Rhizobacterium. Front Microbiol 2022; 13:850084. [PMID: 35444623 PMCID: PMC9015054 DOI: 10.3389/fmicb.2022.850084] [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: 01/07/2022] [Accepted: 02/24/2022] [Indexed: 11/25/2022] Open
Abstract
Many Rahnella strains have been widely described as plant growth-promoting rhizobacteria with the potential to benefit plant growth and protect plants from pathogens. R. aceris ZF458 is a beneficial plant bacterium isolated from swamp soil with the potential for biocontrol. Strain ZF458 has shown broad-spectrum antagonistic activities against a variety of plant pathogens and exhibited a dramatic effect on controlling Agrobacterium tumefaciens in sunflowers. The R. aceris ZF458 genome sequence contained a 4,861,340-bp circular chromosome and two plasmids, with an average G + C content of 52.20%. Phylogenetic analysis demonstrated that R. aceris ZF458 was closely related to R. aceris SAP-19. Genome annotation and comparative genomics identified the conservation and specificity of large numbers of genes associated with nitrogen fixation, plant growth hormone production, organic acid biosynthesis and pyrroloquinoline quinone production that specific to benefiting plants in strain ZF458. In addition, numerous conserved genes associated with environmental adaption, including the bacterial secretion system, selenium metabolism, two-component system, flagella biosynthesis, chemotaxis, and acid resistance, were also identified in the ZF458 genome. Overall, this was the first study to systematically analyze the genes linked with plant growth promotion and environmental adaption in R. aceris. The aim of this study was to derive genomic information that would provide an in-depth insight of the mechanisms of plant growth-promoting rhizobacteria, and could be further exploited to improve the application of R. aceris ZF458 in the agriculture field.
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Affiliation(s)
- Shuai Xu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yurong Zhao
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yue Peng
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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6
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Duan S, Declerck S, Zhang L, Feng G. Two-component system in Rahnella aquatilis is impacted by the hyphosphere of the arbuscular mycorrhizal fungus Rhizophagus irregularis. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:119-129. [PMID: 34951128 DOI: 10.1111/1758-2229.13039] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Two-component systems (TCS) are ubiquitous among bacteria, playing key roles in signalling events. However, to what extent the TCS of Rahnella aquatilis (a Phosphate solubilizing bacteria) is influenced by the hyphosphere of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis is totally unknown. Here, the expression of 16 genes encoding the TCS of R. aquatilis (i.e. involved in carbon-sensing and nutrient-sensing) and of eight genes regulated by the PhoR TCS (i.e. involved in inorganic and organic phosphorus mobilization) were analysed at regular intervals in presence of hyphae of R. irregularis. The study was conducted under in vitro culture conditions with phytate as the unique source of phosphorus. In presence of the AM fungus, the expression of TCS genes involved in carbon-sensing and nutrient-sensing were stimulated. Only, BaeS at 30 and 120 min, and BaeR at 60 min were inhibited. In addition, the PhoR TCS stimulated the expression of genes encoding phosphatase but inhibited the expression of genes involved in gluconic acid production. As the mechanism of coupling environmental changes with cellular physiological changes, TCS plays a pivotal role in regulating specific gene expression in R. aquatilis, recognizing environmental signals. More importantly, TCS genes may regulate bacteria response to hyphal carbon to mobilize phosphorus efficiently in the hyphosphere.
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Affiliation(s)
- Shilong Duan
- College of Resources and Environmental Sciences, MOE Key Laboratory of Plant-Soil Interactions, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 10093, China
| | - Stéphane Declerck
- Université Catholique de Louvain, Earth and Life Institute, Applied Microbiology, Mycology, Croix du Sud 2, bte L7.05.06, Louvain-la-Neuve, B-1348, Belgium
| | - Lin Zhang
- College of Resources and Environmental Sciences, MOE Key Laboratory of Plant-Soil Interactions, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 10093, China
| | - Gu Feng
- College of Resources and Environmental Sciences, MOE Key Laboratory of Plant-Soil Interactions, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 10093, China
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7
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GENOME ANALYSIS OF Pseudomonas brassicacearum S-1 – AN ANTAGONIST OF CROP PATHOGENS. BIOTECHNOLOGIA ACTA 2021. [DOI: 10.15407/biotech14.02.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The strain Pseudomonas brassicacearum S-1 is the basis of the biopesticide “Ecogreen”, which is used to control pathogens infecting vegetable and green spicy crops in small-scale hydroponics. Aim. The purpose of this work was to sequence and analyze the nucleotide sequence of the genome of strain P. brassicacearum S-1 (GenBank accession number CP045701). Methods. Whole-genome sequencing was performed by both MiSeq (Illuminа) and MinION (Oxford Nanopore). Analysis of the genome sequence was performed with a number of bioinformatics programs. Results. The genome of the P. brassicacearum S-1 strain comprising a single circular 6 577 561-bp chromosome with GC content of 60.8 %. Genome analysis revealed genes that constitute valuable biotechnological potential of the S-1 strain and determine synthesis of a wide range of secondary metabolites. Moreover, mobile genetic elements, prophages and short repetitive sequences were identified in the S-1 genome. Conclusions. Detected genetic determinants, which are responsible for the synthesis of practically valuable compounds, indicate a significant potential of the P. brassicacearum S-1 strain as a biocontrol agent.
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8
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Chen L, Wang X, Ma Q, Bian L, Liu X, Xu Y, Zhang H, Shao J, Liu Y. Bacillus velezensis CLA178-Induced Systemic Resistance of Rosa multiflora Against Crown Gall Disease. Front Microbiol 2020; 11:587667. [PMID: 33193244 PMCID: PMC7642876 DOI: 10.3389/fmicb.2020.587667] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/28/2020] [Indexed: 01/07/2023] Open
Abstract
Plant growth-promoting rhizobacteria (PGPRs) are able to activate induced systemic resistance (ISR) of the plants against phytopathogens. However, whether and how ISR can be activated by PGPRs in plants of the Rosa genus is unclear. The effects of PGPR Bacillus velezensis CLA178 and the pathogen Agrobacterium tumefaciens C58 on the growth, plant defense-related genes, hormones, and reactive oxygen species (ROS) in the rose plants were compared. Pretreatment with CLA178 significantly reduced crown gall tumor biomass and relieved the negative effects of the C58 pathogen on plant biomass, chlorophyll content, and photosynthesis of roses. Pretreatment of the roots with CLA178 activated ISR and significantly reduced disease severity. Pretreatment with CLA178 enhanced plant defense response to C58, including the accumulation of ROS, antioxidants, and plant hormones. Moreover, pretreatment with CLA178 enhanced C58-dependent induction of the expression of the genes related to the salicylic acid (SA) or ethylene (ET) signaling pathways. This result suggested that SA- and ET-signaling may participate in CLA178-mediated ISR in roses. Additional experiments in the Arabidopsis mutants showed that CLA178 triggered ISR against C58 in the pad4 and jar1 mutants and not in the etr1 and npr1 mutants. The ISR phenotypes of the Arabidopsis mutants indicated that CLA178-mediated ISR is dependent on the ET-signaling pathway in an NPR1-dependent manner. Overall, this study provides useful information to expand the application of PGPRs to protect the plants of the Rosa genus from phytopathogens.
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Affiliation(s)
- Lin Chen
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Xinghong Wang
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Qinghua Ma
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Lusen Bian
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Xue Liu
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Yan Xu
- Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing, China
| | - Huihui Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Jiahui Shao
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yunpeng Liu
- Key Laboratory of Agricultural Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
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9
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The small RNA chaperone Hfq is a critical regulator for bacterial biosynthesis of selenium nanoparticles and motility in Rahnella aquatilis. Appl Microbiol Biotechnol 2020; 104:1721-1735. [DOI: 10.1007/s00253-019-10231-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/11/2019] [Accepted: 10/31/2019] [Indexed: 02/08/2023]
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10
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Yuan L, Li L, Zheng F, Shi Y, Xie X, Chai A, Li B. The complete genome sequence of Rahnella aquatilis ZF7 reveals potential beneficial properties and stress tolerance capabilities. Arch Microbiol 2019; 202:483-499. [PMID: 31707426 DOI: 10.1007/s00203-019-01758-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/08/2019] [Accepted: 10/25/2019] [Indexed: 01/28/2023]
Abstract
Rahnella aquatilis ZF7 is a plant beneficial strain isolated from Sakura tree soil with potential for biocontrol. Here, we present the complete genome sequence of R. aquatilis ZF7, which consists of one 4.49 Mb circular chromosome and a 54-kb plasmid named pRAZF7. Phylogenetic analyses revealed that R. aquatilis ZF7 is much similar to the strains Rahnella sp. Y9602 and R. aquatilis HX2 than others evaluated. In this study, multiple genes encoding functions that likely contribute to plant growth promotion, biocontrol and stress tolerance were identified by comparative genome analyses, including IAA production, phosphate solubilization, antibiotic resistance and formation of Se nanoparticles (SeNPs). In addition, these functions were also confirmed by in vitro experiments. Considering its ability to form SeNPs, strain R. aquatilis ZF7 will contribute to nano-agriculture. Overall, the features of R. aquatilis ZF7 make it a high potential and competitive strain in biocontrol, and the genome data will help further studies on the mechanisms of plant growth promotion and biocontrol.
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Affiliation(s)
- Lifang Yuan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, 100193, China
| | - Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Fei Zheng
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
- College of Horticulture and Landscape Architecture, Tianjin Agricultural University, Tianjin, 300384, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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11
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Li L, Li J, Peng J, Wu W, Guo Y. Identification ofatpDas an optimal reference gene to explore antibiotic resistance and stress tolerance inRahnella aquatilis. J Appl Microbiol 2019; 126:1096-1107. [DOI: 10.1111/jam.14215] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/06/2018] [Accepted: 01/24/2019] [Indexed: 11/28/2022]
Affiliation(s)
- L. Li
- Department of Ecological Science and Engineering College of Resources and Environmental Sciences, China Agricultural University Beijing China
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences Beijing China
| | - J. Li
- Department of Plant Pathology College of Plant Protection, China Agricultural University Beijing China
| | - J. Peng
- Department of Ecological Science and Engineering College of Resources and Environmental Sciences, China Agricultural University Beijing China
| | - W. Wu
- Department of Ecological Science and Engineering College of Resources and Environmental Sciences, China Agricultural University Beijing China
| | - Y. Guo
- Department of Ecological Science and Engineering College of Resources and Environmental Sciences, China Agricultural University Beijing China
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12
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Peng J, Wu D, Liang Y, Li L, Guo Y. Disruption ofacdSgene reduces plant growth promotion activity and maize saline stress resistance byRahnella aquatilisHX2. J Basic Microbiol 2019; 59:402-411. [DOI: 10.1002/jobm.201800510] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/04/2018] [Accepted: 12/16/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Jing Peng
- Department of Ecological Science and Engineering; College of Resources and Environmental Sciences; China Agricultural University; Beijing P. R. China
- Beijing Key Laboratory of Biodiversity and Organic Farming; China Agricultural University; Beijing P. R. China
| | - Di Wu
- Department of Ecological Science and Engineering; College of Resources and Environmental Sciences; China Agricultural University; Beijing P. R. China
- Beijing Key Laboratory of Biodiversity and Organic Farming; China Agricultural University; Beijing P. R. China
| | - Yue Liang
- College of Plant Protection; Shenyang Agricultural University; Shenyang Liaoning P. R. China
| | - Lei Li
- Department of Ecological Science and Engineering; College of Resources and Environmental Sciences; China Agricultural University; Beijing P. R. China
- Beijing Key Laboratory of Biodiversity and Organic Farming; China Agricultural University; Beijing P. R. China
| | - Yanbin Guo
- Department of Ecological Science and Engineering; College of Resources and Environmental Sciences; China Agricultural University; Beijing P. R. China
- Beijing Key Laboratory of Biodiversity and Organic Farming; China Agricultural University; Beijing P. R. China
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13
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Zhang L, Fan J, Feng G, Declerck S. The arbuscular mycorrhizal fungus Rhizophagus irregularis MUCL 43194 induces the gene expression of citrate synthase in the tricarboxylic acid cycle of the phosphate-solubilizing bacterium Rahnella aquatilis HX2. MYCORRHIZA 2019; 29:69-75. [PMID: 30368606 DOI: 10.1007/s00572-018-0871-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/19/2018] [Indexed: 06/08/2023]
Abstract
An increasing number of studies have demonstrated that arbuscular mycorrhizal fungi can cooperate with other soil microorganisms, e.g., bacteria, which develop near or on the surface of the extraradical hyphae where they perform multiple functions. However, the mechanisms involved in this privileged relationship are still poorly known. In the present study, we investigated how the arbuscular mycorrhizal fungus Rhizophagus irregularis MUCL 43194 influences the three pace-making enzymes (i.e., citrate synthase, isocitrate dehydrogenase, and α-oxoglutarate dehydrogenase) of the tricarboxylic acid (TCA) cycle in the phosphate-solubilizing bacterium Rahnella aquatilis HX2. The study was conducted under strict in vitro culture conditions and analysis made at the transcriptional level. Results showed that R. irregularis induced the expression of the gene-encoding citrate synthase (gltA), the pace-making enzyme involved in the first step of the TCA cycle, in R. aquatilis at all time points of observation (i.e., 1, 6, 12, 24, 48, and 72 h). The expression of the gene-encoding isocitrate dehydrogenase (icd) significantly decreased at 6, 12, 24, 48, and 72 h and the expression of the gene-encoding α-oxoglutarate dehydrogenase E1 component (kgdhc) significantly increased at 1, 6, and 48 h. The above results suggested that R. irregularis may influence the level of adenosine triphosphate production in R. aquatilis and thus the metabolism of the bacterium by stimulating the expression of gltA involved in the TCA cycle. Our results suggest a fine-tuned dialog between R. irregularis MUCL 43194 and R. aquatilis HX2 and emphasize the complexity of the interactions that might take place at the hyphal surface of arbuscular mycorrhizal fungi hosting communities of microbes.
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Affiliation(s)
- Lin Zhang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
- Earth and Life Institute, Applied microbiology, Mycology, Université catholique de Louvain, Croix du sud 2, bte L7.05.06, 1348, Louvain-la-Neuve, Belgium
| | - Jiequn Fan
- Shanghai Academy of Agricultural Sciences, Shanghai, 201106, China
| | - Gu Feng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
| | - Stéphane Declerck
- Earth and Life Institute, Applied microbiology, Mycology, Université catholique de Louvain, Croix du sud 2, bte L7.05.06, 1348, Louvain-la-Neuve, Belgium
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14
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Biosynthesis of selenium nanoparticles and effects of selenite, selenate, and selenomethionine on cell growth and morphology in Rahnella aquatilis HX2. Appl Microbiol Biotechnol 2018; 102:6191-6205. [PMID: 29806064 DOI: 10.1007/s00253-018-9060-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 01/13/2023]
Abstract
Rahnella aquatilis HX2 (proteobacteria) shows tolerance to selenium (Se). The minimum inhibitory concentrations of selenomethionine (Se-Met), selenite [Se (IV)], and selenate [Se (VI)] to HX2 are 4.0, 85.0, and 590.0 mM, respectively. HX2 shows the ability to reduce Se (IV) and Se (VI) to elemental Se nanoparticles (SeNPs). The maximum production of SeNPs by HX2 strain is 1.99 and 3.85 mM in Luria-Bertani (LB) broth with 5 mM Se (IV) and 10 mM Se (VI), respectively. The morphology of SeNPs and cells were observed by transmission electron microscope, environmental scanning electron microscope, and selected area electric diffraction detector. Spherical SeNPs with amorphous structure were found in the cytoplasm, membrane, and exterior of cells. Morphological variations of the cell membrane were further confirmed by the release of cellular materials absorbed at 260 nm. Flagella were inhibited and cell sizes were 1.8-, 1.6-, and 1.2-fold increases with the Se-Met, Se (VI), and Se (IV) treatments, respectively. The real-time quantitative PCR analysis indicated that some of the genes controlling Se metabolism or cell morphology, including cysA, cysP, rodA, ZntA, and ada, were significantly upregulated, while grxA, fliO, flgE, and fliC genes were significantly downregulated in those Se treatments. This study provided novel valuable information concerning the cell morphology along with biological synthesis process of SeNPs in R. aquatilis and demonstrated that the strain HX2 could be applied in both biosynthesis of SeNPs and in management of environmental Se pollution.
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15
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Mei L, Xu S, Lu P, Lin H, Guo Y, Wang Y. CsrB, a noncoding regulatory RNA, is required for BarA-dependent expression of biocontrol traits in Rahnella aquatilis HX2. PLoS One 2017; 12:e0187492. [PMID: 29091941 PMCID: PMC5665550 DOI: 10.1371/journal.pone.0187492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 10/21/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Rahnella aquatilis is ubiquitous and its certain strains have the applicative potent as a plant growth-promoting rhizobacteria. R. aquatilis HX2 is a biocontrol agent to produce antibacterial substance (ABS) and showed efficient biocontrol against crown gall caused by Agrobacterium vitis on sunflower and grapevine plants. The regulatory network of the ABS production and biocontrol activity is still limited known. METHODOLOGY/PRINCIPAL FINDINGS In this study, a transposon-mediated mutagenesis strategy was used to investigate the regulators that involved in the biocontrol activity of R. aquatilis HX2. A 366-nt noncoding RNA CsrB was identified in vitro and in vivo, which regulated ABS production and biocontrol activity against crown gall on sunflower plants, respectively. The predicted product of noncoding RNA CsrB contains 14 stem-loop structures and an additional ρ-independent terminator harpin, with 23 characteristic GGA motifs in the loops and other unpaired regions. CsrB is required for ABS production and biocontrol activity in the biocontrol regulation by a two-component regulatory system BarA/UvrY in R. aquatilis HX2. CONCLUSION/SIGNIFICANCE The noncoding RNA CsrB regulates BarA-dependent ABS production and biocontrol activity in R. aquatilis HX2. To the best of our knowledge, this is the first report of noncoding RNA as a regulator for biocontrol function in R. aquatilis.
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Affiliation(s)
- Li Mei
- College of Forestry and Biotechnology, Zhejiang A&F University, Lin’An, China
| | - Sanger Xu
- College of Forestry and Biotechnology, Zhejiang A&F University, Lin’An, China
| | - Peng Lu
- College of Forestry and Biotechnology, Zhejiang A&F University, Lin’An, China
| | - Haiping Lin
- College of Forestry and Biotechnology, Zhejiang A&F University, Lin’An, China
| | - Yanbin Guo
- Department of Ecological Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
| | - Yongjun Wang
- College of Forestry and Biotechnology, Zhejiang A&F University, Lin’An, China
- National and Provincial Joint Engineering Laboratory of Bio-pesticide Preparation, Lin’An, China
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16
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Ludueña LM, Anzuay MS, Magallanes-Noguera C, Tonelli ML, Ibañez FJ, Angelini JG, Fabra A, McIntosh M, Taurian T. Effects of P limitation and molecules from peanut root exudates on pqqE gene expression and pqq promoter activity in the phosphate-solubilizing strain Serratia sp. S119. Res Microbiol 2017; 168:710-721. [PMID: 28709697 DOI: 10.1016/j.resmic.2017.07.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/25/2017] [Accepted: 07/03/2017] [Indexed: 01/23/2023]
Abstract
The mineral phosphate-solubilizing phenotype in bacteria is attributed predominantly to secretion of gluconic acid produced by oxidation of glucose by the glucose dehydrogenase enzyme and its cofactor, pyrroloquinoline quinone. This study analyzes pqqE gene expression and pqq promoter activity in the native phosphate-solubilizing bacterium Serratia sp S119 growing under P-limitation, and in the presence of root exudates obtained from peanut plants, also growing under P-limitation. Results indicated that Serratia sp. S119 contains a pqq operon composed of six genes (pqqA,B,C,D,E,F) and two promoters, one upstream of pqqA and other between pqqA and pqqB. PqqE gene expression and pqq promoter activity increased under P-limiting growth conditions and not under N-deficient conditions. In the plant-bacteria interaction assay, the activity of the bacterial pqq promoter region varied depending on the concentration and type of root exudates and on the bacterial growth phase. Root exudates from peanut plants growing under P-available and P-limiting conditions showed differences in their composition. It is concluded from this study that the response of Serratia sp. S119 to phosphorus limitation involves an increase in expression of pqq genes, and that molecules exuded by peanut roots modify expression of these phosphate-solubilizing bacterial genes during plant-bacteria interactions.
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Affiliation(s)
- Liliana M Ludueña
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Maria S Anzuay
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Cynthia Magallanes-Noguera
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Maria L Tonelli
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Fernando J Ibañez
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Jorge G Angelini
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Adriana Fabra
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
| | - Matthew McIntosh
- Loewe Center for Synthetic Microbiology, Philipps-University Marburg, Hans-Meerwein-Str. 6, 35043 Marburg, Germany.
| | - Tania Taurian
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal 3, 5800 Rio Cuarto, Córdoba, Argentina.
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17
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Briones-Roblero CI, Hernández-García JA, Gonzalez-Escobedo R, Soto-Robles LV, Rivera-Orduña FN, Zúñiga G. Structure and dynamics of the gut bacterial microbiota of the bark beetle, Dendroctonus rhizophagus (Curculionidae: Scolytinae) across their life stages. PLoS One 2017; 12:e0175470. [PMID: 28406998 PMCID: PMC5391025 DOI: 10.1371/journal.pone.0175470] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/27/2017] [Indexed: 11/18/2022] Open
Abstract
Bark beetles play an important role as agents of natural renovation and regeneration in coniferous forests. Several studies have documented the metabolic capacity of bacteria associated with the gut, body surface, and oral secretions of these insects; however, little is known about how the bacterial community structure changes during the life cycle of the beetles. This study represents the first comprehensive analysis of the bacterial community of the gut of the bark beetle D. rhizophagus during the insect’s life cycle using 454 pyrosequencing. A total of 4 bacterial phyla, 7 classes, 15 families and 23 genera were identified. The α-diversity was low, as demonstrated in previous studies. The dominant bacterial taxa belonged to the Enterobacteriaceae and Pseudomonadaceae families. This low α-diversity can be attributed to the presence of defensive chemical compounds in conifers or due to different morpho-physiological factors in the gut of these insects acting as strong selective factors. Members of the genera Rahnella, Serratia, Pseudomonas and Propionibacterium were found at all life stages, and the first three genera, particularly Rahnella, were predominant suggesting the presence of a core microbiome in the gut. Significant differences in β-diversity were observed, mainly due to bacterial taxa present at low frequencies and only in certain life stages. The predictive functional profiling indicated metabolic pathways related to metabolism of amino acids and carbohydrates, and membrane transport as the most significant in the community. These differences in the community structure might be due to several selective factors, such as gut compartmentalization, physicochemical conditions, and microbial interactions.
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Affiliation(s)
- Carlos Iván Briones-Roblero
- Posgrado en Ciencias Quimicobiológicas, Instituto Politécnico Nacional, Ciudad de México, México
- Departamento de Zoología, Instituto Politécnico Nacional, Ciudad de México, México
| | - Juan Alfredo Hernández-García
- Posgrado en Ciencias Quimicobiológicas, Instituto Politécnico Nacional, Ciudad de México, México
- Departamento de Zoología, Instituto Politécnico Nacional, Ciudad de México, México
| | - Roman Gonzalez-Escobedo
- Posgrado en Ciencias Quimicobiológicas, Instituto Politécnico Nacional, Ciudad de México, México
- Departamento de Zoología, Instituto Politécnico Nacional, Ciudad de México, México
| | - L. Viridiana Soto-Robles
- Posgrado en Ciencias Quimicobiológicas, Instituto Politécnico Nacional, Ciudad de México, México
- Departamento de Zoología, Instituto Politécnico Nacional, Ciudad de México, México
| | - Flor N. Rivera-Orduña
- Departamento de Microbiología, Instituto Politécnico Nacional, Ciudad de México, México
| | - Gerardo Zúñiga
- Departamento de Zoología, Instituto Politécnico Nacional, Ciudad de México, México
- * E-mail:
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Ludueña LM, Anzuay MS, Angelini JG, Barros G, Luna MF, Monge MDP, Fabra A, Taurian T. Role of bacterial pyrroloquinoline quinone in phosphate solubilizing ability and in plant growth promotion on strain Serratia sp. S119. Symbiosis 2016. [DOI: 10.1007/s13199-016-0434-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Li L, Jiao Z, Hale L, Wu W, Guo Y. Disruption of gene pqqA or pqqB reduces plant growth promotion activity and biocontrol of crown gall disease by Rahnella aquatilis HX2. PLoS One 2014; 9:e115010. [PMID: 25502691 PMCID: PMC4263746 DOI: 10.1371/journal.pone.0115010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/17/2014] [Indexed: 11/18/2022] Open
Abstract
Rahnella aquatilis strain HX2 has the ability to promote maize growth and suppress sunflower crown gall disease caused by Agrobacterium vitis, A. tumefaciens, and A. rhizogenes. Pyrroloquinoline quinone (PQQ), a cofactor of aldose and alcohol dehydrogenases, is required for the synthesis of an antibacterial substance, gluconic acid, by HX2. Mutants of HX2 unable to produce PQQ were obtained by in-frame deletion of either the pqqA or pqqB gene. In this study, we report the independent functions of pqqA and pqqB genes in relation to PQQ synthesis. Interestingly, both the pqqA and pqqB mutants of R. aquatilis eliminated the ability of strain HX2 to produce antibacterial substance, which in turn, reduced the effectiveness of the strain for biological control of sunflower crown gall disease. The mutation also resulted in decreased mineral phosphate solubilization by HX2, which reduced the efficacy of this strain as a biological fertilizer. These functions were restored by complementation with the wild-type pqq gene cluster. Additionally, the phenotypes of HX2 derivatives, including colony morphology, growth dynamic, and pH change of culture medium were impacted to different extents. Our findings suggested that pqqA and pqqB genes individually play important functions in PQQ biosynthesis and are required for antibacterial activity and phosphorous solubilization. These traits are essential for R. aquatilis efficacy as a biological control and plant growth promoting strain. This study enhances our fundamental understanding of the biosynthesis of an environmentally significant cofactor produced by a promising biocontrol and biological fertilizer strain.
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Affiliation(s)
- Lei Li
- Department of Ecological Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China
| | - Ziwei Jiao
- College of Chemistry and Biological Sciences, Yi Li Normal University, Yining, Xinjiang, China
| | - Lauren Hale
- Department of Environmental Sciences, University of California Riverside, Riverside, California, United States of America
| | - Wenliang Wu
- Department of Ecological Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China
| | - Yanbin Guo
- Department of Ecological Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China
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20
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Xu J, Deng P, Showmaker KC, Wang H, Baird SM, Lu SE. The pqqC gene is essential for antifungal activity of Pseudomonas kilonensis JX22 against Fusarium oxysporum f. sp. lycopersici. FEMS Microbiol Lett 2014; 353:98-105. [PMID: 24588744 DOI: 10.1111/1574-6968.12411] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/13/2014] [Accepted: 02/25/2014] [Indexed: 11/29/2022] Open
Abstract
Strain JX22, exhibiting a broad range of antimicrobial activities to fungal pathogens, was isolated and classified as representing Pseudomonas kilonensis. In this study, the mutant JX22MT1 was obtained by the EZ-Tn5 transposon mutation and showed no antifungal activity against Fusarium oxysporum f. sp. lycopersici as compared with wild-type strain JX22. The pqqC gene was disrupted in the mutant. Antifungal activity at the wild-type level was restored from the mutant JX22MT1 with the introduction of the functional pqqC gene, which encodes pyrroloquinoline-quinone synthesis protein C. The results suggest that pqqC is essential for antifungal activity of P. kilonensis JX22 against F. oxysporum f. sp. lycopersici.
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Affiliation(s)
- Jianhong Xu
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture/Jiangsu Academy of Agricultural Sciences, Nanjing, China; Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, USA
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21
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Ge X, Wang W, Du B, Wang J, Xiong X, Zhang W. Multiple pqqA genes respond differently to environment and one contributes dominantly to pyrroloquinoline quinone synthesis. J Basic Microbiol 2013; 55:312-23. [PMID: 23828377 DOI: 10.1002/jobm.201300037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 06/01/2013] [Indexed: 11/11/2022]
Abstract
Pyrroloquinoline quinone is the third redox cofactor after nicotinamide and flavin in bacteria, and its biosynthesis pathway comprise five steps initiated from a precursor peptide PqqA coded by pqqA gene. Methylovorus sp. MP688 is equipped with five copies of pqqA genes. Herein, the transcription of pqqA genes under different conditions by real-time quantitative PCR and β-galactosidase reporter genes are reported. Multiple pqqA genes were proved to play significant roles and contribute differently in PQQ synthesis. pqqA1, pqqA2, and pqqA4 were determined to be dominantly transcribed over the others, and correspondingly absence of any of the three genes caused a decrease in PQQ synthesis. Notably, pqqA was up-regulated in low pH and limited oxygen environment, and it is pqqA2 promoter that could be induced when bacteria were transferred from pH 7.0 to pH 5.5. Deletion analysis revealed a region within pqqA2 promoter inhibiting transcription. PQQ concentration was increased by overexpression of pqq genes under control of truncated pqqA2 promoter. The results not only imply there exist negative transcriptional regulators for pqqA2 but also provide us a new approach to achieve higher PQQ production by deleting the target binding sequence.
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Affiliation(s)
- Xin Ge
- Laboratory of Microorganism Engineering, Beijing Institute of Biotechnology, Beijing, China
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22
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Kremmydas GF, Tampakaki AP, Georgakopoulos DG. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose. PLoS One 2013; 8:e61808. [PMID: 23596526 PMCID: PMC3626644 DOI: 10.1371/journal.pone.0061808] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 03/18/2013] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ), and two genes (sup5 and sup6) which seem to be organized in a putative operon. This operon (named supX) consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.
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Affiliation(s)
- Gerasimos F. Kremmydas
- Department of Agricultural Biotechnology, Agricultural University of Athens, Athens, Greece
| | - Anastasia P. Tampakaki
- Department of Agricultural Biotechnology, Agricultural University of Athens, Athens, Greece
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Guo Y, Jiao Z, Li L, Wu D, Crowley DE, Wang Y, Wu W. Draft genome sequence of Rahnella aquatilis strain HX2, a plant growth-promoting rhizobacterium isolated from vineyard soil in Beijing, China. J Bacteriol 2012; 194:6646-7. [PMID: 23144397 PMCID: PMC3497517 DOI: 10.1128/jb.01769-12] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 09/25/2012] [Indexed: 11/20/2022] Open
Abstract
Rahnella aquatilis strain HX2 is a plant growth-promoting, disease-suppressive rhizobacterium that was isolated from a vineyard soil in Beijing, China. Here, we report the genome sequence of this strain, which provides a valuable resource for future research examining the mechanisms of traits associated with plant growth promotion and biocontrol.
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Affiliation(s)
- Yanbin Guo
- Department of Ecology and Ecological Engineering, College of Resources and Environmental Science, China Agricultural University, Beijing, People's Republic of China
| | - Ziwei Jiao
- Department of Ecology and Ecological Engineering, College of Resources and Environmental Science, China Agricultural University, Beijing, People's Republic of China
| | - Lei Li
- Department of Ecology and Ecological Engineering, College of Resources and Environmental Science, China Agricultural University, Beijing, People's Republic of China
| | - Di Wu
- Department of Ecology and Ecological Engineering, College of Resources and Environmental Science, China Agricultural University, Beijing, People's Republic of China
| | - David E. Crowley
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - Yongjun Wang
- Key Laboratory of Forest Protection, College of Forestry and Biotechnology, Zhejiang Agricultural and Forestry University, Lin'an, People's Republic of China
| | - Wenliang Wu
- Department of Ecology and Ecological Engineering, College of Resources and Environmental Science, China Agricultural University, Beijing, People's Republic of China
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Rajpurohit YS, Desai SS, Misra HS. Pyrroloquinoline quinone and a quinoprotein kinase support γ-radiation resistance inDeinococcus radioduransand regulate gene expression. J Basic Microbiol 2012; 53:518-31. [DOI: 10.1002/jobm.201100650] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 04/02/2012] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Hari Sharan Misra
- Molecular Biology Division; Bhabha Atomic Research Centre; Mumbai; India
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26
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Shen YQ, Bonnot F, Imsand EM, RoseFigura JM, Sjölander K, Klinman JP. Distribution and properties of the genes encoding the biosynthesis of the bacterial cofactor, pyrroloquinoline quinone. Biochemistry 2012; 51:2265-75. [PMID: 22324760 DOI: 10.1021/bi201763d] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Pyrroloquinoline quinone (PQQ) is a small, redox active molecule that serves as a cofactor for several bacterial dehydrogenases, introducing pathways for carbon utilization that confer a growth advantage. Early studies had implicated a ribosomally translated peptide as the substrate for PQQ production. This study presents a sequence- and structure-based analysis of the components of the pqq operon. We find the necessary components for PQQ production are present in 126 prokaryotes, most of which are Gram-negative and a number of which are pathogens. A total of five gene products, PqqA, PqqB, PqqC, PqqD, and PqqE, are identified as being obligatory for PQQ production. Three of the gene products in the pqq operon, PqqB, PqqC, and PqqE, are members of large protein superfamilies. By combining evolutionary conservation patterns with information from three-dimensional structures, we are able to differentiate the gene products involved in PQQ biosynthesis from those with divergent functions. The observed persistence of a conserved gene order within analyzed operons strongly suggests a role for protein-protein interactions in the course of cofactor biosynthesis. These studies propose previously unidentified roles for several of the gene products, as well as identifying possible new targets for antibiotic design and application.
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Affiliation(s)
- Yao-Qing Shen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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Pyrroloquinoline quinone biosynthesis gene pqqC, a novel molecular marker for studying the phylogeny and diversity of phosphate-solubilizing pseudomonads. Appl Environ Microbiol 2011; 77:7345-54. [PMID: 21856827 DOI: 10.1128/aem.05434-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many root-colonizing pseudomonads are able to promote plant growth by increasing phosphate availability in soil through solubilization of poorly soluble rock phosphates. The major mechanism of phosphate solubilization by pseudomonads is the secretion of gluconic acid, which requires the enzyme glucose dehydrogenase and its cofactor pyrroloquinoline quinone (PQQ). The main aim of this study was to evaluate whether a PQQ biosynthetic gene is suitable to study the phylogeny of phosphate-solubilizing pseudomonads. To this end, two new primers, which specifically amplify the pqqC gene of the Pseudomonas genus, were designed. pqqC fragments were amplified and sequenced from a Pseudomonas strain collection and from a natural wheat rhizosphere population using cultivation-dependent and cultivation-independent approaches. Phylogenetic trees based on pqqC sequences were compared to trees obtained with the two concatenated housekeeping genes rpoD and gyrB. For both pqqC and rpoD-gyrB, similar main phylogenetic clusters were found. However, in the pqqC but not in the rpoD-gyrB tree, the group of fluorescent pseudomonads producing the antifungal compounds 2,4-diacetylphloroglucinol and pyoluteorin was located outside the Pseudomonas fluorescens group. pqqC sequences from isolated pseudomonads were differently distributed among the identified phylogenetic groups than pqqC sequences derived from the cultivation-independent approach. Comparing pqqC phylogeny and phosphate solubilization activity, we identified one phylogenetic group with high solubilization activity. In summary, we demonstrate that the gene pqqC is a novel molecular marker that can be used complementary to housekeeping genes for studying the diversity and evolution of plant-beneficial pseudomonads.
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A novel antifungal Pseudomonas fluorescens isolated from potato soils in Greenland. Curr Microbiol 2010; 62:1185-92. [PMID: 21165740 DOI: 10.1007/s00284-010-9846-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
Abstract
A rhizobacterium with high antifungal activity was isolated from a potato field at Inneruulalik, South Greenland. Phylogenetic analysis based on multi locus sequence typing showed that the bacterium was affiliated with strains of Pseudomonas fluorescens. The bacterium, denoted as Pseudomonas fluorescens In5, inhibited in vitro a broad range of phytopathogenic fungi, and the antifungal activity increased with decreasing temperature. Microcosm experiments demonstrated that P. fluorescens In5 protected tomato seedlings from Rhizoctonia solani. Transposon mutagenesis showed that the major cause for the antifungal activity of P. fluorescens In5 was a novel non-ribosomal peptide synthase (NRPS) gene. In addition, transposon mutagenesis showed that P. fluorescens In5 also contained a putative quinoprotein glucose dehydrogenase gene, which was involved in growth inhibition of phytopathogenic fungi. Although P. fluorescens In5 contained the capacity to synthesize hydrogen cyanide, β-1,3-glucanase, protease, and chitinase, these did not seem to play a role in the in vitro and microcosm antifungal assays.
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