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Etesami H, Glick BR. Bacterial indole-3-acetic acid: A key regulator for plant growth, plant-microbe interactions, and agricultural adaptive resilience. Microbiol Res 2024; 281:127602. [PMID: 38228017 DOI: 10.1016/j.micres.2024.127602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/18/2024]
Abstract
Indole-3-acetic acid (IAA), a fundamental phytohormone categorized under auxins, not only influences plant growth and development but also plays a critical role in plant-microbe interactions. This study reviews the role of IAA in bacteria-plant communication, with a focus on its biosynthesis, regulation, and the subsequent effects on host plants. Bacteria synthesize IAA through multiple pathways, which include the indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), and several other routes, whose full mechanisms remain to be fully elucidated. The production of bacterial IAA affects root architecture, nutrient uptake, and resistance to various abiotic stresses such as drought, salinity, and heavy metal toxicity, enhancing plant resilience and thus offering promising routes to sustainable agriculture. Bacterial IAA synthesis is regulated through complex gene networks responsive to environmental cues, impacting plant hormonal balances and symbiotic relationships. Pathogenic bacteria have adapted mechanisms to manipulate the host's IAA dynamics, influencing disease outcomes. On the other hand, beneficial bacteria utilize IAA to promote plant growth and mitigate abiotic stresses, thereby enhancing nutrient use efficiency and reducing dependency on chemical fertilizers. Advancements in analytical methods, such as liquid chromatography-tandem mass spectrometry, have improved the quantification of bacterial IAA, enabling accurate measurement and analysis. Future research focusing on molecular interactions between IAA-producing bacteria and host plants could facilitate the development of biotechnological applications that integrate beneficial bacteria to improve crop performance, which is essential for addressing the challenges posed by climate change and ensuring global food security. This integration of bacterial IAA producers into agricultural practice promises to revolutionize crop management strategies by enhancing growth, fostering resilience, and reducing environmental impact.
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Affiliation(s)
- Hassan Etesami
- Soil Science Department, University of Tehran, Tehran, Iran.
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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2
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McTavish KJ, Almeida RND, Tersigni J, Raimundi MK, Gong Y, Wang PW, Gontijo GF, de Souza RM, de Resende MLV, Desveaux D, Guttman DS. Pseudomonas syringae coffee blight is associated with the horizontal transfer of plasmid-encoded type III effectors. THE NEW PHYTOLOGIST 2024; 241:409-429. [PMID: 37953378 DOI: 10.1111/nph.19364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 09/29/2023] [Indexed: 11/14/2023]
Abstract
The emergence of new pathogens is an ongoing threat to human health and agriculture. While zoonotic spillovers received considerable attention, the emergence of crop diseases is less well studied. Here, we identify genomic factors associated with the emergence of Pseudomonas syringae bacterial blight of coffee. Fifty-three P. syringae strains from diseased Brazilian coffee plants were sequenced. Comparative and evolutionary analyses were used to identify loci associated with coffee blight. Growth and symptomology assays were performed to validate the findings. Coffee isolates clustered in three lineages, including primary phylogroups PG3 and PG4, and secondary phylogroup PG11. Genome-wide association study of the primary PG strains identified 37 loci, including five effectors, most of which were encoded on a plasmid unique to the PG3 and PG4 coffee strains. Evolutionary analyses support the emergence of coffee blight in PG4 when the coffee-associated plasmid and associated effectors derived from a divergent plasmid carried by strains associated with other hosts. This plasmid was only recently transferred into PG3. Natural diversity and CRISPR-Cas9 plasmid curing were used to show that strains with the coffee-associated plasmid grow to higher densities and cause more severe disease symptoms in coffee. This work identifies possible evolutionary mechanisms underlying the emergence of a new lineage of coffee pathogens.
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Affiliation(s)
- Kathryn J McTavish
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
| | - Renan N D Almeida
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
| | - Jonathan Tersigni
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
| | - Melina K Raimundi
- Department of Phytopathology, Universidade Federal de Lavras, Lavras, MG, CEP 37200-000, Brazil
| | - Yunchen Gong
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M6S 2Y1, Canada
| | - Pauline W Wang
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M6S 2Y1, Canada
| | - Guilherme F Gontijo
- Department of Phytopathology, Universidade Federal de Lavras, Lavras, MG, CEP 37200-000, Brazil
| | - Ricardo M de Souza
- Department of Phytopathology, Universidade Federal de Lavras, Lavras, MG, CEP 37200-000, Brazil
| | - Mario L V de Resende
- Department of Phytopathology, Universidade Federal de Lavras, Lavras, MG, CEP 37200-000, Brazil
| | - Darrell Desveaux
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M6S 2Y1, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M6S 2Y1, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, ON, M6S 2Y1, Canada
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Shetty S, Kamble A, Singh H. Insights into the Potential Role of Plasmids in the Versatility of the Genus Pantoea. Mol Biotechnol 2023:10.1007/s12033-023-00960-3. [PMID: 38007817 DOI: 10.1007/s12033-023-00960-3] [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: 06/16/2023] [Accepted: 10/23/2023] [Indexed: 11/28/2023]
Abstract
In the past two decades, 25 different species of the genus Pantoea within the Enterobacteriaceae family, have been isolated from different environmental niches. These species have a wide range of biological roles. Versatility in functions and hosts indicate that this genus has undergone extensive genetic diversification, which can be attributed to the different extra-chromosomal genetic elements or plasmids found across this genus. We have analyzed the functions of these plasmids and categorized them into four major groups for a better understanding of their future applications. The first and second group includes plasmids that contribute to genetic diversification and pathogenicity, respectively. The third group comprises cryptic plasmids of Pantoea. The last group includes plasmids that play a role in the metabolic versatility of the genus Pantoea. We have analyzed the data available up to May 2023 from two databases (viz; NCBI and PLSDB). In our analysis we have found a vast gap in knowledge. Complete gene annotations are available for only a few of the plasmids. This review highlights these challenges as an avenue for future research.
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Affiliation(s)
- Srinidhi Shetty
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Mumbai, 400056, India
| | - Asmita Kamble
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Mumbai, 400056, India
| | - Harinder Singh
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS Deemed to be University, Mumbai, 400056, India.
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4
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Geraffi N, Gupta P, Wagner N, Barash I, Pupko T, Sessa G. Comparative sequence analysis of pPATH pathogenicity plasmids in Pantoea agglomerans gall-forming bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1198160. [PMID: 37583594 PMCID: PMC10425158 DOI: 10.3389/fpls.2023.1198160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/10/2023] [Indexed: 08/17/2023]
Abstract
Acquisition of the pathogenicity plasmid pPATH that encodes a type III secretion system (T3SS) and effectors (T3Es) has likely led to the transition of a non-pathogenic bacterium into the tumorigenic pathogen Pantoea agglomerans. P. agglomerans pv. gypsophilae (Pag) forms galls on gypsophila (Gypsophila paniculata) and triggers immunity on sugar beet (Beta vulgaris), while P. agglomerans pv. betae (Pab) causes galls on both gypsophila and sugar beet. Draft sequences of the Pag and Pab genomes were previously generated using the MiSeq Illumina technology and used to determine partial T3E inventories of Pab and Pag. Here, we fully assembled the Pab and Pag genomes following sequencing with PacBio technology and carried out a comparative sequence analysis of the Pab and Pag pathogenicity plasmids pPATHpag and pPATHpab. Assembly of Pab and Pag genomes revealed a ~4 Mbp chromosome with a 55% GC content, and three and four plasmids in Pab and Pag, respectively. pPATHpag and pPATHpab share 97% identity within a 74% coverage, and a similar GC content (51%); they are ~156 kb and ~131 kb in size and consist of 198 and 155 coding sequences (CDSs), respectively. In both plasmids, we confirmed the presence of highly similar gene clusters encoding a T3SS, as well as auxin and cytokinins biosynthetic enzymes. Three putative novel T3Es were identified in Pab and one in Pag. Among T3SS-associated proteins encoded by Pag and Pab, we identified two novel chaperons of the ShcV and CesT families that are present in both pathovars with high similarity. We also identified insertion sequences (ISs) and transposons (Tns) that may have contributed to the evolution of the two pathovars. These include seven shared IS elements, and three ISs and two transposons unique to Pab. Finally, comparative sequence analysis revealed plasmid regions and CDSs that are present only in pPATHpab or in pPATHpag. The high similarity and common features of the pPATH plasmids support the hypothesis that the two strains recently evolved into host-specific pathogens.
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Affiliation(s)
- Naama Geraffi
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Priya Gupta
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Isaac Barash
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Guido Sessa
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Rocha RT, de Almeida FM, Pappas MCR, Pappas GJ, Martins K. Complete Genome Sequence of Pantoea stewartii RON18713 from Brazil Nut Tree Phyllosphere Reveals Genes Involved in Plant Growth Promotion. Microorganisms 2023; 11:1729. [PMID: 37512901 PMCID: PMC10383142 DOI: 10.3390/microorganisms11071729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/09/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
The Amazonian rainforest is a hyper-diverse ecosystem in the number of species and the myriad of intertaxon relationships that are mostly understudied. In order to characterize a dominant and economically important Amazonian species, the Brazil nut tree (Bertholletia excelsa Bonpl.), at the genome level, wegenerated high-coverage long-read sequencing data from the leaves of a single individual. The genome assembly revealed an unexpected discovery: two circular contigs that could be assigned to the chromosome and a plasmid of a Pantoea stewartii strain. Comparative genomics revealed that this strain belongs to the indologenes subspecies and displays high synteny with other strains isolated from diseased leaves of the neotropical palm Bactris gasipaes Kunth. Investigation of pathogenicity-related genes revealed the absence of the entire type III secretion system gene cluster in the plasmid, which was otherwise highly similar to a plasmid from an isolate known to cause disease in Dracaena sanderiana Mast. In contrast, several genes associated with plant-growth promoting traits were detected, including genes involved in indole-3-acetic acid (IAA) production, phosphate solubilization, and biosynthesis of siderophores. In summary, we report the genome of an uncultivated P. stewartii subsp. indologenes strain associated with the Brazil nut tree and potentially a plant growth-promoting bacteria.
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Affiliation(s)
| | | | - Marília C R Pappas
- EMBRAPA Genetic Resources and Biotechnology, Brasília 70770-917, DF, Brazil
| | | | - Karina Martins
- Department of Biology, Federal University of São Carlos, Sorocaba 18052-780, SP, Brazil
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Fiutek N, Couger MB, Pirro S, Roy SW, de la Torre JR, Connor EF. Genomic Assessment of the Contribution of the Wolbachia Endosymbiont of Eurosta solidaginis to Gall Induction. Int J Mol Sci 2023; 24:ijms24119613. [PMID: 37298563 DOI: 10.3390/ijms24119613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/25/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
We explored the genome of the Wolbachia strain, wEsol, symbiotic with the plant-gall-inducing fly Eurosta solidaginis with the goal of determining if wEsol contributes to gall induction by its insect host. Gall induction by insects has been hypothesized to involve the secretion of the phytohormones cytokinin and auxin and/or proteinaceous effectors to stimulate cell division and growth in the host plant. We sequenced the metagenome of E. solidaginis and wEsol and assembled and annotated the genome of wEsol. The wEsol genome has an assembled length of 1.66 Mbp and contains 1878 protein-coding genes. The wEsol genome is replete with proteins encoded by mobile genetic elements and shows evidence of seven different prophages. We also detected evidence of multiple small insertions of wEsol genes into the genome of the host insect. Our characterization of the genome of wEsol indicates that it is compromised in the synthesis of dimethylallyl pyrophosphate (DMAPP) and S-adenosyl L-methionine (SAM), which are precursors required for the synthesis of cytokinins and methylthiolated cytokinins. wEsol is also incapable of synthesizing tryptophan, and its genome contains no enzymes in any of the known pathways for the synthesis of indole-3-acetic acid (IAA) from tryptophan. wEsol must steal DMAPP and L-methionine from its host and therefore is unlikely to provide cytokinin and auxin to its insect host for use in gall induction. Furthermore, in spite of its large repertoire of predicted Type IV secreted effector proteins, these effectors are more likely to contribute to the acquisition of nutrients and the manipulation of the host's cellular environment to contribute to growth and reproduction of wEsol than to aid E. solidaginis in manipulating its host plant. Combined with earlier work that shows that wEsol is absent from the salivary glands of E. solidaginis, our results suggest that wEsol does not contribute to gall induction by its host.
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Affiliation(s)
- Natalie Fiutek
- Department of Biology, San Francisco State University, San Francisco, CA 94112, USA
| | - Matthew B Couger
- Department of Thoracic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Stacy Pirro
- Iridian Genomes Inc., Bethesda, MD 20817, USA
| | - Scott W Roy
- Department of Biology, San Francisco State University, San Francisco, CA 94112, USA
| | - José R de la Torre
- Department of Biology, San Francisco State University, San Francisco, CA 94112, USA
| | - Edward F Connor
- Department of Biology, San Francisco State University, San Francisco, CA 94112, USA
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7
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Seng S, Ponce GE, Andreas P, Kisiala A, De Clerck-Floate R, Miller DG, Chen MS, Price PW, Tooker JF, Emery RJN, Connor EF. Abscisic Acid: A Potential Secreted Effector Synthesized by Phytophagous Insects for Host-Plant Manipulation. INSECTS 2023; 14:489. [PMID: 37367305 DOI: 10.3390/insects14060489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/18/2023] [Accepted: 05/18/2023] [Indexed: 06/28/2023]
Abstract
Abscisic acid (ABA) is an isoprenoid-derived plant signaling molecule involved in a wide variety of plant processes, including facets of growth and development as well as responses to abiotic and biotic stress. ABA had previously been reported in a wide variety of animals, including insects and humans. We used high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-(ESI)-MS/MS) to examine concentrations of ABA in 17 species of phytophagous insects, including gall- and non-gall-inducing species from all insect orders with species known to induce plant galls: Thysanoptera, Hemiptera, Lepidoptera, Coleoptera, Diptera, and Hymenoptera. We found ABA in insect species in all six orders, in both gall-inducing and non-gall-inducing species, with no tendency for gall-inducing insects to have higher concentrations. The concentrations of ABA in insects often markedly exceeded those typically found in plants, suggesting it is highly improbable that insects obtain all their ABA from their host plant via consumption and sequestration. As a follow-up, we used immunohistochemistry to determine that ABA localizes to the salivary glands in the larvae of the gall-inducing Eurosta solidaginis (Diptera: Tephritidae). The high concentrations of ABA, combined with its localization to salivary glands, suggest that insects are synthesizing and secreting ABA to manipulate their host plants. The pervasiveness of ABA among both gall- and non-gall-inducing insects and our current knowledge of the role of ABA in plant processes suggest that insects are using ABA to manipulate source-sink mechanisms of nutrient allocation or to suppress host-plant defenses. ABA joins the triumvirate of phytohormones, along with cytokinins (CKs) and indole-3-acetic acid (IAA), that are abundant, widespread, and localized to glandular organs in insects and used to manipulate host plants.
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Affiliation(s)
- Stephannie Seng
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Gabriela E Ponce
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Peter Andreas
- Department of Biology, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Anna Kisiala
- Department of Biology, Trent University, Peterborough, ON K9J 7B8, Canada
| | | | - Donald G Miller
- Department of Biological Sciences, California State University, Chico, CA 95929, USA
| | - Ming-Shun Chen
- USDA-ARS and Department of Entomology, Kansas State University, Manhattan, KS 66506, USA
| | - Peter W Price
- Department of Ecology and Evolutionary Biology, Northern Arizona University, Flagstaff, AZ 86001, USA
| | - John F Tooker
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | - R J Neil Emery
- Department of Biology, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Edward F Connor
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
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Sulja A, Pothier JF, Blom J, Moretti C, Buonaurio R, Rezzonico F, Smits THM. Comparative genomics to examine the endophytic potential of Pantoea agglomerans DAPP-PG 734. BMC Genomics 2022; 23:742. [DOI: 10.1186/s12864-022-08966-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/25/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractPantoea agglomerans DAPP-PG 734 was isolated as endophyte from knots (tumors) caused by Pseudomonas savastanoi pv. savastanoi DAPP-PG 722 in olive trees. To understand the plant pathogen-endophyte interaction on a genomic level, the whole genome of P. agglomerans DAPP-PG 734 was sequenced and annotated. The complete genome had a total size of 5′396′424 bp, containing one circular chromosome and four large circular plasmids. The aim of this study was to identify genomic features that could play a potential role in the interaction between P. agglomerans DAPP-PG 734 and P. savastanoi pv. savastanoi DAPP-PG 722. For this purpose, a comparative genomic analysis between the genome of P. agglomerans DAPP-PG 734 and those of related Pantoea spp. was carried out. In P. agglomerans DAPP-PG 734, gene clusters for the synthesis of the Hrp-1 type III secretion system (T3SS), type VI secretion systems (T6SS) and autoinducer, which could play an important role in a plant-pathogenic community enhancing knot formation in olive trees, were identified. Additional gene clusters for the biosynthesis of two different antibiotics, namely dapdiamide E and antibiotic B025670, which were found in regions between integrative conjugative elements (ICE), were observed. The in-depth analysis of the whole genome suggested a characterization of the P. agglomerans DAPP-PG 734 isolate as endophytic bacterium with biocontrol activity rather than as a plant pathogen.
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Carobbi A, Di Nepi S, Fridman CM, Dar Y, Ben‐Yaakov R, Barash I, Salomon D, Sessa G. An antibacterial T6SS in Pantoea agglomerans pv. betae delivers a lysozyme-like effector to antagonize competitors. Environ Microbiol 2022; 24:4787-4802. [PMID: 35706135 PMCID: PMC9796082 DOI: 10.1111/1462-2920.16100] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 06/10/2022] [Indexed: 12/30/2022]
Abstract
The type VI secretion system (T6SS) is deployed by numerous Gram-negative bacteria to deliver toxic effectors into neighbouring cells. The genome of Pantoea agglomerans pv. betae (Pab) phytopathogenic bacteria contains a gene cluster (T6SS1) predicted to encode a complete T6SS. Using secretion and competition assays, we found that T6SS1 in Pab is a functional antibacterial system that allows this pathogen to outcompete rival plant-associated bacteria found in its natural environment. Computational analysis of the T6SS1 gene cluster revealed that antibacterial effector and immunity proteins are encoded within three genomic islands that also harbour arrays of orphan immunity genes or toxin and immunity cassettes. Functional analyses indicated that VgrG, a specialized antibacterial effector, contains a C-terminal catalytically active glucosaminidase domain that is used to degrade prey peptidoglycan. Moreover, we confirmed that a bicistronic unit at the end of the T6SS1 cluster encodes a novel antibacterial T6SS effector and immunity pair. Together, these results demonstrate that Pab T6SS1 is an antibacterial system delivering a lysozyme-like effector to eliminate competitors, and indicate that this bacterium contains additional novel T6SS effectors.
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Affiliation(s)
- Andrea Carobbi
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv
| | - Simone Di Nepi
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv
| | - Chaya M. Fridman
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel Aviv UniversityTel Aviv
| | - Yasmin Dar
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel Aviv UniversityTel Aviv
| | - Rotem Ben‐Yaakov
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel Aviv UniversityTel Aviv
| | - Isaac Barash
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv
| | - Dor Salomon
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel Aviv UniversityTel Aviv
| | - Guido Sessa
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv
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10
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Bellés-Sancho P, Liu Y, Heiniger B, von Salis E, Eberl L, Ahrens CH, Zamboni N, Bailly A, Pessi G. A novel function of the key nitrogen-fixation activator NifA in beta-rhizobia: Repression of bacterial auxin synthesis during symbiosis. FRONTIERS IN PLANT SCIENCE 2022; 13:991548. [PMID: 36247538 PMCID: PMC9554594 DOI: 10.3389/fpls.2022.991548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/31/2022] [Indexed: 06/16/2023]
Abstract
Rhizobia fix nitrogen within root nodules of host plants where nitrogenase expression is strictly controlled by its key regulator NifA. We recently discovered that in nodules infected by the beta-rhizobial strain Paraburkholderia phymatum STM815, NifA controls expression of two bacterial auxin synthesis genes. Both the iaaM and iaaH transcripts, as well as the metabolites indole-acetamide (IAM) and indole-3-acetic acid (IAA) showed increased abundance in nodules occupied by a nifA mutant compared to wild-type nodules. Here, we document the structural changes that a P. phymatum nifA mutant induces in common bean (Phaseolus vulgaris) nodules, eventually leading to hypernodulation. To investigate the role of the P. phymatum iaaMH genes during symbiosis, we monitored their expression in presence and absence of NifA over different stages of the symbiosis. The iaaMH genes were found to be under negative control of NifA in all symbiotic stages. While a P. phymatum iaaMH mutant produced the same number of nodules and nitrogenase activity as the wild-type strain, the nifA mutant produced more nodules than the wild-type that clustered into regularly-patterned root zones. Mutation of the iaaMH genes in a nifA mutant background reduced the presence of these nodule clusters on the root. We further show that the P. phymatum iaaMH genes are located in a region of the symbiotic plasmid with a significantly lower GC content and exhibit high similarity to two genes of the IAM pathway often used by bacterial phytopathogens to deploy IAA as a virulence factor. Overall, our data suggest that the increased abundance of rhizobial auxin in the non-fixing nifA mutant strain enables greater root infection rates and a role for bacterial auxin production in the control of early stage symbiotic interactions.
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Affiliation(s)
- Paula Bellés-Sancho
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Yilei Liu
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Benjamin Heiniger
- Agroscope, Molecular Ecology and Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Elia von Salis
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Christian H. Ahrens
- Agroscope, Molecular Ecology and Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - Nicola Zamboni
- ETH Zürich, Institute of Molecular Systems Biology, Zurich, Switzerland
| | - Aurélien Bailly
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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11
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Kałużna M, Fischer‐Le Saux M, Pothier JF, Jacques M, Obradović A, Tavares F, Stefani E. Xanthomonas arboricola pv. juglandis and pv. corylina: Brothers or distant relatives? Genetic clues, epidemiology, and insights for disease management. MOLECULAR PLANT PATHOLOGY 2021; 22:1481-1499. [PMID: 34156749 PMCID: PMC8578823 DOI: 10.1111/mpp.13073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/06/2021] [Accepted: 04/23/2021] [Indexed: 05/31/2023]
Abstract
BACKGROUND The species Xanthomonas arboricola comprises up to nine pathovars, two of which affect nut crops: pv. juglandis, the causal agent of walnut bacterial blight, brown apical necrosis, and the vertical oozing canker of Persian (English) walnut; and pv. corylina, the causal agent of the bacterial blight of hazelnut. Both pathovars share a complex population structure, represented by different clusters and several clades. Here we describe our current understanding of symptomatology, population dynamics, epidemiology, and disease control. TAXONOMIC STATUS Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Lysobacterales (earlier synonym of Xanthomonadales); Family Lysobacteraceae (earlier synonym of Xanthomonadaceae); Genus Xanthomonas; Species X. arboricola; Pathovars: pv. juglandis and pv. corylina. HOST RANGE AND SYMPTOMS The host range of each pathovar is not limited to a single species, but each infects mainly one plant species: Juglans regia (X. arboricola pv. juglandis) and Corylus avellana (X. arboricola. pv. corylina). Walnut bacterial blight is characterized by lesions on leaves and fruits, and cankers on twigs, branches, and trunks; brown apical necrosis symptoms consist of apical necrosis originating at the stigmatic end of the fruit. A peculiar symptom, the vertical oozing canker developing along the trunk, is elicited by a particular genetic lineage of the bacterium. Symptoms of hazelnut bacterial blight are visible on leaves and fruits as necrotic lesions, and on woody parts as cankers. A remarkable difference is that affected walnuts drop abundantly, whereas hazelnuts with symptoms do not. DISTRIBUTION Bacterial blight of walnut has a worldwide distribution, wherever Persian (English) walnut is cultivated; the bacterial blight of hazelnut has a more limited distribution, although disease outbreaks are currently more frequently reported. X. arboricola pv. juglandis is regulated almost nowhere, whereas X. arboricola pv. corylina is regulated in most European and Mediterranean Plant Protection Organization (EPPO) countries. EPIDEMIOLOGY AND CONTROL For both pathogens infected nursery material is the main pathway for their introduction and spread into newly cultivated areas; additionally, infected nursery material is the source of primary inoculum. X. arboricola pv. juglandis is also disseminated through pollen. Disease control is achieved through the phytosanitary certification of nursery material (hazelnut), although approved certification schemes are not currently available. Once the disease is present in walnut/hazelnut groves, copper compounds are widely used, mostly in association with dithiocarbamates; where allowed, antibiotics (preferably kasugamycin) are sprayed. The emergence of strains highly resistant to copper currently represents the major threat for effective management of the bacterial blight of walnut. USEFUL WEBSITES: https://gd.eppo.int/taxon/XANTJU, https://gd.eppo.int/taxon/XANTCY, https://www.euroxanth.eu, http://www.xanthomonas.org.
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Affiliation(s)
- Monika Kałużna
- The National Institute of Horticultural ResearchSkierniewicePoland
| | | | - Joël F. Pothier
- Environmental Genomics and Systems Biology Research GroupInstitute for Natural Resource SciencesZurich University of Applied SciencesWädenswilSwitzerland
| | | | | | - Fernando Tavares
- Centro de Investigação em Biodiversidade e Recursos GenéticosLaboratório Associado (CIBIO‐InBIO)Universidade do PortoPortugal
- Faculdade de CiênciasDepartamento de BiologiaUniversidade do PortoPortoPortugal
| | - Emilio Stefani
- Department of Life SciencesUniversity of Modena and Reggio EmiliaReggio EmiliaItaly
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12
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Moretti C, Rezzonico F, Orfei B, Cortese C, Moreno‐Pérez A, van den Burg HA, Onofri A, Firrao G, Ramos C, Smits THM, Buonaurio R. Synergistic interaction between the type III secretion system of the endophytic bacterium Pantoea agglomerans DAPP-PG 734 and the virulence of the causal agent of olive knot Pseudomonas savastanoi pv. savastanoi DAPP-PG 722. MOLECULAR PLANT PATHOLOGY 2021; 22:1209-1225. [PMID: 34268839 PMCID: PMC8435235 DOI: 10.1111/mpp.13105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/09/2021] [Accepted: 06/16/2021] [Indexed: 05/29/2023]
Abstract
The endophytic bacterium Pantoea agglomerans DAPP-PG 734 was previously isolated from olive knots caused by infection with Pseudomonas savastanoi pv. savastanoi DAPP-PG 722. Whole-genome analysis of this P. agglomerans strain revealed the presence of a Hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To assess the role of the P. agglomerans T3SS in the interaction with P. savastanoi pv. savastanoi, we generated independent knockout mutants in three Hrp genes of the P. agglomerans DAPP-PG 734 T3SS (hrpJ, hrpN, and hrpY). In contrast to the wildtype control, all three mutants failed to cause a hypersensitive response when infiltrated in tobacco leaves, suggesting that P. agglomerans T3SS is functional and injects effector proteins in plant cells. In contrast to P. savastanoi pv. savastanoi DAPP-PG 722, the wildtype strain P. agglomerans DAPP-PG 734 and its Hrp T3SS mutants did not cause olive knot disease in 1-year-old olive plants. Coinoculation of P. savastanoi pv. savastanoi with P. agglomerans wildtype strains did not significantly change the knot size, while the DAPP-PG 734 hrpY mutant induced a significant decrease in knot size, which could be complemented by providing hrpY on a plasmid. By epifluorescence microscopy and confocal laser scanning microscopy, we found that the localization patterns in knots were nonoverlapping for P. savastanoi pv. savastanoi and P. agglomerans when coinoculated. Our results suggest that suppression of olive plant defences mediated by the Hrp T3SS of P. agglomerans DAPP-PG 734 positively impacts the virulence of P. savastanoi pv. savastanoi DAPP-PG 722.
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Affiliation(s)
- Chiaraluce Moretti
- Dipartimento di Scienze Agrarie, Alimentari e AmbientaliUniversità degli Studi di PerugiaPerugiaItaly
| | - Fabio Rezzonico
- Environmental Genomics and Systems Biology Research GroupInstitute of Natural Resource SciencesZurich University of Applied Sciences ZHAWWädenswilSwitzerland
| | - Benedetta Orfei
- Dipartimento di Scienze Agrarie, Alimentari e AmbientaliUniversità degli Studi di PerugiaPerugiaItaly
| | - Chiara Cortese
- Dipartimento di Scienze Agrarie, Alimentari e AmbientaliUniversità degli Studi di PerugiaPerugiaItaly
| | - Alba Moreno‐Pérez
- Área de GenéticaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”Universidad de Málaga‐Consejo Superior de Investigaciones CientíficasMálagaSpain
| | - Harrold A. van den Burg
- Molecular Plant PathologySwammerdam Institute for Life SciencesUniversity of AmsterdamAmsterdamNetherlands
| | - Andrea Onofri
- Dipartimento di Scienze Agrarie, Alimentari e AmbientaliUniversità degli Studi di PerugiaPerugiaItaly
| | - Giuseppe Firrao
- Dipartimento di Scienze Agroalimentati Ambientali e AnimaliUniversità degli Studi di UdineUdineItaly
| | - Cayo Ramos
- Área de GenéticaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”Universidad de Málaga‐Consejo Superior de Investigaciones CientíficasMálagaSpain
| | - Theo H. M. Smits
- Environmental Genomics and Systems Biology Research GroupInstitute of Natural Resource SciencesZurich University of Applied Sciences ZHAWWädenswilSwitzerland
| | - Roberto Buonaurio
- Dipartimento di Scienze Agrarie, Alimentari e AmbientaliUniversità degli Studi di PerugiaPerugiaItaly
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13
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Jo Y, Back CG, Kim KH, Chu H, Lee JH, Moh SH, Cho WK. Comparative Study of Metagenomics and Metatranscriptomics to Reveal Microbiomes in Overwintering Pepper Fruits. Int J Mol Sci 2021; 22:6202. [PMID: 34201359 PMCID: PMC8227054 DOI: 10.3390/ijms22126202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/05/2021] [Accepted: 06/05/2021] [Indexed: 12/19/2022] Open
Abstract
Red pepper (Capsicum annuum, L.), is one of the most important spice plants in Korea. Overwintering pepper fruits are a reservoir of various microbial pepper diseases. Here, we conducted metagenomics (DNA sequencing) and metatranscriptomics (RNA sequencing) using samples collected from three different fields. We compared two different library types and three different analytical methods for the identification of microbiomes in overwintering pepper fruits. Our results demonstrated that DNA sequencing might be useful for the identification of bacteria and DNA viruses such as bacteriophages, while mRNA sequencing might be beneficial for the identification of fungi and RNA viruses. Among three analytical methods, KRAKEN2 with raw data reads (KRAKEN2_R) might be superior for the identification of microbial species to other analytical methods. However, some microbial species with a low number of reads were wrongly assigned at the species level by KRAKEN2_R. Moreover, we found that the databases for bacteria and viruses were better established as compared to the fungal database with limited genome data. In summary, we carefully suggest that different library types and analytical methods with proper databases should be applied for the purpose of microbiome study.
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Affiliation(s)
- Yeonhwa Jo
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (Y.J.); (K.-H.K.)
| | - Chang-Gi Back
- Horticultural and Herbal Crop Environment Division, National Institute of Horticultural and Herbal Science, RDA, Wanju 55365, Korea;
| | - Kook-Hyung Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (Y.J.); (K.-H.K.)
| | - Hyosub Chu
- R&D Division, BERTIS Inc., Seongnam-si 13605, Korea;
| | - Jeong Hun Lee
- Anti-Aging Research Institute of BIO-FD&C Co., Ltd., Incheon 21990, Korea; (J.H.L.); (S.H.M.)
| | - Sang Hyun Moh
- Anti-Aging Research Institute of BIO-FD&C Co., Ltd., Incheon 21990, Korea; (J.H.L.); (S.H.M.)
| | - Won Kyong Cho
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (Y.J.); (K.-H.K.)
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14
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Ponce GE, Fuse M, Chan A, Connor EF. The Localization of Phytohormones within the Gall-inducing Insect Eurosta solidaginis (Diptera: Tephritidae). ARTHROPOD-PLANT INTERACTIONS 2021; 15:375-385. [PMID: 34149963 PMCID: PMC8211092 DOI: 10.1007/s11829-021-09817-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
The phytohormone production hypothesis suggests that organisms, including insects, induce galls by producing and secreting plant growth hormones. Auxins and cytokinins are classes of phytohormones that induce cell growth and cell division, which could contribute to the plant tissue proliferation which constitutes the covering gall. Bacteria, symbiotic with insects, may also play a part in gall induction by insects through the synthesis of phytohormones or other effectors. Past studies have shown that concentrations of cytokinins and auxins in gall-inducing insects are higher than in their host plants. However, these analyses have involved whole-body extractions. Using immunolocalization of cytokinin and auxin, in the gall inducing stage of Eurosta solidaginis, we found both phytohormones to localize almost exclusively to the salivary glands. Co-localization of phytohormone label with a nucleic acid stain in the salivary glands revealed the absence of Wolbachia sp., the bacterial symbiont of E. solidaginis, which suggests that phytohormone production is symbiont independent. Our findings are consistent with the hypothesis that phytohormones are synthesized in and secreted from the salivary glands of E. solidaginis into host-plant tissues for the purpose of manipulating the host plant.
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Affiliation(s)
- Gabriela E Ponce
- Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA USA 94132
| | - Megumi Fuse
- Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA USA 94132
| | - Annette Chan
- Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA USA 94132
| | - Edward F Connor
- Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA USA 94132
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15
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Soluch R, Hülter NF, Romero Picazo D, Özkurt E, Stukenbrock EH, Dagan T. Colonization dynamics of Pantoea agglomerans in the wheat root habitat. Environ Microbiol 2021; 23:2260-2273. [PMID: 33587819 DOI: 10.1111/1462-2920.15430] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 02/09/2021] [Indexed: 01/27/2023]
Abstract
Plants are colonized by microbial communities that have diverse implications for plant development and health. The establishment of a stable plant-bacteria interaction depends on a continuous coexistence over generations. Transmission via the seed is considered as the main route for vertical inheritance of plant-associated bacteria. Nonetheless, the ecological principles that govern the plant colonization by seed endophytes remain understudied. Here we quantify the contribution of arrival time and colonization history to bacterial colonization of the wheat root. Establishing a common seed endophyte, Pantoea agglomerans, and wheat as a model system enabled us to document bacterial colonization of the plant roots during the early stages of germination. Using our system, we estimate the carrying capacity of the wheat roots as 108 cells g-1 , which is robust among individual plants and over time. Competitions in planta reveal a significant advantage of early incoming colonizers over late-incoming colonizers. Priming for the wheat environment had little effect on the colonizer success. Our experiments thus provide empirical data on the root colonization dynamics of a seed endophyte. The persistence of seed endophyte bacteria with the plant population over generations may contribute to the stable transmission that is one route for the evolution of a stable host-associated lifestyle.
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Affiliation(s)
- Ryszard Soluch
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Am Botanischen Garten 11, Kiel, 24118, Germany
| | - Nils F Hülter
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Am Botanischen Garten 11, Kiel, 24118, Germany
| | - Devani Romero Picazo
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Am Botanischen Garten 11, Kiel, 24118, Germany
| | - Ezgi Özkurt
- Environmental Genomics, Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany.,Environmental Genomics, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, Plön, 24306, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany.,Environmental Genomics, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, Plön, 24306, Germany
| | - Tal Dagan
- Institute of General Microbiology, Christian-Albrechts University of Kiel, Am Botanischen Garten 11, Kiel, 24118, Germany
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16
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Zhao X, Gao L, Huang H, Zhao Y, Hanif A, Wu H, Gu Q, Wu L, Gao X. Exploring the pathogenic function of Pantoea ananatis endogenous plasmid by an efficient and simple plasmid elimination strategy. Microbiol Res 2021; 246:126710. [PMID: 33556709 DOI: 10.1016/j.micres.2021.126710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/23/2020] [Accepted: 01/22/2021] [Indexed: 10/22/2022]
Abstract
The bacterium Pantoea ananatis is associated with devastating plant diseases that cause serious economic losses. Strain DZ-12 was previously isolated from maize brown rot leaves in Hebei Province, China and its genome sequencing revealed that it belongs to P. ananatis. It contains a large, endogenous plasmid, pDZ-12. Different studies have shown that virulence determinants are frequently carried on plasmids. To determine whether pDZ-12 from P. ananatis has any effect on pathogenicity, the plasmid was eliminated by substituting its native replication genes with temperature-sensitive replication genes. The resulting temperature-sensitive plasmid could be cured by growing cells at high temperature (37℃). Loss of pDZ-12 from P. ananatis DZ-12 led to a decreased disease severity in maize plants suggesting that the endogenous plasmid is important for pathogenesis. Loss of pDZ-12 also affected the ability of the bacterium to form biofilms. The study provides the first evidence that the endogenous plasmid of P. ananatis DZ-12 is important for pathogenesis in maize plants and carries genes involved in biofilm formation. This study also presents the first report on curing a plasmid from P. ananatis.
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Affiliation(s)
- Xiaozhen Zhao
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Lu Gao
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Hai Huang
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Yi Zhao
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Alvina Hanif
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Huijun Wu
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Qin Gu
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Liming Wu
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China
| | - Xuewen Gao
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of Education, Nanjing 210095, China.
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17
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Abstract
Population genomics is transforming our understanding of pathogen biology and evolution, and contributing to the prevention and management of disease in diverse crops. We provide an overview of key methods in bacterial population genomics and describe recent work focusing on three topics of critical importance to plant pathology: (i) resolving pathogen origins and transmission pathways during outbreak events, (ii) identifying the genetic basis of host specificity and virulence, and (iii) understanding how pathogens evolve in response to changing agricultural practices.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Christina Straub
- Institute of Environmental Science and Research, Health and Environment, Auckland, New Zealand
- Genomics Aotearoa, New Zealand
| | - Elena Colombi
- Curtin Health Innovation Research Institute (CHIRI), Curtin University, Perth, Western Australia, Australia
- School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Western Australia, Australia
| | - Honour C McCann
- New Zealand Institute for Advanced Study, Massey University, Albany, New Zealand
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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18
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Richard D, Pruvost O, Balloux F, Boyer C, Rieux A, Lefeuvre P. Time-calibrated genomic evolution of a monomorphic bacterium during its establishment as an endemic crop pathogen. Mol Ecol 2020; 30:1823-1835. [PMID: 33305421 DOI: 10.1111/mec.15770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 01/03/2023]
Abstract
Horizontal gene transfer is of major evolutionary importance as it allows for the redistribution of phenotypically important genes among lineages. Such genes with essential functions include those involved in resistance to antimicrobial compounds and virulence factors in pathogenic bacteria. Understanding gene turnover at microevolutionary scales is critical to assess the pace of this evolutionary process. Here, we characterized and quantified gene turnover for the epidemic lineage of a bacterial plant pathogen of major agricultural importance worldwide. Relying on a dense geographic sampling spanning 39 years of evolution, we estimated both the dynamics of single nucleotide polymorphism accumulation and gene content turnover. We identified extensive gene content variation among lineages even at the smallest phylogenetic and geographic scales. Gene turnover rate exceeded nucleotide substitution rate by three orders of magnitude. Accessory genes were found preferentially located on plasmids, but we identified a highly plastic chromosomal region hosting ecologically important genes such as transcription activator-like effectors. Whereas most changes in the gene content are probably transient, the rapid spread of a mobile element conferring resistance to copper compounds widely used for the management of plant bacterial pathogens illustrates how some accessory genes can become ubiquitous within a population over short timeframes.
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Affiliation(s)
- Damien Richard
- Cirad, UMR PVBMT, Réunion, France.,ANSES, Plant Health Laboratory, Réunion, France.,Université de la Réunion, UMR PVBMT, Réunion, France
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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20
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Water Conservation and Plant Survival Strategies of Rhizobacteria under Drought Stress. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10111683] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Drylands are stressful environment for plants growth and production. Plant growth-promoting rhizobacteria (PGPR) acts as a rampart against the adverse impacts of drought stress in drylands and enhances plant growth and is helpful in agricultural sustainability. PGPR improves drought tolerance by implicating physio-chemical modifications called rhizobacterial-induced drought endurance and resilience (RIDER). The RIDER response includes; alterations of phytohormonal levels, metabolic adjustments, production of bacterial exopolysaccharides (EPS), biofilm formation, and antioxidant resistance, including the accumulation of many suitable organic solutes such as carbohydrates, amino acids, and polyamines. Modulation of moisture status by these PGPRs is one of the primary mechanisms regulating plant growth, but studies on their effect on plant survival are scarce in sandy/desert soil. It was found that inoculated plants showed high tolerance to water-deficient conditions by delaying dehydration and maintaining the plant’s water status at an optimal level. PGPR inoculated plants had a high recovery rate after rewatering interms of similar biomass at flowering compared to non-stressed plants. These rhizobacteria enhance plant tolerance and also elicit induced systemic resistance of plants to water scarcity. PGPR also improves the root growth and root architecture, thereby improving nutrient and water uptake. PGPR promoted accumulation of stress-responsive plant metabolites such as amino acids, sugars, and sugar alcohols. These metabolites play a substantial role in regulating plant growth and development and strengthen the plant’s defensive system against various biotic and abiotic stresses, in particular drought stress.
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21
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Tsai AYL, Oota M, Sawa S. Chemotactic Host-Finding Strategies of Plant Endoparasites and Endophytes. FRONTIERS IN PLANT SCIENCE 2020; 11:1167. [PMID: 32849722 PMCID: PMC7411241 DOI: 10.3389/fpls.2020.01167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/20/2020] [Indexed: 05/04/2023]
Abstract
Plants interact with microorganisms in the environment during all stages of their development and in most of their organs. These interactions can be either beneficial or detrimental for the plant and may be transient or long-term. In extreme cases, microorganisms become endoparastic or endophytic and permanently reside within a plant, while the host plant undergoes developmental reprogramming and produces new tissues or organs as a response to the invasion. Events at the cellular and molecular level following infection have been extensively described, however the mechanisms of how these microorganisms locate their plant hosts via chemotaxis remain largely unknown. In this review, we summarize recent findings concerning the signalling molecules that regulate chemotaxis of endoparasitic/endophytic bacteria, fungi, and nematodes. In particular, we will focus on the molecules secreted by plants that are most likely to act as guidance cues for microorganisms. These compounds are found in a wide range of plant species and show a variety of secondary effects. Interestingly, these compounds show different attraction potencies depending on the species of the invading organism, suggesting that cues perceived in the soil may be more complex than anticipated. However, what the cognate receptors are for these attractants, as well as the mechanism of how these attractants influence these organisms, remain important outstanding questions. Host-targeting marks the first step of plant-microorganism interactions, therefore understanding the signalling molecules involved in this step plays a key role in understanding these interactions as a whole.
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Zhang H, Zhang Q, Chen S, Zhang Z, Song J, Long Z, Yu Y, Fang H. Enterobacteriaceae predominate in the endophytic microbiome and contribute to the resistome of strawberry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 727:138708. [PMID: 32334231 DOI: 10.1016/j.scitotenv.2020.138708] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 05/21/2023]
Abstract
Antibiotic resistance genes (ARGs) harbored by plant microbiomes have been implicated as a potential risk to public health via food chain, especially directly edible fruits and vegetables. Here, we investigated the microbiome and antibiotic resistome in soil-strawberry ecosystem using shotgun metagenomic sequencing. The results showed that the enterobacterial population dominated the endophytes of strawberry fruits. Moreover, 85 subtypes of ARGs, including several clinically important ARGs, were detected in the strawberry fruit metagenomes. Additionally, host tracking analysis in combination with antibiotic-resistant bacterial isolate screening suggested that fruit-borne ARGs were mainly carried by members of the Enterobacteriaceae family. Unexpectedly, most of fruit-borne isolates were found to be resistant to several clinically important antimicrobials, e.g., erythromycin and cephalexin. Our findings provide broad insights into endophytic antibiotic resistomes of direct edible strawberry fruits and their potential hosts, and highlight the potential exposure risks of plant microbiomes to the human food chain.
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Affiliation(s)
- Houpu Zhang
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Qianke Zhang
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Shiyu Chen
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Zihan Zhang
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Jiajin Song
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Zhengnan Long
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Yunlong Yu
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Hua Fang
- Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China; Key laboratory of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, China; Key laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou 310058, China.
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23
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Nissan G, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I. Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens. MOLECULAR PLANT PATHOLOGY 2019; 20:1582-1587. [PMID: 31368647 PMCID: PMC6804341 DOI: 10.1111/mpp.12860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.
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Affiliation(s)
- Gal Nissan
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Guido Sessa
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Isaac Barash
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
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24
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Gutiérrez-Barranquero JA, Cazorla FM, Torés JA, de Vicente A. Pantoea agglomerans as a New Etiological Agent of a Bacterial Necrotic Disease of Mango Trees. PHYTOPATHOLOGY 2019; 109:17-26. [PMID: 30102576 DOI: 10.1094/phyto-06-18-0186-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Bacterial apical necrosis of mango trees, a disease elicited by Pseudomonas syringae pv. syringae, is a primary limiting factor of mango crop production in the Mediterranean region. In this study, a collection of bacterial isolates associated with necrotic symptoms in mango trees similar to those produced by bacterial apical necrosis disease were isolated over five consecutive years in orchards from the Canary Islands. The bacterial isolates were characterized and identified as Pantoea agglomerans. Pathogenicity tests conducted on onion bulbs and mango plants confirmed that P. agglomerans strains isolated from mango trees are a new etiological agent of a bacterial necrotic disease in the Canary Islands. Pathogenicity plasmids of the pPATH family have been previously reported in P. agglomerans. The majority of putatively pathogenic (n = 23) and pathogenic (n = 4) P. agglomerans strains isolated from mango trees harbored four plasmids, one of which was close in size to the 135-kb pPATH pathogenicity plasmid. The analysis of the presence of two major genes in pPATH plasmids (repA and hrpJ) was undertaken in P. agglomerans strains isolated from mango trees. The hrpJ gene was detected in the 140-kb plasmid of pathogenic P. agglomerans strains isolated from mango trees but it showed differences in nucleotide sequences compared with other pathogenic strains. In contrast, the repA gene was not detected in any of the putatively pathogenic and pathogenic P. agglomerans strains isolated from mango trees. Finally, genetic characterization and phylogenetic analysis using the hrpJ gene and the housekeeping genes gyrB and rpoB showed that almost all P. agglomerans strains that were putatively pathogenic and pathogenic on mango trees clustered together, forming a differentiated phylogroup with respect to the other pathogenic P. agglomerans strains described from other hosts.
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Affiliation(s)
- José A Gutiérrez-Barranquero
- First, second, and fourth authors: Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain; and third author: IHSM-UMA-CSIC, Estación Experimental "La Mayora", 29750 Algarrobo-Costa (Málaga), Spain
| | - Francisco M Cazorla
- First, second, and fourth authors: Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain; and third author: IHSM-UMA-CSIC, Estación Experimental "La Mayora", 29750 Algarrobo-Costa (Málaga), Spain
| | - Juan Antonio Torés
- First, second, and fourth authors: Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain; and third author: IHSM-UMA-CSIC, Estación Experimental "La Mayora", 29750 Algarrobo-Costa (Málaga), Spain
| | - Antonio de Vicente
- First, second, and fourth authors: Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain; and third author: IHSM-UMA-CSIC, Estación Experimental "La Mayora", 29750 Algarrobo-Costa (Málaga), Spain
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25
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Nissan G, Gershovits M, Morozov M, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I, Pupko T. Revealing the inventory of type III effectors in Pantoea agglomerans gall-forming pathovars using draft genome sequences and a machine-learning approach. MOLECULAR PLANT PATHOLOGY 2018; 19:381-392. [PMID: 28019708 PMCID: PMC6638007 DOI: 10.1111/mpp.12528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/06/2016] [Accepted: 12/14/2016] [Indexed: 05/03/2023]
Abstract
Pantoea agglomerans, a widespread epiphytic bacterium, has evolved into a hypersensitive response and pathogenicity (hrp)-dependent and host-specific gall-forming pathogen by the acquisition of a pathogenicity plasmid containing a type III secretion system (T3SS) and its effectors (T3Es). Pantoea agglomerans pv. betae (Pab) elicits galls on beet (Beta vulgaris) and gypsophila (Gypsophila paniculata), whereas P. agglomerans pv. gypsophilae (Pag) incites galls on gypsophila and a hypersensitive response (HR) on beet. Draft genome sequences were generated and employed in combination with a machine-learning approach and a translocation assay into beet roots to identify the pools of T3Es in the two pathovars. The genomes of the sequenced Pab4188 and Pag824-1 strains have a similar size (∼5 MB) and GC content (∼55%). Mutational analysis revealed that, in Pab4188, eight T3Es (HsvB, HsvG, PseB, DspA/E, HopAY1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on beet and gypsophila. In Pag824-1, nine T3Es (HsvG, HsvB, PthG, DspA/E, HopAY1, HopD1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on gypsophila, whereas the PthG effector triggers HR on beet. HsvB, HsvG, PthG and PseB appear to endow pathovar specificities to Pab and Pag, and no homologous T3Es were identified for these proteins in other phytopathogenic bacteria. Conversely, the remaining T3Es contribute to the virulence of both pathovars, and homologous T3Es were found in other phytopathogenic bacteria. Remarkably, HsvG and HsvB, which act as host-specific transcription factors, displayed the largest contribution to disease development.
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Affiliation(s)
- Gal Nissan
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Michael Gershovits
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Michael Morozov
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Tal Pupko
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
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26
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Kunkel BN, Harper CP. The roles of auxin during interactions between bacterial plant pathogens and their hosts. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:245-254. [PMID: 29272462 DOI: 10.1093/jxb/erx447] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant pathogens have evolved several strategies to manipulate the biology of their hosts to facilitate colonization, growth to high levels in plant tissue, and production of disease. One of the less well known of these strategies is the synthesis of plant hormones and hormone analogs, and there is growing evidence that modulation of host hormone signaling is important during pathogenesis. Several plant pathogens produce the auxin indole-3-acetic acid (IAA) and/or virulence factors that modulate host auxin signaling. Auxin is well known for being involved in many aspects of plant growth and development, but recent findings have revealed that elevated IAA levels or enhanced auxin signaling can also promote disease development in some plant-pathogen interactions. In addition to stimulating plant cell growth during infection by gall-forming bacteria, auxin and auxin signaling can antagonize plant defense responses. Auxin can also act as a microbial signaling molecule to impact the biology of some pathogens directly. In this review, we summarize recent progress towards elucidating the roles that auxin production, modification of host auxin signaling, and direct effects of auxin on pathogens play during pathogenesis, with emphasis on the impacts of auxin on interactions with bacterial pathogens.
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Affiliation(s)
- Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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27
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Zdorovenko EL, Kadykova AA, Shashkov AS, Varbanets LD, Bulyhina TV, Knirel YA. Lipopolysaccharide of Pantoea agglomerans 7969: Chemical identification, function and biological activity. Carbohydr Polym 2017; 165:351-358. [PMID: 28363559 DOI: 10.1016/j.carbpol.2017.02.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/14/2017] [Accepted: 02/14/2017] [Indexed: 10/20/2022]
Abstract
Lipopolysaccharide (LPS) of Pantoea agglomerans 7969 isolated from apple tree was purified and characterized chemically by sugar and fatty acid analysis. Lipid A was analysed by negative-ion mode ESI MS and found to consist mainly of hexa- and tetra-acyl species typical of E. coli lipid A. The O-specific polysaccharide of the LPS was studied by sugar analysis, Smith degradation, and one- and two-dimensional 1H and 13C NMR spectroscopy. The polysaccharide is built up of linear tetrasaccharide repeating units, and about ∼25% repeats contain glycerol 1-phosphate on the GlcNAc residue: →3)-α-l-Rha p-(1→6)-α-d-Man p-(1→3)-α-d-Fuc p-(1→3)-β-d-Glc pNAc-(1→∼25% Gro-1-P-(O→6)⌋ The LPS showed low levels of toxic and pyrogenic activities and reduced the average adhesion and the index of adhesiveness.
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Affiliation(s)
- Evelina L Zdorovenko
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 119991 Moscow, Russia.
| | - Alexandra A Kadykova
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 119991 Moscow, Russia
| | - Alexander S Shashkov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 119991 Moscow, Russia
| | - Ludmila D Varbanets
- D.K. Zabolotny Insitute of Microbiology and Virology of the National Academy of Sciences, 154 Zabolotnoho Str., 03143 Kiev, Ukraine
| | - Tetiana V Bulyhina
- D.K. Zabolotny Insitute of Microbiology and Virology of the National Academy of Sciences, 154 Zabolotnoho Str., 03143 Kiev, Ukraine
| | - Yuriy A Knirel
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, 119991 Moscow, Russia
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28
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Jacques MA, Arlat M, Boulanger A, Boureau T, Carrère S, Cesbron S, Chen NWG, Cociancich S, Darrasse A, Denancé N, Fischer-Le Saux M, Gagnevin L, Koebnik R, Lauber E, Noël LD, Pieretti I, Portier P, Pruvost O, Rieux A, Robène I, Royer M, Szurek B, Verdier V, Vernière C. Using Ecology, Physiology, and Genomics to Understand Host Specificity in Xanthomonas. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:163-87. [PMID: 27296145 DOI: 10.1146/annurev-phyto-080615-100147] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
How pathogens coevolve with and adapt to their hosts are critical to understanding how host jumps and/or acquisition of novel traits can lead to new disease emergences. The Xanthomonas genus includes Gram-negative plant-pathogenic bacteria that collectively infect a broad range of crops and wild plant species. However, individual Xanthomonas strains usually cause disease on only a few plant species and are highly adapted to their hosts, making them pertinent models to study host specificity. This review summarizes our current understanding of the molecular basis of host specificity in the Xanthomonas genus, with a particular focus on the ecology, physiology, and pathogenicity of the bacterium. Despite our limited understanding of the basis of host specificity, type III effectors, microbe-associated molecular patterns, lipopolysaccharides, transcriptional regulators, and chemotactic sensors emerge as key determinants for shaping host specificity.
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Affiliation(s)
- Marie-Agnès Jacques
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Matthieu Arlat
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, F-31062 Toulouse, France
| | - Alice Boulanger
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
- Université de Toulouse, Université Paul Sabatier, F-31062 Toulouse, France
| | - Tristan Boureau
- Université Angers, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France;
| | - Sébastien Carrère
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
| | - Sophie Cesbron
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Nicolas W G Chen
- Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France;
| | - Stéphane Cociancich
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Armelle Darrasse
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Nicolas Denancé
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Marion Fischer-Le Saux
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Lionel Gagnevin
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Ralf Koebnik
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Emmanuelle Lauber
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
| | - Laurent D Noël
- INRA, UMR 441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France; , , , ,
- CNRS, UMR 2594 Laboratoire des Interactions Plantes Micro-organismes (LIPM), F-31326 Castanet-Tolosan, France
| | - Isabelle Pieretti
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Perrine Portier
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), F-49071 Beaucouzé, France; , , , , ,
| | - Olivier Pruvost
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Adrien Rieux
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Isabelle Robène
- CIRAD, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), F-97410 Saint-Pierre, La Réunion, France; , ,
| | - Monique Royer
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
| | - Boris Szurek
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Valérie Verdier
- IRD, CIRAD, University of Montpellier, Interactions Plantes Micro-organismes Environnement (IPME), F-34394 Montpellier, France; , , ,
| | - Christian Vernière
- CIRAD, UMR Biologie et Génétique des Interactions Plante-Parasite (BGPI), F-34398 Montpellier, France; , , ,
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29
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Palmer M, de Maayer P, Poulsen M, Steenkamp ET, van Zyl E, Coutinho TA, Venter SN. Draft genome sequences of Pantoea agglomerans and Pantoea vagans isolates associated with termites. Stand Genomic Sci 2016; 11:23. [PMID: 26937267 PMCID: PMC4774006 DOI: 10.1186/s40793-016-0144-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/20/2016] [Indexed: 02/02/2023] Open
Abstract
The genus Pantoea incorporates many economically and clinically important species. The plant-associated species, Pantoea agglomerans and Pantoea vagans, are closely related and are often isolated from similar environments. Plasmids conferring certain metabolic capabilities are also shared amongst these two species. The genomes of two isolates obtained from fungus-growing termites in South Africa were sequenced, assembled and annotated. A high number of orthologous genes are conserved within and between these species. The difference in genome size between P. agglomerans MP2 (4,733,829 bp) and P. vagans MP7 (4,598,703 bp) can largely be attributed to the differences in plasmid content. The genome sequences of these isolates may shed light on the common traits that enable P. agglomerans and P. vagans to co-occur in plant- and insect-associated niches.
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Affiliation(s)
- Marike Palmer
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />DST-NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa
| | - Pieter de Maayer
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, 0002 South Africa
| | - Michael Poulsen
- />Department of Biology, Centre for Social Evolution, Section for Ecology and Evolution, University of Copenhagen, Univeritetsparken 15, 2100 Copenhagen East, Denmark
| | - Emma T. Steenkamp
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />DST-NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa
| | - Elritha van Zyl
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />DST-NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa
| | - Teresa A. Coutinho
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />DST-NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa
| | - Stephanus N. Venter
- />Department of Microbiology and Plant Pathology and the Genome Research Institute, University of Pretoria, Pretoria, 0002 South Africa
- />DST-NRF Centre of Excellence in Tree Health Biotechnology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa
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30
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Mining the genome of Rhodococcus fascians, a plant growth-promoting bacterium gone astray. N Biotechnol 2016; 33:706-717. [PMID: 26877150 DOI: 10.1016/j.nbt.2016.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022]
Abstract
Rhodococcus fascians is a phytopathogenic Gram-positive Actinomycete with a very broad host range encompassing especially dicotyledonous herbaceous perennials, but also some monocots, such as the Liliaceae and, recently, the woody crop pistachio. The pathogenicity of R. fascians strain D188 is known to be encoded by the linear plasmid pFiD188 and to be dictated by its capacity to produce a mixture of cytokinins. Here, we show that D188-5, the nonpathogenic plasmid-free derivative of the wild-type strain D188 actually has a plant growth-promoting effect. With the availability of the genome sequence of R. fascians, the chromosome of strain D188 was mined for putative plant growth-promoting functions and the functionality of some of these activities was tested. This analysis together with previous results suggests that the plant growth-promoting activity of R. fascians is due to production of plant growth modulators, such as auxin and cytokinin, combined with degradation of ethylene through 1-amino-cyclopropane-1-carboxylic acid deaminase. Moreover, R. fascians has several functions that could contribute to efficient colonization and competitiveness, but there is little evidence for a strong impact on plant nutrition. Possibly, the plant growth promotion encoded by the D188 chromosome is imperative for the epiphytic phase of the life cycle of R. fascians and prepares the plant to host the bacteria, thus ensuring proper continuation into the pathogenic phase.
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31
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Bartoli C, Roux F, Lamichhane JR. Molecular mechanisms underlying the emergence of bacterial pathogens: an ecological perspective. MOLECULAR PLANT PATHOLOGY 2016; 17:303-10. [PMID: 26062772 PMCID: PMC6638374 DOI: 10.1111/mpp.12284] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The rapid emergence of new bacterial diseases negatively affects both human health and agricultural productivity. Although the molecular mechanisms underlying these disease emergences are shared between human- and plant-pathogenic bacteria, not much effort has been made to date to understand disease emergences caused by plant-pathogenic bacteria. In particular, there is a paucity of information in the literature on the role of environmental habitats in which plant-pathogenic bacteria evolve and on the stress factors to which these microbes are unceasingly exposed. In this microreview, we focus on three molecular mechanisms underlying pathogenicity in bacteria, namely mutations, genomic rearrangements and the acquisition of new DNA sequences through horizontal gene transfer (HGT). We briefly discuss the role of these mechanisms in bacterial disease emergence and elucidate how the environment can influence the occurrence and regulation of these molecular mechanisms by directly impacting disease emergence. The understanding of such molecular evolutionary mechanisms and their environmental drivers will represent an important step towards predicting bacterial disease emergence and developing sustainable management strategies for crops.
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Affiliation(s)
- Claudia Bartoli
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), INRA, UMR441, F-31326, Castanet-Tolosan, France
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), CNRS, UMR2594, F-31326, Castanet-Tolosan, France
| | - Fabrice Roux
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), INRA, UMR441, F-31326, Castanet-Tolosan, France
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), CNRS, UMR2594, F-31326, Castanet-Tolosan, France
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White JA, Richards NK, Laugraud A, Saeed A, Curry MM, McNeill MR. Endosymbiotic candidates for parasitoid defense in exotic and native New Zealand weevils. MICROBIAL ECOLOGY 2015; 70:274-86. [PMID: 25613091 DOI: 10.1007/s00248-014-0561-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 12/23/2014] [Indexed: 05/26/2023]
Abstract
Some insects are infected with maternally inherited bacterial endosymbionts that protect them against pathogens or parasitoids. The weevil Sitona obsoletus (=Sitona lepidus) is invasive in New Zealand, and suspected to contain such defensive symbionts, because it is particularly resistant to a Moroccan strain of the parasitoid Microctonus aethiopoides (which successfully attacks many other weevil species), and shows geographic variation in susceptibility to an Irish strain of the same parasitoid. Using 454 pyrosequencing, we investigated the bacterial community associated with S. obsoletus, two other exotic weevils (Sitona discoideus and Listronotus bonariensis) and two endemic New Zealand weevils (Irenimus aequalis and Steriphus variabilis). We found that S. obsoletus was infected by one strain of Wolbachia and two strains of Rickettsia, none of which were found in any other weevil species examined. Using diagnostic PCR, we found that S. obsoletus in the Northland region, where parasitism is highly variable, were primarily infected with Wolbachia and Rickettsia strain 2, indicating that these two symbionts should be investigated for potential defensive properties. In comparison, S. discoideus lacked any apparent maternally inherited bacterial endosymbionts. In the other weevil species, we found a different strain of Wolbachia and two different strains of Spiroplasma. Two weevil species (St. variabilis and L. bonariensis) were infected with distinct strains of Nardonella, the ancestral endosymbiont of weevils, whereas three weevil species (S. obsoletus, S. discoideus, and I. aequalis) lacked evidence for Nardonella infection. However, I. aequalis was consistently infected with a novel Enterobacteriaceae strain, suggesting that a symbiont replacement may have taken place, similar to that described for other weevil clades.
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Affiliation(s)
- Jennifer A White
- Department of Entomology, University of Kentucky, Lexington, KY, 40546, USA,
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A Transmissible Plasmid-Borne Pathogenicity Island Confers Piscibactin Biosynthesis in the Fish Pathogen Photobacterium damselae subsp. piscicida. Appl Environ Microbiol 2015; 81:5867-79. [PMID: 26092457 DOI: 10.1128/aem.01580-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/15/2015] [Indexed: 11/20/2022] Open
Abstract
The fish pathogen Photobacterium damselae subsp. piscicida produces the siderophore piscibactin. A gene cluster that resembles the Yersinia high-pathogenicity island (HPI) encodes piscibactin biosynthesis. Here, we report that this HPI-like cluster is part of a hitherto-uncharacterized 68-kb plasmid dubbed pPHDP70. This plasmid lacks homologs of genes that mediate conjugation, but we found that it could be transferred at low frequencies from P. damselae subsp. piscicida to a mollusk pathogenic Vibrio alginolyticus strain and to other Gram-negative bacteria, likely dependent on the conjugative functions of the coresident plasmid pPHDP60. Following its conjugative transfer, pPHDP70 restored the capacity of a vibrioferrin mutant of V. alginolyticus to grow under low-iron conditions, and piscibactin became detectable in its supernatant. Thus, pPHDP70 appears to harbor all the genes required for piscibactin biosynthesis and transport. P. damselae subsp. piscicida strains cured of pPHDP70 no longer produced piscibactin, had impaired growth under iron-limited conditions, and exhibited markedly decreased virulence in fish. Collectively, our findings highlight the importance of pPHDP70, with its capacity for piscibactin-mediated iron acquisition, in the virulence of P. damselae subsp. piscicida. Horizontal transmission of this plasmid-borne piscibactin synthesis gene cluster in the marine environment may facilitate the emergence of new pathogens.
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Harris MO, Friesen TL, Xu SS, Chen MS, Giron D, Stuart JJ. Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:513-531. [PMID: 25504642 DOI: 10.1093/jxb/eru465] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this review, we argue for a research initiative on wheat's responses to biotic stress. One goal is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to a variety of agents of biotic stress are integrated in an important crop. We propose gene-for-gene interactions as the focus of the research initiative. On the parasite's side is an Avirulence (Avr) gene that encodes one of the many effector proteins the parasite applies to the plant to assist with colonization. On the plant's side is a Resistance (R) gene that mediates a surveillance system that detects the Avr protein directly or indirectly and triggers effector-triggered plant immunity. Even though arthropods are responsible for a significant proportion of plant biotic stress, they have not been integrated into important models of plant immunity that come from plant pathology. A roadblock has been the absence of molecular evidence for arthropod Avr effectors. Thirty years after this evidence was discovered in a plant pathogen, there is now evidence for arthropods with the cloning of the Hessian fly's vH13 Avr gene. After reviewing the two models of plant immunity, we discuss how arthropods could be incorporated. We end by showing features that make wheat an interesting system for plant immunity, including 479 resistance genes known from agriculture that target viruses, bacteria, fungi, nematodes, insects, and mites. It is not likely that humans will be subsisting on Arabidopsis in the year 2050. It is time to start understanding how agricultural plants integrate responses to biotic stress.
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Affiliation(s)
- M O Harris
- Department of Entomology, North Dakota State University, Fargo, ND 58105, USA
| | - T L Friesen
- USDA-ARS, Cereal Crops Research Unit, Fargo, ND USA
| | - S S Xu
- USDA-ARS, Cereal Crops Research Unit, Fargo, ND USA
| | - M S Chen
- USDA-ARS, Hard Winter Wheat Genetics Research Unit, Kansas State University, Manhattan, KS, USA
| | - D Giron
- Institut de Recherche sur la Biologie de l'Insecte UMR 7261 CNRS/Université François-Rabelais de Tours, Tours, France
| | - J J Stuart
- Department of Entomology, Purdue University, West Lafayette, IN, USA
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Buonaurio R, Moretti C, da Silva DP, Cortese C, Ramos C, Venturi V. The olive knot disease as a model to study the role of interspecies bacterial communities in plant disease. FRONTIERS IN PLANT SCIENCE 2015; 6:434. [PMID: 26113855 PMCID: PMC4461811 DOI: 10.3389/fpls.2015.00434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/27/2015] [Indexed: 05/03/2023]
Abstract
There is an increasing interest in studying interspecies bacterial interactions in diseases of animals and plants as it is believed that the great majority of bacteria found in nature live in complex communities. Plant pathologists have thus far mainly focused on studies involving single species or on their interactions with antagonistic competitors. A bacterial disease used as model to study multispecies interactions is the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi (Psv). Knots caused by Psv in branches and other aerial parts of the olive trees are an ideal niche not only for the pathogen but also for many other plant-associated bacterial species, mainly belonging to the genera Pantoea, Pectobacterium, Erwinia, and Curtobacterium. The non-pathogenic bacterial species Erwinia toletana, Pantoea agglomerans, and Erwinia oleae, which are frequently isolated inside the olive knots, cooperate with Psv in modulating the disease severity. Co-inoculations of these species with Psv result in bigger knots and better bacterial colonization when compared to single inoculations. Moreover, harmless bacteria co-localize with the pathogen inside the knots, indicating the formation of stable bacterial consortia that may facilitate the exchange of quorum sensing signals and metabolites. Here we discuss the possible role of bacterial communities in the establishment and development of olive knot disease, which we believe could be taking place in many other bacterial plant diseases.
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Affiliation(s)
- Roberto Buonaurio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
- *Correspondence: Roberto Buonaurio, Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Via Borgo XX Giugno, 74 06121 Perugia, Italy,
| | - Chiaraluce Moretti
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
| | | | - Chiara Cortese
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
| | - Cayo Ramos
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Vittorio Venturi
- Bacteriology Group, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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Jackson RW, Vinatzer B, Arnold DL, Dorus S, Murillo J. The influence of the accessory genome on bacterial pathogen evolution. Mob Genet Elements 2014; 1:55-65. [PMID: 22016845 DOI: 10.4161/mge.1.1.16432] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/09/2011] [Accepted: 05/10/2011] [Indexed: 01/15/2023] Open
Abstract
Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens' frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorize the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution.
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Affiliation(s)
- Robert W Jackson
- School of Biological Sciences; University of Reading; Whiteknights; Reading, UK
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Almario J, Muller D, Défago G, Moënne-Loccoz Y. Rhizosphere ecology and phytoprotection in soils naturally suppressive to Thielaviopsis black root rot of tobacco. Environ Microbiol 2014; 16:1949-60. [PMID: 24650207 DOI: 10.1111/1462-2920.12459] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/16/2014] [Indexed: 11/27/2022]
Abstract
Soil suppressiveness to disease is an intriguing emerging property in agroecosystems, with important implications because it enables significant protection of susceptible plants from soil-borne pathogens. Unlike many soils where disease suppressiveness requires crop monoculture to establish, certain soils are naturally suppressive to disease, and this type of specific disease suppressiveness is maintained despite crop rotation. Soils naturally suppressive to Thielaviopsis basicola-mediated black root rot of tobacco and other crops occur in Morens region (Switzerland) and have been studied for over 30 years. In Morens, vermiculite-rich suppressive soils formed on morainic deposits while illite-rich conducive soils developed on sandstone, but suppressiveness is of microbial origin. Antagonistic pseudomonads play a role in black root rot suppressiveness, including Pseudomonas protegens (formerly P. fluorescens) CHA0, a major model strain for research. However, other types of rhizobacterial taxa may differ in prevalence between suppressive and conducive soils, suggesting that the microbial basis of black root rot suppressiveness could be far more complex than solely a Pseudomonas property. This first review on black root rot suppressive soils covers early findings on these soils, the significance of recent results, and compares them with other types of suppressive soils in terms of rhizosphere ecology and plant protection mechanisms.
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Affiliation(s)
- Juliana Almario
- Université de Lyon, F-69622, Lyon, France; Université Lyon 1, Villeurbanne, France; CNRS, UMR5557, Ecologie Microbienne, Villeurbanne, France
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Spaepen S, Bossuyt S, Engelen K, Marchal K, Vanderleyden J. Phenotypical and molecular responses of Arabidopsis thaliana roots as a result of inoculation with the auxin-producing bacterium Azospirillum brasilense. THE NEW PHYTOLOGIST 2014; 201:850-861. [PMID: 24219779 DOI: 10.1111/nph.12590] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/24/2013] [Indexed: 05/18/2023]
Abstract
The auxin-producing bacterium Azospirillum brasilense Sp245 can promote the growth of several plant species. The model plant Arabidopsis thaliana was chosen as host plant to gain an insight into the molecular mechanisms that govern this interaction. The determination of differential gene expression in Arabidopsis roots after inoculation with either A. brasilense wild-type or an auxin biosynthesis mutant was achieved by microarray analysis. Arabidopsis thaliana inoculation with A. brasilense wild-type increases the number of lateral roots and root hairs, and elevates the internal auxin concentration in the plant. The A. thaliana root transcriptome undergoes extensive changes on A. brasilense inoculation, and the effects are more pronounced at later time points. The wild-type bacterial strain induces changes in hormone- and defense-related genes, as well as in plant cell wall-related genes. The A. brasilense mutant, however, does not elicit these transcriptional changes to the same extent. There are qualitative and quantitative differences between A. thaliana responses to the wild-type A. brasilense strain and the auxin biosynthesis mutant strain, based on both phenotypic and transcriptomic data. This illustrates the major role played by auxin in the Azospirillum-Arabidopsis interaction, and possibly also in other bacterium-plant interactions.
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Affiliation(s)
- Stijn Spaepen
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001, Heverlee, Belgium
| | - Stijn Bossuyt
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001, Heverlee, Belgium
| | - Kristof Engelen
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001, Heverlee, Belgium
- Fondazione Edmund Mach, Research and Innovation Centre, Via E. Mach, 1, 38010, San Michele all'Adige, Trento, Italy
| | - Kathleen Marchal
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001, Heverlee, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Gent, Belgium
| | - Jos Vanderleyden
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, 3001, Heverlee, Belgium
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Aviv G, Tsyba K, Steck N, Salmon-Divon M, Cornelius A, Rahav G, Grassl GA, Gal-Mor O. A unique megaplasmid contributes to stress tolerance and pathogenicity of an emergent Salmonella enterica serovar Infantis strain. Environ Microbiol 2014; 16:977-94. [PMID: 24320043 DOI: 10.1111/1462-2920.12351] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 11/30/2013] [Indexed: 11/30/2022]
Abstract
Of all known Salmonella enterica serovars, S. Infantis is one of the most commonly isolated and has been recently emerging worldwide. To understand the recent emergence of S. Infantis in Israel, we performed extensive comparative analyses between pre-emergent and the clonal emergent S. Infantis populations. We demonstrate the fixation of adaptive mutations in the DNA gyrase (gyrA) and nitroreductase (nfsA) genes, conferring resistance to quinolones and nitrofurans, respectively, and the carriage of an emergent-specific plasmid, designated pESI. This self-transferred episome is a mosaic megaplasmid (∼280 kb), which increases bacterial tolerance to environmental mercury (mer operon) and oxidative stress, and provides further resistance to tetracycline, sulfamethoxazole and trimethoprim, most likely due to the presence of tetRA, sulI and dfrA genes respectively. Moreover, pESI carries the yersiniabactin siderophore system and two novel chaperone-usher fimbriae. In vitro studies established that pESI conjugation into a plasmidless S. Infantis strain results in superior biofilm formation, adhesion and invasion into avian and mammalian host cells. In vivo mouse infections demonstrated higher pathogenicity and increased intestinal inflammation caused by an S. Infantis strain harboring pESI compared with the plasmidless parental strain. Our results indicate that the presence of pESI that was found only in the emergent population of S. Infantis in Israel contributes significantly to antimicrobials tolerance and pathogenicity of its carrier. It is highly likely that pESI plays a key role in the successful spread of the emergent clone that replaced the local S. Infantis community in the short time of only 2-3 years.
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Affiliation(s)
- Gili Aviv
- The Infectious Diseases Research Laboratory, Tel-Hashomer, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
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Abstract
In this article, I briefly recount the historical events in my native country that led me to become a plant pathologist. I started as a field pathologist specializing in fungal diseases of legumes, moved to biochemical research on virulence factors, and then on to molecular plant-microbe interactions. I describe the impact my graduate studies at the University of California (UC)-Davis had on my career. My life's work and teaching can be said to reflect the development in plant pathology during the past 40 years. I have included a concise review of the development of plant pathology in Israel and the ways it is funded. Dealing with administrative duties while conducting research has contributed to my belief in the importance of multidisciplinary approaches and of preserving the applied approach in the teaching of plant pathology.
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Affiliation(s)
- Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel;
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Hoffman MT, Gunatilaka MK, Wijeratne K, Gunatilaka L, Arnold AE. Endohyphal bacterium enhances production of indole-3-acetic acid by a foliar fungal endophyte. PLoS One 2013; 8:e73132. [PMID: 24086270 PMCID: PMC3782478 DOI: 10.1371/journal.pone.0073132] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/23/2013] [Indexed: 11/19/2022] Open
Abstract
Numerous plant pathogens, rhizosphere symbionts, and endophytic bacteria and yeasts produce the important phytohormone indole-3-acetic acid (IAA), often with profound effects on host plants. However, to date IAA production has not been documented among foliar endophytes -- the diverse guild of primarily filamentous Ascomycota that live within healthy, above-ground tissues of all plant species studied thus far. Recently bacteria that live within hyphae of endophytes (endohyphal bacteria) have been detected, but their effects have not been studied previously. Here we show not only that IAA is produced in vitro by a foliar endophyte (here identified as Pestalotiopsis aff. neglecta, Xylariales), but that IAA production is enhanced significantly when the endophyte hosts an endohyphal bacterium (here identified as Luteibacter sp., Xanthomonadales). Both the endophyte and the endophyte/bacterium complex appear to rely on an L-tryptophan dependent pathway for IAA synthesis. The bacterium can be isolated from the fungus when the symbiotic complex is cultivated at 36°C. In pure culture the bacterium does not produce IAA. Culture filtrate from the endophyte-bacterium complex significantly enhances growth of tomato in vitro relative to controls and to filtrate from the endophyte alone. Together these results speak to a facultative symbiosis between an endophyte and endohyphal bacterium that strongly influences IAA production, providing a new framework in which to explore endophyte-plant interactions.
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Affiliation(s)
- Michele T. Hoffman
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, United States of America
| | - Malkanthi K. Gunatilaka
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, United States of America
| | - Kithsiri Wijeratne
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, Tucson, Arizona, United States of America
| | - Leslie Gunatilaka
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, Tucson, Arizona, United States of America
| | - A. Elizabeth Arnold
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Panijel M, Chalupowicz L, Sessa G, Manulis-Sasson S, Barash I. Global regulatory networks control the hrp regulon of the gall-forming bacterium Pantoea agglomerans pv. gypsophilae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1031-1043. [PMID: 23745675 DOI: 10.1094/mpmi-04-13-0097-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Gall formation by Pantoea agglomerans pv. gypsophilae is dependent on the hypersensitive response and pathogenicity (hrp) system. Previous studies demonstrated that PagR and PagI, regulators of the quorum-sensing system, induce expression of the hrp regulatory cascade (i.e., hrpXY, hrpS, and hrpL) that activates the HrpL regulon. Here, we isolated the genes of the Gac/Rsm global regulatory pathway (i.e., gacS, gacA, rsmB, and csrD) and of the post-transcriptional regulator rsmA. Our results demonstrate that PagR and PagI also upregulate expression of the Gac/Rsm pathway. PagR acts as a transcriptional activator of each of the hrp regulatory genes and gacA in a N-butanoyl-L-homoserine lactone-dependent manner as shown by gel shift experiments. Mutants of the Gac/Rsm genes or overexpression of rsmA significantly reduced Pantoea agglomerans virulence and colonization of gypsophila. Overexpression of rsmB sRNA abolished gall formation, colonization, and hypersensitive reaction on nonhost plants and prevented transcription of the hrp regulatory cascade, indicating a lack of functional type III secretion system. Expression of rsmB sRNA in the background of the csrD null mutant suggests that CsrD may act as a safeguard for preventing excessive production of rsmB sRNA. Results presented indicate that the hrp regulatory cascade is controlled directly by PagR and indirectly by RsmA, whereas deficiency in RsmA activity is epistatic to PagR induction.
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Affiliation(s)
- Mary Panijel
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, Tel-Aviv, Israel
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Nacoulma AP, Vandeputte OM, De Lorenzi M, El Jaziri M, Duez P. Metabolomic-based study of the leafy gall, the ecological niche of the phytopathogen Rhodococcus fascians, as a potential source of bioactive compounds. Int J Mol Sci 2013; 14:12533-49. [PMID: 23771021 PMCID: PMC3709798 DOI: 10.3390/ijms140612533] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/21/2013] [Accepted: 06/04/2013] [Indexed: 01/27/2023] Open
Abstract
Leafy gall is a plant hyperplasia induced upon Rhodococcus fascians infection. Previously, by genomic and transcriptomic analysis, it has been reported that, at the early stage of symptom development, both primary and secondary metabolisms are modified. The present study is based on the hypothesis that fully developed leafy gall, could represent a potential source of new bioactive compounds. Therefore, non-targeted metabolomic analysis of aqueous and chloroform extracts of leafy gall and non-infected tobacco was carried out by 1H-NMR coupled to principal component analysis (PCA) and orthogonal projections to latent structures-discriminant analysis (OPLS-DA). Polar metabolite profiling reflects modifications mainly in the primary metabolites and in some polyphenolics. In contrast, main modifications occurring in non-polar metabolites concern secondary metabolites, and gas chromatography and mass spectrometry (GC-MS) evidenced alterations in diterpenoids family. Analysis of crude extracts of leafy galls and non-infected tobacco leaves exhibited a distinct antiproliferative activity against all four tested human cancer cell lines. A bio-guided fractionation of chloroformic crude extract yield to semi-purified fractions, which inhibited proliferation of glioblastoma U373 cells with IC50 between 14.0 and 2.4 µg/mL. Discussion is focused on the consequence of these metabolic changes, with respect to plant defense mechanisms following infection. Considering the promising role of diterpenoid family as bioactive compounds, leafy gall may rather be a propitious source for drug discovery.
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Affiliation(s)
- Aminata P. Nacoulma
- Laboratory of Toxicology, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/1, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
| | - Olivier M. Vandeputte
- Laboratory of Plant Biotechnology, Faculty of Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium; E-Mails: (O.M.V.); (M.E.J.)
| | - Manuella De Lorenzi
- Laboratory of Toxicology, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/1, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
| | - Mondher El Jaziri
- Laboratory of Plant Biotechnology, Faculty of Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium; E-Mails: (O.M.V.); (M.E.J.)
| | - Pierre Duez
- Laboratory of Pharmacognosy, Bromatology and Human Nutrition, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/9, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
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Structure of the O-antigen of the lipopolysaccharide isolated from Pantoea ananatis AEP17, a rhizobacterium associated with rice. Carbohydr Res 2013; 369:25-30. [DOI: 10.1016/j.carres.2012.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 11/19/2022]
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Chalupowicz L, Weinthal D, Gaba V, Sessa G, Barash I, Manulis-Sasson S. Polar auxin transport is essential for gall formation by Pantoea agglomerans on Gypsophila. MOLECULAR PLANT PATHOLOGY 2013; 14:185-90. [PMID: 23083316 PMCID: PMC6638636 DOI: 10.1111/j.1364-3703.2012.00839.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The virulence of the bacterium Pantoea agglomerans pv. gypsophilae (Pag) on Gypsophila paniculata depends on a type III secretion system (T3SS) and its effectors. The hypothesis that plant-derived indole-3-acetic acid (IAA) plays a major role in gall formation was examined by disrupting basipetal polar auxin transport with the specific inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-naphthylphthalamic acid (NPA). On inoculation with Pag, galls developed in gypsophila stems above but not below lanolin rings containing TIBA or NPA, whereas, in controls, galls developed above and below the rings. In contrast, TIBA and NPA could not inhibit tumour formation in tomato caused by Agrobacterium tumefaciens. The colonization of gypsophila stems by Pag was reduced below, but not above, the lanolin-TIBA ring. Following Pag inoculation and TIBA treatment, the expression of hrpL (a T3SS regulator) and pagR (a quorum-sensing transcriptional regulator) decreased four-fold and that of pthG (a T3SS effector) two-fold after 24 h. Expression of PIN2 (a putative auxin efflux carrier) increased 35-fold, 24 h after Pag inoculation. However, inoculation with a mutant in the T3SS effector pthG reduced the expression of PIN2 by two-fold compared with wild-type infection. The results suggest that pthG might govern the elevation of PIN2 expression during infection, and that polar auxin transport-derived IAA is essential for gall initiation.
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Affiliation(s)
- Laura Chalupowicz
- Department of Plant Pathology and Weed Research, ARO, Volcani Center, Bet Dagan 50250, Israel
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Ghannoum MA, Mukherjee PK, Jurevic RJ, Retuerto M, Brown RE, Sikaroodi M, Webster-Cyriaque J, Gillevet PM. Metabolomics reveals differential levels of oral metabolites in HIV-infected patients: toward novel diagnostic targets. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2013; 17:5-15. [PMID: 21751871 PMCID: PMC3545316 DOI: 10.1089/omi.2011.0035] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The objective of the current study was to characterize the profile of oral metabolites in HIV-infected patients using metabolomics. Oral wash samples were collected from 12 HIV-infected and 12 healthy individuals (matched for age, sex, and ethnicity), processed, and analyzed by metabolomics. We detected 198 identifiable and 85 nonidentifiable metabolites; 27 identifiable metabolites were differentially present (12 increased, 15 decreased) in HIV-infected patients. Elevated metabolites included p-cresol sulfate, nucleotides (e.g., allantoin), and amino acids (e.g., phenylalanine, tryptophan), whereas decreased oral metabolites included fucose, fumarate, and N-acetylglucosamine. Pathway network analysis revealed the largest multinode network in healthy versus HIV-infected patients to involve carbohydrate biosynthesis and degradation. HIV-infected patients on antiretroviral therapy (ART) showed the largest number (12) of statistically significant metabolite correlation differences compared with healthy controls. Interestingly, the oral phenlyalanine:tyrosine ratio increased in ART-naive HIV-infected patients (mean ± SEM = 2.58 ± 0.87) compared with healthy individuals (1.33 ± 0.10, p = 0.062) or ART-experienced patients (1.78 ± 0.30, p = 0.441). This is the first study to reveal differential levels of oral metabolites in HIV-infected patients compared withj healthy volunteers, and that oral phenlyalanine:tyrosine ratio may be a useful marker for noninvasive monitoring of the immune status during HIV infection.
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Affiliation(s)
- Mahmoud A Ghannoum
- Center for Medical Mycology, Case Western Reserve University, Ohio 44106-5028, USA.
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De Maayer P, Chan WY, Blom J, Venter SN, Duffy B, Smits THM, Coutinho TA. The large universal Pantoea plasmid LPP-1 plays a major role in biological and ecological diversification. BMC Genomics 2012; 13:625. [PMID: 23151240 PMCID: PMC3505739 DOI: 10.1186/1471-2164-13-625] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 11/11/2012] [Indexed: 11/21/2022] Open
Abstract
Background Pantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by which this occurs among bacteria is through the acquisition and maintenance of plasmids. Here, we have analyzed and compared the sequences of a large plasmid common to all sequenced Pantoea spp. Results and discussion The Large PantoeaPlasmids (LPP-1) of twenty strains encompassing seven different Pantoea species, including pathogens and endo-/epiphytes of a wide range of plant hosts as well as insect-associated strains, were compared. The LPP-1 plasmid sequences range in size from ~281 to 794 kb and carry between 238 and 750 protein coding sequences (CDS). A core set of 46 proteins, encompassing 2.2% of the total pan-plasmid (2,095 CDS), conserved among all LPP-1 plasmid sequences, includes those required for thiamine and pigment biosynthesis. Phylogenetic analysis reveals that these plasmids have arisen from an ancestral plasmid, which has undergone extensive diversification. Analysis of the proteins encoded on LPP-1 also showed that these plasmids contribute to a wide range of Pantoea phenotypes, including the transport and catabolism of various substrates, inorganic ion assimilation, resistance to antibiotics and heavy metals, colonization and persistence in the host and environment, pathogenesis and antibiosis. Conclusions LPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid. LPP-1 encodes a large array of proteins that have played a major role in the adaptation of the different Pantoea spp. to their various ecological niches and their specialization as pathogens, biocontrol agents or benign saprophytes found in many diverse environments.
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Affiliation(s)
- Pieter De Maayer
- Forestry and Agricultural Biotechnology Institute, Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, South Africa.
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Martinson EO, Herre EA, Machado CA, Arnold AE. Culture-free survey reveals diverse and distinctive fungal communities associated with developing figs (Ficus spp.) in Panama. MICROBIAL ECOLOGY 2012; 64:1073-1084. [PMID: 22729017 DOI: 10.1007/s00248-012-0079-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 05/30/2012] [Indexed: 06/01/2023]
Abstract
The ancient association of figs (Ficus spp.) and their pollinating wasps (fig wasps; Chalcidoidea, Hymenoptera) is one of the most interdependent plant-insect mutualisms known. In addition to pollinating wasps, a diverse community of organisms develops within the microcosm of the fig inflorescence and fruit. To better understand the multipartite context of the fig-fig wasp association, we used a culture-free approach to examine fungal communities associated with syconia of six species of Ficus and their pollinating wasps in lowland Panama. Diverse fungi were recovered from surface-sterilized flowers of all Ficus species, including gall- and seed flowers at four developmental stages. Fungal communities in syconia and on pollinating wasps were similar, dominated by diverse and previously unknown Saccharomycotina, and distinct from leaf- and stem endophyte communities in the same region. Before pollination, fungal communities were similar between gall- and seed flowers and among Ficus species. However, fungal communities differed significantly in flowers after pollination vs. before pollination, and between anciently diverged lineages of Ficus with active vs. passive pollination syndromes. Within groups of relatively closely related figs, there was little evidence for strict-sense host specificity between figs and particular fungal species. Instead, mixing of fungal communities among related figs, coupled with evidence for possible transfer by pollinating wasps, is consistent with recent suggestions of pollinator mixing within syconia. In turn, changes in fungal communities during fig development and ripening suggest an unexplored role of yeasts in the context of the fig-pollinator wasp mutualism.
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Affiliation(s)
- Ellen O Martinson
- Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ 85721, USA
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Patten CL, Blakney AJC, Coulson TJD. Activity, distribution and function of indole-3-acetic acid biosynthetic pathways in bacteria. Crit Rev Microbiol 2012; 39:395-415. [PMID: 22978761 DOI: 10.3109/1040841x.2012.716819] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The capacity to produce the phytohormone indole-3-acetic acid (IAA) is widespread among bacteria that inhabit diverse environments such as soils, fresh and marine waters, and plant and animal hosts. Three major pathways for bacterial IAA synthesis have been characterized that remove the amino and carboxyl groups from the α-carbon of tryptophan via the intermediates indolepyruvate, indoleacetamide, or indoleacetonitrile; the oxidized end product IAA is typically secreted. The enzymes in these pathways often catabolize a broad range of substrates including aromatic amino acids and in some cases the branched chain amino acids. Moreover, expression of some of the genes encoding key IAA biosynthetic enzymes is induced by all three aromatic amino acids. The broad distribution and substrate specificity of the enzymes suggests a role for these pathways beyond plant-microbe interactions in which bacterial IAA has been best studied.
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Affiliation(s)
- Cheryl L Patten
- Department of Biology, University of New Brunswick , Fredericton, New Brunswick , Canada
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Francis I, De Keyser A, De Backer P, Simón-Mateo C, Kalkus J, Pertry I, Ardiles-Diaz W, De Rycke R, Vandeputte OM, El Jaziri M, Holsters M, Vereecke D. pFiD188, the linear virulence plasmid of Rhodococcus fascians D188. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:637-47. [PMID: 22482837 DOI: 10.1094/mpmi-08-11-0215] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Rhodococcus fascians is currently the only phytopathogen of which the virulence genes occur on a linear plasmid. To get insight into the origin of this replicon and into the virulence strategy of this broad-spectrum phytopathogen, the sequence of the linear plasmid of strain D188, pFiD188, was determined. Analysis of the 198,917 bp revealed four syntenic regions with linear plasmids of R. erythropolis, R. jostii, and R. opacus, suggesting a common origin of these replicons. Mutational analysis of pFi_086 and pFi_102, similar to cutinases and type IV peptidases, respectively, showed that conserved region R2 was involved in plasmid dispersal and pointed toward a novel function for actinobacterial cutinases in conjugation. Additionally, pFiD188 had three regions that were unique for R. fascians. Functional analysis of the stk and nrp loci of regions U2 and U3, respectively, indicated that their role in symptom development was limited compared with that of the previously identified fas, att, and hyp virulence loci situated in region U1. Thus, pFiD188 is a typical rhodococcal linear plasmid with a composite structure that encodes core functions involved in plasmid maintenance and accessory functions, some possibly acquired through horizontal gene transfer, implicated in virulence and the interaction with the host.
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Affiliation(s)
- Isolde Francis
- Department of Plant Biotechnology and Bioinformatics, VIB, 9052 Gent, Belgium
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