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Nguyen LTT, Park AR, Van Le V, Hwang I, Kim JC. Exploration of a multifunctional biocontrol agent Streptomyces sp. JCK-8055 for the management of apple fire blight. Appl Microbiol Biotechnol 2024; 108:49. [PMID: 38183485 DOI: 10.1007/s00253-023-12874-w] [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: 06/14/2023] [Revised: 10/17/2023] [Accepted: 11/05/2023] [Indexed: 01/08/2024]
Abstract
Apple fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apple and pear trees. Biological control methods have attracted much attention from researchers to manage plant diseases as they are eco-friendly and viable alternatives to synthetic pesticides. Herein, we isolated Streptomyces sp. JCK-8055 from the root of pepper and investigated its mechanisms of action against E. amylovora. Streptomyces sp. JCK-8055 produced aureothricin and thiolutin, which antagonistically affect E. amylovora. JCK-8055 and its two active metabolites have a broad-spectrum in vitro activity against various phytopathogenic bacteria and fungi. They also effectively suppressed tomato bacterial wilt and apple fire blight in in vivo experiments. Interestingly, JCK-8055 colonizes roots as a tomato seed coating and induces apple leaf shedding at the abscission zone, ultimately halting the growth of pathogenic bacteria. Additionally, JCK-8055 can produce the plant growth regulation hormone indole-3-acetic acid (IAA) and hydrolytic enzymes, including protease, gelatinase, and cellulase. JCK-8055 treatment also triggered the expression of salicylate (SA) and jasmonate (JA) signaling pathway marker genes, such as PR1, PR2, and PR3. Overall, our findings demonstrate that Streptomyces sp. JCK-8055 can control a wide range of plant diseases, particularly apple fire blight, through a combination of mechanisms such as antibiosis and induced resistance, highlighting its excellent potential as a biocontrol agent. KEY POINTS: • JCK-8055 produces the systemic antimicrobial metabolites, aureothricin, and thiolutin. • JCK-8055 treatment upregulates PR gene expression in apple plants against E. amylovora. • JCK-8055 controls plant diseases with antibiotics and induced resistance.
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Affiliation(s)
- Loan Thi Thanh Nguyen
- Department of Agricultural Chemistry, College of Agriculture and Life Sciences, Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Ae Ran Park
- Department of Agricultural Chemistry, College of Agriculture and Life Sciences, Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Ve Van Le
- Cell Factory Research Centre, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Inmin Hwang
- Hygienic Safety and Analysis Center, World Institute of Kimchi, Gwangju, 61755, Republic of Korea
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, College of Agriculture and Life Sciences, Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju, 61186, Republic of Korea.
- JAN153 Biotech Incorporated, Gwangju, 61186, Republic of Korea.
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Kang IJ, Park Y, Roh E, Lee JH. Novel Single Nucleotide Variations Alter Pathogenicity in Korean Isolates of Erwinia amylovora. PLANT DISEASE 2024; 108:1174-1178. [PMID: 38105454 DOI: 10.1094/pdis-09-23-1836-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Erwinia amylovora, the causal agent of fire blight disease, has become a serious threat to the pome fruit industry in Korea since 2015. In this study, we showed that two new isolates of E. amylovora, Ea17-2187 and Ea19-7, obtained from pear orchards in Anseong, Korea, exhibited unique pathogenicity compared with other isolates thus far. Both were nonpathogenic to immature apple fruits but occasionally caused disease on immature pear fruits at varying reduced rates. Bioinformatic analyses revealed that their genomes are highly similar to those of the type strains TS3128 and ATCC49946 but have different mutations in essential virulence regulatory genes. Ea17-2187 has a single nucleotide substitution in rcsC, which encodes the core components of the Rcs system that activates the exopolysaccharide amylovoran production. In contrast, Ea19-7 contains a single nucleotide insertion in hrpL, which encodes a master regulator of the type III secretion system. In both cases, the mutation can cause premature termination and production of truncated gene products, disrupting virulence regulation. Introduction of the nonmutated rcsC and hrpL genes into Ea17-2187 and Ea19-7, respectively, fully recovered pathogenicity, comparable with that of TS3128; hence, these mutations were responsible for the altered pathogenicity observed. Interestingly, virulence assays on immature pear fruits showed that the hrpL mutant of Ea19-7 was still pathogenic, although its virulence level was markedly reduced. Taken together, these results suggest that the two new isolates might act as opportunistic pathogens or cheaters and that some Korean isolates might have evolved to acquire alternative pathways for activating pathogenicity factors.
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Affiliation(s)
- In-Jeong Kang
- Division of Crop Cultivation and Environment Research, National Institute of Crop Science, Suwon 16613, Korea
| | - Yejin Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
| | - Eunjung Roh
- Crop Protection Division, National Institute of Agricultural Science, Rural Development Administration, Wanju 55364, Korea
| | - Jae Hoon Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
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3
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Pilgrim J. Comparative genomics of a novel Erwinia species associated with the Highland midge ( Culicoides impunctatus). Microb Genom 2024; 10. [PMID: 38630610 DOI: 10.1099/mgen.0.001242] [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] [Indexed: 04/19/2024] Open
Abstract
Erwinia (Enterobacterales: Erwiniaceae) are a group of cosmopolitan bacteria best known as the causative agents of various plant diseases. However, other species in this genus have been found to play important roles as insect endosymbionts supplementing the diet of their hosts. Here, I describe Candidatus Erwinia impunctatus (Erwimp) associated with the Highland midge Culicoides impunctatus (Diptera: Ceratopogonidae), an abundant biting pest in the Scottish Highlands. The genome of this new Erwinia species was assembled using hybrid long and short read techniques, and a comparative analysis was undertaken with other members of the genus to understand its potential ecological niche and impact. Genome composition analysis revealed that Erwimp is similar to other endophytic and ectophytic species in the genus and is unlikely to be restricted to its insect host. Evidence for an additional plant host includes the presence of a carotenoid synthesis operon implicated as a virulence factor in plant-associated members in the sister genus Pantoea. Unique features of Erwimp include several copies of intimin-like proteins which, along with signs of genome pseudogenization and a loss of certain metabolic pathways, suggests an element of host restriction seen elsewhere in the genus. Furthermore, a screening of individuals over two field seasons revealed the absence of the bacteria in Culicoides impunctatus during the second year indicating this microbe-insect interaction is likely to be transient. These data suggest that Culicoides impunctatus may have an important role to play beyond a biting nuisance, as an insect vector transmitting Erwimp alongside any conferred impacts to surrounding biota.
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Affiliation(s)
- Jack Pilgrim
- Institute of Infection, Veterinary and Ecological Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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Hassani MA, Cui Z, LaReau J, Huntley RB, Steven B, Zeng Q. Inter-species interactions between two bacterial flower commensals and a floral pathogen reduce disease incidence and alter pathogen activity. mBio 2024; 15:e0021324. [PMID: 38376185 PMCID: PMC10936193 DOI: 10.1128/mbio.00213-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/21/2024] Open
Abstract
Flowers are colonized by a diverse community of microorganisms that can alter plant health and interact with floral pathogens. Erwinia amylovora is a flower-inhabiting bacterium and a pathogen that infects different plant species, including Malus × domestica (apple). Previously, we showed that the co-inoculation of two bacterial strains, members of the genera Pseudomonas and Pantoea, isolated from apple flowers, reduced disease incidence caused by this floral pathogen. Here, we decipher the ecological interactions between the two flower-associated bacteria and E. amylovora in field experimentation and in vitro co-cultures. The two flower commensal strains did not competitively exclude E. amylovora from the stigma habitat, as both bacteria and the pathogen co-existed on the stigma of apple flowers and in vitro. This suggests that plant protection might be mediated by other mechanisms than competitive niche exclusion. Using a synthetic stigma exudation medium, ternary co-culture of the bacterial strains led to a substantial alteration of gene expression in both the pathogen and the two microbiota members. Importantly, the gene expression profiles for the ternary co-culture were not just additive from binary co-cultures, suggesting that some functions only emerged in multipartite co-culture. Additionally, the ternary co-culture of the strains resulted in a stronger acidification of the growth milieu than mono- or binary co-cultures, pointing to another emergent property of co-inoculation. Our study emphasizes the critical role of emergent properties mediated by inter-species interactions within the plant holobiont and their potential impact on plant health and pathogen behavior. IMPORTANCE Fire blight, caused by Erwinia amylovora, is one of the most important plant diseases of pome fruits. Previous work largely suggested plant microbiota commensals suppressed disease by antagonizing pathogen growth. However, inter-species interactions of multiple flower commensals and their influence on pathogen activity and behavior have not been well studied. Here, we show that co-inoculating two bacterial strains that naturally colonize the apple flowers reduces disease incidence. We further demonstrate that the interactions between these two microbiota commensals and the floral pathogen led to the emergence of new gene expression patterns and a strong alteration of the external pH, factors that may modify the pathogen's behavior. Our findings emphasize the critical role of emergent properties mediated by inter-species interactions between plant microbiota and plant pathogens and their impact on plant health.
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Affiliation(s)
- M. Amine Hassani
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Zhouqi Cui
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Jacquelyn LaReau
- Department of Environmental Science and Forestry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Regan B. Huntley
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Blaire Steven
- Department of Environmental Science and Forestry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Quan Zeng
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
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Elmallawany MA, Abdel-Aal AA, Abu Eleinen KG, Nadar AH, El-Adawy AI, El-Dardiry MA, Abddel-Hafez YN, Kotb AA, Saif ATS, Shaheen HAA, Sayed A, Samir O, Alatyar AA, Sheble MA, Elnakib M, Badr MS, Nahnoush RK. Metagenomic analysis of the ocular toxoplasmosis in children uveitis from Fayoum governorate, Egypt. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 118:105551. [PMID: 38216107 DOI: 10.1016/j.meegid.2024.105551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/06/2024] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
Granulomatous anterior uveitis with single or numerous gelatinous nodules was found in children living in rural Egypt. All ocular diseases were originally thought to be water-born and related to digenic flukes. The current study sought to learn more about the causes of anterior granulomatous uveitis in Egyptian youngsters who used to swim in rural water canals. 50 children with eye lesions that had not responded to medical treatment were recruited. Four samples were surgically extracted and examined using real-time PCR, transmission electron microscopy (TEM), and shotgun metagenomic sequencing (SMS). Toxoplasma gondii was detected free within the syncytium's distal section, while the proximal part exhibited active synthesis of a presumably extra-polymeric material, possibly released by the microbial population. Toxoplasma gondii was found in 30 samples. Serologically, distinct anti-Toxoplasma antibodies were not found in 91.6% of patients. SMS showed that the T. gondii ME 49 strain had the greatest percentage (29-25%) in all samples within an Acinetobacter-containing microbial community. These findings suggested that these bacteria entered the body via the exterior route rather than the circulatory route. The lack of genetic evidence for subsequent parasite stages invalidates the prior findings about the assumed trematode stage.
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Affiliation(s)
- Marwa A Elmallawany
- Medical Parasitology Department, Faculty of Medicine Kasr Al-Ainy, Cairo University, 11796 Giza, Egypt
| | - Amany A Abdel-Aal
- Medical Parasitology Department, Faculty of Medicine Kasr Al-Ainy, Cairo University, 11796 Giza, Egypt; Postgraduate Department, Armed Forces College of Medicine (AFCM), 11774 Cairo, Egypt
| | - Khaled G Abu Eleinen
- Ophthalmology Department, Faculty of Medicine Kasr Al-Ainy, Cairo University, 11796 Giza, Egypt
| | | | - Azza I El-Adawy
- Medical Parasitology Department, Faculty of Medicine Kasr Al-Ainy, Cairo University, 11796 Giza, Egypt; Medical Parasitology Department, Armed Forces College of Medicine (AFCM), 11774 Cairo, Egypt
| | - Marwa A El-Dardiry
- Medical Parasitology Department, Faculty of Medicine, Fayoum University, 63511 Fayoum, Egypt.
| | - Yosra N Abddel-Hafez
- Medical Parasitology Department, Faculty of Medicine, Fayoum University, 63511 Fayoum, Egypt
| | - Ahmed A Kotb
- Ophthalmology Department, Faculty of Medicine, Fayoum University, 63511 Fayoum, Egypt
| | - Ahmed T S Saif
- Ophthalmology Department, Faculty of Medicine, Fayoum University, 63511 Fayoum, Egypt
| | - Hoda A A Shaheen
- Medical Parasitology Department, Faculty of Medicine, Girl's Campus, Al-Azhar University, 11682 Cairo, Egypt
| | - Ahmed Sayed
- Basic Research Unit, Genomics/Epigenomics Program, Children's Cancer Hospital 57357, 11562 Cairo, Egypt
| | - Omar Samir
- Basic Research Unit, Genomics/Epigenomics Program, Children's Cancer Hospital 57357, 11562 Cairo, Egypt
| | | | | | - Mostafa Elnakib
- Medical Microbiology and Immunology Department, Military Medical Academy, Cairo 11711, Egypt
| | - Mohamed S Badr
- Department of Molecular Biology and Bioinformatics, Medical Research Center, Faculty of Medicine, Ain Shams University, 11566 Cairo, Egypt
| | - Reham K Nahnoush
- Medical Parasitology Department, Faculty of Medicine Kasr Al-Ainy, Cairo University, 11796 Giza, Egypt; Medical Parasitology Department, Armed Forces College of Medicine (AFCM), 11774 Cairo, Egypt
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Klaewkla M, Wangpaiboon K, Pichyangkura R, Charoenwongpaiboon T. Unraveling the role of flexible coil near calcium binding site of levansucrase on thermostability and product profile via proline substitution and molecular dynamics simulations. Proteins 2024; 92:170-178. [PMID: 37753539 DOI: 10.1002/prot.26592] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 08/18/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023]
Abstract
Due to its bioactivity and versatile applications, levan has appeared as a promising biomaterial. Levansucrase is responsible for the conversion of sucrose into levan. With the goal of enhancing levan production, the strategy for enhancing the stability of levansucrase is being intensively studied. To make proteins more stable under high temperatures, proline, the most rigid residue, can be introduced into previously flexible regions. Herein, G249, D250, N251, and H252 on the flexible coil close to the calcium binding site of Bacillus licheniformis levansucrase were replaced with proline. Mutations at G249P greatly enhance both the enzyme's thermodynamic and kinetic stability, while those at H252P improve solely the enzyme's kinetic stability. GPC analysis revealed that G249P synthesize more levan, but H252P generate primarily oligosaccharides. Molecular dynamics simulations (MD) and MM/GBSA analysis revealed that G249P mutation increased not only the stability of levansucrase, but also affinity toward fructan.
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Affiliation(s)
| | - Karan Wangpaiboon
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Rath Pichyangkura
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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7
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Kharadi RR, Hsueh BY, Waters CM, Sundin GW. pGpG-signaling regulates virulence and global transcriptomic targets in Erwinia amylovora. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575434. [PMID: 38260453 PMCID: PMC10802605 DOI: 10.1101/2024.01.12.575434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cyclic-di-GMP (c-di-GMP) is a critical bacterial second messenger that enables the physiological phase transition in Erwinia amylovora, the phytopathogenic bacterium that causes fire blight disease. C-di-GMP generation is dependent on diguanylate cyclase enzymes while the degradation of c-di-GMP can occur through the action of phosphodiesterase (PDE) enzymes that contain an active EAL and/or a HD-GYP domain. The HD-GYP-type PDEs, which are absent in E. amylovora, can directly degrade c-di-GMP into two GMP molecules. PDEs that contain an active EAL domain, as found in all active PDEs in E. amylovora, degrade c-di-GMP into pGpG. The signaling function of pGpG is not fully understood in bacterial systems. A transcriptomic approach revealed that elevated levels of pGpG in E. amylovora impacted several genes involved in metabolic and regulatory functions including several type III secretion and extracellular appendage related genes. The heterologous overexpression of an EAL or HD-GYP-type PDE in different background E. amylovora strains with varying c-di-GMP levels revealed that in contrast to the generation of pGpG, the direct breakdown of c-di-GMP into GMP by the HD-GYP-type PDE led to an elevation in amylovoran production and biofilm formation despite a decrease in c-di-GMP levels. The breakdown of c-di-GMP into pGpG (as opposed to GTP) also led to a decrease in virulence in apple shoots. The expression of hrpS was significantly increased in response to the breakdown of c-di-GMP into pGpG. Further, our model suggests that a balance in the intracellular ratio of pGpG and c-di-GMP is essential for biofilm regulation in E. amylovora.
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Affiliation(s)
- Roshni R. Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Brian Y. Hsueh
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Christopher M. Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - George W. Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
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Xiao WN, Nunn GM, Fufeng AB, Belu N, Brookman RK, Halim A, Krysmanski EC, Cameron RK. Exploring Pseudomonas syringae pv. tomato biofilm-like aggregate formation in susceptible and PTI-responding Arabidopsis thaliana. MOLECULAR PLANT PATHOLOGY 2024; 25:e13403. [PMID: 37988240 PMCID: PMC10799205 DOI: 10.1111/mpp.13403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 11/23/2023]
Abstract
Bacterial biofilm-like aggregates have been observed in plants, but their role in pathogenicity is underinvestigated. In the present study, we observed that extracellular DNA and polysaccharides colocalized with green fluorescent protein (GFP)-expressing Pseudomonas syringae pv. tomato (Pst) aggregates in Arabidopsis leaves, suggesting that Pst aggregates are biofilms. GFP-expressing Pst, Pst ΔalgU ΔmucAB (Pst algU mutant), and Pst ΔalgD ΔalgU ΔmucAB (Pst algU algD mutant) were examined to explore the roles of (1) alginate, a potential biofilm component; (2) Pst AlgU, thought to regulate alginate biosynthesis and some type III secretion system effector genes; and (3) intercellular salicylic acid (SA) accumulation during pathogen-associated molecular pattern-triggered immunity (PTI). Pst formed extensive aggregates in susceptible plants, whereas aggregate numbers and size were reduced in Pst algU and Pst algD algU mutants, and both multiplied poorly in planta, suggesting that aggregate formation contributes to Pst success in planta. However, in SA-deficient sid2-2 plants, Pst algD algU mutant multiplication and aggregate formation were partially restored, suggesting plant-produced SA contributes to suppression of Pst aggregate formation. Pst algD algU mutants formed fewer and smaller aggregates than Pst algU mutants, suggesting both AlgU and AlgD contribute to Pst aggregate formation. Col-0 plants accumulated low levels of SA in response to Pst and both mutants (Pst algU and Pst algD algU), suggesting the regulatory functions of AlgU are not involved in suppressing SA-mediated plant defence. Plant PTI was associated with highly reduced Pst aggregate formation and accumulation of intercellular SA in flg22-induced PTI-responding wild-type Col-0, but not in PTI-incompetent fls2, suggesting intercellular SA accumulation by Arabidopsis contributes to suppression of Pst biofilm-like aggregate formation during PTI.
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Affiliation(s)
- Wantao N. Xiao
- Department of BiologyMcMaster UniversityHamiltonOntarioCanada
| | - Garrett M. Nunn
- Department of BiologyMcMaster UniversityHamiltonOntarioCanada
| | | | - Natalie Belu
- Department of BiologyMcMaster UniversityHamiltonOntarioCanada
| | | | - Abdul Halim
- Department of BiologyMcMaster UniversityHamiltonOntarioCanada
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Besarab NV, Letarova MA, Babenko VV, Belalov IS, Golomidova AK, Kulikov EE, Lagonenko AL, Evtushenkov AN, Letarov AV. The metastable associations of bacteriophages and Erwinia amylovora. Arch Microbiol 2023; 205:214. [PMID: 37129715 DOI: 10.1007/s00203-023-03550-8] [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: 02/12/2023] [Revised: 04/06/2023] [Accepted: 04/13/2023] [Indexed: 05/03/2023]
Abstract
Bacteriophages are often considered as possible agents of biological control of unwanted bacterial populations in medicine, agriculture and food industry. Although the virulent phages can efficiently kill the infected host cells but at the population level phage attack not always leads to the host population collapse but may result in establishment of a more or less stable co-existence. The mechanism of the long-term stabilization of the mixed phage-host cultures is poorly understood. Here we describe bacteriophages VyarbaL and Hena2, the members of the Molineuxvirinae and the Ounavirinae subfamilies, respectively, that are able to form the pseudolysogenic associations (PA) with their host Erwinia amylovora 1/79Sm on solid media. These PAs were stable through multiple passages. The phenomenon of the PA formation between a bacterial culture and bacteriophages decreases the effectiveness of bacteriophage-mediated biological control agents based on lytic bacteriophages.
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Affiliation(s)
- Natalya V Besarab
- Department of Molecular Biology, Faculty of Biology, Belarusian State University, Nezavisimisty Ave., 4, 220030, Minsk, Belarus.
| | - Maria A Letarova
- Research Center of Biotechnology of Russian Academy of Sciences, Winogradsky Institute of Microbiology, Pr. 60-Letiya Oktyabrya 7 Bld. 2, 117312, Moscow, Russia
| | - Vladislav V Babenko
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Ilya S Belalov
- Research Center of Biotechnology of Russian Academy of Sciences, Winogradsky Institute of Microbiology, Pr. 60-Letiya Oktyabrya 7 Bld. 2, 117312, Moscow, Russia
| | - Alla K Golomidova
- Research Center of Biotechnology of Russian Academy of Sciences, Winogradsky Institute of Microbiology, Pr. 60-Letiya Oktyabrya 7 Bld. 2, 117312, Moscow, Russia
| | - Eugene E Kulikov
- Research Center of Biotechnology of Russian Academy of Sciences, Winogradsky Institute of Microbiology, Pr. 60-Letiya Oktyabrya 7 Bld. 2, 117312, Moscow, Russia
| | - Alexander L Lagonenko
- Department of Molecular Biology, Faculty of Biology, Belarusian State University, Nezavisimisty Ave., 4, 220030, Minsk, Belarus
| | - Anatoly N Evtushenkov
- Department of Molecular Biology, Faculty of Biology, Belarusian State University, Nezavisimisty Ave., 4, 220030, Minsk, Belarus
| | - Andrey V Letarov
- Research Center of Biotechnology of Russian Academy of Sciences, Winogradsky Institute of Microbiology, Pr. 60-Letiya Oktyabrya 7 Bld. 2, 117312, Moscow, Russia
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10
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Deletion of pbpC Enhances Bacterial Pathogenicity on Tomato by Affecting Biofilm Formation, Exopolysaccharides Production, and Exoenzyme Activities in Clavibacter michiganensis. Int J Mol Sci 2023; 24:ijms24065324. [PMID: 36982399 PMCID: PMC10049144 DOI: 10.3390/ijms24065324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/14/2023] [Accepted: 03/07/2023] [Indexed: 03/18/2023] Open
Abstract
Penicillin-binding proteins (PBPs) are considered essential for bacterial peptidoglycan biosynthesis and cell wall assembly. Clavibacter michiganensis is a representative Gram-positive bacterial species that causes bacterial canker in tomato. pbpC plays a significant role in maintaining cell morphological characteristics and stress responses in C. michiganensis. The current study demonstrated that the deletion of pbpC commonly enhances bacterial pathogenicity in C. michiganensis and revealed the mechanisms through which this occurs. The expression of interrelated virulence genes, including celA, xysA, xysB, and pelA, were significantly upregulated in △pbpC mutants. Compared with those in wild-type strains, exoenzyme activities, the formation of biofilm, and the production of exopolysaccharides (EPS) were significantly increased in △pbpC mutants. It is noteworthy that EPS were responsible for the enhancement in bacterial pathogenicity, with the degree of necrotic tomato stem cankers intensifying with the injection of a gradient of EPS from C. michiganensis. These findings highlight new insights into the role of pbpC affecting bacterial pathogenicity, with an emphasis on EPS, advancing the current understanding of phytopathogenic infection strategies for Gram-positive bacteria.
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11
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Draft Genome Sequences of Phytase Active Endophytic and Epiphytic Erwinia gerundensis Isolated from Wheat (Triticum aestivum) Seeds. Microbiol Resour Announc 2023; 12:e0107322. [PMID: 36475734 PMCID: PMC9872571 DOI: 10.1128/mra.01073-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Here, we provide draft genome sequences of an epiphytic strain (HEP01) and an endophytic strain (HEN01) of Erwinia gerundensis, isolated from wheat (Triticum aestivum) seeds. Genome sizes of HEP01 and HEN01 were 3,771,322 bp and 3,750,048 bp, respectively. HEP01 and HEN01 carried one plasmid each with sizes of 565,617 bp and 576,781 bp, respectively. Both showed phenotypic phytase activity.
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12
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Yuan X, Eldred LI, Sundin GW. Exopolysaccharides amylovoran and levan contribute to sliding motility in the fire blight pathogen Erwinia amylovora. Environ Microbiol 2022; 24:4738-4754. [PMID: 36054324 PMCID: PMC9826367 DOI: 10.1111/1462-2920.16193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/31/2022] [Indexed: 01/11/2023]
Abstract
Erwinia amylovora, the causative agent of fire blight, uses flagella-based motilities to translocate to host plant natural openings; however, little is known about how this bacterium migrates systemically in the apoplast. Here, we reveal a novel surface motility mechanism, defined as sliding, in E. amylovora. Deletion of flagella assembly genes did not affect this movement, whereas deletion of biosynthesis genes for the exopolysaccharides (EPSs) amylovoran and levan resulted in non-sliding phenotypes. Since EPS production generates osmotic pressure that potentially powers sliding, we validated this mechanism by demonstrating that water potential positively contributes to sliding. In addition, no sliding was observed when the water potential of the surface was lower than -0.5 MPa. Sliding is a passive motility mechanism. We further show that the force of gravity plays a critical role in directing E. amylovora sliding on unconfined surfaces but has a negligible effect when cells are sliding in confined microcapillaries, in which EPS-dependent osmotic pressure acts as the main force. Although amylovoran and levan are both required for sliding, we demonstrate that they exhibit different roles in bacterial communities. In summary, our study provides fundamental knowledge for a better understanding of mechanisms that drive bacterial sliding motility.
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Affiliation(s)
- Xiaochen Yuan
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - Lauren I. Eldred
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - George W. Sundin
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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13
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De La Fuente L, Merfa MV, Cobine PA, Coleman JJ. Pathogen Adaptation to the Xylem Environment. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:163-186. [PMID: 35472277 DOI: 10.1146/annurev-phyto-021021-041716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A group of aggressive pathogens have evolved to colonize the plant xylem. In this vascular tissue, where water and nutrients are transported from the roots to the rest of the plant, pathogens must be able to thrive under acropetal xylem sap flow and scarcity of nutrients while having direct contact only with predominantly dead cells. Nevertheless, a few bacteria have adapted to exclusively live in the xylem, and various pathogens may colonize other plant niches without causing symptoms unless they reach the xylem. Once established, the pathogens modulate its physicochemical conditions to enhance their growth and virulence. Adaptation to the restrictive lifestyle of the xylem leads to genome reduction in xylem-restricted bacteria, as they have a higher proportion of pseudogenes in their genome. The basis of xylem adaptation is not completely understood; therefore, a need still exists for model systems to advance the knowledge on this topic.
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Affiliation(s)
- Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Jeffrey J Coleman
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA;
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14
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Harding MW, Marques LLR, Allan N, Olson ME, Buziak B, Nadworny P, Omar A, Howard RJ, Feng J. Bactericidal Efficacy of Oxidized Silver against Biofilms Formed by Curtobacterium flaccumfaciens pv. flaccumfaciens. THE PLANT PATHOLOGY JOURNAL 2022; 38:334-344. [PMID: 35953053 PMCID: PMC9372099 DOI: 10.5423/ppj.oa.04.2022.0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 06/11/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
Bacterial wilt is a re-emerging disease on dry bean and can affect many other crop species within the Fabaceae. The causal agent, Curtobacterium flaccumfaciens pv. flaccumfaciens (CFF), is a small, Gram-positive, rodshaped bacterium that is seed-transmitted. Infections in the host become systemic, leading to wilting and economic loss. Clean seed programs and bactericidal seed treatments are two critical management tools. This study characterizes the efficacies of five bactericidal chemicals against CFF. It was hypothesized that this bacterium was capable of forming biofilms, and that the cells within biofilms would be more tolerant to bactericidal treatments. The minimum biocide eradication concentration assay protocol was used to grow CFF biofilms, expose the biofilms to bactericides, and enumerate survivors compared to a non-treated control (water). Streptomycin and oxysilver bisulfate had EC95 values at the lowest concentrations and are likely the best candidates for seed treatment products for controlling seed-borne bacterial wilt of bean. The results showed that CFF formed biofilms during at least two phases of the bacterial wilt disease cycle, and the biofilms were much more difficult to eradicate than their planktonic counterparts. Overall, biofilm formation by CFF is an important part of the bacterial wilt disease cycle in dry edible bean and antibiofilm bactericides such as streptomycin and oxysilver bisulfate may be best suited for use in disease management.
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Affiliation(s)
- Michael W. Harding
- Alberta Agriculture, Forestry and Rural Economic Development, Crop Diversification Centre South, Brooks, AB, T1R 1E6,
Canada
| | | | - Nick Allan
- Chinook Contract Research, Airdrie, AB, T4A 0C3,
Canada
| | | | | | | | - Amin Omar
- Innovotech Inc., Edmonton, AB, T6N 1H1,
Canada
- Department of Pharmaceutical Sciences and Pharmaceutics, Faculty of Pharmacy, Applied Science Private University, Amman,
Jordan
| | | | - Jie Feng
- Alberta Agriculture, Forestry and Rural Economic Development, Alberta Plant Health Lab, Edmonton, Alberta, T5Y 6H3,
Canada
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15
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A complete twelve-gene deletion null mutant reveals that cyclic di-GMP is a global regulator of phase-transition and host colonization in Erwinia amylovora. PLoS Pathog 2022; 18:e1010737. [PMID: 35914003 PMCID: PMC9371280 DOI: 10.1371/journal.ppat.1010737] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 08/11/2022] [Accepted: 07/11/2022] [Indexed: 11/19/2022] Open
Abstract
Cyclic-di-GMP (c-di-GMP) is an essential bacterial second messenger that regulates biofilm formation and pathogenicity. To study the global regulatory effect of individual components of the c-di-GMP metabolic system, we deleted all 12 diguanylate cyclase (dgc) and phosphodiesterase (pde)-encoding genes in E. amylovora Ea1189 (Ea1189Δ12). Ea1189Δ12 was impaired in surface attachment due to a transcriptional dysregulation of the type IV pilus and the flagellar filament. A transcriptomic analysis of surface-exposed WT Ea1189 and Ea1189Δ12 cells indicated that genes involved in metabolism, appendage generation and global transcriptional/post-transcriptional regulation were differentially regulated in Ea1189Δ12. Biofilm formation was regulated by all 5 Dgcs, whereas type III secretion and disease development were differentially regulated by specific Dgcs. A comparative transcriptomic analysis of Ea1189Δ8 (lacks all five enzymatically active dgc and 3 pde genes) against Ea1189Δ8 expressing specific dgcs, revealed the presence of a dual modality of spatial and global regulatory frameworks in the c-di-GMP signaling network.
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16
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Kharadi RR, Sundin GW. CsrD regulates amylovoran biosynthesis and virulence in Erwinia amylovora in a novel cyclic-di-GMP dependent manner. MOLECULAR PLANT PATHOLOGY 2022; 23:1154-1169. [PMID: 35396793 PMCID: PMC9276943 DOI: 10.1111/mpp.13217] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Erwinia amylovora is an economically devastating plant pathogen that causes fire blight disease in members of the Rosaceae family, most notably in apple and pear. The exopolysaccharide amylovoran is a pathogenicity determinant in E. amylovora and a major component of the extracellular matrix of biofilms formed within the xylem vasculature of the host plant. The second messenger cyclic-di-GMP (c-di-GMP) has been reported to positively regulate the transcription of amsG (the first gene in the 12-gene amylovoran [ams] biosynthetic operon), thus impacting amylovoran production. However, the regulatory mechanism by which this interaction occurs is largely unknown. Here, we report that c-di-GMP can bind to specific residues in the EAL domain of the E. amylovora protein CsrD. CsrD and RNase E regulate the degradation of the sRNA CsrB in E. amylovora. When CsrD is bound to c-di-GMP, there is an enhancement in the level of RNase E-mediated degradation of CsrB, which then alters amsG transcription. Additionally, csrD was also found to positively contribute to virulence and biofilm formation. We thus present a pathway of conditional regulation of amylovoran production mediated by changing intracellular levels of c-di-GMP, which impacts disease progression.
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Affiliation(s)
- Roshni R. Kharadi
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - George W. Sundin
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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17
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Albanese D, Cainelli C, Gualandri V, Larger S, Pindo M, Donati C. Genome sequencing provides new insights on the distribution of Erwinia amylovora lineages in northern Italy. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:584-590. [PMID: 35484918 PMCID: PMC9544390 DOI: 10.1111/1758-2229.13074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 06/14/2023]
Abstract
Erwinia amylovora is a Gram-negative bacterium that colonizes a wide variety of plant species causing recurrent local outbreaks of fire blight in crops of the Rosaceae family. Recent genomic surveys have documented the limited genomic diversity of this species, possibly related to a recent evolutionary bottleneck and a strong correlation between geography and phylogenetic structure of the species. Despite its economic importance, little is known about the genetic variability of co-circulating strains during local outbreaks. Here, we report the genome sequences of 82 isolates of E. amylovora, collected from different host plants in a period of 16 years in Trentino, a small region in the Northeastern Italian Alps that has been characterized by recurrent outbreaks of fire blight in apple orchards. While the genome isolated before 2018 are closely related to other strains already present in Europe, we found a novel subclade composed only by isolates that were sampled starting from 2018 and demonstrate that the endemic population of this pathogen can be composed by mixture of strains.
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Affiliation(s)
- Davide Albanese
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
| | - Christian Cainelli
- Center for Technology Transfer, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
| | - Valeria Gualandri
- Center for Technology Transfer, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
- Center of Agriculture, Food and Environment (C3A)University of TrentoTrentoItaly
| | - Simone Larger
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
| | - Massimo Pindo
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
| | - Claudio Donati
- Unit of Computational Biology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1San Michele all'Adige38010Italy
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18
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Schachterle JK, Gdanetz K, Pandya I, Sundin GW. Identification of novel virulence factors in Erwinia amylovora through temporal transcriptomic analysis of infected apple flowers under field conditions. MOLECULAR PLANT PATHOLOGY 2022; 23:855-869. [PMID: 35246928 PMCID: PMC9104256 DOI: 10.1111/mpp.13199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
The enterobacterial pathogen Erwinia amylovora uses multiple virulence-associated traits to cause fire blight, a devastating disease of apple and pear trees. Many virulence-associated phenotypes have been studied that are critical for virulence and pathogenicity. Despite the in vitro testing that has revealed how these systems are transcriptionally regulated, information on when and where in infected tissues these genes are being expressed is lacking. Here, we used a high-throughput sequencing approach to characterize the transcriptome of E. amylovora during disease progression on apple flowers under field infection conditions. We report that type III secretion system genes and flagellar genes are strongly co-expressed. Likewise, genes involved in biosynthesis of the exopolysaccharide amylovoran and sorbitol utilization had similar expression patterns. We further identified a group of 16 genes whose expression is increased and maintained at high levels throughout disease progression across time and tissues. We chose five of these genes for mutational analysis and observed that deletion mutants lacking these genes all display reduced symptom development on apple shoots. Furthermore, these induced genes were over-represented for genes involved in sulphur metabolism and cycling, suggesting the possibility of an important role for maintenance of oxidative homeostasis during apple flower infection.
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Affiliation(s)
- Jeffrey K. Schachterle
- Genetics and Genome Sciences ProgramMichigan State UniversityEast LansingMIUSA
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMIUSA
- Present address:
USDAARS, Cereal Crops Research UnitFargoNDUSA
| | - Kristi Gdanetz
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMIUSA
| | - Ishani Pandya
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMIUSA
| | - George W. Sundin
- Genetics and Genome Sciences ProgramMichigan State UniversityEast LansingMIUSA
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMIUSA
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19
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Xu P, Stirling E, Xie H, Li W, Lv X, Matsumoto H, Cheng H, Xu A, Lai W, Wang Y, Zheng Z, Wang M, Liu X, Ma B, Xu J. Continental scale deciphering of microbiome networks untangles the phyllosphere homeostasis in tea plant. J Adv Res 2022; 44:13-22. [PMID: 36725184 PMCID: PMC9936419 DOI: 10.1016/j.jare.2022.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/21/2022] [Accepted: 04/05/2022] [Indexed: 02/04/2023] Open
Abstract
INTRODUCTION Assembly and co-occurrence of the host co-evolved microbiota are essential ecological and evolutionary processes, which is not only crucial for managing individual plant fitness but also ecological function. However, understanding of the microbiome assembly and co-occurrence in higher plants is not well understood. The tea plant was shown to contribute the forest fitness due to the microbiome assembled in the phyllosphere; the landscape of microbiome assembly in the tea plants and its potential implication on phyllosphere homestasis still remains untangled. OBJECTIVES This study aimed to deciphering of the microbiome networks of the tea plants at a continental scale. It would provide fundamental insights into the factors driving the microbiome assembly, with an extended focus on the resilience towards the potential pathogen in the phyllosphere. METHODS We collected 225 samples from 45 locations spanning approximately 2000-km tea growing regions across China. By integration of high-throughput sequencing data, physicochemical properties profiling and bioinformatics analyses, we investigated continental scale microbiome assembly and co-occurrence in the tea plants. Synthetic assemblages, interaction assay and RT-qPCR were further implemented to analyze the microbial interaction indexed in phyllosphere. RESULTS A trade-off between stochastic and deterministic processes in microbiomes community assembly was highlighted. Assembly processes were dominated by deterministic processes in bulk and rhizosphere soils, and followed by stochastic processes in roots and leaves with amino acids as critical drivers for environmental selection. Sphingobacteria and Proteobacteria ascended from soils to leaves to sustain a core leaf taxa. The core taxa formed a close association with a prevalent foliar pathogen in the co-occurrence network and significantly attenuated the expression of a set of essential virulence genes in pathogen. CONCLUSION Our study unveils the mechanism underpinning microbiome assembly in the tea plants, and a potential implication of the microbiome-mediated resilience framework on the phyllosphere homeostasis.
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Affiliation(s)
- Ping Xu
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Erinne Stirling
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China,Acid Sulfate Soils Centre, School of Biological Sciences, The University of Adelaide, Adelaide 5005, Australia
| | - Hengtong Xie
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Wenbing Li
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, PR China
| | - Xiaofei Lv
- Department of Environmental Engineering, China Jiliang University, Hangzhou 310018, China
| | - Haruna Matsumoto
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, China
| | - Haiyan Cheng
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Anan Xu
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Wanyi Lai
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Yuefei Wang
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Zuntao Zheng
- Institute for the Control of Agrochemicals, Ministry of Agriculture and Rural Affairs, Beijing 100125, China
| | - Mengcen Wang
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Zhejiang University, Hangzhou 310058, China.
| | - Xingmei Liu
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China
| | - Bin Ma
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China; Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China.
| | - Jianming Xu
- College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China
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20
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The RNA-Binding Protein ProQ Impacts Exopolysaccharide Biosynthesis and Second Messenger Cyclic di-GMP Signaling in the Fire Blight Pathogen Erwinia amylovora. Appl Environ Microbiol 2022; 88:e0023922. [PMID: 35416685 DOI: 10.1128/aem.00239-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erwinia amylovora is a plant-pathogenic bacterium that causes fire blight disease in many economically important plants, including apples and pears. This bacterium produces three exopolysaccharides (EPSs), amylovoran, levan, and cellulose, and forms biofilms in host plant vascular tissues, which are crucial for pathogenesis. Here, we demonstrate that ProQ, a conserved bacterial RNA chaperone, was required for the virulence of E. amylovora in apple shoots and for biofilm formation in planta. In vitro experiments revealed that the deletion of proQ increased the production of amylovoran and cellulose. Prc is a putative periplasmic protease, and the prc gene is located adjacent to proQ. We found that Prc and the associated lipoprotein NlpI negatively affected amylovoran production, whereas Spr, a peptidoglycan hydrolase degraded by Prc, positively regulated amylovoran. Since the prc promoter is likely located within proQ, our data showed that proQ deletion significantly reduced the prc mRNA levels. We used a genome-wide transposon mutagenesis experiment to uncover the involvement of the bacterial second messenger c-di-GMP in ProQ-mediated cellulose production. The deletion of proQ resulted in elevated intracellular c-di-GMP levels and cellulose production, which were restored to wild-type levels by deleting genes encoding c-di-GMP biosynthesis enzymes. Moreover, ProQ positively affected the mRNA levels of genes encoding c-di-GMP-degrading phosphodiesterase enzymes via a mechanism independent of mRNA decay. In summary, our study revealed a detailed function of E. amylovora ProQ in coordinating cellulose biosynthesis and, for the first time, linked ProQ with c-di-GMP metabolism and also uncovered a role of Prc in the regulation of amylovoran production. IMPORTANCE Fire blight, caused by the bacterium Erwinia amylovora, is an important disease affecting many rosaceous plants, including apple and pear, that can lead to devastating economic losses worldwide. Similar to many xylem-invading pathogens, E. amylovora forms biofilms that rely on the production of exopolysaccharides (EPSs). In this paper, we identified the RNA-binding protein ProQ as an important virulence regulator. ProQ played a central role in controlling the production of EPSs and participated in the regulation of several conserved bacterial signal transduction pathways, including the second messenger c-di-GMP and the periplasmic protease Prc-mediated systems. Since ProQ has recently been recognized as a global posttranscriptional regulator in many bacteria, these findings provide new insights into multitiered regulatory mechanisms for the precise control of virulence factor production in bacterial pathogens.
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21
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Fontana R, Macchi G, Caproni A, Sicurella M, Buratto M, Salvatori F, Pappadà M, Manfredini S, Baldisserotto A, Marconi P. Control of Erwinia amylovora Growth by Moringa oleifera Leaf Extracts: In Vitro and in Planta Effects. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11070957. [PMID: 35406937 PMCID: PMC9003111 DOI: 10.3390/plants11070957] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/22/2022] [Accepted: 03/29/2022] [Indexed: 06/12/2023]
Abstract
Erwinia amylovora (EA) is a phytopathogenic bacterium, the causative agent of bacterial fire blight, a disease that affects Rosaceaes. In order to replace antibiotics and copper, the antimicrobial activity of three extracts of Moringa oleifera Lam., methanolic (MeOH-MOE), hydroalcoholic (HA-MOE) and hydroalcoholic with maltodextrins (HAMD-MOE), was tested on eleven strains of EA isolated from apple trees by the Emilia-Romagna Phytosanitary Department. MIC and MBC have been evaluated; biofilm formation, swarming motility and amylovoran production were performed with the crystalviolet, soft-agar assay and the amylovoran method. All extracts demonstrated bacteriostatic activity at a concentration of 1 mg/mL, resulting in a 80% reduction in biofilm formation. HAMD-MOE, MeOH-MOE and HA-MOE caused an inhibition of motility of 60%, 65% and 30% after 6 days and a decrease in amylovoran synthesis of 84%, 63% and 93%, respectively. In planta results showed how the compounds were able to inhibit EA virulence on apple trees, mainly if they were applied as a preventive treatment, although the treatment showed a significant reduction in fire blight symptoms progression. The antibacterial activity of the extracts is mainly due to the high concentration of polyphenolic compounds detected in the extracts that was able to alter the permeability of bacterial membrane, resulting in slowing the synthesis of ATP and consequently of all ATP-dependent functions, such as motility and less selectivity towards harmful compounds, which can, thus, enter the cytoplasm and inhibit enzymes involved in replication and quorum sensing. The efficacy, eco-compatibility and low cost make such extracts a potential tool for the control of bacterial fire blight.
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Affiliation(s)
- Riccardo Fontana
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; (G.M.); (A.B.)
| | - Giovanna Macchi
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; (G.M.); (A.B.)
| | - Anna Caproni
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
| | - Mariaconcetta Sicurella
- Department of Environmental Sciences and Prevention, University of Ferrara, 44121 Ferrara, Italy;
| | - Mattia Buratto
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
| | - Francesca Salvatori
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
| | - Mariangela Pappadà
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
| | - Stefano Manfredini
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; (G.M.); (A.B.)
| | - Anna Baldisserotto
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; (G.M.); (A.B.)
| | - Peggy Marconi
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, 44121 Ferrara, Italy; (R.F.); (A.C.); (M.B.); (F.S.); (M.P.)
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22
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Knecht LE, Heinrich N, Born Y, Felder K, Pelludat C, Loessner MJ, Fieseler L. Bacteriophage S6 requires bacterial cellulose for Erwinia amylovora infection. Environ Microbiol 2022; 24:3436-3450. [PMID: 35289468 DOI: 10.1111/1462-2920.15973] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 01/21/2023]
Abstract
Bacteriophages are highly selective in targeting bacteria. This selectivity relies on the specific adsorption of phages to the host cell surface. In this study, a Tn5 transposon mutant library of Erwinia amylovora, the causative agent of fire blight, was screened to identify bacterial receptors required for infection by the podovirus S6. Phage S6 was unable to infect mutants with defects in the bacterial cellulose synthase operon (bcs). The Bcs complex produces and secretes bacterial cellulose, an extracellular polysaccharide associated with bacterial biofilms. Deletion of the bcs operon or associated genes (bcsA, bcsC and bcsZ) verified the crucial role of bacterial cellulose for S6 infection. Application of the cellulose binding dye Congo Red blocked infection by S6. We demonstrate that infective S6 virions degraded cellulose and that Gp95, a phage-encoded cellulase, is involved to catalyse the reaction. In planta S6 did not significantly inhibit fire blight symptom development. Moreover, deletion of bcs genes in E. amylovora did not affect bacterial virulence in blossom infections, indicating that sole application of cellulose targeting phages is less appropriate to biologically control E. amylovora. The interplay between cellulose synthesis, host cell infection and maintenance of the host cell population is discussed.
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Affiliation(s)
- Leandra E Knecht
- Food Microbiology Research Group, Institute of Food and Beverage Innovation, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland.,Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland
| | - Nadine Heinrich
- Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland
| | - Yannick Born
- Food Microbiology Research Group, Institute of Food and Beverage Innovation, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| | - Katja Felder
- Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland
| | - Cosima Pelludat
- Agroscope, Plant Pathology and Zoology in Fruit and Vegetable Production, Wädenswil, Switzerland
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland
| | - Lars Fieseler
- Food Microbiology Research Group, Institute of Food and Beverage Innovation, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
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23
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Aćimović SG, Meredith CL, Santander RD, Khodadadi F. Proof of Concept for Shoot Blight and Fire Blight Canker Management with Postinfection Spray Applications of Prohexadione-Calcium and Acibenzolar- S-Methyl in Apple. PLANT DISEASE 2021; 105:4095-4105. [PMID: 34232052 DOI: 10.1094/pdis-08-20-1744-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
To reduce the severity of shoot blight and prevent the resulting development of cankers on perennial apple wood, we evaluated eight fire blight postinfection spray programs of prohexadione-calcium (PCA) alone or with acibenzolar-S-methyl (ASM) over 2 years. On mature trees of cultivar Royal Court, a single application of the high PCA rate (247 mg/liter) at 2 to 3 days after inoculation resulted in 89.5 and 69.5% reduction of shoot blight severity after inoculation. Two applications of PCA 247 mg/liter 12 or 14 days apart, with the first one applied 2 to 3 days after inoculation, resulted in 78.8 and 74.5% reduction of shoot blight severity in both years. A 100% control of canker incidence on perennial wood from infected shoots in both years was achieved with a single application of PCA (247 mg/liter) applied at 2 or 3 days after the inoculation, and three applications of PCA (125 mg/liter) + ASM (25 mg/liter) 12 to 16 days apart reduced canker incidence by 83.5 and 69% in the 2 years. The other programs with lower PCA rates and frequencies of application reduced shoot blight severity 50.8 and 51.8% (PCA) and 62.6 to 72% and 59.3% (PCA + ASM) over 2 years, respectively. Reduction of canker incidence on wood by the other programs was 66.5% and 69 to 90.4% in the two years, respectively. As fire blight cankers lead to death of dwarf apple trees and serve as primary sources of inoculum, our effective PCA and PCA + ASM programs could serve as viable postinfection management options. These treatments can reduce or prevent canker development and thus significantly abate tree losses in high-density apple orchards after fire blight epidemics occur.
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Affiliation(s)
- Srđan G Aćimović
- Department of Plant Pathology, Physiology, and Weed Science, School of Plant and Environmental Sciences, Alson H. Smith Jr. Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Winchester, VA 22602
| | - Christopher L Meredith
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Sciences, Hudson Valley Research Laboratory, Cornell University, Highland, NY 12528
| | - Ricardo Delgado Santander
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Sciences, Hudson Valley Research Laboratory, Cornell University, Highland, NY 12528
| | - Fatemeh Khodadadi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Sciences, Hudson Valley Research Laboratory, Cornell University, Highland, NY 12528
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Yuan X, McGhee GC, Slack SM, Sundin GW. A Novel Signaling Pathway Connects Thiamine Biosynthesis, Bacterial Respiration, and Production of the Exopolysaccharide Amylovoran in Erwinia amylovora. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1193-1208. [PMID: 34081536 DOI: 10.1094/mpmi-04-21-0095-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Erwinia amylovora is a plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. This bacterium colonizes host vascular tissues via the production of exopolysaccharides (EPSs) including amylovoran. It is well-established that the nearly ubiquitous plasmid pEA29 of E. amylovora is an essential virulence factor, but the underlying mechanism remains uncharacterized. Here, we demonstrated that pEA29 was required for E. amylovora to produce amylovoran and to form a biofilm, and this regulation was dependent on the thiamine biosynthesis operon thiOSGF. We then conducted carbohydrate and genetic analyses demonstrating that the thiamine-mediated effect on amylovoran production was indirect, as cells lacking thiOSGF produced an EPS that did not contain glucuronic acid, one of the key components of amylovoran, whereas the transcriptional activity and RNA levels of the amylovoran biosynthesis genes were not altered. Alternatively, addition of exogenous thiamine restored amylovoran production in the pEA29-cured strain of E. amylovora and positively impacted amylovoran production in a dose-dependent manner. Individual deletion of several chromosomal thiamine biosynthesis genes also affected amylovoran production, implying that a complete thiamine biosynthesis pathway is required for the thiamine-mediated effect on amylovoran production in E. amylovora. Finally, we determined that an imbalanced tricarboxylic acid cycle negatively affected amylovoran production, which was restored by addition of exogenous thiamine or overexpression of the thiOSGF operon. In summary, our report revealed a novel signaling pathway that impacts E. amylovora virulence in which thiamine biosynthesis enhances bacterial respiration that provides energetic requirements for the biosynthesis of EPS amylovoran.[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)
- Xiaochen Yuan
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Gayle C McGhee
- United States Department of Agriculture, Agriculture Research Service, Horticultural Crops Research Laboratory, Corvallis, OR 97330, U.S.A
| | - Suzanne M Slack
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - George W Sundin
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
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Kharadi RR, Schachterle JK, Yuan X, Castiblanco LF, Peng J, Slack SM, Zeng Q, Sundin GW. Genetic Dissection of the Erwinia amylovora Disease Cycle. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:191-212. [PMID: 33945696 DOI: 10.1146/annurev-phyto-020620-095540] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fire blight, caused by the bacterial phytopathogen Erwinia amylovora, is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an E. amylovora infection in the host. We discuss the key aspects of type III secretion-mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components. We present an overall outlook on the genetic elements contributing to E. amylovora pathogenesis, including an exploration of the impact of floral microbiomes on E. amylovora colonization, and summarize the current knowledge of host responses to an incursion and how this response stimulates further infection and systemic spread. We hope to facilitate the identification of new, unexplored areas of research in this pathosystem that can help identify evolutionarily susceptible genetic targets to ultimately aid in the design of sustainable strategies for fire blight disease mitigation.
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Affiliation(s)
- Roshni R Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jeffrey K Schachterle
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
- Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, Beltsville, Maryland 20705, USA
| | - Xiaochen Yuan
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Luisa F Castiblanco
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jingyu Peng
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Suzanne M Slack
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Quan Zeng
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
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26
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Kim SH, Cho G, Lee SI, Kim DR, Kwak YS. Comparison of Bacterial Community of Healthy and Erwinia amylovora Infected Apples. THE PLANT PATHOLOGY JOURNAL 2021; 37:396-403. [PMID: 34365751 PMCID: PMC8357565 DOI: 10.5423/ppj.nt.04.2021.0062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 05/17/2021] [Indexed: 06/01/2023]
Abstract
Fire blight disease, caused by Erwinia amylovora, could damage rosaceous plants such as apples, pears, and raspberries. In this study, we designed to understand how E. amylovora affected other bacterial communities on apple rhizosphere; twig and fruit endosphere; and leaf, and fruit episphere. Limited studies on the understanding of the microbial community of apples and changes the community structure by occurrence of the fire blight disease were conducted. As result of these experiments, the infected trees had low species richness and operational taxonomic unit diversity when compared to healthy trees. Rhizospheric bacterial communities were stable regardless of infection. But the communities in endosphere and episphere were significanlty affected by E. amylovora infection. We also found that several metabolic pathways differ significantly between infected and healthy trees. In particular, we observed differences in sugar metabolites. The finding provides that sucrose metabolites are important for colonization of E. amylovora in host tissue. Our results provide fundamental information on the microbial community structures between E. amylovora infected and uninfected trees, which will contribute to developing novel control strategies for the fire blight disease.
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Affiliation(s)
- Su-Hyeon Kim
- Division of Applied Life Science (BK21Plus) and Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea
| | - Gyoengjun Cho
- Division of Applied Life Science (BK21Plus) and Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea
| | - Su In Lee
- Department of Plant Medicine, Institute of Agriculture & Life Science, Gyeongsang National University, Jinju 52828, Korea
| | - Da-Ran Kim
- Division of Applied Life Science (BK21Plus) and Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea
| | - Youn-Sig Kwak
- Division of Applied Life Science (BK21Plus) and Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea
- Department of Plant Medicine, Institute of Agriculture & Life Science, Gyeongsang National University, Jinju 52828, Korea
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27
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Peil A, Emeriewen OF, Khan A, Kostick S, Malnoy M. Status of fire blight resistance breeding in Malus. JOURNAL OF PLANT PATHOLOGY 2021; 103:3-12. [PMID: 0 DOI: 10.1007/s42161-020-00581-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/21/2020] [Indexed: 05/20/2023]
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28
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Zayed A, Mansour MK, Sedeek MS, Habib MH, Ulber R, Farag MA. Rediscovering bacterial exopolysaccharides of terrestrial and marine origins: novel insights on their distribution, biosynthesis, biotechnological production, and future perspectives. Crit Rev Biotechnol 2021; 42:597-617. [PMID: 34320886 DOI: 10.1080/07388551.2021.1942779] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Bacteria exist in colonies as aggregates or associated with surfaces forming biofilms rather than planktonic cells. Living in such a unique manner is always mediated via a matrix of extracellular polymeric substances, which are composed mainly of polysaccharides or specifically exopolysaccharides (EPS). Biofilm formation and hence EPS production are affected by biotic and abiotic factors inducing/inhibiting several involved genes and other molecules. In addition, various aspects of bacterial EPS regarding: physiological functions, molecular weight, and chemical composition were demonstrated. Recent investigations have revealed a wide spectrum of EPS chemical and physicochemical properties showing promising applications in different industrial sectors. For instance, lactic acid bacteria (LAB)- and marine-derived EPS exhibit: immunomodulatory, antioxidant, antitumor, bioremediation of heavy metals, as well as thickening and viscosity modifiers in the food industry. However, bacterial EPS have not yet been commercially implemented, in contrast to plant-derived analogues. The current review aims to rediscover the EPS structural and biosynthetic features derived from marine and terrestrial bacteria, and applications as well.
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Affiliation(s)
- Ahmed Zayed
- Pharmacognosy Department, College of Pharmacy, Tanta University, Tanta, Egypt.,Institute of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Mai K Mansour
- Department of Medicinal Plants and Natural Products, National Organization for Drug Control and Research, Giza, Egypt
| | - Mohamed S Sedeek
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Egypt
| | - Mohamed H Habib
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Roland Ulber
- Institute of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Mohamed A Farag
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Egypt.,Chemistry Department, School of Sciences and Engineering, The American University in Cairo, New Cairo, Egypt
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29
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Bible AN, Chang M, Morrell-Falvey JL. Identification of a diguanylate cyclase expressed in the presence of plants and its application for discovering candidate gene products involved in plant colonization by Pantoea sp. YR343. PLoS One 2021; 16:e0248607. [PMID: 34288916 PMCID: PMC8294551 DOI: 10.1371/journal.pone.0248607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/01/2021] [Indexed: 12/03/2022] Open
Abstract
Microbial colonization of plant roots is a highly complex process that requires the coordination and regulation of many gene networks, yet the identities and functions of many of these gene products have yet to be discovered. Pantoea sp. YR343, a gamma-proteobacterium isolated from the rhizosphere of Populus deltoides, forms robust biofilms along the root surfaces of Populus and possesses plant growth-promoting characteristics. In this work, we identified three diguanylate cyclases in the plant-associated microbe Pantoea sp. YR343 that are expressed in the presence of plant roots. One of these diguanylate cyclases, DGC2884, localizes to discrete sites in the cells and its overexpression results in reduced motility and increased EPS production and biofilm formation. We performed a genetic screen by expressing this diguanylate cyclase from an inducible promoter in order to identify candidate gene products that may be involved in root colonization by Pantoea sp. YR343. Further, we demonstrate the importance of other domains in DGC2884 to its activity, which in combination with the genes identified by transposon mutagenesis, may yield insights into the mechanisms of plant association as well as the activity and regulation of homologous enzymes in medically and agriculturally relevant microbes.
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Affiliation(s)
- Amber N. Bible
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
| | - Mang Chang
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, United States of America
| | - Jennifer L. Morrell-Falvey
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States of America
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, United States of America
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30
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Ya'ar Bar S, Dor S, Erov M, Afriat-Jurnou L. Identification and Characterization of a New Quorum-Quenching N-acyl Homoserine Lactonase in the Plant Pathogen Erwinia amylovora. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:5652-5662. [PMID: 33974427 DOI: 10.1021/acs.jafc.1c00366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Quorum quenching (QQ) is the ability to interfere with bacterial cell to cell communication, known as quorum sensing (QS). QQ enzymes that degrade or modify acyl homoserine lactones (AHLs) have been attracting increasing interest as promising agents for inhibiting QS-mediated bacterial pathogenicity. Plant pathogens from the genus Erwinia cause diseases in several economically important crops. Fire blight is a devastating plant disease caused by Erwinia amylovora, affecting a wide range of host species within the Rosaceae and posing a major global threat for commercial apple and pear production. While QS has been described in Erwinia species, no AHL-degrading enzymes were identified and characterized. Here, phylogenetic analysis and structural modeling were applied to identify an AHL lactonase in E. amylovora (dubbed EaAiiA). Following recombinant expression and purification, the enzyme was biochemically characterized. EaAiiA lactonase activity was dependent on metal ions and effectively degraded AHLs with high catalytic efficiency. Its highest specific activity (kcat/KM value) was observed against one of the AHLs (3-oxo-C6-homoserine lactone) secreted from E. amylovora. Exogenous addition of the purified enzyme to cultures of E. amylovora reduced the formation of levan, a QS-regulated virulence factor, by 40% and the transcription level of the levansucrase-encoding gene by 55%. Furthermore, preincubation of E. amylovora cultures with EaAiiA inhibited the progress of fire blight symptoms in immature Pyrus communis fruits. These results demonstrate the ability of the identified enzyme from E. amylovora to act as a quorum-quenching lactonase.
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Affiliation(s)
- Sapir Ya'ar Bar
- Migal-Galilee Research Institute, Kiryat Shmona 11016, Israel
- Faculty of Sciences and Technology, Tel-Hai Academic College, Upper Galilee 1220800, Israel
| | - Shlomit Dor
- Migal-Galilee Research Institute, Kiryat Shmona 11016, Israel
| | - Mayan Erov
- Migal-Galilee Research Institute, Kiryat Shmona 11016, Israel
| | - Livnat Afriat-Jurnou
- Migal-Galilee Research Institute, Kiryat Shmona 11016, Israel
- Faculty of Sciences and Technology, Tel-Hai Academic College, Upper Galilee 1220800, Israel
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31
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Mendes RJ, Luz JP, Santos C, Tavares F. CRISPR genotyping as complementary tool for epidemiological surveillance of Erwinia amylovora outbreaks. PLoS One 2021; 16:e0250280. [PMID: 33861806 PMCID: PMC8051791 DOI: 10.1371/journal.pone.0250280] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/02/2021] [Indexed: 12/12/2022] Open
Abstract
Fire blight is a destructive plant disease caused by Erwinia amylovora affecting pome fruit trees, and responsible for large yield declines, long phytosanitary confinements, and high economic losses. In Portugal, the first major fire blight outbreaks occurred in 2010 and 2011, and although later considered eradicated, the emergence of other outbreaks in recent years stressed the need to characterize the E. amylovora populations associated with these outbreaks. In this regard, CRISPR genotyping, assessment of three virulence markers, and semi-quantitative virulence bioassays, were carried out to determine the genotype, and assess the virulence of thirty-six E. amylovora isolates associated with outbreaks occurring between 2010 and 2017 and affecting apple and pear orchards located in the country central-west, known as the main producing region of pome fruits in Portugal. The data gathered reveal that 35 E. amylovora isolates belong to one of the widely-distributed CRISPR genotypes (5-24-38 / D-a-α) regardless the host species, year and region. Ea 680 was the single isolate revealing a new CRISPR genotype due to a novel CR2 spacer located closer to the leader sequence and therefore thought to be recently acquired. Regarding pathogenicity, although dot-blot hybridization assays showed the presence of key virulence factors, namely hrpL (T3SS), hrpN (T3E) and amsG from the amylovoran biosynthesis operon in all E. amylovora isolates studied, pathogenicity bioassays on immature pear slices allowed to distinguish four virulence levels, with most of the isolates revealing an intermediate to severe virulence phenotype. Regardless the clonal population structure of the E. amylovora associated to the outbreaks occurring in Portugal between 2010 and 2017, the different virulence phenotypes, suggests that E. amylovora may have been introduced at different instances into the country. This is the first study regarding E. amylovora in Portugal, and it discloses a novel CRISPR genotype for this bacterium.
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Affiliation(s)
- Rafael J. Mendes
- Faculty of Sciences of University of Porto, Porto, Portugal
- LAQV/REQUIMTE, Faculty of Sciences of University of Porto, Porto, Portugal
- CITAB—Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- CIBIO–Research Centre in Biodiversity and Genetic Resources, InBIO, Associated Laboratory, University of Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - João Pedro Luz
- QRural, Polytechnic Institute of Castelo Branco, School of Agriculture, Castelo Branco, Portugal
| | - Conceição Santos
- Faculty of Sciences of University of Porto, Porto, Portugal
- LAQV/REQUIMTE, Faculty of Sciences of University of Porto, Porto, Portugal
| | - Fernando Tavares
- Faculty of Sciences of University of Porto, Porto, Portugal
- CIBIO–Research Centre in Biodiversity and Genetic Resources, InBIO, Associated Laboratory, University of Porto, Campus Agrário de Vairão, Vairão, Portugal
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The Immunomodulatory Properties of β-2,6 Fructans: A Comprehensive Review. Nutrients 2021; 13:nu13041309. [PMID: 33921025 PMCID: PMC8071392 DOI: 10.3390/nu13041309] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/05/2021] [Accepted: 04/11/2021] [Indexed: 02/07/2023] Open
Abstract
Polysaccharides such as β-2,1-linked fructans including inulin or fructose oligosaccharides are well-known prebiotics with recognised immunomodulatory properties. In recent years, other fructan types covering β-2,6-linked fructans, particularly microbial levans, have gained increasing interest in the field. β-2,6-linked fructans of different degrees of polymerisation can be synthesised by plants or microbes including those that reside in the gastrointestinal tract. Accumulating evidence suggests a role for these β-2,6 fructans in modulating immune function. Here, we provide an overview of the sources and structures of β-2,6 fructans from plants and microbes and describe their ability to modulate immune function in vitro and in vivo along with the suggested mechanisms underpinning their immunomodulatory properties. Further, we discuss the limitations and perspectives pertinent to current studies and the potential applications of β-2,6 fructans including in gut health.
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33
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Beyond the Wall: Exopolysaccharides in the Biofilm Lifestyle of Pathogenic and Beneficial Plant-Associated Pseudomonas. Microorganisms 2021; 9:microorganisms9020445. [PMID: 33670010 PMCID: PMC7926942 DOI: 10.3390/microorganisms9020445] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/12/2021] [Accepted: 02/18/2021] [Indexed: 11/16/2022] Open
Abstract
The formation of biofilms results from a multicellular mode of growth, in which bacteria remain enwrapped by an extracellular matrix of their own production. Many different bacteria form biofilms, but among the most studied species are those that belong to the Pseudomonas genus due to the metabolic versatility, ubiquity, and ecological significance of members of this group of microorganisms. Within the Pseudomonas genus, biofilm studies have mainly focused on the opportunistic human pathogen Pseudomonas aeruginosa due to its clinical importance. The extracellular matrix of P. aeruginosa is mainly composed of exopolysaccharides, which have been shown to be important for the biofilm architecture and pathogenic features of this bacterium. Notably, some of the exopolysaccharides recurrently used by P. aeruginosa during biofilm formation, such as the alginate and polysaccharide synthesis loci (Psl) polysaccharides, are also used by pathogenic and beneficial plant-associated Pseudomonas during their interaction with plants. Interestingly, their functions are multifaceted and seem to be highly dependent on the bacterial lifestyle and genetic context of production. This paper reviews the functions and significance of the exopolysaccharides produced by plant-associated Pseudomonas, particularly the alginate, Psl, and cellulose polysaccharides, focusing on their equivalents produced in P. aeruginosa within the context of pathogenic and beneficial interactions.
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34
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Boucher M, Collins R, Hesler S, Cox K, Loeb G. The Effect of Erwinia amylovora Infection in Apple Saplings and Fruit on the Behavior of Delia platura (Diptera: Anthomyiidae). ENVIRONMENTAL ENTOMOLOGY 2021; 50:117-125. [PMID: 33290563 DOI: 10.1093/ee/nvaa153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Indexed: 06/12/2023]
Abstract
The Vector Manipulation Hypothesis (VMH) posits that phytopathogens develop strategies to enhance dissemination by mediating behavior change in insect vectors. The VMH is poorly studied in phytopathogenic bacteria, especially in systems with numerous, occasional vectors. Erwinia amylovora is a bacterial pathogen of pome fruit that produces a bacterial ooze and is mechanically vectored by insects after they feed on ooze. The blossom blight phase of the disease exhibits manipulation of honeybees, leading to enhanced transmission, but whether the same occurs during the shoot blight phase of the disease is unknown. The goal of this study was to evaluate the effect of E. amylovora on the behavior of Delia platura, a fly with a worldwide endemic presence that may transmit E. amylovora. We show that D. platura prefer infected, oozing fruit to uninfected fruit in choice tests and that preference subsides when bacterial ooze is removed from the infected fruit. Flies did not exhibit a preference between infected saplings and uninfected saplings. The volatiles of infected fruit did not attract D. platura, indicating that diseased fruit odor is not responsible for the observed preference for infected fruit. Flies did not differentiate between sapling odors until infected trees had died, at which point they preferred uninfected tree odors. This study supports previous hypotheses suggesting that E. amylovora takes advantage of existing plant-insect interactions, though it is not fully understood how significantly behavioral changes affect transmission. Additional pathosystems with occasional, nonspecific vectors should be studied to further understanding of the VMH.
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Affiliation(s)
- Matthew Boucher
- Department of Entomology, Cornell AgriTech, New York State Agricultural Experiment Station, Cornell University, Geneva, NY
| | - Rowan Collins
- Department of Entomology, Cornell AgriTech, New York State Agricultural Experiment Station, Cornell University, Geneva, NY
| | - Stephen Hesler
- Department of Entomology, Cornell AgriTech, New York State Agricultural Experiment Station, Cornell University, Geneva, NY
| | - Kerik Cox
- Section of Plant Pathology and Plant Microbe Biology, School of Integrated Plant Sciences, Cornell AgriTech, New York State Agricultural Experiment Station, Geneva, NY
| | - Greg Loeb
- Department of Entomology, Cornell AgriTech, New York State Agricultural Experiment Station, Cornell University, Geneva, NY
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35
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Kırtel O, Aydın H, Toksoy Öner E. Fructanogenic traits in halotolerant Bacillus licheniformis OK12 and their predicted functional significance. J Appl Microbiol 2021; 131:1391-1404. [PMID: 33484024 DOI: 10.1111/jam.15015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 01/26/2023]
Abstract
AIMS Isolating a novel bacterial source of fructan from a saltern and analysis of its genome to better understand the possible roles of fructans in hypersaline environments. METHODS AND RESULTS Bacteria were isolated from crude salt samples originating from Çamaltı Saltern in Western Turkey and screened for fructanogenic traits in high-salt and sucrose-rich selective medium. Exopolysaccharide accumulated in the presence of sucrose by isolate OK12 was purified and chemically characterized via HPLC, FT-IR and NMR, which revealed that it was a levan-type fructan (β-2,6 linked homopolymer of fructose). The isolate was taxonomically classified as Bacillus licheniformis OK12 through 16S rRNA gene and whole-genome sequencing methods. Strain OK12 harbours one levansucrase and two different levanase genes, which altogether were predicted to significantly contribute to intracellular glucose and fructose pools. The isolate could withstand 15% NaCl, and thus classified as a halotolerant. CONCLUSIONS Fructanogenic traits in halotolerant B. licheniformis OK12 are significant due to predicted influx of glucose and fructose as a result of levan biosynthesis and levan hydrolysis, respectively. SIGNIFICANCE AND IMPACT OF THE STUDY Fructans from the residents of hypersaline habitats are underexplored compounds and are expected to demonstrate physicochemical properties different from their non-halophilic counterparts. Revealing fructanogenic traits in the genome of a halotolerant bacterium brings up a new perspective in physiological roles of fructans.
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Affiliation(s)
- O Kırtel
- Industrial Biotechnology and Systems Biology Research Group-IBSB, Bioengineering Department, Göztepe Campus, Marmara University, Istanbul, Turkey
| | - H Aydın
- Industrial Biotechnology and Systems Biology Research Group-IBSB, Bioengineering Department, Göztepe Campus, Marmara University, Istanbul, Turkey
| | - E Toksoy Öner
- Industrial Biotechnology and Systems Biology Research Group-IBSB, Bioengineering Department, Göztepe Campus, Marmara University, Istanbul, Turkey
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36
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Peng J, Schachterle JK, Sundin GW. Orchestration of virulence factor expression and modulation of biofilm dispersal in Erwinia amylovora through activation of the Hfq-dependent small RNA RprA. MOLECULAR PLANT PATHOLOGY 2021; 22:255-270. [PMID: 33314618 PMCID: PMC7814967 DOI: 10.1111/mpp.13024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 06/12/2023]
Abstract
Erwinia amylovora is the causative agent of the devastating disease fire blight of pome fruit trees. After infection of host plant leaves at apple shoot tips, E. amylovora cells form biofilms in xylem vessels, restrict water flow, and cause wilting symptoms. Although E. amylovora is well known to be able to cause systemic infection, how biofilm cells of E. amylovora transit from the sessile mode of growth in xylem to the planktonic mode of growth in cortical parenchyma remains unknown. Increasing evidence has suggested the important modulatory roles of Hfq-dependent small RNAs (sRNAs) in the pathogenesis of E. amylovora. Here, we demonstrate that the sRNA RprA acts as a positive regulator of amylovoran exopolysaccharide production, the type III secretion system (T3SS), and flagellar-dependent motility, and as a negative regulator of levansucrase activity and cellulose production. We also show that RprA affects the promoter activity of multiple virulence factor genes and regulates hrpS, a critical T3SS regulator, at the posttranscriptional level. We determined that rprA expression can be activated by the Rcs phosphorelay, and that expression is active during T3SS-mediated host infection in an immature pear fruit infection model. We further showed that overexpression of rprA activated the in vitro dispersal of E. amylovora cells from biofilms. Thus, our investigation of the varied role of RprA in affecting E. amylovora virulence provides important insights into the functions of this sRNA in biofilm control and systemic infection.
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Affiliation(s)
- Jingyu Peng
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - Jeffrey K. Schachterle
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
- Present address:
US National Arboretum – Floral and Nursery Plants Research UnitUSDA‐ARSBeltsvilleMarylandUSA
| | - George W. Sundin
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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Schmid J, Wefers D, Vogel RF, Jakob F. Analysis of Structural and Functional Differences of Glucans Produced by the Natively Released Dextransucrase of Liquorilactobacillus hordei TMW 1.1822. Appl Biochem Biotechnol 2021; 193:96-110. [PMID: 32820351 PMCID: PMC7790797 DOI: 10.1007/s12010-020-03407-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/12/2020] [Indexed: 11/26/2022]
Abstract
The properties of the glucopolymer dextran are versatile and linked to its molecular size, structure, branching, and secondary structure. However, suited strategies to control and exploit the variable structures of dextrans are scarce. The aim of this study was to delineate structural and functional differences of dextrans, which were produced in buffers at different conditions using the native dextransucrase released by Liquorilactobacillus (L.) hordei TMW 1.1822. Rheological measurements revealed that dextran produced at pH 4.0 (MW = 1.1 * 108 Da) exhibited the properties of a viscoelastic fluid up to concentrations of 10% (w/v). By contrast, dextran produced at pH 5.5 (MW = 1.86 * 108 Da) was gel-forming already at 7.5% (w/v). As both dextrans exhibited comparable molecular structures, the molecular weight primarily influenced their rheological properties. The addition of maltose to the production assays caused the formation of the trisaccharide panose instead of dextran. Moreover, pre-cultures of L. hordei TMW 1.1822 grown without sucrose were substantial for recovery of higher dextran yields, since the cells stored the constitutively expressed dextransucrase intracellularly, until sucrose became available. These findings can be exploited for the controlled recovery of functionally diverse dextrans and oligosaccharides by the use of one dextransucrase type.
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Affiliation(s)
- Jonas Schmid
- Chair of Technical Microbiology, Technical University of Munich (TUM), Freising, Germany
| | - Daniel Wefers
- Division of Food Chemistry, Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
- Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Rudi F Vogel
- Chair of Technical Microbiology, Technical University of Munich (TUM), Freising, Germany
| | - Frank Jakob
- Chair of Technical Microbiology, Technical University of Munich (TUM), Freising, Germany.
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38
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The Union Is Strength: The Synergic Action of Long Fatty Acids and a Bacteriophage against Xanthomonas campestris Biofilm. Microorganisms 2020; 9:microorganisms9010060. [PMID: 33379305 PMCID: PMC7824728 DOI: 10.3390/microorganisms9010060] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/19/2020] [Accepted: 12/23/2020] [Indexed: 12/24/2022] Open
Abstract
Xanthomonas campestris pv. campestris is known as the causative agent of black rot disease, which attacks mainly crucifers, severely lowering their global productivity. One of the main virulence factors of this pathogen is its capability to penetrate and form biofilm structures in the xylem vessels. The discovery of novel approaches to crop disease management is urgent and a possible treatment could be aimed at the eradication of biofilm, although anti-biofilm approaches in agricultural microbiology are still rare. Considering the multifactorial nature of biofilm, an effective approach against Xanthomonas campestris implies the use of a multi-targeted or combinatorial strategy. In this paper, an anti-biofilm strategy based on the use of fatty acids and the bacteriophage (Xccφ1)-hydroxyapatite complex was optimized against Xanthomonas campestris mature biofilm. The synergic action of these elements was demonstrated and the efficient removal of Xanthomonas campestris mature biofilm was also proven in a flow cell system, making the proposed approach an effective solution to enhance plant survival in Xanthomonas campestris infections. Moreover, the molecular mechanisms responsible for the efficacy of the proposed treatment were explored.
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39
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Kharadi RR, Sundin GW. Cyclic-di-GMP Regulates Autoaggregation Through the Putative Peptidoglycan Hydrolase, EagA, and Regulates Transcription of the znuABC Zinc Uptake Gene Cluster in Erwinia amylovora. Front Microbiol 2020; 11:605265. [PMID: 33281804 PMCID: PMC7705223 DOI: 10.3389/fmicb.2020.605265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/27/2020] [Indexed: 11/24/2022] Open
Abstract
Erwinia amylovora is the causal agent of fire blight, an economically impactful disease that affects apple and pear production worldwide. E. amylovora pathogenesis is comprised of distinct type III secretion-dependent and biofilm-dependent stages. Alterations in the intracellular levels of cyclic-di-GMP (c-di-GMP) regulate the transition between the different stages of infection in E. amylovora. We previously reported that hyper-elevation of c-di-GMP levels in E. amylovora Ea1189, resulting from the deletion of all three c-di-GMP specific phosphodiesterase genes (Ea1189ΔpdeABC), resulted in an autoaggregation phenotype. The two major exopolysaccharides, amylovoran and cellulose, were also shown to partially contribute to autoaggregation. In this study, we aimed to identify the c-di-GMP dependent factor(s) that contributes to autoaggregation. We conducted a transposon mutant screen in Ea1189ΔpdeABC and selected for loss of autoaggregation. Our search identified a peptidoglycan hydrolase, specifically, a D, D-endopeptidase of the metallopeptidase class, EagA (Erwiniaaggregation factor A), that was found to physiologically contribute to autoaggregation in a c-di-GMP dependent manner. The production of amylovoran was also positively affected by EagA levels. An eagA deletion mutant (Ea1189ΔeagA) was significantly reduced in virulence compared to the wild type E. amylovora Ea1189. eagA is part of the znuABC zinc uptake gene cluster and is located within an operon downstream of znuA. The znuAeagA/znuCB gene cluster was transcriptionally regulated by elevated levels of c-di-GMP as well as by the zinc-dependent transcriptional repressor Zur. We also observed that with an influx of Zn2+ in the environment, the transcription of the znuAeagA/znuBC gene cluster is regulated by both Zur and a yet to be characterized c-di-GMP dependent pathway.
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Affiliation(s)
- Roshni R Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
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40
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Santander RD, Català-Senent JF, Figàs-Segura À, Biosca EG. From the roots to the stem: unveiling pear root colonization and infection pathways by Erwinia amylovora. FEMS Microbiol Ecol 2020; 96:5920614. [PMID: 33038244 DOI: 10.1093/femsec/fiaa210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/08/2020] [Indexed: 01/11/2023] Open
Abstract
Fire blight caused by Erwinia amylovora affects pome fruit worldwide, generating serious economic losses. Despite the abundant literature on E. amylovora infection mechanisms of aerial plant organs, root infection routes remain virtually unexplored. Assessing these infection pathways is necessary for a full understanding of the pathogen's ecology. Using the pathosystem Pyrus communis-E. amylovora and different experimental approaches including a green fluorescent protein transformant (GFP1) and epifluorescence microscopy (EFM) and laser confocal scanning microscopy (LCSM), we demonstrated the pathogen's ability to infect, colonize and invade pear roots and cause characteristic fire blight symptoms both in the aerial part and in the root system. Plant infections after soil irrigation with E. amylovora-contaminated water were favored by root damage, which agreed with EFM and LCSM observations. E. amylovora GFP1 cells formed aggregates/biofilms on root surfaces and invaded the cortex through wounds and sites of lateral root emergence. Sugars, sugar-alcohols and amino acids typically secreted by roots, favored the in vitro biofilm development by E. amylovora. Migration of E. amylovora cells to aerial tissues mainly occurred after xylem penetration. Overall, our findings revealed, for the first time, common root infection patterns between E. amylovora and well-known soil borne plant pathogens and endophytes.
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Affiliation(s)
- Ricardo D Santander
- Department of Microbiology and Ecology, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
| | - José F Català-Senent
- Department of Microbiology and Ecology, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
| | - Àngela Figàs-Segura
- Department of Microbiology and Ecology, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
| | - Elena G Biosca
- Department of Microbiology and Ecology, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
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41
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Zhang WB, Yan HL, Zhu ZC, Zhang C, Du PX, Zhao WJ, Li WM. Genome-wide identification of the Sec-dependent secretory protease genes in Erwinia amylovora and analysis of their expression during infection of immature pear fruit. J Zhejiang Univ Sci B 2020; 21:716-726. [PMID: 32893528 DOI: 10.1631/jzus.b2000281] [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] [Indexed: 01/08/2023]
Abstract
The general secretory (Sec) pathway represents a common mechanism by which bacteria secrete proteins, including virulence factors, into the extracytoplasmic milieu. However, there is little information about this system, as well as its associated secretory proteins, in relation to the fire blight pathogen Erwinia amylovora. In this study, data mining revealed that E. amylovora harbors all of the essential components of the Sec system. Based on this information, we identified putative Sec-dependent secretory proteases in E. amylovora on a genome-wide scale. Using the programs SignalP, LipoP, and Phobius, a total of 15 putative proteases were predicted to contain the N-terminal signal peptides (SPs) that might link them to the Sec-dependent pathway. The activities of the predicted SPs were further validated using an Escherichia coli-based alkaline phosphatase (PhoA) gene fusion system that confirmed their extracytoplasmic property. Transcriptional analyses showed that the expression of 11 of the 15 extracytoplasmic protease genes increased significantly when E. amylovora was used to inoculate immature pears, suggesting their potential roles in plant infection. The results of this study support the suggestion that E. amylovora might employ the Sec system to secrete a suite of proteases to enable successful infection of plants, and shed new light on the interaction of E. amylovora with host plants.
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Affiliation(s)
- Wang-Bin Zhang
- College of Plant Science, Tarim University, Alar 843300, China.,Southern Xinjiang Key Laboratory of Integrated Pest Management, Tarim University, Alar 843300, China
| | - Hai-Lin Yan
- College of Plant Science, Tarim University, Alar 843300, China.,Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zong-Cai Zhu
- College of Plant Science, Tarim University, Alar 843300, China.,Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chao Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Pei-Xiu Du
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wen-Jun Zhao
- Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Wei-Min Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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42
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Pontes JGDM, Fernandes LS, Dos Santos RV, Tasic L, Fill TP. Virulence Factors in the Phytopathogen-Host Interactions: An Overview. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:7555-7570. [PMID: 32559375 DOI: 10.1021/acs.jafc.0c02389] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phytopathogens are responsible for great losses in agriculture, once they are able to subvert or elude the host defense mechanisms through virulence factors secretion for their dissemination. Herein, it is reviewed phytotoxins that act as virulence factors and are produced by bacterial phytopathogens (Candidatus Liberibacter spp., Erwinia amylovora, Pseudomonas syringae pvs and Xanthomonas spp.) and fungi (Alternaria alternata, Botrytis cinerea, Cochliobolus spp., Fusarium spp., Magnaporthe spp., and Penicillium spp.), which were selected in accordance to their worldwide importance due to the biochemical and economical aspects. In the current review, it is sought to understand the role of virulence factors in the pathogen-host interactions that result in plant diseases.
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Affiliation(s)
| | - Laura Soler Fernandes
- Laboratório de Biologia Quı́mica Microbiana (LaBioQuiMi), IQ-UNICAMP, Campinas, SP, Brazil
| | | | - Ljubica Tasic
- Laboratório de Quı́mica Biológica (LQB), IQ-UNICAMP, Campinas, SP, Brazil
| | - Taicia Pacheco Fill
- Laboratório de Biologia Quı́mica Microbiana (LaBioQuiMi), IQ-UNICAMP, Campinas, SP, Brazil
- Institute of Chemistry, Universidade Estadual de Campinas (UNICAMP), P.O. Box 6154, 13083970 Campinas, SP, Brazil
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43
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Huang X, Luo W, Wu S, Long Y, Li R, Zheng F, Greiner S, Rausch T, Zhao H. Apoplastic maize fructan exohydrolase Zm-6-FEH displays substrate specificity for levan and is induced by exposure to levan-producing bacteria. Int J Biol Macromol 2020; 163:630-639. [PMID: 32622772 DOI: 10.1016/j.ijbiomac.2020.06.254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 06/14/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023]
Abstract
Fructan exohydrolases (FEHs) are structurally related to cell wall invertases. While the latter are ubiquitous in higher plants, the role of FEHs in non-fructan species has remained enigmatic. To explore possible roles of FEHs in maize, a full length putative Zm-6-FEH-encoding cDNA was cloned displaying high sequence similarity with cell wall invertases. For functional characterization, Zm-6-FEH protein was expressed in Picha pastoris and in Nicotiana benthamiana leaves. Enzyme activity of recombinant Zm-6-FEH protein showed a strong preference for levan as substrate. Expression profiling in maize seedlings revealed higher transcript amounts in the more mature leaf parts as compared to the growth zone at the base of the leaf, in good correlation with FEH enzyme activities. Subcellular localization analysis indicated Zm-6-FEH location in the apoplast. Noteworthy, incubation of leaf discs with levan and co-incubation with high levan-producing bacteria selectively up-regulated transcript levels of Zm-6-FEH, accompanied by an increase of 6-FEH enzyme activity. In summary, the results indicate that Zm-6-FEH, a novel fructan exohydrolase of a non-fructan species, may have a role in plant defense against levan-producing bacteria.
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Affiliation(s)
- Xiaojia Huang
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Wei Luo
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Silin Wu
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Yuming Long
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Rui Li
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Fenghua Zheng
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Steffen Greiner
- Centre for Organismal Studies Heidelberg, Department of Plant Molecular Physiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Thomas Rausch
- Centre for Organismal Studies Heidelberg, Department of Plant Molecular Physiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Hongbo Zhao
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
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44
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Jakob F, Gebrande C, Bichler RM, Vogel RF. Insights into the pH-dependent, extracellular sucrose utilization and concomitant levan formation by Gluconobacter albidus TMW 2.1191. Antonie Van Leeuwenhoek 2020; 113:863-873. [PMID: 32130597 PMCID: PMC7272483 DOI: 10.1007/s10482-020-01397-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 02/20/2020] [Indexed: 01/21/2023]
Abstract
Many bacteria and archaea produce the polydisperse fructose polymer levan from sucrose upon biofilm formation via extracellular levansucrases (EC 2.4.1.10). We have investigated levansucrase-release and -activities as well as molecular size of the levan formed by the acetic acid bacterium Gluconobacter albidus TMW 2.1191 at varying environmental pH conditions to obtain insight in the ecological role of its constitutively expressed levansucrase and the produced levan. A buffer system was established enabling the recovery of levansucrase-containing supernatants from preincubated cell suspensions at pH 4.3-pH 5.7. The enzyme solutions were used to produce levans at different pH values and sucrose concentrations. Finally, the amounts and size distributions of the produced levans as well as the corresponding levansucrase activities were determined and correlated with each other. The data revealed that the levansucrase was released into the environment independently of its substrate sucrose, and that more levansucrase was released at pH ≥ 5.0. The glucose release and formation of high molecular weight levans (> 3.5 kDa) from 0.1 M initial sucrose was comparable between pH ~ 4.3-5.7 using equal amounts of released levansucrase. Hence, this type of levansucrase appears to be structurally adapted to changes in the extracellular pH and to exhibit a similar total activity over a wide acidic pH range, while it produced higher amounts of larger levan molecules at higher production pH and sucrose concentrations. These findings indicate the physiological adaptation of G. albidus TMW 2.1191 to efficient colonisation of sucrose-rich habitats via released levansucrases despite changing extracellular pH conditions in course of acid formation.
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Affiliation(s)
- Frank Jakob
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Gregor-Mendel-Straße 4, 85354, Freising, Germany.
| | - Clara Gebrande
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Regina M Bichler
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Rudi F Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Gregor-Mendel-Straße 4, 85354, Freising, Germany
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45
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Yang HW, Yu M, Lee JH, Chatnaparat T, Zhao Y. The stringent response regulator (p) ppGpp mediates virulence gene expression and survival in Erwinia amylovora. BMC Genomics 2020; 21:261. [PMID: 32228459 PMCID: PMC7106674 DOI: 10.1186/s12864-020-6699-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/24/2020] [Indexed: 01/30/2023] Open
Abstract
Background The nucleotide second messengers, i.e., guanosine tetraphosphate and pentaphosphate [collectively referred to as (p) ppGpp], trigger the stringent response under nutrient starvation conditions and play an essential role in virulence in the fire blight pathogen Erwinia amylovora. Here, we present transcriptomic analyses to uncover the overall effect of (p) ppGpp-mediated stringent response in E. amylovora in the hrp-inducing minimal medium (HMM). Results In this study, we investigated the transcriptomic changes of the (p) ppGpp0 mutant under the type III secretion system (T3SS)-inducing condition using RNA-seq. A total of 1314 differentially expressed genes (DEGs) was uncovered, representing more than one third (36.8%) of all genes in the E. amylovora genome. Compared to the wild-type, the (p) ppGpp0 mutant showed down-regulation of genes involved in peptide ATP-binding cassette (ABC) transporters and virulence-related processes, including type III secretion system (T3SS), biofilm, and motility. Interestingly, in contrast to previous reports, the (p) ppGpp0 mutant showed up-regulation of amino acid biosynthesis genes, suggesting that it might be due to that these amino acid biosynthesis genes are indirectly regulated by (p) ppGpp in E. amylovora or represent specific culturing condition used. Furthermore, the (p) ppGpp0 mutant exhibited up-regulation of genes involved in translation, SOS response, DNA replication, chromosome segregation, as well as biosynthesis of nucleotide, fatty acid and lipid. Conclusion These findings suggested that in HMM environment, E. amylovora might use (p) ppGpp as a signal to activate virulence gene expression, and simultaneously mediate the balance between virulence and survival by negatively regulating DNA replication, translation, cell division, as well as biosynthesis of nucleotide, amino acid, fatty acid, and lipid. Therefore, (p) ppGpp could be a promising target for developing novel control measures to fight against this devastating disease of apples and pears.
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Affiliation(s)
- Ho-Wen Yang
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr, Urbana, IL, 61801, USA
| | - Menghao Yu
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr, Urbana, IL, 61801, USA
| | - Jae Hoon Lee
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr, Urbana, IL, 61801, USA
| | - Tiyakhon Chatnaparat
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr, Urbana, IL, 61801, USA
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr, Urbana, IL, 61801, USA.
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46
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Nascimento FX, Hernandez AG, Glick BR, Rossi MJ. The extreme plant-growth-promoting properties of Pantoea phytobeneficialis MSR2 revealed by functional and genomic analysis. Environ Microbiol 2020; 22:1341-1355. [PMID: 32077227 DOI: 10.1111/1462-2920.14946] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 02/13/2020] [Indexed: 12/18/2022]
Abstract
Numerous Pantoea strains are important because of the benefit they provide in the facilitation of plant growth. However, Pantoea have a high level of genotypic diversity and not much is understood regarding their ability to function in a plant beneficial manner. In the work reported here, the plant growth promotion activities and the genomic properties of the unusual Pantoea phytobeneficialis MSR2 are elaborated, emphasizing the genetic mechanisms involved in plant colonization and growth promotion. Detailed analysis revealed that strain MSR2 belongs to a rare group of Pantoea strains possessing an astonishing number of plant growth promotion genes, including those involved in nitrogen fixation, phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid deaminase activity, indoleacetic acid and cytokinin biosynthesis, and jasmonic acid metabolism. Moreover, the genome of this bacterium also contains genes involved in the metabolism of lignin and other plant cell wall compounds, quorum-sensing mechanisms, metabolism of plant root exudates, bacterial attachment to plant surfaces and resistance to plant defences. Importantly, the analysis revealed that most of these genes are present on accessory plasmids that are found within a small subset of Pantoea genomes, reinforcing the idea that Pantoea evolution is largely mediated by plasmids, providing new insights into the evolution of beneficial plant-associated Pantoea.
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Affiliation(s)
- Francisco X Nascimento
- IBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal.,Departamento de Microbiologia, Laboratório de Microbiologia e Bioprocessos, Universidade Federal de Santa Catarina, Florianópolis, 88040-900, SC, Brazil
| | - Anabel G Hernandez
- Departamento de Microbiologia, Laboratório de Microbiologia e Bioprocessos, Universidade Federal de Santa Catarina, Florianópolis, 88040-900, SC, Brazil
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, ON, Canada
| | - Márcio J Rossi
- Departamento de Microbiologia, Laboratório de Microbiologia e Bioprocessos, Universidade Federal de Santa Catarina, Florianópolis, 88040-900, SC, Brazil
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47
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Hundschell CS, Braun A, Wefers D, Vogel RF, Jakob F. Size-Dependent Variability in Flow and Viscoelastic Behavior of Levan Produced by Gluconobacter albidus TMW 2.1191. Foods 2020; 9:E192. [PMID: 32075024 PMCID: PMC7073539 DOI: 10.3390/foods9020192] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/05/2020] [Accepted: 02/11/2020] [Indexed: 12/15/2022] Open
Abstract
Levan is a fructan-type exopolysaccharide which is produced by many microbes from sucrose via extracellular levansucrases. The hydrocolloid properties of levan depend on its molecular weight, while it is unknown why and to what extent levan is functionally diverse depending on its size. The aim of our study was to gain deeper insight into the size-dependent functional variability of levan. For this purpose, levans of different sizes were produced using the water kefir isolate Gluconobacter albidus TMW 2.1191 and subsequently rheologically characterized. Three levan types could be identified, which are similarly branched, but differ significantly in their molecular size and rheological properties. The smallest levan (<107 Da), produced without adjustment of the pH, exhibited Newton-like flow behavior up to a specific concentration of 25% (w/v). By contrast, larger levans (>108 Da) produced at pH ≥ 4.5 were shear-thinning, and the levan produced at pH 5.0 showed a gel-like behavior at 5% (w/v). A third (intermediate) levan variant was obtained through production in buffers at pH 4.0 and exhibited the properties of a viscoelastic fluid up to concentrations of 15% (w/v). Our study reveals that the rheological properties of levan are determined by its size and polydispersity, rather than by the amount of levan used or the structural composition.
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Affiliation(s)
- Christoph S. Hundschell
- Chair of Technical Microbiology, Technical University of Munich, Gregor-Mendel-Straße 4, 85354 Freising, Germany;
- Department of Food Technology and Food Material Science, Technical University of Berlin, 14195 Berlin, Germany;
| | - Andre Braun
- Anton Paar Germany GmbH, Hellmuth-Hirth-Strasse 6, 73760 Ostfildern-Scharnhausen, Germany;
- Lehrstuhl für Systemverfahrenstechnik, Technische Universität München, Gregor-Mendel-Straße 4, 85354 Freising, Germany
| | - Daniel Wefers
- Division of Food Chemistry, Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany;
- Department of Food Chemistry and Phytochemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Rudi F. Vogel
- Chair of Technical Microbiology, Technical University of Munich, Gregor-Mendel-Straße 4, 85354 Freising, Germany;
| | - Frank Jakob
- Chair of Technical Microbiology, Technical University of Munich, Gregor-Mendel-Straße 4, 85354 Freising, Germany;
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Schachterle JK, Onsay DM, Sundin GW. Small RNA ArcZ Regulates Oxidative Stress Response Genes and Regulons in Erwinia amylovora. Front Microbiol 2019; 10:2775. [PMID: 31849909 PMCID: PMC6895013 DOI: 10.3389/fmicb.2019.02775] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/14/2019] [Indexed: 12/14/2022] Open
Abstract
Erwinia amylovora, causative agent of fire blight disease of apple and pear trees, has evolved to use small RNAs for post-transcriptional regulation of virulence traits important for disease development. The sRNA ArcZ regulates several virulence traits, and to better understand its roles, we conducted a transcriptomic comparison of wild-type and ΔarcZ mutant E. amylovora. We found that ArcZ regulates multiple cellular processes including genes encoding enzymes involved in mitigating the threat of reactive oxygen species (katA, tpx, osmC), and that the ΔarcZ mutant has reduced catalase activity and is more susceptible to exogenous hydrogen peroxide. We quantified hydrogen peroxide production by apple leaves inoculated with E. amylovora and found that the while wild-type E. amylovora cells produce enough catalase to cope with defense peroxide, the ΔarcZ mutant is likely limited in virulence because of inability to cope with peroxide levels in host leaves. We further found that the ArcZ regulon overlaps significantly with the regulons of transcription factors involved in oxidative sensing including Fnr and ArcA. In addition, we show that ArcZ regulates arcA at the post-transcriptional level suggesting a role for this system in mediating adaptations to oxidative state, especially during disease development.
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Affiliation(s)
- Jeffrey K Schachterle
- Genetics Graduate Program, Michigan State University, East Lansing, MI, United States.,Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - Daphne M Onsay
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - George W Sundin
- Genetics Graduate Program, Michigan State University, East Lansing, MI, United States.,Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States
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Kurilla A, Toth T, Dorgai L, Darula Z, Lakatos T, Silhavy D, Kerenyi Z, Dallmann G. Nectar- and stigma exudate-specific expression of an acidic chitinase could partially protect certain apple cultivars against fire blight disease. PLANTA 2019; 251:20. [PMID: 31781986 DOI: 10.1007/s00425-019-03303-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
MAIN CONCLUSION Certain apple cultivars accumulate to high levels in their nectar and stigma exudate an acidic chitinase III protein that can protect against pathogens including fire blight disease causing Erwinia amylovora. To prevent microbial infections, flower nectars and stigma exudates contain various antimicrobial compounds. Erwinia amylovora, the causing bacterium of the devastating fire blight apple disease, is the model pathogen that multiplies in flower secretions and infects through the nectaries. Although Erwinia-resistant apples are not available, certain cultivars are tolerant. It was reported that in flower infection assay, the 'Freedom' cultivar was Erwinia tolerant, while the 'Jonagold' cultivar was susceptible. We hypothesized that differences in the nectar protein compositions lead to different susceptibility. Indeed, we found that an acidic chitinase III protein (Machi3-1) selectively accumulates to very high levels in the nectar and the stigma exudate of the 'Freedom' cultivar. We show that three different Machi3-1 alleles exist in apple cultivars and that only the 5B-Machi3-1 allele expresses the Machi3-1 protein in the nectar and the stigma exudate. We demonstrate that the 5B-Machi3-1 allele was introgressed from the Malus floribunda 821 clone into different apple cultivars including the 'Freedom'. Our data suggest that MYB-binding site containing repeats of the 5B-Machi3-1 promoter is responsible for the strong nectar- and stigma exudate-specific expression. As we found that in vitro, the Machi3-1 protein impairs growth and biofilm formation of Erwinia at physiological concentration, we propose that the Machi3-1 protein could partially protect 5B-Machi3-1 allele containing cultivars against Erwinia by inhibiting the multiplication and biofilm formation of the pathogen in the stigma exudate and in the nectar.
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Affiliation(s)
- Anita Kurilla
- Agricultural Biotechnology Institute, Szent-Györgyi 4, Gödöllő, 2100, Hungary
| | - Timea Toth
- Research Institute for Fruitgrowing and Ornamentals, Park 2, Budapest, 1223, Hungary
| | | | - Zsuzsanna Darula
- Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt 62, Szeged, 6726, Hungary
| | - Tamas Lakatos
- Research Institute for Fruitgrowing and Ornamentals, Park 2, Budapest, 1223, Hungary
| | - Daniel Silhavy
- Agricultural Biotechnology Institute, Szent-Györgyi 4, Gödöllő, 2100, Hungary.
- Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt 62, Szeged, 6726, Hungary.
| | - Zoltan Kerenyi
- Agricultural Biotechnology Institute, Szent-Györgyi 4, Gödöllő, 2100, Hungary
- MTKI, Lucsony 24, Mosonmagyaróvár, 9200, Hungary
| | - Geza Dallmann
- Agricultural Biotechnology Institute, Szent-Györgyi 4, Gödöllő, 2100, Hungary
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Host Range of Bacteriophages Against a World-Wide Collection of Erwinia amylovora Determined Using a Quantitative PCR Assay. Viruses 2019; 11:v11100910. [PMID: 31581574 PMCID: PMC6832558 DOI: 10.3390/v11100910] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/21/2019] [Accepted: 09/27/2019] [Indexed: 01/01/2023] Open
Abstract
Erwinia amylovora is a globally devastating pathogen of apple, pear, and other Rosaceous plants. The use of lytic bacteriophages for disease management continues to garner attention as a possible supplement or alternative to antibiotics. A quantitative productive host range was established for 10 Erwinia phages using 106 wild type global isolates of E. amylovora, and the closely related Erwinia pyrifoliae, to investigate the potential regional efficacy of these phages within a biopesticide. Each host was individually infected with each of the 10 Erwinia phages and phage production after 8 h incubation was measured using quantitative real time PCR (qPCR) in conjunction with a standardized plasmid. PCR amplicons for all phages used in the study were incorporated into a single plasmid, allowing standardized quantification of the phage genome copy number after the infection process. Nine of the tested phages exhibited a broad host range, replicating their genomes by at least one log in over 88% of tested hosts. Also, every Amygdaloideae infecting E. amylovora host was able to increase at least one phage by three logs. Bacterial hosts isolated in western North America were less susceptible to most phages, as the mean genomic titre produced dropped by nearly two logs, and this phenomenon was strongly correlated to the amount of exopolysaccharide produced by the host. This method of host range analysis is faster and requires less effort than traditional plaque assay techniques, and the resulting quantitative data highlight subtle differences in phage host preference not observable with typical plaque-based host range assays. These quantitative host range data will be useful to determine which phages should be incorporated into a phage-mediated biocontrol formulation to be tested for regional and universal control of E. amylovora.
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