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Arahal DR, Bull CT, Christensen H, Chuvochina M, Dunlap C, del Carmen Montero-Calasanz M, Parker CT, Vandamme P, Ventosa A, Ventura S, Young P, Göker M. Judicial Opinion 130. Int J Syst Evol Microbiol 2024; 74:006414. [PMID: 38841989 PMCID: PMC11261725 DOI: 10.1099/ijsem.0.006414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 05/26/2024] [Indexed: 06/07/2024] Open
Abstract
Opinion 130 deals with a Request for an Opinion asking the Judicial Commission to clarify whether the genus name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate. The Request is approved and an answer is given. The name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate because it is a later homonym of the validly published cyanobacterial name Rhodococcus Hansgirg 1884. The Judicial Commission also clarifies that it has the means to resolve such cases by conserving a name over an earlier homonym. It is concluded that the name Rhodococcus Zopf 1891 (Approved Lists 1980) is significantly more important than the name Rhodococcus Hansgirg 1884 and therefore the former is conserved over the latter. This makes the name Rhodococcus Zopf 1891 (Approved Lists 1980) legitimate.
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Affiliation(s)
- David R. Arahal
- Departamento de Microbiología y Ecología, Universitat de València, Valencia, Spain
| | - Carolee T. Bull
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, 211 Buckhout Lab, University Park, PA 16802, USA
| | - Henrik Christensen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
| | - Maria Chuvochina
- The University of Queensland, School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, QLD 4072, Australia
| | - Christopher Dunlap
- Crop Bioprotection Research Unit, USDA/ARS/NCAUR, 1815 N. University St, 61604 Peoria, Illinois, USA
| | - Maria del Carmen Montero-Calasanz
- IFAPA Las Torres - Andalusian Institute of Agricultural and Fisheries Research and Training, Cra. Sevilla-Cazalla de la Sierra, 41200, Alcalá del Río, Sevilla, Spain
| | - Charles T. Parker
- Department of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Peter Vandamme
- BCCM/LMG, Laboratorium voor Microbiologie, Universiteit Gent (UGent) K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, C/. Prof. Garcia Gonzalez 2, ES-41012 Sevilla, Spain
| | - Stefano Ventura
- IRET-CNR, Research Institute on Terrestrial Ecosystems, National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, and NBCF, National Biodiversity Future Center, Palermo, Italy
| | - Peter Young
- Department of Biology, University of York, York YO10 5DD, UK
| | - Markus Göker
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstrasse 7B, D-38124 Braunschweig, Germany
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2
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Gätjens-Boniche O, Jiménez-Madrigal JP, Whetten RW, Valenzuela-Diaz S, Alemán-Gutiérrez A, Hanson PE, Pinto-Tomás AA. Microbiome and plant cell transformation trigger insect gall induction in cassava. FRONTIERS IN PLANT SCIENCE 2023; 14:1237966. [PMID: 38126017 PMCID: PMC10731979 DOI: 10.3389/fpls.2023.1237966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
Several specialised insects can manipulate normal plant development to induce a highly organised structure known as a gall, which represents one of the most complex interactions between insects and plants. Thus far, the mechanism for insect-induced plant galls has remained elusive. To study the induction mechanism of insect galls, we selected the gall induced by Iatrophobia brasiliensis (Diptera: Cecidomyiidae) in cassava (Euphorbiaceae: Manihot esculenta Crantz) as our model. PCR-based molecular markers and deep metagenomic sequencing data were employed to analyse the gall microbiome and to test the hypothesis that gall cells are genetically transformed by insect vectored bacteria. A shotgun sequencing discrimination approach was implemented to selectively discriminate between foreign DNA and the reference host plant genome. Several known candidate insertion sequences were identified, the most significant being DNA sequences found in bacterial genes related to the transcription regulatory factor CadR, cadmium-transporting ATPase encoded by the cadA gene, nitrate transport permease protein (nrtB gene), and arsenical pump ATPase (arsA gene). In addition, a DNA fragment associated with ubiquitin-like gene E2 was identified as a potential accessory genetic element involved in gall induction mechanism. Furthermore, our results suggest that the increased quality and rapid development of gall tissue are mostly driven by microbiome enrichment and the acquisition of critical endophytes. An initial gall-like structure was experimentally obtained in M. esculenta cultured tissues through inoculation assays using a Rhodococcus bacterial strain that originated from the inducing insect, which we related to the gall induction process. We provide evidence that the modification of the endophytic microbiome and the genetic transformation of plant cells in M. esculenta are two essential requirements for insect-induced gall formation. Based on these findings and having observed the same potential DNA marker in galls from other plant species (ubiquitin-like gene E2), we speculate that bacterially mediated genetic transformation of plant cells may represent a more widespread gall induction mechanism found in nature.
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Affiliation(s)
- Omar Gätjens-Boniche
- Laboratorio de Biología Molecular, Escuela de Ciencias Naturales y Exactas, Campus Tecnológico Local San Carlos, Instituto Tecnológico de Costa Rica, Alajuela, Costa Rica
| | - Jose Pablo Jiménez-Madrigal
- Laboratorio de Biología Molecular, Escuela de Ciencias Naturales y Exactas, Campus Tecnológico Local San Carlos, Instituto Tecnológico de Costa Rica, Alajuela, Costa Rica
| | - Ross W. Whetten
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, United States
| | - Sandro Valenzuela-Diaz
- Human Microbiome Research Program, Faculty of Medicine, The Helsinki University, Helsinki, Finland
| | - Alvaro Alemán-Gutiérrez
- Laboratorio de Biología Molecular, Escuela de Ciencias Naturales y Exactas, Campus Tecnológico Local San Carlos, Instituto Tecnológico de Costa Rica, Alajuela, Costa Rica
- Laboratorio de Genómica y Biodiversidad, Facultad de Ciencias, Universidad del Bío-Bío, Chillán, Chile
| | - Paul E. Hanson
- Escuela de Biología, Universidad de Costa Rica, San Pedro, San José, Costa Rica
| | - Adrián A. Pinto-Tomás
- Center for Research in Microscopic Structures and Department of Biochemistry, School of Medicine, University of Costa Rica, San José, Costa Rica
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Nazarov PA, Majorov KB, Apt AS, Skulachev MV. Penetration of Triphenylphosphonium Derivatives through the Cell Envelope of Bacteria of Mycobacteriales Order. Pharmaceuticals (Basel) 2023; 16:ph16050688. [PMID: 37242470 DOI: 10.3390/ph16050688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/20/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
The penetration of substances through the bacterial cell envelope is a complex and underinvestigated process. Mitochondria-targeted antioxidant and antibiotic SkQ1 (10-(plastoquinonyl)decyltriphenylphosphonium) is an excellent model for studying the penetration of substances through the bacterial cell envelope. SkQ1 resistance in Gram-negative bacteria has been found to be dependent on the presence of the AcrAB-TolC pump, while Gram-positive bacteria do not have this pump but, instead, have a mycolic acid-containing cell wall that is a tough barrier against many antibiotics. Here, we report the bactericidal action of SkQ1 and dodecyl triphenylphospho-nium (C12TPP) against Rhodococcus fascians and Mycobacterium tuberculosis, pathogens of plants and humans. The mechanism of the bactericidal action is based on the penetration of SkQ1 and C12TPP through the cell envelope and the disruption of the bioenergetics of bacteria. One, but probably not the only such mechanism is a decrease in membrane potential, which is important for the implementation of many cellular processes. Thus, neither the presence of MDR pumps, nor the presence of porins, prevents the penetration of SkQ1 and C12TPP through the complex cell envelope of R. fascians and M. tuberculosis.
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Affiliation(s)
- Pavel A Nazarov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Alexander S Apt
- Central Research Institute for Tuberculosis, 107564 Moscow, Russia
| | - Maxim V Skulachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Mitotech LLC, 119991 Moscow, Russia
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Putrescine: A Key Metabolite Involved in Plant Development, Tolerance and Resistance Responses to Stress. Int J Mol Sci 2022; 23:ijms23062971. [PMID: 35328394 PMCID: PMC8955586 DOI: 10.3390/ijms23062971] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 02/06/2023] Open
Abstract
Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research.
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Pátek M, Grulich M, Nešvera J. Stress response in Rhodococcus strains. Biotechnol Adv 2021; 53:107698. [PMID: 33515672 DOI: 10.1016/j.biotechadv.2021.107698] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 12/13/2022]
Abstract
Rhodococci are bacteria which can survive under various extreme conditions, in the presence of toxic compounds, and in other hostile habitats. Their tolerance of unfavorable conditions is associated with the structure of their cell wall and their large array of enzymes, which degrade or detoxify harmful compounds. Their physiological and biotechnological properties, together with tools for their genetic manipulation, enable us to apply them in biotransformations, biodegradation and bioremediation. Many such biotechnological applications cause stresses that positively or negatively affect their efficiency. Whereas numerous reviews on rhodococci described their enzyme activities, the optimization of degradation or production processes, and corresponding technological solutions, only a few reviews discussed some specific effects of stresses on the physiology of rhodococci and biotechnological processes. This review aims to comprehensively describe individual stress responses in Rhodococcus strains, the interconnection of different types of stresses and their consequences for cell physiology. We examine here the responses to (1) environmental stresses (desiccation, heat, cold, osmotic and pH stress), (2) the presence of stress-inducing compounds (metals, organic compounds and antibiotics) in the environment (3) starvation and (4) stresses encountered during biotechnological applications. Adaptations of the cell envelope, the formation of multicellular structures and stresses induced by the interactions of hosts with pathogenic rhodococci are also included. The roles of sigma factors of RNA polymerase in the global regulation of stress responses in rhodococci are described as well. Although the review covers a large number of stressful conditions, our intention was to provide an overview of the selected stress responses and their possible connection to biotechnological processes, not an exhaustive survey of the scientific literature. The findings on stress responses summarized in this review and the demonstration of gaps in current knowledge may motivate researchers working to fill these gaps.
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Affiliation(s)
- Miroslav Pátek
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic.
| | - Michal Grulich
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic.
| | - Jan Nešvera
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic.
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Dolzblasz A, Banasiak A, Vereecke D. A sustained CYCLINB1;1 and STM expression in the neoplastic tissues induced by Rhodococcus fascians on Arabidopsis underlies the persistence of the leafy gall structure. PLANT SIGNALING & BEHAVIOR 2020; 15:1816320. [PMID: 32897774 PMCID: PMC7676816 DOI: 10.1080/15592324.2020.1816320] [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: 06/29/2020] [Revised: 08/21/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
is a gram-positive phytopathogen that infects a wide range of plant species. The actinomycete induces the formation of neoplastic growths, termed leafy galls, that consist of a gall body covered by small shoots of which the outgrowth is arrested due to an extreme form of apical dominance. In our previous work, we demonstrated that in the developing gall, auxin drives the transdifferentiation of parenchyma cells into vascular elements. In this work, with the use of transgenic Arabidopsis thaliana plants carrying molecular reporters for cell division (pCYCB1;1:GUS) and meristematic activity (pSTM:GUS), we analyzed the fate of cells within the leafy gall. Our results indicate that the size of the gall body is determined by ongoing mitotic cell divisions as illustrated by strong CYCB1;1 expression combined with the de novo formation of new meristematic areas triggered by STM expression. The shoot meristems that develop in the peripheral parts of the gall are originating from high ectopic STM expression. Altogether the presented data provide further insight into the cellular events that accompany the development of leafy galls in response to R. fascians infection.
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Affiliation(s)
- Alicja Dolzblasz
- Department of Plant Developmental Biology, Faculty of Biological Sciences, Institute of Experimental Biology, University of Wroclaw, Wrocław, Poland
| | - Alicja Banasiak
- Department of Plant Developmental Biology, Faculty of Biological Sciences, Institute of Experimental Biology, University of Wroclaw, Wrocław, Poland
| | - Danny Vereecke
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Department of Entomology, Plant Pathology, and Weed Sciences, New Mexico State University, NM, USA
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Savory EA, Weisberg AJ, Stevens DM, Creason AL, Fuller SL, Pearce EM, Chang JH. Phytopathogenic Rhodococcus Have Diverse Plasmids With Few Conserved Virulence Functions. Front Microbiol 2020; 11:1022. [PMID: 32523572 PMCID: PMC7261884 DOI: 10.3389/fmicb.2020.01022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 04/27/2020] [Indexed: 11/13/2022] Open
Abstract
Rhodococcus is a genus of Gram-positive bacteria with species that can cause growth deformations to a large number of plant species. This ability to cause disease is hypothesized to be dependent on a cluster of three gene loci on an almost 200 kb-sized linear plasmid. To reevaluate the roles of some of the genes in pathogenicity, we constructed and characterized deletion mutants of fasR and four fas genes. Findings confirmed that fasR, which encodes a putative transcriptional regulator, is necessary for pathogenesis. However, three of the fas genes, implicated in the metabolism of plant growth promoting cytokinins, are dispensable for the ability of the pathogen to cause disease. We also used long-read sequencing technology to generate high quality genome sequences for two phytopathogenic strains in which virulence genes are diverged in sequence and/or hypothesized to have recombined into the chromosome. Surprisingly, findings showed that the two strains carry extremely diverse virulence plasmids. Ortholog clustering identified only 12 genes present on all three virulence plasmids. Rhodococcus requires a small number of horizontally acquired traits to be pathogenic and the transmission of the corresponding genes, via recombination and conjugation, has the potential to rapidly diversify plasmids and bacterial populations.
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Affiliation(s)
- Elizabeth A Savory
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Danielle M Stevens
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Allison L Creason
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Skylar L Fuller
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Emma M Pearce
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States.,Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
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8
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Vereecke D, Zhang Y, Francis IM, Lambert PQ, Venneman J, Stamler RA, Kilcrease J, Randall JJ. Functional Genomics Insights Into the Pathogenicity, Habitat Fitness, and Mechanisms Modifying Plant Development of Rhodococcus sp. PBTS1 and PBTS2. Front Microbiol 2020; 11:14. [PMID: 32082278 PMCID: PMC7002392 DOI: 10.3389/fmicb.2020.00014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/06/2020] [Indexed: 01/05/2023] Open
Abstract
Pistachio Bushy Top Syndrome (PBTS) is a recently emerged disease that has strongly impacted the pistachio industry in California, Arizona, and New Mexico. The disease is caused by two bacteria, designated PBTS1 that is related to Rhodococcus corynebacterioides and PBTS2 that belongs to the species R. fascians. Here, we assessed the pathogenic character of the causative agents and examined their chromosomal sequences to predict the presence of particular functions that might contribute to the observed co-occurrence and their effect on plant hosts. In diverse assays, we confirmed the pathogenicity of the strains on "UCB-1" pistachio rootstock and showed that they can also impact the development of tobacco species, but concurrently inconsistencies in the ability to induce symptoms were revealed. We additionally evidence that fas genes are present only in a subpopulation of pure PBTS1 and PBTS2 cultures after growth on synthetic media, that these genes are easily lost upon cultivation in rich media, and that they are enriched for in an in planta environment. Analysis of the chromosomal sequences indicated that PBTS1 and PBTS2 might have complementary activities that would support niche partitioning. Growth experiments showed that the nutrient utilization pattern of both PBTS bacteria was not identical, thus avoiding co-inhabitant competition. PBTS2 appeared to have the potential to positively affect the habitat fitness of PBTS1 by improving its resistance against increased concentrations of copper and penicillins. Finally, mining the chromosomes of PBTS1 and PBTS2 suggested that the bacteria could produce cytokinins, auxins, and plant growth-stimulating volatiles and that PBTS2 might interfere with ethylene levels, in support of their impact on plant development. Subsequent experimentation supported these in silico predictions. Altogether, our data provide an explanation for the observed pathogenic behavior and unveil part of the strategies used by PBTS1 and PBTS2 to interact with plants.
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Affiliation(s)
- Danny Vereecke
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
| | - Yucheng Zhang
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | - Isolde M Francis
- Department of Biology, California State University, Bakersfield, CA, United States
| | - Paul Q Lambert
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
| | - Jolien Venneman
- Department of Plants and Crops, Ghent University, Ghent, Belgium
| | - Rio A Stamler
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
| | - James Kilcrease
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
| | - Jennifer J Randall
- Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM, United States
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Thapa SP, Davis EW, Lyu Q, Weisberg AJ, Stevens DM, Clarke CR, Coaker G, Chang JH. The Evolution, Ecology, and Mechanisms of Infection by Gram-Positive, Plant-Associated Bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:341-365. [PMID: 31283433 DOI: 10.1146/annurev-phyto-082718-100124] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Gram-positive bacteria are prominent members of plant-associated microbial communities. Although many are hypothesized to be beneficial, some are causative agents of economically important diseases of crop plants. Because the features of Gram-positive bacteria are fundamentally different relative to those of Gram-negative bacteria, the evolution and ecology as well as the mechanisms used to colonize and infect plants also differ. Here, we discuss recent advances in our understanding of Gram-positive, plant-associated bacteria and provide a framework for future research directions on these important plant symbionts.
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Affiliation(s)
- Shree P Thapa
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Edward W Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA
| | - Qingyang Lyu
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
| | - Danielle M Stevens
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Integrative Genetics and Genomics, University of California, Davis, California 95616, USA
| | - Christopher R Clarke
- Genetic Improvement for Fruits and Vegetables Laboratory, Agricultural Research Service, US Department of Agriculture, Beltsville, Maryland 20705, USA
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA;
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA
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Jaworek P, Kopečný D, Zalabák D, Šebela M, Kouřil Š, Hluska T, Končitíková R, Podlešáková K, Tarkowski P. Occurrence and biosynthesis of cytokinins in poplar. PLANTA 2019; 250:229-244. [PMID: 30980246 DOI: 10.1007/s00425-019-03152-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Isoprenoid and aromatic cytokinins occur in poplar as free compounds and constituents of tRNA, poplar isopentenyltransferases are involved in the production of isoprenoid cytokinins, while biosynthesis of their aromatic counterparts remains unsolved. Cytokinins are phytohormones with a fundamental role in the regulation of plant growth and development. They occur naturally either as isoprenoid or aromatic derivatives, but the latter are quite rare and less studied. Here, the spatial expression of all nine isopentenyl transferase genes of Populus × canadensis cv. Robusta (PcIPTs) as analyzed by RT-qPCR revealed a tissue preference and strong differences in expression levels for the different adenylate and tRNA PcIPTs. Together with their phylogeny, this result suggests a functional diversification for the different PcIPT proteins. Additionally, the majority of PcIPT genes were cloned and expressed in Arabidopsis thaliana under an inducible promoter. The cytokinin levels measured in the Arabidopsis-overexpressing lines as well as their phenotype indicate that the studied adenylate and tRNA PcIPT proteins are functional in vivo and thus will contribute to the cytokinin pool in poplar. We screened the cytokinin content in leaves of 12 Populus species by ultra-high performance-tandem mass spectrometry (UHPLC-MS/MS) and discovered that the capacity to produce not only isoprenoid, but also aromatic cytokinins is widespread amongst the Populus accessions studied. Important for future studies is that the levels of aromatic cytokinins transiently increase after daybreak and are much higher in older plants.
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Affiliation(s)
- Pavel Jaworek
- Department of Phytochemistry, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - David Kopečný
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - David Zalabák
- Department of Molecular Biology, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Marek Šebela
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Štěpán Kouřil
- Department of Phytochemistry, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Tomáš Hluska
- Department of Genetic Resources for Vegetables, Medicinal and Special Plants, Centre of the Region Hana for Biotechnological and Agricultural Research, Crop Research Institute, Šlechtitelů 29, 78371, Olomouc, Czech Republic
| | - Radka Končitíková
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Kateřina Podlešáková
- Department of Biochemistry, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Petr Tarkowski
- Department of Phytochemistry, Faculty of Science, Centre of the Region Hana for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 78371, Olomouc, Czech Republic.
- Department of Genetic Resources for Vegetables, Medicinal and Special Plants, Centre of the Region Hana for Biotechnological and Agricultural Research, Crop Research Institute, Šlechtitelů 29, 78371, Olomouc, Czech Republic.
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11
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Body MJA, Zinkgraf MS, Whitham TG, Lin CH, Richardson RA, Appel HM, Schultz JC. Heritable Phytohormone Profiles of Poplar Genotypes Vary in Resistance to a Galling Aphid. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:654-672. [PMID: 30520677 DOI: 10.1094/mpmi-11-18-0301-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Insect galls are highly specialized structures arising from atypical development of plant tissue induced by insects. Galls provide the insect enhanced nutrition and protection against natural enemies and environmental stresses. Galls are essentially plant organs formed by an intimate biochemical interaction between the gall-inducing insect and its host plant. Because galls are plant organs, their development is likely to be governed by phytohormones involved in normal organogenesis. We characterized concentrations of both growth and defensive phytohormones in ungalled control leaves and galls induced by the aphid Pemphigus betae on narrowleaf cottonwood Populus angustifolia that differ genotypically in resistance to this insect. We found that susceptible trees differed from resistant trees in constitutive concentrations of both growth and defense phytohormones. Susceptible trees were characterized by significantly higher constitutive cytokinin concentrations in leaves, significantly greater ability of aphids to elicit cytokinin increases, and significantly lower constitutive defense phytohormone concentrations than observed in resistant trees. Phytohormone concentrations in both constitutive and induced responses in galled leaves exhibited high broad-sense heritability that, respectively, ranged from 0.39 to 0.93 and from 0.28 to 0.66, suggesting that selection can act upon these traits and that they might vary across the landscape. Increased cytokinin concentrations may facilitate forming strong photosynthate sinks in the galls, a requirement for galling insect success. By characterizing for the first time the changes in 15 phytohormones belonging to five different classes, this study offers a better overview of the signaling alteration occurring in galls that has likely been important for their ecology and evolution. Copyright © 2019 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)
- Mélanie J A Body
- 1 Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, U.S.A
| | - Matthew S Zinkgraf
- 2 Department of Biological Sciences and Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ 86011, U.S.A.; and
| | - Thomas G Whitham
- 2 Department of Biological Sciences and Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ 86011, U.S.A.; and
| | - Chung-Ho Lin
- 3 School of Natural Resources, 203 Anheuser-Busch Natural Resources Building, 1111 Rollins Street, University of Missouri, Columbia, MO 65201, U.S.A
| | - Ryan A Richardson
- 1 Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, U.S.A
| | - Heidi M Appel
- 1 Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, U.S.A
| | - Jack C Schultz
- 1 Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, U.S.A
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12
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Francis IM, Vereecke D. Plant-Associated Rhodococcus Species, for Better and for Worse. BIOLOGY OF RHODOCOCCUS 2019. [DOI: 10.1007/978-3-030-11461-9_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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13
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Jameson PE, Dhandapani P, Song J, Zatloukal M, Strnad M, Remus-Emsermann MNP, Schlechter RO, Novák O. The Cytokinin Complex Associated With Rhodococcus fascians: Which Compounds Are Critical for Virulence? FRONTIERS IN PLANT SCIENCE 2019; 10:674. [PMID: 31191583 PMCID: PMC6539147 DOI: 10.3389/fpls.2019.00674] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/03/2019] [Indexed: 05/22/2023]
Abstract
Virulent strains of Rhodococcus fascians cause a range of disease symptoms, many of which can be mimicked by application of cytokinin. Both virulent and avirulent strains produce a complex of cytokinins, most of which can be derived from tRNA degradation. To test the three current hypotheses regarding the involvement of cytokinins as virulence determinants, we used PCR to detect specific genes, previously associated with a linear virulence plasmid, including two methyl transferase genes (mt1 and mt2) and fas4 (dimethyl transferase), of multiple strains of R. fascians. We inoculated Pisum sativum (pea) seeds with virulent and avirulent strains of R. fascians, monitored the plants over time and compared these to mock-inoculated controls. We used RT-qPCR to monitor the expression of mt1, mt2, and fas4 in inoculated tissues and LC-MS/MS to obtain a comprehensive picture of the cytokinin complement of inoculated cotyledons, roots and shoots over time. The presence and expression of mt1 and mt2 was associated with those strains of R. fascians classed as virulent, and not those classed as avirulent. Expression of mt1, mt2, and fas4 peaked at 9 days post-inoculation (dpi) in cotyledons and at 15 dpi in shoots and roots developed from seeds inoculated with virulent strain 602. Pea plants inoculated with virulent and avirulent strains of R. fascians both contained cytokinins likely to have been derived from tRNA turnover including the 2-methylthio cytokinins and cis-zeatin-derivatives. Along with the isopentenyladenine-type cytokinins, the levels of these compounds did not correlate with virulence. Only the novel 1- and 2-methylated isopentenyladenine cytokinins were uniquely associated with infection by the virulent strains and are, therefore, the likely causative factors of the disease symptoms.
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Affiliation(s)
- Paula E. Jameson
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- *Correspondence: Paula E. Jameson
| | - Pragathi Dhandapani
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jiancheng Song
- School of Life Sciences, Yantai University, Yantai, China
| | - Marek Zatloukal
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
| | - Miroslav Strnad
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
| | | | - Rudolf O. Schlechter
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Ondrej Novák
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Faculty of Science, Institute of Experimental Botany & Palacký University, Olomouc, Czech Republic, China
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14
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Vereecke D. Comment on "Evolutionary transitions between beneficial and phytopathogenic Rhodococcus challenge disease management". eLife 2018; 7:35238. [PMID: 29737966 PMCID: PMC5951678 DOI: 10.7554/elife.35238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/13/2018] [Indexed: 02/06/2023] Open
Abstract
I would like to report significant issues of concern regarding this paper (Savory et al., 2017).
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Affiliation(s)
- Danny Vereecke
- Department of Applied Biosciences, Ghent University, Ghent, Belgium
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15
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Dolzblasz A, Banasiak A, Vereecke D. Neovascularization during leafy gall formation on Arabidopsis thaliana upon Rhodococcus fascians infection. PLANTA 2018; 247:215-228. [PMID: 28942496 DOI: 10.1007/s00425-017-2778-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Extensive de novo vascularization of leafy galls emerging upon Rhodococcus fascians infection is achieved by fascicular/interfascicular cambium activity and transdifferentiation of parenchyma cells correlated with increased auxin signaling. A leafy gall consisting of fully developed yet growth-inhibited shoots, induced by the actinomycete Rhodococcus fascians, differs in structure compared to the callus-like galls induced by other bacteria. To get insight into the vascular development accompanying the emergence of the leafy gall, the anatomy of infected axillary regions of the inflorescence stem of wild-type Arabidopsis thaliana accession Col-0 plants and the auxin response in pDR5:GUS-tagged plants were followed in time. Based on our observations, three phases can be discerned during vascularization of the symptomatic tissue. First, existing fascicular cambium becomes activated and interfascicular cambium is formed giving rise to secondary vascular elements in a basipetal direction below the infection site in the main stem and in an acropetal direction in the entire side branch. Then, parenchyma cells in the region between both stems transdifferentiate acropetally towards the surface of the developing symptomatic tissue leading to the formation of xylem and vascularize the hyperplasia as they expand. Finally, parenchyma cells in the developing gall also transdifferentiate to vascular elements without any specific direction resulting in excessive vasculature disorderly distributed in the leafy gall. Prior to any apparent anatomical changes, a strong auxin response is mounted, implying that auxin is the signal that controls the vascular differentiation induced by the infection. To conclude, we propose the "sidetracking gall hypothesis" as we discuss the mechanisms driving the formation of superfluous vasculature of the emerging leafy gall.
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Affiliation(s)
- Alicja Dolzblasz
- Department of Plant Developmental Biology, Faculty of Biological Sciences, Institute of Experimental Biology, University of Wroclaw, Wroclaw, Poland.
| | - Alicja Banasiak
- Department of Plant Developmental Biology, Faculty of Biological Sciences, Institute of Experimental Biology, University of Wroclaw, Wroclaw, Poland
| | - Danny Vereecke
- Department of Applied Biosciences, Ghent University, Ghent, Belgium.
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16
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Abstract
The acquisition of a virulence plasmid is sufficient to turn a beneficial strain of Rhodococcus bacteria into a pathogen.
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Affiliation(s)
- Ryan A Melnyk
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouverCanada
| | - Cara H Haney
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouverCanada
- Michael Smith LaboratoriesUniversity of British ColumbiaVancouverCanada
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17
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Savory EA, Fuller SL, Weisberg AJ, Thomas WJ, Gordon MI, Stevens DM, Creason AL, Belcher MS, Serdani M, Wiseman MS, Grünwald NJ, Putnam ML, Chang JH. Evolutionary transitions between beneficial and phytopathogenic Rhodococcus challenge disease management. eLife 2017; 6:30925. [PMID: 29231813 PMCID: PMC5726852 DOI: 10.7554/elife.30925] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/03/2017] [Indexed: 02/02/2023] Open
Abstract
Understanding how bacteria affect plant health is crucial for developing sustainable crop production systems. We coupled ecological sampling and genome sequencing to characterize the population genetic history of Rhodococcus and the distribution patterns of virulence plasmids in isolates from nurseries. Analysis of chromosome sequences shows that plants host multiple lineages of Rhodococcus, and suggested that these bacteria are transmitted due to independent introductions, reservoir populations, and point source outbreaks. We demonstrate that isolates lacking virulence genes promote beneficial plant growth, and that the acquisition of a virulence plasmid is sufficient to transition beneficial symbionts to phytopathogens. This evolutionary transition, along with the distribution patterns of plasmids, reveals the impact of horizontal gene transfer in rapidly generating new pathogenic lineages and provides an alternative explanation for pathogen transmission patterns. Results also uncovered a misdiagnosed epidemic that implicated beneficial Rhodococcus bacteria as pathogens of pistachio. The misdiagnosis perpetuated the unnecessary removal of trees and exacerbated economic losses. All organisms live in a world teeming with bacteria. Some bacteria are beneficial and, for example, provide their hosts with nutrients. Others cause harm, for example, by stealing nutrients and causing disease. Many bacteria can also gain DNA from other bacteria, and the genes encoded within the new DNA can help them to live with other organisms. This can start the bacteria on an evolutionary path to becoming beneficial or harmful. Rhodococcus are bacteria that live in association with many species of plants, including trees. Most are harmless but some cause disease. Plants infected with harmful Rhodococcus can show deformed growth, which causes major losses to the nursery industry. Savory, Fuller, Weisberg et al. set out to understand how disease-causing Rhodococcus are introduced into nurseries, if they are transferred between nurseries, whether they persist in nurseries, and how to limit their spread. It turns out that harmless Rhodococcus are beneficial to plants. However, if these harmless bacteria gain a certain DNA molecule – called a virulence plasmid – they can convert into harmful bacteria. Further analysis showed that some nurseries repeatedly acquired the harmful bacteria. The pattern of affected nurseries suggested that some might have purchased diseased plants from a common provider. In other cases, the sources remained a mystery. Savory et al. also report that, contrary to previous findings, there is no evidence to support the diagnosis that Rhodococcus without a virulence plasmid are responsible for an unusual growth problem that has plagued the pistachio industry. In recent years, this incorrect diagnosis led to trees being unnecessarily destroyed, worsening the economic losses. These findings suggest that genes moving between bacteria can dramatically change how those bacteria interact with the organisms in which they live. It needs to be shown whether this is an exceptional process, unique to only certain groups of bacteria, or if it is more widespread in nature. These findings could inform future disease management strategies to better protect agricultural systems.
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Affiliation(s)
- Elizabeth A Savory
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Skylar L Fuller
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - William J Thomas
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Michael I Gordon
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Danielle M Stevens
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Allison L Creason
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States
| | - Michael S Belcher
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Maryna Serdani
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Michele S Wiseman
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Niklaus J Grünwald
- Horticultural Crops Research Laboratory, United States Department of Agriculture and Agricultural Research Service, Corvallis, United States
| | - Melodie L Putnam
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States.,Center for Genome Research, Oregon State University, Corvallis, United States
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18
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Zhang H, Guiguet A, Dubreuil G, Kisiala A, Andreas P, Emery RJN, Huguet E, Body M, Giron D. Dynamics and origin of cytokinins involved in plant manipulation by a leaf-mining insect. INSECT SCIENCE 2017; 24:1065-1078. [PMID: 28636152 DOI: 10.1111/1744-7917.12500] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/03/2017] [Accepted: 06/08/2017] [Indexed: 05/22/2023]
Abstract
Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for their own benefit. The leaf-mining moth Phyllonorycter blancardella modifies the cytokinin (CK) profile of mined leaf-tissues, and the insect symbiotic bacteria Wolbachia is involved in the plant manipulation to the benefit of the insect host. To gain a deeper understanding into the possible origin and dynamics of CKs, we conducted an extensive characterization of CKs in larvae and in infected apple leaves. Our results show the enhanced CK levels in mines, both on green and yellow leaves, allowing insects to control their nutritional supply under fluctuating environmental conditions. The spatial distribution of CKs within the mined leaves shows that hormone manipulation is strictly limited to the mine suggesting the absence of CK translocation from distant leaf areas toward the insect feeding site. Mass spectrometry analyses reveal that major CK types accumulating in mines and larvae are similar to what is observed for most gall-inducers, suggesting that strategies underlying the plant manipulation may be shared between herbivorous insects with distinct life histories. Results further show that CKs are detected in the highest levels in larvae, reinforcing our hypothesis that CKs accumulating in the mines originate from the insect itself. Presence of bacteria-specific methylthio-CKs is consistent with previous results suggesting that insect bacterial symbionts contribute to the observed phenotype. Our study provides key findings toward the understanding of molecular mechanisms underlying this intricate plant-insect-microbe interaction.
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Affiliation(s)
- Hui Zhang
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France
| | - Antoine Guiguet
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France
- Département de Biologie, École Normale Supérieure de Lyon, Lyon, France
- Department of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Géraldine Dubreuil
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France
| | - Anna Kisiala
- Department of Biology, Trent University, Peterborough, Canada
| | - Peter Andreas
- Department of Biology, Trent University, Peterborough, Canada
| | - R J Neil Emery
- Department of Biology, Trent University, Peterborough, Canada
| | - Elisabeth Huguet
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France
| | - Mélanie Body
- Division of Plant Sciences, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, USA
| | - David Giron
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France
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19
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Lewin GR, Carlos C, Chevrette MG, Horn HA, McDonald BR, Stankey RJ, Fox BG, Currie CR. Evolution and Ecology of Actinobacteria and Their Bioenergy Applications. Annu Rev Microbiol 2017; 70:235-54. [PMID: 27607553 DOI: 10.1146/annurev-micro-102215-095748] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ancient phylum Actinobacteria is composed of phylogenetically and physiologically diverse bacteria that help Earth's ecosystems function. As free-living organisms and symbionts of herbivorous animals, Actinobacteria contribute to the global carbon cycle through the breakdown of plant biomass. In addition, they mediate community dynamics as producers of small molecules with diverse biological activities. Together, the evolution of high cellulolytic ability and diverse chemistry, shaped by their ecological roles in nature, make Actinobacteria a promising group for the bioenergy industry. Specifically, their enzymes can contribute to industrial-scale breakdown of cellulosic plant biomass into simple sugars that can then be converted into biofuels. Furthermore, harnessing their ability to biosynthesize a range of small molecules has potential for the production of specialty biofuels.
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Affiliation(s)
- Gina R Lewin
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Camila Carlos
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Marc G Chevrette
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Heidi A Horn
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706;
| | - Bradon R McDonald
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Robert J Stankey
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Brian G Fox
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726.,Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
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20
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Puigvert M, Guarischi-Sousa R, Zuluaga P, Coll NS, Macho AP, Setubal JC, Valls M. Transcriptomes of Ralstonia solanacearum during Root Colonization of Solanum commersonii. FRONTIERS IN PLANT SCIENCE 2017; 8:370. [PMID: 28373879 PMCID: PMC5357869 DOI: 10.3389/fpls.2017.00370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/02/2017] [Indexed: 05/03/2023]
Abstract
Bacterial wilt of potatoes-also called brown rot-is a devastating disease caused by the vascular pathogen Ralstonia solanacearum that leads to significant yield loss. As in other plant-pathogen interactions, the first contacts established between the bacterium and the plant largely condition the disease outcome. Here, we studied the transcriptome of R. solanacearum UY031 early after infection in two accessions of the wild potato Solanum commersonii showing contrasting resistance to bacterial wilt. Total RNAs obtained from asymptomatic infected roots were deep sequenced and for 4,609 out of the 4,778 annotated genes in strain UY031 were recovered. Only 2 genes were differentially-expressed between the resistant and the susceptible plant accessions, suggesting that the bacterial component plays a minor role in the establishment of disease. On the contrary, 422 genes were differentially expressed (DE) in planta compared to growth on a synthetic rich medium. Only 73 of these genes had been previously identified as DE in a transcriptome of R. solanacearum extracted from infected tomato xylem vessels. Virulence determinants such as the Type Three Secretion System (T3SS) and its effector proteins, motility structures, and reactive oxygen species (ROS) detoxifying enzymes were induced during infection of S. commersonii. On the contrary, metabolic activities were mostly repressed during early root colonization, with the notable exception of nitrogen metabolism, sulfate reduction and phosphate uptake. Several of the R. solanacearum genes identified as significantly up-regulated during infection had not been previously described as virulence factors. This is the first report describing the R. solanacearum transcriptome directly obtained from infected tissue and also the first to analyze bacterial gene expression in the roots, where plant infection takes place. We also demonstrate that the bacterial transcriptome in planta can be studied when pathogen numbers are low by sequencing transcripts from infected tissue avoiding prokaryotic RNA enrichment.
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Affiliation(s)
- Marina Puigvert
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | | | - Paola Zuluaga
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences (CAS)Shanghai, China
| | - João C. Setubal
- Department of Biochemistry, University of São PauloSão Paulo, Brazil
| | - Marc Valls
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
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21
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Dhandapani P, Song J, Novak O, Jameson PE. Infection by Rhodococcus fascians maintains cotyledons as a sink tissue for the pathogen. ANNALS OF BOTANY 2017; 119:841-852. [PMID: 27864224 PMCID: PMC5378184 DOI: 10.1093/aob/mcw202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/31/2016] [Accepted: 08/05/2016] [Indexed: 05/06/2023]
Abstract
Background and Aims Pisum sativum L. (pea) seed is a source of carbohydrate and protein for the developing plant. By studying pea seeds inoculated by the cytokinin-producing bacterium, Rhodococcus fascians , we sought to determine the impact of both an epiphytic (avirulent) strain and a pathogenic strain on source-sink activity within the cotyledons during and following germination. Methods Bacterial spread was monitored microscopically, and real-time reverse transcription-quantitative PCR was used to determine the expression of cytokinin biosynthesis, degradation and response regulator gene family members, along with expression of family members of SWEET , SUT , CWINV and AAP genes - gene families identified initially in pea by transcriptomic analysis. The endogenous cytokinin content was also determined. Key Results The cotyledons infected by the virulent strain remained intact and turned green, while multiple shoots were formed and root growth was reduced. The epiphytic strain had no such marked impact. Isopentenyl adenine was elevated in the cotyledons infected by the virulent strain. Strong expression of RfIPT , RfLOG and RfCKX was detected in the cotyledons infected by the virulent strain throughout the experiment, with elevated expression also observed for PsSWEET , PsSUT and PsINV gene family members. The epiphytic strain had some impact on the expression of these genes, especially at the later stages of reserve mobilization from the cotyledons. Conclusions The pathogenic strain retained the cotyledons as a sink tissue for the pathogen rather than the cotyledon converting completely to a source tissue for the germinating plant. We suggest that the interaction of cytokinins, CWINVs and SWEETs may lead to the loss of apical dominance and the appearance of multiple shoots.
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Affiliation(s)
- Pragatheswari Dhandapani
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Jiancheng Song
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
- School of Life Sciences, Yantai University, Yantai 264005, China
| | - Ondrej Novak
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany CAS & Faculty of Science of Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Paula E. Jameson
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
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22
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van Tol HM, Amin SA, Armbrust EV. Ubiquitous marine bacterium inhibits diatom cell division. THE ISME JOURNAL 2017; 11:31-42. [PMID: 27623332 PMCID: PMC5315476 DOI: 10.1038/ismej.2016.112] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 11/09/2022]
Abstract
Intricate relationships between microorganisms structure the exchange of molecules between taxa, driving their physiology and evolution. On a global scale, this molecular trade is an integral component of biogeochemical cycling. As important microorganisms in the world's oceans, diatoms and bacteria have a large impact on marine biogeochemistry. Here, we describe antagonistic effects of the globally distributed flavobacterium Croceibacter atlanticus on a phylogenetically diverse group of diatoms. We used the model diatom Thalassiosira pseudonana to study the antagonistic impact in more detail. In co-culture, C. atlanticus attaches to T. pseudonana and inhibits cell division, inducing diatom cells to become larger and increase in chlorophyll a fluorescence. These changes could be explained by an absence of cytokinesis that causes individual T. pseudonana cells to elongate, accumulate more plastids and become polyploid. These morphological changes could benefit C. atlanticus by augmenting the colonizable surface area of the diatom, its photosynthetic capabilities and possibly its metabolic secretions.
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Affiliation(s)
- Helena M van Tol
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Shady A Amin
- Department of Chemistry, New York University Abu Dhabi, Abu Dhabi, UAE
- Department of Biology, New York University Abu Dhabi, Abu Dhabi, UAE
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23
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Almabruk KH, Chang JH, Mahmud T. Total Synthesis of (±)-Isoperbergins and Correction of the Chemical Structure of Perbergin. JOURNAL OF NATURAL PRODUCTS 2016; 79:2391-2396. [PMID: 27588436 DOI: 10.1021/acs.jnatprod.6b00621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
On the basis of its reported chemical structure, perbergin, a Rhodococcus fascians virulence quencher from the bark of Dalbergia pervillei, and its isomer were synthesized in nine steps with a 13.5% yield. However, the NMR spectra of the synthetic products were inconsistent with those reported in the literature. Re-evaluation of the 1D and 2D NMR spectra of the natural product perbergin revealed that the geranyl moiety of this compound is located at C-6 and has an E-configuration, instead of the reported C-8 geranylation with a Z-configuration. Interestingly, the synthetic isoperbergins demonstrated good antibacterial activity against R. fascians, Mycobacterium smegmatis, and Staphylococcus aureus, but not against the Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli.
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Affiliation(s)
- Khaled H Almabruk
- Department of Pharmaceutical Sciences, Oregon State University , Corvallis, Oregon 97331-3507, United States
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University , Corvallis, Oregon 97331-2902, United States
| | - Taifo Mahmud
- Department of Pharmaceutical Sciences, Oregon State University , Corvallis, Oregon 97331-3507, United States
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Seo H, Kim S, Sagong HY, Son HF, Jin KS, Kim IK, Kim KJ. Structural basis for cytokinin production by LOG from Corynebacterium glutamicum. Sci Rep 2016; 6:31390. [PMID: 27507425 PMCID: PMC4979012 DOI: 10.1038/srep31390] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/19/2016] [Indexed: 01/22/2023] Open
Abstract
"Lonely guy" (LOG) has been identified as a cytokinin-producing enzyme in plants and plant-interacting fungi. The gene product of Cg2612 from the soil-dwelling bacterium Corynebacterium glutamicum was annotated as an LDC. However, the facts that C. glutamicum lacks an LDC and Cg2612 has high amino acid similarity with LOG proteins suggest that Cg2612 is possibly an LOG protein. To investigate the function of Cg2612, we determined its crystal structure at a resolution of 2.3 Å. Cg2612 functions as a dimer and shows an overall structure similar to other known LOGs, such as LOGs from Arabidopsis thaliana (AtLOG), Claviceps purpurea (CpLOG), and Mycobacterium marinum (MmLOG). Cg2612 also contains a "PGGXGTXXE" motif that contributes to the formation of an active site similar to other LOGs. Moreover, biochemical studies on Cg2612 revealed that the protein has phosphoribohydrolase activity but not LDC activity. Based on these structural and biochemical studies, we propose that Cg2612 is not an LDC family enzyme, but instead belongs to the LOG family. In addition, the prenyl-binding site of Cg2612 (CgLOG) comprised residues identical to those seen in AtLOG and CpLOG, albeit dissimilar to those in MmLOG. The work provides structural and functional implications for LOG-like proteins from other microorganisms.
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Affiliation(s)
- Hogyun Seo
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Sangwoo Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
- School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea
| | - Hye-Young Sagong
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Hyeoncheol Francis Son
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Kyeong Sik Jin
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Jigok-ro 80, Pohang, Kyungbuk 790-784, Korea
| | - Il-Kwon Kim
- Biopoecess Research Depart. R&D Center, DAESANG Corp., Icheon-si, Gyeonggi-do, 467-810, Republic of Korea
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
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25
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Stamler RA, Vereecke D, Zhang Y, Schilkey F, Devitt N, Randall JJ. Complete Genome and Plasmid Sequences for Rhodococcus fascians D188 and Draft Sequences for Rhodococcus Isolates PBTS 1 and PBTS 2. GENOME ANNOUNCEMENTS 2016; 4:e00495-16. [PMID: 27284129 PMCID: PMC4901220 DOI: 10.1128/genomea.00495-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 04/28/2016] [Indexed: 11/20/2022]
Abstract
Rhodococcus fascians, a phytopathogen that alters plant development, inflicts significant losses in plant production around the world. We report here the complete genome sequence of R. fascians D188, a well-characterized model isolate, and Rhodococcus species PBTS (pistachio bushy top syndrome) 1 and 2, which were shown to be responsible for a disease outbreak in pistachios.
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Affiliation(s)
- Rio A Stamler
- Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, New Mexico, USA
| | - Danny Vereecke
- Department of Applied Biosciences, Ghent University, Ghent, Belgium
| | - Yucheng Zhang
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Faye Schilkey
- National Center for Genome Resources, Santa Fe, New Mexico, USA
| | - Nico Devitt
- National Center for Genome Resources, Santa Fe, New Mexico, USA
| | - Jennifer J Randall
- Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, New Mexico, USA
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26
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Mining the genome of Rhodococcus fascians, a plant growth-promoting bacterium gone astray. N Biotechnol 2016; 33:706-717. [PMID: 26877150 DOI: 10.1016/j.nbt.2016.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022]
Abstract
Rhodococcus fascians is a phytopathogenic Gram-positive Actinomycete with a very broad host range encompassing especially dicotyledonous herbaceous perennials, but also some monocots, such as the Liliaceae and, recently, the woody crop pistachio. The pathogenicity of R. fascians strain D188 is known to be encoded by the linear plasmid pFiD188 and to be dictated by its capacity to produce a mixture of cytokinins. Here, we show that D188-5, the nonpathogenic plasmid-free derivative of the wild-type strain D188 actually has a plant growth-promoting effect. With the availability of the genome sequence of R. fascians, the chromosome of strain D188 was mined for putative plant growth-promoting functions and the functionality of some of these activities was tested. This analysis together with previous results suggests that the plant growth-promoting activity of R. fascians is due to production of plant growth modulators, such as auxin and cytokinin, combined with degradation of ethylene through 1-amino-cyclopropane-1-carboxylic acid deaminase. Moreover, R. fascians has several functions that could contribute to efficient colonization and competitiveness, but there is little evidence for a strong impact on plant nutrition. Possibly, the plant growth promotion encoded by the D188 chromosome is imperative for the epiphytic phase of the life cycle of R. fascians and prepares the plant to host the bacteria, thus ensuring proper continuation into the pathogenic phase.
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27
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Giron D, Huguet E, Stone GN, Body M. Insect-induced effects on plants and possible effectors used by galling and leaf-mining insects to manipulate their host-plant. JOURNAL OF INSECT PHYSIOLOGY 2016; 84:70-89. [PMID: 26723843 DOI: 10.1016/j.jinsphys.2015.12.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 05/04/2023]
Abstract
Gall-inducing insects are iconic examples in the manipulation and reprogramming of plant development, inducing spectacular morphological and physiological changes of host-plant tissues within which the insect feeds and grows. Despite decades of research, effectors involved in gall induction and basic mechanisms of gall formation remain unknown. Recent research suggests that some aspects of the plant manipulation shown by gall-inducers may be shared with other insect herbivorous life histories. Here, we illustrate similarities and contrasts by reviewing current knowledge of metabolic and morphological effects induced on plants by gall-inducing and leaf-mining insects, and ask whether leaf-miners can also be considered to be plant reprogrammers. We review key plant functions targeted by various plant reprogrammers, including plant-manipulating insects and nematodes, and functionally characterize insect herbivore-derived effectors to provide a broader understanding of possible mechanisms used in host-plant manipulation. Consequences of plant reprogramming in terms of ecology, coevolution and diversification of plant-manipulating insects are also discussed.
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Affiliation(s)
- David Giron
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Parc Grandmont, 37200 Tours, France.
| | - Elisabeth Huguet
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Parc Grandmont, 37200 Tours, France
| | - Graham N Stone
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom
| | - Mélanie Body
- Division of Plant Sciences, Christopher S. Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, United States
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28
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Zhang H, Dugé de Bernonville T, Body M, Glevarec G, Reichelt M, Unsicker S, Bruneau M, Renou JP, Huguet E, Dubreuil G, Giron D. Leaf-mining by Phyllonorycter blancardella reprograms the host-leaf transcriptome to modulate phytohormones associated with nutrient mobilization and plant defense. JOURNAL OF INSECT PHYSIOLOGY 2016; 84:114-127. [PMID: 26068004 DOI: 10.1016/j.jinsphys.2015.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 05/05/2023]
Abstract
Phytohormones have long been hypothesized to play a key role in the interactions between plant-manipulating organisms and their host-plants such as insect-plant interactions that lead to gall or 'green-islands' induction. However, mechanistic understanding of how phytohormones operate in these plant reconfigurations is lacking due to limited information on the molecular and biochemical phytohormonal modulation following attack by plant-manipulating insects. In an attempt to fill this gap, the present study provides an extensive characterization of how the leaf-miner Phyllonorycter blancardella modulates the major phytohormones and the transcriptional activity of plant cells in leaves of Malus domestica. We show here, that cytokinins strongly accumulate in mined tissues despite a weak expression of plant cytokinin-related genes. Leaf-mining is also associated with enhanced biosynthesis of jasmonic acid precursors but not the active form, a weak alteration of the salicylic acid pathway and a clear inhibition of the abscisic acid pathway. Our study consolidates previous results suggesting that insects may produce and deliver cytokinins to the plant as a strategy to manipulate the physiology of the leaf to create a favorable nutritional environment. We also demonstrate that leaf-mining by P. blancardella leads to a strong reprogramming of the plant phytohormonal balance associated with increased nutrient mobilization, inhibition of leaf senescence and mitigation of plant direct and indirect defense.
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Affiliation(s)
- Hui Zhang
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France.
| | - Thomas Dugé de Bernonville
- Laboratoire Biologie Végétale et Biomolécules, EA 2106, Université François-Rabelais de Tours, Tours, France.
| | - Mélanie Body
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France.
| | - Gaëlle Glevarec
- Laboratoire Biologie Végétale et Biomolécules, EA 2106, Université François-Rabelais de Tours, Tours, France.
| | - Michael Reichelt
- Department of Biochemistry, Max-Planck-Institute for Chemical Ecology, Jena, Germany.
| | - Sybille Unsicker
- Department of Biochemistry, Max-Planck-Institute for Chemical Ecology, Jena, Germany.
| | - Maryline Bruneau
- Institut de Recherche en Horticulture et Semences, UMR 1345, INRA, SFR 4207 QuaSaV, Beaucouzé, France.
| | - Jean-Pierre Renou
- Institut de Recherche en Horticulture et Semences, UMR 1345, INRA, SFR 4207 QuaSaV, Beaucouzé, France.
| | - Elisabeth Huguet
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France.
| | - Géraldine Dubreuil
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France.
| | - David Giron
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Université François-Rabelais de Tours, Tours, France.
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Stamler RA, Kilcrease J, Kallsen C, Fichtner EJ, Cooke P, Heerema RJ, Randall JJ. First Report of Rhodococcus Isolates Causing Pistachio Bushy Top Syndrome on 'UCB-1' Rootstock in California and Arizona. PLANT DISEASE 2015; 99:1468-1476. [PMID: 30695969 DOI: 10.1094/pdis-12-14-1340-re] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
'UCB-1' (Pistacia atlantica × Pistacia integerrima) rootstock is a hybrid cultivar widely used by the U.S. pistachio industry. In the last three years, a large number of micropropagated UCB-1 pistachio rootstocks planted in California and Arizona orchards exhibited shortened internodes, stunted growth, swollen lateral buds, bushy/bunchy growth, stem galls with multiple buds, and twisted roots with minimal lateral branching. Field T-budding success in affected orchards was reduced to approximately 30% with unusual bark cracking often observed around the bud-union. The percentage of abnormal rootstocks within affected orchards varied from 10 to 90%. We have termed the cumulative symptoms "pistachio bushy top syndrome" (PBTS) to describe these affected trees. Two isolates, both containing virulence factors from the phytopathogen Rhodococcus fascians, were identified on symptomatic trees in field and nursery samples. Micropropagated UCB-1 trees inoculated with the Rhodococcus isolates exhibited stunted growth, shortened internode length, swollen lateral buds, sylleptic branching, and differences in root morphology, compared with control UCB-1 trees. To our knowledge, this is the first report of Rhodococcus isolates, related to Rhodococcus fascians, causing disease on a commercial tree crop and the results presented indicate that this organism is responsible at least in part for PBTS in California and Arizona.
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Affiliation(s)
- Rio A Stamler
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
| | - James Kilcrease
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
| | - Craig Kallsen
- University of California, Cooperative Extension, Bakersfield, CA 93307
| | | | - Peter Cooke
- Core University Resource Laboratory, New Mexico State University, Las Cruces, NM 88003
| | | | - Jennifer J Randall
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
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30
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Stes E, Depuydt S, De Keyser A, Matthys C, Audenaert K, Yoneyama K, Werbrouck S, Goormachtig S, Vereecke D. Strigolactones as an auxiliary hormonal defence mechanism against leafy gall syndrome in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5123-34. [PMID: 26136271 PMCID: PMC4513927 DOI: 10.1093/jxb/erv309] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Leafy gall syndrome is the consequence of modified plant development in response to a mixture of cytokinins secreted by the biotrophic actinomycete Rhodococcus fascians. The similarity of the induced symptoms with the phenotype of plant mutants defective in strigolactone biosynthesis and signalling prompted an evaluation of the involvement of strigolactones in this pathology. All tested strigolactone-related Arabidopsis thaliana mutants were hypersensitive to R. fascians. Moreover, treatment with the synthetic strigolactone mixture GR24 and with the carotenoid cleavage dioxygenase inhibitor D2 illustrated that strigolactones acted as antagonistic compounds that restricted the morphogenic activity of R. fascians. Transcript profiling of the MORE AXILLARY GROWTH1 (MAX1), MAX2, MAX3, MAX4, and BRANCHED1 (BRC1) genes in the wild-type Columbia-0 accession and in different mutant backgrounds revealed that upregulation of strigolactone biosynthesis genes was triggered indirectly by the bacterial cytokinins via host-derived auxin and led to the activation of BRC1 expression, inhibiting the outgrowth of the newly developing shoots, a typical hallmark of leafy gall syndrome. Taken together, these data support the emerging insight that balances are critical for optimal leafy gall development: the long-lasting biotrophic interaction is possible only because the host activates a set of countermeasures-including the strigolactone response-in reaction to bacterial cytokinins to constrain the activity of R. fascians.
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Affiliation(s)
- Elisabeth Stes
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium Department of Medical Protein Research, VIB, 9000 Gent, Belgium Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Stephen Depuydt
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium Ghent University Global Campus, Incheon 406-840, Republic of Korea
| | - Annick De Keyser
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Cedrick Matthys
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Kris Audenaert
- Department of Applied Biosciences, Ghent University, 9000 Gent, Belgium
| | - Koichi Yoneyama
- Center for Bioscience Research & Education, Utsunomiya University, Utsunomiya 321-8505, Japan
| | - Stefaan Werbrouck
- Department of Applied Biosciences, Ghent University, 9000 Gent, Belgium
| | - Sofie Goormachtig
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Danny Vereecke
- Department of Applied Biosciences, Ghent University, 9000 Gent, Belgium
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31
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Laffont C, Rey T, André O, Novero M, Kazmierczak T, Debellé F, Bonfante P, Jacquet C, Frugier F. The CRE1 cytokinin pathway is differentially recruited depending on Medicago truncatula root environments and negatively regulates resistance to a pathogen. PLoS One 2015; 10:e0116819. [PMID: 25562779 PMCID: PMC4285552 DOI: 10.1371/journal.pone.0116819] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 12/16/2014] [Indexed: 01/06/2023] Open
Abstract
Cytokinins are phytohormones that regulate many developmental and environmental responses. The Medicago truncatula cytokinin receptor MtCRE1 (Cytokinin Response 1) is required for the nitrogen-fixing symbiosis with rhizobia. As several cytokinin signaling genes are modulated in roots depending on different biotic and abiotic conditions, we assessed potential involvement of this pathway in various root environmental responses. Phenotyping of cre1 mutant roots infected by the Gigaspora margarita arbuscular mycorrhizal (AM) symbiotic fungus, the Aphanomyces euteiches root oomycete, or subjected to an abiotic stress (salt), were carried out. Detailed histological analysis and quantification of cre1 mycorrhized roots did not reveal any detrimental phenotype, suggesting that MtCRE1 does not belong to the ancestral common symbiotic pathway shared by rhizobial and AM symbioses. cre1 mutants formed an increased number of emerged lateral roots compared to wild-type plants, a phenotype which was also observed under non-stressed conditions. In response to A. euteiches, cre1 mutants showed reduced disease symptoms and an increased plant survival rate, correlated to an enhanced formation of lateral roots, a feature previously linked to Aphanomyces resistance. Overall, we showed that the cytokinin CRE1 pathway is not only required for symbiotic nodule organogenesis but also affects both root development and resistance to abiotic and biotic environmental stresses.
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Affiliation(s)
- Carole Laffont
- CNRS, Institut des Sciences du Végétal (ISV), avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Thomas Rey
- Université de Toulouse, UPS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Olivier André
- Université de Toulouse, UPS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Mara Novero
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, 10125 Torino, Italy
| | - Théophile Kazmierczak
- CNRS, Institut des Sciences du Végétal (ISV), avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Frédéric Debellé
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, F-31326, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, F-31326, France
| | - Paola Bonfante
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, 10125 Torino, Italy
| | - Christophe Jacquet
- Université de Toulouse, UPS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Florian Frugier
- CNRS, Institut des Sciences du Végétal (ISV), avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
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32
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Creason AL, Davis EW, Putnam ML, Vandeputte OM, Chang JH. Use of whole genome sequences to develop a molecular phylogenetic framework for Rhodococcus fascians and the Rhodococcus genus. FRONTIERS IN PLANT SCIENCE 2014; 5:406. [PMID: 25237311 PMCID: PMC4154481 DOI: 10.3389/fpls.2014.00406] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 07/30/2014] [Indexed: 06/03/2023]
Abstract
The accurate diagnosis of diseases caused by pathogenic bacteria requires a stable species classification. Rhodococcus fascians is the only documented member of its ill-defined genus that is capable of causing disease on a wide range of agriculturally important plants. Comparisons of genome sequences generated from isolates of Rhodococcus associated with diseased plants revealed a level of genetic diversity consistent with them representing multiple species. To test this, we generated a tree based on more than 1700 homologous sequences from plant-associated isolates of Rhodococcus, and obtained support from additional approaches that measure and cluster based on genome similarities. Results were consistent in supporting the definition of new Rhodococcus species within clades containing phytopathogenic members. We also used the genome sequences, along with other rhodococcal genome sequences to construct a molecular phylogenetic tree as a framework for resolving the Rhodococcus genus. Results indicated that Rhodococcus has the potential for having 20 species and also confirmed a need to revisit the taxonomic groupings within Rhodococcus.
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Affiliation(s)
- Allison L. Creason
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallis, OR, USA
- Molecular and Cellular Biology Program, Oregon State UniversityCorvallis, OR, USA
| | - Edward W. Davis
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallis, OR, USA
- Molecular and Cellular Biology Program, Oregon State UniversityCorvallis, OR, USA
| | - Melodie L. Putnam
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallis, OR, USA
| | - Olivier M. Vandeputte
- Laboratoire de Biotechnologie Vegetale, Universite Libre de BruxellesGosselies, Belgium
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallis, OR, USA
- Molecular and Cellular Biology Program, Oregon State UniversityCorvallis, OR, USA
- Center for Genome Research and Biocomputing, Oregon State UniversityCorvallis, OR, USA
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33
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Evaluating Insect-Microbiomes at the Plant-Insect Interface. J Chem Ecol 2014; 40:836-47. [DOI: 10.1007/s10886-014-0475-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/17/2014] [Accepted: 06/20/2014] [Indexed: 12/17/2022]
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34
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Creason AL, Vandeputte OM, Savory EA, Davis EW, Putnam ML, Hu E, Swader-Hines D, Mol A, Baucher M, Prinsen E, Zdanowska M, Givan SA, Jaziri ME, Loper JE, Mahmud T, Chang JH. Analysis of genome sequences from plant pathogenic Rhodococcus reveals genetic novelties in virulence loci. PLoS One 2014; 9:e101996. [PMID: 25010934 PMCID: PMC4092121 DOI: 10.1371/journal.pone.0101996] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 06/12/2014] [Indexed: 12/19/2022] Open
Abstract
Members of Gram-positive Actinobacteria cause economically important diseases to plants. Within the Rhodococcus genus, some members can cause growth deformities and persist as pathogens on a wide range of host plants. The current model predicts that phytopathogenic isolates require a cluster of three loci present on a linear plasmid, with the fas operon central to virulence. The Fas proteins synthesize, modify, and activate a mixture of growth regulating cytokinins, which cause a hormonal imbalance in plants, resulting in abnormal growth. We sequenced and compared the genomes of 20 isolates of Rhodococcus to gain insights into the mechanisms and evolution of virulence in these bacteria. Horizontal gene transfer was identified as critical but limited in the scale of virulence evolution, as few loci are conserved and exclusive to phytopathogenic isolates. Although the fas operon is present in most phytopathogenic isolates, it is absent from phytopathogenic isolate A21d2. Instead, this isolate has a horizontally acquired gene chimera that encodes a novel fusion protein with isopentyltransferase and phosphoribohydrolase domains, predicted to be capable of catalyzing and activating cytokinins, respectively. Cytokinin profiling of the archetypal D188 isolate revealed only one activate cytokinin type that was specifically synthesized in a fas-dependent manner. These results suggest that only the isopentenyladenine cytokinin type is synthesized and necessary for Rhodococcus phytopathogenicity, which is not consistent with the extant model stating that a mixture of cytokinins is necessary for Rhodococcus to cause leafy gall symptoms. In all, data indicate that only four horizontally acquired functions are sufficient to confer the trait of phytopathogenicity to members of the genetically diverse clade of Rhodococcus.
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Affiliation(s)
- Allison L. Creason
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Olivier M. Vandeputte
- Laboratoire de Biotechnologie Vegetale, Universite Libre de Bruxelles, Gosselies, Belgium
| | - Elizabeth A. Savory
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Edward W. Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, United States of America
| | - Melodie L. Putnam
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Erdong Hu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - David Swader-Hines
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Adeline Mol
- Laboratoire de Biotechnologie Vegetale, Universite Libre de Bruxelles, Gosselies, Belgium
| | - Marie Baucher
- Laboratoire de Biotechnologie Vegetale, Universite Libre de Bruxelles, Gosselies, Belgium
| | - Els Prinsen
- University of Antwerp, Department of Biology, Laboratory of Plant Growth and Development, Antwerp, Belgium
| | - Magdalena Zdanowska
- University of Antwerp, Department of Biology, Laboratory of Plant Growth and Development, Antwerp, Belgium
| | - Scott A. Givan
- Informatics Research Core Facility, University of Missouri, Columbia, Missouri, United States of America
| | - Mondher El Jaziri
- Laboratoire de Biotechnologie Vegetale, Universite Libre de Bruxelles, Gosselies, Belgium
| | - Joyce E. Loper
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, United States of America
- United States Department of Agriculture, Agricultural Research Service, Horticultural Crops Research Laboratory, Corvallis, Oregon, United States of America
| | - Taifo Mahmud
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, United States of America
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, United States of America
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon, United States of America
- * E-mail:
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Cytokinin-induced phenotypes in plant-insect interactions: learning from the bacterial world. J Chem Ecol 2014; 40:826-35. [PMID: 24944001 DOI: 10.1007/s10886-014-0466-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 01/09/2023]
Abstract
Recently, a renewed interest in cytokinins (CKs) has allowed the characterization of these phytohormones as key regulatory molecules in plant biotic interactions. They have been proved to be instrumental in microbe- and insect-mediated plant phenotypes that can be either beneficial or detrimental for the host-plant. In parallel, insect endosymbiotic bacteria have emerged as key players in plant-insect interactions mediating directly or indirectly fundamental aspects of insect nutrition, such as insect feeding efficiency or the ability to manipulate plant physiology to overcome food nutritional imbalances. However, mechanisms that regulate CK production and the role played by insects and their endosymbionts remain largely unknown. Against this backdrop, studies on plant-associated bacteria have revealed fascinating and complex molecular mechanisms that lead to the production of bacterial CKs and the modulation of plant-borne CKs which ultimately result in profound metabolic and morphological plant modifications. This review highlights major strategies used by plant-associated bacteria that impact the CK homeostasis of their host-plant, to raise parallels with strategies used by phytophagous insects and to discuss the possible role played by endosymbiotic bacteria in these CK-mediated plant phenotypes. We hypothesize that insects employ a CK-mix production strategy that manipulates the phytohormonal balance of their host-plant and overtakes plant gene expression causing a metabolic and morphological habitat modification. In addition, insect endosymbiotic bacteria may prove to be instrumental in these manipulations through the production of bacterial CKs, including specific forms that challenge the CK-degrading capacity of the plant (thus ensuring persistent effects) and the CK-mediated plant defenses.
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Tarkowski P, Vereecke D. Threats and opportunities of plant pathogenic bacteria. Biotechnol Adv 2013; 32:215-29. [PMID: 24216222 DOI: 10.1016/j.biotechadv.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/22/2013] [Accepted: 11/03/2013] [Indexed: 02/08/2023]
Abstract
Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae.
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Affiliation(s)
- Petr Tarkowski
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-78371 Olomouc, Czech Republic.
| | - Danny Vereecke
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, BE-9000 Ghent, Belgium.
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Nacoulma AP, Megalizzi V, Pottier LR, De Lorenzi M, Thoret S, Dubois J, Vandeputte OM, Duez P, Vereecke D, Jaziri ME. Potent antiproliferative cembrenoids accumulate in tobacco upon infection with Rhodococcus fascians and trigger unusual microtubule dynamics in human glioblastoma cells. PLoS One 2013; 8:e77529. [PMID: 24167576 PMCID: PMC3805576 DOI: 10.1371/journal.pone.0077529] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/10/2013] [Indexed: 12/26/2022] Open
Abstract
AIMS Though plant metabolic changes are known to occur during interactions with bacteria, these were rarely challenged for pharmacologically active compounds suitable for further drug development. Here, the occurrence of specific chemicals with antiproliferative activity against human cancer cell lines was evidenced in hyperplasia (leafy galls) induced when plants interact with particular phytopathogens, such as the Actinomycete Rhodococcus fascians. METHODS We examined leafy galls fraction F3.1.1 on cell proliferation, cell division and cytoskeletal disorganization of human cancer cell lines using time-lapse videomicroscopy imaging, combined with flow cytometry and immunofluorescence analysis. We determined the F3.1.1-fraction composition by gas chromatography coupled to mass spectrometry. RESULTS The leafy galls induced on tobacco by R. fascians yielded fraction F3.1.1 which inhibited proliferation of glioblastoma U373 cells with an IC50 of 4.5 µg/mL, F.3.1.1 was shown to increase cell division duration, cause nuclear morphological deformations and cell enlargement, and, at higher concentrations, karyokinesis defects leading to polyploidization and apoptosis. F3.1.1 consisted of a mixture of isomers belonging to the cembrenoids. The cellular defects induced by F3.1.1 were caused by a peculiar cytoskeletal disorganization, with the occurrence of fragmented tubulin and strongly organized microtubule aggregates within the same cell. Colchicine, paclitaxel, and cembrene also affected U373 cell proliferation and karyokinesis, but the induced microtubule rearrangement was very different from that provoked by F3.1.1. Altogether our data indicate that the cembrenoid isomers in F3.1.1 have a unique mode of action and are able to simultaneously modulate microtubule polymerization and stability.
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Affiliation(s)
- Aminata P. Nacoulma
- Laboratoire de Toxicologie, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Veronique Megalizzi
- Laboratoire de Toxicologie, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Laurent R. Pottier
- Laboratoire de Pharmacognosie, de Bromatologie et de Nutrition Humaine, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Manuela De Lorenzi
- Laboratoire de Toxicologie, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Sylviane Thoret
- Institut de Chimie des Substances Naturelles, Centre national de la recherche scientifique Unité PR 2301, Gif-sur-Yvette, France
| | - Joëlle Dubois
- Institut de Chimie des Substances Naturelles, Centre national de la recherche scientifique Unité PR 2301, Gif-sur-Yvette, France
| | - Olivier M. Vandeputte
- Laboratoire de Biotechnologie Végétale, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Pierre Duez
- Laboratoire de Pharmacognosie, de Bromatologie et de Nutrition Humaine, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Danny Vereecke
- Department of Plant Production, University College Ghent, Ghent University, Gent, Belgium
| | - Mondher El Jaziri
- Laboratoire de Biotechnologie Végétale, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium
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Nabity PD, Haus MJ, Berenbaum MR, DeLucia EH. Leaf-galling phylloxera on grapes reprograms host metabolism and morphology. Proc Natl Acad Sci U S A 2013; 110:16663-8. [PMID: 24067657 PMCID: PMC3799386 DOI: 10.1073/pnas.1220219110] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Endoparasitism by gall-forming insects dramatically alters the plant phenotype by altering growth patterns and modifying plant organs in ways that appear to directly benefit the gall former. Because these morphological and physiological changes are linked to the presence of the insect, the induced phenotype is said to function as an extension of the parasite, albeit by unknown mechanisms. Here we report the gall-forming aphid-like parasite phylloxera, Daktulosphaira vitifoliae, induces stomata on the adaxial surface of grape leaves where stomata typically do not occur. We characterized the function of the phylloxera-induced stomata by tracing transport of assimilated carbon. Because induction of stomata suggests a significant manipulation of primary metabolism, we also characterized the gall transcriptome to infer the level of global reconfiguration of primary metabolism and the subsequent changes in downstream secondary metabolism. Phylloxera feeding induced stomata formation in proximity to the insect and promoted the assimilation and importation of carbon into the gall. Gene expression related to water, nutrient, and mineral transport; glycolysis; and fermentation increased in leaf-gall tissues. This shift from an autotrophic to a heterotrophic profile occurred concurrently with decreased gene expression for nonmevalonate and terpenoid synthesis and increased gene expression in shikimate and phenylpropanoid biosynthesis, secondary metabolite systems that alter defense status in grapes. These functional insect-induced stomata thus comprise part of an extended phenotype, whereby D. vitifoliae globally reprograms grape leaf development to alter patterns of primary metabolism, nutrient mobilization, and defense investment in favor of the galling habit.
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Affiliation(s)
- Paul D. Nabity
- Departments of Plant Biology and
- Institute of Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | | | - May R. Berenbaum
- Entomology, and
- Institute of Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | - Evan H. DeLucia
- Departments of Plant Biology and
- Institute of Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, IL 61801
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39
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Kisiala A, Laffont C, Emery RJN, Frugier F. Bioactive cytokinins are selectively secreted by Sinorhizobium meliloti nodulating and nonnodulating strains. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1225-31. [PMID: 24001254 DOI: 10.1094/mpmi-02-13-0054-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Bacteria present in the rhizosphere of plants often synthesize phytohormones, and these signals can consequently affect root system development. In legumes, plants adapt to nitrogen starvation by forming lateral roots as well as a new organ, the root nodule, following a symbiotic interaction with bacteria collectively referred to as rhizobia. As cytokinin (CK) phytohormones were shown to be necessary and sufficient to induce root nodule organogenesis, the relevance of CK production by symbiotic rhizobia was questioned. In this study, we analyzed quantitatively, by liquid chromatography-tandem mass spectrometry, the production of 25 forms of CK in nine rhizobia strains belonging to four different species. All bacterial strains were able to synthesize a mix of CK, and bioactive forms of CK, such as iP, were notably found to be secreted in bacterial culture supernatants. Use of a mutant affected in extracellular polysaccharide (EPS) production revealed a negative correlation of EPS production with the ability to secrete CK. In addition, analysis of a nonnodulating Sinorhizobium meliloti strain revealed a similar pattern of CK production and secretion when compared with a related nodulating strain. This indicates that bacterially produced CK are not sufficient to induce symbiotic nodulation.
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40
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Nacoulma AP, Vandeputte OM, De Lorenzi M, El Jaziri M, Duez P. Metabolomic-based study of the leafy gall, the ecological niche of the phytopathogen Rhodococcus fascians, as a potential source of bioactive compounds. Int J Mol Sci 2013; 14:12533-49. [PMID: 23771021 PMCID: PMC3709798 DOI: 10.3390/ijms140612533] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/21/2013] [Accepted: 06/04/2013] [Indexed: 01/27/2023] Open
Abstract
Leafy gall is a plant hyperplasia induced upon Rhodococcus fascians infection. Previously, by genomic and transcriptomic analysis, it has been reported that, at the early stage of symptom development, both primary and secondary metabolisms are modified. The present study is based on the hypothesis that fully developed leafy gall, could represent a potential source of new bioactive compounds. Therefore, non-targeted metabolomic analysis of aqueous and chloroform extracts of leafy gall and non-infected tobacco was carried out by 1H-NMR coupled to principal component analysis (PCA) and orthogonal projections to latent structures-discriminant analysis (OPLS-DA). Polar metabolite profiling reflects modifications mainly in the primary metabolites and in some polyphenolics. In contrast, main modifications occurring in non-polar metabolites concern secondary metabolites, and gas chromatography and mass spectrometry (GC-MS) evidenced alterations in diterpenoids family. Analysis of crude extracts of leafy galls and non-infected tobacco leaves exhibited a distinct antiproliferative activity against all four tested human cancer cell lines. A bio-guided fractionation of chloroformic crude extract yield to semi-purified fractions, which inhibited proliferation of glioblastoma U373 cells with IC50 between 14.0 and 2.4 µg/mL. Discussion is focused on the consequence of these metabolic changes, with respect to plant defense mechanisms following infection. Considering the promising role of diterpenoid family as bioactive compounds, leafy gall may rather be a propitious source for drug discovery.
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Affiliation(s)
- Aminata P. Nacoulma
- Laboratory of Toxicology, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/1, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
| | - Olivier M. Vandeputte
- Laboratory of Plant Biotechnology, Faculty of Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium; E-Mails: (O.M.V.); (M.E.J.)
| | - Manuella De Lorenzi
- Laboratory of Toxicology, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/1, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
| | - Mondher El Jaziri
- Laboratory of Plant Biotechnology, Faculty of Sciences, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium; E-Mails: (O.M.V.); (M.E.J.)
| | - Pierre Duez
- Laboratory of Pharmacognosy, Bromatology and Human Nutrition, Faculty of Pharmacy, Université Libre de Bruxelles, CP 205/9, Boulevard du Triomphe, Brussels B-1050, Belgium; E-Mail:
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41
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Stes E, Francis I, Pertry I, Dolzblasz A, Depuydt S, Vereecke D. The leafy gall syndrome induced byRhodococcus fascians. FEMS Microbiol Lett 2013; 342:187-94. [DOI: 10.1111/1574-6968.12119] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 12/20/2022] Open
Affiliation(s)
- Elisabeth Stes
- Department of Plant Biotechnology and Bioinformatics; Ghent University; Gent; Belgium
| | - Isolde Francis
- Department of Plant Biotechnology and Bioinformatics; Ghent University; Gent; Belgium
| | - Ine Pertry
- Department of Plant Biotechnology and Bioinformatics; Ghent University; Gent; Belgium
| | - Alicja Dolzblasz
- Institute of Experimental Biology; Department of Plant Developmental Biology; Wrocław University; Wrocław; Poland
| | | | - Danny Vereecke
- Department of Plant Production; University College Ghent; Ghent University; Gent; Belgium
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42
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Serdani M, Curtis M, Miller ML, Kraus J, Putnam ML. Loop-Mediated Isothermal Amplification and Polymerase Chain Reaction Methods for Specific and Rapid Detection of Rhodococcus fascians. PLANT DISEASE 2013; 97:517-529. [PMID: 30722233 DOI: 10.1094/pdis-02-12-0214-re] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rhodococcus fascians is a phytopathogenic actinobacterium which causes leafy galls and other plant distortions that result in economically significant losses to nurseries producing ornamental plants. Traditional assays for detection and identification are time-consuming and laborious. We developed a rapid polymerase chain reaction (PCR) diagnostic assay based on two primer pairs, p450 and fas, which target the fasA and fasD genes, respectively, that are essential for pathogenicity. We also developed a faster, more convenient, loop-mediated isothermal amplification (LAMP) assay targeting the fasR gene, which regulates expression of virulence genes. Both assays were evaluated for sensitivity and specificity in vitro and in planta. The p450 and fas primers amplified DNA only from pure cultures of pathogenic reference isolates of R. fascians. Nonpathogenic isolates and 51 other plant-associated bacteria were not amplified. The PCR primers correctly detected pathogenic R. fascians from 73 of 75 (97%) bacterial strains isolated from naturally infected plants. The PCR assay correctly discriminated between pathogenic R. fascians and other bacteria in 132 of 139 (95%) naturally infected plants, and in 34 of 34 (100%) artificially inoculated plants. The fas primers were slightly more accurate than the p450 primers. The LAMP assay accurately detected pathogenic R. fascians in 26 of 28 (93%) naturally infected plants and did not react with 23 asymptomatic plants. The LAMP primers also amplified product for DNA extracts of 40 of 41 bacterial strains isolated from plants with leafy galls. The detection limit of both the PCR and LAMP assays was approximately 103 CFU/30-μl reaction. These new tools allow fast, reliable, and accurate detection of R. fascians in vitro and in planta. The LAMP assay in particular is a significant advancement in rapid R. fascians diagnostics, and enables those with limited laboratory facilities to confirm the presence of this pathogen in infected plants.
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Affiliation(s)
- M Serdani
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - M Curtis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - M L Miller
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - J Kraus
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - M L Putnam
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
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Jiang CJ, Shimono M, Sugano S, Kojima M, Liu X, Inoue H, Sakakibara H, Takatsuji H. Cytokinins act synergistically with salicylic acid to activate defense gene expression in rice. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:287-96. [PMID: 23234404 DOI: 10.1094/mpmi-06-12-0152-r] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Hormone crosstalk is pivotal in plant-pathogen interactions. Here, we report on the accumulation of cytokinins (CK) in rice seedlings after infection of blast fungus Magnaporthe oryzae and its potential significance in rice-M. oryzae interaction. Blast infection to rice seedlings increased levels of N(6)-(Δ(2)-isopentenyl) adenine (iP), iP riboside (iPR), and iPR 5'-phosphates (iPRP) in leaf blades. Consistent with this, CK signaling was activated around the infection sites, as shown by histochemical staining for β-glucuronidase activity driven by a CK-responsive OsRR6 promoter. Diverse CK species were also detected in the hyphae (mycelium), conidia, and culture filtrates of blast fungus, indicating that M. oryzae is capable of production as well as hyphal secretion of CK. Co-treatment of leaf blades with CK and salicylic acid (SA), but not with either one alone, markedly induced pathogenesis-related genes OsPR1b and probenazole-induced protein 1 (PBZ1). These effects were diminished by RNAi-knockdown of OsNPR1 or WRKY45, the key regulators of the SA signaling pathway in rice, indicating that the effects of CK depend on these two regulators. Taken together, our data imply a coevolutionary rice-M. oryzae interaction, wherein M. oryzae probably elevates rice CK levels for its own benefits such as nutrient translocation. Rice plants, on the other hand, sense it as an infection signal and activate defense reactions through the synergistic action with SA.
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Affiliation(s)
- Chang-Jie Jiang
- National Institute of Agrobiological Sciences, Tsukuba, Japan.
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Rasamiravaka T, Jedrzejowski A, Kiendrebeogo M, Rajaonson S, Randriamampionona D, Rabemanantsoa C, Andriantsimahavandy A, Rasamindrakotroka A, Duez P, El Jaziri M, Vandeputte OM. Endemic malagasy Dalbergia species inhibit quorum sensing in Pseudomonas aeruginosa PAO1. MICROBIOLOGY-SGM 2013; 159:924-938. [PMID: 23449917 DOI: 10.1099/mic.0.064378-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Various species of the plant genus Dalbergia are traditionally used as medicine for sundry ailments and some of them have been shown recently to quench the virulence of Gram-positive and Gram-negative bacteria. Cell-to-cell communication mechanisms, quorum sensing (QS) in particular, are key regulators of virulence in many pathogenic bacteria. Screening n-hexane extracts of leaves, roots and bark of endemic Malagasy Dalbergia species for their capacity to antagonize QS mechanisms in Pseudomonas aeruginosa PAO1 showed that many reduced the expression of the QS-regulated genes lasB and rhlA. However, only the extract of Dalbergia trichocarpa bark (DTB) showed a significant reduction of QS gene expression without any effect on the aceA gene encoding a QS-independent isocitrate lyase. Further characterization of DTB impact on QS revealed that the QS systems las and rhl are inhibited and that swarming, twitching, biofilm formation and the production of pyocyanin, elastase and proteases are also hampered in the presence of the DTB extract. Importantly, compared with the known QS inhibitor naringenin, the DTB extract showed a stronger negative effect on twitching, biofilm formation and tobramycin resistance. Preliminary structural characterization of these potent biofilm disrupters suggests that they belong to the phytosterols. The strong inhibition of motility and biofilm formation suggests that the DTB extract contains agents disrupting biofilm architecture, which is an important observation in the context of the design of new drugs targeting biofilm-encapsulated pathogens.
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Affiliation(s)
- Tsiry Rasamiravaka
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Anaïs Jedrzejowski
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Martin Kiendrebeogo
- Laboratoire de Biochimie et de Chimie Appliquées, Université de Ouagadougou, 09 BP 848 Ouagadougou 09, Burkina Faso.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Sanda Rajaonson
- Laboratoire de Physiologie Végétale, Université d'Antananarivo, B.P. 906 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Denis Randriamampionona
- Laboratoire de Physiologie Végétale, Université d'Antananarivo, B.P. 906 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Christian Rabemanantsoa
- Laboratoire de Biodiversité et de Biotechnologie, Institut Malgache de Recherches Appliquées (IMRA), B.P. 3833 Avarabohitra Itaosy, Antananarivo 102, Madagascar
| | - Abel Andriantsimahavandy
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar
| | - Andry Rasamindrakotroka
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar
| | - Pierre Duez
- Laboratoire de Pharmacognosie, de Bromatologie et de Nutrition Humaine, Université Libre de Bruxelles, CP 205/9, Boulevard du Triomphe, B-1050 Brussels, Belgium
| | - Mondher El Jaziri
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Olivier M Vandeputte
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
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45
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Chalupowicz L, Weinthal D, Gaba V, Sessa G, Barash I, Manulis-Sasson S. Polar auxin transport is essential for gall formation by Pantoea agglomerans on Gypsophila. MOLECULAR PLANT PATHOLOGY 2013; 14:185-90. [PMID: 23083316 PMCID: PMC6638636 DOI: 10.1111/j.1364-3703.2012.00839.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The virulence of the bacterium Pantoea agglomerans pv. gypsophilae (Pag) on Gypsophila paniculata depends on a type III secretion system (T3SS) and its effectors. The hypothesis that plant-derived indole-3-acetic acid (IAA) plays a major role in gall formation was examined by disrupting basipetal polar auxin transport with the specific inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-naphthylphthalamic acid (NPA). On inoculation with Pag, galls developed in gypsophila stems above but not below lanolin rings containing TIBA or NPA, whereas, in controls, galls developed above and below the rings. In contrast, TIBA and NPA could not inhibit tumour formation in tomato caused by Agrobacterium tumefaciens. The colonization of gypsophila stems by Pag was reduced below, but not above, the lanolin-TIBA ring. Following Pag inoculation and TIBA treatment, the expression of hrpL (a T3SS regulator) and pagR (a quorum-sensing transcriptional regulator) decreased four-fold and that of pthG (a T3SS effector) two-fold after 24 h. Expression of PIN2 (a putative auxin efflux carrier) increased 35-fold, 24 h after Pag inoculation. However, inoculation with a mutant in the T3SS effector pthG reduced the expression of PIN2 by two-fold compared with wild-type infection. The results suggest that pthG might govern the elevation of PIN2 expression during infection, and that polar auxin transport-derived IAA is essential for gall initiation.
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Affiliation(s)
- Laura Chalupowicz
- Department of Plant Pathology and Weed Research, ARO, Volcani Center, Bet Dagan 50250, Israel
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Francis I, De Keyser A, De Backer P, Simón-Mateo C, Kalkus J, Pertry I, Ardiles-Diaz W, De Rycke R, Vandeputte OM, El Jaziri M, Holsters M, Vereecke D. pFiD188, the linear virulence plasmid of Rhodococcus fascians D188. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:637-47. [PMID: 22482837 DOI: 10.1094/mpmi-08-11-0215] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Rhodococcus fascians is currently the only phytopathogen of which the virulence genes occur on a linear plasmid. To get insight into the origin of this replicon and into the virulence strategy of this broad-spectrum phytopathogen, the sequence of the linear plasmid of strain D188, pFiD188, was determined. Analysis of the 198,917 bp revealed four syntenic regions with linear plasmids of R. erythropolis, R. jostii, and R. opacus, suggesting a common origin of these replicons. Mutational analysis of pFi_086 and pFi_102, similar to cutinases and type IV peptidases, respectively, showed that conserved region R2 was involved in plasmid dispersal and pointed toward a novel function for actinobacterial cutinases in conjugation. Additionally, pFiD188 had three regions that were unique for R. fascians. Functional analysis of the stk and nrp loci of regions U2 and U3, respectively, indicated that their role in symptom development was limited compared with that of the previously identified fas, att, and hyp virulence loci situated in region U1. Thus, pFiD188 is a typical rhodococcal linear plasmid with a composite structure that encodes core functions involved in plasmid maintenance and accessory functions, some possibly acquired through horizontal gene transfer, implicated in virulence and the interaction with the host.
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Affiliation(s)
- Isolde Francis
- Department of Plant Biotechnology and Bioinformatics, VIB, 9052 Gent, Belgium
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Stes E, Prinsen E, Holsters M, Vereecke D. Plant-derived auxin plays an accessory role in symptom development upon Rhodococcus fascians infection. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:513-527. [PMID: 22181713 DOI: 10.1111/j.1365-313x.2011.04890.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The biotrophic phytopathogen Rhodococcus fascians has a profound impact on plant development, mainly through its principal virulence factors, a mix of synergistically acting cytokinins that induce shoot formation. Expression profiling of marker genes for several auxin biosynthesis routes and mutant analysis demonstrated that the bacterial cytokinins stimulate the auxin biosynthesis of plants via specific targeting of the indole-3-pyruvic acid (IPA) pathway, resulting in enhanced auxin signaling in infected tissues. The double mutant tryptophan aminotransferase 1-1 tryptophan aminotransferase related 2-1 (taa1-1 tar2-1) of Arabidopsis (Arabidopsis thaliana), in which the IPA pathway is defective, displayed a decreased responsiveness towards R. fascians infection, although bacterial colonization and virulence gene expression were not impaired. These observations implied that plant-derived auxin was employed to reinforce symptom formation. Furthermore, the increased auxin production and, possibly, the accumulating bacterial cytokinins in infected plants modified the polar auxin transport so that new auxin maxima were repetitively established and distributed, a process that is imperative for symptom onset and maintenance. Based on these findings, we extend our model of the mode of action of bacterial and plant signals during the interaction between R. fascians and Arabidopsis.
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Affiliation(s)
- Elisabeth Stes
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
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Abstract
Despite long-standing observations on diverse cytokinin actions, the discovery path to cytokinin signaling mechanisms was tortuous. Unyielding to conventional genetic screens, experimental innovations were paramount in unraveling the core cytokinin signaling circuitry, which employs a large repertoire of genes with overlapping and specific functions. The canonical two-component transcription circuitry involves His kinases that perceive cytokinin and initiate signaling, as well as His-to-Asp phosphorelay proteins that transfer phosphoryl groups to response regulators, transcriptional activators, or repressors. Recent advances have revealed the complex physiological functions of cytokinins, including interactions with auxin and other signal transduction pathways. This review begins by outlining the historical path to cytokinin discovery and then elucidates the diverse cytokinin functions and key signaling components. Highlights focus on the integration of cytokinin signaling components into regulatory networks in specific contexts, ranging from molecular, cellular, and developmental regulations in the embryo, root apical meristem, shoot apical meristem, stem and root vasculature, and nodule organogenesis to organismal responses underlying immunity, stress tolerance, and senescence.
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Affiliation(s)
- Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea.
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