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Unay J, Perret X. A Minimal Genetic Passkey to Unlock Many Legume Doors to Root Nodulation by Rhizobia. Genes (Basel) 2020; 11:genes11050521. [PMID: 32392829 PMCID: PMC7290934 DOI: 10.3390/genes11050521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/31/2022] Open
Abstract
In legume crops, formation of developmentally mature nodules is a prerequisite for efficient nitrogen fixation by populations of rhizobial bacteroids established inside nodule cells. Development of root nodules, and concomitant microbial colonization of plant cells, are constrained by sets of recognition signals exchanged by infecting rhizobia and their legume hosts, with much of the specificity of symbiotic interactions being determined by the flavonoid cocktails released by legume roots and the strain-specific nodulation factors (NFs) secreted by rhizobia. Hence, much of Sinorhizobium fredii strain NGR234 symbiotic promiscuity was thought to stem from a family of >80 structurally diverse NFs and associated nodulation keys in the form of secreted effector proteins and rhamnose-rich surface polysaccharides. Here, we show instead that a mini-symbiotic plasmid (pMiniSym2) carrying only the nodABCIJ, nodS and nodD1 genes of NGR234 conferred promiscuous nodulation to ANU265, a derivative strain cured of the large symbiotic plasmid pNGR234a. The ANU265::pMiniSym2 transconjugant triggered nodulation responses on 12 of the 22 legumes we tested. On roots of Macroptilium atropurpureum, Leucaena leucocephala and Vigna unguiculata, ANU265::pMiniSym2 formed mature-like nodule and successfully infected nodule cells. While cowpea and siratro responded to nodule colonization with defense responses that eventually eliminated bacteria, L. leucocephala formed leghemoglobin-containing mature-like nodules inside which the pMiniSym2 transconjugant established persistent intracellular colonies. These data show seven nodulation genes of NGR234 suffice to trigger nodule formation on roots of many hosts and to establish chronic infections in Leucaena cells.
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Fossou RK, Pothier JF, Zézé A, Perret X. Bradyrhizobium ivorense sp. nov. as a potential local bioinoculant for Cajanus cajan cultures in Côte d'Ivoire. Int J Syst Evol Microbiol 2020; 70:1421-1430. [PMID: 32122457 PMCID: PMC7397250 DOI: 10.1099/ijsem.0.003931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For many smallholder farmers of Sub-Saharan Africa, pigeonpea (Cajanus cajan) is an important crop to make ends meet. To ascertain the taxonomic status of pigeonpea isolates of Côte d’Ivoire previously identified as bradyrhizobia, a polyphasic approach was applied to strains CI-1BT, CI-14A, CI-19D and CI-41S. Phylogeny of 16S ribosomal RNA (rRNA) genes placed these nodule isolates in a separate lineage from current species of the B. elkanii super clade. In phylogenetic analyses of single and concatenated partial dnaK, glnII, gyrB, recA and rpoB sequences, the C. cajan isolates again formed a separate lineage, with strain CI-1BT sharing the highest sequence similarity (95.2 %) with B. tropiciagri SEMIA 6148T. Comparative genomic analyses corroborated the novel species status, with 86 % ANIb and 89 % ANIm as the highest average nucleotide identity (ANI) values with B. elkanii USDA 76T. Although CI-1BT, CI-14A, CI-19D and CI-41S shared similar phenotypic and metabolic properties, growth of CI-41S was slower in/on various media. Symbiotic efficacy varied significantly between isolates, with CI-1BT and CI-41S scoring on the C. cajan ‘Light-Brown’ landrace as the most and least proficient bacteria, respectively. Also proficient on Vigna radiata (mung bean), Vigna unguiculata (cowpea, niébé) and additional C. cajan cultivars, CI-1BT represents a potential bioinoculant adapted to local soil conditions and capable of fostering the growth of diverse legume crops in Côte d'Ivoire. Given the data presented here, we propose the 19 C. cajan isolates to belong to a novel species called Bradyrhizobium ivorense sp. nov., with CI-1BT (=CCOS 1862T=CCMM B1296T) as a type strain.
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Affiliation(s)
- Romain K Fossou
- Laboratoire de Biotechnologies Végétale et Microbienne, Unité Mixte de Recherche et d'Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro, Côte d'Ivoire.,Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Sciences III, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Joël F Pothier
- Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland
| | - Adolphe Zézé
- Laboratoire de Biotechnologies Végétale et Microbienne, Unité Mixte de Recherche et d'Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro, Côte d'Ivoire
| | - Xavier Perret
- Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Sciences III, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Cherni AE, Perret X. Deletion of rRNA Operons of Sinorhizobium fredii Strain NGR234 and Impact on Symbiosis With Legumes. Front Microbiol 2019; 10:154. [PMID: 30814981 PMCID: PMC6381291 DOI: 10.3389/fmicb.2019.00154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/22/2019] [Indexed: 01/08/2023] Open
Abstract
During their lifecycle, from free-living soil bacteria to endosymbiotic nitrogen-fixing bacteroids of legumes, rhizobia must colonize, and cope with environments where nutrient concentrations and compositions vary greatly. Bacterial colonization of legume rhizospheres and of root surfaces is subject to a fierce competition for plant exudates. By contrast root nodules offer to rhizobia sheltered nutrient-rich environments within which the cells that successfully propagated via infection threads can rapidly multiply. To explore the effects on symbiosis of a slower rhizobia growth and metabolism, we deleted one or two copies of the three functional rRNA operons of the promiscuous Sinorhizobium fredii strain NGR234 and examined the impact of these mutations on free-living and symbiotic lifestyles. Strains with two functional rRNA operons (NGRΔrRNA1 and NGRΔrRNA3) grew almost as rapidly as NGR234, and NGRΔrRNA1 was as proficient as the parent strain on all of the five legume species tested. By contrast, the NGRΔrRNA1,3 double mutant, which carried a single rRNA operon and grew significantly slower than NGR234, had a reduced symbiotic proficiency on Cajanus cajan, Macroptilium atropurpureum, Tephrosia vogelii, and Vigna unguiculata. In addition, while NGRΔrRNA1 and NGR234 equally competed for nodulation of V. unguiculata, strain NGRΔrRNA1,3 was clearly outcompeted by wild-type. Surprisingly, on Leucaena leucocephala, NGRΔrRNA1,3 was the most proficient strain and competed equally NGR234 for nodule occupation. Together, these results indicate that for strains with otherwise identical repertoires of symbiotic genes, a faster growth on roots and/or inside plant tissues may contribute to secure access to nodules of some hosts. By contrast, other legumes such as L. leucocephala appear as less selective and capable of providing symbiotic environments susceptible to accommodate strains with a broader spectrum of competences.
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Affiliation(s)
- Ala Eddine Cherni
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Xavier Perret
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
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Saad MM, Michalet S, Fossou R, Putnik-Delić M, Crèvecoeur M, Meyer J, de Malézieux C, Hopfgartner G, Maksimović I, Perret X. Loss of NifQ Leads to Accumulation of Porphyrins and Altered Metal-Homeostasis in Nitrogen-Fixing Symbioses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:208-216. [PMID: 30070615 DOI: 10.1094/mpmi-07-18-0188-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Symbiotic nitrogen fixation between legumes and rhizobia involves a coordinated expression of many plant and bacterial genes as well as finely tuned metabolic activities of micro- and macrosymbionts. In spite of such complex interactions, symbiotic proficiency remains a resilient process, with host plants apparently capable of compensating for some deficiencies in rhizobia. What controls nodule homeostasis is still poorly understood and probably varies between plant species. In this respect, the promiscuous Sinorhizobium (Ensifer) fredii strain NGR234 has become a model to assess the relative contribution of single gene products to many symbioses. Here, we describe how a deletion in nifQ of NGR234 (strain NGRΔnifQ) makes nodules of Vigna unguiculata, V. radiata, and Macroptilium atropurpureum but not of the mimisoid tree Leucaena leucocephala, purple-red. This peculiar dark-nodule phenotype did not necessarily correlate with a decreased proficiency of NGRΔnifQ but coincided with a 20-fold or more accumulation of coproporphyrin III and uroporphyrin III in V. unguiculata nodules. Porphyrin accumulation was not restricted to plant cells infected with bacteroids but also extended to the nodule cortex. Nodule metal-homeostasis was altered but not sufficiently to prevent assembly and functioning of nitrogenase. Although the role of NifQ in donating molybdenum during assembly of nitrogenase cofactor FeMo-co makes it essential in free-living diazotrophs, our results highlight the dispensability of NifQ in many legume species.
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Affiliation(s)
- Maged M Saad
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
- 2 King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal 6900-2355, Kingdom of Saudi Arabia
| | - Sophie Michalet
- 3 University of Geneva, Mass Spectrometry Core Facility (MZ 2.0), Faculty of Sciences, Bd d'Yvoy 11, CH-1211 Geneva 4, Switzerland
| | - Romain Fossou
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | | | - Michèle Crèvecoeur
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Julien Meyer
- 3 University of Geneva, Mass Spectrometry Core Facility (MZ 2.0), Faculty of Sciences, Bd d'Yvoy 11, CH-1211 Geneva 4, Switzerland
| | - Chloé de Malézieux
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Gérard Hopfgartner
- 5 University of Geneva, Department of Inorganic and Analytical Chemistry, Faculty of Sciences, 26 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Ivana Maksimović
- 4 University of Novi Sad, Faculty of Agriculture, Novi Sad, Serbia; and
| | - Xavier Perret
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Temprano-Vera F, Rodríguez-Navarro DN, Acosta-Jurado S, Perret X, Fossou RK, Navarro-Gómez P, Zhen T, Yu D, An Q, Buendía-Clavería AM, Moreno J, López-Baena FJ, Ruiz-Sainz JE, Vinardell JM. Sinorhizobium fredii Strains HH103 and NGR234 Form Nitrogen Fixing Nodules With Diverse Wild Soybeans ( Glycine soja) From Central China but Are Ineffective on Northern China Accessions. Front Microbiol 2018; 9:2843. [PMID: 30519234 PMCID: PMC6258812 DOI: 10.3389/fmicb.2018.02843] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/05/2018] [Indexed: 11/18/2022] Open
Abstract
Sinorhizobium fredii indigenous populations are prevalent in provinces of Central China whereas Bradyrhizobium species (Bradyrhizobium japonicum, B. diazoefficiens, B. elkanii, and others) are more abundant in northern and southern provinces. The symbiotic properties of different soybean rhizobia have been investigated with 40 different wild soybean (Glycine soja) accessions from China, Japan, Russia, and South Korea. Bradyrhizobial strains nodulated all the wild soybeans tested, albeit efficiency of nitrogen fixation varied considerably among accessions. The symbiotic capacity of S. fredii HH103 with wild soybeans from Central China was clearly better than with the accessions found elsewhere. S. fredii NGR234, the rhizobial strain showing the broadest host range ever described, also formed nitrogen-fixing nodules with different G. soja accessions from Central China. To our knowledge, this is the first report describing an effective symbiosis between S. fredii NGR234 and G. soja. Mobilization of the S. fredii HH103 symbiotic plasmid to a NGR234 pSym-cured derivative (strain NGR234C) yielded transconjugants that formed ineffective nodules with G. max cv. Williams 82 and G. soja accession CH4. By contrast, transfer of the symbiotic plasmid pNGR234a to a pSym-cured derivative of S. fredii USDA193 generated transconjugants that effectively nodulated G. soja accession CH4 but failed to nodulate with G. max cv. Williams 82. These results indicate that intra-specific transference of the S. fredii symbiotic plasmids generates new strains with unpredictable symbiotic properties, probably due to the occurrence of new combinations of symbiotic signals.
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Affiliation(s)
| | | | - Sebastian Acosta-Jurado
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
| | - Xavier Perret
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Romain K Fossou
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Pilar Navarro-Gómez
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
| | - Tao Zhen
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin, China
| | - Deshui Yu
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin, China
| | - Qi An
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin, China
| | - Ana Maria Buendía-Clavería
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
| | - Javier Moreno
- Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Francisco Javier López-Baena
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
| | - Jose Enrique Ruiz-Sainz
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
| | - Jose Maria Vinardell
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes, Seville, Spain
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The Rhizobium leucaenae CFN 299 pSym plasmid contains genes expressed in free life and symbiosis, as well as two replication systems. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-017-1257-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Fossou RK, Ziegler D, Zézé A, Barja F, Perret X. Two Major Clades of Bradyrhizobia Dominate Symbiotic Interactions with Pigeonpea in Fields of Côte d'Ivoire. Front Microbiol 2016; 7:1793. [PMID: 27891120 PMCID: PMC5104742 DOI: 10.3389/fmicb.2016.01793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/25/2016] [Indexed: 12/03/2022] Open
Abstract
In smallholder farms of Côte d'Ivoire, particularly in the northeast of the country, Cajanus cajan (pigeonpea) has become an important crop because of its multiple beneficial facets. Pigeonpea seeds provide food to make ends meet, are sold on local markets, and aerial parts serve as forage for animals. Since it fixes atmospheric nitrogen in symbiosis with soil bacteria collectively known as rhizobia, C. cajan also improves soil fertility and reduces fallow time. Yet, seed yields remain low mostly because farmers cannot afford chemical fertilizers. To identify local rhizobial strains susceptible to be used as bio-inoculants to foster pigeonpea growth, root nodules were collected in six fields of three geographically distant regions of Côte d'Ivoire. Nodule bacteria were isolated and characterized using various molecular techniques including matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS) and DNA sequencing. These molecular analyses showed that 63 out of 85 nodule isolates belonged to two major clades of bradyrhizobia, one of which is known as the Bradyrhizobium elkanii super clade. Phylogenies of housekeeping (16S-ITS-23S, rpoB) and symbiotic (nifH) genes were not always congruent suggesting that lateral transfer of nitrogen fixation genes also contributed to define the genome of these bradyrhizobial isolates. Interestingly, no field-, plant-, or cultivar-specific effect was found to shape the profiles of symbiotic strains. In addition, nodule isolates CI-1B, CI-36E, and CI-41A that belong to distinct species, showed similar symbiotic efficiencies suggesting that any of these strains might serve as a proficient inoculant for C. cajan.
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Affiliation(s)
- Romain K Fossou
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva Geneva, Switzerland
| | - Dominik Ziegler
- Microbiology Unit, Department of Botany and Plant Biology, University of GenevaGeneva, Switzerland; Mabritec AGRiehen, Switzerland
| | - Adolphe Zézé
- Laboratoire de Biotechnologies Végétale et Microbienne, Unité Mixte de Recherche et d'Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Félix Houphouët-Boigny (INPHB) Yamoussoukro, Côte d'Ivoire
| | - François Barja
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva Geneva, Switzerland
| | - Xavier Perret
- Microbiology Unit, Department of Botany and Plant Biology, University of Geneva Geneva, Switzerland
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Genome sequencing of two Neorhizobium galegae strains reveals a noeT gene responsible for the unusual acetylation of the nodulation factors. BMC Genomics 2014; 15:500. [PMID: 24948393 PMCID: PMC4085339 DOI: 10.1186/1471-2164-15-500] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/12/2014] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The species Neorhizobium galegae comprises two symbiovars that induce nodules on Galega plants. Strains of both symbiovars, orientalis and officinalis, induce nodules on the same plant species, but fix nitrogen only in their own host species. The mechanism behind this strict host specificity is not yet known. In this study, genome sequences of representatives of the two symbiovars were produced, providing new material for studying properties of N. galegae, with a special interest in genomic differences that may play a role in host specificity. RESULTS The genome sequences confirmed that the two representative strains are much alike at a whole-genome level. Analysis of orthologous genes showed that N. galegae has a higher number of orthologs shared with Rhizobium than with Agrobacterium. The symbiosis plasmid of strain HAMBI 1141 was shown to transfer by conjugation under optimal conditions. In addition, both sequenced strains have an acetyltransferase gene which was shown to modify the Nod factor on the residue adjacent to the non-reducing-terminal residue. The working hypothesis that this gene is of major importance in directing host specificity of N. galegae could not, however, be confirmed. CONCLUSIONS Strains of N. galegae have many genes differentiating them from strains of Agrobacterium, Rhizobium and Sinorhizobium. However, the mechanism behind their ecological difference is not evident. Although the final determinant for the strict host specificity of N. galegae remains to be identified, the gene responsible for the species-specific acetylation of the Nod factors was identified in this study. We propose the name noeT for this gene to reflect its role in symbiosis.
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Sullivan JT, Brown SD, Ronson CW. The NifA-RpoN regulon of Mesorhizobium loti strain R7A and its symbiotic activation by a novel LacI/GalR-family regulator. PLoS One 2013; 8:e53762. [PMID: 23308282 PMCID: PMC3538637 DOI: 10.1371/journal.pone.0053762] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 12/04/2012] [Indexed: 11/19/2022] Open
Abstract
Mesorhizobium loti is the microsymbiont of Lotus species, including the model legume L. japonicus. M. loti differs from other rhizobia in that it contains two copies of the key nitrogen fixation regulatory gene nifA, nifA1 and nifA2, both of which are located on the symbiosis island ICEMlSym(R7A). M. loti R7A also contains two rpoN genes, rpoN1 located on the chromosome outside of ICEMlSym(R7A) and rpoN2 that is located on ICEMlSym(R7A). The aims of the current work were to establish how nifA expression was activated in M. loti and to characterise the NifA-RpoN regulon. The nifA2 and rpoN2 genes were essential for nitrogen fixation whereas nifA1 and rpoN1 were dispensable. Expression of nifA2 was activated, possibly in response to an inositol derivative, by a novel regulator of the LacI/GalR family encoded by the fixV gene located upstream of nifA2. Other than the well-characterized nif/fix genes, most NifA2-regulated genes were not required for nitrogen fixation although they were strongly expressed in nodules. The NifA-regulated nifZ and fixU genes, along with nifQ which was not NifA-regulated, were required in M. loti for a fully effective symbiosis although they are not present in some other rhizobia. The NifA-regulated gene msi158 that encodes a porin was also required for a fully effective symbiosis. Several metabolic genes that lacked NifA-regulated promoters were strongly expressed in nodules in a NifA2-dependent manner but again mutants did not have an overt symbiotic phenotype. In summary, many genes encoded on ICEMlSym(R7A) were strongly expressed in nodules but not free-living rhizobia, but were not essential for symbiotic nitrogen fixation. It seems likely that some of these genes have functional homologues elsewhere in the genome and that bacteroid metabolism may be sufficiently plastic to adapt to loss of certain enzymatic functions.
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Affiliation(s)
- John T. Sullivan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Steven D. Brown
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Clive W. Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- * E-mail:
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The type 3 protein secretion system of Cupriavidus taiwanensis strain LMG19424 compromises symbiosis with Leucaena leucocephala. Appl Environ Microbiol 2012; 78:7476-9. [PMID: 22865066 DOI: 10.1128/aem.01691-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cupriavidus taiwanensis forms proficient symbioses with a few Mimosa species. Inactivation of a type III protein secretion system (T3SS) had no effect on Mimosa pudica but allowed C. taiwanensis to establish chronic infections and fix nitrogen in Leucaena leucocephala. Unlike what was observed for other rhizobia, glutamate rather than plant flavonoids mediated transcriptional activation of this atypical T3SS.
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