1
|
Avontuur JR, Wilken PM, Palmer M, Coetzee MPA, Stępkowski T, Venter SN, Steenkamp ET. Complex evolutionary history of photosynthesis in Bradyrhizobium. Microb Genom 2023; 9:001105. [PMID: 37676703 PMCID: PMC10569730 DOI: 10.1099/mgen.0.001105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/28/2023] [Indexed: 09/08/2023] Open
Abstract
Bradyrhizobium comprises a diverse group of bacteria with various lifestyles. Although best known for their nodule-based nitrogen-fixation in symbiosis with legumes, a select group of bradyrhizobia are also capable of photosynthesis. This ability seems to be rare among rhizobia, and its origin and evolution in these bacteria remain a subject of substantial debate. Therefore, our aim here was to investigate the distribution and evolution of photosynthesis in Bradyrhizobium using comparative genomics and representative genomes from closely related taxa in the families Nitrobacteraceae, Methylobacteriaceae, Boseaceae and Paracoccaceae . We identified photosynthesis gene clusters (PGCs) in 25 genomes belonging to three different Bradyrhizobium lineages, notably the so-called Photosynthetic, B. japonicum and B. elkanii supergroups. Also, two different PGC architectures were observed. One of these, PGC1, was present in genomes from the Photosynthetic supergroup and in three genomes from a species in the B. japonicum supergroup. The second cluster, PGC2, was also present in some strains from the B. japonicum supergroup, as well as in those from the B. elkanii supergroup. PGC2 was largely syntenic to the cluster found in Rhodopseudomonas palustris and Tardiphaga . Bayesian ancestral state reconstruction unambiguously showed that the ancestor of Bradyrhizobium lacked a PGC and that it was acquired horizontally by various lineages. Maximum-likelihood phylogenetic analyses of individual photosynthesis genes also suggested multiple acquisitions through horizontal gene transfer, followed by vertical inheritance and gene losses within the different lineages. Overall, our findings add to the existing body of knowledge on Bradyrhizobium ’s evolution and provide a meaningful basis from which to explore how these PGCs and the photosynthesis itself impact the physiology and ecology of these bacteria.
Collapse
Affiliation(s)
- Juanita R. Avontuur
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - P. Markus Wilken
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Martin P. A. Coetzee
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tomasz Stępkowski
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Warszawa, Poland
| | - Stephanus N. Venter
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Emma T. Steenkamp
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| |
Collapse
|
2
|
Amaral MB, Dos Santos Lopes T, Feder CB, Ribeiro TG, Pacheco RS, Teixeira TN, de Castro Monteiro E, Ramalho IO, de O Macedo R, Boddey RM, Zilli JE, Alves BJR. Bradyrhizobium occurrence in nodules of perennial horsegram. Braz J Microbiol 2022; 53:2065-2075. [PMID: 36074250 PMCID: PMC9679115 DOI: 10.1007/s42770-022-00821-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 08/30/2022] [Indexed: 01/13/2023] Open
Abstract
The introduction of a forage legume into a tropical pasture should decrease the need for N fertilizer, provided biological N2 fixation (BNF) contributes enough to compensate for exported N. Macrotyloma axillare (perennial horsegram) is a suitable legume for composing mixed pastures, and our hypothesis is that the isolation of indigenous rhizobia from roots and rhizosphere is the way of achieving an efficient inoculant to maximize BNF to the legume. Nodules and rhizosphere soil taken from M. axillare grown in a mixed pasture with palisade grass were sampled and used in a trap host assay using Leonard jars containing a mixture of vermiculite and sand. A total of ten bacteria were initially isolated using this technique. The isolates were then used in two experiments to evaluate the inoculation responses on the perennial horsegram in greenhouse conditions to which nodulation, plant growth, and shoot N accumulation were measured. Phylogenetic analyses based on 16S rRNA and recA placed all strains within genus Bradyrhizobium, some of them not previously described. The best strain provided more than 120 nodules and more than 65 mg of nodules per plant. Strain BR14182 was considered the most promising given the high dry matter and N accumulation in plant shoots. This study provides the first analysis of Bradyrhizobium diversity nodulating M. axillare in Brazil and provided evidence of the role of inoculation in incrementing the plant-rhizobium symbiosis in a forage legume.
Collapse
Affiliation(s)
- Mayan Blanc Amaral
- Universidade Federal Rural Do Rio de Janeiro, BR 465, km 07, 23897-000, Seropédica, RJ, Brazil.
| | | | - Caroline Bueno Feder
- Universidade Federal Rural Do Rio de Janeiro, BR 465, km 07, 23897-000, Seropédica, RJ, Brazil
| | | | | | - Thiago Neves Teixeira
- Departamento de Zootecnia, Universidade Federal de Viçosa, Purdue Avenue, 53, 36570-900, Viçosa, MG, Brazil
| | | | - Israel Oliveira Ramalho
- Universidade Federal Rural Do Rio de Janeiro, BR 465, km 07, 23897-000, Seropédica, RJ, Brazil
| | - Robert de O Macedo
- Universidade Federal Rural Do Rio de Janeiro, BR 465, km 07, 23897-000, Seropédica, RJ, Brazil
| | - Robert M Boddey
- Embrapa Agrobiologia, BR 465, km 07, 23891-000, Seropédica, RJ, Brazil
| | - Jerri Edson Zilli
- Embrapa Agrobiologia, BR 465, km 07, 23891-000, Seropédica, RJ, Brazil
| | - Bruno J R Alves
- Embrapa Agrobiologia, BR 465, km 07, 23891-000, Seropédica, RJ, Brazil
| |
Collapse
|
3
|
Ghantasala S, Roy Choudhury S. Nod factor perception: an integrative view of molecular communication during legume symbiosis. PLANT MOLECULAR BIOLOGY 2022; 110:485-509. [PMID: 36040570 DOI: 10.1007/s11103-022-01307-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Compatible interaction between rhizobial Nod factors and host receptors enables initial recognition and signaling events during legume-rhizobia symbiosis. Molecular communication is a new paradigm of information relay, which uses chemical signals or molecules as dialogues for communication and has been witnessed in prokaryotes, plants as well as in animal kingdom. Understanding this fascinating relay of signals between plants and rhizobia during the establishment of a synergistic relationship for biological nitrogen fixation represents one of the hotspots in plant biology research. Predominantly, their interaction is initiated by flavonoids exuding from plant roots, which provokes changes in the expression profile of rhizobial genes. Compatible interactions promote the secretion of Nod factors (NFs) from rhizobia, which are recognised by cognate host receptors. Perception of NFs by host receptors initiates the symbiosis and ultimately leads to the accommodation of rhizobia within root nodules via a series of mutual exchange of signals. This review elucidates the bacterial and plant perspectives during the early stages of symbiosis, explicitly emphasizing the significance of NFs and their cognate NF receptors.
Collapse
Affiliation(s)
- Swathi Ghantasala
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, 517507, India
| | - Swarup Roy Choudhury
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, 517507, India.
| |
Collapse
|
4
|
NoiD, a DedA membrane protein required for homeostasis maintaining of Rhizobium leguminosarum biovar viciae during symbiosis with Pisum sativum. Symbiosis 2022. [DOI: 10.1007/s13199-021-00827-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
5
|
Rai A, Jha MN, Singh D, Thapa S, Chaurasia SK, Jha G. Detection of endophytic association between Aeschynomene nodulating Bradyrhizobium sp. and traditional Desariya rice roots under rice-Aeschynomene ecosystem of chaur land, Bihar, India. Biol Futur 2021; 73:95-105. [PMID: 34773605 DOI: 10.1007/s42977-021-00105-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 11/02/2021] [Indexed: 11/27/2022]
Abstract
Engineering diazotrophic rice having either an integral component of diazotrophic microbes or placing microbial origin nif gene to the rice plant is the dream of biotechnologist. Rice-Aeschynomene ecosystem of pristine chaur land provides a suitable niche to search Rhizobium endophytes in rice. Accordingly, the work was initiated to search suitable endophytic Rhizobium strain for artificial symbiosis within the roots of Desariya rice and its source through morphological, biochemical and molecular approaches. Detection of Acetylene reduction assay (ARA) activity in sterilized Desariya rice root confirmed the presence of putative diazotrophic endophytes in rice root. Isolates from Aeschynomene aspera L. nodulating and Desariya rice endophytic Rhizobium were evaluated for growth, IAA, morphological and biochemical features. Carbon profiling pattern of both these isolates indicated that Desariya rice endophytic Rhizobium has its similarity with Aeschynomene aspera L. nodulating Rhizobium. 16S rRNA gene sequencing confirmed the presence of endophytic Bradyrhizobium sp. in Desariya rice roots and its similarity with Aeschynomene aspera L. nodulating Bradyrhizobium. Desariya rice Bradyrhizobium may be an ideal candidate in the future for creating artificial symbiosis in rice due to its similarity with Aeschynomene aspera L. Bradyrhizobium.
Collapse
Affiliation(s)
- Abhilasha Rai
- Department of Microbiology, College of Basic Sciences and Humanities, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, 848125, India
| | - Manindra Nath Jha
- Department of Microbiology, College of Basic Sciences and Humanities, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, 848125, India
| | - Devendra Singh
- Department of Microbiology, College of Basic Sciences and Humanities, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, 848125, India.
- ICAR-Central Arid Zone Research Institute, Jodhpur, Rajasthan, 342003, India.
| | - Shobit Thapa
- ICAR-National Bureau of Agriculturally Important Microorganisms, Kushmaur, MaunathBhanjan, Uttar Pradesh, 275103, India
| | - Sanjeet Kumar Chaurasia
- Department of Microbiology, College of Basic Sciences and Humanities, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar, 848125, India
| | - Gopaljee Jha
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| |
Collapse
|
6
|
Nouwen N, Chaintreuil C, Fardoux J, Giraud E. A glutamate synthase mutant of Bradyrhizobium sp. strain ORS285 is unable to induce nodules on Nod factor-independent Aeschynomene species. Sci Rep 2021; 11:20910. [PMID: 34686745 PMCID: PMC8536739 DOI: 10.1038/s41598-021-00480-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 11/09/2022] Open
Abstract
The Bradyrhizobium sp. strain ORS285 is able to establish a nitrogen-fixing symbiosis with both Nod factor (NF) dependent and NF-independent Aeschynomene species. Here, we have studied the growth characteristics and symbiotic interaction of a glutamate synthase (GOGAT; gltD::Tn5) mutant of Bradyrhizobium ORS285. We show that the ORS285 gltD::Tn5 mutant is unable to use ammonium, nitrate and many amino acids as nitrogen source for growth and is unable to fix nitrogen under free-living conditions. Moreover, on several nitrogen sources, the growth rate of the gltB::Tn5 mutant was faster and/or the production of the carotenoid spirilloxanthin was much higher as compared to the wild-type strain. The absence of GOGAT activity has a drastic impact on the symbiotic interaction with NF-independent Aeschynomene species. With these species, inoculation with the ORS285 gltD::Tn5 mutant does not result in the formation of nodules. In contrast, the ORS285 gltD::Tn5 mutant is capable to induce nodules on NF-dependent Aeschynomene species, but these nodules were ineffective for nitrogen fixation. Interestingly, in NF-dependent and NF-independent Aeschynomene species inoculation with the ORS285 gltD::Tn5 mutant results in browning of the plant tissue at the site of the infection suggesting that the mutant bacteria induce plant defence responses.
Collapse
Affiliation(s)
- Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France.
| | - Clémence Chaintreuil
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
| | - Joel Fardoux
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
| |
Collapse
|
7
|
Losi A, Gärtner W. A light life together: photosensing in the plant microbiota. Photochem Photobiol Sci 2021; 20:451-473. [PMID: 33721277 DOI: 10.1007/s43630-021-00029-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/17/2021] [Indexed: 12/12/2022]
Abstract
Bacteria and fungi of the plant microbiota can be phytopathogens, parasites or symbionts that establish mutually advantageous relationships with plants. They are often rich in photoreceptors for UVA-Visible light, and in many cases, they exhibit light regulation of growth patterns, infectivity or virulence, reproductive traits, and production of pigments and of metabolites. In addition to the light-driven effects, often demonstrated via the generation of photoreceptor gene knock-outs, microbial photoreceptors can exert effects also in the dark. Interestingly, some fungi switch their attitude towards plants in dependence of illumination or dark conditions in as much as they may be symbiotic or pathogenic. This review summarizes the current knowledge about the roles of light and photoreceptors in plant-associated bacteria and fungi aiming at the identification of common traits and general working ideas. Still, reports on light-driven infection of plants are often restricted to the description of macroscopically observable phenomena, whereas detailed information on the molecular level, e.g., protein-protein interaction during signal transduction or induction mechanisms of infectivity/virulence initiation remains sparse. As it becomes apparent from still only few molecular studies, photoreceptors, often from the red- and the blue light sensitive groups interact and mutually modulate their individual effects. The topic is of great relevance, even in economic terms, referring to plant-pathogen or plant-symbionts interactions, considering the increasing usage of artificial illumination in greenhouses, the possible light-regulation of the synthesis of plant-growth stimulating substances or herbicides by certain symbionts, and the biocontrol of pests by selected fungi and bacteria in a sustainable agriculture.
Collapse
Affiliation(s)
- Aba Losi
- Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/A, 43124, Parma, Italy.
| | - Wolfgang Gärtner
- Institute for Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103, Leipzig, Germany
| |
Collapse
|
8
|
Soares R, Trejo J, Lorite MJ, Figueira E, Sanjuán J, Videira e Castro I. Diversity, Phylogeny and Plant Growth Promotion Traits of Nodule Associated Bacteria Isolated from Lotus parviflorus. Microorganisms 2020; 8:microorganisms8040499. [PMID: 32244524 PMCID: PMC7232477 DOI: 10.3390/microorganisms8040499] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 11/18/2022] Open
Abstract
Lotus spp. are widely used as a forage to improve pastures, and inoculation with elite rhizobial strains is a common practice in many countries. However, only a few Lotus species have been studied in the context of plant-rhizobia interactions. In this study, forty highly diverse bacterial strains were isolated from root nodules of wild Lotus parviflorus plants growing in two field locations in Portugal. However, only 10% of these isolates could nodulate one or more legume hosts tested, whereas 90% were thought to be opportunistic nodule associated bacteria. Phylogenetic studies place the nodulating isolates within the Bradyrhizobium genus, which is closely related to B. canariense and other Bradyrhizobium sp. strains isolated from genistoid legumes and Ornithopus spp. Symbiotic nodC and nifH gene phylogenies were fully consistent with the taxonomic assignment and host range. The non-nodulating bacteria isolated were alpha- (Rhizobium/Agrobacterium), beta- (Massilia) and gamma-proteobacteria (Pseudomonas, Lysobacter, Luteibacter, Stenotrophomonas and Rahnella), as well as some bacteroidetes from genera Sphingobacterium and Mucilaginibacter. Some of these nodule-associated bacteria expressed plant growth promotion (PGP) traits, such as production of lytic enzymes, antagonistic activity against phytopathogens, phosphate solubilization, or siderophore production. This argues for a potential beneficial role of these L. parviflorus nodule-associated bacteria.
Collapse
Affiliation(s)
- Ricardo Soares
- Laboratório de Microbiologia do Solo, UEISSAFSV, Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), 2780-159 Oeiras, Portugal; (R.S.); (J.T.)
- Laboratório de Bioquímica Inorgânica e RMN, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Jesús Trejo
- Laboratório de Microbiologia do Solo, UEISSAFSV, Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), 2780-159 Oeiras, Portugal; (R.S.); (J.T.)
| | - Maria J. Lorite
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, E-18160 Granada, Spain; (M.L.); (J.S.)
| | - Etelvina Figueira
- Departamento de Biologia & CESAM, Universidade de Aveiro, 3810-193 Aveiro, Portugal;
| | - Juan Sanjuán
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, E-18160 Granada, Spain; (M.L.); (J.S.)
| | - Isabel Videira e Castro
- Laboratório de Microbiologia do Solo, UEISSAFSV, Instituto Nacional de Investigação Agrária e Veterinária, I.P. (INIAV, I.P.), 2780-159 Oeiras, Portugal; (R.S.); (J.T.)
- Correspondence:
| |
Collapse
|
9
|
Aeschynomene indica-Nodulating Rhizobia Lacking Nod Factor Synthesis Genes: Diversity and Evolution in Shandong Peninsula, China. Appl Environ Microbiol 2019; 85:AEM.00782-19. [PMID: 31562167 DOI: 10.1128/aem.00782-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 09/04/2019] [Indexed: 02/02/2023] Open
Abstract
Aeschynomene indica is a semiaquatic legume that forms both stem and root nodules with rhizobia. Some A. indica rhizobia (AIRs) have been reported to nodulate the host using a Nod factor-independent pathway and possess photosynthetic abilities. To investigate the diversity and community structure of AIRs in China, a total of 300 rhizobial isolates were acquired from the root and stem nodules of A. indica grown at 4 sites in Shandong Peninsula, China. Nineteen representative strains were selected according to their recA phylogeny. With further classification in comparison with reference strains, 10 Bradyrhizobium genospecies were defined based on the 16S rRNA gene phylogeny and multilocus sequence analysis (MLSA) of housekeeping genes (HKGs) recA, atpD, glnII, dnaK, gyrB, and rpoB In addition, 6 genospecies were found only in China. No nodulation gene (nodA, nodB, nodC, or nodZ) was detected in the AIRs isolates by PCR amplification and Southern blotting. Phylogenetic analysis of nifH and the photosynthesis-related gene pufLM revealed their common origins. All representative strains formed root nodules, but only 9 representative strains for 4 genospecies formed stem nodules on A. indica, indicating that the stem nodulation process of A. indica is limited to some strains. The nucleotide diversity and recombination events of the HKGs, as well as nifH and pufLM genes, showed that mutation contributes more than recombination in evolution. The distribution of dominant AIR genospecies was mainly affected by available nitrogen, organic carbon, total nitrogen, and pH. Our study helps to characterize the diversity and evolution of AIRs.IMPORTANCE Aeschynomene indica rhizobia (AIRs) can form both root and stem nodules via Nod factor-independent processes, which distinguishes them from other rhizobia. This study systematically uncovered the diversity and community composition of A. indica rhizobia distributed in eastern China. Our results reclassified all the A. indica rhizobia across the world and represent a useful contribution to evaluating the diversity and distribution of the symbiont. The presence of novel genospecies specifically distributed in China enriched the A. indica rhizobia resources and provided insight into the geographic distribution of rhizobia. The phylogenetic relationship between nifH and pufLM of A. indica rhizobia across the world provides insight into the evolution of their nitrogen fixation and photosynthetic abilities.
Collapse
|
10
|
Wang J, Hossain MS, Lyu Z, Schmutz J, Stacey G, Xu D, Joshi T. SoyCSN: Soybean context-specific network analysis and prediction based on tissue-specific transcriptome data. PLANT DIRECT 2019; 3:e00167. [PMID: 31549018 PMCID: PMC6747016 DOI: 10.1002/pld3.167] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/12/2019] [Accepted: 08/20/2019] [Indexed: 05/04/2023]
Abstract
The Soybean Gene Atlas project provides a comprehensive map for understanding gene expression patterns in major soybean tissues from flower, root, leaf, nodule, seed, and shoot and stem. The RNA-Seq data generated in the project serve as a valuable resource for discovering tissue-specific transcriptome behavior of soybean genes in different tissues. We developed a computational pipeline for Soybean context-specific network (SoyCSN) inference with a suite of prediction tools to analyze, annotate, retrieve, and visualize soybean context-specific networks at both transcriptome and interactome levels. BicMix and Cross-Conditions Cluster Detection algorithms were applied to detect modules based on co-expression relationships across all the tissues. Soybean context-specific interactomes were predicted by combining soybean tissue gene expression and protein-protein interaction data. Functional analyses of these predicted networks provide insights into soybean tissue specificities. For example, under symbiotic, nitrogen-fixing conditions, the constructed soybean leaf network highlights the connection between the photosynthesis function and rhizobium-legume symbiosis. SoyCSN data and all its results are publicly available via an interactive web service within the Soybean Knowledge Base (SoyKB) at http://soykb.org/SoyCSN. SoyCSN provides a useful web-based access for exploring context specificities systematically in gene regulatory mechanisms and gene relationships for soybean researchers and molecular breeders.
Collapse
Affiliation(s)
- Juexin Wang
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriSt. LouisMOUSA
- Christopher S. Bond Life Sciences CenterUniversity of MissouriSt. LouisMOUSA
| | - Md Shakhawat Hossain
- Christopher S. Bond Life Sciences CenterUniversity of MissouriSt. LouisMOUSA
- Divisions of Plant Science and BiochemistryUniversity of MissouriSt. LouisMOUSA
| | - Zhen Lyu
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriSt. LouisMOUSA
| | - Jeremy Schmutz
- HudsonAlpha Institute for BiotechnologyHuntsvilleALUSA
- DOE Joint Genome InstituteWalnut CreekCAUSA
| | - Gary Stacey
- Christopher S. Bond Life Sciences CenterUniversity of MissouriSt. LouisMOUSA
- Divisions of Plant Science and BiochemistryUniversity of MissouriSt. LouisMOUSA
| | - Dong Xu
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriSt. LouisMOUSA
- Christopher S. Bond Life Sciences CenterUniversity of MissouriSt. LouisMOUSA
- Informatics InstituteUniversity of MissouriSt. LouisMOUSA
| | - Trupti Joshi
- Christopher S. Bond Life Sciences CenterUniversity of MissouriSt. LouisMOUSA
- Informatics InstituteUniversity of MissouriSt. LouisMOUSA
- Department of Health Management and Informatics and Office of ResearchSchool of MedicineUniversity of MissouriSt. LouisMOUSA
| |
Collapse
|
11
|
Avontuur JR, Palmer M, Beukes CW, Chan WY, Coetzee MPA, Blom J, Stępkowski T, Kyrpides NC, Woyke T, Shapiro N, Whitman WB, Venter SN, Steenkamp ET. Genome-informed Bradyrhizobium taxonomy: where to from here? Syst Appl Microbiol 2019; 42:427-439. [PMID: 31031014 DOI: 10.1016/j.syapm.2019.03.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/26/2019] [Accepted: 03/26/2019] [Indexed: 02/06/2023]
Abstract
Bradyrhizobium is thought to be the largest and most diverse rhizobial genus, but this is not reflected in the number of described species. Although it was one of the first rhizobial genera recognised, its taxonomy remains complex. Various contemporary studies are showing that genome sequence information may simplify taxonomic decisions. Therefore, the growing availability of genomes for Bradyrhizobium will likely aid in the delineation and characterization of new species. In this study, we addressed two aims: first, we reviewed the availability and quality of available genomic resources for Bradyrhizobium. This was achieved by comparing genome sequences in terms of sequencing technologies used and estimated level of completeness for inclusion in genome-based phylogenetic analyses. Secondly, we utilized these genomes to investigate the taxonomic standing of Bradyrhizobium in light of its diverse lifestyles. Although genome sequences differed in terms of their quality and completeness, our data indicate that the use of these genome sequences is adequate for taxonomic purposes. By using these resources, we inferred a fully resolved, well-supported phylogeny. It separated Bradyrhizobium into seven lineages, three of which corresponded to the so-called supergroups known for the genus. Wide distribution of key lifestyle traits such as nodulation, nitrogen fixation and photosynthesis revealed that these traits have complicated evolutionary histories. We present the first robust Bradyrhizobium species phylogeny based on genome sequence information for investigating the evolution of this important assemblage of bacteria. Furthermore, this study provides the basis for using genome sequence information as a resource to make important taxonomic decisions, particularly at the species and genus levels.
Collapse
Affiliation(s)
- Juanita R Avontuur
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Chrizelle W Beukes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Wai Y Chan
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa; Biotechnology Platform, Agricultural Research Council Onderstepoort Veterinary Institute (ARC-OVI), Onderstepoort 0110, South Africa
| | - Martin P A Coetzee
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Tomasz Stępkowski
- Autonomous Department of Microbial Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences (SGGW), Poland
| | | | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, United States
| | - Nicole Shapiro
- DOE Joint Genome Institute, Walnut Creek, CA, United States
| | - William B Whitman
- Department of Microbiology, University of Georgia, Athens, GA, United States
| | - Stephanus N Venter
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa. http://emma.steenkamp.up.ac.za
| |
Collapse
|
12
|
Green PN, Ardley JK. Review of the genus Methylobacterium and closely related organisms: a proposal that some Methylobacterium species be reclassified into a new genus, Methylorubrum gen. nov. Int J Syst Evol Microbiol 2018; 68:2727-2748. [PMID: 30024371 DOI: 10.1099/ijsem.0.002856] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genus Methylobacterium, when first proposed by Patt et al. in 1976, was a monospecific genus created to accommodate a single pink pigmented facultatively methylotrophic bacterium. The genus now has over 50 validly published species, however, the percentage 16S rRNA sequence divergence within Methylobacterium questions whether or not they can still be accommodated within one genus. Additionally, several strains are described as belonging to Methylobacterium, but nodulate legumes and in some cases are unable to utilize methanol as a sole carbon source. This study reviews and discusses the current taxonomic status of Methylobacterium. Based on 16S rRNA gene, multi-locus sequence analysis, genomic and phenotypic data, the 52 Methylobacterium species can no longer be retained in one genus. Consequently, a new genus, Methylorubrum gen. nov., is proposed to accommodate 11 species previously held in Methylobacterium. The reclassified species names are proposed as: Methylorubrum aminovorans comb. nov. (type strain TH-15T=NCIMB 13343T=DSM 8832T), Methylorubrum extorquens comb. nov. (type strain NCIMB 9399T=DSM 1337T), Methylorubrum podarium comb. nov. (type strain FM4T=NCIMB 14856T=DSM 15083T), Methylorubrum populi comb. nov. (type strain BJ001T=NCIMB 13946T=ATCC BAA-705T), Methylorubrum pseudosasae comb. nov. (type strain BL44T=ICMP 17622T=NBRC 105205T), Methylorubrum rhodesianum comb. nov. (type strain NCIMB 12249T=DSM 5687T), Methylorubrum rhodinum comb. nov. (type strain NCIMB 9421T=DSM 2163T), Methylorubrum salsuginis comb. nov. (type strain MRT=NCIMB 14847T=NCCB 100140T), Methylorubrum suomiense comb. nov. (type strain F20T=NCIMB 13778T=DSM 14458T), Methylorubrum thiocyanatum comb. nov. (type strain ALL/SCN-PT=NCIMB 13651T=DSM 11490T) and Methylorubrum zatmanii comb. nov. (type strain NCIMB 12243T=DSM 5688T). The taxonomic position of several remaining species is also discussed.
Collapse
Affiliation(s)
- Peter N Green
- 1NCIMB, Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA, UK
| | - Julie K Ardley
- 2School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia
| |
Collapse
|
13
|
Chaintreuil C, Perrier X, Martin G, Fardoux J, Lewis GP, Brottier L, Rivallan R, Gomez-Pacheco M, Bourges M, Lamy L, Thibaud B, Ramanankierana H, Randriambanona H, Vandrot H, Mournet P, Giraud E, Arrighi JF. Naturally occurring variations in the nod-independent model legume Aeschynomene evenia and relatives: a resource for nodulation genetics. BMC PLANT BIOLOGY 2018; 18:54. [PMID: 29614957 PMCID: PMC5883870 DOI: 10.1186/s12870-018-1260-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/06/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Among semi-aquatic species of the legume genus Aeschynomene, some have the unique property of being root and stem-nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the production of Nod factors. These species provide an excellent biological system with which to explore the evolution of nodulation in legumes. Among them, Aeschynomene evenia has emerged as a model legume to undertake the genetic dissection of the so-called Nod-independent symbiosis. In addition to the genetic analysis of nodulation on a reference line, natural variation in a germplasm collection could also be surveyed to uncover genetic determinants of nodulation. To this aim, we investigated the patterns of genetic diversity in a collection of 226 Nod-independent Aeschynomene accessions. RESULTS A combination of phylogenetic analyses, comprising ITS and low-copy nuclear genes, along with cytogenetic experiments and artificial hybridizations revealed the richness of the Nod-independent Aeschynomene group with the identification of 13 diploid and 6 polyploid well-differentiated taxa. A set of 54 SSRs was used to further delineate taxon boundaries and to identify different genotypes. Patterns of microsatellite diversity also illuminated the genetic basis of the Aeschynomene taxa that were all found to be predominantly autogamous and with a predicted simple disomic inheritance, two attributes favorable for genetics. In addition, taxa displaying a pronounced genetic diversity, notably A. evenia, A. indica and A. sensitiva, were characterized by a clear geographically-based genetic structure and variations in root and stem nodulation. CONCLUSION A well-characterized germplasm collection now exists as a major genetic resource to thoroughly explore the natural variation of nodulation in response to different bradyrhizobial strains. Symbiotic polymorphisms are expected to be found notably in the induction of nodulation, in nitrogen fixation and also in stem nodulation. Subsequent genetic analysis and locus mapping will pave the way for the identification of the underlying genes through forward or reverse genetics. Such discoveries will significantly contribute to our understanding of the molecular mechanisms underpinning how some Aeschynomene species can be efficiently nodulated in a Nod-independent fashion.
Collapse
Affiliation(s)
- Clémence Chaintreuil
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Xavier Perrier
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Guillaume Martin
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Joël Fardoux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Gwilym P. Lewis
- Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB UK
| | - Laurent Brottier
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Ronan Rivallan
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Mario Gomez-Pacheco
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud. Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Mickaël Bourges
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud. Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Léo Lamy
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Béatrice Thibaud
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Heriniaina Ramanankierana
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Herizo Randriambanona
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Hervé Vandrot
- IAC, Laboratoire de Botanique et d’Ecologie Végétale Appliquée, UMR AMAP, 98825 Pouembout, Nouvelle-Calédonie, France
| | - Pierre Mournet
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Jean-François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| |
Collapse
|
14
|
Complete Genome Sequence of Bradyrhizobium sp. ORS285, a Photosynthetic Strain Able To Establish Nod Factor-Dependent or Nod Factor-Independent Symbiosis with Aeschynomene Legumes. GENOME ANNOUNCEMENTS 2017; 5:5/30/e00421-17. [PMID: 28751380 PMCID: PMC5532818 DOI: 10.1128/genomea.00421-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here, we report the complete genome sequence of Bradyrhizobium sp. strain ORS285, which is able to nodulate Aeschynomene legumes using two distinct strategies that differ in the requirement of Nod factors. The genome sequence information of this strain will help understanding of the different mechanisms of interaction of rhizobia with legumes.
Collapse
|
15
|
Chaintreuil C, Gully D, Hervouet C, Tittabutr P, Randriambanona H, Brown SC, Lewis GP, Bourge M, Cartieaux F, Boursot M, Ramanankierana H, D'Hont A, Teaumroong N, Giraud E, Arrighi JF. The evolutionary dynamics of ancient and recent polyploidy in the African semiaquatic species of the legume genus Aeschynomene. THE NEW PHYTOLOGIST 2016; 211:1077-1091. [PMID: 27061605 DOI: 10.1111/nph.13956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/04/2016] [Indexed: 06/05/2023]
Abstract
The legume genus Aeschynomene is notable in the ability of certain semiaquatic species to develop nitrogen-fixing stem nodules. These species are distributed in two clades. In the first clade, all the species are characterized by the use of a unique Nod-independent symbiotic process. In the second clade, the species use a Nod-dependent symbiotic process and some of them display a profuse stem nodulation as exemplified in the African Aeschynomene afraspera. To facilitate the molecular analysis of the symbiotic characteristics of such legumes, we took an integrated molecular and cytogenetic approach to track occurrences of polyploidy events and to analyze their impact on the evolution of the African species of Aeschynomene. Our results revealed two rounds of polyploidy: a paleopolyploid event predating the African group and two neopolyploid speciations, along with significant chromosomal variations. Hence, we found that A. afraspera (8x) has inherited the contrasted genomic properties and the stem-nodulation habit of its parental lineages (4x). This study reveals a comprehensive picture of African Aeschynomene diversification. It notably evidences a history that is distinct from the diploid Nod-independent clade, providing clues for the identification of the specific determinants of the Nod-dependent and Nod-independent symbiotic processes, and for comparative analysis of stem nodulation.
Collapse
Affiliation(s)
- Clémence Chaintreuil
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| | - Djamel Gully
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| | - Catherine Hervouet
- CIRAD, UMR AGAP, Plateau de Cytogénétique Moléculaire, 34398, Montpellier, France
| | - Panlada Tittabutr
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Herizo Randriambanona
- Laboratoire de Microbiologie de l'Environnement/Centre National de Recherche sur l'Environnement, Antananarivo, 101, Madagascar
| | - Spencer C Brown
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91 198, Gif-sur-Yvette, France
| | - Gwilym P Lewis
- Comparative Plant and Fungal Biology Department, Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, UK
| | - Mickaël Bourge
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91 198, Gif-sur-Yvette, France
| | - Fabienne Cartieaux
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| | - Marc Boursot
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| | - Heriniaina Ramanankierana
- Laboratoire de Microbiologie de l'Environnement/Centre National de Recherche sur l'Environnement, Antananarivo, 101, Madagascar
| | - Angélique D'Hont
- CIRAD, UMR AGAP, Plateau de Cytogénétique Moléculaire, 34398, Montpellier, France
| | - Neung Teaumroong
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| | - Jean-François Arrighi
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR LSTM, Campus International de Baillarguet, 34398, Montpellier, France
| |
Collapse
|
16
|
Le Roux C, Tournier E, Lies A, Sanguin H, Chevalier G, Duponnois R, Mousain D, Prin Y. Bacteria of the genus Rhodopseudomonas (Bradyrhizobiaceae): obligate symbionts in mycelial cultures of the black truffles Tuber melanosporum and Tuber brumale. SPRINGERPLUS 2016; 5:1085. [PMID: 27468385 PMCID: PMC4947074 DOI: 10.1186/s40064-016-2756-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 07/05/2016] [Indexed: 11/18/2022]
Abstract
BACKGROUND This work aimed at characterizing 12 isolates of the genus Tuber including Tuber melanosporum (11 isolates) and Tuber brumale (one isolate). This was done using internal transcribed spacer (ITS) sequences, confirming their origin. RESULTS Analysis of their mating type revealed that both MAT1-1 and MAT1-2 exist within these isolates (with 3 and 8 of each, respectively). We observed that each of these cultures was consistently associated with one bacterium that was intimately linked to fungal growth. These bacterial associates failed to grow in the absence of fungus. We extracted DNA from bacterial colonies in the margin of mycelium and sequenced a nearly complete 16S rDNA gene and a partial ITS fragment. We found they all belonged to the genus Rhodopseudomonas, fitting within different phylogenetic clusters. No relationships were evidenced between bacterial and fungal strains or mating types. Rhodopseudomonas being a sister genus to Bradyrhizobium, we tested the nodulation ability of these bacteria on a promiscuously nodulating legume (Acacia mangium), without success. We failed to identify any nifH genes among these isolates, using two different sets of primers. CONCLUSIONS While the mechanisms of interaction between Tuber and Rhodopseudomonas remain to be elucidated, their interdependency for in vitro growth seems a novel feature of this fungus.
Collapse
Affiliation(s)
| | | | - Adrien Lies
- />CIRAD, UMR LSTM, 34398 Montpellier Cedex 5, France
| | - Hervé Sanguin
- />CIRAD, UMR LSTM, 34398 Montpellier Cedex 5, France
| | - Gérard Chevalier
- />INRA Centre de Recherche de Clermont-Theix, 63039 Clermont-Ferrand Cedex, France
| | | | - Daniel Mousain
- />Société d’Horticulture et d’Histoire Naturelle de l’Hérault, Parc à Ballon 1, bâtiment B, 125 rue du Moulin de Sémalen, 34000 Montpellier, France
| | - Yves Prin
- />CIRAD, UMR LSTM, 34398 Montpellier Cedex 5, France
| |
Collapse
|
17
|
Nouwen N, Fardoux J, Giraud E. NodD1 and NodD2 Are Not Required for the Symbiotic Interaction of Bradyrhizobium ORS285 with Nod-Factor-Independent Aeschynomene Legumes. PLoS One 2016; 11:e0157888. [PMID: 27315080 PMCID: PMC4912097 DOI: 10.1371/journal.pone.0157888] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/06/2016] [Indexed: 11/23/2022] Open
Abstract
Photosynthetic Bradyrhizobium strain ORS285 forms nitrogen-fixing nodules on the roots and stems of tropical aquatic legumes of the Aeschynomene genus. Depending on the Aeschynomene species, this symbiotic interaction does or does not rely on the synthesis of Nod-factors (NFs). However, whether during the interaction of Bradyrhizobium ORS285 with NF-independent Aeschynomene species the nod genes are expressed and if the general regulator NodD plays a symbiotic role is unknown. Expression studies showed that in contrast to the interaction with the NF-dependent Aeschynomene species, A. afraspera, the Bradyrhizobium ORS285 nod genes are not induced upon contact with the NF-independent host plant A. indica. Mutational analysis of the two nodD genes present in ORS285, showed that deletion of nodD1 and nodD2 did not affect the symbiotic interaction between Bradyrhizobium ORS285 and A. indica whereas the deletions had an effect on the symbiotic interaction with A. afraspera plants. In addition, when the expression of nod genes was artificially induced by adding naringenin to the plant growth medium, the nodulation of A. indica by Bradyrhizobium ORS285 is delayed and resulted in lower nodule numbers.
Collapse
Affiliation(s)
- Nico Nouwen
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/ SupAgro/INRA/ UM2 /CIRAD, Montpellier, France
- * E-mail:
| | - Joel Fardoux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/ SupAgro/INRA/ UM2 /CIRAD, Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/ SupAgro/INRA/ UM2 /CIRAD, Montpellier, France
| |
Collapse
|
18
|
Arrighi JF, Chaintreuil C, Cartieaux F, Cardi C, Rodier-Goud M, Brown SC, Boursot M, D'Hont A, Dreyfus B, Giraud E. Radiation of the Nod-independent Aeschynomene relies on multiple allopolyploid speciation events. THE NEW PHYTOLOGIST 2014; 201:1457-1468. [PMID: 24237245 DOI: 10.1111/nph.12594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 10/08/2013] [Indexed: 06/02/2023]
Abstract
• The semi-aquatic legumes belonging to the genus Aeschynomene constitute a premium system for investigating the origin and evolution of unusual symbiotic features such as stem nodulation and the presence of a Nod-independent infection process. This latter apparently arose in a single Aeschynomene lineage. But how this unique Nod-independent group then radiated is not yet known. • We have investigated the role of polyploidy in Aeschynomene speciation via a case study of the pantropical A. indica and then extended the analysis to the other Nod-independent species. For this, we combined SSR genotyping, genome characterization through flow cytometry, chromosome counting, FISH and GISH experiments, molecular phylogenies using ITS and single nuclear gene sequences, and artificial hybridizations. • These analyses demonstrate the existence of an A. indica polyploid species complex comprising A. evenia (C. Wright) (2n = 2x = 20), A. indica L. s.s. (2n = 4x = 40) and a new hexaploid form (2n = 6x = 60). This latter contains the two genomes present in the tetraploid (A. evenia and A. scabra) and another unidentified genome. Two other species, A. pratensis and A. virginica, are also shown to be of allopolyploid origin. • This work reveals multiple hybridization/polyploidization events, thus highlighting a prominent role of allopolyploidy in the radiation of the Nod-independent Aeschynomene.
Collapse
Affiliation(s)
- Jean-François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| | - Clémence Chaintreuil
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| | - Fabienne Cartieaux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| | - C Cardi
- CIRAD, UMR AGAP, Plateau de Cytogénétique Moléculaire, TA-A 108/03, 34398, Montpellier Cedex 5, France
| | - M Rodier-Goud
- CIRAD, UMR AGAP, Plateau de Cytogénétique Moléculaire, TA-A 108/03, 34398, Montpellier Cedex 5, France
| | - Spencer C Brown
- CNRS, IBiSA Imagerie Gif et Imagif BioCell, Institut des Sciences du Végétal, UPR 2355, Avenue de la Terrasse, 91198, Gif-sur-Yvette, France
| | - Marc Boursot
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| | - Angélique D'Hont
- CIRAD, UMR AGAP, Plateau de Cytogénétique Moléculaire, TA-A 108/03, 34398, Montpellier Cedex 5, France
| | - Bernard Dreyfus
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, 34398, Montpellier Cedex 5, France
| |
Collapse
|
19
|
Chaintreuil C, Arrighi JF, Giraud E, Miché L, Moulin L, Dreyfus B, Munive-Hernández JA, Villegas-Hernandez MDC, Béna G. Evolution of symbiosis in the legume genus Aeschynomene. THE NEW PHYTOLOGIST 2013; 200:1247-59. [PMID: 23879229 DOI: 10.1111/nph.12424] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/24/2013] [Indexed: 05/22/2023]
Abstract
Legumes in the genus Aeschynomene form nitrogen-fixing root nodules in association with Bradyrhizobium strains. Several aquatic and subaquatic species have the additional capacity to form stem nodules, and some of them can symbiotically interact with specific strains that do not produce the common Nod factors synthesized by all other rhizobia. The question of the emergence and evolution of these nodulation characters has been the subject of recent debate. We conducted a molecular phylogenetic analysis of 38 different Aeschynomene species. The phylogeny was reconstructed with both the chloroplast DNA trnL intron and the nuclear ribosomal DNA ITS/5.8S region. We also tested 28 Aeschynomene species for their capacity to form root and stem nodules by inoculating different rhizobial strains, including nodABC-containing strains (ORS285, USDA110) and a nodABC-lacking strain (ORS278). Maximum likelihood analyses resolved four distinct phylogenetic groups of Aeschynomene. We found that stem nodulation may have evolved several times in the genus, and that all Aeschynomene species using a Nod-independent symbiotic process clustered in the same clade. The phylogenetic approach suggested that Nod-independent nodulation has evolved once in this genus, and should be considered as a derived character, and this result is discussed with regard to previous experimental studies.
Collapse
Affiliation(s)
- Clémence Chaintreuil
- IRD/CIRAD/UM2/Supagro, Laboratoire des Symbioses Tropicales et Méditerranéennes, F-34398, Montpellier, France
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Ritchie RJ. The Use of Solar Radiation by the Photosynthetic Bacterium,Rhodopseudomonas palustris: Model Simulation of Conditions Found in a Shallow Pond or a Flatbed Reactor. Photochem Photobiol 2013; 89:1143-62. [DOI: 10.1111/php.12124] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 06/24/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Raymond J. Ritchie
- Tropical Plant Biology Unit; Faculty of Technology and Environment; Prince of Songkla University-Phuket; Kathu; Thailand
| |
Collapse
|
21
|
Arrighi JF, Cartieaux F, Chaintreuil C, Brown S, Boursot M, Giraud E. Genotype delimitation in the Nod-independent model legume Aeschynomene evenia. PLoS One 2013; 8:e63836. [PMID: 23717496 PMCID: PMC3662760 DOI: 10.1371/journal.pone.0063836] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 03/18/2013] [Indexed: 11/28/2022] Open
Abstract
Research on the nitrogen-fixing symbiosis has been so far focused on two model legumes, Medicago truncatula and Lotus japonicus, which use a sophisticated infection process involving infection thread formation. However, in 25% of the legumes, the bacterial entry occurs more simply in an intercellular fashion. Among them, some semi-aquatic Aeschynomene species present the distinctive feature to form nitrogen-fixing nodules on both roots and stems following elicitation by photosynthetic bradyrhizobia that do not produce Nod factors. This interaction is believed to represent a living testimony of the ancestral state of the rhizobium-legume symbiosis. To decipher the molecular mechanisms of this unique Nod-independent nitrogen-fixing symbiosis, we previously identified A. evenia C. Wright as an appropriate model legume, because it displays all the requisites for molecular and genetic approaches. To advance the use of this new model legume species, here we characterized the intraspecific diversity found in A. evenia. For this, the accessions available in germplasm banks were collected and subjected to morphological investigations, genotyping with RAPD and SSR markers, molecular phylogenies using ITS and single nuclear gene sequences, and cross-compatibility tests. These combined analyses revealed an important intraspecific differentiation that led us to propose a new taxonomic classification for A. evenia comprising two subspecies and four varieties. The A. evenia ssp. evenia contains var. evenia and var. pauciciliata whereas A. evenia ssp. serrulata comprises var. serrulata and var. major. This study provides information to exploit efficiently the diversity encountered in A. evenia and proposes subsp. evenia as the most appropriate subspecies for future projects aimed at identifying plant determinants of the Nod-independent symbiotic process.
Collapse
Affiliation(s)
- Jean-François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, Montpellier, France
- * E-mail:
| | - Fabienne Cartieaux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, Montpellier, France
| | - Clémence Chaintreuil
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, Montpellier, France
| | - Spencer Brown
- Centre national de la recherche scientifique, IBiSA Imagerie Gif et Imagif BioCell, Institut des Sciences du Végétal, UPR 2355, Gif-sur-Yvette, France
| | - Marc Boursot
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, Montpellier, France
| |
Collapse
|
22
|
Boeuf D, Cottrell MT, Kirchman DL, Lebaron P, Jeanthon C. Summer community structure of aerobic anoxygenic phototrophic bacteria in the western Arctic Ocean. FEMS Microbiol Ecol 2013; 85:417-32. [PMID: 23560623 DOI: 10.1111/1574-6941.12130] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/02/2013] [Accepted: 04/02/2013] [Indexed: 11/26/2022] Open
Abstract
Aerobic anoxygenic phototrophic (AAP) bacteria are found in a range of aquatic and terrestrial environments, potentially playing unique roles in biogeochemical cycles. Although known to occur in the Arctic Ocean, their ecology and the factors that govern their community structure and distribution in this extreme environment are poorly understood. Here, we examined summer AAP abundance and diversity in the North East Pacific and the Arctic Ocean with emphasis on the southern Beaufort Sea. AAP bacteria comprised up to 10 and 14% of the prokaryotic community in the bottom nepheloid layer and surface waters of the Mackenzie plume, respectively. However, relative AAP abundances were low in offshore waters. Environmental pufM clone libraries revealed that AAP bacteria in the Alphaproteobacteria and Betaproteobacteria classes dominated in offshore and in river-influenced surface waters, respectively. The most frequent AAP group was a new uncultivated betaproteobacterial clade whose abundance decreased along the salinity gradient of the Mackenzie plume even though its photosynthetic genes were actively expressed in offshore waters. Our data indicate that AAP bacterial assemblages represented a mixture of freshwater and marine taxa mostly restricted to the Arctic Ocean and highlight the substantial influence of riverine inputs on their distribution in coastal environments.
Collapse
Affiliation(s)
- Dominique Boeuf
- UPMC, Univ Paris VI, UMR 7144, Adaptation et Diversité en Milieu Marin, Station Biologique, Roscoff, France
| | | | | | | | | |
Collapse
|
23
|
Ritchie RJ, Runcie JW. Photosynthetic Electron Transport in an Anoxygenic Photosynthetic BacteriumAfifella(Rhodopseudomonas)marinaMeasured Using PAM Fluorometry. Photochem Photobiol 2013; 89:370-83. [DOI: 10.1111/j.1751-1097.2012.01241.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 09/07/2012] [Indexed: 12/01/2022]
Affiliation(s)
- Raymond J. Ritchie
- Tropical Environmental Plant Biology Unit; Faculty of Technology and Environment; Prince of Songkla University; Phuket; Thailand
| | | |
Collapse
|
24
|
International Committee on Systematics of Prokaryotes Subcommittee on the taxonomy of Agrobacterium and Rhizobium: minutes of the meeting, 7 September 2010, Geneva, Switzerland. Int J Syst Evol Microbiol 2012; 61:3089-3093. [PMID: 22156799 DOI: 10.1099/ijs.0.036913-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
25
|
Mornico D, Miché L, Béna G, Nouwen N, Verméglio A, Vallenet D, Smith AAT, Giraud E, Médigue C, Moulin L. Comparative genomics of aeschynomene symbionts: insights into the ecological lifestyle of nod-independent photosynthetic bradyrhizobia. Genes (Basel) 2011; 3:35-61. [PMID: 24704842 PMCID: PMC3899966 DOI: 10.3390/genes3010035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/08/2011] [Accepted: 11/23/2011] [Indexed: 11/30/2022] Open
Abstract
Tropical aquatic species of the legume genus Aeschynomene are stem- and root-nodulated by bradyrhizobia strains that exhibit atypical features such as photosynthetic capacities or the use of a nod gene-dependent (ND) or a nod gene-independent (NI) pathway to enter into symbiosis with legumes. In this study we used a comparative genomics approach on nine Aeschynomene symbionts representative of their phylogenetic diversity. We produced draft genomes of bradyrhizobial strains representing different phenotypes: five NI photosynthetic strains (STM3809, ORS375, STM3847, STM4509 and STM4523) in addition to the previously sequenced ORS278 and BTAi1 genomes, one photosynthetic strain ORS285 hosting both ND and NI symbiotic systems, and one NI non-photosynthetic strain (STM3843). Comparative genomics allowed us to infer the core, pan and dispensable genomes of Aeschynomene bradyrhizobia, and to detect specific genes and their location in Genomic Islands (GI). Specific gene sets linked to photosynthetic and NI/ND abilities were identified, and are currently being studied in functional analyses.
Collapse
Affiliation(s)
- Damien Mornico
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| | - Lucie Miché
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| | - Gilles Béna
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| | - Nico Nouwen
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| | - André Verméglio
- Laboratoire de Bioénergétique Cellulaire, CEA Cadarache, DSV, IBEB, 13108 Saint Paul-lez-Durance, France.
| | - David Vallenet
- LABGeM, CEA-Genoscope & CNRS-UMR8030, 91057 Evry, France.
| | | | - Eric Giraud
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| | | | - Lionel Moulin
- IRD-LSTM, UMR113, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
| |
Collapse
|
26
|
Renier A, Maillet F, Fardoux J, Poinsot V, Giraud E, Nouwen N. Photosynthetic Bradyrhizobium Sp. strain ORS285 synthesizes 2-O-methylfucosylated lipochitooligosaccharides for nod gene-dependent interaction with Aeschynomene plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:1440-7. [PMID: 21864045 DOI: 10.1094/mpmi-05-11-0104] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Bradyrhizobium sp. strain ORS285 is a photosynthetic bacterium that forms nitrogen-fixing nodules on the roots and stems of tropical aquatic legumes of the Aeschynomene genus. The symbiotic interaction of Bradyrhizobium sp. strain ORS285 with certain Aeschynomene spp. depends on the presence of nodulation (nod) genes whereas the interaction with other species is nod gene independent. To study the nod gene-dependent molecular dialogue between Bradyrhizobium sp. strain ORS285 and Aeschynomene spp., we used a nodB-lacZ reporter strain to monitor the nod gene expression with various flavonoids. The flavanones liquiritigenin and naringenin were found to be the strongest inducers of nod gene expression. Chemical analysis of the culture supernatant of cells grown in the presence of naringenin showed that the major Nod factor produced by Bradyrhizobium sp. strain ORS285 is a modified chitin pentasaccharide molecule with a terminal N-C(18:1)-glucosamine and with a 2-O-methyl fucose linked to C-6 of the reducing glucosamine. In this respect, the Bradyrhizobium sp. strain ORS285 Nod factor is the same as the major Nod factor produced by the nonphotosynthetic Bradyrhizobium japonicum USDA110 that nodulates the roots of soybean. This suggests a classic nod gene-dependent molecular dialogue between Bradyrhizobium sp. strain ORS285 and certain Aeschynomene spp. This is supported by the fact that B. japonicum USDA110 is able to form N(2)-fixing nodules on both the roots and stems of Aeschynomene afraspera.
Collapse
Affiliation(s)
- Adeline Renier
- Laboratoire des Symbioses Tropicales et Mediterraneennes, UMR IRD, Montpellier, France
| | | | | | | | | | | |
Collapse
|
27
|
Feng Y, Lin X, Yu Y, Zhu J. Elevated ground-level O(3) changes the diversity of anoxygenic purple phototrophic bacteria in paddy field. MICROBIAL ECOLOGY 2011; 62:789-799. [PMID: 21698401 DOI: 10.1007/s00248-011-9895-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 06/10/2011] [Indexed: 05/31/2023]
Abstract
The knowledge of the impact of elevated ground-level O(3) below ground the agro-ecosystem is limited. A field experiment in China Ozone Free-Air Concentration Enrichment (FACE-O(3)) facility on a rice-wheat rotation system was carried out to investigate responses of anoxygenic phototrophic purple bacteria (AnPPB) to elevated ground-level O(3). AnPPB community structures and sizes in paddy soil were monitored by molecular approaches including PCR-DGGE and real-time quantitative PCR based upon the pufM gene on three typical rice growth stages. Repetitive sequence-based PCR (rep-PCR) in combination with culture-reliant method was conducted to reveal changes in genotypic diversity. Elevated ground-level O(3) statistically reduce AnPPB abundance and percentage in total bacterial community in flooded rice soil via decreasing their genotypic diversity and metabolic versatility. Concomitantly, their community composition changed after rice anthesis stage under elevated ground-level O(3). Our results from AnPPB potential responses imply that continuously elevated ground-level O(3) in the future would eventually harm the health of paddy ecosystem through negative effect on soil microorganisms.
Collapse
Affiliation(s)
- Youzhi Feng
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, People's Republic of China
| | | | | | | |
Collapse
|
28
|
Gourion B, Delmotte N, Bonaldi K, Nouwen N, Vorholt JA, Giraud E. Bacterial RuBisCO is required for efficient Bradyrhizobium/Aeschynomene symbiosis. PLoS One 2011; 6:e21900. [PMID: 21750740 PMCID: PMC3130060 DOI: 10.1371/journal.pone.0021900] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/08/2011] [Indexed: 11/18/2022] Open
Abstract
Rhizobia and legume plants establish symbiotic associations resulting in the formation of organs specialized in nitrogen fixation. In such organs, termed nodules, bacteria differentiate into bacteroids which convert atmospheric nitrogen and supply the plant with organic nitrogen. As a counterpart, bacteroids receive carbon substrates from the plant. This rather simple model of metabolite exchange underlies symbiosis but does not describe the complexity of bacteroids' central metabolism. A previous study using the tropical symbiotic model Aeschynomene indica/photosynthetic Bradyrhizobium sp. ORS278 suggested a role of the bacterial Calvin cycle during the symbiotic process. Herein we investigated the role of two RuBisCO gene clusters of Bradyrhizobium sp. ORS278 during symbiosis. Using gene reporter fusion strains, we showed that cbbL1 but not the paralogous cbbL2 is expressed during symbiosis. Congruently, CbbL1 was detected in bacteroids by proteome analysis. The importance of CbbL1 for symbiotic nitrogen fixation was proven by a reverse genetic approach. Interestingly, despite its symbiotic nitrogen fixation defect, the cbbL1 mutant was not affected in nitrogen fixation activity under free living state. This study demonstrates a critical role for bacterial RuBisCO during a rhizobia/legume symbiotic interaction.
Collapse
Affiliation(s)
- Benjamin Gourion
- Laboratoire des Symbioses Tropicales et Méditerranéennes, SupAgro/Institut National de la Recherche Agronomique/Université Montpellier 2/Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France.
| | | | | | | | | | | |
Collapse
|
29
|
Bonaldi K, Gherbi H, Franche C, Bastien G, Fardoux J, Barker D, Giraud E, Cartieaux F. The Nod factor-independent symbiotic signaling pathway: development of Agrobacterium rhizogenes-mediated transformation for the legume Aeschynomene indica. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1537-44. [PMID: 21039272 DOI: 10.1094/mpmi-06-10-0137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The nitrogen-fixing symbiosis between Aeschynomene indica and photosynthetic bradyrhizobia is the only legume-rhizobium association described to date that does not require lipochito-oligosaccharide Nod factors (NF). To assist in deciphering the molecular basis of this NF-independent interaction, we have developed a protocol for Agrobacterium rhizogenes-mediated transformation of A. indica. The cotransformation frequency (79%), the nodulation efficiency of transgenic roots (90%), and the expression pattern of the 35S Cauliflower mosaic virus promoter in transgenic nodules were all comparable to those obtained for model legumes. We have made use of this tool to monitor the heterologous spatio-temporal expression of the pMtENOD11-β-glucuronidase fusion, a widely used molecular reporter for rhizobial infection and nodulation in both legumes and actinorhizal plants. While MtENOD11 promoter activation was not observed in A. indica roots prior to nodulation, strong reporter-gene expression was observed in the invaded cells of young nodules and in the cell layers bordering the central zone of older nodules. We conclude that pMtENOD11 expression can be used as an infection-related marker in A. indica and that Agrobacterium rhizogenes-mediated root transformation of Aeschynomene spp. will be an invaluable tool for determining the molecular basis of the NF-independent symbiosis.
Collapse
Affiliation(s)
- Katia Bonaldi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR IRD/SupAgro/INRA/UM2/CIRAD, F-34398 Montpellier, France
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Bonaldi K, Gourion B, Fardoux J, Hannibal L, Cartieaux F, Boursot M, Vallenet D, Chaintreuil C, Prin Y, Nouwen N, Giraud E. Large-scale transposon mutagenesis of photosynthetic Bradyrhizobium sp. strain ORS278 reveals new genetic loci putatively important for nod-independent symbiosis with Aeschynomene indica. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:760-70. [PMID: 20459315 DOI: 10.1094/mpmi-23-6-0760] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Photosynthetic Bradyrhizobium strains possess the unusual ability to form nitrogen-fixing nodules on a specific group of legumes in the absence of Nod factors. To obtain insight into the bacterial genes involved in this Nod-independent symbiosis, we screened 15,648 Tn5 mutants of Bradyrhizobium sp. strain ORS278 for clones affected in root symbiosis with Aeschynomene indica. From the 268 isolated mutants, 120 mutants were altered in nodule development (Ndv(-)) and 148 mutants were found to be deficient in nitrogen fixation (Fix(-)). More than 50% of the Ndv(-) mutants were found to be altered in purine biosynthesis, strengthening the previous hypothesis of a symbiotic role of a bacterial purine derivative during the Nod-independent symbiosis. The other Ndv(-) mutants were auxotrophic for pyrimidines and amino acids (leucine, glutamate, and lysine) or impaired in genes encoding proteins of unknown function. The Fix(-) mutants were found to be affected in a wide variety of cellular processes, including both novel (n = 56) and previously identified (n = 31) genes important in symbiosis. Among the novel genes identified, several were involved in the Calvin cycle, suggesting that CO(2) fixation could play an important role during this symbiosis.
Collapse
Affiliation(s)
- Katia Bonaldi
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, UMR-IRD/SupAgro/INRA/UM2/CIRAD, F-34398 Montpellier, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Hakoyama T, Niimi K, Watanabe H, Tabata R, Matsubara J, Sato S, Nakamura Y, Tabata S, Jichun L, Matsumoto T, Tatsumi K, Nomura M, Tajima S, Ishizaka M, Yano K, Imaizumi-Anraku H, Kawaguchi M, Kouchi H, Suganuma N. Host plant genome overcomes the lack of a bacterial gene for symbiotic nitrogen fixation. Nature 2010; 462:514-7. [PMID: 19940927 DOI: 10.1038/nature08594] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 10/19/2009] [Indexed: 11/10/2022]
Abstract
Homocitrate is a component of the iron-molybdenum cofactor in nitrogenase, where nitrogen fixation occurs. NifV, which encodes homocitrate synthase (HCS), has been identified from various diazotrophs but is not present in most rhizobial species that perform efficient nitrogen fixation only in symbiotic association with legumes. Here we show that the FEN1 gene of a model legume, Lotus japonicus, overcomes the lack of NifV in rhizobia for symbiotic nitrogen fixation. A Fix(-) (non-fixing) plant mutant, fen1, forms morphologically normal but ineffective nodules. The causal gene, FEN1, was shown to encode HCS by its ability to complement a HCS-defective mutant of Saccharomyces cerevisiae. Homocitrate was present abundantly in wild-type nodules but was absent from ineffective fen1 nodules. Inoculation with Mesorhizobium loti carrying FEN1 or Azotobacter vinelandii NifV rescued the defect in nitrogen-fixing activity of the fen1 nodules. Exogenous supply of homocitrate also recovered the nitrogen-fixing activity of the fen1 nodules through de novo nitrogenase synthesis in the rhizobial bacteroids. These results indicate that homocitrate derived from the host plant cells is essential for the efficient and continuing synthesis of the nitrogenase system in endosymbionts, and thus provide a molecular basis for the complementary and indispensable partnership between legumes and rhizobia in symbiotic nitrogen fixation.
Collapse
Affiliation(s)
- Tsuneo Hakoyama
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Giraud E, Lavergne J, Verméglio A. Characterization of Bacteriophytochromes from Photosynthetic Bacteria. Methods Enzymol 2010; 471:135-59. [DOI: 10.1016/s0076-6879(10)71009-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
33
|
Zhukov VA, Shtark OY, Borisov AY, Tikhonovich IA. Molecular genetic mechanisms used by legumes to control early stages of mutually beneficial (mutualistic) symbiosis. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409110039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
34
|
Miché L, Moulin L, Chaintreuil C, Contreras-Jimenez JL, Munive-Hernández JA, Del Carmen Villegas-Hernandez M, Crozier F, Béna G. Diversity analyses of Aeschynomene symbionts in Tropical Africa and Central America reveal that nod-independent stem nodulation is not restricted to photosynthetic bradyrhizobia. Environ Microbiol 2009; 12:2152-64. [PMID: 21966910 DOI: 10.1111/j.1462-2920.2009.02090.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tropical aquatic legumes of the genus Aeschynomene are unique in that they can be stem-nodulated by photosynthetic bradyrhizobia. Moreover, a recent study demonstrated that two Aeschynomene indica symbionts lack canonical nod genes, thereby raising questions about the distribution of such atypical symbioses among rhizobial-legume interactions. Population structure and genomic diversity were compared among stem-nodulating bradyrhizobia isolated from various Aeschynomene species of Central America and Tropical Africa. Phylogenetic analyses based on the recA gene and whole-genome amplified fragment length polymorphism (AFLP) fingerprints on 110 bacterial strains highlighted that all the photosynthetic strains form a separate cluster among bradyrhizobia, with no obvious structuring according to their geographical or plant origins. Nod-independent symbiosis was present in all sampling areas and seemed to be linked to Aeschynomene host species. However, it was not strictly dependent on photosynthetic ability, as exemplified by a newly identified cluster of strains that lacked canonical nod genes and efficiently stem-nodulated A. indica, but were not photosynthetic. Interestingly, the phenotypic properties of this new cluster of bacteria were reflected by their phylogenetical position, as being intermediate in distance between classical root-nodulatingBradyrhizobium spp. and photosynthetic ones. This result opens new prospects about stem-nodulating bradyrhizobial evolution.
Collapse
|
35
|
Masson-Boivin C, Giraud E, Perret X, Batut J. Establishing nitrogen-fixing symbiosis with legumes: how many rhizobium recipes? Trends Microbiol 2009; 17:458-66. [PMID: 19766492 DOI: 10.1016/j.tim.2009.07.004] [Citation(s) in RCA: 422] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 07/06/2009] [Accepted: 07/13/2009] [Indexed: 11/27/2022]
Abstract
Rhizobia are phylogenetically disparate alpha- and beta-proteobacteria that have achieved the environmentally essential function of fixing atmospheric nitrogen (N(2)) in symbiosis with legumes. All rhizobia elicit the formation of root - or occasionally stem - nodules, plant organs dedicated to the fixation and assimilation of nitrogen. Bacterial colonization of these nodules culminates in a remarkable case of sustained intracellular infection in plants. Rhizobial phylogenetic diversity raised the question of whether these soil bacteria shared a common core of symbiotic genes. In this article, we review the cumulative evidence from recent genomic and genetic analyses pointing toward an unexpected variety of mechanisms that lead to symbiosis with legumes.
Collapse
Affiliation(s)
- Catherine Masson-Boivin
- Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR CNRS-INRA 2594/441, BP 52627, 31326 Castanet Tolosan Cedex, France.
| | | | | | | |
Collapse
|
36
|
Jaubert M, Hannibal L, Fardoux J, Giraud E, Verméglio A. Identification of novel genes putatively involved in the photosystem synthesis of Bradyrhizobium sp. ORS 278. PHOTOSYNTHESIS RESEARCH 2009; 100:97-105. [PMID: 19452262 DOI: 10.1007/s11120-009-9433-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 05/04/2009] [Indexed: 05/27/2023]
Abstract
In aerobic anoxygenic phototrophs, oxygen is required for both the formation of the photosynthetic apparatus and an efficient cyclic electron transfer. Mutants of Bradyrhizobium sp. ORS278 affected in photosystem synthesis were selected by a bacteriochlorophyll fluorescence-based screening. Out of the 9,600 mutants of a random Tn5 insertion library, 50 clones, corresponding to insertions in 28 different genes, present a difference in fluorescence intensity compared to the WT. Besides enzymes and regulators known to be involved in photosystem synthesis, 14 novel components of the photosynthesis control are identified. Among them, two genes, hsIU and hsIV, encode components of a protein degradation complex, probably linked to the renewal of photosystem, an important issue in Bradyrhizobia which have to deal with harmful reactive oxygen species. The presence of homologs in non-photosynthetic bacteria for most of the regulatory genes identified during study suggests that they could be global regulators, as the RegA-RegB system.
Collapse
Affiliation(s)
- Marianne Jaubert
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, AGRO-M, INRA, UM2. TA A-82/J, Campus de Baillarguet, 34398, Montpellier Cedex 5, France
| | | | | | | | | |
Collapse
|
37
|
Abstract
Rhizobia - a diverse group of soil bacteria - induce the formation of nitrogen-fixing nodules on the roots of legumes. Nodulation begins when the roots initiate a molecular dialogue with compatible rhizobia in the soil. Most rhizobia reply by secreting lipochitooligosaccharidic nodulation factors that enable entry into the legume. A molecular exchange continues, which, in compatible interactions, permits rhizobia to invade root cortical cells, differentiate into bacteroids and fix nitrogen. Rhizobia also use additional molecular signals, such as secreted proteins or surface polysaccharides. One group of proteins secreted by rhizobia have homologues in bacterial pathogens and may have been co-opted by rhizobia for symbiotic purposes.
Collapse
|
38
|
|
39
|
Control of peripheral light-harvesting complex synthesis by a bacteriophytochrome in the aerobic photosynthetic bacterium Bradyrhizobium strain BTAi1. J Bacteriol 2008; 190:5824-31. [PMID: 18606738 DOI: 10.1128/jb.00524-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recent sequence analysis of the photosynthetic and plant-symbiotic Bradyrhizobium sp. strain BTAi1 revealed the unexpected presence of a pucBA operon encoding the apoproteins of peripheral light-harvesting (LH) complexes. This pucBA operon is found close to a bacteriophytochrome gene (BphP3(B BTAi1)) and a two-component transcriptional regulator gene (TF(BTAi1) gene). In this study, we show that BphP3(B BTAi1) acts as a bona fide bacteriophytochrome and controls, according to light conditions, the expression of the pucBA operon found in its vicinity. This light regulatory pathway is very similar to the one previously described for chromo-BphP4(Rp) in Rhodopseudomonas palustris and conducts the synthesis of a peripheral LH complex. This LH complex presents a single absorption band at low temperature, centered at 803 nm. Fluorescence emission analysis of intact cells indicates that this peripheral LH complex does not act as an efficient light antenna. One putative function of this LH complex could be to evacuate excess light energy in order to protect Bradyrhizobium strain BTAi1, an aerobic anoxygenic photosynthetic bacterium, against photooxidative damage during photosynthesis.
Collapse
|
40
|
Insights learned from pBTAi1, a 229-kb accessory plasmid from Bradyrhizobium sp. strain BTAi1 and prevalence of accessory plasmids in other Bradyrhizobium sp. strains. ISME JOURNAL 2008; 2:158-70. [DOI: 10.1038/ismej.2007.105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
41
|
Terakado-Tonooka J, Ohwaki Y, Yamakawa H, Tanaka F, Yoneyama T, Fujihara S. Expressed nifH Genes of Endophytic Bacteria Detected in Field-Grown Sweet Potatoes (Ipomoea batatas L.). Microbes Environ 2008; 23:89-93. [DOI: 10.1264/jsme2.23.89] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
42
|
Affiliation(s)
- Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR113, IRD, CIRAD, AGRO-M, INRA, UM2, TA A-82/J, Campus de Baillarguet, 34398 Montpellier Cedex 5, France.
| |
Collapse
|
43
|
Giraud E, Moulin L, Vallenet D, Barbe V, Cytryn E, Avarre JC, Jaubert M, Simon D, Cartieaux F, Prin Y, Bena G, Hannibal L, Fardoux J, Kojadinovic M, Vuillet L, Lajus A, Cruveiller S, Rouy Z, Mangenot S, Segurens B, Dossat C, Franck WL, Chang WS, Saunders E, Bruce D, Richardson P, Normand P, Dreyfus B, Pignol D, Stacey G, Emerich D, Verméglio A, Médigue C, Sadowsky M. Legumes symbioses: absence of Nod genes in photosynthetic bradyrhizobia. Science 2007; 316:1307-12. [PMID: 17540897 DOI: 10.1126/science.1139548] [Citation(s) in RCA: 471] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Leguminous plants (such as peas and soybeans) and rhizobial soil bacteria are symbiotic partners that communicate through molecular signaling pathways, resulting in the formation of nodules on legume roots and occasionally stems that house nitrogen-fixing bacteria. Nodule formation has been assumed to be exclusively initiated by the binding of bacterial, host-specific lipochito-oligosaccharidic Nod factors, encoded by the nodABC genes, to kinase-like receptors of the plant. Here we show by complete genome sequencing of two symbiotic, photosynthetic, Bradyrhizobium strains, BTAi1 and ORS278, that canonical nodABC genes and typical lipochito-oligosaccharidic Nod factors are not required for symbiosis in some legumes. Mutational analyses indicated that these unique rhizobia use an alternative pathway to initiate symbioses, where a purine derivative may play a key role in triggering nodule formation.
Collapse
Affiliation(s)
- Eric Giraud
- Institut de Recherche pour le Développement, Centre de Coopération International en Recherche Agronomique pour le Développement, Institut National de la Recherche Agronomique, Université Montpellier 2, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Jaubert M, Lavergne J, Fardoux J, Hannibal L, Vuillet L, Adriano JM, Bouyer P, Pignol D, Giraud E, Verméglio A. A singular bacteriophytochrome acquired by lateral gene transfer. J Biol Chem 2007; 282:7320-8. [PMID: 17218312 DOI: 10.1074/jbc.m611173200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Bacteriophytochromes are phytochrome-like proteins that mediate photosensory responses in various bacteria according to their light environment. The genome of the photosynthetic and plant-symbiotic Bradyrhizobium sp. strain ORS278 revealed the presence of a genomic island acquired by lateral transfer harboring a bacteriophytochrome gene, BrBphP3.ORS278, and genes involved in the synthesis of phycocyanobilin and gas vesicles. The corresponding protein BrBphP3.ORS278 is phylogenetically distant from the other (bacterio)phytochromes described thus far and displays a series of unusual properties. It binds phycocyanobilin as a chromophore, a unique feature for a bacteriophytochrome. Moreover, its C-terminal region is short and displays no homology with any known functional domain. Its dark-adapted state absorbs maximally around 610 nm, an unusually short wavelength for (bacterio)phytochromes. This form is designated as Po for orange-absorbing form. Upon illumination, a photo-reversible switch occurs between the Po form and a red (670 nm)-absorbing form (Pr), which rapidly backreacts in the dark. Because of this instability, illumination results in a mixture of the Po and Pr states in proportions that depend on the intensity. These uncommon features suggest that BrBphP3.ORS278 could be fitted to measure light intensity rather than color.
Collapse
Affiliation(s)
- Marianne Jaubert
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Campus de Baillarguet, 34398 Montpellier, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Montecchia MS, Pucheu NL, Kerber NL, García AF. Oxygen and light effects on the expression of the photosynthetic apparatus in Bradyrhizobium sp. C7T1 strain. PHOTOSYNTHESIS RESEARCH 2006; 90:215-22. [PMID: 17279441 DOI: 10.1007/s11120-007-9129-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 12/29/2006] [Indexed: 05/13/2023]
Abstract
Photosynthetic bradyrhizobia are nitrogen-fixing symbionts colonizing the stem and roots of some leguminous plants like Aeschynomene. The effect of oxygen and light on the formation of the photosynthetic apparatus of Bradyrhizobium sp. C7T1 strain is described here. Oxygen is required for growth, but at high concentration inhibits the synthesis of bacteriochlorophyll (BChl) and of the photosynthetic apparatus. However, we show that in vitro, aerobic photosynthetic electron transport occurred leading to ADP photophosphorylation. The expression of the photosynthetic apparatus was regulated by oxygen in a manner which did not agree with earlier results in other photosynthetic bradyrhizobia since BChl accumulation was the highest under microaerobic conditions. This strain produces photosynthetic pigments when grown under cyclic illumination or darkness. However, under continuous white light illumination, a Northern blot analysis of the puf operon showed that, the expression of the photosynthetic genes of the antenna was considerable. Under latter conditions BChl accumulation in the cells was dependent on the oxygen concentration. It was not detectable at high oxygen tensions but became accumulated under low oxygen (microaerobiosis). It is known that in photosynthetic bradyrhizobia bacteriophytochrome photoreceptor (BphP) partially controls the synthesis of the photosystem in response to light. In C7T1 strain far-red light illumination did not stimulate the synthesis of the photosynthetic apparatus suggesting the presence of a non-functional BphP-mediated light regulatory mechanism.
Collapse
Affiliation(s)
- M S Montecchia
- Instituto de Investigaciones Bioquímicas y Fisiológicas (IBYF-CONICET) and Cátedra de Microbiología Agrícola, Facultad de Agronomía, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
| | | | | | | |
Collapse
|
46
|
Prell J, Poole P. Metabolic changes of rhizobia in legume nodules. Trends Microbiol 2006; 14:161-8. [PMID: 16520035 DOI: 10.1016/j.tim.2006.02.005] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 02/06/2006] [Accepted: 02/21/2006] [Indexed: 12/01/2022]
Abstract
Bacteria have evolved a wide variety of metabolic strategies to cope with varied environments. Some are specialists and only able to survive in restricted environments; others are generalists and able to cope with diverse environmental conditions. Rhizobia (e.g. Rhizobium, Sinorhizobium, Bradyrhizobium, Mesorhizobium and Azorhizobium species) can survive and compete for nutrients in soil and the plant rhizosphere but can also form a beneficial symbiosis with legumes in a highly specialized plant cell environment. Inside the legume-root nodule, the bacteria (bacteroids) reduce dinitrogen to ammonium, which is secreted to the plant in exchange for a carbon and energy source. A new and challenging aspect of nodule physiology is that nitrogen fixation requires the cycling of amino acids between the bacteroid and plant. This review aims to summarize the metabolic plasticity of rhizobia and the importance of amino acid cycling.
Collapse
Affiliation(s)
- Juergen Prell
- School of Biological Sciences, University of Reading, UK, RG6 6AJ
| | | |
Collapse
|
47
|
Elsen S, Jaubert M, Pignol D, Giraud E. PpsR: a multifaceted regulator of photosynthesis gene expression in purple bacteria. Mol Microbiol 2005; 57:17-26. [PMID: 15948946 DOI: 10.1111/j.1365-2958.2005.04655.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Purple bacteria control the level of expression and the composition of their photosystem according to light and redox conditions. This control involves several regulatory systems that have been now well characterized. Among them, the PpsR regulator plays a central role, because it directly or indirectly controls the synthesis of all of the different components of the photosystem. In this review, we report our knowledge of the PpsR protein, highlighting the diversity of its mode of action and focusing on the proteins identified in four model purple bacteria (Rhodobacter capsulatus, Rhodobacter sphaeroides, Rubrivivax gelatinosus, Bradyrhizobium ORS278). This regulator exhibits unique regulatory features in each bacterium: it can activate and/or repress the expression of photosynthesis genes, its activity can be modulated or not by the redox conditions, it can interact with other specific regulators and therefore be involved differently in light and/or redox regulatory circuits.
Collapse
Affiliation(s)
- Sylvie Elsen
- Laboratoire de Biochimie et Biophysique des Systèmes Intégrés (UMR 5092 CNRS-CEA-UJF), CEA-Grenoble, 38054 Grenoble Cedex 9, France
| | | | | | | |
Collapse
|