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MS of the six isomers of (GlcN)2(GlcNAc)2 aminoglucan tetrasaccharides (diacetylchitotetraoses): Rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides. Carbohydr Polym 2011. [DOI: 10.1016/j.carbpol.2010.04.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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102
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Lee WK, Jeong N, Indrasumunar A, Gresshoff PM, Jeong SC. Glycine max non-nodulation locus rj1: a recombinogenic region encompassing a SNP in a lysine motif receptor-like kinase (GmNFR1α). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 122:875-84. [PMID: 21104396 DOI: 10.1007/s00122-010-1493-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 11/04/2010] [Indexed: 05/30/2023]
Abstract
The rj1 mutation of soybean is a simple recessive allele in a single line that arose as a spontaneous mutation in a population; it exhibits non-nodulation with virtually all Bradyrhizobium and Sinorhizobium strains. Here, we described fine genetic and physical mapping of the rj1 locus on soybean chromosome 2. The initial mapping of the rj1 locus using public markers indicated that A343.p2, a sequence-based marker that contains sequence similar to a part of the LjNFR1 gene regulating nodule formation as a member of lysin motif-type receptor-like kinase (LYK) family, maps very close to or cosegregates with the rj1 locus. The sequence of A343.p2 is 100% identical to parts of two BAC clone sequences (GM_WBb0002O19 and GM_WBb098N11) that contain three members of the LYK family. We analyzed the sequence contig (262 kbp) of the two BAC clones by resequencing and subsequent fine genetic and physical mapping. The results indicated that rj1 is located in a gene-rich region with a recombination rate of 120 kbp/cM: several fold higher than the genome average. Among the LYK genes, NFR1α is most likely the gene encoded at the Rj1 locus. The non-nodulating rj1 allele was created by a single base-pair deletion that results in a premature stop codon. Taken together, the fine genetic and physical mapping of the Rj1-residing chromosomal region, combined with the unexpected observation of a putative recombination hotspot, allowed us to demonstrate that the Rj1 locus most likely encodes the NFR1α gene.
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Affiliation(s)
- Woo Kyu Lee
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongwon, Chungbuk, Republic of Korea
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103
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Combes-Meynet E, Pothier JF, Moënne-Loccoz Y, Prigent-Combaret C. The Pseudomonas secondary metabolite 2,4-diacetylphloroglucinol is a signal inducing rhizoplane expression of Azospirillum genes involved in plant-growth promotion. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:271-84. [PMID: 21043573 DOI: 10.1094/mpmi-07-10-0148] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
During evolution, plants have become associated with guilds of plant-growth-promoting rhizobacteria (PGPR), which raises the possibility that individual PGPR populations may have developed mechanisms to cointeract with one another on plant roots. We hypothesize that this has resulted in signaling phenomena between different types of PGPR colonizing the same roots. Here, the objective was to determine whether the Pseudomonas secondary metabolite 2,4-diacetylphloroglucinol (DAPG) can act as a signal on Azospirillum PGPR and enhance the phytostimulation effects of the latter. On roots, the DAPG-producing Pseudomonas fluorescens F113 strain but not its phl-negative mutant enhanced the phytostimulatory effect of Azospirillum brasilense Sp245-Rif on wheat. Accordingly, DAPG enhanced Sp245-Rif traits involved in root colonization (cell motility, biofilm formation, and poly-β-hydroxybutyrate production) and phytostimulation (auxin production). A differential fluorescence induction promoter-trapping approach based on flow cytometry was then used to identify Sp245-Rif genes upregulated by DAPG. DAPG enhanced expression of a wide range of Sp245-Rif genes, including genes involved in phytostimulation. Four of them (i.e., ppdC, flgE, nirK, and nifX-nifB) tended to be upregulated on roots in the presence of P. fluorescens F113 compared with its phl-negative mutant. Our results indicate that DAPG can act as a signal by which some beneficial pseudomonads may stimulate plant-beneficial activities of Azospirillum PGPR.
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104
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Borjigin N, Furukawa K, Shimoda Y, Tabata S, Sato S, Eda S, Minamisawa K, Mitsui H. Identification of Mesorhizobium loti Genes Relevant to Symbiosis by Using Signature-Tagged Mutants. Microbes Environ 2011; 26:165-71. [DOI: 10.1264/jsme2.me10213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | | | | | | | - Shima Eda
- Graduate School of Life Sciences, Tohoku University
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105
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Altomare C, Tringovska I. Beneficial Soil Microorganisms, an Ecological Alternative for Soil Fertility Management. SUSTAINABLE AGRICULTURE REVIEWS 2011. [DOI: 10.1007/978-94-007-1521-9_6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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106
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Leach J, Keyster M, Du Plessis M, Ludidi N. Nitric oxide synthase activity is required for development of functional nodules in soybean. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:1584-91. [PMID: 20709426 DOI: 10.1016/j.jplph.2010.06.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 06/03/2010] [Accepted: 06/03/2010] [Indexed: 05/08/2023]
Abstract
The effects of a nitric oxide synthase inhibitor (N(ω)-nitro-L-arginine) on soybean growth parameters and nodule functioning were investigated, along with soybean nodule cell viability and cysteine endopeptidase activity. N(ω)-nitro-L-arginine reduced soybean growth parameters, inhibited nodule nitrogenase activity, and caused a decrease in nodule cell viability. The negative effects of N(ω)-nitro-L-arginine were reversed by the nitric oxide donor 2,2'-(hydroxynitrosohydrazono)bis-ethanimine. Cysteine endopeptidase activity was higher in plants treated with N(ω)-nitro-L-arginine than untreated plants (controls), but decreased to levels similar to the controls when plants were exposed to a combination of N(ω)-nitro-L-arginine and 2,2'-(hydroxynitrosohydrazono)bis-ethanimine. These results suggest that nitric oxide, resulting from nitric oxide synthase activity, is required for development of functional soybean nodules.
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Affiliation(s)
- Jacobus Leach
- Institute for Plant Biotechnology, Stellenbosch University, Private Bag X1, Matieland, South Africa
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107
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Novák K. Early action of pea symbiotic gene NOD3 is confirmed by adventitious root phenotype. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2010; 179:472-478. [PMID: 21802605 DOI: 10.1016/j.plantsci.2010.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 07/12/2010] [Accepted: 07/13/2010] [Indexed: 05/31/2023]
Abstract
A supernodulating and Nts (nitrate-tolerant symbiosis) symbiotic mutation of pea (Pisum sativum L.) line RisfixC was found to retain its expression in the distant genetic background of pea lines Afghanistan L1268, Zhodino E900, and cv. Arvika. This finding allowed for reliable scoring for the trait in mapping crosses. The RisfixC mutation was localized 8.2cM apart from SYM2 and cosegregated with molecular markers for SYM2-NOD3 region Psc923 and OA-1. Grafting experiments showed that supernodulation is root-determined, consistently with mutants in the NOD3 locus. Therefore, the mutation of RisfixC can be localized in gene NOD3. Like in other published nod3 alleles, the RisfixC mutation determines supernodulation when it is expressed in the root but not in the shoot. Supernodulated adventitious roots that are spontaneously formed in the wild-type scions on mutant rootstocks indicate that the descending systemic signal, which is inhibitory to nodule formation, is absent in this type of chimeric plants. Since the descending signal production in the wild-type shoot reflects the presence of the ascending root signal, the nod3-associated lesion must be located in the beginning of the systemic circuit regulating nodule number.
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Affiliation(s)
- Karel Novák
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská l083, 142 20 Prague 4, Czech Republic.
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108
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Bou Khalil M, Hou W, Zhou H, Elisma F, Swayne LA, Blanchard AP, Yao Z, Bennett SAL, Figeys D. Lipidomics era: accomplishments and challenges. MASS SPECTROMETRY REVIEWS 2010; 29:877-929. [PMID: 20931646 DOI: 10.1002/mas.20294] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Lipid mediators participate in signal transduction pathways, proliferation, apoptosis, and membrane trafficking in the cell. Lipids are highly complex and diverse owing to the various combinations of polar headgroups, fatty acyl chains, and backbone structures. This structural diversity continues to pose a challenge for lipid analysis. Here we review the current state of the art in lipidomics research and discuss the challenges facing this field. The latest technological developments in mass spectrometry, the role of bioinformatics, and the applications of lipidomics in lipid metabolism and cellular physiology and pathology are also discussed.
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Affiliation(s)
- Maroun Bou Khalil
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada K1H 8M5
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109
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de Lucena DKC, Pühler A, Weidner S. The role of sigma factor RpoH1 in the pH stress response of Sinorhizobium meliloti. BMC Microbiol 2010; 10:265. [PMID: 20955556 PMCID: PMC2976971 DOI: 10.1186/1471-2180-10-265] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 10/18/2010] [Indexed: 11/14/2022] Open
Abstract
Background Environmental pH stress constitutes a limiting factor for S. meliloti survival and development. The response to acidic pH stress in S. meliloti is versatile and characterized by the differential expression of genes associated with various cellular functions. The purpose of this study was to gain detailed insight into the participation of sigma factors in the complex stress response system of S. meliloti 1021 using pH stress as an effector. Results In vitro assessment of S meliloti wild type and sigma factor mutants provided first evidence that the sigma factor RpoH1 plays a major role in the pH stress response. Differential expression of genes related to rhizobactin biosynthesis was observed in microarray analyses performed with the rpoH1 mutant at pH 7.0. The involvement of the sigma factor RpoH1 in the regulation of S. meliloti genes upon pH stress was analyzed by comparing time-course experiments of the wild type and the rpoH1 mutant. Three classes of S. meliloti genes could be identified, which were transcriptionally regulated in an RpoH1-independent, an RpoH1-dependent or in a complex manner. The first class of S. meliloti genes, regulated in an RpoH1-independent manner, comprises the group of the exopolysaccharide I biosynthesis genes and also the group of genes involved in motility and flagellar biosynthesis. The second class of S. meliloti genes, regulated in an RpoH1-dependent manner, is composed of genes known from heat shock studies, like ibpA, grpE and groEL5, as well as genes involved in translation like tufA and rplC. Finally, the third class of S. meliloti genes was regulated in a complex manner, which indicates that besides sigma factor RpoH1, further regulation takes place. This was found to be the case for the genes dctA, ndvA and smc01505. Conclusions Clustering of time-course microarray data of S. meliloti wild type and sigma factor rpoH1 mutant allowed for the identification of gene clusters, each with a unique time-dependent expression pattern, as well as for the classification of genes according to their dependence on RpoH1 expression and regulation. This study provided clear evidence that the sigma factor RpoH1 plays a major role in pH stress response.
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110
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Fabra A, Castro S, Taurian T, Angelini J, Ibañez F, Dardanelli M, Tonelli M, Bianucci E, Valetti L. Interaction among Arachis hypogaea L. (peanut) and beneficial soil microorganisms: how much is it known? Crit Rev Microbiol 2010; 36:179-94. [PMID: 20214416 DOI: 10.3109/10408410903584863] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The leguminous crop Arachis hypogaea L. (peanut) is originally from South America and then was disseminated to tropical and subtropical regions. The dissemination of the crop resulted in peanut plants establishing a symbiotic nitrogen-fixing relationship with a wide diversity of indigenous soil bacteria. We present in this review, advances on the molecular basis for the crack-entry infection process involved in the peanut-rhizobia interaction, the diversity of rhizobial and fungal antagonistic bacteria associated with peanut plants, the effect of abiotic and biotic stresses on this interaction and the response of peanut to inoculation.
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Affiliation(s)
- A Fabra
- Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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111
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Shimizu T, Nakano T, Takamizawa D, Desaki Y, Ishii-Minami N, Nishizawa Y, Minami E, Okada K, Yamane H, Kaku H, Shibuya N. Two LysM receptor molecules, CEBiP and OsCERK1, cooperatively regulate chitin elicitor signaling in rice. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:204-14. [PMID: 21070404 PMCID: PMC2996852 DOI: 10.1111/j.1365-313x.2010.04324.x] [Citation(s) in RCA: 453] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Revised: 07/15/2010] [Accepted: 07/20/2010] [Indexed: 05/18/2023]
Abstract
Chitin is a major molecular pattern for various fungi, and its fragments, chitin oligosaccharides, are known to induce various defense responses in plant cells. A plasma membrane glycoprotein, CEBiP (chitin elicitor binding protein) and a receptor kinase, CERK1 (chitin elicitor receptor kinase) (also known as LysM-RLK1), were identified as critical components for chitin signaling in rice and Arabidopsis, respectively. However, it is not known whether each plant species requires both of these two types of molecules for chitin signaling, nor the relationships between these molecules in membrane signaling. We report here that rice cells require a LysM receptor-like kinase, OsCERK1, in addition to CEBiP, for chitin signaling. Knockdown of OsCERK1 resulted in marked suppression of the defense responses induced by chitin oligosaccharides, indicating that OsCERK1 is essential for chitin signaling in rice. The results of a yeast two-hybrid assay indicated that both CEBiP and OsCERK1 have the potential to form hetero- or homo-oligomers. Immunoprecipitation using a membrane preparation from rice cells treated with chitin oligosaccharides suggested the ligand-induced formation of a receptor complex containing both CEBiP and OsCERK1. Blue native PAGE and chemical cross-linking experiments also suggested that a major portion of CEBiP exists as homo-oligomers even in the absence of chitin oligosaccharides.
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Affiliation(s)
- Takeo Shimizu
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Takuto Nakano
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Daisuke Takamizawa
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Yoshitake Desaki
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Naoko Ishii-Minami
- Division of Plant Sciences, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Yoko Nishizawa
- Division of Plant Sciences, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Eiichi Minami
- Division of Plant Sciences, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Kazunori Okada
- Biotechnology Research Center, The University of Tokyo1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hisakazu Yamane
- Biotechnology Research Center, The University of Tokyo1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hanae Kaku
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
- *For correspondence (fax +81 44 934 7805; e-mail or fax +81 44 934 7039; e-mail )
| | - Naoto Shibuya
- Department of Life Sciences, Faculty of Agriculture, Meiji University1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
- *For correspondence (fax +81 44 934 7805; e-mail or fax +81 44 934 7039; e-mail )
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112
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Geddes BA, Pickering BS, Poysti NJ, Collins H, Yudistira H, Oresnik IJ. A locus necessary for the transport and catabolism of erythritol in Sinorhizobium meliloti. Microbiology (Reading) 2010; 156:2970-2981. [PMID: 20671019 DOI: 10.1099/mic.0.041905-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this work we have genetically defined an erythritol utilization locus in Sinorhizobium meliloti. A cosmid containing the locus was isolated by complementation of a transposon mutant and was subsequently mutagenized using Tn5 : : B20. The locus was found to consist of five transcriptional units, each of which was necessary for the utilization of erythritol. Genetic complementation experiments using genes putatively annotated as erythritol catabolic genes clearly showed that, of the 17 genes at this locus, six genes are not necessary for the utilization of erythritol as a sole carbon source. The remaining genes encode EryA, EryB, EryC and TpiB as well as an uncharacterized ABC-type transporter. Transport experiments using labelled erythritol showed that components of the ABC transporter are necessary for the uptake of erythritol. The locus also contains two regulators: EryD, a SorC class regulator, and SMc01615, a DeoR class regulator. Quantitative RT-PCR experiments showed that each of these regulators negatively regulates its own transcription. In addition, induction of the erythritol locus was dependent upon EryD and a product of erythritol catabolism. Further characterization of polar mutations revealed that in addition to erythritol, the locus contains determinants for adonitol and l-arabitol utilization. The context of the mutations suggests that the locus is important for both the transport and catabolism of adonitol and l-arabitol.
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Affiliation(s)
- Barney A. Geddes
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Brad S. Pickering
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Nathan J. Poysti
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Heather Collins
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Harry Yudistira
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ivan J. Oresnik
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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113
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Plasmids of the Rhizobiaceae and Their Role in Interbacterial and Transkingdom Interactions. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/978-3-642-14512-4_12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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114
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Karaś M, Russa R. Characterization of oligoglucan-containing products derived fromMesorhizobium lotiHAMBI 1148 murein after lysozyme digestion and β-elimination. ACTA CHROMATOGR 2010. [DOI: 10.1556/achrom.22.2010.2.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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115
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Koch M, Delmotte N, Rehrauer H, Vorholt JA, Pessi G, Hennecke H. Rhizobial adaptation to hosts, a new facet in the legume root-nodule symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:784-90. [PMID: 20459317 DOI: 10.1094/mpmi-23-6-0784] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rhizobia are able to infect legume roots, elicit root nodules, and live therein as endosymbiotic, nitrogen-fixing bacteroids. Host recognition and specificity are the results of early programming events in bacteria and plants, in which important signal molecules play key roles. Here, we introduce a new aspect of this symbiosis: the adaptive response to hosts. This refers to late events in bacteroids in which specific genes are transcribed and translated that help the endosymbionts to meet the disparate environmental requirements imposed by the hosts in which they live. The host-adaptation concept was elaborated with Bradyrhizobium japonicum and three different legumes (soybean, cowpea, and siratro). Transcriptomes and proteomes in root-nodule bacteroids were analyzed and compared, and genes and proteins were identified which are specifically induced in only one of the three hosts. We focused on those determinants that were congruent in the two data sets of host-specific transcripts and proteins: seven for soybean, five for siratro, and two for cowpea. One gene cluster for a predicted ABC-type transporter, differentially expressed in siratro, was deleted in B. japonicum. The respective mutant had a symbiotic defect on siratro rather than on soybean or cowpea. This result demonstrates the value of the applied approach and corroborates the host-specific adaptation concept.
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Affiliation(s)
- Marion Koch
- Institute of Microbiology, ETH, Zurich, Switzerland
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116
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Mandal SM, Chakraborty D, Dey S. Phenolic acids act as signaling molecules in plant-microbe symbioses. PLANT SIGNALING & BEHAVIOR 2010; 5:359-68. [PMID: 20400851 PMCID: PMC2958585 DOI: 10.4161/psb.5.4.10871] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Accepted: 12/07/2009] [Indexed: 05/18/2023]
Abstract
Phenolic acids are the main polyphenols made by plants. These compounds have diverse functions and are immensely important in plant-microbe interactions/symbiosis. Phenolic compounds act as signaling molecules in the initiation of legumerhizobia symbioses, establishment of arbuscular mycorrhizal symbioses and can act as agents in plant defense. Flavonoids are a diverse class of polyphenolic compounds that have received considerable attention as signaling molecules involved in plant-microbe interactions compared to the more widely distributed, simple phenolic acids; hydroxybenzoic and hydroxycinnamic acids, which are both derived from the general phenylpropanoid pathway. This review describes the well-known roles attributed to phenolic compounds as nod gene inducers of legume-rhizobia symbioses, their roles in induction of the GmGin1 gene in fungus for establishment of arbuscular mycorrhizal symbiosis, their roles in inducing vir gene expression in Agrobacterium, and their roles as defense molecules operating against soil borne pathogens that could have great implications for rhizospheric microbial ecology. Amongst plant phenolics we have a lack of knowledge concerning the roles of phenolic acids as signaling molecules beyond the relatively well-defined roles of flavonoids. This may be addressed through the use of plant mutants defective in phenolic acids biosynthesis or knock down target genes in future investigations.
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Affiliation(s)
- Santi M Mandal
- Department of Biotechnology; Indian Institute of Technology; Kharagpur, WB India
- The University of Texas Medical Branch; Galveston, TX USA
| | - Dipjyoti Chakraborty
- Plant Molecular & Cellular Genetics; Bose Institute; Kolkata, WB India
- Department of Bioscience & Biotechnology; Banasthali University; Rajasthan, India
| | - Satyahari Dey
- Department of Biotechnology; Indian Institute of Technology; Kharagpur, WB India
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117
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Delmotte N, Ahrens CH, Knief C, Qeli E, Koch M, Fischer HM, Vorholt JA, Hennecke H, Pessi G. An integrated proteomics and transcriptomics reference data set provides new insights into the Bradyrhizobium japonicum bacteroid metabolism in soybean root nodules. Proteomics 2010; 10:1391-400. [PMID: 20104621 DOI: 10.1002/pmic.200900710] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 12/03/2009] [Indexed: 11/07/2022]
Abstract
Bradyrhizobium japonicum, a gram-negative soil bacterium that establishes an N(2)-fixing symbiosis with its legume host soybean (Glycine max), has been used as a symbiosis model system. Using a sensitive geLC-MS/MS proteomics approach, we report the identification of 2315 B. japonicum strain USDA110 proteins (27.8% of the theoretical proteome) that are expressed 21 days post infection in symbiosis with soybean cultivated in growth chambers, substantially expanding the previously known symbiosis proteome. Integration of transcriptomics data generated under the same conditions (2780 expressed genes) allowed us to compile a comprehensive expression profile of B. japonicum during soybean symbiosis, which comprises 3587 genes/proteins (43% of the predicted B. japonicum genes/proteins). Analysis of this data set revealed both the biases and the complementarity of these global profiling technologies. A functional classification and pathway analysis showed that most of the proteins involved in carbon and nitrogen metabolism are expressed, including a complete set of tricarboxylic acid cycle enzymes, several gluconeogenesis and pentose phosphate pathway enzymes, as well as several proteins that were previously not considered to be present during symbiosis. Congruent results were obtained for B. japonicum bacteroids harvested from soybeans grown under field conditions.
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118
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Ferguson BJ, Indrasumunar A, Hayashi S, Lin MH, Lin YH, Reid DE, Gresshoff PM. Molecular analysis of legume nodule development and autoregulation. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:61-76. [PMID: 20074141 DOI: 10.1111/j.1744-7909.2010.00899.x] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Legumes are highly important food, feed and biofuel crops. With few exceptions, they can enter into an intricate symbiotic relationship with specific soil bacteria called rhizobia. This interaction results in the formation of a new root organ called the nodule in which the rhizobia convert atmospheric nitrogen gas into forms of nitrogen that are useable by the plant. The plant tightly controls the number of nodules it forms, via a complex root-to-shoot-to-root signaling loop called autoregulation of nodulation (AON). This regulatory process involves peptide hormones, receptor kinases and small metabolites. Using modern genetic and genomic techniques, many of the components required for nodule formation and AON have now been isolated. This review addresses these recent findings, presents detailed models of the nodulation and AON processes, and identifies gaps in our understanding of these process that have yet to be fully explained.
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Affiliation(s)
- Brett J Ferguson
- ARC Centre of Excellence for Integrative Legume Research, The University of Queensland, Brisbane, QLD 4072, Australia
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119
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Hata S, Kobae Y, Banba M. Interactions Between Plants and Arbuscular Mycorrhizal Fungi. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 281:1-48. [DOI: 10.1016/s1937-6448(10)81001-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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120
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Plant Defense Signaling from the Underground Primes Aboveground Defenses to Confer Enhanced Resistance in a Cost-Efficient Manner. PLANT COMMUNICATION FROM AN ECOLOGICAL PERSPECTIVE 2010. [DOI: 10.1007/978-3-642-12162-3_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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121
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Mutation in the lysA gene impairs the symbiotic properties of Mesorhizobium ciceri. Arch Microbiol 2009; 192:69-77. [PMID: 20020102 DOI: 10.1007/s00203-009-0527-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 09/18/2009] [Accepted: 11/03/2009] [Indexed: 10/20/2022]
Abstract
A Tn5-induced mutant of Mesorhizobium ciceri, TL28, requiring the amino acid lysine for growth on minimal medium was isolated and characterized. The Tn5 insertion in the mutant strain TL28 was located on a 6.8-kb EcoRI fragment of the chromosomal DNA. Complementation analysis with cloned DNA indicated that 1.269 kb of DNA of the 6.8-kb EcoRI fragment restored the wild-type phenotype of the lysine-requiring mutant. This region was further characterized by DNA sequence analysis and was shown to contain a coding sequence homologous to lysA gene of different bacteria. The lys (-) mutant TL28 was unable to elicit development of effective nodules on the roots of Cicer arietinum L. There was no detectable level of lysine in the root exudates of chickpea. However, addition of lysine to the plant growth medium restored the ability of the mutant to produce effective nodules with nitrogen fixation ability on the roots of C. arietinum.
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122
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Downie JA. The roles of extracellular proteins, polysaccharides and signals in the interactions of rhizobia with legume roots. FEMS Microbiol Rev 2009; 34:150-70. [PMID: 20070373 DOI: 10.1111/j.1574-6976.2009.00205.x] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Rhizobia adopt many different lifestyles including survival in soil, growth in the rhizosphere, attachment to root hairs and infection and growth within legume roots, both in infection threads and in nodules where they fix nitrogen. They are actively involved in extracellular signalling to their host legumes to initiate infection and nodule morphogenesis. Rhizobia also use quorum-sensing gene regulation via N-acyl-homoserine lactone signals and this can enhance their interaction with legumes as well as their survival under stress and their ability to induce conjugation of plasmids and symbiotic islands, thereby spreading their symbiotic capacity. They produce several surface polysaccharides that are critical for attachment and biofilm formation; some of these polysaccharides are specific for their growth on root hairs and can considerably enhance their ability to infect their host legumes. Different rhizobia use several different types of protein secretion mechanisms (Types I, III, IV, V and VI), and many of the secreted proteins play an important role in their interaction with plants. This review summarizes many of the aspects of the extracellular biology of rhizobia, in particular in relation to their symbiotic interaction with legumes.
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123
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Rodpothong P, Sullivan JT, Songsrirote K, Sumpton D, Cheung KWJT, Thomas-Oates J, Radutoiu S, Stougaard J, Ronson CW. Nodulation gene mutants of Mesorhizobium loti R7A-nodZ and nolL mutants have host-specific phenotypes on Lotus spp. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:1546-54. [PMID: 19888820 DOI: 10.1094/mpmi-22-12-1546] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Rhizobial Nod factors induce plant responses and facilitate bacterial infection, leading to the development of nitrogen-fixing root nodules on host legumes. Nodule initiation is highly dependent on Nod-factor structure and, hence, on at least some of the nodulation genes that encode Nod-factor production. Here, we report the effects of mutations in Mesorhizobium loti R7A nodulation genes on nodulation of four Lotus spp. and on Nod-factor structure. Most mutants, including a DeltanodSDeltanolO double mutant that produced Nod factors lacking the carbamoyl and possibly N-methyl groups on the nonreducing terminal residue, were unaffected for nodulation. R7ADeltanodZ and R7ADeltanolL mutants that produced Nod factors without the (acetyl)fucose on the reducing terminal residue had a host-specific phenotype, forming mainly uninfected nodule primordia on Lotus filicaulis and L. corniculatus and effective nodules with a delay on L. japonicus. The mutants also showed significantly reduced infection thread formation and Nin gene induction. In planta complementation experiments further suggested that the acetylfucose was important for balanced signaling in response to Nod factor by the L. japonicus NFR1/NFR5 receptors. Overall the results reveal differences in the sensitivity of plant perception with respect to signaling leading to root hair deformation and nodule primordium development versus infection thread formation and rhizobial entry.
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Affiliation(s)
- Patsarin Rodpothong
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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124
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Abstract
Biofilms are bacterial communities enclosed within an extracellular matrix of polysaccharides produced by the bacteria, which adhere to a living or an inert macrosurface. In nature, biofilms constitute a protected growth modality allowing bacteria to survive in hostile environments. Studies of environmental isolates have revealed a highly ordered, three-dimensional organization of the extracellular matrix, which has important implications for biofilm physiology. The zone of soil immediately surrounding a plant root where complex biological and ecological processes occur, termed rhizosphere, forms an environment that fulfills the requirements for biofilm formation, including sufficient moisture and supply of nutrients, which are provided by the plant. Biofilm formation on plants appears to be associated with symbiotic and pathogenic responses, but it is unclear how plants regulate the association. Biofilms function as structures resistant against stress factors such as desiccation, UV radiation, predation, and antibiosis, which help create protective niches for rhizobia. However, the role of biofilms in rhizobial-legume symbiosis remains to be clarified. Here, the mechanisms involved in bacterial biofilm formation and attachment on plant roots, and the relation of these mechanisms to rhizobial function and survival are reviewed.
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Affiliation(s)
- Luciana V Rinaudi
- Departamento de Biología Molecular, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
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125
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Van der Ent S, Van Wees SCM, Pieterse CMJ. Jasmonate signaling in plant interactions with resistance-inducing beneficial microbes. PHYTOCHEMISTRY 2009; 70:1581-8. [PMID: 19712950 DOI: 10.1016/j.phytochem.2009.06.009] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 06/05/2009] [Accepted: 06/11/2009] [Indexed: 05/18/2023]
Abstract
Beneficial soil-borne microorganisms can induce an enhanced defensive capacity in above-ground plant parts that provides protection against a broad spectrum of microbial pathogens and even insect herbivores. The phytohormones jasmonic acid (JA) and ethylene emerged as important regulators of this induced systemic resistance (ISR). ISR triggered by plant growth-promoting rhizobacteria and fungi is often not associated with enhanced biosynthesis of these hormones, nor with massive changes in defense-related gene expression. Instead, ISR-expressing plants are primed for enhanced defense. Priming is characterized by a faster and stronger expression of cellular defense responses that become activated only upon pathogen or insect attack, resulting in an enhanced level of resistance to the invader encountered. Recent advances in induced defense signaling research revealed regulators of ISR and suggest a model in which (JA)-related transcription factors play a central role in establishing the primed state.
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Affiliation(s)
- Sjoerd Van der Ent
- Plant-Microbe Interactions, Institute of Environmental Biology, Faculty of Science, Utrecht University, 3508 TB Utrecht, The Netherlands
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126
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Abstract
Large amounts of antibiotics used for human therapy, as well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur by the increased expression of genes that code for multidrug efflux pumps, extruding a wide range of drugs. This review discusses our current knowledge on the molecular mechanisms involved in both types of resistance.
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Affiliation(s)
- Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA.
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127
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Pretreatment of Clover Seeds with Nod Factors Improves Growth and Nodulation of Trifolium pratense. J Chem Ecol 2009; 35:479-87. [DOI: 10.1007/s10886-009-9620-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 03/26/2009] [Accepted: 03/27/2009] [Indexed: 10/20/2022]
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128
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129
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Bianco C, Defez R. Medicago truncatula improves salt tolerance when nodulated by an indole-3-acetic acid-overproducing Sinorhizobium meliloti strain. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3097-107. [PMID: 19436044 DOI: 10.1093/jxb/erp140] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The abiotic stress resistance of wild-type Sinorhizobium meliloti 1021 was compared with that of RD64, a derivative of the 1021 strain harbouring an additional pathway for the synthesis of indole-3-acetic acid (IAA), expressed in both free-living bacteria and bacteroids. It is shown here that the IAA-overproducing RD64 strain accumulated a higher level of trehalose as its endogenous osmolyte and showed an increased tolerance to several stress conditions (55 degrees C, 4 degrees C, UV-irradiation, 0.5 M NaCl, and pH 3). Medicago truncatula plants nodulated by RD64 (Mt-RD64) showed re-modulation of phytohormones, with a higher IAA content in nodules and roots and a decreased IAA level in shoots as compared with plants nodulated by the wild-type strain 1021 (Mt-1021). The response of nodulated M. truncatula plants to salt stress, when 0.3 M NaCl was applied, was analysed. For Mt-RD64 plants higher internal proline contents, almost unchanged hydrogen peroxide levels, and enhanced activity of antioxidant enzymes (superoxide dismutase, total peroxidase, glutathione reductase, and ascorbate peroxidase) were found compared with Mt-1021 plants. These results were positively correlated with reduced symptoms of senescence, lower expression of ethylene signalling genes, lower reduction of shoot dry weight, and better nitrogen-fixing capacity observed for these plants. Upon re-watering, after 0.3 M NaCl treatment, Mt-1021 plants almost die whereas Mt-RD64 plants showed visual signs of recovery. Finally, the shoot dry weight of Mt-RD64 plants treated with 0.15 M NaCl was not statistically different from that of Mt-1021 plants grown under non-stressed conditions.
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Affiliation(s)
- Carmen Bianco
- Institute of Genetics and Biophysics Adriano Buzzati Traverso, via P. Castellino 111, 80131 Naples, Italy
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130
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Chen C, Fan C, Gao M, Zhu H. Antiquity and function of CASTOR and POLLUX, the twin ion channel-encoding genes key to the evolution of root symbioses in plants. PLANT PHYSIOLOGY 2009; 149:306-17. [PMID: 18978069 PMCID: PMC2613720 DOI: 10.1104/pp.108.131540] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 10/28/2008] [Indexed: 05/18/2023]
Abstract
Root symbioses with arbuscular mycorrhizal fungi and rhizobial bacteria share a common signaling pathway in legumes. Among the common symbiosis genes are CASTOR and POLLUX, the twin homologous genes in Lotus japonicus that encode putative ion channel proteins. Here, we show that the orthologs of CASTOR and POLLUX are ubiquitously present and highly conserved in both legumes and nonlegumes. Using rice (Oryza sativa) as a study system, we employ reverse genetic tools (knockout mutants and RNA interference) to demonstrate that Os-CASTOR and Os-POLLUX are indispensable for mycorrhizal symbiosis in rice. Furthermore, a cross-species complementation test indicates that Os-POLLUX can restore nodulation, but not rhizobial infection, to a Medicago truncatula dmi1 mutant.
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MESH Headings
- Amino Acid Sequence
- DNA, Bacterial/genetics
- Evolution, Molecular
- Gene Expression Regulation, Plant
- Gene Knockout Techniques
- Genes, Plant
- Genetic Complementation Test
- Medicago truncatula/genetics
- Medicago truncatula/metabolism
- Medicago truncatula/microbiology
- Molecular Sequence Data
- Mutagenesis, Insertional
- Mycorrhizae/physiology
- Oryza/genetics
- Oryza/metabolism
- Oryza/microbiology
- Phylogeny
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/microbiology
- RNA Interference
- RNA, Plant/genetics
- Root Nodules, Plant/microbiology
- Sequence Alignment
- Symbiosis/genetics
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Affiliation(s)
- Caiyan Chen
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA
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131
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Bonilla I, Bolaños L. Mineral Nutrition for Legume-Rhizobia Symbiosis: B, Ca, N, P, S, K, Fe, Mo, Co, and Ni: A Review. SUSTAINABLE AGRICULTURE REVIEWS 2009. [DOI: 10.1007/978-1-4020-9654-9_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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132
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Hua C, Wang Y, Zheng X, Dou D, Zhang Z, Govers F, Wang Y. A Phytophthora sojae G-protein alpha subunit is involved in chemotaxis to soybean isoflavones. EUKARYOTIC CELL 2008; 7:2133-40. [PMID: 18931042 PMCID: PMC2593195 DOI: 10.1128/ec.00286-08] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 10/08/2008] [Indexed: 11/20/2022]
Abstract
For the soybean pathogen Phytophthora sojae, chemotaxis of zoospores to isoflavones is believed to be critical for recognition of the host and for initiating infection. However, the molecular mechanisms underlying this chemotaxis are largely unknown. To investigate the role of G-protein and calcium signaling in chemotaxis, we analyzed the expression of several genes known to be involved in these pathways and selected one that was specifically expressed in sporangia and zoospores but not in mycelium. This gene, named PsGPA1, is a single-copy gene in P. sojae and encodes a G-protein alpha subunit that shares 96% identity in amino acid sequence with that of Phytophthora infestans. To elucidate the function, expression of PsGPA1 was silenced by introducing antisense constructs into P. sojae. PsGPA1 silencing did not disturb hyphal growth or sporulation but severely affected zoospore behavior, including chemotaxis to the soybean isoflavone daidzein. Zoospore encystment and cyst germination were also altered, resulting in the inability of the PsGPA1-silenced mutants to infect soybean. In addition, the expressions of a calmodulin gene, PsCAM1, and two calcium- and calmodulin-dependent protein kinase genes, PsCMK3 and PsCMK4, were increased in the mutant zoospores, suggesting that PsGPA1 negatively regulates the calcium signaling pathways that are likely involved in zoospore chemotaxis.
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Affiliation(s)
- Chenlei Hua
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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133
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Somers E, Vanderleyden J, Srinivasan M. Rhizosphere Bacterial Signalling: A Love Parade Beneath Our Feet. Crit Rev Microbiol 2008; 30:205-40. [PMID: 15646398 DOI: 10.1080/10408410490468786] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Plant roots support the growth and activities of a wide variety of microorganisms that may have a profound effect on the growth and/or health of plants. Among these microorganisms, a high diversity of bacteria have been identified and categorized as deleterious, beneficial, or neutral with respect to the plant. The beneficial bacteria, termed plant growth-promoting rhizobacteria (PGPR), are widely studied by microbiologists and agronomists because of their potential in plant production. Azospirillum, a genus of versatile PGPR, is able to enhance the plant growth and yield of a wide range of economically important crops in different soils and climatic regions. Plant beneficial effects of Azospirillum have mainly been attributed to the production of phytohormones, nitrate reduction, and nitrogen fixation, which have been subject of extensive research throughout the years. These elaborate studies made Azospirillum one of the best-characterized genera of PGPR. However, the genetic and molecular determinants involved in the initial interaction between Azospirillum and plant roots are not yet fully understood. This review will mainly highlight the current knowledge on Azospirillum plant root interactions, in the context of preceding and ongoing research on the association between plants and plant growth-promoting rhizobacteria.
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Affiliation(s)
- E Somers
- Centre of Microbial and Plant Genetics, K U Leuven, Heverlee, Belgium.
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134
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Fauvart M, Michiels J. Rhizobial secreted proteins as determinants of host specificity in the rhizobium-legume symbiosis. FEMS Microbiol Lett 2008; 285:1-9. [PMID: 18616593 DOI: 10.1111/j.1574-6968.2008.01254.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Rhizobia are Gram-negative bacteria than can elicit the formation of specialized organs, called root nodules, on leguminous host plants. Upon infection of the nodules, they differentiate into nitrogen-fixing bacteroids. An elaborate signal exchange precedes the symbiotic interaction. In general, both rhizobia and host plants exhibit narrow specificity. Rhizobial factors contributing to this specificity include Nod factors and surface polysaccharides. It is becoming increasingly clear that protein secretion is important in determining the outcome of the interaction as well. This paper discusses our current understanding of the symbiotic role played by rhizobial secreted proteins, transported both by secretion systems that are of general use, such as the type I secretion system, and by specialized, host-targeting secretion systems, such as the type III, type IV and type VI secretion systems.
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Affiliation(s)
- Maarten Fauvart
- Centre of Microbial and Plant Genetics, K.U. Leuven, Leuven, Belgium
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135
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DeAngelis KM, Lindow SE, Firestone MK. Bacterial quorum sensing and nitrogen cycling in rhizosphere soil. FEMS Microbiol Ecol 2008; 66:197-207. [PMID: 18721146 DOI: 10.1111/j.1574-6941.2008.00550.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Plant photosynthate fuels carbon-limited microbial growth and activity, resulting in increased rhizosphere nitrogen (N) mineralization. Most soil organic nitrogen is macromolecular (chitin, protein, nucleotides); enzymatic depolymerization is likely rate limiting for plant nitrogen accumulation. Analyzing Avena (wild oat) planted in microcosms containing sieved field soil, we observed increased rhizosphere chitinase and protease-specific activities, bacterial cell densities, and dissolved organic nitrogen (DON) compared with bulk soil. Low-molecular-weight (MW) DON (<3000 Da) was undetectable in bulk soil but comprised 15% of rhizosphere DON. Extracellular enzyme production in many bacteria requires quorum sensing (QS), cell-density-dependent group behavior. Because proteobacteria are considered major rhizosphere colonizers, we assayed the proteobacterial QS signals N-acyl-homoserine lactones (AHLs), which were significantly increased in the rhizosphere. To investigate the linkage between soil signaling and nitrogen cycling, we characterized 533 bacterial isolates from Avena rhizosphere: 24% had chitinase or protease activity and AHL production; disruption of QS in seven of eight isolates disrupted enzyme activity. Many Alphaproteobacteria were newly found with QS-controlled extracellular enzyme activity. Enhanced specific activities of nitrogen-cycling enzymes accompanied by bacterial density-dependent behaviors in rhizosphere soil gives rise to the hypothesis that QS could be a control point in the complex process of rhizosphere nitrogen mineralization.
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Affiliation(s)
- Kristen M DeAngelis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
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136
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Sinorhizobium meliloti mutants deficient in phosphatidylserine decarboxylase accumulate phosphatidylserine and are strongly affected during symbiosis with alfalfa. J Bacteriol 2008; 190:6846-56. [PMID: 18708506 DOI: 10.1128/jb.00610-08] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sinorhizobium meliloti contains phosphatidylglycerol, cardiolipin, phosphatidylcholine, and phosphatidylethanolamine (PE) as major membrane lipids. PE is formed in two steps. In the first step, phosphatidylserine synthase (Pss) condenses serine with CDP-diglyceride to form phosphatidylserine (PS), and in the second step, PS is decarboxylated by phosphatidylserine decarboxylase (Psd) to form PE. In this study we identified the sinorhizobial psd gene coding for Psd. A sinorhizobial mutant deficient in psd is unable to form PE but accumulates the anionic phospholipid PS. Properties of PE-deficient mutants lacking either Pss or Psd were compared with those of the S. meliloti wild type. Whereas both PE-deficient mutants grew in a wild-type-like manner on many complex media, they were unable to grow on minimal medium containing high phosphate concentrations. Surprisingly, the psd-deficient mutant could grow on minimal medium containing low concentrations of inorganic phosphate, while the pss-deficient mutant could not. Addition of choline to the minimal medium rescued growth of the pss-deficient mutant, CS111, to some extent but inhibited growth of the psd-deficient mutant, MAV01. When the two distinct PE-deficient mutants were analyzed for their ability to form a nitrogen-fixing root nodule symbiosis with their alfalfa host plant, they behaved strikingly differently. The Pss-deficient mutant, CS111, initiated nodule formation at about the same time point as the wild type but did form about 30% fewer nodules than the wild type. In contrast, the PS-accumulating mutant, MAV01, initiated nodule formation much later than the wild type and formed 90% fewer nodules than the wild type. The few nodules formed by MAV01 seemed to be almost devoid of bacteria and were unable to fix nitrogen. Leaves of alfalfa plants inoculated with the mutant MAV01 were yellowish, indicating that the plants were starved for nitrogen. Therefore, changes in lipid composition, including the accumulation of bacterial PS, prevent the establishment of a nitrogen-fixing root nodule symbiosis.
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137
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Maj D, Wielbo J, Marek-Kozaczuk M, Skorupska A. Response to flavonoids as a factor influencing competitiveness and symbiotic activity of Rhizobium leguminosarum. Microbiol Res 2008; 165:50-60. [PMID: 18678476 DOI: 10.1016/j.micres.2008.06.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 06/03/2008] [Accepted: 06/30/2008] [Indexed: 10/21/2022]
Abstract
Flavonoids play a crucial role as signal molecules in promoting the formation of nodules by symbiotic bacteria commonly known as rhizobia. The early interaction between flavonoids and NodD regulatory protein activates nod gene transcription and the synthesis of Nod factor that initiates nodule primordium. In this study, we assessed response to flavonoids as factors influencing competitiveness of rhizobia and their symbiotic activity. Rhizobium leguminosarum nodule isolates belonging to three biovars, trifolii, viciae and phaseoli characterized earlier as competitive or uncompetitive relative to native rhizobia, were used. Investigating nodA promoter induction using plasmid lacZ fusion, we found that competitive strains more readily responded to a wide range of synthetic flavonoids and seed exudates in comparison to uncompetitive strains, albeit some exceptions were noticed. Of all the synthetic flavonoids and seed exudates studied, naringenin, hespertin and clover and vetch exudates were the most effective inducers of nodA promoter in competitive strains. Only one of the nine examined uncompetitive strains was highly induced by clover seed exudate. Subsequently, the effect of preinduction of R. leguminosarum bv. trifolii with clover exudate was assessed. Out of 18 pre-activated strains, nine strains (including competitive ones) increased clover wet mass of shoots and nodule number when used as inoculants. Our results demonstrate a plausible approach of isolating and characterizing flavonoid-responsive field isolates that could be further developed into relevant legume inoculants.
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Affiliation(s)
- Dominika Maj
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19 st., 20-033 Lublin, Poland
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138
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Zehner S, Schober G, Wenzel M, Lang K, Göttfert M. Expression of the Bradyrhizobium japonicum type III secretion system in legume nodules and analysis of the associated tts box promoter. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:1087-93. [PMID: 18616405 DOI: 10.1094/mpmi-21-8-1087] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In Bradyrhizobium japonicum, as in some other rhizobia, symbiotic efficiency is influenced by a type III secretion system (T3SS). Most genes encoding the transport machinery and secreted proteins are preceded by a conserved 30-bp motif, the type-three secretion (tts) box. In this study, we found that regions downstream of 34 tts boxes are transcribed. For nopB, nopL, and gunA2, the transcriptional start sites were found to be 12, 11, and 10 bp downstream of their tts boxes, respectively. The deletion of this motif or modification of two or more conserved residues strongly reduced expression of nopB. This indicates that the tts box is an essential promoter element. Data obtained with lacZ reporter gene fusions of five genes preceded by a tts box (gunA2, nopB, rhcV, nopL, and blr1806) revealed that they are expressed in 4-week-old nodules of Macroptilium atropurpureum. These data suggest that the T3SS is active in mature nitrogen-fixing nodules. The two-component response regulator TtsI is required for the expression of rhcV, nopL, and blr1806 in bacteroids. Staining of inoculated roots showed that nopB is also expressed in early infection stages.
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Affiliation(s)
- Susanne Zehner
- Institute of Genetics, Dresden University of Technology, Helmholtzstrasse 10, Dresden, Germany.
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139
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Van Wees SCM, Van der Ent S, Pieterse CMJ. Plant immune responses triggered by beneficial microbes. CURRENT OPINION IN PLANT BIOLOGY 2008; 11:443-8. [PMID: 18585955 DOI: 10.1016/j.pbi.2008.05.005] [Citation(s) in RCA: 390] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Revised: 05/13/2008] [Accepted: 05/16/2008] [Indexed: 05/18/2023]
Abstract
Beneficial soil-borne microorganisms, such as plant growth promoting rhizobacteria and mycorrhizal fungi, can improve plant performance by inducing systemic defense responses that confer broad-spectrum resistance to plant pathogens and even insect herbivores. Different beneficial microbe-associated molecular patterns (MAMPs) are recognized by the plant, which results in a mild, but effective activation of the plant immune responses in systemic tissues. Evidence is accumulating that systemic resistance induced by different beneficials is regulated by similar jasmonate-dependent and ethylene-dependent signaling pathways and is associated with priming for enhanced defense.
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Affiliation(s)
- Saskia C M Van Wees
- Plant-Microbe Interactions, Institute of Environmental Biology, Faculty of Science, Utrecht University, P.O. Box 800.56, 3508 TB Utrecht, The Netherlands
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140
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Abstract
It was found that S. meliloti strain SmA818, which is cured of pSymA, could not grow on defined medium containing only formate and bicarbonate as carbon sources. Growth experiments showed that Rm1021 was capable of formate/bicarbonate-dependent growth, suggesting that it was capable of autotrophic-type growth. The annotated genome of S. meliloti Rm1021 contains three formate dehydrogenase genes. A systematic disruption of each of the three formate dehydrogenase genes, as well as the genes encoding determinants of the Calvin-Benson-Bassham, cycle was carried out to determine which of these determinants played a role in growth on this defined medium. The results showed that S. meliloti is capable of formate-dependent autotrophic growth. Formate-dependent autotrophic growth is dependent on the presence of the chromosomally located fdsABCDG operon, as well as the cbb operon carried by pSymB. Growth was also dependent on the presence of either of the two triose-phosphate isomerase genes (tpiA or tpiB) that are found in the genome. In addition, it was found that fdoGHI carried by pSymA encodes a formate dehydrogenase that allows Rm1021 to carry out formate-dependent respiration. Taken together, the data allow us to present a model of how S. meliloti can grow on defined medium containing only formate and bicarbonate as carbon sources.
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141
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Ampomah OY, Jensen JB, Bhuvaneswari TV. Lack of trehalose catabolism in Sinorhizobium species increases their nodulation competitiveness on certain host genotypes. THE NEW PHYTOLOGIST 2008; 179:495-504. [PMID: 19086182 DOI: 10.1111/j.1469-8137.2008.02460.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The role of host and bacterial genotypes in determining the competitiveness of trehalose utilization mutants of Sinorhizobium meliloti and Sinorhizobium medicae was investigated here. Trehalose utilization mutants of S. meliloti and S. medicae were obtained by mutagenesis of their trehalose utilization gene thuB. The mutant strains and the wild type were coinoculated on three cultivars of alfalfa (Medicago sativa) and two cultivars of Medicago truncatula and assessed for competitiveness in root colonization, and nodule occupancy. The thuB mutants formed more nodules than their parent strains on two of the three alfalfa lines tested and on one of the two M. truncatula lines tested. They were not more competitive on the other alfalfa and M. truncatula lines. Their competitiveness for nodule occupancy did not correlate positively with their ability to colonize these roots but correlated with the extent of thuB induction in the infection threads. Induction of thuB was shown to be dependent on the concentration of trehalose in the environment. These results suggest a direct role for host trehalose metabolism in early plant-symbiont interactions and show that the ability to manage host-induced stresses during infection, rather than the ability to colonize the root, is critical for competitive nodulation.
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Affiliation(s)
- Osei Yaw Ampomah
- Department of Biology, Faculty of Science, University of Tromsø, N-9037, Norway
| | - John Beck Jensen
- Department of Biology, Faculty of Science, University of Tromsø, N-9037, Norway
| | - T V Bhuvaneswari
- Department of Biology, Faculty of Science, University of Tromsø, N-9037, Norway
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142
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Hayashi S, Gresshoff PM, Kinkema M. Molecular analysis of lipoxygenases associated with nodule development in soybean. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:843-53. [PMID: 18624647 DOI: 10.1094/mpmi-21-6-0843] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We utilized transcriptional profiling to identify genes associated with nodule development in soybean. Many of the candidate genes were predicted to be involved in processes such as defense, metabolism, transcriptional regulation, oxidation, or iron storage. Here, we describe the detailed characterization of one specific class of genes that encode the enzyme lipoxygenase (LOX). The LOX9 and LOX10 genes identified by microarray analysis represent novel soybean LOXs expressed in developing nodules. LOX expression during nodulation was relatively complex, with at least eight different LOX genes expressed in soybean nodules. Histochemical analyses utilizing LOX9 promoter::beta-glucuronidase (GUS) fusion constructs in transgenic soybean hairy roots suggest that this gene is involved in the growth and development of specific cells within the root and nodules. In soybean roots, LOX9 was expressed specifically in the developing phloem. In nodules, the expression of LOX9 was correlated with the development of cells in the vasculature and lenticels. The use of RNAi in transgenic hairy roots reduced LOX expression by approximately 95%. Despite this significant reduction in LOX expression, there was no detectable effect on the development of roots or nodules. Our findings are discussed with respect to the potential function of LOXs in nodulation.
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Affiliation(s)
- Satomi Hayashi
- Australian Research Council Centre of Excellence for Integrative Legume Research, The University of Queensland, St. Lucia, QLD 4072, Australia
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143
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Constantin GD, Grønlund M, Johansen IE, Stougaard J, Lund OS. Virus-induced gene silencing (VIGS) as a reverse genetic tool to study development of symbiotic root nodules. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:720-7. [PMID: 18624636 DOI: 10.1094/mpmi-21-6-0720] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Virus-induced gene silencing (VIGS) can provide a shortcut to plants with altered expression of specific genes. Here, we report that VIGS of the Nodule inception gene (Nin) can alter the nodulation phenotype and Nin gene expression in Pisum sativum. PsNin was chosen as target because of the distinct non-nodulating phenotype of nin mutants in P. sativum, Lotus japonicus, and Medicago truncatula. The vector based on Pea early browning virus (PEBV) was engineered to carry one of three nonoverlapping fragments (PsNinA, PsNinB, and PsNinC) derived from the PsNin cDNA. Vector inoculation was mediated by agroinfiltration and, 2 weeks later, a Rhizobium leguminosarum bv. viceae culture was added in order to induce root nodulation. At this time point, it was estimated that systemic silencing was established because leaves of reference plants inoculated with PEBV carrying a fragment of Phytoene desaturase displayed photo bleaching. Three weeks after Rhizobium spp. application, plants inoculated with a control vector nodulated normally, whereas nodulation was almost eliminated in plants inoculated with a vector carrying PsNinA and PsNinC. For plants inoculated with a vector carrying PsNinB, nodulation was reduced by at least 45%. Down-regulation of PsNin transcripts in plants inoculated with vectors carrying PsNin cDNA fragments was confirmed and these plants displayed a relative increase in the root/shoot ratio, as expected if nitrogen fixation had been impaired.
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MESH Headings
- Gene Silencing
- Genetic Vectors/genetics
- Models, Biological
- Nitrogen Fixation
- Pisum sativum/genetics
- Pisum sativum/microbiology
- Pisum sativum/virology
- Phenotype
- Plant Proteins/genetics
- Plant Proteins/physiology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Plants, Genetically Modified/microbiology
- Protein Isoforms/genetics
- Protein Isoforms/physiology
- RNA Viruses/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Rhizobium/growth & development
- Root Nodules, Plant/genetics
- Root Nodules, Plant/growth & development
- Root Nodules, Plant/microbiology
- Symbiosis/genetics
- Symbiosis/physiology
- Transcription, Genetic
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Affiliation(s)
- G D Constantin
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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144
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Chovanec P, Hovorka O, Novák K. Visualization of symbiotic tissue in intact root nodules of Vicia tetrasperma using GFP-marked Rhizobium leguminosarum bv. viciae. Folia Microbiol (Praha) 2008; 53:139-46. [PMID: 18500633 DOI: 10.1007/s12223-008-0020-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 09/25/2007] [Indexed: 11/29/2022]
Abstract
In rhizobial symbiosis with legume plant hosts, the symbiotic tissue in the root nodules of indeterminate type is localized to the basal part of the nodule where the symbiotic zones contain infected cells (IC) interspersed with uninfected cells (UC) that are devoid of rhizobia. Although IC are easily distinguished in nodule sections using standard histochemical techniques, their observation in intact nodules is hampered by nodule tissue characteristics. Tagging of Rhizobium leguminosarum bv. viciae strain 128C30 with a constitutively expressed gene for green fluorescent protein (nonshifted mutant form cycle3) in combination with the advantages of the tiny nodules formed by Vicia tetrasperma (L.) SCHREB . allowed for vital observation of symbiotic tissue using fluorescence microscopy. Separation of a red-shifted background channel and digital image stacking along z-axis enabled us to construct a nodule image in a classical fluorescence microscopy of nodules exceeding 1 mm in diameter. In parallel, visualization of nodule bacteria inside the symbiotic tissue by confocal microscopy at the excitation wavelength 488 nm clearly distinguished IC/UC pattern in the nodule virtual sections and revealed red-shifted fluorescence of nonrhizobial origin. This signal was located on the periphery of IC and increased with their degradation, thus suggesting accumulation of secondary metabolites, presumably flavonoids. The simultaneous detection of bacteria and secondary metabolites can be used for monitoring changes to intact nodule physiology in the model legumes. The advantage of V. tetrasperma as a suggested laboratory model for pea cross-inoculation group has been demonstrated.
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Affiliation(s)
- P Chovanec
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague, Czechia
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145
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Townsend GE, Keating DH. Identification and characterization of KpsS, a novel polysaccharide sulphotransferase in Mesorhizobium loti. Mol Microbiol 2008; 68:1149-64. [PMID: 18430142 DOI: 10.1111/j.1365-2958.2008.06215.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plants enter into symbiotic relationships with bacteria that allow survival in nutrient-limiting environments. The bacterium Mesorhizobium loti enters into a symbiosis with the legume host, Lotus japonicus, which results in the formation of novel plant structures called root nodules. The bacteria colonize the nodules, and are internalized into the cytoplasm of the plant cells, where they reduce molecular dinitrogen for the plant. Symbiosis between M. loti and L. japonicus requires bacterial synthesis of secreted and cell-surface polysaccharides. We previously reported the identification of an unusual sulphate-modified form of capsular polysaccharide (KPS) in M. loti. To better understand the physiological function of sulphated KPS, we isolated the sulphotransferase responsible for KPS sulphation from M. loti extracts, determined its amino acid sequence and identified the corresponding M. loti open reading frame, mll7563 (which we have named kpsS). We demonstrated that partially purified KpsS functions as a fucosyl sulphotransferase in vitro. Furthermore, mutants deficient for this gene exhibit a lack of KPS sulphation and a decreased rate of nodule formation on L. japonicus. Interestingly, the kpsS gene product shares no significant amino acid similarity with previously identified sulphotransferases, but exhibited sequence identity to open reading frames of unknown function in diverse bacteria that interact with eukaryotes.
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Affiliation(s)
- Guy E Townsend
- Department of Microbiology and Immunology, Loyola University, Chicago, IL, USA
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146
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Functional nodFE genes are present in Sinorhizobium sp. strain MUS10, a symbiont of the tropical legume Sesbania rostrata. Appl Environ Microbiol 2008; 74:2921-3. [PMID: 18326678 DOI: 10.1128/aem.00075-08] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have cloned the nodFE operon from Sinorhizobium sp. strain MUS10. MUS10 NodF shows sequence homology to acyl carrier protein and enables an S. meliloti nodF mutant to effectively nodulate alfalfa. Our results demonstrate the occurrence of nodFE in a symbiont that nodulates a legume host not belonging to the galegoid group.
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147
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Wielbo J, Skorupska A. Influence of phosphate and ammonia on the growth, exopolysaccharide production and symbiosis of Rhizobium leguminosarum bv. trifolii TA1 with clover (Trifolium pratense). ACTA BIOLOGICA HUNGARICA 2008; 59:115-27. [PMID: 18401950 DOI: 10.1556/abiol.59.2008.1.10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Rhizobium-legume interaction is sensitive to a number of environmental factors, among which phosphate (Pi) and ammonium availability are the most important. We investigated the effect of Pi and ammonia concentration on exopolysaccharide production and symbiosis Trifolium pratense with Rhizobium leguminosarum bv. trifolii TA1 (RtTA1). The optimal Pi concentration in the bacterial growth medium for RtTA1 growth and exopolysaccharide production was in the range from 0.9 mM to 8.1 mM. Independently of Pi concentration, ammonium (NH4Cl) concentration above 8.1 mM in the culture medium significantly decreased EPS production, indicating a regulatory role of this nutrient on the EPS production in the RtTA1 strain. Pi availability has a beneficial effect on both partners of symbiosis. Pi concentration in the plant medium in the range from 1.7 mM to 5 mM was optimal for nodule formation, nodule occupancy and nitrogen fixation ability. Despite of T. pratense cv. Bryza tolerance on high Pi concentration, 20 mM Pi occurs to be nearly phytotoxic, which negatively affects almost all symbiotic parameters. Large amounts of starch were accumulated in the nodules formed by clover grown on medium containing high Pi concentration.
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Affiliation(s)
- J Wielbo
- Department of General Microbiology, M. Curie-Skłodowska University, Lublin, Poland.
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148
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D'Antuono AL, Ott T, Krusell L, Voroshilova V, Ugalde RA, Udvardi M, Lepek VC. Defects in rhizobial cyclic glucan and lipopolysaccharide synthesis alter legume gene expression during nodule development. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:50-60. [PMID: 18052882 DOI: 10.1094/mpmi-21-1-0050] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
cDNA array technology was used to compare transcriptome profiles of Lotus japonicus roots inoculated with a Mesorhizobium loti wild-type and two mutant strains affected in cyclic beta(1-2) glucan synthesis (cgs) and in lipopolysaccharide synthesis (lpsbeta2). Expression of genes associated with the development of a fully functional nodule was significantly affected in plants inoculated with the cgs mutant. Array results also revealed that induction of marker genes for nodule development was delayed when plants were inoculated with the lpsbeta2 mutant. Quantitative real-time reverse-transcriptase polymerase chain reaction was used to quantify gene expression of a subset of genes involved in plant defense response, redox metabolism, or genes that encode for nodulins. The majority of the genes analyzed in this study were more highly expressed in roots inoculated with the wild type compared with those inoculated with the cgs mutant strain. Some of the genes exhibited a transient increase in transcript levels during intermediate steps of normal nodule development while others displayed induced expression during the final steps of nodule development. Ineffective nodules induced by the glucan mutant showed higher expression of phenylalanine ammonia lyase than wild-type nodules. Differences in expression pattern of genes involved in early recognition and signaling were observed in plants inoculated with the M. loti mutant strain affected in the synthesis of cyclic glucan.
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Affiliation(s)
- Alejandra L D'Antuono
- Instituto de Investigaciones Biotecnológicas, INTECH, Universidad Nacional de General San Martín, CONICET, Buenos Aires, Argentina
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149
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Kuhn S, Stiens M, Pühler A, Schlüter A. Prevalence of pSmeSM11a-like plasmids in indigenous Sinorhizobium meliloti strains isolated in the course of a field release experiment with genetically modified S. meliloti strains. FEMS Microbiol Ecol 2008; 63:118-31. [DOI: 10.1111/j.1574-6941.2007.00399.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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150
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Abstract
Rhizobial bacteria colonize legume roots for the purpose of biological nitrogen fixation. A complex series of events, coordinated by host and bacterial signal molecules, underlie the development of this symbiotic interaction. Rhizobia elicit de novo formation of a novel root organ within which they establish a chronic intracellular infection. Legumes permit rhizobia to invade these root tissues while exerting control over the infection process. Once rhizobia gain intracellular access to their host, legumes also strongly influence the process of bacterial differentiation that is required for nitrogen fixation. Even so, symbiotic rhizobia play an active role in promoting their goal of host invasion and chronic persistence by producing a variety of signal molecules that elicit changes in host gene expression. In particular, rhizobia appear to advocate for their access to the host by producing a variety of signal molecules capable of suppressing a general pathogen defense response.
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Affiliation(s)
- Katherine E. Gibson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Hajime Kobayashi
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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