Overexpression of the arginine decarboxylase gene promotes the symbiotic interaction Medicago truncatula-Sinorhizobium meliloti and induces the accumulation of proline and spermine in nodules under salt stress conditions

Nitric oxide (NO) is involved in diverse physiological processes in plants, including growth, development, response to pathogens, and interactions with beneficial microorganisms. In this work, a dedicated microarray representing the widest database available of NO-related transcripts in plants has been produced with 999 genes identified by a cDNA amplified fragment length polymorphism analysis as modulated in Medicago truncatula roots treated with two NO donors. The microarray then was used to monitor the expression of NO-responsive genes in M. truncatula during the incompatible interaction with the foliar pathogen Colletotrichum trifolii race 1 and during the symbiotic interaction with Sinorhizobium meliloti 1021. A wide modulation of NO-related genes has been detected during the hypersensitive reaction or during nodule formation and is discussed with special emphasis on the physiological relevance of these genes in the context of the two biotic interactions. This work clearly shows that NO-responsive genes behave differently depending on the plant organ and on the type of interaction, strengthening the need to consider regulatory networks, including different signaling molecules.

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The Medicago truncatula N5 Gene Encoding a Root-Specific Lipid Transfer Protein Is Required for the Symbiotic Interaction with Sinorhizobium meliloti

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-22-12-1577 ◽

2009 ◽

Vol 22 (12) ◽

pp. 1577-1587 ◽

Cited By ~ 33

Author(s):

Youry Pii ◽

Alessandra Astegno ◽

Elisa Peroni ◽

Massimo Zaccardelli ◽

Tiziana Pandolfini ◽

...

Keyword(s):

Medicago Truncatula ◽

Sinorhizobium Meliloti ◽

Lipid Transfer Protein ◽

Symbiotic Association ◽

Lipid Transfer ◽

Symbiotic Interaction ◽

Transgenic Roots ◽

Transfer Protein ◽

Small Proteins

The Medicago truncatula N5 gene is induced in roots after Sinorhizobium meliloti infection and it codes for a putative lipid transfer protein (LTP), a family of plant small proteins capable of binding and transferring lipids between membranes in vitro. Various biological roles for plant LTP in vivo have been proposed, including defense against pathogens and modulation of plant development. The aim of this study was to shed light on the role of MtN5 in the symbiotic interaction between M. truncatula and S. meliloti. MtN5 cDNA was cloned and the mature MtN5 protein expressed in Escherichia coli. The lipid binding capacity and antimicrobial activity of the recombinant MtN5 protein were tested in vitro. MtN5 showed the capacity to bind lysophospholipids and to inhibit M. truncatula pathogens and symbiont growth in vitro. Furthermore, MtN5 was upregulated in roots after infection with either the fungal pathogen Fusarium semitectum or the symbiont S. meliloti. Upon S. meliloti infection, MtN5 was induced starting from 1 day after inoculation (dpi). It reached the highest concentration at 3 dpi and it was localized in the mature nodules. MtN5-silenced roots were impaired in nodulation, showing a 50% of reduction in the number of nodules compared with control roots. On the other hand, transgenic roots overexpressing MtN5 developed threefold more nodules with respect to control roots. Here, we demonstrate that MtN5 possesses biochemical features typical of LTP and that it is required for the successful symbiotic association between M. truncatula and S. meliloti.

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Expression Dynamics of the Medicago truncatula Transcriptome during the Symbiotic Interaction with Sinorhizobium meliloti: Which Role for Nitric Oxide?

PLANT PHYSIOLOGY ◽

10.1104/pp.112.208538 ◽

2012 ◽

Vol 161 (1) ◽

pp. 425-439 ◽

Cited By ~ 65

Author(s):

Alexandre Boscari ◽

Jennifer del Giudice ◽

Alberto Ferrarini ◽

Luca Venturini ◽

Anne-Lise Zaffini ◽

...

Keyword(s):

Nitric Oxide ◽

Medicago Truncatula ◽

Sinorhizobium Meliloti ◽

Symbiotic Interaction

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Identification of New Potential Regulators of the Medicago truncatula—Sinorhizobium meliloti Symbiosis Using a Large-Scale Suppression Subtractive Hybridization Approach

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-3-0321 ◽

2007 ◽

Vol 20 (3) ◽

pp. 321-332 ◽

Cited By ~ 28

Author(s):

Laurence Godiard ◽

Andreas Niebel ◽

Fabienne Micheli ◽

Jérôme Gouzy ◽

Thomas Ott ◽

...

Keyword(s):

Signal Transduction ◽

Suppression Subtractive Hybridization ◽

Medicago Truncatula ◽

Large Scale ◽

Sinorhizobium Meliloti ◽

Zinc Finger Protein ◽

Gene Clusters ◽

Subtractive Hybridization ◽

Symbiotic Interaction ◽

Genes Encoding

We set up a large-scale suppression subtractive hybridization (SSH) approach to identify Medicago truncatula genes differentially expressed at different stages of the symbiotic interaction with Sinorhizobium meliloti, with a particular interest for regulatory genes. We constructed 7 SSH libraries covering successive stages from Nod factor signal transduction to S. meliloti infection, nodule organogenesis, and functioning. Over 26,000 clones were differentially screened by two rounds of macroarray hybridizations. In all, 3,340 clones, corresponding to genes whose expression was potentially affected, were selected, sequenced, and ordered into 2,107 tentative gene clusters, including 767 MtS clusters corresponding to new M. truncatula genes. In total, 52 genes encoding potential regulatory proteins, including transcription factors (TFs) and other elements of signal transduction cascades, were identified. The expression pattern of some of them was analyzed by quantitative reverse-transcription polymerase chain reaction in wild-type and in Nod¯ M. truncatula mutants blocked before or after S. meliloti infection. Three genes, coding for TFs of the bHLH and WRKY families and a C2H2 zinc-finger protein, respectively, were found to be upregulated, following S. meliloti inoculation, in the infection-defective mutant lin, whereas the bHLH gene also was expressed in the root-hair-curling mutant hcl. The potential role of these genes in early symbiotic steps is discussed.

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DNA double-strand break repair is involved in desiccation resistance of Sinorhizobium meliloti, but is not essential for its symbiotic interaction with Medicago truncatula

Microbiology ◽

10.1099/mic.0.000400 ◽

2017 ◽

Vol 163 (3) ◽

pp. 333-342 ◽

Cited By ~ 10

Author(s):

Pierre Dupuy ◽

Benjamin Gourion ◽

Laurent Sauviac ◽

Claude Bruand

Keyword(s):

Medicago Truncatula ◽

Sinorhizobium Meliloti ◽

Strand Break ◽

Double Strand Break ◽

Double Strand Break Repair ◽

Desiccation Resistance ◽

Symbiotic Interaction ◽

Dna Double Strand Break ◽

Break Repair

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Faculty Opinions recommendation of The Medicago truncatula CRE1 cytokinin receptor regulates lateral root development and early symbiotic interaction with Sinorhizobium meliloti.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1092195.545586 ◽

2007 ◽

Author(s):

Ton Bisseling

Keyword(s):

Medicago Truncatula ◽

Root Development ◽

Lateral Root ◽

Sinorhizobium Meliloti ◽

Symbiotic Interaction ◽

Cytokinin Receptor ◽

Lateral Root Development

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(Homo)glutathione Depletion Modulates Host Gene Expression during the Symbiotic Interaction between Medicago truncatula and Sinorhizobium meliloti

PLANT PHYSIOLOGY ◽

10.1104/pp.109.142034 ◽

2009 ◽

Vol 151 (3) ◽

pp. 1186-1196 ◽

Cited By ~ 21

Author(s):

Chiara Pucciariello ◽

Gilles Innocenti ◽

Willem Van de Velde ◽

Annie Lambert ◽

Julie Hopkins ◽

...

Keyword(s):

Gene Expression ◽

Medicago Truncatula ◽

Sinorhizobium Meliloti ◽

Host Gene ◽

Glutathione Depletion ◽

Host Gene Expression ◽

Symbiotic Interaction

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OnfD, an AraC-Type Transcriptional Regulator Encoded by Rhizobium tropici CIAT 899 and Involved in Nod Factor Synthesis and Symbiosis

Applied and Environmental Microbiology ◽

10.1128/aem.01297-20 ◽

2020 ◽

Vol 86 (19) ◽

Author(s):

Pablo del Cerro ◽

Paula Ayala-García ◽

Pablo Buzón ◽

Roger Castells-Graells ◽

Francisco Javier López-Baena ◽

...

Keyword(s):

Salt Stress ◽

Osmotic Stress ◽

Transcriptional Activation ◽

Structural Model ◽

Stress Conditions ◽

Broad Host Range ◽

Rhizobial Strain ◽

Rhizobium Tropici ◽

Symbiotic Interaction ◽

Content Type

ABSTRACT Rhizobium tropici CIAT 899 is a broad-host-range rhizobial strain that establishes symbiotic interactions with legumes and tolerates different environmental stresses such as heat, acidity, or salinity. This rhizobial strain produces a wide variety of symbiotically active nodulation factors (NF) induced not only by the presence of plant-released flavonoids but also under osmotic stress conditions through the LysR-type transcriptional regulators NodD1 (flavonoids) and NodD2 (osmotic stress). However, the activation of NodD2 under high-osmotic-stress conditions remains elusive. Here, we have studied the role of a new AraC-type regulator (named as OnfD) in the symbiotic interaction of R. tropici CIAT 899 with Phaseolus vulgaris and Lotus plants. We determined that OnfD is required under salt stress conditions for the transcriptional activation of the nodulation genes and therefore the synthesis and export of NF, which are required for a successful symbiosis with P. vulgaris. Moreover, using bacterial two-hybrid analysis, we demonstrated that the OnfD and NodD2 proteins form homodimers and OnfD/NodD2 form heterodimers, which could be involved in the production of NF in the presence of osmotic stress conditions since both regulators are required for NF synthesis in the presence of salt. A structural model of OnfD is presented and discussed. IMPORTANCE The synthesis and export of rhizobial NF are mediated by a conserved group of LysR-type regulators, the NodD proteins. Here, we have demonstrated that a non-LysR-type regulator, an AraC-type protein, is required for the transcriptional activation of symbiotic genes and for the synthesis of symbiotically active NF under salt stress conditions.

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