Genome-wide annotation of remorins, a plant-specific protein family: evolutionary and functional perspectives

Genome-wide annotation of remorins, a plant-specific protein family: evolutionary and functional perspective

CCAAT-box binding transcription factors in plants: Y so many?

In the review article ‘CCAAT-box binding transcription factors in plants: Y so many’ by Tom Laloum, Stéphane De Mita, Pascal Gamas, Maël Baudin, and Andreas Niebel, which was published in the March 2013 issue of Trends in Plant Science, the procedure used for reconstructing the phylogenetic trees in Figure 2 was incorrectly described. The sentence ‘The tree has been reconstructed using maximum likelihood under the general time-reversible model as implemented in the PhyML software’ should read ‘The tree has been reconstructed using maximum likelihood under the LG model as implemented in the PhyML software’. This change to the figure legend does not affect the conclusions mentioned in the paper. Below is the corrected version of Figure 2: (voir PDF) Erratum, Trends in Plant Science, volume 18, issue 10, 594-595Transcription factors belonging to the CCAAT-box binding factor family (also known as the Nuclear Factor Y) are present in all higher eukaryotes. Studies in plants have revealed that each subunit of this heterotrimeric transcription factor is encoded by a gene belonging to a multigene family allowing a considerable modularity. In this review, we focus on recent findings concerning the expression patterns and potential functions of different members of these NF-Y protein families using a phylogenetic approach. During the course of evolution plant CCAAT-box binding factors seem to have diversified into at least two main groups. The first group has more general expression patterns and/or functions whereas the second group has acquired more specific expression patterns and/or functions and could play key roles in specific pathways

Nod Factor Binding Sites : Receptors or Acceptors.

International audienceNod factors are the rhizobial determinants of nodulation and host specificity in the legume-rhizobia symbiosis. These lipochitooligosacccharides (LCOs) are capable of eliciting various responses on the roots of legumes at pico-micromolar concentrations, suggesting that they are perceived by specific receptors in legumes. By using radiolabelled Nod factors we have been able to characterise different types of binding sites in legumes. The relevance of these Nod factors binding proteins as putative receptors will be discussed

Effets biologiques précoces et perception des facteurs Nod au cours de la symbiose Rhizobium-Légumineuses.

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Identification of new potential regulators of the [i]Medicago truncatula[/i]–[i]Sinorhizobium meliloti[/i] symbiosis using a large-scale suppression subtractive hybridization approach

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

Perception of lipo-chitooligosaccharidic Nod factors in the legume-Rhizobia symbiosis : studies on Medicago Nod factor binding sites.

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Nod factor perception and transduction in the legume-rhizobium symbiosis

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Transcription Reprogramming during Root Nodule Development in Medicago truncatula

Many genes which are associated with root nodule development and activity in the model legume Medicago truncatula have been described. However information on precise stages of activation of these genes and their corresponding transcriptional regulators is often lacking. Whether these regulators are shared with other plant developmental programs also remains an open question. Here detailed microarray analyses have been used to study the transcriptome of root nodules induced by either wild type or mutant strains of Sinorhizobium meliloti. In this way we have defined eight major activation patterns in nodules and identified associated potential regulatory genes. We have shown that transcription reprogramming during consecutive stages of nodule differentiation occurs in four major phases, respectively associated with (i) early signalling events and/or bacterial infection; plant cell differentiation that is either (ii) independent or (iii) dependent on bacteroid differentiation; (iv) nitrogen fixation. Differential expression of several genes involved in cytokinin biosynthesis was observed in early symbiotic nodule zones, suggesting that cytokinin levels are actively controlled in this region. Taking advantage of databases recently developed for M. truncatula, we identified a small subset of gene expression regulators that were exclusively or predominantly expressed in nodules, whereas most other regulators were also activated under other conditions, and notably in response to abiotic or biotic stresses. We found evidence suggesting the activation of the jasmonate pathway in both wild type and mutant nodules, thus raising questions about the role of jasmonate during nodule development. Finally, quantitative RT-PCR was used to analyse the expression of a series of nodule regulator and marker genes at early symbiotic stages in roots and allowed us to distinguish several early stages of gene expression activation or repression

Characterisation of a high affinity binding site for NodRm factors in extracts of Medicago cell culture.

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Studies on the specificity of a high affinity Nod factor binding site in extracts of <em>Medicago varia</em> cell cultures.

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