Pascal Gamas

Pascal Gamas
French National Centre for Scientific Research | CNRS · Laboratoire des Interactions Plantes Microbes Environnement (LIPME) CNRS-INRA

PhD

About

145
Publications
17,011
Reads
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5,354
Citations
Citations since 2016
40 Research Items
2629 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Additional affiliations
January 1991 - present
French National Centre for Scientific Research
Position
  • Group Leader
Education
September 1983 - November 1986
University of Toulouse
Field of study
  • Microbiology

Publications

Publications (145)
Article
Symbiotic nitrogen fixation (SNF) can play a key role in agro-eco systems to reduce the negative impact of nitrogen fertilizers. Its efficiency is strongly affected by the combination of bacterial and plant genotypes, but the mechanisms responsible for the differences in efficiency of rhizobium strains are not well documented. In Medicago truncatul...
Article
Full-text available
Plant epigenetic regulations are involved in transposable element silencing, developmental processes and responses to the environment1–7. They often involve modifications of DNA methylation, particularly through the DEMETER (DME) demethylase family and RNA-dependent DNA methylation (RdDM)8. Root nodules host rhizobia that can fix atmospheric nitrog...
Article
Rhizobium-legume nitrogen-fixing symbiosis involves the formation of a specific organ, the root nodule, which provides bacteria with the proper cellular environment for atmospheric nitrogen fixation. Coordinated differentiation of plant and bacterial cells is an essential step of nodule development, for which few transcriptional regulators have bee...
Article
Full-text available
Nodulation regulation Legumes convert atmospheric nitrogen into biologically useful ammonium with the help of symbiotic bacteria housed in root nodules. Much of nodule development is controlled by the transcription factor NODULE INCEPTION (NIN). Feng et al . show that NIN is proteolytically processed to release a fragment that regulates the later s...
Article
Although RNA sequencing has been becoming the main transcriptomic approach in the model legume Medicago truncatula, there is currently no genome-wide gene expression atlas covering the whole set of RNAseq data published for this species. Nowadays, such tool is highly valuable to provide a global view of gene expression in a wide range of conditions...
Preprint
Full-text available
Although RNA sequencing has been becoming the main transcriptomic approach in the model legume Medicago truncatula , there is currently no genome-wide gene expression atlas covering the whole set of RNAseq data published for this species. Nowadays, such tool is highly valuable to provide a global view of gene expression in a wide range of condition...
Article
Medicago truncatula was proposed, about three decades ago, as a model legume to study the Rhizobium-legume symbiosis. It has now been adopted to study a wide range of biological questions, including various developmental processes (in particular root, symbiotic nodule and seed development), symbiotic (nitrogen-fixing and arbuscular mycorrhizal endo...
Article
Full-text available
Background Legumes can establish on nitrogen-deprived soils a symbiotic interaction with Rhizobia bacteria, leading to the formation of nitrogen-fixing root nodules. Cytokinin phytohormones are critical for triggering root cortical cell divisions at the onset of nodule initiation. Cytokinin signaling is based on a Two-Component System (TCS) phospho...
Article
Full-text available
Advances in deciphering the functional architecture of eukaryotic genomes have been facilitated by recent breakthroughs in sequencing technologies, enabling a more comprehensive representation of genes and repeat elements in genome sequence assemblies, as well as more sensitive and tissue-specific analyses of gene expression. Here we show that PacB...
Chapter
Understanding the development of multicellular organisms requires the identification of regulators, notably transcription factors, and specific transcript populations associated with tissue differentiation. Laser capture microdissection (LCM) is one of the techniques that enable the analysis of distinct tissues or cells within an organ. Coupling th...
Article
Substantial progress has been made in the understanding of early stages of the symbiotic interaction between legume plants and rhizobium bacteria. Those include the specific recognition of symbiotic partners, the initiation of bacterial infection in root hair cells, and the inception of a specific organ in the root cortex, the nodule. Increasingly...
Article
Legumes associate with rhizobia to form nitrogen (N2)-fixing nodules, which is important for plant fitness [1, 2]. Medicago truncatula controls the terminal differentiation of Sinorhizobium meliloti into N2-fixing bacteroids by producing defensin-like nodule-specific cysteine-rich peptides (NCRs) [3, 4]. The redox state of NCRs influences some biol...
Article
Full-text available
The legume-Rhizobium symbiosis leads to the formation of a new organ, the root nodule, involving coordinated and massive induction of specific genes. Several genes controlling DNA methylation are spatially regulated within the Medicago truncatula nodule, notably the demethylase gene, DEMETER (DME), which is mostly expressed in the differentiation z...
Article
Legume plants adapt to low nitrogen by developing an endosymbiosis with nitrogen-fixing soil bacteria to form a new specific organ: the nitrogen-fixing nodule. In the Medicago truncatula model legume, the MtCRE1 cytokinin receptor is essential for this symbiotic interaction. As three other putative CHASE Histidine Kinase (CHK) cytokinin receptors e...
Article
Full-text available
Nod factors (NF) are lipochitooligosaccharidic signal molecules produced by rhizobia, which play a key role in the rhizobium-legume symbiotic interaction. In this study, we analyzed the gene expression reprogramming induced by purified NF (4h and 24h of treatment) in the root epidermis of the model legume Medicago truncatula. Tissue-specific transc...
Article
Legume plants adapt to low nitrogen by developing an endosymbiosis with nitrogen-fixing soil bacteria to form a new specific organ: the nitrogen-fixing nodule. In the Medicago truncatula model legume, the MtCRE1 cytokinin receptor is essential for this symbiotic interaction. As three other putative CHASE-domain containing histidine kinase (CHK) cyt...
Article
Full-text available
The endosymbiotic association between legumes and soil bacteria called rhizobia leads to the formation of a new root-derived organ called the nodule in which differentiated bacteria convert atmospheric nitrogen into a form that can be assimilated by the host plant. Successful root infection by rhizobia and nodule organogenesis require the activatio...
Article
Next-generation sequencing technologies allow an almost exhaustive survey of the transcriptome even in species with no available genome sequence. To produce a Unigene set representing most of the expressed genes of pea, 20 cDNA libraries produced from various plant tissues harvested at different developmental stages on plants grown in contrasted N-...
Chapter
Legumes are able to establish symbioses with nitrogen-fixing soil bacteria called rhizobia, which enable them to grow in nitrogen-poor soil. This symbiosis involves a complex interplay between host and bacterial partners, resulting in the formation of a novel organ, the root nodule, within which the microbial symbiont is accommodated and fixes nitr...
Article
Myc-LCOs are newly identified symbiotic signals produced by arbuscular mycorrhizal (AM) fungi. Like rhizobial Nod factors, they are lipo-chitooligosaccharides that activate the common symbiotic signalling pathway (CSSP) in plants. To increase our limited understanding of the roles of Myc-LCOs we aimed to analyse Myc-LCO-induced transcriptional chan...
Article
During endosymbiotic interactions between legume plants and nitrogen-fixing rhizobia, successful root infection by bacteria and nodule organogenesis requires the perception and transduction of bacterial lipo-chitooligosaccharidic signal called Nod Factor (NF). NF perception in legume roots leads to the activation of an early signaling pathway and o...
Article
Full-text available
Rhizobium-induced root nodules are organs specialized for symbiotic nitrogen fixation. Indeterminate-type nodules are formed from an apical meristem and exhibit a spatial zonation which corresponds to successive developmental stages. To get a dynamic and integrated view of plant and bacterial gene expression associated with nodule development, we s...
Article
Full-text available
A plant-microbe dual biological system was set up involving the model legume Medicago truncatula and two bacteria, the soil-borne root pathogen Ralstonia solanacearum and the beneficial symbiont Sinorhizobium meliloti. Comparison of transcriptomes under symbiotic and pathogenic conditions highlighted the transcription factor MtEFD (Ethylene respons...
Article
Full-text available
Symbiosis between legume plants and soil rhizobia culminates in the formation of a novel root organ, the ‘nodule’, containing bacteria differentiated as facultative nitrogen-fixing organelles. MtNF-YA1 is a Medicago truncatula CCAAT box-binding transcription factor (TF), formerly called HAP2-1, highly expressed in mature nodules and required for no...
Article
Full-text available
In seeds, desiccation tolerance (DT) and the ability to survive the dry state for prolonged periods of time (longevity) are two essential traits for seed quality that are consecutively acquired during maturation. Using transcriptomic and metabolomic profiling together with a conditional-dependent network of global transcription interactions, we dis...
Article
Full-text available
The availability of next-generation sequences of transcripts from prokaryotic organisms offers the opportunity to design a new generation of automated genome annotation tools not yet available for prokaryotes. In this work, we designed EuGene-P, the first integrative prokaryotic gene finder tool which combines a variety of high-throughput data, inc...
Article
Transcription 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 fo...
Article
Full-text available
This study aimed at defining the role of a basic helix–loop–helix (bHLH) transcription factor gene from Medicago truncatula, MtbHLH1, whose expression is upregulated during the development of root nodules produced upon infection by rhizobia bacteria. We used MtbHLH1 promoter::GUS fusions and quantitative reverse-transcription polymerase chain reac...
Data
Cross comparison of differentially regulated genes found in different nodule samples compared to non-inoculated roots. (XLS)
Data
Search of co-regulated transcription factors using the Medicago truncatula gene atlas data. (XLS)
Data
List of primers used for quantitative RT-PCR analyses. (DOC)
Data
list of 16kPlus reporters scored as differentially regulated in nodules, as compared to non inoculated, nitrogen-starved roots. (XLS)
Data
List of genes classified by MapMan as related to heme (hemoglobin genes), phenylpropanoids and flavonoids. (XLS)
Data
Example of a WRKY transcription factor gene from the exo1 regulation class activated both in nodules and pathogenic conditions. Gene up-regulated in wild type and mutant nodules ([19][20], this study) as well as M. truncatula plants treated by yeast elicitor [68] or challenged with the bacterial pathogen Pseudomonas syringae [103]. (TIFF)
Data
Use of the Legoo knowledge base to search for possible expression of nodule-associated regulators in other conditions. (XLS)
Data
Examples of multigene families containing root-expressed genes and nodule-associated genes. (XLS)
Data
list of putative regulator genes scored as differentially regulated in nodules when compared to non inoculated, nitrogen-starved roots. (XLS)
Data
Quantitative RT-PCR analyses in root samples. (XLS)