Nathalie Frangne
Institut national de la recherche agronomique
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Featured researches published by Nathalie Frangne.
Plant Physiology | 2005
Catherine Cheniclet; Wen Ying Rong; Mathilde Causse; Nathalie Frangne; Laurence Bolling; Jean-Pierre Carde; Jean-Pierre Renaudin
Postanthesis growth of tomato (Solanum lycopersicon) as of many types of fruit relies on cell division and cell expansion, so that some of the largest cells to be found in plants occur in fleshy fruit. Endoreduplication is known to occur in such materials, which suggests its involvement in cell expansion, although no data have demonstrated this hypothesis as yet. We have analyzed pattern formation, cell size, and ploidy in tomato fruit pericarp. A first set of data was collected in one cherry tomato line throughout fruit development. A second set of data was obtained from 20 tomato lines displaying a large weight range in fruit, which were compared as ovaries at anthesis and as fully grown fruit at breaker stage. A remarkable conservation of pericarp pattern, including cell layer number and cell size, is observed in all of the 20 tomato lines at anthesis, whereas large variations of growth occur afterward. A strong, positive correlation, combining development and genetic diversity, is demonstrated between mean cell size and ploidy, which holds for mean cell diameters from 10 to 350 μm (i.e. a 32,000-times volume variation) and for mean ploidy levels from 3 to 80 C. Fruit weight appears also significantly correlated with cell size and ploidy. These data provide a framework of pericarp patterning and growth. They strongly suggest the quantitative importance of polyploidy-associated cell expansion as a determinant of fruit weight in tomato.
Plant Physiology | 1997
Pierrette Fleurat-Lessard; Nathalie Frangne; Masayoshi Maeshima; Raphael Ratajczak; Jean-Louis Bonnemain; Enrico Martinoia
Mature motor cells of Mimosa pudica that exhibit large and rapid turgor variations in response to external stimuli are characterized by two distinct types of vacuoles, one containing large amounts of tannins (tannin vacuole) and one without tannins (colloidal or aqueous vacuole). In these highly specialized cells we measured the abundance of two tonoplast proteins, a putative water-channel protein (aquaporin belonging to the [gamma]-TIPs [tonoplast intrinsic proteins]) and the catalytic A-subunit of H+-ATPase, using either high-pressure freezing or chemical fixation and immunolocalization. [gamma]-TIP aquaporin was detected almost exclusively in the tonoplast of the colloidal vacuole, and the H+-ATPase was also mainly localized in the membrane of the same vacuole. Cortex cells of young pulvini cannot change shape rapidly. Development of the pulvinus into a motor organ was accompanied by a more than 3-fold increase per length unit of membrane in the abundance of both aquaporin and H+-ATPase cross-reacting protein. These results indicate that facilitated water fluxes across the vacuolar membrane and energization of the vacuole play a central role in these motor cells.
Plant Physiology | 2002
Nathalie Frangne; Thomas Eggmann; Carsten Koblischke; Gottfried Weissenböck; Enrico Martinoia; Markus Klein
In many cases, secondary plant products accumulate in the large central vacuole of plant cells. However, the mechanisms involved in the transport of secondary compounds are only poorly understood. Here, we demonstrate that the transport mechanisms for the major barley (Hordeum vulgare) flavonoid saponarin (apigenin 6-C-glucosyl-7-O-glucoside) are different in various plant species: Uptake into barley vacuoles occurs via a proton antiport and is competitively inhibited by isovitexin (apigenin 6-C-glucoside), suggesting that both flavone glucosides are recognized by the same transporter. In contrast, the transport into vacuoles from Arabidopsis, which does not synthesize flavone glucosides, displays typical characteristics of ATP-binding cassette transporters. Transport of saponarin into vacuoles of both the species is saturable with a K m of 50 to 100 μm. Furthermore, the uptake of saponarin into vacuoles from a barley mutant exhibiting a strongly reduced flavone glucoside biosynthesis is drastically decreased when compared with the parent variety. Thus, the barley vacuolar flavone glucoside/H+antiporter could be modulated by the availability of the substrate. We propose that different vacuolar transporters may be responsible for the sequestration of species-specific/endogenous and nonspecific/xenobiotic secondary compounds in planta.
Annals of Botany | 2011
Christian Chevalier; Mehdi Nafati; Elodie Mathieu-Rivet; Matthieu Bourdon; Nathalie Frangne; Catherine Cheniclet; Jean-Pierre Renaudin; Frédéric Gévaudant; Michel Hernould
BACKGROUNDnEndoreduplication is the major source of endopolyploidy in higher plants. The process of endoreduplication results from the ability of cells to modify their classical cell cycle into a partial cell cycle where DNA synthesis occurs independently from mitosis. Despite the ubiquitous occurrence of the phenomenon in eukaryotic cells, the physiological meaning of endoreduplication remains vague, although several roles during plant development have been proposed, mostly related to cell differentiation and cell size determination.nnnSCOPEnHere recent advances in the knowledge of endoreduplication and fruit organogenesis are reviewed, focusing on tomato (Solanum lycopersicum) as a model, and the functional analyses of endoreduplication-associated regulatory genes in tomato fruit are described.nnnCONCLUSIONSnThe cyclin-dependent kinase inhibitory kinase WEE1 and the anaphase promoting complex activator CCS52A both participate in the control of cell size and the endoreduplication process driving cell expansion during early fruit development in tomato. Moreover the fruit-specific functional analysis of the tomato CDK inhibitor KRP1 reveals that cell size and fruit size determination can be uncoupled from DNA ploidy levels, indicating that endoreduplication acts rather as a limiting factor for cell growth. The overall functional data contribute to unravelling the physiological role of endoreduplication in growth induction of fleshy fruits.
New Phytologist | 2010
Mehdi Nafati; Nathalie Frangne; Michel Hernould; Christian Chevalier; Frédéric Gévaudant
• Cyclin-dependent kinase (CDK) inhibitors (kip-related proteins, KRPs) play a major role in the regulation of plant cell cycle in antagonizing its progression, and are thus regulators of development. The primary sequence of KRPs is characterized by the existence of conserved motifs, for which we have limited information on their functional significance. • We performed a functional analysis of various domains present in KRPs from tomato. A series of deletion mutants of SlKRP1 was generated and used in transient expression assays to define the relevance of conserved protein domains in subcellular and subnuclear localizations. Specific interactions of SlKRP1 and its deletion variants with cell cycle proteins were investigated using two-hybrid assays and bimolecular fluorescent complementation. • Plant KRPs are distributed into two phylogenetic subgroups according to the presence of conserved motifs. Members of subgroup 1 represented by SlKRP1 share 6 conserved motifs whose function in protein localization and protein-protein interactions could be identified. A new interaction motif was localized in the central part of SlKRP1 that targets SlCDKA1 and SlCYCD3;1 to the nucleus. • Our results bring new insights to the functional role of particular domains in KRPs relative to subcellular localization or proteolytic degradation.
FEBS Letters | 2003
Cyrille Forestier; Nathalie Frangne; Thomas Eggmann; Markus Klein
The role of ATP‐binding cassette (ABC) proteins such as multidrug resistance‐associated proteins (MRPs) is critical in drug resistance in cancer cells and in plant detoxification processes. Due to broad substrate spectra, specific modulators of these proteins are still lacking. Sulfonylureas such as glibenclamide are used to treat non‐insulin‐dependent diabetes since they bind to the sulfonylurea receptor. Glibenclamide also inhibits the cystic fibrosis transmembrane conductance regulator, p‐glycoprotein in animals and guard cell ion channels in plants. To investigate whether this compound is a more general blocker of ABC transporters the sensitivity of ABC‐type transport processes across the vacuolar membrane of plants and yeast towards glibenclamide was evaluated. Glibenclamide inhibits the ATP‐dependent uptake of β‐estradiol 17‐(β‐D‐glucuronide), lucifer yellow CH, and (2′,7′‐bis‐(2‐carboxyethyl)‐5‐(and‐6‐)carboxyfluorescein. Transport of glutathione conjugates into plant but not into yeast vacuoles was drastically reduced by glibenclamide. Thus, irrespective of the homologies between plant, yeast and animal MRP transporters, specific features of plant vacuolar MRPs with regard to sensitivity towards sulfonylureas exist. Glibenclamide could be a useful tool to trap anionic fluorescent indicator dyes in the cytosol.
Journal of Experimental Botany | 2017
Jean-Pierre Renaudin; Cynthia Deluche; Catherine Cheniclet; Christian Chevalier; Nathalie Frangne
Highlight Cell expansion and cell division resume simultaneously at fruit set in specific cell layers of the tomato pericarp, and display complementary quantitative importance during fruit growth.
Plant Journal | 2018
Julien Pirrello; Cynthia Deluche; Nathalie Frangne; Frédéric Gévaudant; Elie Maza; Anis Djari; Mickael Bourge; Jean-Pierre Renaudin; Spencer C. Brown; Chris Bowler; Mohamed Zouine; Christian Chevalier; Nathalie Gonzalez
As part of normal development most eukaryotic organisms, ranging from insects and mammals to plants, display variations in nuclear ploidy levels resulting from somatic endopolyploidy. Endoreduplication is the major source of endopolyploidy in higher plants. Endoreduplication is a remarkable characteristic of the fleshy pericarp tissue of developing tomato fruits, where it establishes a highly integrated cellular system that acts as a morphogenetic factor supporting cell growth. However, the functional significance of endoreduplication is not fully understood. Although endoreduplication is thought to increase metabolic activity due to a global increase in transcription, the issue of gene-specific ploidy-regulated transcription remains open. To investigate the influence of endoreduplication on transcription in tomato fruit, we tested the feasibility of a RNA sequencing (RNA-Seq) approach using total nuclear RNA extracted from purified populations of flow cytometry-sorted nuclei based on their DNA content. Here we show that cell-based approaches to the study of RNA-Seq profiles need to take into account the putative global shift in expression between samples for correct analysis and interpretation of the data. From ploidy-specific expression profiles we found that the activity of cells inside the pericarp is related both to the ploidy level and their tissue location.
Molecular Biology of the Cell | 2003
Markus Geisler; H. Üner Kolukisaoglu; Rodolphe Bouchard; Karla Billion; Joachim Berger; Beate Saal; Nathalie Frangne; Zsuzsanna Koncz-Kálmán; Csaba Koncz; Robert Dudler; Joshua J. Blakeslee; Angus S. Murphy; Enrico Martinoia; Burkhard Schulz
Plant Physiology | 2000
Markus Geisler; Nathalie Frangne; Eric Gomès; Enrico Martinoia; Michael G. Palmgren