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Marie-Laure Fauconnier

Publications and source records attributed to Marie-Laure Fauconnier.

7 recordsLinked to original sources
PubMed2025

Comparative analysis of DREB gene family in buckwheat: the role of FtDREB02 in the delphinidin biosynthesis and drought stress response.

Dehydration response element binding (DREB) transcription factors play a pivotal role in plant abiotic stress responses, but its evolutionary and functional characterization in buckwheat remains unexplored. Here, we conducted a comprehensive analysis of the DREB gene family across three buckwheat species, revealing segmental duplication as the primary driver of family expansion and potential purifying selection during evolution. A FtDREB02 gene, classified as group A2, was identified through genome-wide association analysis (GWAS) on drought tolerance and delphinidin content. Functional validation in Arabidopsis thaliana and the hairy root of Tartary buckwheat (Fagopyrum tataricum) demonstrated that overexpression of this gene promotes delphinidin biosynthesis and enhances plant resistance to water scarcity. Through the integration of DAP-seq and PEG transcriptome cluster analysis, a FtANS candidate was screened. Functional studies showed that FtDREB02 regulates delphinidin content by binding directly to DRE elements of the FtANS promoter. This research identifies and comprehensively analyzes the DREB family within buckwheat species, elucidating the regulatory mechanisms of FtDREB02 in controlling flavonoid biosynthesis and drought resistance, providing potential genetic resources for breeding buckwheat varieties with excellent agronomic traits.

Anthocyanins↗
PubMed2006

Study of precursors responsible for off-flavor formation during storage of potato flakes.

Off-flavors frequently appear during the storage of potato flakes. Volatile profile analysis performed by solid-phase microextraction-gas chromatography-mass spectrometry revealed that hexanal is the main compound that appears during the storage period. Hexanal may be a degradation product of linoleic acid formed through linoleic acid hydroperoxide cleavage. Profiles of hexanal precursors were determined from potato flakes at different storage time points. Linoleic acid-derived oxylipins are predominant in potato flakes. The free oxylipins identified, in descending order, are as follows: hexanal, hydroxy polyunsaturated fatty (PUFAs), oxo PUFAs, divinyl ether PUFAs, and hydroperoxy PUFAs. However, the main oxylipins detected were esterified: esterified hydroxy, hydroperoxy, and oxo PUFAs. Oxylipins reveal different evolutions during the storage period. Chiral high-performance liquid chromatography analysis of the precursors of hexanal and other oxylipins revealed a racemic composition that supports the nonenzymatic formation of hexanal and most of the other oxylipins identified.

Aldehydes↗
PubMed2006

Potato tuber proteomics: comparison of two complementary extraction methods designed for 2-DE of acidic proteins.

Two protein extraction procedures were tested in order to remove interfering compounds prior to 2-DE of potato tubers. These methods using SDS lysis buffer and phenol-phase extraction were compared regarding the quality of the resulting 2-D gel. While the resolution of SDS extracts on semipreparative gels seems better, both methods lead to similar extraction yields and total number of spots. The procedures are complementary regarding the Mr range of preferentially extracted proteins.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2004

Stimulation of the lipoxygenase pathway is associated with systemic resistance induced in bean by a nonpathogenic Pseudomonas strain.

Systemic defense reactions induced in bean by the non-pathogenic Pseudomonas putida BTP1 strain reduced disease caused by Botrytis cinerea. Phenylalanine ammonialyase activity and the level of endogenous free salicylic acid were compared in plant growth-promoting rhizobacteria-treated versus control plants, but no significant differences were detected. Furthermore, no enhanced fungitoxicity was detected in methanolic leaf extracts, suggesting that accumulation of bean phytoalexins was not part of the stimulated defense mechanisms. However, BTP1-inoculated plants showed increased levels of both linoleic and linolenic acids. On this basis, we further investigated whether the lipoxygenase pathway, leading to antifungal phytooxylipins, could have been stimulated. Two key enzymatic activities of this metabolic route, namely lipoxygenase and hydroperoxide lyase, were significantly stimulated during the first four days after challenging BTP1-treated plants with the pathogen. This was observed in parallel with a more rapid consumption of the respective substrates of these enzymes, as revealed by measurements of endogenous concentrations of linolenic acid and their hydroperoxide derivatives. Moreover, headspace-gas chromatography analyses showed significantly higher concentrations of the fungitoxic final product Z-3-hexenal in leaves from BTP1-inoculated beans as compared with control plants. Taken together, these results strongly suggest that the oxylipin pathway can be associated with enhanced disease resistance induced in bean plants by nonpathogenic rhizobacteria.

Botrytis↗
PubMed2003

Potato tuber phospholipids contain colneleic acid in the 2-position.

Colneleic acid (9-[1'(E),3'(Z)-nonadienyloxy]-8(E)-nonenoic acid) is produced from linoleic acid by the sequential action of 9-lipoxygenase and divinyl ether synthase. We demonstrate that a small fraction of the colneleic acid in potato tubers is esterified in phospholipids. This colneleic acid was released by chemical hydrolysis and a phospholipase A(2), but not by a lipase with 1-acyl specificity. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol contain molecular species with nominal masses consistent with identification as palmitoyl,colneleoyl species. Exact mass analysis of its fragments confirmed the identity of palmitoyl,colneloyl phosphatidylinositol. To our knowledge, this work represents the first identification of a colneleoyl phospholipid.

Chromatography, High Pressure Liquid↗
PubMed2003

Formation of plant cuticle: evidence for the occurrence of the peroxygenase pathway.

Cuticle plays a major role as a protective barrier in plants. Despite its physiological importance, the mode of formation of this complex structure remains poorly understood. In particular, none of the putative enzymes involved in the biosynthesis of the cutin, the matrix of cuticle, have been cloned. We have shown previously that peroxygenase is able to catalyze in vitro the epoxidation step required for the biosynthesis of C18 cutin monomers. In the present work, we have confirmed in planta that this oxidase is indeed a key enzyme involved in the formation of cutin. Thus, in maize leaves, the specific inactivation of peroxygenase by organophosphorothioates resulted in a dramatic decrease of cuticular epoxide content, as visualized by a specific histochemical technique that was accompanied by a reduced thickness of the cuticle. A strict correlation could also be established between the extent of inhibition of the peroxygenase and the modification of the cuticle triggered by a family of structurally related inhibitors. Importantly, these effects were restricted to plants that contain a cutin originating from C18 monomers. The altered cuticle of maize, treated with the peroxygenase inhibitor, was characterized by an increased permeability to pesticides. In addition, such plants became largely susceptible to infection by fungi, implying that the cuticle represents a crucial target for the modulation of the response in plant-pathogen interactions.

Herbicides↗