The Date Palm (Phoenix dactylifera L.) leaf proteome: identification of a gender biomarker to screen male parents

Abstract To establish a proteomic reference map of date palm leaves (Deglet Nour cultivar), we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, respectively. In total, 284 spots were excised from gel and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Among them, 158 were successfully identified (i.e, a success rate of 55.6%) conducting to the identification of 126 unique proteins. These proteins were then clustered according to their functional annotations. Identified proteins were involved in metabolism, electron transport, photosynthesis, protein synthesis, cell structure or defence. However, 29.4 % of the identifications gave unknown function. We then compared the proteome map of female and male trees. Only one discriminated spot was found to be specific of the gender. We identified the corresponding protein as an ABC superfamily ATP binding cassette transporter, ABC protein, a protein whose an ortholog in Arabidopsis thaliana was already reported as required for male fertility and pollen formation. The relevance of this protein as gender biomarker was then confirmed in four other cultivars, i.e., Aligue, Khouet Aligue, Kentichi and Kenta. Such biomarker should be helpful in rapidly distinguishing date palm gender of immature trees

N-glycosidase treatment with 18O labeling and de novo sequencing argues for flagellin FliC glycopolymorphism in Pseudomonas aeruginosa.

International audienceIn prokaryote organisms, N-glycosylation of proteins is often correlated to cell-cell recognition and extracellular events. Those glycoproteins are potential targets for infection control. To date, many surface-glycosylated proteins from bacterial pathogens have been described. However, N-linked Pseudomonas surface-associated glycoproteins remain underexplored. We report a combined enrichment and labeling strategy to identify major glycoproteins on the outside of microorganisms. More precisely, bacteria were exposed to a mix of biotinylated lectins able to bind with glycoproteins. The latter were then recovered by avidin beads, digested with trypsin, and submitted to mass spectrometry. The targeted mixture of glycoproteins was additionally deglycosylated in the presence of H2(18)O to incorporate (18)O during PNGase F treatment and were also analyzed using mass spectrometry. This approach allowed us to identify a few tens of potential N-glycoproteins, among which flagellin FliC was the most abundant. To detect the possible sites of FliC modifications, a de novo sequencing step was also performed to discriminate between spontaneous deamidation and N-glycan loss. This approach led to the proposal of three potential N-glycosylated sites on the primary sequence of FliC: N26, N69, and N439, with two of these three asparagines belonging to an N-X-(S/T) consensus sequence. These observations suggest that flagellin FliC is a heterogeneous protein mixture containing both O- and N-glycoforms

Étude différentielle des protéomes de branchies de dreissènes (moules d’eau douce) récoltées sur des sites pollués ou non

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Outer-membrane proteomic maps and surface-exposed proteins of Legionella pneumophila using cellular fractionation and fluorescent labelling

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Deciphering the Molecular Diversity of an Ant Venom Peptidome through a Venomics Approach

International audienceThe peptide toxins in the venoms of small invertebrates such as stinging ants have rarely been studied due to the limited amount of venom available per individual. We used a venomics strategy to identify the molecular diversity of the venom peptidome for the myrmicine ant Tetramorium bicarinatum. The methodology included (i) peptidomics, in which the venom peptides are sequenced through a de novo mass spectrometry approach or Edman degradation; (ii) transcriptomics, based on RT-PCR-cloning and DNA sequencing; and (iii) the data mining of the RNA-seq in the available transcriptome. Mass spectrometry analysis revealed about 2800 peptides in the venom. However, the de novo sequencing suggested that most of these peptides arose from processing or the artifactual fragmentations of full-length mature peptides. These peptides, called "myrmicitoxins", are produced by a limited number of genes. Thirty-seven peptide precursors were identified and classified into three superfamilies. These precursors are related to pilosulin, secapin or are new ant venom prepro-peptides. The mature myrmicitoxins display sequence homologies with antimicrobial, cytolytic and neurotoxic peptides. The venomics strategy enabled several post-translational modifications in some peptides such as O-glycosylation to be identified. This study provides novel insights into the molecular diversity and evolution of ant venoms

Biofilm-induced modifications in the proteome of Pseudomonas aeruginosa planktonic cells

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Structural characterization of the dolichol linked precursor in the green microalgae, Chlamydomonas reinhardtii

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Structural characterization of the dolichol linked precursor in the green microalgae, Chlamydomonas reinhardtii

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Exploring the subcellular localization of xylosylated N-glycoproteins in Chlamydomonas reinhardtii

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