Yvan Rahbe

French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Department of Plant Health and Environment

Four analogs of 3,5-dicaffeoylquinic acid, including a new heterodiester of 4-deoxyquinic acid, were found toxic against a pea aphid. Several 4-deoxy quinic analogs featuring two different hydroxyl cinnamoyl moieties in position 3 and 5 were prepared for the first time and carefully analysed. Through an assay on a pea aphid larvae, interesting indi...

The idea of applying biomimicry to cities is attracting increasing attention as a way of achieving sustainability. Undoubtedly the most frequently evoked natural model in this context is the forest, though it has not yet been investigated with any great scientific rigour. To overcome this lacuna, we provide: first, a justification of the model of t...

An amendment to this paper has been published and can be accessed via the original article.

Background: Although native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors suc...

Aphids are phloem-feeding insects known as major pests in agriculture able to transmit hundreds of plant viruses. The majority of these viruses, classified as noncirculative, are retained and transported on the inner surface of the cuticle of the needle-like mouthparts while the aphids move from plant to plant. Identification of receptors of viruse...

Insects have developed intriguing cuticles with very specific structures and functions, including microstructures governing their interactions with transmitted microbes, such as in aphid mouthparts harboring virus receptors within such microstructures. Here, we provide the first transcriptome analysis of an insect mouthpart cuticle ("retort organs"...

Insects, as small animals of frequent and easy access to humans, at least under their non-flying larval stages, have always been of interest to our species. The interest has probably been nutritional, but also naturalistic and symbolic. Many aspects of insects’ biology are of high symbolic potential, among which biodiversity, metamorphosis or fligh...

Nutritional symbioses play a central role in the ability of insects to thrive on unbalanced diets and in ensuring their evolutionary success. A genomic model for nutritional symbiosis comprises the hemipteran Acyrthosiphon pisum, and the gamma-3-proteobacterium, Buchnera aphidicola, with genomes encoding highly integrated metabolic pathways. A. pis...

PA1b (Pea Albumin 1, subunit b) peptide is an entomotoxin, extracted from Legume seeds, with a lethal activity towards several insect pests, such as mosquitoes, some aphids and cereal weevils. This toxin acts by binding to the subunits c and e of the plasma membrane H⁺-ATPase (V-ATPase) in the insect midgut. In this study, two cereal weevils, the s...

Albumin 1b peptides (A1b) are small disulfide-knotted insecticidal peptides produced by Fabaceae (also called Leguminosae). To date, their diversity among this plant family has been essentially investigated through biochemical and PCR-based approaches. The availability of high-quality genomic resources for several fabaceae species, among which the...

New dicinnamoyl (caffeoyl, feruloyl, ortho and para-coumaroyl) 4-deoxyquinic acid esters were synthesized by using a new 4-deoxy quinic acid triol intermediate. The optimisation of both coupling and deprotection steps allowed the preparation in good yields of the target products either as the carboxylic acid or the methyl ester form. Eight new comp...

In the track of new biopesticides, four genes namely cytA, cytB, cytC and cytD encoding proteins homologous to Bacillus thuringiensis (Bt) Cyt toxins have been identified in the plant pathogenic bacteria Dickeya dadantii genome. Here we show that three Cyt-like δ-endotoxins from D. dadantii (CytA, CytB and CytC) are toxic to the pathogen of the pea...

Supplementary Figure S1

Résumé. En cours de rédaction.... Ce document tapé initialement en 1998 a été le travail effectué sur une période de 1996 à 1998. Celui-ci été ré-écrit en janvier et février 2015 en raison de la perte des sources du document et dans le but de pouvoir le publier. Lors de sa ré-écriture le document à été corrigé et amélioré an d'être le plus compréhe...

RNA interference (RNAi) has been widely and successfully used for gene inactivation in insects, including aphids, where dsRNA administration can be performed either by feeding or microinjection. However, several aspects related to the aphid response to RNAi, as well as the influence of the administration method on tissue response, or the mixed succ...

The PA1b (Pea Albumin 1, subunit b) peptide is an entomotoxin extract from Legume seeds with lethal activity on several insect pests, such as mosquitoes, some aphids and cereal weevils. This 37 amino-acid cysteine-rich peptide has been, until now, obtained by biochemical purification or chemical synthesis. In this paper, we present our results for...

Florist's chrysanthemum (Chrysanthemum morifolium Ramat.) belongs to the Asteraceae family and represents the second most important floricultural crop in the world. Most genotypes are sensitive to aphids and infestations can lower quality and cause transmission of viruses. The protease inhibitor Sea Anemone Equistatin (SAE) carries three domains re...

AphidAtlas est une ressource informatique dédiée à la gestion des données anatomiques et développementales des pucerons (sur un plan d’organisation homologue des insectes). Ces informations anatomiques, morphologiques et de développement, représentées par un vocabulaire contrôlé et structuré (ontologie) sont construites pour relier les base génomiq...

Malgré leur rôle primordial dans les écosystèmes, les insectes, qui représentent les trois quarts des espèces animales identifiées, sont encore mal connus. Leur relation avec le règne végétal et l'espèce humaine, que ce soit comme compétiteurs au niveau des cultures ou comme auxiliaires, notamment par la pollinisation, revêt pourtant une importance...

Background Nutritional symbioses play a central role in insects’ adaptation to specialized diets and in their evolutionary success. The obligatory symbiosis between the pea aphid, Acyrthosiphon pisum, and the bacterium, Buchnera aphidicola, is no exception as it enables this important agricultural pest insect to develop on a diet exclusively based...

The plant pathogenic bacterium Dickeya dadantii has recently been shown to be able to kill the aphid Acyrthosiphon pisum. While the factors required to cause plant disease are now well characterized, those required for insect pathogeny remain mostly unknown. To identify these factors, we analyzed the transcriptome of the bacteria isolated from infe...

Bacterial strains used in this study. (DOC)

GSEA analysis of Gene Ontology categories in insect-infecting bacteria vs control Dickeya dadantii cells. (DOCX)

Summary of peptide LC MS analysis. (DOCX)

D. dadantii genes induced or repressed in aphid with a P value <0.002. (XLSX)

Expression of selected genes in the presence of polymyxin. (DOC)

Oligonucleotides used for RT-qPCR experiments. (DOC)

Saponins are a class of secondary plant metabolites consisting of a sugar moiety glycosidically linked to a hydrophobic aglycone (sapogenin) that often possess insecticidal activities. Four saponins were selected: two triterpene saponins, Q. saponaria saponins and aescin, and two steroidal saponins, digitonin and diosgenin. Their effects were inves...

Dickeya dadantii (syn. Erwinia chrysanthemi) is a plant pathogenic bacteria that harbours a cluster of four horizontally-transferred, insect-specific toxin genes. It was recently shown to be capable of causing an acute infection in the pea aphid Acyrthosiphon pisum (Insecta: Hemiptera). The infection route of the pathogen, and the role and in vivo...

Validation of microarray results by qRT-PCR. (A) Expression ratios of D. dadantii genes during aphid infection versus growth in liquid medium measured by qRT-PCR. Expression of each gene was normalized to the expression of the two housekeeping genes rpoA and ffh. A positive expression ratio indicates upregulated genes during aphid infection, and a...

Panels A and B: Sections of aphids infected with wild type D. dadantii and incubated with anti-Cyt63 antiserum (upper row) and with preimmune serum used as a negative control (lower row). Panel C: Sections of Cyt-defective mutants (Δcyt), incubated with anti-Cyt63 antiserum (upper row) and preimmune serum used as a negative control. Scale bar: 200...

Buchnera aphidicola is an obligate symbiotic bacterium that sustains the physiology of aphids by complementing their exclusive phloem sap diet. In this study, we reappraised the transport function of different Buchnera strains, from the aphids Acyrthosiphon pisum, Schizaphis graminum, Baizongia pistaciae and Cinara cedri, using the re-annotation of...

Essential and non-essential amino acids and derivates (Table 1), cofactors and vitamins (Table 2), input compounds (Table 3), and output compounds (Table 4) present in the BAp network and determination of the putative importers and exporters required for their biosynthesis. False positives (manually removed) from the list of the input (Table 5) and...

Schematics of transport capabilities in Buchnera from (A) Schizaphis graminum (BSg), (B) Baizongia pistaciae (BBp) and (C) Cinara cedri (BCc). Putative transporter families are presented for each class of compounds (dotted rectangles). Transporters are coloured according to their class: primary active transporters (green), secondary transporter (bl...

Ultrastructural immunogold localization of GroEL within A. pisum maternal bacteriocytes. A: low magnification view of the fields analysed for GroEL label within the bacteriocytes, showing the whole bacteriocyte with its surrounding layer of sheath cells (sc). B: control view of the immunogold labelling, with non immune rabbit serum; C-F: views of t...

Structural analysis of bacterial (Buchnera) and symbiosomal membranes in Cinara cedri (A, B) and Baizongia pistaciae (C, D), and automated procedure for membrane detection. Original pictures (upper left corner of each inlet) are filtered through FFT bandpass filter (down left corner of each inlet), regions of interest (ROI) were chosen (yellow sect...

The green peach aphid (GPA, Myzus persicae Sulzer) is a generalist insect pest infesting agricultural and horticultural crops worldwide. GPA causes significant direct damages to peach, its primary host, and may transmit viruses that cause serious diseases such as Sharka conferred by the Plum Pox Potyvirus. Resistant genotypes have been identified a...

The green peach aphid (GPA, Myzus persicae Sulzer) is a generalist insect pest infesting agricultural and horticultural crops worldwide. GPA causes significant direct damages to peach, its primary host, and may transmit viruses that cause serious diseases such as Sharka conferred by the Plum Pox Potyvirus. Resistant genotypes have been identified a...

Aphids, important agricultural pests, can grow and reproduce thanks to their intimate symbiosis with the γ-proteobacterium Buchnera aphidicola that furnishes them with essential amino acids lacking in their phloem sap diet. To study how B. aphidicola, with its reduced genome containing very few transcriptional regulators, responds to variations in...

Host plant resistance to pests is an important component of integrated control strategies. Due to the specialised phloem-feeding of aphids and many other hemipteran insect pests, which necessitates specific chemical treatments and control of virus transmission, this genetic strategy seems particularly attractive for this insect group. In the melon...

Lepidoptera, like other insects (sensu stricto, i.e., without their possible symbionts), require an exogenous input of aromatic nuclei. Phenylalanine must thus be considered as an essential amino acid; however, the most important aromatic metabolite is tyrosine. In addition to being incorporated into proteins, tyrosine goes through specific stages...

A green biotype of the pea aphid, A. pisum, from Lusignan (France), showed very poor performance on the standard Akey and Beck diet. Significant improvement occurred after reduction of the osmotic pressure of the diet and modification of the amino acid component, according to the results of carcass analysis. A further improvement was obtained throu...

In recent years, genomes from an increasing number of organisms have been sequenced, but their annotation remains a time-consuming process. The BioCyc databases offer a framework for the integrated analysis of metabolic networks. The Pathway tool software suite allows the automated construction of a database starting from an annotated genome, but i...

7-OV (ouvrages ou chapitres de vulgarisation) 2-1-3 Transfert/animation de la recherche chapitre d'ouvrage 3. Chapitres d'ouvrages En cours d'impression

The plant pathogenic bacteria Dickeya dadantii is also a pathogen of the pea aphid Acyrthosiphon pisum. The genome of the bacteria contains four cyt genes, encoding homologues of Bacillus thuringiensis Cyt toxins, which are involved in its pathogenicity to insects. We show here that these genes are transcribed as an operon, and we determined the co...

Phloem Protein2 (PP2) is a component of the phloem protein bodies found in sieve elements. We describe here the lectin properties of the Arabidopsis (Arabidopsis thaliana) PP2-A1. Using a recombinant protein produced in Escherichia coli, we demonstrated binding to N-acetylglucosamine oligomers. Glycan array screening showed that PP2-A1 also bound t...

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetab...

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetab...

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetab...

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetab...

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetab...

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