Activité biologique de la sève phloémique du palmier datier Phoenix dactylifera L.
; Francis, Frédéric ; Blecker, Christophe et al
Poster (2006)Detailed reference viewed: 21 (5 ULg)
Characterization and tissue-specific expression of two lepidopteran farnesyl diphosphate synthase homologs: Implications for the biosynthesis of ethyl-substituted juvenile hormones
; ; et al
in Proteins-Structure Function and Bioinformatics (2006), 65(3), 742758
The sesquiterpenoid juvenile hormone (JH) regulates insect development and reproduction. Most insects produce only one chemical form of JH, but the Lepidoptera produce four derivatives featuring ethyl ... [more ▼]
The sesquiterpenoid juvenile hormone (JH) regulates insect development and reproduction. Most insects produce only one chemical form of JH, but the Lepidoptera produce four derivatives featuring ethyl branches. The biogenesis of these JHs requires the synthesis of ethyl-substituted farnesyl diphosphate (FPP) by FPP synthase (FPPS). To determine if there exist more than one lepidopteran FPPS, and whether one FPPS homolog is better adapted for binding the builder ethyl-branched substrates/products, we cloned three lepidopteran FPPS cDNAs, two from Choristoneura fumiferana and one from Pseudaletia unipuncta. Amino acid sequence comparisons among these and other eukaryotic FPPSs led to the recognition of two lepidopteran FPPS types. Type-I FPPSs display unique active site substitutions, including several in and near the first aspartaterich motif, whereas type-II proteins have a more "conventional" catalytic cavity. In a yeast assay, a Drosophila FPPS clone provided full complementation of an FPPS mutation, but lepidopteran FPPS clones of either type yielded only partial complementation, suggesting unusual catalytic features and/or requirements of these enzymes. Although a structural analysis of lepidopteran FPPS active sites suggested that type-I enzymes are better suited than type-II for generating ethyl-substituted products, a quantitative real-time PCR assessment of their relative abundance in insect tissues indicated that type-I expression is ubiquitous whereas that of type-II is essentially confined to the JH-producing glands, where its transcripts are ∼20 times more abundant than those of type-I. These results suggest that type-II FPPS plays a leading role in lepidopteran JH biosynthesis in spite of its apparently more conventional catalytic cavity [less ▲]Detailed reference viewed: 20 (4 ULg)
Aphids (Myzus persicae) lipoxygenase and oxylipins profiling.
; ; et al
Conference (2006)Detailed reference viewed: 10 (2 ULg)
Proteome variations of the Myzus persicae aphid according to host plant change.
Francis, Frédéric ; ; Harmel, Nicolas et al
in Insect Biochemistry and Molecular Biology (2006), 36(3), 219-227Detailed reference viewed: 35 (9 ULg)
Proteomics in Myzus persicae: effect of aphid host plant switch.
Francis, Frédéric ; ; Harmel, Nicolas et al
in Insect Biochemistry and Molecular Biology (2006), 36(3), 219-27
Chemical ecology is the study of how particular chemicals are involved in interactions of organisms with each other and with their surroundings. In order to reduce insect attack, plants have evolved a ... [more ▼]
Chemical ecology is the study of how particular chemicals are involved in interactions of organisms with each other and with their surroundings. In order to reduce insect attack, plants have evolved a variety of defence mechanisms, both constitutive and inducible, while insects have evolved strategies to overcome these plant defences (such as detoxification enzymes). A major determinant of the influence of evolutionary arms races is the strategy of the insect: generalist insect herbivores, such as Myzus persicae aphid, need more complex adaptive mechanisms since they need to respond to a large array of different plant defensive chemicals. Here we studied the chemical ecology of M. persicae associated with different plant species, from Brassicaceae and Solanaceae families. To identify the involved adaptation systems to cope with the plant secondary substances and to assess the differential expression of these systems, a proteomic approach was developed. A non-restrictive approach was developed to identify all the potential adaptation systems toward the secondary metabolites from host plants. The complex protein mixtures were separated by two-dimensional electrophoresis methods and the related spots of proteins significantly varying were selected and identified by mass spectrometry (ESI MS/MS) coupled with data bank investigations. Fourteen aphid proteins were found to vary according to host plant switch; ten of them were down regulated (proteins involved in glycolysis, TCA cycle, protein and lipid synthesis) while four others were overexpressed (mainly related to the cytoskeleton). These techniques are very reliable to describe the proteome from organisms such as insects in response to particular environmental change such as host plant species of herbivores. [less ▲]Detailed reference viewed: 62 (8 ULg)
Evaluation des facteurs de risque liés au dépérissement des abeilles domestiques en Région wallonne et leur implication sur les bonnes pratiques agricoles.
Nguyen, Bach Kim ; Widart, Joëlle ; Thomé, Jean-Pierre et al
Report (2006)Detailed reference viewed: 35 (8 ULg)
Calcul d’indicateurs de risque liés à l’utilisation de produits phytosanitaires : calcul de risque (type PRIBEL) pour les abeilles, agrégation et cartographie pour la Région wallonne.
; Nguyen, Bach Kim ; et al
Report (2006)Detailed reference viewed: 53 (9 ULg)
Valorization of biocide molecules within the pea seed (Pisum sativum L.) industrial residues.
; Haubruge, Eric ; Francis, Frédéric
in Communications in Agricultural and Applied Biological Sciences (2006), 71(2 Pt A), 115-20Detailed reference viewed: 32 (5 ULg)
Le dépérissement de l'abeille domestique, Apis mellifera L., 1758 ( Hymenoptera : Apidae) : faits et causes probables.
Haubruge, Eric ; Nguyen, Bach Kim ; Widart, Joëlle et al
in Notes Fauniques de Gembloux (2006), 59(1), 3-21Detailed reference viewed: 225 (26 ULg)
Inter- and intra-guild interactions related to aphids in nettle (Urtica dioica L.) strips closed to field crops.
; Haubruge, Eric ; Bodson, Bernard et al
in Communications in Agricultural and Applied Biological Sciences (2006), 71(2 Pt B), 413-23
A field experiment designed to assess the biodiversity related to nettle strips closed to crops, and more particularly the aphid and related beneficial populations, was established in experimental farm ... [more ▼]
A field experiment designed to assess the biodiversity related to nettle strips closed to crops, and more particularly the aphid and related beneficial populations, was established in experimental farm located in Gembloux (Belgium). Margin strips of nettle (Urtica dioica) closed to wheat (Triticum aestivum), green pea (Pisum sativum) and rape (Brassicae napus) fields were investigated. The diversity, abundance of aphids and related predators were analysed according to the plant crop species and the differential pesticide application (treated plot and control). Insects were visually observed every week during all the cultivation season. Two main families of aphidophagous predators were found in all field crops and nettle, the Coccinellidae and Syrphidae. The diversity of the aphidophagous predators was shown to be higher on nettle than in field crops, particularly the Chrysopidae, the Anthocoridae and the Miridae. However, a striking difference of ladybird abundance was observed according to the aphid host plant. In one side, Coccinella septempunctata was much more abundant on Acyrthosiphon pisum infested green pea than on the other host plant species. At the opposite, higher occurrence of Harmonia axyridis was observed on the aphid infested nettle plants than on the crop plants. In particular, none of H. axyridis was found in wheat crop. Also, more than only a significant positive correlation between predator and aphid abundance, specialised relations between particular aphid species and some so-called generalist predators was determined in the fields. Finally, intraguild interactions between the aphidophagous predators was assessed and shown that only a significant negative correlation between Episyrphus balteatus and H. axyridis related to the nettle aphid, Micrlophium carnosum, was observed. The relative distribution of the ladybirds, namely C. septempunctata and H. axyridis according to the host plant, nettle strips and crop plots was discussed in relation to integrated pest management approach. [less ▲]Detailed reference viewed: 65 (9 ULg)
Evaluation of hoverfly Episyrphus balteatus De Geer (Diptera: Syrphidae) oviposition behaviour toward aphid-infested plants using a leaf disc system.
; Verheggen, François ; Francis, Frédéric et al
in Communications in Agricultural and Applied Biological Sciences (2006), 71(2 Pt B), 403-12
Several aphidophagous beneficials such as parasitoids and predators are known to respond positively to aphid infested plants. Semiochemicals from the latter association play an important role in the ... [more ▼]
Several aphidophagous beneficials such as parasitoids and predators are known to respond positively to aphid infested plants. Semiochemicals from the latter association play an important role in the foraging of predators in a tritrophic approach. In this work, three host plants infested with green peach aphid, Myzus persicae Sulzer were used to study the effect of prey density and aphid colony location on plant toward Episyrphus balteatus female. Their reproductive behaviour and efficiency (in terms of fecundity) were observed in net cages. Three kinds of experiments were performed using a disc leaf on agar diet in small Petri dishes under different conditions: 1) leaf disc of broad bean (Vicia faba) were infested with different aphid prey densities, 2) three host plants (Vicia faba, Solanum tuberosum, Solanum nigrum) infested with 3 different aphid prey densities and 3) three different heights of aphid colony location on V. faba plant infested with constant aphid density were also tested using leaf disc system. Aphid-free leaf discs were also used as control for predator behaviour observations. Oviposition rates of hoverfly on leaf disc system vary significantly with prey aphid densities. The means of eggs per laying were 0.9, 5.3, and 31.2 for 0, 10 and 100 aphid densities respectively. E. balteatus females were also able to evaluate and adjust oviposition rates according to different aphid prey densities/host plant. The 5 and 20 cm stakes were the most attractive heights of aphid colony location for the hoverfly oviposition. The means of eggs per laying were 16.7, 18.5 and 5.8 for 5, 20 and 40cm heights respectively. Our leaf disc system was found to be a practical and efficient way to assess chemical cues from aphids according to different conditions on the hoverfly reproductive behaviour. [less ▲]Detailed reference viewed: 67 (3 ULg)
Use of artificial diet system to assess the potential bio-insecticide effect of a fungal lectin from Xerocomus chrysenteron (XCL) on Myzus persicae.
; ; et al
in Communications in Agricultural and Applied Biological Sciences (2006), 71(2 Pt B), 497-505
Lectins are carbohydrate binding proteins which are widely distributed in nature: they have been isolated from microorganisms, fungi, plants and animals. Many of these proteins were tested for their ... [more ▼]
Lectins are carbohydrate binding proteins which are widely distributed in nature: they have been isolated from microorganisms, fungi, plants and animals. Many of these proteins were tested for their potential biocide effect on lot of pests. Indeed, lectins can cause dramatic changes in the cellular morphology and metabolism, particularly on the digestive system of insect having ingested them, by lectin binding to membrane glycosyl groups of the digestive tract cells. A fungal lectin, namely Xerocomus Chrysenteron lectin (XCL) was previously purified and was shown to be toxic to several pests including aphids. At the cell level, an increase in the endocytosis, the induction of morphological changes such as the actin cytoskeleton shape was determined. In this work, the recombinant XCL was produced and was tested for its potential aphicide effect on Myzus persicae, a polyphagous aphid found on more than 400 host plant species and transmitting more than 100 viral diseases. We developed bioassays using different artificial diets incorporating a broad range of XCL concentrations (from 10 microgx ml(-1) to lmg.ml(-1)) to assess the potential negative effects of XCL on the development and reproduction of the M. persicae aphid. Significant mortality rates, changes of developmental durations and nymph production were observed depending on the XCL concentration in the artificial diet. Concanavalin A lectin was also used in a new range of experiments to compare the effects of the two lectins on the aphid biological parameters. According to the observed dose responses toward the XCL and Con-A lectins included in the artificial diet and the action mode of this kind of proteins, the perspectives of lectin use in pest control will be discussed. [less ▲]Detailed reference viewed: 35 (3 ULg)
Perception of aphid infested tomato plant volatiles by the predator Episyrphus balteatus
Verheggen, François ; ; et al
Poster (2006)Detailed reference viewed: 9 (0 ULg)
Characterisation of bio-insecticide proteins in industrial residues from pea seeds (Pisum sativum L.)
; ; Portetelle, Daniel et al
in Abstract book (2006)Detailed reference viewed: 16 (3 ULg)
Etude de la diversité des pucerons et des auxiliaires adiphages relative à la présence d'orties en bordures de champ
; Francis, Frédéric ; Bodson, Bernard et al
in Notes Fauniques de Gembloux (2006), 59(2), 121-124Detailed reference viewed: 35 (6 ULg)
Défense végétale, biotechnologies et développement de bio-insecticides
Francis, Frédéric ; Blecker, Christophe ; et al
in Abstract book (2006)Detailed reference viewed: 17 (2 ULg)
Proteomics to identify odorant binding proteins (OBPs) and Chemosensory Proteins (CSPs) from the Antennae and Tarsi of Tribolium brevicornis
; Francis, Frédéric ; De Pauw, Edwin et al
in Abstract book (2006)Detailed reference viewed: 32 (5 ULg)
Proteomic approach to investigate aphid - plant interactions
Francis, Frédéric ; ; De Pauw, Edwin et al
in Abstract book (2006)Detailed reference viewed: 12 (2 ULg)
Use of Gammarus pulex as biomarker model to assess the ecological quality of inland waters : a proteomic approach
Leroy, Delphine ; Francis, Frédéric ; et al
in Abstract book (2006)Detailed reference viewed: 101 (16 ULg)
DIGE application to investigate aphid adaptation to resistant host plant
Francis, Frédéric ; ; et al
in Abstract book (2006)Detailed reference viewed: 12 (1 ULg)