148 research outputs found

    Socio-economic voter profile and motives for Islamist support in Morocco

    Get PDF
    Based on an original dataset of merged electoral and census data, this article is a study of electoral support for the Islamist Party in Morocco in the 2002 and 2007 elections. It differentiates between the clientelistic, grievance and horizontal network type of supporters. We disentangle these profiles empirically on the basis of the role of education, wealth and exclusion for Islamist votes. We find no evidence of the clientelistic profile, but a shift from grievance in 2002 to a horizontal network profile in 2007. World Values Survey individual level data are used as a robustness check, yielding similar results. Qualitative evidence on a changing mobilization pattern of the party between 2002 and 2007 supports our conclusions

    Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

    Get PDF
    Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components

    A protease cascade regulates release of the human malaria parasite Plasmodium falciparum from host red blood cells

    Get PDF
    Malaria parasites replicate within a parasitophorous vacuole in red blood cells (RBCs). Progeny merozoites egress upon rupture of first the parasitophorous vacuole membrane (PVM), then poration and rupture of the RBC membrane (RBCM). Egress is protease-dependent1, but none of the effector molecules that mediate membrane rupture have been identified and it is unknown how sequential rupture of the two membranes is controlled. Minutes before egress, the parasite serine protease SUB1 is discharged into the parasitophorous vacuole2,3,4,5,6 where it cleaves multiple substrates2,5,7,8,9 including SERA6, a putative cysteine protease10,11,12. Here, we show that Plasmodium falciparum parasites lacking SUB1 undergo none of the morphological transformations that precede egress and fail to rupture the PVM. In contrast, PVM rupture and RBCM poration occur normally in SERA6-null parasites but RBCM rupture does not occur. Complementation studies show that SERA6 is an enzyme that requires processing by SUB1 to function. RBCM rupture is associated with SERA6-dependent proteolytic cleavage within the actin-binding domain of the major RBC cytoskeletal protein β-spectrin. We conclude that SUB1 and SERA6 play distinct, essential roles in a coordinated proteolytic cascade that enables sequential rupture of the two bounding membranes and culminates in RBCM disruption through rapid, precise, SERA6-mediated disassembly of the RBC cytoskeleton

    Anti-tumor effect of adenovirus-mediated gene transfer of pigment epithelium-derived factor on mouse B16-F10 melanoma

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Angiogenesis plays an important role in tumor growth, invasion, and eventually metastasis. Antiangiogenic strategies have been proven to be a promising approach for clinical therapy for a variety of tumors. As a potent inhibitor of tumor angiogenesis, pigment epithelium-derived factor (PEDF) has recently been studied and used as an anticancer agent in several tumor models.</p> <p>Methods</p> <p>A recombined adenovirus carrying PEDF gene (Ad-PEDF) was prepared, and its expression by infected cells and in treated animals was confirmed with Western blotting and ELISA, respectively. Its activity for inhibiting human umbilical vein endothelial cell (HUVEC) proliferation was tested using the MTT assay. C57BL/6 mice bearing B16-F10 melanoma were treated with i.v. administration of 5 × 10<sup>8 </sup>IU/mouse Ad-PEDF, or 5 × 10<sup>8 </sup>IU/mouse Ad-Null, or normal saline (NS), every 3 days for a total of 4 times. Tumor volume and survival time were recorded. TUNEL, CD31 and H&E stainings of tumor tissue were conducted to examine apoptosis, microvessel density and histological morphology changes. Antiangiogenesis was determined by the alginate-encapsulated tumor cell assay.</p> <p>Results</p> <p>The recombinant PEDF adenovirus is able to transfer the PEDF gene to infected cells and successfully produce secretory PEDF protein, which exhibits potent inhibitory effects on HUVEC proliferation. Through inhibiting angiogenesis, reducing MVD and increasing apoptosis, Ad-PEDF treatment reduced tumor volume and prolonged survival times of mouse bearing B16-F10 melanoma.</p> <p>Conclusion</p> <p>Our data indicate that Ad-PEDF may provide an effective approach to inhibit mouse B16-F10 melanoma growth.</p

    An EGF-like Protein Forms a Complex with PfRh5 and Is Required for Invasion of Human Erythrocytes by Plasmodium falciparum

    Get PDF
    Invasion of erythrocytes by Plasmodium falciparum involves a complex cascade of protein-protein interactions between parasite ligands and host receptors. The reticulocyte binding-like homologue (PfRh) protein family is involved in binding to and initiating entry of the invasive merozoite into erythrocytes. An important member of this family is PfRh5. Using ion-exchange chromatography, immunoprecipitation and mass spectroscopy, we have identified a novel cysteine-rich protein we have called P. falciparum Rh5 interacting protein (PfRipr) (PFC1045c), which forms a complex with PfRh5 in merozoites. Mature PfRipr has a molecular weight of 123 kDa with 10 epidermal growth factor-like domains and 87 cysteine residues distributed along the protein. In mature schizont stages this protein is processed into two polypeptides that associate and form a complex with PfRh5. The PfRipr protein localises to the apical end of the merozoites in micronemes whilst PfRh5 is contained within rhoptries and both are released during invasion when they form a complex that is shed into the culture supernatant. Antibodies to PfRipr1 potently inhibit merozoite attachment and invasion into human red blood cells consistent with this complex playing an essential role in this process

    A herbivore tag-and-trace system reveals contact- and density-dependent repellence of a root toxin

    Get PDF
    Foraging behavior of root feeding organisms strongly affects plant-environment-interactions and ecosystem processes. However, the impact of plant chemistry on root herbivore movement in the soil is poorly understood. Here, we apply a simple technique to trace the movement of soil-dwelling insects in their habitats without disturbing or restricting their interactions with host plants. We tagged the root feeding larvae of Melolontha melolontha with a copper ring and repeatedly located their position in relation to their preferred host plant, Taraxacum officinale, using a commercial metal detector. This method was validated and used to study the influence of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) on the foraging of M. melolontha. TA-G is stored in the latex of T. officinale and protects the roots from herbivory. Using behavioral arenas with TA-G deficient and control plants, we tested the impact of physical root access and plant distance on the effect of TA-G on M. melolontha. The larvae preferred TA-G deficient plants to control plants, but only when physical root contact was possible and the plants were separated by 5 cm. Melolontha melolontha showed no preference for TA-G deficient plants when the plants were grown 15 cm apart, which may indicate a trade-off between the cost of movement and the benefit of consuming less toxic food. We demonstrate that M. melolontha integrates host plant quality and distance into its foraging patterns and suggest that plant chemistry affects root herbivore behavior in a plant-density dependent manner. © 2017, Springer Science+Business Media New York

    SILEX: a fast and inexpensive high-quality DNA extraction method suitable for multiple sequencing platforms and recalcitrant plant species

    Full text link
    [EN] Background The use of sequencing and genotyping platforms has undergone dramatic improvements, enabling the generation of a wealth of genomic information. Despite this progress, the availability of high-quality genomic DNA (gDNA) in sufficient concentrations is often a main limitation, especially for third-generation sequencing platforms. A variety of DNA extraction methods and commercial kits are available. However, many of these are costly and frequently give either low yield or low-quality DNA, inappropriate for next generation sequencing (NGS) platforms. Here, we describe a fast and inexpensive DNA extraction method (SILEX) applicable to a wide range of plant species and tissues. Results SILEX is a high-throughput DNA extraction protocol, based on the standard CTAB method with a DNA silica matrix recovery, which allows obtaining NGS-quality high molecular weight genomic plant DNA free of inhibitory compounds. SILEX was compared with a standard CTAB extraction protocol and a common commercial extraction kit in a variety of species, including recalcitrant ones, from different families. In comparison with the other methods, SILEX yielded DNA in higher concentrations and of higher quality. Manual extraction of 48 samples can be done in 96 min by one person at a cost of 0.12 euro/sample of reagents and consumables. Hundreds of tomato gDNA samples obtained with either SILEX or the commercial kit were successfully genotyped with Single Primer Enrichment Technology (SPET) with the Illumina HiSeq 2500 platform. Furthermore, DNA extracted fromSolanum elaeagnifoliumusing this protocol was assessed by Pulsed-field gel electrophoresis (PFGE), obtaining a suitable size ranges for most sequencing platforms that required high-molecular-weight DNA such as Nanopore or PacBio. Conclusions A high-throughput, fast and inexpensive DNA extraction protocol was developed and validated for a wide variety of plants and tissues. SILEX offers an easy, scalable, efficient and inexpensive way to extract DNA for various next-generation sequencing applications including SPET and Nanopore among others.This research has been funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No 677379 (Linking genetic resources, genomes and phenotypes of Solanaceous crops; G2P-SOL). David Alonso is grateful to Universitat Politecnica de Valencia for a predoctoral (PAID-01-16) contract under the Programa de Ayudas de Investigacion y Desarrollo initiative. Mariola Plazas is grateful to Generalitat Valenciana and Fondo Social Europeo for a postdoctoral grant (APOSTD/2018/014). Pietro Gramazio is grateful to Japan Society for the Promotion of Science for a Postdoctoral Grant (P19105, FY2019 JSPS Postdoctoral Fellowship for Research in Japan (Standard)). The Spanish Ministerio de Educacion, Cultura y Deporte funded a predoctoral fellowship granted to Edgar Garcia-Fortea (FPU17/02389).Vilanova Navarro, S.; Alonso-Martín, D.; Gramazio, P.; Plazas Ávila, MDLO.; García-Fortea, E.; Ferrante, P.; Schmidt, M.... (2020). SILEX: a fast and inexpensive high-quality DNA extraction method suitable for multiple sequencing platforms and recalcitrant plant species. Plant Methods. 16(1):1-11. https://doi.org/10.1186/s13007-020-00652-yS111161Scheben A, Batley J, Edwards D. Genotyping-by-sequencing approaches to characterize crop genomes: choosing the right tool for the right application. Plant Biotechnol J. 2017;15:149–61.Jung H, Winefield C, Bombarely A, Prentis P, Waterhouse P. Tools and strategies for long-read sequencing and de novo assembly of plant genomes. Trends Plant Sci. 2019;24:700–24.Elshire RJ, Glaubitz JC, Sun Q, Poland JA, Kawamoto K, Buckler ES, Mitchell SE. A robust, simple genotyping-by-sequencing (GBS) approach for high diversity species. PLoS ONE. 2011;6:e19379.Baird NA, Etter PD, Atwood TS, Currey MC, Shiver AL, Lewis ZA, Selker EU, Cresko WA, Johnson EA. Rapid SNP discovery and genetic mapping using sequenced RAD markers. PLoS ONE. 2008;3:e3376.Scaglione D, Pinosio S, Marroni F, Centa E, Fornasiero A, Magris G, Scalabrin S, Cattonaro F, Taylor G, Morgante M. Single primer enrichment technology as a tool for massive genotyping: a benchmark on black poplar and maize. Ann Bot. 2019;124:543–51.Barchi L, Acquadro A, Alonso D, Aprea G, Bassolino L, Demurtas O, Ferrante P, Gramazio P, Mini P, Portis E, Scaglione D, Toppino L, Vilanova S, Díez MJ, Rotino G, Lanteri S, Prohens J, Giuliano G. Single primer enrichment technology (SPET) for high-throughput genotyping in tomato and eggplant germplasm. Front Plant Sci. 2019;10:1005.Vaillancourt B, Buell CR. High molecular weight DNA isolation method from diverse plant species for use with Oxford Nanopore sequencing. bioRxiv. 2019;1:783159.Anderson CB, Franzmayr BK, Hong SW, Larking AC, van Stijn TC, Tan R, Moraga R, Faville M, Griffiths A. Protocol: a versatile, inexpensive, high-throughput plant genomic DNA extraction method suitable for genotyping-by-sequencing. Plant Methods. 2018;14:75.Rana MM, Aycan M, Takamatsu T, Kaneko K, Mitsui T, Itoh K. Optimized nuclear pellet method for extracting next-generation sequencing quality genomic DNA from fresh leaf tissue. Methods Protoc. 2019;2:54.Doyle JJ, Doyle JL. Isolation of plant DNA from fresh tissue. Focus. 1990;12:13–5.Healey A, Furtado A, Cooper T, Henry RJ. Protocol: a simple method for extracting next-generation sequencing quality genomic DNA from recalcitrant plant species. Plant Methods. 2014;10:21.Martínez-González CR, Ramírez-Mendoza R, Jiménez-Ramírez J, Gallegos-Vázquez C, Luna-Vega I. Improved method for genomic DNA extraction for Opuntia Mill. (Cactaceae). Plant Methods. 2017;13:82.Barbier FF, Chabikwa TG, Ahsan MU, Cook SE, Powell R, Tanurdzic M, Beveridge C. A phenol/chloroform-free method to extract nucleic acids from recalcitrant, woody tropical species for gene expression and sequencing. Plant Methods. 2019;15:62.Souza DC, Teixeira TA. A simple and effective method to obtain high DNA quality and quantity from Cerrado plant species. Mol Biol Rep. 2019;46:4611–5.Kovačević N. Magnetic beads based nucleic acid purification for molecular biology applications. Sample preparation techniques for soil, plant, and animal samples. In: Micic M, editor. Springer Protoc Handb. 2016;53–67.Martin SL, Parent JS, Laforest M, Page E, Kreiner JM, James T. Population genomic approaches for weed science. Plants. 2019;8:354.Zhou Y, Zhang Y, He W, Wang J, Peng F, Huang L, Zhao S, Deng W. Rapid regeneration and reuse of silica columns from PCR purification and gel extraction kits. Sci Rep. 2018;8:12870.Park HJ, Cho H, Jung HS, Cho BH, Lee MY. Development of a DNA isolation device using poly(3,4-dihydroxy-l-phenylalanine)-coated swab for on-site molecular diagnostics. Sci Rep. 2019;9:8144.Boom R, Sol CJ, Salimans MM, Jansen CL, Wertheim-van Dillen PM, van der Noordaa J. Rapid and simple method for purification of nucleic acids. J Clin Microbiol. 1990;28:495–503.Carter MJ, Milton ID. An inexpensive and simple method for DNA purifications on silica particles. Nucleic Acids Res. 1993;21:1044.Carvalho J, Puertas G, Gaspar J, Azinheiro S, Diéguez L, Garrido-Maestu A, Vázquez M, Barros-Velázquez J, Cardoso S, Padro M. Highly efficient DNA extraction and purification from olive oil on a washable and reusable miniaturized device. Anal Chim Acta. 2018;1020:30–40.Branton D, Deamer D, Quick J, Loman NJ. DNA extraction strategies for nanopore sequencing. Nanopore Seq. World Sci. 2019;1:91–105.Cheng H, Zhang K, Libera J, De La Cruz M, Bedzyk M. Polynucleotide adsorption to negatively charged surfaces in divalent salt solutions. Biophys J. 2016;90:1164–74.Shi B, Shin Y, Hassanali A, Singer S. DNA Binding to the Silica Surface. J Phys Chem B. 2015;119:11030–40.Katevatis C, Fan A, Klapperich CM. Low concentration DNA extraction and recovery using a silica solid phase. PLoS ONE. 2017;12:e0176848.Green MR, Sambrook J. Isolation and quantification of DNA. Cold Spring Harb Protoc. 2018;2018:403–14.Toole K, Roffey P, Young E, Cho K, Shaw T, Smith M, Blagojevic N. Evaluation of commercial forensic DNA extraction kits for decontamination and extraction of DNA from biological samples contaminated with radionuclides. Forensic Sci Int. 2019;302:109867.Piskata Z, Servusova E, Babak V, Nesvadbova M, Borilova G. The quality of DNA isolated from processed food and feed via different extraction procedures. Molecules. 2019;24:1188.Xia Y, Chen F, Du Y, Liu C, Bu G, Xin Y, Boye L. A modified SDS-based DNA extraction method from raw soybean. Biosci Rep. 2019;39:2.Akkurt M. Comparison between modified DNA extraction protocols and commercial isolation kits in grapevine (Vitis vinifera L.). Genet Mol Res. 2012;11:2343–51.Marsal G, Baiges I, Canals JM, Zamora F, Fort F. A Fast, efficient method for extracting DNA from leaves, stems, and seeds of Vitis vinifera L. Am J Enol Vitic. 2011;62:376–81.Abdel-Latif A, Osman G. Comparison of three genomic DNA extraction methods to obtain high DNA quality from maize. Plant Methods. 2017;13:1.Huang J, Ge X, Sun M. Modified CTAB protocol using a silica matrix for isolation of plant genomic DNA. Biotechniques. 2000;28:432–4.Rogstad SH. Plant DNA extraction using silica. Plant Mol Biol Report. 2012;21:463.Li J-F, Li L, Sheen J. Protocol: a rapid and economical procedure for purification of plasmid or plant DNA with diverse applications in plant biology. Plant Methods. 2010;6:1.Li J-F, Sheen J. DNA purification from multiple sources in plant research with homemade silica resins. Humana Press. 2012;862:53–9.Vandeventer PE, Lin JS, Zwang TJ, Nadim A, Johal MS, Niemz A. Multiphasic DNA adsorption to silica surfaces under varying buffer, pH, and ionic strength conditions. J Phys Chem B. 2012;116:5661–70.Boesenberg-Smith KA, Pessarakli MM, Wolk DM. Assessment of DNA yield and purity: an overlooked detail of PCR troubleshooting. Clin Microbiol Newsl. 2012;34:1–6.Emaus MN, Clark KD, Hinners P, Anderson JL. Preconcentration of DNA using magnetic ionic liquids that are compatible with real-time PCR for rapid nucleic acid quantification. Anal Bioanal Chem. 2018;410:4135–44.Dumschott K, Schmidt MHW, Chawla HS, Snowdon R, Usadel B. Oxford Nanopore sequencing: new opportunities for plant genomics? J Exp Bot. 2020;eraa263Knapp S, Sagona E, Carbonell AKZ, Chiarini F. A revision of the Solanum elaeagnifolium clade (Elaeagnifolium clade; subgenus Leptostemonum, Solanaceae). PhytoKeys. 2017;84:1–104.García-Fortea E, Gramazio P, Vilanova S, Fita A, Mangino G, Villanueva G, Arrones A, Knapp S, Prohens J, Plazas M. First successful backcrossing towards eggplant (Solanum melongena) of a New World species, the silverleaf nightshade (S. elaeagnifolium), and characterization of interspecific hybrids and backcrosses. Sci Hort. 2019;246:563–73.Ihaka R, Gentleman R. R: a language for data analysis and graphics. J Comput Graph Stat. 1996;5:3299–314.Wickham H. ggplot2: Elegant graphics for data analysis. New York: Springer-Verlag; 2016.Ponti G, Maccaferri M, Manfredini M, Kaleci S, Mandrioli M, Pellacani G, Ozben T, Depenni R, Bianchi G, Pirola G, Tomasi A. The value of fluorimetry (Qubit) and spectrophotometry (NanoDrop) in the quantification of cell-free DNA (cfDNA) in malignant melanoma and prostate cancer patients. Clin Chim Acta. 2018;479:14–9.Lakshmi R, Baskar V, Ranga U. Extraction of superior-quality plasmid DNA by a combination of modified alkaline lysis and silica matrix. Anal Biochem. 1999;272:109–12.Taylor JI, Hurst CD, Davies MJ, Sachsinger N, Bruce IJ. Application of magnetite and silica–magnetite composites to the isolation of genomic DNA. J Chromatogr A. 2000;890:159–66.Prodělalová J, Rittich B, Španová A, Petrová K, Beneš MJ. Isolation of genomic DNA using magnetic cobalt ferrite and silica particles. J Chromatogr A. 2004;1056:43–8.Shan Z, Jiang Y, Guo M, Bennett JC, Li X, Tian H, Oakes K, Zhang, Zhou Y, Huang Q, Chen H. Promoting DNA loading on magnetic nanoparticles using a DNA condensation strategy. Colloids Surfaces B Biointerfaces. 2015;125:247–54.Greco M, Sáez C, Brown M, Bitonti M. A simple and effective method for high quality co-extraction of genomic DNA and total RNA from low biomass Ectocarpus siliculosus, the model brown alga. PLoS ONE. 2014;9:e96470.Schrader C, Schielke A, Ellerbroek L, Johne R. PCR inhibitor – occurrence, properties and removal. J Appl Microbiol. 2012;113:1014–26.Demeke T, Adams RP. The effects of plant polysaccharides and buffer additives on PCR. Biotechniques. 1992;12:332–4.Asami DK, Hong YJ, Barrett DM, Mitchell AE. Comparison of the total phenolic and ascorbic acid content of freeze-dried and air-dried marionberry, strawberry, and corn grown using conventional, organic, and sustainable agricultural practices. J Agric Food Chem. 2003;51:1237–41.Schmidt M, Vogel A, Denton A, Istace B, Wormit A, van de Geest H, Bolger M, Alseekh S, Maß J, Pfaff C, Schurr U, Chetelat R, Maumus F, Aury J, Koren S, Fernie A, Zamir D, Bolger A, Usadel B. De novo assembly of a new Solanum pennellii accession using nanopore sequencing. Plant cell. 2017;29:2336–48

    Viral Capsid Is a Pathogen-Associated Molecular Pattern in Adenovirus Keratitis

    Get PDF
    Human adenovirus (HAdV) infection of the human eye, in particular serotypes 8, 19 and 37, induces the formation of corneal subepithelial leukocytic infiltrates. Using a unique mouse model of adenovirus keratitis, we studied the role of various virus-associated molecular patterns in subsequent innate immune responses of resident corneal cells to HAdV-37 infection. We found that neither viral DNA, viral gene expression, or viral replication was necessary for the development of keratitis. In contrast, empty viral capsid induced keratitis and a chemokine profile similar to intact virus. Transfected viral DNA did not induce leukocyte infiltration despite CCL2 expression similar to levels in virus infected corneas. Mice without toll-like receptor 9 (Tlr9) signaling developed clinical keratitis upon HAdV-37 infection similar to wild type mice, although the absolute numbers of activated monocytes in the cornea were less in Tlr9−/− mice. Virus induced leukocytic infiltrates and chemokine expression in mouse cornea could be blocked by treatment with a peptide containing arginine glycine aspartic acid (RGD). These results demonstrate that adenovirus infection of the cornea induces chemokine expression and subsequent infiltration by leukocytes principally through RGD contact between viral capsid and the host cell, possibly through direct interaction between the viral capsid penton base and host cell integrins

    Towards a collaborative research: A case study on linking science to farmers' perceptions and knowledge on Arabica coffee pests and diseases and its management

    Get PDF
    The scientific community has recognized the importance of integrating farmer's perceptions and knowledge (FPK) for the development of sustainable pest and disease management strategies. However, the knowledge gap between indigenous and scientific knowledge still contributes to misidentification of plant health constraints and poor adoption of management solutions. This is particularly the case in the context of smallholder farming in developing countries. In this paper, we present a case study on coffee production in Uganda, a sector depending mostly on smallholder farming facing a simultaneous and increasing number of socio-ecological pressures. The objectives of this study were (i) to examine and relate FPK on Arabica Coffee Pests and Diseases (CPaD) to altitude and the vegetation structure of the production systems; (ii) to contrast results with perceptions from experts and (iii) to compare results with field observations, in order to identify constraints for improving the information flow between scientists and farmers. Data were acquired by means of interviews and workshops. One hundred and fifty farmer households managing coffee either at sun exposure, under shade trees or inter-cropped with bananas and spread across an altitudinal gradient were selected. Field sampling of the two most important CPaD was conducted on a subset of 34 plots. The study revealed the following findings: (i) Perceptions on CPaD with respect to their distribution across altitudes and perceived impact are partially concordant among farmers, experts and field observations (ii) There are discrepancies among farmers and experts regarding management practices and the development of CPaD issues of the previous years. (iii) Field observations comparing CPaD in different altitudes and production systems indicate ambiguity of the role of shade trees. According to the locality-specific variability in CPaD pressure as well as in FPK, the importance of developing spatially variable and relevant CPaD control practices is proposed. (Résumé d'auteur
    corecore