Immunity and other defenses in pea aphids, Acyrthosiphon pisum
1 Department of Biology, Emory University, O Wayne Rollins Research Center, 1510 E. Clifton Road NE, Atlanta, GA, 30322, USA
2 Interdisciplinary Research Center, Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
3 Université de Lyon, INRA, INSA-Lyon, IFR41 BioEnvironnement et Santé, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Bat. Louis-Pasteur 20 ave Albert-Einstein, F-69621 Villeurbanne, France
4 UMR Interactions Biotiques et Santé Végétale, INRA 1301-CNRS 6243-Université de Nice-Sophia Antipolis, 400 routes des Chappe, F-06903 Sophia-Antipolis cedex, France
5 Department of Nematology, Graduate Program in Genetics, Genomics and Bioinformatics, University of California, 900 University Ave, Riverside, CA 92521, USA
6 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
7 Genetics Otago and The Laboratory for Evolution and Development, Department of Biochemistry, University of Otago, Box 56, Dunedin 9054, New Zealand
8 USDA-ARS Bee Research Lab, BARC-East Bldg 476, Beltsville, MD 20705, USA
9 Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Doctor Aiguader 88, 08003 Barcelona, Spain
10 Department of Entomology, The Volcani Center, Bet Dagan 50250, Israel
11 Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València, Avenida Blasco Ibañez 13, 46071 València, Spain
12 CIBER en Epidemiología y Salud Pública (CIBEResp) and Centro Superior de Investigación en Salud Pública (CSISP), Conselleria de Sanidad (Generalitat Valenciana), Avenida de Cataluña 21, 46020 València, Spain
13 Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
14 Plant Pathology and Plant-Microbe Biology Department, Cornell University, Tower Road, Ithaca, NY 14853, USA
15 Department of Entomology, Texas A&M, College Station, TX 77843-2475, USA
Genome Biology 2010, 11:R21 doi:10.1186/gb-2010-11-2-r21Published: 23 February 2010
Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders. Using the recently sequenced genome of the pea aphid (Acyrthosiphon pisum), we conducted the first extensive annotation of the immune and stress gene repertoire of a hemipterous insect, which is phylogenetically distantly related to previously characterized insects models.
Strikingly, pea aphids appear to be missing genes present in insect genomes characterized to date and thought critical for recognition, signaling and killing of microbes. In line with results of gene annotation, experimental analyses designed to characterize immune response through the isolation of RNA transcripts and proteins from immune-challenged pea aphids uncovered few immune-related products. Gene expression studies, however, indicated some expression of immune and stress-related genes.
The absence of genes suspected to be essential for the insect immune response suggests that the traditional view of insect immunity may not be as broadly applicable as once thought. The limitations of the aphid immune system may be representative of a broad range of insects, or may be aphid specific. We suggest that several aspects of the aphid life style, such as their association with microbial symbionts, could facilitate survival without strong immune protection.