title: Predicted effector molecules in the salivary secretome of the pea aphid (Acyrthosiphon pisum): a dual transcriptomic/proteomic approach.
abstract: The relationship between aphids and their host plants is thought to be functionally analogous to plant-pathogen interactions. Although virulence effector proteins that mediate plant defenses are well-characterized for pathogens such as bacteria, oomycetes, and nematodes, equivalent molecules in aphids and other phloem-feeders are poorly understood. A dual transcriptomic-proteomic approach was adopted to generate a catalog of candidate effector proteins from the salivary glands of the pea aphid, Acyrthosiphon pisum. Of the 1557 transcript supported and 925 mass spectrometry identified proteins, over 300 proteins were identified with secretion signals, including proteins that had previously been identified directly from the secreted saliva. Almost half of the identified proteins have no homologue outside aphids and are of unknown function. Many of the genes encoding the putative effector proteins appear to be evolving at a faster rate than homologues in other insects, and there is strong evidence that genes with multiple copies in the genome are under positive selection. Many of the candidate aphid effector proteins were previously characterized in typical phytopathogenic organisms (e.g., nematodes and fungi) and our results highlight remarkable similarities in the saliva from plant-feeding nematodes and aphids that may indicate the evolution of common solutions to the plant-parasitic lifestyle.
authors.affiliation: UCD School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland.
authors.forename: James C
authors.initials: JC
authors.lastname: Carolan
authors.forename: Doina
authors.initials: D
authors.lastname: Caragea
authors.forename: Karen T
authors.initials: KT
authors.lastname: Reardon
authors.forename: Navdeep S
authors.initials: NS
authors.lastname: Mutti
authors.forename: Neal
authors.initials: N
authors.lastname: Dittmer
authors.forename: Kirk
authors.initials: K
authors.lastname: Pappan
authors.forename: Feng
authors.initials: F
authors.lastname: Cui
authors.forename: Marisol
authors.initials: M
authors.lastname: Castaneto
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.forename: Carole
authors.initials: C
authors.lastname: Dossat
authors.forename: Denis
authors.initials: D
authors.lastname: Tagu
authors.forename: John C
authors.initials: JC
authors.lastname: Reese
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Reeck
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Wilkinson
authors.forename: Owain R
authors.initials: OR
authors.lastname: Edwards
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000737:chemistry* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D019476:Insect Proteins / Q000032:analysis* / Q000145:classification / Q000235:genetics; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D010802:Phylogeny; D021382:Protein Sorting Signals / Q000235:genetics; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D012463:Saliva / Q000737:chemistry*; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; D021382:Protein Sorting Signals; D020543:Proteome