title: Secretome of fungus-infected aphids documents high pathogen activity and weak host response.
abstract: The discovery of novel secretome proteins can add to our understanding of host-pathogen interactions. Here we report a rich diversity of secreted proteins from the interaction between grain aphids (host, insect order Hemiptera) and fungi of the order Entomophthorales (insect pathogens). The proteins were identified using a unique method unbiased by known sequences or functions to screen a cDNA library constructed directly from field-sampled material. We show for the first time that fungi from the genera Pandora and Entomophthora are armed with a battery of hydrolytic enzymes for penetrating the host cuticle. This enables both access to the hemolymph and exit for sporulation. Further, they secrete enzymes, most notably a number of lipases, for digestion of easily accessible high-energy compounds in the hemolymph. In contrast, we identified only few host genes potentially involved in the interaction, indicating that aphids respond only weakly to the pathogens. These results support recent findings that aphids have a reduced immune repertoire.
authors.affiliation: Department of Biotechnology and Chemistry, Section for Sustainable Biotechnology, Aalborg University, Lautrupvang 15, DK-2750 Ballerup, Denmark. mng@bio.aau.dk
authors.forename: Morten N
authors.initials: MN
authors.lastname: Grell
authors.forename: Annette B
authors.initials: AB
authors.lastname: Jensen
authors.forename: Peter B
authors.initials: PB
authors.lastname: Olsen
authors.forename: Jørgen
authors.initials: J
authors.lastname: Eilenberg
authors.forename: Lene
authors.initials: L
authors.lastname: Lange
mesh_terms: D000818:Animals; D020091:Entomophthorales / Q000472:pathogenicity*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015723:Gene Library; D006430:Hemiptera / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D005656:Fungal Proteins; D019476:Insect Proteins