A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant.
In feeding, aphids inject saliva into plant tissues, gaining access to phloem sap and eliciting (and sometimes overcoming) plant responses. We are examining the involvement, in this aphid-plant interaction, of individual aphid proteins and enzymes, as identified in a salivary gland cDNA library. Here, we focus on a salivary protein we have arbitrarily designated Protein C002. We have shown, by using RNAi-based transcript knockdown, that this protein is important in the survival of the pea aphid (Acyrthosiphon pisum) on fava bean, a host plant. Here, we further characterize the protein, its transcript, and its gene, and we study the feeding process of knockdown aphids. The encoded protein fails to match any protein outside of the family Aphididae. By using in situ hybridization and immunohistochemistry, the transcript and the protein were localized to a subset of secretory cells in principal salivary glands. Protein C002, whose sequence contains an N-terminal secretion signal, is injected into the host plant during aphid feeding. By using the electrical penetration graph method on c002-knockdown aphids, we find that the knockdown affects several aspects of foraging and feeding, with the result that the c002-knockdown aphids spend very little time in contact with phloem sap in sieve elements. Thus, we infer that Protein C002 is crucial in the feeding of the pea aphid on fava bean.
Mutti
Navdeep S
NS
Department of Entomology, Kansas State University, Manhattan, KS 66506, USA.
Louis
Joe
J
Pappan
Loretta K
LK
Pappan
Kirk
K
Begum
Khurshida
K
Chen
Ming-Shun
MS
Park
Yoonseong
Y
Dittmer
Neal
N
Marshall
Jeremy
J
Reese
John C
JC
Reeck
Gerald R
GR
D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D004435:Eating / Q000502:physiology; D018628:Gene Dosage; D017344:Genes, Insect; D054884:Host-Pathogen Interactions / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D034622:RNA Interference; D011994:Recombinant Proteins / Q000235:genetics; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000502:physiology*; D031307:Vicia faba / Q000469:parasitology
D018076:DNA, Complementary; D019476:Insect Proteins; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides