Acyrthosiphon pisum
not annotated - annotated - LINNAEUS only
21199018
Analysis of expressed sequence tags from Maize mosaic rhabdovirus-infected gut tissues of Peregrinus maidis reveals the presence of key components of insect innate immunity.
The corn planthopper, Peregrinus maidis, causes direct feeding damage to plants and transmits Maize mosaic rhabdovirus (MMV) in a persistent-propagative manner. MMV must cross several insect tissue layers for successful transmission to occur, and the gut serves as an important barrier for rhabdovirus transmission. In order to facilitate the identification of proteins that may interact with MMV either by facilitating acquisition or responding to virus infection, we generated and analysed the gut transcriptome of P. maidis. From two normalized cDNA libraries, we generated a P. maidis gut transcriptome composed of 20,771 expressed sequence tags (ESTs). Assembly of the sequences yielded 1860 contigs and 14,032 singletons, and biological roles were assigned to 5793 (36%). Comparison of P. maidis ESTs with other insect amino acid sequences revealed that P. maidis shares greatest sequence similarity with another hemipteran, the brown planthopper Nilaparvata lugens. We identified 202 P. maidis transcripts with putative homology to proteins associated with insect innate immunity, including those implicated in the Toll, Imd, JAK/STAT, Jnk and the small-interfering RNA-mediated pathways. Sequence comparisons between our P. maidis gut EST collection and the currently available National Center for Biotechnology Information EST database collection for Ni. lugens revealed that a pathogen recognition receptor in the Imd pathway, peptidoglycan recognition protein-long class (PGRP-LC), is present in these two members of the family Delphacidae; however, these recognition receptors are lacking in the model hemipteran Acyrthosiphon pisum. In addition, we identified sequences in the P. maidis gut transcriptome that share significant amino acid sequence similarities with the rhabdovirus receptor molecule, acetylcholine receptor (AChR), found in other hosts. This EST analysis sheds new light on immune response pathways in hemipteran guts that will be useful for further dissecting innate defence response pathways to rhabdovirus infection.
21382108
Responses of the pea aphid transcriptome to infection by facultative symbionts.
Serratia symbiotica is a facultative symbiont of pea aphids (Acyrthosiphon pisum) that provides tolerance to heat stress. Although the phenotypic effects of facultative symbionts upon hosts have been studied in some detail, little is known about the molecular and genomic basis of these interactions. Previous studies show a large impact of S. symbiotica upon the aphid metabolome. Whole-genome transcriptional profiling and next-generation sequencing demonstrated expression of 94% of RefSeq genes from the pea aphid genome, providing the largest dataset to date on aphid gene expression. However, only 28 genes showed changes in expression with S. symbiotica infection, and these changes were of small magnitude. No expression differences in genes involved in innate immunity in other insects were observed. Therefore, the large metabolic impact of S. symbiotica is most likely a result of metabolism of the symbiont itself, or of post-transcriptional modification of host gene expression. Although S. symbiotica has a major influence on its host's metabolome and resistance to heat, it induces little change in gene expression in its host.