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Genome Sequence Of The Pea Aphid Acyrthosiphon Pisum, The International Aphid Genomics Consortium

Biology Articles and Papers

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. …

Genomic Resources For Myzus Persicae: Est Sequencing, Snp Identification, And Microarray Design, John S. Ramsey, Alex C. C. Wilson, Marin De Vos, Qi Sun, Cecilia Tamborindeguy, Agnese Winfield, Gaynor Malloch, Dawn M. Smith, Brian Fenton, Stewart M. Gray, Georg Jander

Biology Articles and Papers

Backgorund

The green peach aphid, Myzus persicae (Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by M. persicae in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species.

Results

Sequencing of 16 M. persicae cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on Arabidopsis thaliana, Nicotiana benthamiana, Brassica oleracea, B. napus, and Physalis floridana (with and without Potato leafroll virus infection). The …

Aphid Thermal Tolerance Is Governed By A Point Mutation In Bacterial Symbionts, Helen E. Dunbar, Alex C. C. Wilson, Nicole R. Ferguson, Nancy A. Moran

Biology Articles and Papers

Symbiosis is a ubiquitous phenomenon generating biological complexity, affecting adaptation, and expanding ecological capabilities. However, symbionts, which can be subject to genetic limitations such as clonality and genomic degradation, also impose constraints on hosts. A model of obligate symbiosis is that between aphids and the bacterium Buchnera aphidicola, which supplies essential nutrients. We report a mutation in Buchnera of the aphid Acyrthosiphon pisum that recurs in laboratory lines and occurs in field populations. This single nucleotide deletion affects a homopolymeric run within the heat-shock transcriptional promoter for ibpA, encoding a small heat-shock protein. This Buchnera mutation virtually eliminates the transcriptional …

A Dual-Genome Microarray For The Pea Aphid, Acyrthosiphon Pisum, And Its Obligate Bacterial Symbiont, Buchnera Aphidicola, Alex C. C. Wilson, Helen E. Dunbar, Gregory K. Davis, Wayne B. Hunter, David L. Stern, Nancy A. Moran

Biology Articles and Papers

Background

The best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont Buchnera aphidicola. Buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. We have used a single microarray to examine gene expression in the pea aphid, Acyrthosiphon pisum, and its resident Buchnera. Very little is known of gene expression in aphids, few studies have examined gene expression in Buchnera, and no study has examined simultaneously the expression profiles of a host and its symbiont. Expression profiling …

The Genetic Outcomes Of Sex And Recombination In Long-Term Functionally Parthenogenetic Lineages Of Australian Sitobion Aphids, Alex C. C. Wilson, Paul Sunnucks

Biology Articles and Papers

The typical life cycle of an aphid is cyclical parthenogenesis which involves the alternation of sexual and asexual reproduction. However, aphid life cycles, even within a species, can encompass everything on a continuum from obligate sexuality, through facultative sexuality to obligate asexuality. Loss of the sexual cycle in aphids is frequently associated with the introduction of a new pest and can occur for a number of environmental and genetic reasons. Here we investigate loss of sexual function in Sitobion aphids in Australia. Specifically, we aimed to determine whether an absence of sexual reproduction in Australian Sitobion results from genetic loss …

Isolation Of A Cdna Encoding A Kex2-Like Endoprotease With Homology To Furin From The Nematode Caenorhabditis Elegans, Eduardo Gomez-Saladin, Anne E. Luebke, David L. Wilson, Ian M. Dickerson

Biology Articles and Papers

A cDNA was isolated from the nematode Caenorhabditis elegans that encodes an endoprotease which is a member of the Kex2 family of serine endoproteases. Degenerate oligonucleotide primers were designed based on conserved regions within the active sites of known Kex2-like endoproteases, and were used for reverse transcription-polymerase chain reaction (RT-PCR) of poly(A)⁺RNA isolated from C. elegans. A PCR product was isolated that had homology to the active sites of known furin endoproteases, and was used as a probe to screen a C. elegans cDNA library. A Kex2-like endoprotease (CelfurPC) which encoded a 692-amino-acid preproendoprotease, was identified. The …

Modification Of A Rapidly Transported Protein In Regenerating Nerve, Bruce Tedeschi, David L. Wilson

Biology Articles and Papers

From 1 to 28 days after frog sciatic nerve damage, dorsal root ganglia were incubated with [35S] methionine, and the labeled, rapidly transported proteins at various points along the nerve were analyzed on two-dimensional gels. The results show a dramatic increase in the labeling of a protein, which we have designated as A25, only after the arrival of the rapidly transported proteins at regenerating nerve tips. This effect is first seen 3 to 5 days after injury. On gels from regenerating nerves, A25 appears as a series of intense spots with an apparent molecular weight of 70,000. A25 is retrogradely …

Patterns Of Proteins Synthesized In The R15 Neuron Of Aplysia: Temporal Studies And Evidence For Processing, F. Strumwasser, David L. Wilson

Biology Articles and Papers

The time-course of changes in the pattern of newly synthesized proteins in the R15 neuron of the parietovisceral ganglion of Aplysia californica has been studied at 14 degrees C. 5% polyacrylamide gels containing sodium dodecyl sulfate (SDS) have been used to separate newly synthesized (leucine-labeled) proteins from the neuron. We have demonstrated that the pattern of newly synthesized proteins from the R15 neuron does not change significantly if 5-h pulses of labeled leucine are given during the first 72 h of in vitro incubation of the excised ganglion. However, the level of leucine incorporation begins to decline somewhere between 17 …

Molecular Weight Distribution Of Proteins Synthesized In Single, Identified Neurons Of Aplysia, David L. Wilson

Biology Articles and Papers

Parietovisceral ganglia from Aplysia californica were incubated in medium containing leucine-³H. Single, identified nerve cell somas were isolated from the ganglia, and their proteins extracted and separated by electrophoresis on 5% SDS-polyacrylamide gels. The distribution of total or newly synthesized proteins from the single neurons was determined by staining or slicing and liquid scintillation counting of the gels. Experiments showed that: (a) a number of proteins were being synthesized in abundance in the nerve cells; (b) different, identified neurons showed reproducibly different labeling patterns in the gels; (c) cells R2 and R15, …