Genome Sequence of the Pea Aphid Acyrthosiphon pisum

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. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems

List of primers used for RT-qPCR from Cereal Weevil's antimicrobial peptides: at the crosstalk between development, endosymbiosis and immune response

Interactions between animals and microbes are ubiquitous in nature and strongly impact animal physiology. These interactions are shaped by the host immune system, which responds to infections and contributes to tailor the associations with beneficial microorganisms. In many insects, beneficial symbiotic associations not only include gut commensals, but also intracellular bacteria, or endosymbionts. Endosymbionts are housed within specialized host cells, the bacteriocytes, and are transmitted vertically across host generations. Host endosymbiont co-evolution shapes the endosymbiont genome and host immune system, which not only fights against microbial intruders, but also ensures the preservation of endosymbionts and the control of their load and location. The cereal weevil Sitophilus spp. is a remarkable model in which to study the evolutionary adaptation of the immune system to endosymbiosis owing to its binary association with a unique, relatively recently acquired nutritional endosymbiont, Sodalis pierantonius. This Gram-negative bacterium has not experienced the genome size shrinkage observed in long-term endosymbioses and has retained immunogenicity. We focus here on the sixteen antimicrobial peptides (AMPs) identified in the Sitophilus oryzae genome and their expression patterns in different tissues, along host development or upon immune challenges, to address their potential functions in the defensive response and endosymbiosis homeostasis along the insect life cycle.This article is part of the theme issue ‘Sculpting the microbiome: How host factors determine and respond to microbial colonisation’

Material and methods from Cereal Weevil's antimicrobial peptides: at the crosstalk between development, endosymbiosis and immune response

Interactions between animals and microbes are ubiquitous in nature and strongly impact animal physiology. These interactions are shaped by the host immune system, which responds to infections and contributes to tailor the associations with beneficial microorganisms. In many insects, beneficial symbiotic associations not only include gut commensals, but also intracellular bacteria, or endosymbionts. Endosymbionts are housed within specialized host cells, the bacteriocytes, and are transmitted vertically across host generations. Host endosymbiont co-evolution shapes the endosymbiont genome and host immune system, which not only fights against microbial intruders, but also ensures the preservation of endosymbionts and the control of their load and location. The cereal weevil Sitophilus spp. is a remarkable model in which to study the evolutionary adaptation of the immune system to endosymbiosis owing to its binary association with a unique, relatively recently acquired nutritional endosymbiont, Sodalis pierantonius. This Gram-negative bacterium has not experienced the genome size shrinkage observed in long-term endosymbioses and has retained immunogenicity. We focus here on the sixteen antimicrobial peptides (AMPs) identified in the Sitophilus oryzae genome and their expression patterns in different tissues, along host development or upon immune challenges, to address their potential functions in the defensive response and endosymbiosis homeostasis along the insect life cycle.This article is part of the theme issue ‘Sculpting the microbiome: How host factors determine and respond to microbial colonisation’

AMPs identified in the Sitophilus oryzae genome from Cereal Weevil's antimicrobial peptides: at the crosstalk between development, endosymbiosis and immune response

Interactions between animals and microbes are ubiquitous in nature and strongly impact animal physiology. These interactions are shaped by the host immune system, which responds to infections and contributes to tailor the associations with beneficial microorganisms. In many insects, beneficial symbiotic associations not only include gut commensals, but also intracellular bacteria, or endosymbionts. Endosymbionts are housed within specialized host cells, the bacteriocytes, and are transmitted vertically across host generations. Host endosymbiont co-evolution shapes the endosymbiont genome and host immune system, which not only fights against microbial intruders, but also ensures the preservation of endosymbionts and the control of their load and location. The cereal weevil Sitophilus spp. is a remarkable model in which to study the evolutionary adaptation of the immune system to endosymbiosis owing to its binary association with a unique, relatively recently acquired nutritional endosymbiont, Sodalis pierantonius. This Gram-negative bacterium has not experienced the genome size shrinkage observed in long-term endosymbioses and has retained immunogenicity. We focus here on the sixteen antimicrobial peptides (AMPs) identified in the Sitophilus oryzae genome and their expression patterns in different tissues, along host development or upon immune challenges, to address their potential functions in the defensive response and endosymbiosis homeostasis along the insect life cycle.This article is part of the theme issue ‘Sculpting the microbiome: How host factors determine and respond to microbial colonisation’

J. Biol. Chem.

Regulation of integrin affinity and clustering plays a key role in the control of cell adhesion and migration. The protein ICAP-1alpha (integrin cytoplasmic domain-associated protein- 1alpha) binds to the cytoplasmic domain of the beta(1A) integrin and controls cell spreading on fibronectin. Here, we demonstrate that, despite its ability to interact with beta(1A) integrin, ICAP-1alpha is not recruited in focal adhesions, whereas it is colocalized with the integrin at the ruffling edges of the cells. ICAP-1alpha induced a rapid disruption of focal adhesions, which may result from the ability of ICAP- 1alpha to inhibit the association of beta(1A) integrin with talin, which is crucial for the assembly of these structures. ICAP-1alpha-mediated dispersion of beta(1A) integrins is not observed with beta(1D) integrins that do not bind ICAP. This strongly suggests that ICAP-1alpha action depends on a direct interaction between ICAP-1alpha and the cytoplasmic domain of the beta(1) chains. Altogether, these results suggest that ICAP-1alpha plays a key role in cell adhesion by acting as a negative regulator of beta(1) integrin avidity

Disruption of focal adhesions by integrin cytoplasmic domain- associated protein-1 alpha

Regulation of integrin affinity and clustering plays a key role in the control of cell adhesion and migration. The protein ICAP-1alpha (integrin cytoplasmic domain-associated protein- 1alpha) binds to the cytoplasmic domain of the beta(1A) integrin and controls cell spreading on fibronectin. Here, we demonstrate that, despite its ability to interact with beta(1A) integrin, ICAP-1alpha is not recruited in focal adhesions, whereas it is colocalized with the integrin at the ruffling edges of the cells. ICAP-1alpha induced a rapid disruption of focal adhesions, which may result from the ability of ICAP- 1alpha to inhibit the association of beta(1A) integrin with talin, which is crucial for the assembly of these structures. ICAP-1alpha-mediated dispersion of beta(1A) integrins is not observed with beta(1D) integrins that do not bind ICAP. This strongly suggests that ICAP-1alpha action depends on a direct interaction between ICAP-1alpha and the cytoplasmic domain of the beta(1) chains. Altogether, these results suggest that ICAP-1alpha plays a key role in cell adhesion by acting as a negative regulator of beta(1) integrin avidity

The genome sequence of the grape phylloxera provides insights into the evolution, adaptation, and invasion routes of an iconic pest (vol 18, 90, 2020)

An amendment to this paper has been published and can be accessed via the original article