Comparative genomics analysis of triatomines reveals common first line and inducible immunity-related genes and the absence of Imd canonical components among hemimetabolous arthropods

Federico Alonso Zumaya-Estrada,Rolando Rivera-Pomar,Andrés Lavore,Mario Henry Rodríguez,Jesús Martínez-Barnetche

doi:10.1186/s13071-017-2561-2

Abstract

BackgroundInsects operate complex humoral and cellular immune strategies to fend against invading microorganisms. The majority of these have been characterized in Drosophila and other dipterans. Information on hemipterans, including Triatominae vectors of Chagas disease remains incomplete and fractionated.ResultsWe identified putative immune-related homologs of three Triatominae vectors of Chagas disease, Triatoma pallidipennis, T. dimidiata and T. infestans (TTTs), using comparative transcriptomics based on established immune response gene references, in conjunction with the predicted proteomes of Rhodnius prolixus, Cimex lecticularis and Acyrthosiphon pisum hemimetabolous. We present a compressive description of the humoral and cellular innate immune components of these TTTs and extend the immune information of other related hemipterans. Key homologs of the constitutive and induced immunity genes were identified in all the studied hemipterans.ConclusionsOur results in the TTTs extend previous observations in other hemipterans lacking several components of the Imd signaling pathway. Comparison with other hexapods, using published data, revealed that the absence of various Imd canonical components is common in several hemimetabolous species.

Highlights

Insects operate complex humoral and cellular immune strategies to fend against invading microorganisms
Here, using as reference immune molecules described in established invertebrate immunology models [1, 36], we present a compressive description of the humoral and cellular innate immune components of four important Chagas disease vectors (TPAL, T. dimidiata (TDIM), Triatoma infestans (TINF) and Rhodnius prolixus (RPRO)), along with two other hemipterans phylogenetically related (CLEC and Acyrthosiphon pisum (ACPI))
Homologs involved in microbial recognition and immune activation (GNBPs, PGRPs, C-type lectin (CTL), thioester-containing proteins (TEPs), scavenger receptor (SR) and CLIP domain serine proteases (CLIP)) were documented in most species

Summary

Introduction

Insects operate complex humoral and cellular immune strategies to fend against invading microorganisms. The majority of these have been characterized in Drosophila and other dipterans. Arthropods possess complex innate immune mechanisms to fend against viruses, bacteria, fungi and parasites. In Drosophila, PRRs bind to conserved pathogen-associated molecular patterns (PAMPs) [1]. These molecular interactions initiate the immune signal transduction through three main pathways, Toll, JakSTAT and Imd. The immune signaling culminates in the translocation into the nucleus of NF-kB/Rel transcription factors, which activate humoral responses characterized by the synthesis of antimicrobial peptides (AMPs) with broad activity spectrum against bacteria, and fungi [1, 4]

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