An insight into the sialotranscriptome of Triatoma matogrossensis, a kissing bug associated with fogo selvagem in South America

Abstract

Triatoma matogrossensis is a Hemiptera that belongs to the oliveirai complex, a vector of Chagas' disease that feeds on vertebrate blood in all life stages. Hematophagous insects' salivary glands (SGs) produce potent pharmacologic compounds that counteract host hemostasis, including anticlotting, antiplatelet, and vasodilatory molecules. Exposure to T. matogrossensis was also found to be a risk factor associated with the endemic form of the autoimmune skin disease pemphigus foliaceus, which is described in the same regions where Chagas' disease is observed in Brazil. To obtain a further insight into the salivary biochemical and pharmacologic diversity of this kissing bug and to identify possible allergens that might be associated with this autoimmune disease, a cDNA library from its SGs was randomly sequenced. We present the analysis of a set of 2,230 (SG) cDNA sequences, 1,182 of which coded for proteins of a putative secretory nature.

Figure 1.

Phylogram of the salivary inositol phosphatases from bloodsucking Hemiptera. The number at the nodes indicates percentage of bootstrap support above 50% value. Sequences are represented by the first three letters of the genus name followed by the first three letters of the species name, followed by the National Center for Biotechnology Information (NCBI) accession number. The species represented are TRIMAT, Triatoma matogrossensis; TRIINF, Triatoma infestans; TRIDIM, Triatoma dimidiata; CIMLEC, Cimex lectularius; RHOPRO, Rhodnius prolixus. The bar at the bottom indicates 10% amino acid divergence. For other details, see text.

Figure 2.

Phylogram of the salivary lipocalins of Triatoma matogrossensis. Roman numerals indicate clades with robust bootstrapped support. The number at the nodes indicates percentage of bootstrap support above 50% value. The bar at the bottom indicates 50% amino acid divergence. For other details, see text.

Figure 3.

The MYS3/hemolysin family of triatomines. (A) Clustal alignment showing conserved residues. The bar at the top indicates the region of the signal peptide indicative of secretion. The box at the end of the sequences indicates a glycine/serine-rich region found in a subset of the sequences. Sequences are represented by the first three letters of the genus name followed by the first two letters of the species name, followed by the National Center for Biotechnology Information (NCBI) accession number. The symbols below the alignment indicates (*) identity, (:) conserved, and (.) less conserved sites. (B) Consensus bootstrapped phylogenetic tree based on the alignment in A, showing three robust clades of proteins. The numbers at the nodes indicate percentage of bootstrap support. The line at the bottom indicates 20% amino acid diversity.