The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq

Abstract

BackgroundTick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interactions, and transcriptional profiling of salivary glands is a powerful tool to do so. Here, we functionally annotated the sialotranscriptomes of these three Amblyomma species, which allowed comparisons between these and other hematophagous arthropod species.MethodsmRNA from the salivary glands of A. triste, A. cajennense and A. parvum ticks fed on different host species were pyrosequenced on a 454-Roche platform to generate four A. triste (nymphs fed on guinea pigs and females fed on dogs) libraries, one A. cajennense (females fed on rabbits) library and one was A. parvum (females fed on dogs) library. Bioinformatic analyses used in-house programs with a customized pipeline employing standard assembly and alignment algorithms, protein databases and protein servers.ResultsEach library yielded an average of 100,000 reads, which were assembled to obtain contigs of coding sequences (CDSs). The sialotranscriptome analyses of A. triste, A. cajennense and A. parvum ticks produced 11,240, 4,604 and 3,796 CDSs, respectively. These CDSs were classified into over 100 distinct protein families with a wide range of putative functions involved in physiological and blood feeding processes and were catalogued in annotated, hyperlinked spreadsheets. We highlighted the putative transcripts encoding saliva components with critical roles during parasitism, such as anticoagulants, immunosuppressants and anti-inflammatory molecules. The salivary content underwent changes in the abundance and repertoire of many transcripts, which depended on the tick and host species.ConclusionsThe annotated sialotranscriptomes described herein richly expand the biological knowledge of these three Amblyomma species. These comprehensive databases will be useful for the characterization of salivary proteins and can be applied to control ticks and tick-borne diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-3305-7-430) contains supplementary material, which is available to authorized users.

De novo assembly and annotation of the salivary gland transcriptome of Rhipicephalus appendiculatus male and female ticks during blood feeding

“…This was opposed to low levels, of between 3 -28%, observed in the secretory class of the sialotranscriptomes of Amblyomma ticks (Garcia et al, 2014;Karim and Ribeiro, 2015). The mouthparts of the ticks might offer one plausible explanation for the high levels of Glycine rich transcripts in the R. appendiculatus and R. pulchellus sialotranscriptomes, compared to the levels observed in Amblyomma ticks.…”

“…Seventeen percent of the predicted R. appendiculatus proteins were characterised as putative secretory proteins, which was in the same range as other tick sialotranscriptomes of about 13 -37% (Garcia et al, 2014;Karim and Ribeiro, 2015;Karim et al, 2011;Tan et al, 2015a).…”

“…Next generation sequencing, which produces millions of sequencing reads, can achieve the sequence depth required to elucidate even lowly expressed genes of complex protein families. To exploit these advances, a number of de novo sialotranscriptomes (sets of RNA molecules in tick salivary glands) have recently been generated using NGS technologies for a number of tick species; A. maculatum (Karim et al, 2011), Ixodes ricinus (Schwarz et al, 2013), Dermacentor andersoni (Mudenda et al, 2014), A. triste, A. parvum and A. cajennense (Garcia et al, 2014), Haemaphysalis flava (Xu et al, 2015) and R. pulchellus (Tan et al, 2015a). These transcriptomes highlighted the true expansion within salivary protein families in the different tick species and identified new candidate genes involved in feeding.…”

Ancestral reconstruction of tick lineages

“…BLAST analysis using confirmed arthropod PGE2 synthases Yamamoto et al 2013), retrieved a single sequence from I. scapularis (GI: 241751467) (E-value = 10 -93 ). Analysis using this sequence retrieved orthologs (E-value = 10 0 ) from salivary gland transcriptomes of I. ricinus , A. maculatum (Karim et al 2011), A. cajennense and A. parvum (Garcia et al 2014) and R. pulchellus (Tan et al 2015).…”

AeMOPE-1: um novo peptídeo imunomodulador salivar de <i>Aedes aegypti </i>com potencial terapêutico na colite experimental.

“…(3) A molécula AFXa se liga ao fator X ativo e a molécula AaTI se liga à trombina impedindo a coagulação sanguínea. (ANATRIELLO et al, 2010;GARCIA et al, 2014;RIBEIRO et al, 2011;VALENZUELA et al, 2002a). aegypti, a literatura a respeito deste assunto ainda é escassa e pouco se sabe sobre as moléculas responsáveis por tais atividades.…”