Genome of Rhodnius prolixus , an insect vector of Chagas disease, reveals unique adaptations to hematophagy and parasite infection

Abstract

Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome (∼702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immune-deficiency (IMD)-mediated immune responses were observed, R. prolixus putatively lacks key components of the IMD pathway, suggesting a reorganization of the canonical immune signaling network. Although both Toll and IMD effectors controlled intestinal microbiota, neither affected Trypanosoma cruzi, the causal agent of Chagas disease, implying the existence of evasion or tolerance mechanisms. R. prolixus has experienced an extensive loss of selenoprotein genes, with its repertoire reduced to only two proteins, one of which is a selenocysteine-based glutathione peroxidase, the first found in insects. The genome contained actively transcribed, horizontally transferred genes from Wolbachia sp., which showed evidence of codon use evolution toward the insect use pattern. Comparative protein analyses revealed many lineage-specific expansions and putative gene absences in R. prolixus, including tandem expansions of genes related to chemoreception, feeding, and digestion that possibly contributed to the evolution of a blood-feeding lifestyle. The genome assembly and these associated analyses provide critical information on the physiology and evolution of this important vector species and should be instrumental for the development of innovative disease control methods.

Hemimetabolous genomes reveal molecular basis of termite eusociality

“…Repeat content for the other studied species (Fig. 1) was obtained from the literature [61][62][63][64][65][66][67] .…”

Developmental roles of tyrosine metabolism enzymes in the blood-sucking insect Rhodnius prolixus

“…Using gene information available from genome sequencing [11], RNAi was used to evaluate the effects on the physiology and development of R. prolixus of tyrosine metabolism enzymes. These enzymes either are involved in the production Table 1.…”

“…Recently, its genome has been sequenced [11], which has allowed a systematic study of tyrosine metabolism enzymes. Previously, we showed that the inhibition of either tyrosine aminotransferase (TAT) or 4-hydroxyphenylpyruvate dioxygenase (HPPD)-the first two enzymes of the tyrosine catabolism pathway-causes the death of R. prolixus and other blood-feeding arthropods but is harmless to non-haematophagous insects, revealing an essential role of this pathway in the adaptation to haematophagy by detoxifying excess dietary tyrosine [3].…”

Abbreviations and acronyms

“…LGT of fragments of the Wolbachia genome (total size approximately 1.2 Mb), ranging from 500 base pairs to more than 1 Mb, have been observed in many invertebrates, including beetles (Nikoh et al, 2008), grasshoppers (Funkhouser-Jones, 2015;Toribio-Fernández et al, 2017), wasps (Dunning-Hotopp et al, 2007), fruit flies (Dunning-Hotopp et al, 2007;Klasson et al, 2014;Choi, Bubnell and Aquadro, 2015;Morrow et al, 2015), tsetse flies (Brelsfoard et al, 2014;Nakao et al, 2016), butterflies and moths , kissing bugs (Mesquita et al, 2015), mosquitoes (Klasson et al, 2009;Hou et al, 2014), filarial nematodes (Fenn et al, 2006;Dunning-Hotopp et al, 2007;Keroack et al, 2016) and spiders (Baldo et al, 2008).…”