The pharyngeal taste organ of a blood-feeding insect functions in food recognition

ISABEL ORTEGA; LATORRE ESTIVALIS, JOSE MANUEL; ANDRE LUIS COSTA-DA-SILVA; AGUSTINA CANO; TERESITA C. INSAUSTI; HÉCTOR SALAS MORALES; GINA PONTES; MARTÍN BERÓN DE ASTRADA,; SHEILA ONS; MATTHEW DEGENNARO ; ROMINA B. BARROZO

BMC BIOLOGY

BIOMED CENTRAL LTD

Año: 2024 vol. 22

1741-7007

Background Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survivalfrom the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingestedfood. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissingbug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, com‑prises eight taste sensilla that become bathed with the incoming blood.Results We showed that these taste sensilla house gustatory receptor neurons projecting their axonsthrough the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electricallyactivated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP, and cafeine. Using RNA-Seq, weexamined the expression of sensory-related gene families in the PO. We identifed gustatory receptors, ionotropicreceptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors,neuropeptide receptors, and biogenic amine receptors. RNA interference assays demonstrated that the salt-relatedpickpocket channel Rproppk014276 is required during feeding of an appetitive solution of NaCl and ATP.Conclusions We provide evidence of the role of the pharyngeal organ in food evaluation. This work shows a compre‑hensive characterization of a pharyngeal taste organ in a hematophagous insect.