Food recognition in a blood-feeding insect: characterization of the pharyngeal taste organ

ISABEL ORTEGA-INSAURRALDE; JOSÉ MANUEL LATORRE-ESTIVALIS; SHEILA ONS; MARTIN BERÓN DE ASTRADA; BARROZO, ROMINA B.

BMC BIOLOGY

BIOMED CENTRAL LTD

Lugar: Londres; Año: 2024

1741-7007

Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survival from the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingested food. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissing bug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, comprises 8 taste sensilla that become bathed with the incoming blood. We found (es un resultado actual, no?)that these taste sensilla house gustatory receptor neurons projecting their axons through the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electrically activated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP and caffeine. Using RNA-Seq, we examined the expression of sensory-related gene families in the PO. We identified gustatory receptors, ionotropic receptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors, neuropeptide receptors and biogenic amine receptors. We demonstrated, using RNA interference, that the pickpocket channel Rproppk014276 is necessary for salt detection during feeding, proving the role of the pharyngeal organ in food evaluation. This work provides the first comprehensive characterization of a pharyngeal taste organ in a hematophagous insect.