Silencing the odorant receptor co-receptor RproOrco affects the physiology and behavior of the Chagas disease vector Rhodnius prolixus.
Olfaction is one of the main sensory modalities that allow insects to interpret their environment. Several proteins, including odorant-binding proteins (OBPs) and odorant receptors (ORs), are involved in this process. Odorant receptors are ion channels formed by a binding unit OR and an odorant receptor co-receptor (Orco). The main goal of this study was to characterize the Orco gene of Rhodnius prolixus (RproOrco) and to infer its biological functions using gene silencing. The full-length RproOrco gene sequence was downloaded from VectorBase. This gene has 7 introns and is located in the genome SuperContig GL563069: 1,017,713-1,023,165. RproOrco encodes a protein of 473 amino acids, with predicted 7 transmembrane domains, and is highly expressed in the antennae during all R. prolixus developmental stages. The RNAi technique effectively silenced RproOrco, reducing the gene's expression by approximately 73%. Interestingly, the effect of gene silencing persisted for more than 100 days, indicating a prolonged effect of dsRNA that was maintained even after molting. The phenotypic effects of silencing involved the following: (1) loss of the ability to find a vertebrate host in a timely manner, (2) decreased ingested blood volume, (3) delayed and decreased molt rate, (4) increased mortality rate, and (5) decreased egg laying. Our data strongly suggest that dsOrco disrupts R. prolixus host-finding behavior, which is further reflected in the blood ingestion, molting, mortality, and egg laying data. This study clearly demonstrates that Orco is an excellent target for controlling triatomine populations. Thus, the data presented here open new possibilities for the control of vector-borne diseases.
Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909, Rio de Janeiro, RJ, Brazil.
Thiago A
TA
Franco
Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909, Rio de Janeiro, RJ, Brazil.
Daniele S
DS
Oliveira
Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil.
Monica F
MF
Moreira
Department of Molecular and Cellular Biology, University of California, 95616, Davis, CA, USA.
Walter S
WS
Leal
Universidade Federal do Rio de Janeiro, Instituto de Química, 21941-909, Rio de Janeiro, RJ, Brazil; Department of Molecular and Cellular Biology, University of California, 95616, Davis, CA, USA; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil. Electronic address: anamelo@iq.ufrj.br.
Ana C A
AC
Melo
D000818:Animals; D057506:Arthropod Antennae / Q000502:physiology; D014355:Chagas Disease / Q000635:transmission; D005247:Feeding Behavior; D005260:Female; D020868:Gene Silencing; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics*; D007303:Insect Vectors; D008297:Male; D018978:Molting / Q000502:physiology; D010058:Oviposition / Q000502:physiology; D010802:Phylogeny; D034622:RNA Interference; D012330:RNA, Double-Stranded; D011817:Rabbits; D018035:Receptors, Odorant / Q000235:genetics*; D012239:Rhodnius / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
D019476:Insect Proteins; D012330:RNA, Double-Stranded; D018035:Receptors, Odorant; C045648:odorant-binding protein
Interfering RNA; Odorant co-receptor; Orco; Rhodnius prolixus