IDENTIFICATION AND CHARACTERIZATION OF TWO SENSORY NEURON MEMBRANE PROTEINS FROM Cnaphalocrocis medinalis (LEPIDOPTERA: PYRALIDAE)

Abstract

Sensory neuron membrane proteins (SNMPs), which are located on the dendritic membrane of olfactory neurons, were considered as important components involved in pheromone reception in insects. In Drosophila melanogaster, mutants without SNMP are unable to evoke neuronal activities in the presence of pheromone cis-vaccenyl acetate (cVA). So deeply understanding the SNMPs functions may help to develop pheromone-mediated insect pest management tactics. The present study reports the identification and characterization of CmedSNMP1 and CmedSNMP2, two candidate SNMPs in the rice leaffolder, Cnaphalocrocis medinalis, one of the serious rice insect pests in Asia. The comparison of amino acid sequences shows that CmedSNMP1 and CmedSNMP2 are very similar to the previously reported SNMPs isolated from moths such as Ostrinia nubilalis and O. furnacalis, respectively, but the two CmedSNMPs share low identity with each other. The distribution patterns of two CmedSNMPs in different tissues of adult moths were examined using RT-PCR and quantitative real-time PCR. Although the two genes are expressed not only in antennae but also in nonolfactory tissues such as wings, legs, and body; the relative transcription level shows both CmedSNMP1 and CmedSNMP2 are highly enriched in antennae. The dN/dS ratios of the two CmedSNMPs indicate that the two genes are all subject to purifying selection and evolved to be functional genes. This work presents for the first time a study on the SNMPs of C. medinalis, which may help in providing guidance to future functional research of moth SNMPs.

Identification and localization of two sensory neuron membrane proteins from Spodoptera litura (Lepidoptera: Noctuidae)

“…Amino acid sequence comparison shows that SlituSNMP1 and SlituSNMP2 have all the characteristics of SNMPs, especially two transmembrane domains, as well as six conserved cysteines suggested to form disulfide bridge in the large central extracellular loop (Rasmussen et al ., ). Phylogenetic analysis indicates that the insect SNMPs, which are structurally different from odorant receptors (Krieger et al ., ; Krieger et al ., ; Nakagawa et al ., ; Wang et al ., ), are divided into two clear subgroups, SNMP1 and SNMP2, similar to previous reports (Nichols & Vogt, ; Vogt et al ., ; Liu et al ., ; Liu et al ., ). Furthermore, in each of the two subgroups, the SNMPs from different Lepidoptera species cluster together, forming a clade distinct from SNMP homologues of Coleoptera, Diptera and Hymenoptera.…”

“…A similar expression pattern was also found for ApolSNMP1 and ApolSNMP2 on the antennae of male Antheraea polyphemus (Forstner et al ., ). Recently the SNMPs in Cnaphalocrocis medinalis , Agrotis ipsilon and S. exigua have been identified and discussed (Liu et al ., ; Gu et al ., ; Liu et al ., ). The exact function of SNMPs in moths is still unknown, but the essential role in pheromone reception in D. melanogaster and the broad expression in pheromone sensing sensilla indicate they may be involved in pheromone detection in Lepidoptera.…”

Pheromone Reception in Moths

“…Since then, much progress has been achieved in the identification of SNMP1 and SNMP2 in different insect orders. 103,119,[126][127][128][129][130][131][132][133] ApolSNMP1 mRNA expression increased significantly 1-2 days before adult emergence, coinciding with the functional maturation of the olfactory system. The abundant expression of SNMP1 in pheromonespecific olfactory neurons suggests it may be involved in pheromone detection.…”

“…136,137 This was the first demonstration of SNMP functions in vivo. Additionally, it has been reported that SNMPs display wide expression patterns in different tissues, [129][130][131][132][133] suggesting that they may be involved in some functions beyond olfactory detection.…”

Expression patterns and colocalization of two sensory neurone membrane proteins in Ectropis obliqua Prout, a geometrid moth pest that uses Type‐II sex pheromones

“…Two SNMP subfamilies, SNMP1 and SNMP2, have been identified in insects (Nichols & Vogt, 2008); in addition, a novel lepidopteran SNMP, SNMP3, has recently been characterized (Zhang et al, 2018). Since then, diverse SNMP1 and SNMP2 homologues have been identified across insect species (Li & Qin, 2011;Liu et al, 2012;Xiao et al, 2017). Since then, diverse SNMP1 and SNMP2 homologues have been identified across insect species (Li & Qin, 2011;Liu et al, 2012;Xiao et al, 2017).…”