Characterization of the pheromone receptors in Mythimna loreyi reveals the differentiation of sex pheromone recognition in Mythimna species

Pheromone receptors(PRs)are key proteins in the molecular mechanism of pheromone recognition,and exploring the functional differentiation of PRs between closely related species helps to understand the evolution of moth mating systems.Pheromone components of the agricultural pest Mythimna loreyi have turned into(Z)-9-tetradecen-1-yl acetate(Z9-14:OAc),(Z)-7-dodecen-1-yl acetate(Z7-12:OAc),and(Z)-11-hexadecen-1-yl acetate,while the composition differs from that of M.separata in the genus Mythimna.To understand the molecular mechanism of pheromone recognition,we sequenced and analyzed antennal transcriptomes to identify 62 odorant receptor(OR)genes.The expression levels of all putative ORs were analyzed using differentially expressed gene analysis.Six candidate PRs were quantified and functionally characterized in the Xenopus oocytes system.MlorPR6 and MlorPR3 were determined to be the receptors of major and minor components Z9-14:OAc and Z7-12:OAc.MlorPR1 and female antennae(FA)-biased MlorPR5 both possessed the ability to detect pheromones of sympatric species,including(Z,E)-9,12-tetradecadien-1-ol,(Z)-9-tetradecen-1-ol,and(Z)-9-tetradecenal.Based on the comparison of PR functions between M.loreyi and M.separata,we analyzed the differentiation of pheromone recognition mechanisms during the evolution of the mating systems of 2 Mythimna species.

Functional characterization of pheromone receptor candidates in codling moth Cydia pomonella(Lepidoptera:Tortricidae)

Sex pheromones serve a critical role in Lepidopterans finding mates.Male moths perceive and react to sex pheromones emitted by conspecific females through a delicate pheromone communication system.Pheromone receptors(PRs)are the key sensory elements at the beginning of that process.The codling moth(Cydia ponwonella)is an important pome fruit pest globally and a serious invasive species in China.Pheromonebased techniques have been used successfully in monitoring and controlling this species.We conducted ribonucleic acid sequencing analysis of the codling moth antennal transcriptome and identified 66 odorant receptors(ORs)in a population from Xinjiang province,China,of which 14 were PRs,including two novel PRs(CpomOR2e and CpomOR73).Four PRs that contain full-length open reading frames(CpomORl,OR2a,OR5,OR7)and four PRs with ligands that have not been reported previously(CpomORl,OR2a,OR5,OR7)were selected to deorphanize in the heterologous Xenopus oocyte expression system.Specifically,we found that CpomOR2a and CpomOR5 responded to(£,£)-8,10-dodecadien-l-yl acetate(codlemone acetate).Furthermore,CpomOR5(EC50=1.379 x 10-8 mol/L)was much more sensitive to codlemone acetate than CpomOR2a(EC50=1.663×10^(-6) mol/L).Since codlemone acetate is an important component of C.pomonella sex pheromone,our results improve the current understanding of pheromone communication in codling moths and will be helpful for the development of pest management strategies.