Comparative Genomics Provide Insights Into Function and Evolution of Odorant Binding Proteins in Cydia pomonella

Abstract

Insect olfaction is vital for foraging, mating, host-seeking, and avoidance of predators/pathogens. In insects, odorant binding proteins (OBPs) are involved in transporting hydrophobic odor molecules from the external environment to receptor neurons. The codling moth, Cydia pomonella, one of the most destructive insect fruit pests, causes enormous economic losses. However, little is known about the number, variety, gains and losses, and evolution of OBP genes in C. pomonella. Here we report the identification of 40 OBPs in C. pomonella, most (75%) of which are classic OBPs, using genomic and transcriptomic analyses. Two OBP genes were lost in C. pomonella relative to possible distant ancestor in Lepidoptera lineage based on an analysis of gene gains and losses. The phylogenetic tree and chromosome location showed that the expansion of OBP genes mainly resulted from tandem duplications, as the CpomGOBP2 gene was duplicated twice along with loss of CpomPBPB. Two positive selection sites of the CpomGOBP1 gene were identified while other OBP genes evolved under purifying selection. Our results provide fundamental knowledge of OBP genes allowing further study of their function in C. pomonella.

Functional differentiation of two general‐odorant binding proteins in Hyphantria cunea (Drury) (Lepidoptera: Erebidae)

“…In contrast, HcunGOBP1 showed a weak binding affinity, but was consistent (or significant) to all four sex pheromone components (Figs 4 and 5, and Table 1). Similar to previous studies on B. mori , 53 Conopomorpha sinensis , 54 C. pomonella , 55 G. molesta , 56 Heliothis virescens , 57 P. xylostella , 58 and S. littoralis , 59 our results also support the hypothesis that GOBPs might function as an additional selectivity level and may contribute to pheromone discrimination. We suggested that the differential binding affinity in the sex pheromone components might be due to alcohol oxidase which is involved in converting fatty alcohols to pheromone aldehyde analogs 60,61 .…”

Molecular and Functional Characterization of Three General Odorant-Binding Protein 2 Genes in Cydia pomonella (Lepidoptera: Tortricidae)

“…The general odorant-binding proteins have critical functions in the recognition of host plants and mates in lepidopteran insects [15,28]. In previous studies, a total of four general odorant-binding protein genes were characterized in C. pomonella, including one GOBP1 and three duplicates of the GOBP2 gene [24,25]. The three GOBP2 genes were named CpomGOBP2a, CpomGOBP2b, and CpomGOBP2c.…”

“…Studies have confirmed that the copies of CpomOR3 enhanced the capabilities of mate location and host plant recognition. Using genome and transcriptome analysis, scientists determined that the CpomGOBP2 genes have been duplicated twice, named CpomGOBP2a, CpomGOBP2b, and CpomGOBP2c [24,25]. However, the functions of these three CpomGOBP2 genes remained unclear.…”

Antennal transcriptomic analysis of carboxylesterases and glutathione S-transferases associated with odorant degradation in the tea gray geometrid, Ectropis grisescens (Lepidoptera, Geometridae)

“…However, this number was significantly greater than that of CXE genes identified in other species reported, such as C. pomonella (12) ( Huang et al, 2016 ), C. suppressalis (19) ( Liu et al, 2015a ), H. parallela (20) ( Yi et al, 2021 ), and A. lepigone (20) ( Zhang et al, 2017c ). The difference in gene numbers among different species might depend on the evolution of divergent behaviors in the long term, which resulted in gene duplication and loss ( Zhang et al, 2017b ; Huang et al, 2021 ). In addition, the sample preparation and sequencing method/depth might also be a reason.…”