AUTHOR=Chen Hong-Hao , Dewer Youssef , Wang Yan , Tan Shu-Qian , Liu Xiao-Li , Shi Wang-Peng 

TITLE=Interference with orco gene expression affects host recognition in Diorhabda tarsalis

JOURNAL=Frontiers in Physiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.1069391

DOI=10.3389/fphys.2022.1069391

ISSN=1664-042X

ABSTRACT=<p><bold>Introduction:</bold><italic>Diorhabda tarsalis</italic> Weise is an important insect pest of the Chinese licorice <italic>Glycyrrhiza uralensis</italic> Fisch. Behavior of the beetle, including host location, oviposition site selection, self-defense, and aggregation, were regulated by plant volatiles or insect pheromones.</p><p><bold>Aim:</bold> In this study, Identification of ORs and function research on orco were carried out, these could lead to the development of understand for olfaction mechanism in <italic>D. tarsalis</italic>.</p><p><bold>Methods:</bold> ORs were identified by PacBio RS II platform to sequence the antennas of adult <italic>D. tarsalis</italic>, the function of orco was explored by dsRNA interference.</p><p><bold>Results:</bold> 29 odorant receptor candidate genes of <italic>D. tarsalis</italic> were obtained, which code for 130–479 amino acids. Phylogenetic trees of olfactory receptors were constructed with 243 ORs from eight Coleoptera species. <italic>DtarORco</italic>, <italic>DtarOR7</italic> and <italic>DtarOR26</italic> are specifically expressed in the antenna, and the expression levels were significantly higher than other <italic>Dtar</italic>ORs in antenna, there were no differential expression between male and female beetles. An odorant coreceptor gene (<italic>DtarORco</italic>) has characteristics of an odorant receptor family member, the encoded mature protein has a predicted molecular weight of 53.898 kDa, dsRNA L4440 expression vectors were constructed and successfully transformed into ribonuclease III-deficient Escherichia coli strain HT115 DE3. After interference treatment, the relative expression level of <italic>DtarORco</italic> in <italic>D. tarsalis</italic> antennae significantly decreased and electrophysiological responses to host localization odor signals significantly decreased. At the same time, beetles lost the ability to locate hosts.</p><p><bold>Discussion:</bold> The research on its mechanism of olfaction may lead to the development of new control measures that are environmentally friendly.</p>