Two odorant receptors regulate 1-octen-3-ol induced oviposition behavior in the oriental fruit fly

Abstract

The oriental fruit fly Bactrocera dorsalis (Hendel) is a notorious pest of fruit crops. Gravid females locate suitable oviposition sites by detecting host plant volatiles. Here, we demonstrate that 1-octen-3-ol, a volatile from mango, guides the oviposition behavior of female flies. Two odorant receptors (BdorOR7a-6 and BdorOR13a) are identified as key receptors for 1-octen-3-ol perception by qPCR analysis, heterologous expression in Xenopus laevis oocytes and HEK 293 cells followed by in vitro binding assays, as well as CRISPR/Cas9 genome editing in B. dorsalis. Molecular docking and site-directed mutagenesis are used to determine major binding sites for 1-octen-3-ol. Our results demonstrate the potential of 1-octen-3-ol to attract gravid females and molecular mechanism of its perception in B. dorsalis. BdorOR7a-6 and BdorOR13a can therefore be used as molecular targets for the development of female attractants. Furthermore, our site-directed mutagenesis data will facilitate the chemical engineering of 1-octen-3-ol to generate more efficient attractants.

Loss of Binding Capabilities in an Ecologically Important Odorant Receptor of the Fall Armyworm, Spodoptera frugiperda, by a Single Point Mutation

“…Although cells expressing SfruOR14 Phe79Ala and SfruOR14 Leu202Ala mutants retained their ability to bind PAA, their binding affinities were found to be much higher, suggesting that the compact structure of the binding site may have been relaxed. Similar results were found in Bactrocera dorsalis, 47 Ostrinia f urnacalis, 46 and Anopheles gambiae. 49 Our findings showed that the replacement of a single amino acid can alter the conformation of ORs, and the His83 residue of SfruOR14 is an absolute requirement for PAA binding.…”

“…Similarly, in the fruit fly Bactrocera dorsalis, mutant versions of BborOR13a (Asp320Ala and Lys323Ala) are unable to bind to 1-octen-3-ol. 47 Experimental evidences support the potential role of predicted hydrogen bonding between ipsenol and Tyr84 of ItypOR46 in Ips typogtraphus. When Tyr84 is mutated to Ala, the response of ItypOR46 to ipsenol is completely suppressed.…”

A Faboideae-Specific Floral Scent Betrays Seeds to an Important Granivore Pest

“…Accordingly, 1-octen-3-ol has also been shown to function as a toxin to insect herbivores and pathogens. , Yet, while 1-octen-3-ol has been shown to be involved in plant indirect defenses, acting as alert signal emitted by plants for attracting natural enemies of the herbivores, , herbivores on reproductive organs may use this compound to locate food. For example, a recent paper found that the 1-octen-3-ol emitted from mango fruit attracted the oriental fruit fly Bactrocera dorsalis (Hendel) . Here, we show that R.…”

“…The compound has also been found in other microorganisms such as cyanobacteria and some plant species, including bryophytes . In angiosperms, the compound has been widely discovered in Faboideae, mainly when they are induced by biotic damage, including soybean, cowpea, common bean, lima bean, red clover, and Lotus japonicas. ,− It is often found in reproductive organs such as flowers and fruits of legume species and of other families. − Therefore, we confirm that 1-octen-3-ol is abundantly distributed within the plant kingdom and also commonly found in the subfamily Faboideae.…”

“…For example, a recent paper found that the 1-octen-3-ol emitted from mango fruit attracted the oriental fruit fly Bactrocera dorsalis (Hendel). 43 Here, we show that R. pedestris uses this same compound to locate flowers ready to be inoculated. R. pedestris not only feed on legume seeds but also damage fruits and seeds of other families.…”