Gustatory receptor 28b is necessary for avoiding saponin in Drosophila melanogaster. (8th January 2019)

• Record Type: Journal Article
• Authors: Sang, Jiun; Rimal, Suman; Lee, Youngseok
• Is Part Of: EMBO reports. Volume 20:Number 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-01-08
• Subjects: aversive behavior -- electrophysiology -- GR28b (C) -- insecticide; Molecular biology -- Periodicals; Molecular Biology -- Periodicals; Molecular biology; Periodicals; 572.8
• DOI: 10.15252/embr.201847328
• Languages: English
• ISSNs: 1469-221X

Abstract

Abstract: Saponins function as a natural self‐defense mechanism for plants to deter various insects due to their unpleasant taste and their toxicity. Here, we provide evidence that saponin from Quillaja saponaria functions as an antifeedant as well as an insecticide to ward off insects in both the larval and the adult stages. Using a behavioral screen of 26 mutant fly lines, we show that the Gr28b gene cluster plays a role in saponin avoidance in the labellum. The Gr28b mutant does not avoid saponin and exhibits increased lethality when fed saponin‐mixed food. Tissue‐specific rescue experiments with five different Gr28b isoforms revealed that only the Gr28b.c isoform is required for saponin sensation. We propose that in contrast to sensing many other bitter compounds, saponin sensing does not require the function of core taste receptors, such as GR32a, GR33a, and GR66a. Our results reveal a novel role for GR28b in taste. In addition, the ability of saponin to act as insecticides as well as antifeedants suggests its potential application in controlling insect pests. Synopsis: This study reveals that the Gr28b.c isoform expressed in the Drosophila labellum is necessary to detect a saponin extracted from Quillaja saponaria . The Gr28b gene cluster plays a role in saponin avoidance in the labellum. Saponin sensing does not require the function of core receptors such as GR32a, GR33a, and GR66a. Only the Gr28b.c isoform is required for saponin sensation. Abstract : This study reveals that the Gr28b.c isoform expressed in the Drosophila labellum is necessary to detect a saponin extracted from Quillaja saponaria .