Taste coding of heavy metal ion-induced avoidance in Drosophila
Xiaonan Li,
Yuanjie Sun,
Shan Gao,
Yan Li,
Li Liu,
Yan Zhu
Affiliations
Xiaonan Li
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yuanjie Sun
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Shan Gao
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yan Li
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Li Liu
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yan Zhu
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China; Corresponding author
Summary: Increasing pollution of heavy metals poses great risks to animals globally. Their survival likely relies on an ability to detect and avoid harmful heavy metal ions (HMIs). Currently, little is known about the neural mechanisms of HMI detection. Here, we show that Drosophila and related species of Drosophilidae actively avoid toxic HMIs at micromolar concentrations. The high sensitivity to HMIs is biologically relevant. Particularly, their sensitivity to cadmium is as high as that to the most bitter substance, denatonium. Detection of HMIs in food requires Gr66a+ gustatory neurons but is independent of bitter-taste receptors. In these neurons, the ionotropic receptors IR76b, IR25a, and IR7a are required for the perception of heavy metals. Furthermore, IR47a mediates the activation of a distinct group of non-Gr66a+ gustatory neurons elicited by HMIs. Together, our findings reveal a surprising taste quality represented by noxious metal ions.