title: Heterologous Expression and Functional Analysis of Rice GLUTAMATE RECEPTOR-LIKE Family Indicates its Role in Glutamate Triggered Calcium Flux in Rice Roots.
abstract: BACKGROUND
  Tremendous progress has been made in understanding the functions of the GLUTAMATE RECEPTOR-LIKE (GLR) family in Arabidopsis. Still, the functions of OsGLRs in rice, especially the ion channel activities, are largely unknown.
  
  
  RESULTS
  Using the aequorin-based luminescence imaging system, we screened the specificity of amino acids involved in the induction of Ca(2+) flux in rice roots. Of all the amino acids tested, glutamate (Glu) was the only one to trigger Ca(2+) flux significantly in rice roots. Detailed analysis showed a dose response of Ca(2+) increase to different concentrations of Glu. In addition, the Ca(2+) spike response to Glu was rapid, within 20 s after the application. A desensitization assay and pharmacological tests showed that the Glu-triggered Ca(2+) flux is mediated by OsGLRs. Whole genome analysis identified 13 OsGLR genes in rice, and these genes have various expression patterns in different tissues. Subcellular localization studies showed that all the OsGLRs examined are likely localized to the plasma membrane. Bacteria growth assays showed that at least OsGLR2.1 and OsGLR3.2 have the potential to mediate ion uptake in bacteria. Further analysis using Fura-2-based Ca(2+) imaging revealed a Glu-triggered Ca(2+) increase in OsGLR2.1-expressing human embryonic kidney (HEK) cells.
  
  
  CONCLUSIONS
  Our work provides a molecular basis for investigating mechanisms of Glu-triggered Ca(2+) flux in rice.
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China. nijun@hznu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ni
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of Biochemistry, Hainan Medical College, Haikou, 571199, China.
authors.forename: Guankui
authors.initials: G
authors.lastname: Du
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, CV4 7AL, UK.
authors.forename: Jemma L
authors.initials: JL
authors.lastname: Taylor
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China.
authors.forename: Chenjia
authors.initials: C
authors.lastname: Shen
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310018, China.
authors.forename: Xunyan
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 311400, China.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Yunrong
authors.initials: Y
authors.lastname: Wu
keywords: Aequorin; Calcium; GLR; Glu; HEK cells; Rice