Characterizing expression of candidate genes of a glutamate receptor pathway in Arabidopsis thaliana using real-time RT-PCR

The Arabidopsis thaliana genome contains twenty genes that are analogous to mammalian ionotropic glutamate receptors. There are sixteen mammalian glutamate receptors, which are best known for their roles in neuroplasticity, learning, and memory. The large number of glutamate receptors in A. thaliana suggests they play important roles in the plant’s growth and development, possibly serving to regulate function like they do in non-excitable mammalian tissues. A specific glutamate receptor, GLR3.3, is highly expressed in root tissue of plants, and has been found to promote stronger, more coordinated curvature development during the process of gravitropism. Gravitropism is the ability of a plant to change its orientation to that of the gravity vector when displaced from its gravitational set point angle (GSPA). A previous association study identified six candidate genes which were correlated with the same phenotypic characteristics of gravitropism as GLR3.3. Utilizing real time RT-PCR (qRT-PCR) expression profiles were created for each candidate gene, including GLR3.3. A qRT-PCR method was developed to provide a more quantitative and sensitive way for measuring gene expression than traditional PCR methods. Furthermore, MIQE (Minimum Information for Publication of Quantitative Real-Time PCR Experiments) guidelines were followed to ensure data robustness. Expression profiles that were similar to GLR3.3 were hypothesized to be good candidates as cell signaling components of this novel pathway. This is the beginning of a process that will identify a GLR-dependent pathway, the role of this novel pathway in the gravitropic response, and the influence of GLRs in plant physiology.