Integrative Plant Physiology
Bacsik, Mary , Durham, Tessa , Spalding, Edgar .
Investigating Roles for Glutamate Receptor-Like Genes in Growth Responses to Root Crowding.
The Glutamate Receptor-Like (GLR) gene family of Arabidopsis shares homology with the channel-forming glutamate receptors of mammals (iGluRs). At least one member of the family (GLR3.3) is required for normal membrane depolarization and intracellular calcium rises in response to six "potent" amino acids (glutamate, alanine, asparagine, cysteine, glycine, and serine) in roots in a manner similar to what has been described in mammalian systems. One major challenge is to link the GLR-mediated ionic processes to physiological or developmental processes in plants. Root exudates are known to contain the above amino acids at concentrations high enough to activate GLR-dependent electrical responses. Using mutants with disruptions in specific GLR genes, this study explores the hypothesis that GLRs play a role in responding to signals released by other roots. The assay being employed is one in which roots of plants sown at different densities are forced to grow through an increasingly constricted agar-filled path. At high densities, growth of wild-type roots is inhibited compared to growth at low densities. Preliminary results have shown that root growth of glr3.3 mutants is less inhibited than wild-type when grown in a crowded environment. Confirming this effect in independent glr3.3 alleles and extending the study to other GLR family members could link the ionic responses to amino acids to an adaptive developmental process and thereby explain the presence of neurotransmitter-gated receptors in plants.
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1 - University of Wisconsin-Madison, Botany, 430 Lincoln Dr., Madison, WI, 53706, U.S.A.
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM