Involved or not involved - the role of the glutamate receptor 2.5 gene in root development under stress

Abstract

Anthropogenic activities have become a worldwide problem as they have led to environmental contamination, which is not biodegradable and persistent. The contamination causes and effect on plant roots and because plants lack mobility, they possess high plasticity in root development. Research showed that amino acids and metals induce the same morphogenic response: primary root growth inhibition and lateral root growth. But which genes are involved is still not clear. This research investigates a gene for primary root growth inhibition: the AtGLR2.5 gene, belonging to the family of glutamate receptor-like proteins. This gene has four splicing variants: AtGLR2.5a, AtGLR2.5b, AtGLR2.5c and AtGLR2.5d and unpublished data showed that transformation of a glr2.5 mutant with the AtGLR2.5c cDNA can restore L-glutamate sensitivity. The first hypothesis states that AtGLR2.5c could be involved in the impairment of the primary root growth under L-glutamate stress, and a second hypothesis states its involvement in metal-induced primary root inhibition. The results of this research project indicated a primary root growth inhibition under the L-glutamate, copper, cadmium and zinc treatments. The gene expression of the splicing variant AtGLR2.5c was also measured under the different treatments. Analysing the data showed that the splicing variant AtGLR2.5c was not involved in the primary root growth under L-glutamate stress, but it was involved in the primary root growth under metal stress.