Date: 12th February 2025
Time: 13:00
Title: Long-distance turgor pressure changes induce local activation of plant glutamate receptor-like channels
Location: Lecture room 228, Lab building, Koetilantie 5
Host: Maija Sierla
Abstract: Calcium (Ca2+) signaling is a fundamental process that influences a wide range of physiological activities in plants, operating at cellular, organ, and whole-plant levels. A comprehensive understanding of these signaling mechanisms is vital for decoding the complexities of plant development and their responses to various biotic and abiotic stresses. In Arabidopsis thaliana, the plant glutamate receptor-like channels (GLRs) family consists of 20 isoforms categorized into three clades. Recent research has illuminated their essential role in mediating long-distance electric and Ca2+ signaling. This, in turn, is crucial for the synthesis of jasmonic acid (JA) and the subsequent activation of JA-dependent signaling pathways, which are key to the plant's adaptation to stress. While the physiological significance of GLRs is increasingly recognized, the activation mechanisms of these channels and the specific physiological roles of their amino acid binding remain largely unexplored. This seminar will focus on the role of AtGLR3.3 in Arabidopsis thaliana, particularly in response to local wounding, leaf injury, and osmotic stress. It will reveal that the in vivo activation of the AtGLR3.3 channel and the subsequent systemic responses require a functional ligand-binding domain for the binding of exogenous amino acids. Utilizing an integrated approach combining imaging and genetic analysis, I will show that mechanical injuries to leaves, such as wounds and burns, as well as hypo-osmotic stress in root cells, lead to a systemic increase in apoplastic L-Glutamate. This increase occurs upstream of AtGLR3.3 activation and is essential for the elevation of cytosolic Ca2+ levels. Moreover, I will also present unpublished data which support the unreported role of long-distance Ca2+ signals in plant acclimation to water availability and regulation of stomatal aperture.
Alex has dedicated himself to studying plant physiological responses, focusing on the mechanisms of stress signaling by creating his own research niche. His research has particularly emphasized the role of Ca2+ signaling in response to environmental stimuli. Moving forward, he aims to expand this work by exploring how these signaling pathways can be manipulated to enhance plant resilience against climate change.