Séminaire IBIP – école MISTRAL
Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Lundi 9 juillet 2018
à 13h30, amphi 206

In vivo analysis of Ca2+ dynamics in Arabidopsis: tools and applications

Alex Costa
Department of Biosciences, University of Milan, Italy

In plants, increases in cytosolic Ca2+ concentration ([Ca2+]cyt), occurring in response to both biotic and abiotic stimuli, work as a key component of different signal transduction pathways. Depending on the stimulus, Ca2+ rises can display the form of a single transient or repetitive Ca2+ oscillations and are commonly designated as « Ca2+ signatures ». Generation and shaping of Ca2+ signatures depends on fine-tuning of Ca2+ influxes and effluxes occurring at both the plasma membrane (PM) and membranes of the different subcellular compartments. The opening of PM Ca2+-permeable influx channels (e.g. GLRs, CNGCs, OSCAs….) in response to different stimuli will release Ca2+ into the cytosol and cause the generation of a Ca2+ transient, while activity of active Ca2+ efflux transporters (e.g. H+/Ca2+ antiporters, Ca2+ ATPases…) will return the [Ca2+]cyt to resting concentrations. Not only cytosol but also organelles and other subcellular compartments (e.g. chloroplasts, mitochondria, endoplasmic reticulum…) experience Ca2+ transients, hence putatively participate in the cellular Ca2+ homeostasis and potentially in the Ca2+ signature shaping process. To study these processes in planta the use of non-invasive state of the art imaging tools is required. In such a context the seminar will provide an overview of:

• use of the genetically encoded Ca2+ sensors, including ratiometric FRET (Förster Resonance Energy Transfer)-based Ca2+ Cameleon and intensimetric GCaMP sensors. Attention will be paid to the developed Cameleon sensors for the analyses of Ca2+ dynamics in different subcellular compartments;
• use of different microscopy solutions, including Light Sheet Fluorescence Microscopy (LSFM), for FRET-based Ca2+ imaging analyses in Arabidopsis root cells;
• use of the presented technologies for the study of channels and pumps involved in the generation and regulation of cytosolic Ca2+ dynamics.

Contact : Anne-Aliénor Véry