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

Mardi 3 juillet 2018
à 10h45, Amphi 2 (Bâtiment 2 Bis)

Quantitative systems modelling of across scales from molecules to the field

Mike Blatt
Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, UK

Stomatal movements depend on the transport and metabolism of osmotic solutes that drive water flux, reversible changes in guard cell volume and turgor. Much detail is known of the these molecular mechanisms, notably in relation to hormone-evoked stomatal movements and the water-stress signal abscisic acid (ABA). By contrast, the mechanism behind stomatal responses to atmospheric humidity has proven highly controversial, with mechanistic arguments dividing between so-called hydropassive and hydroactive processes and whether or not ABA is requisite. To address these, and related issues, my laboratory recently introduced a quantitative systems platform, OnGuard2, with which to explore the mechanisms of stomatal transpiration and response to atmospheric humidity. OnGuard2 utilizes the molecular mechanics of ion transport, metabolism and signalling of the guard cell to define the water relations and transpiration of the leaf. I will demonstrate how OnGuard2 faithfully reproduces the kinetics of stomatal conductance in Arabidopsis, its dependence on VPD and on water feed to the leaf, deriving real predictions which we have verified experimentally. Further developments, currently underway, introduce CO2 and photosynthetic carbon fixation within this framework. These developments bridge the gap between microscale models of guard cell transport and macroscale models of whole-plant transpiration and photosynthetic carbon demand. They also show that OnGuard2 successfully embraces hydropassive and hydroactive processes within a single, overarching mechanistic framework.

Contact : Anne-Aliénor Véry