A Guard Cell Abscisic Acid (ABA) Network Model That Captures the Stomatal Resting State

Abstract

Stomatal pores play a central role in the control of carbon assimilation and plant water status. The guard cell pair that borders each pore integrates information from environmental and endogenous signals and accordingly swells or deflates, thereby increasing or decreasing the stomatal aperture. Prior research shows that there is a complex cellular network underlying this process. We have previously constructed a signal transduction network and a Boolean dynamic model describing stomatal closure in response to signals including the plant hormone abscisic acid (ABA), calcium or reactive oxygen species (ROS). Here, we improve the Boolean network model such that it captures the biologically expected response of the guard cell in the absence or following the removal of a closure-inducing signal such as ABA or external Ca 2+. The expectation from the biological system is reversibility, i.e., the stomata should reopen after the closing signal is removed. We find that the model's reversibility is obstructed by the previously assumed persistent activity of four nodes. By introducing time-dependent Boolean functions for these nodes, the model recapitulates stomatal reopening following the removal of a signal. The previous version of the model predicts ∼20% closure in the absence of any signal due to uncertainty regarding the initial conditions of multiple network nodes. We systematically test and adjust these initial conditions to find the minimally restrictive combinations that appropriately result in open stomata in the absence of a closure signal. We support these results by an analysis of the successive stabilization of feedback motifs in the network, illuminating the system's dynamic progression toward the open or closed stomata state. This analysis particularly highlights the role of cytosolic calcium oscillations in causing and maintaining stomatal closure. Overall, we illustrate the strength of the Boolean network modeling framework to efficiently capture cellular phenotypes as emergent outcomes of intracellular biological processes.

Optogenetic control of the guard cell membrane potential and stomatal movement by the light-gated anion channel Gt ACR1

“…The impact of the successive activation of K + efflux channels and the H + -ATPase on the GtACR1-induced depolarization was studied with a mathematical model. Models for guard cells responses have been published earlier (48,49), but these models were based on holistic approaches and therefore not suitable for our purpose. We developed the minimal GuardIon model (Fig.…”

Influence of the Rhizobacterium Rhodobacter sphaeroides KE149 and Biochar on Waterlogging Stress Tolerance in Glycine max L.

“…A large number of studies reported that ABA maintains water levels in the cell as it controls stomatal activity [38]. In general, low water retention allows guard cells around stomata to close and, at higher moisture levels, it activates the stomatal conductance and stimulates the transpiration rate [39].…”

Signatures of natural selection in a foundation tree along Mediterranean climatic gradients

“…In addition, the SNP associated with P WQ (JAR13490) was found in the chromatin-remodelling factor PKL gene that has been consistently linked to multiple plant development processes, particularly to the abscisic acid (ABA) pathway regulation (Perruc et al, 2007). ABA is a phytohormone that is well known for controlling stomatal closure (Rajab et al, 2019, Maheshwari et al, 2020, thus being crucial for efficient drought response (Yu et al, 2019, Zhang et al, 2020b. From P MA , one SNP (JAR01263) was found associated with the methionine gamma-lyase (MGL) gene.…”