Systems Dynamic Modeling of a Guard Cell Cl- Channel Mutant Uncovers an Emergent Homeostatic Network Regulating Stomatal Transpiration

作者：Wang Yizhou; Papanatsiou Maria; Eisenach Cornelia; Karnik Rucha; Williams Mary; Hills Adrian; Lew Virgilio L; Blatt Michael R^*

来源：Plant Physiology, 2012, 160(4): 1956-1967.

DOI：10.1104/pp.112.207704

Stomata account for much of the 70% of global water usage associated with agriculture and have a profound impact on the water and carbon cycles of the world. Stomata have long been modeled mathematically, but until now, no systems analysis of a plant cell has yielded detail sufficient to guide phenotypic and mutational analysis. Here, we demonstrate the predictive power of a systems dynamic model in Arabidopsis (Arabidopsis thaliana) to explain the paradoxical suppression of channels that facilitate K+ uptake, slowing stomatal opening, by mutation of the SLAC1 anion channel, which mediates solute loss for closure. The model showed how anion accumulation in the mutant suppressed the H+ load on the cytosol and promoted Ca2+ influx to elevate cytosolic pH (pH(i)) and free cytosolic Ca2+ concentration ([Ca2+](i)), in turn regulating the K+ channels. We have confirmed these predictions, measuring pH(i) and [Ca2+](i) in vivo, and report that experimental manipulation of pHi and [Ca2+] i is sufficient to recover K+ channel activities and accelerate stomatal opening in the slac1 mutant. Thus, we uncover a previously unrecognized signaling network that ameliorates the effects of the slac1 mutant on transpiration by regulating the K+ channels. Additionally, these findings underscore the importance of H+-coupled anion transport for pH(i) homeostasis.

• 出版日期2012-12