Small Pores with a Big Impact

This Focus Issue on Stomata is the first dedicated to the evolution, development, and physiology of guard cells, their fundamental relevance to plants and to society. Several reviews and articles in this Focus Issue center around stomata as a target for genetic engineering to improve water use efficiency and their importance for crop survival. The Update reviews of Vialet-Chabrand et al. (2017b) and Matthews et al. (2017) address the potential for improved water use efficiencies by enhancing the kinetics of guard cell responses to environmental cues relevant for photo- synthesis. Hughes et al. (2017) demonstrate the efficacy of manipulating stomatal densities to enhance water use efficiency and drought tolerance, while Hochberg et al. (2017) highlight the interplay between stomatal function, water delivery to the leaf, and leaf shedding in the field.