ABA signaling in guard cells

Abstract

Abstract Stomata are tiny pores on the leaf surface of higher plants surrounded by a pair of guard cells. They are the main gateways for CO2 uptake for photosynthesis and water loss via transpiration, as wall as pathogen invasion. The opening and closing of the stomatal aperture is regulated by a combination of both endogenous signals and environmental factors. Over the last few decades, the guard cell has become a model cell for the study of signaling networks in plants due to the development and the combination of multidisciplinary approaches including molecular and cellular biology, genetics, electrophysiology, biochemistry and whole plant physiology. Numerous studies have demonstrated that ABA levels in guard cells are controlled through the coordinated regulation of ABA biosynthesis, catabolism and transport. In addition, major advances have been made in the understanding of ABA signaling including the identification of soluble ABA receptors, the elucidation of a core ABA signaling pathway and its targets, and the role of second messengers. In this chapter, recent progresses in the current knowledge of ABA signaling network in guard cell are reviewed, in relation to stomatal responses to abiotic and biotic stresses.