Nitric oxide in guard cells as an important secondary messenger during stomatal closure

Abstract

The modulation of guard cell function is the basis of stomatal closure, essential for optimizing water use and CO2 uptake by leaves. Nitric oxide (NO) in guard cells plays a very important role as a secondary messenger during stomatal closure induced by effectors, including hormones. For example, exposure to abscisic acid (ABA) triggers a marked increase in NO of guard cells, well before stomatal closure. In guard cells of multiple species, like Arabidopsis, Vicia and pea, exposure to ABA or methyl jasmonate or even microbial elicitors (e.g., chitosan) induces production of NO as well as reactive oxygen species (ROS). The role of NO in stomatal closure has been confirmed by using NO donors (e.g., SNP) and NO scavengers (like cPTIO) and inhibitors of NOS (L-NAME) or NR (tungstate). Two enzymes: a L-NAME-sensitive, nitric oxide synthase (NOS)-like enzyme and a tungstate-sensitive nitrate reductase (NR), can mediate ABA-induced NO rise in guard cells. However, the existence of true NOS in plant tissues and its role in guard cell NO-production are still a matter of intense debate. Guard cell signal transduction leading to stomatal closure involves the participation of several components, besides NO, such as cytosolic pH, ROS, free Ca2+, and phospholipids. Use of fluorescent dyes has revealed that the rise in NO of guard cells occurs after the increase in cytoplasmic pH and ROS. The rise in NO causes an elevation in cytosolic free Ca2+ and promotes the efflux of cations as well as anions from guard cells. Stomatal guard cells have become a model system to study the signaling cascade mechanisms in plants, particularly with NO as a dominant component. The interrelationships and interactions of NO with cytosolic pH, ROS, and free Ca2+ are quite complex and need further detailed examination. While assessing critically the available literature, the present review projects possible areas of further work related to NO-action in stomatal guard cells.

CASEIN KINASE1-LIKE PROTEIN2 Regulates Actin Filament Stability and Stomatal Closure via Phosphorylation of Actin Depolymerizing Factor

“…To cope with changes in environmental conditions, such as light, temperature, humidity, CO 2 , and salt in soil, plants must tightly regulate the opening and closing of stomata (Roelfsema and Hedrich, 2005;Vavasseur and Raghavendra, 2005;Israelsson et al, 2006). Many cellular signals (e.g., abscisic acid [ABA], H 2 O 2 , Ca 2+ , CO 2 , and NO) regulate stomata by influencing the activities of H + , K + , Ca 2+ , and anion transporters and channels (Pei et al, 2000;Schroeder et al, 2001;Hosy et al, 2003;Desikan et al, 2004;Hirayama and Shinozaki, 2007;Wang and Song, 2008;Gayatri et al, 2013;Kollist et al, 2014). Actin filament reorganization occurs during stomatal closure.…”

Peroxisomal NADP-isocitrate dehydrogenase is required for Arabidopsis stomatal movement

“…On the other hand, nitric oxide (NO) can be generated either by nitrate reductase (NR) or by a peroxisomal nitric oxide synthase (NOS) activity ). Additionally, there are also other components involved in the stomatal movement such as ABA, cytosolic pH, free calcium, and phospholipids reflecting a complex signaling network (Gayatri et al 2013). This model is further validated by the fact that the ascorbate redox state controls stomatal movement in Arabidopsis guard cells (Chen and Gallie 2004) as DHARsuppressed plants in a decreased ascorbate redox state (but in which total ascorbate levels remain unchanged) exhibit greater stomatal closure.…”

“…Nitric oxide (NO) can be generated either by nitrate reductase (NR) or by a peroxisomal nitric oxide synthase (NOS) activity ). However, there are also other components involved in the stomatal movement such as abscisic acid (ABA), cytosolic pH, free calcium, and phospholipids reflecting a complex signaling network (Gayatri et al 2013). H 2 O 2 can be also generated by the copper amine oxidase (CuAO) or by the respiratory burst oxidase homologue (RBOH) (Shi et al 2012) being both stimulated by ABA emerges in terrestrial plants, suggesting a new functional acquisition during evolutionary adaptation that might contribute to land conquest by plants.…”

Redox-Regulated Mechanisms: Implications for Enhancing Plant Stress Tolerance and Crop Yield

“…This clearly suggested that there exist distinct mechanisms for opening stomata under optimal light condition and for closing under stress condition. Along with H 2 O 2 , nitric oxide (NO) has also emerged as an important regulator of stomata movement (Gayatri et al 2013 ). Recently, it is demonstrated that UV-B-induced stomata closure predominantly involves NO and not H 2 O 2 (Tossi et al 2014 ).…”