Signalling drought in guard cells

Abstract

A number of environmental conditions including drought, low humidity, cold and salinity subject plants to osmotic stress. A rapid plant response to such stress conditions is stomatal closure to reduce water loss from plants. From an external stress signal to stomatal closure, many molecular components constitute a signal transduction network that couples the stimulus to the response. Numerous studies have been directed to resolving the framework and molecular details of stress signalling pathways in plants. In guard cells, studies focus on the regulation of ion channels by abscisic acid (ABA), a chemical messenger for osmotic stress. Calcium, protein kinases and phosphatases, and membrane trafficking components have been shown to play a role in ABA signalling process in guard cells. Studies also implicate ABA-independent regulation of ion channels by osmotic stress. In particular, a direct osmosensing pathway for ion channel regulation in guard cells has been identified. These pathways form a complex signalling web that monitors water status in the environment and initiates responses in stomatal movements.

Effects of Coronatine on Growth, Gas Exchange Traits, Chlorophyll Content, Antioxidant Enzymes and Lipid Peroxidation in Maize (Zea mays L.) Seedlings under Simulated Drought Stress

“…This effect was manifested by an increase in RWC and seedling growth. Our results are in conformity with those of Jiang and Zhang (2001;2002) who examined the effect of low concentration (0.5 mM) of ABA on maize seedlings.…”

“…Todorov et al (1998) also found a higher rate of transpiration in maize plants treated with ABA under drought condition. Coronatine might have regulated the stomatal conductivity to reduce leaf water consumption under drought stress as reported for ABA (Schroeder et al, 2001;Luan, 2002) and JA or methyl jasmonate (MeJA) (Lan et al, 2004), but this remains to be examined further.…”

ABA Increased Soybean Yield by Enhancing Production of Carbohydrates and Their Allocation in Seed

“…It has been demonstrated that ABA is able to alleviate the water stress not only in daily variations but also in long term draught by provoking a stomatal closure, since stomata are responsible for the major proportion of plant water losses (Leung & Giraudat, 1998;Zhang & Outlaw, 2001;Taiz & Zeiger, 2006). In fact, the signal transduction in guard cells in response to ABA has been well documented (Luan 2002;Levchenko et al, 2005;Pei & Kuchitsu 2005;Vahisalu et al, 2008). During seed development, ABA has a main role in regulating synthesis of proteins and lipids and in promoting the seed's tolerance to dryness.…”

Drought-induced changes in the actin cytoskeleton of barley (Hordeum vulgare L.) leaves

“…HVA1 expression was reported to be highly (but not entirely) ABA-independent under drought stress conditions (Wójcik-Jagła et al 2012). The fact that HVA1 showed altered response to drought suggests an intriguing possibility that actin acts independently of ABA as well (Luan 2002). AFs acting as an 'osmosensor' in ABA-independent drought response were suggested by Liu and Luan (1998) for the guard cells.…”