Plant Response to Water‐deficit Stress

Elizabeth A Bray, University of Chicago, Chicago, Illinois, USA

Published online: July 2007

DOI: 10.1002/9780470015902.a0001298.pub2

When plants do not receive sufficient water they are subjected to a stress called water deficit. Water deficit in the plant disrupts many cellular and whole plant functions, having a negative impact on plant growth and reproduction. Plants have evolved many different mechanisms to deal with the occurrence of this stress as it occurs in their environments. Availability of water is the most important factor in the environment that reduces the production of our crops.

Keywords: water-deficit stress; water relations; gene regulation; biotechnology

Figure 1. Resistance to water-deficit stress can arise from mechanisms involving avoidance or tolerance of the water deficit.
Figure 2. Cellular and soil-water potential control water uptake into the cell. Osmotic adjustment, a lowering of cellular osmotic potential, can permit water uptake and restore cellular turgor.
Figure 3. ABA biosynthesis beginning with a carotenoid and proceeding through the major pathway for catabolism. Both synthesis and breakdown contribute to the level of ABA in a particular organ of the plant in response to water deficit. The numbers in boxes represent enzymes that have been cloned in Arabidopsis. (1) 9-cis-epoxycarotenoids dioxygenase 3 (NCED3) catalyses the cleavage of cis-xanthophylls during water-deficit stress. (2) The product xanthoxin is converted into ABA aldehyde by a short-chain alcohol dehydrogenase, ABA2. (3) Abscisic aldehyde oxidase AAO3, an enzyme that requires a sulfurylated form of MoCo (synthesized by (4) MoCo sulfurase (ABA3)), completes the final step of ABA biosynthesis. (5) The key step of ABA catabolism is the hydroxylation of the 8¢ metyl group to yeild 8¢ hydroxy ABA by a cytochrome P450 monooxygenase CYP707A3. Phaseic acid is then formed spontaneously. The increased concentration of ABA initiates a signal transduction pathway through an unknown sensing mechanism. This leads to induction of specific genes.
Figure 4. Classes of genes that are induced by water-deficit stress. The inset shows the different types of transcription factors that induce/repress sets of genes, called regulons.
Figure 5. Approaches to improve crops using our current knowledge of plant gene expression. When individual genes are expressed the size of the regulated gene set depends on the function of the transgene. Manipulating ABA levels or sensitivity may also result in the induction of some genes that are not normally induced under stress conditions.
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    Bray EA (2004) Genes commonly regulated by water-deficit stress in Arabidopsis thaliana. Journal of Experimental Botany 55: 2331–2341.
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 Further Reading
    Maggio A, Zhu J-K, Hasegawa M et al. (2006) Osmogenetics: Aristotle to Arabidopsis. Plant Cell 18: 1542–1557.
    Nambara E and Marion-Poll A (2005) Abscisic acid biosynthesis and catabolism. Annual Review of Plant Biology 56: 165–185. doi: 10.1146/annurev.arplant.56.032604.144046.
    Umezawa T, Fujita M, Fujita Y et al. (2006) Engineering drought tolerance in plants: discovering and tailoring genes to unlock the future. Current Opinion in Biotechnology 17: 113–122.
    Yamaguchi-Shinozaki K and Shinozaki K (2006) Transcriptional regulatory networks in cellular responses and tolerance to dehydration and cold stresses. Annual Review of Plant Biology 57: 781–803.

Related Sub-Topics:

Plant Responses to the Environment | Plant Stress Physiology | Physiological Ecology | Organisms and the Physical Environment
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Article Title: Plant Response to Water‐deficit Stress
 
How to Cite close
Bray, Elizabeth A(Jul 2007) Plant Response to Water‐deficit Stress. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0001298.pub2]