Advances in Molecular Breeding Toward Drought and Salt Tolerant Crops
Plant stress caused by drought and salinity are among the major constraints on crop production and food security worldwide. Breeding programs to improve crop yield in dry and saline environments have progressed slowly due to our limited understandin
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ELIZABETH A. BRAY Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA Abstract:
Soil-water-deficit stress causes many changes in the biology of the plant cell beginning with the perception of the stress followed by changes that promote the acclimation to the stress. The mechanism by which plant cells transduce the physical stress of loss of water to biochemical changes in the cell continues to elude plant biologists. Using modern techniques that allow measurements of thousands of changes in gene expression at one time, researchers have catalogued and are beginning to make progress in interpreting the function of the many changes in gene expression. Although, it still remains a challenge to understand the function and relevance of many of these responses. There are indications that laboratory stress conditions intended to mimic plant water-deficit stress do not cause a universal water stress response; only a small number of genes are commonly induced when plants are subjected to water-deficit stress in different laboratories. Researchers remain optimistic that lessons learned from the molecular response of Arabidopsis plants to stress can be used to improve crops for growth under non ideal field conditions and lessen the need for irrigation in areas of the world where water availabilty for agriculture is decreasing
Keywords:
gene expression, microarray, soil water deficit, stress perception
1.
INTRODUCTION
Plant water deficits caused by inadequate soil water content, especially during the growing season, may occur throughout the world triggering significant losses in crop productivity. Large areas of the world are prone to poor soil moisture conditions for plant growth and development (Figure 1). Significant problems are predicted for food production in the future due to the limited availability of fresh water suitable for agriculture (Jury and Vaux, 2005). The aridic or xeric soil moisture regimes, which generally can not support crop production without irrigation, are common throughout the world. Further obstacles for crop production must be considered in different regions of the world where varied combinations of stresses, depending upon such characteristics as soil type and temperature, can alter plant responses to the environment locally. 121 M.A. Jenks et al. (eds.), Advances in Molecular Breeding Toward Drought and Salt Tolerant Crops, 121–140. © 2007 Springer.
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BRAY
Figure 1. A map of the soil moisture regimes of the world. The aridic and xeric soil moisture regimes are the most limiting to plant growth and development. The aridic soil moisture regime does not have a period of water availability as long as 90 consecutive days when the soil temperature is above 8°C. The xeric soil moisture regime has a limited amount of water but it does not occur at optimum periods for plant growth. The ustic soil moisture regime has a limited amount of water available at a time when soil temperature is optimum for plant growth. (From the United States Department of A
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