Engineering for Drought Tolerance in Horticultural and Ornamental Plants: Lessons from the Studies with Model Plants

Drought is one of the major factors limiting plant growth and productivity. Plant adaptation to drought is dependent on molecular networks for drought perception, signal transduction, expression of a subset of genes and production of metabolites that protect and maintain the structure of cellular components. In general, the drought response pathways can be classified into two categories: one is dependent on the stress hormone abscisic acid (ABA) and the other is ABA-independent. Many genes in these pathways have been identified, thereby providing guidance in choosing genes for engineering of drought tolerance. The review highlights the genes that mediate drought response and tolerance, and discusses lessons learned from engineering for drought tolerance in model plants, such as Arabidopsis, rice and tobacco. Because success of drought tolerance engineering is dependent on not only protein coding regions but also appropriate promoters, this article also reviews the promoters that are crucial for successful engineering of stress tolerance. (C) 2006 by The Haworth Press, Inc. All rights reserved.