Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 10/15/2012
Publication Date: N/A
Citation: N/A Interpretive Summary: Drought stress is a major environmental factor that limits food production in the world. With the temperature on the earth increasing due to climate change, drought will become a more severe problem for many countries including China, India, and most parts of Africa. Providing enough food to the growing world population will be a major challenge that we will have to face. Traditional breeding had been successful in developing drought tolerant crops in the last several decades; however, it is becoming more difficult to develop drought tolerant crops by this approach due to limited access to the drought tolerant genes in the natural populations of crops and due to its time-consuming process. In contrast, the rapid progress made in plant genomics research and in plant biotechnology research has opened up new possibilities in creating drought tolerant crops through genetic engineering. Among the many successful experiments conducted in laboratories and in the field, two approaches appear to be very promising. One involves increasing activity of a vacuolar membrane-bound proton pump, which leads to increased drought tolerance and salt tolerance in transgenic plants. The other involves increasing cytokinin production only under drought conditions, which dramatically increases drought tolerance in transgenic plants. Both approaches have been tested in greenhouse and field conditions and both appear to work in all plants that have been tested. It is hoped that these approaches will be translated into actual gain in agricultural production soon.
Technical Abstract: Drought and heat are major environmental factors that limit agricultural productivity. Decreased availability of arable land for agricultural production, increased water demand for urban use, and declining aquifer levels are the primary constraints placed on food and fiber production now and in the foreseeable future. These issues are compounded by climate change predictions of increased temperature and rainfall variability in the major agricultural regions of the world, particularly the semi-arid southwestern US. The major task facing the scientific community is providing food and clothing to the increasing global population, and doing so on marginal lands using fewer inputs. To meet these needs, innovative stategies must be developed to increase both drought- and heat-tolerance for crops. Based on previous work in our laboratories and others we provide, here, a brief summary of approaches for engineering stress tolerance in crop plants. These approaches include targeted alterations in ion homeostasis, regulated expression of key stress-responsive genes, and manipulation of leaf senescence. The successful implementation of genetic engineering in abiotic stress improvement will result in the generation of stress tolerant crip varieties for production under reduced input and high temperature regions and significant water savings without associated yield penalties, allowing for sustainable production and economic stability in semi-arid regions.