Conventional breeding has been underway for a number of years to develop crop plants more tolerant of drought conditions. Not surprisingly, this highly desirable outcome is also being approached from the angle of genetic engineering. Abscisic acid is a plant growth regulation molecule produced by plants that affects both short and long term changes. A short-term response naturally occurring in a plant involves abscisic acid production during periods of drought to act on guard cells of stomata causing them to close for water retention. During this time, photosynthesis is slowed due to reduced intake of carbon dioxide, but survival is a priority. Chemicals to artificially induce abscisic acid production are of interest, however none exist for this purpose. In the development of drought resistant plants, the strategy of this research was to alter the genes in one of the abscisic acid receptor pathways of the plant to respond to application of a registered fungicide. To see if the process was working, Arabidopsis transgenic plants were treated with the fungicide. When photographed with an infrared camera, tissues were indicated as being warmer than their control counterparts, an expected outcome without the cooling benefit of transpiration. Test plants were grown without water for 11 days, after which time the control plants perished. When watering resumed, the test plants recovered.
Nature 520, 545–548