Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Workshop: Abiotic Stress
Under drought, roots can adapt to continue growth while at the same time sending signals to shoots that inhibit growth above ground. Progress in understanding the network of mechanisms involved in maize primary root growth maintenance under water deficits will be reviewed. These include turgor maintenance by osmotic adjustment, enhanced cell wall loosening, and adjustment of growth anisotropy. The role of the hormone abscisic acid (ABA) in regulating root growth under water deficits will also be addressed. ABA has often been proposed to function in growth inhibition of stressed plants. However, results from mutant and inhibitor studies of endogenous ABA manipulation demonstrate that ABA accumulation is required for root growth maintenance under water deficits. The research has taken advantage of a kinematic approach, i.e. the analysis of spatial and temporal patterns of cell expansion within the growth zone, which has facilitated discovery of the mechanisms involved in the growth responses. The spatial resolution with which this system has been characterized and the physiological knowledge gained to date provides a unique and powerful underpinning for functional genomics studies. We have formed a Plant Root Genomics Consortium (http://rootgenomics.missouri.edu/index.htm) dedicated to root genetics and physiology. Our project goals are to a) characterize changes in transcript profiles and cell wall protein profiles within the growth zone of roots under water deficit in drought-sensitive, drought-tolerant and ABA-deficient maize lines, and b) investigate the production and transport of root signals to provide a better understanding of root to shoot signaling under drought.