Agronomy and Horticulture, Department of
Department of Agronomy and Horticulture: Faculty Publications
Accessibility Remediation
If you are unable to use this item in its current form due to accessibility barriers, you may request remediation through our remediation request form.
Document Type
Article
Date of this Version
6-2004
Citation
PNAS101 (23) June 8, 2004; www.pnas.orgcgidoi10.1073pnas.0401707101
Abstract
Potassium (K+) is an essential nutrient required by plants in large quantities, but changes in soil concentrations may limit K+ acquisition by roots. It is not known how plant root cells sense or signal the changes that occur after the onset of K+ deficiency. Changes in the kinetics of Rb uptake in Arabidopsis roots occur within 6 h after K+ deprivation. Reactive oxygen species (ROS) and ethylene increased when the plants were deprived of K+. ROS accumulated in a discrete region of roots that has been shown to be active in K+ uptake and translocation. Suppression of an NADPH oxidase in Arabidopsis (rhd2), which is involved in ROS production, prevented the up-regulation of genes that are normally induced by K+ deficiency, but the induction of high-affinity K+ transport activity was unchanged. Application of H2O2 restored the expression of genes induced by K+ deficiency in rhd2 and was also sufficient to induce high-affinity K+ transport activity in roots grown under K+-sufficient conditions. ROS production is an early root response to K+ deficiency that modulates gene expression and physiological changes in the kinetics of K+ uptake.