Related Experiment Video
Updated: Mar 25, 2026

Measuring Gene Expression in Bombarded Barley Aleurone Layers with Increased Throughput
Published on: March 30, 2018
Environmental Nitrate Stimulates Abscisic Acid Accumulation in Arabidopsis Root Tips by Releasing It from Inactive
Christine A Ondzighi-Assoume1, Sanhita Chakraborty2, Jeanne M Harris3
1Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 Department of Plant Sciences, The University of Tennessee, Knoxville, Tennessee 37996.
Abstract:
Abscisic acid (ABA) signaling plays a major role in root system development, regulating growth and root architecture. However, the precise localization of ABA remains undetermined. Here, we present a mechanism in which nitrate signaling stimulates the release of bioactive ABA from the inactive storage form, ABA-glucose ester (ABA-GE). We found that ABA accumulated in the endodermis and quiescent center of Arabidopsis thaliana root tips, mimicking the pattern of SCARECROW expression, and (to lower levels) in the vascular cylinder. Nitrate treatment increased ABA levels in root tips; this stimulation requires the activity of the endoplasmic reticulum-localized, ABA-GE-deconjugating enzyme b-GLUCOSIDASE1, but not de novo ABA biosynthesis. Immunogold labeling demonstrated that ABA is associated with cytoplasmic structures near, but not within, the endoplasmic reticulum. These findings demonstrate a mechanism for nitrate-regulated root growth via regulation of ABA accumulation in the root tip, providing insight into the environmental regulation of root growth.
Related Concept Videos
Adaptations that Reduce Water Loss
Inorganic Nitrogen Assimilation
Key Elements for Plant Nutrition
Transcription
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in the proper synthesis of messenger RNA (mRNA). Regulation of transcription is responsible for the differentiation of all the different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds...
Overview of Nitrogen Metabolism
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
Responses to Drought and Flooding

