A Spatio-Temporal Understanding of Growth Regulation during the Salt Stress Response in Arabidopsis

Abstract

ORCID IDs: 000-0002-2348-8059 (R.W.); 0000-0002-3998-724X (J.R.D.).Plant environmental responses involve dynamic changes in growth and signaling, yet little is understood as to how progress through these events is regulated. Here, we explored the phenotypic and transcriptional events involved in the acclimation of the Arabidopsis thaliana seedling root to a rapid change in salinity. Using live-imaging analysis, we show that growth is dynamically regulated with a period of quiescence followed by recovery then homeostasis. Through the use of a new highresolution spatio-temporal transcriptional map, we identify the key hormone signaling pathways that regulate specific transcriptional programs, predict their spatial domain of action, and link the activity of these pathways to the regulation of specific phases of growth. We use tissue-specific approaches to suppress the abscisic acid (ABA) signaling pathway and demonstrate that ABA likely acts in select tissue layers to regulate spatially localized transcriptional programs and promote growth recovery. Finally, we show that salt also regulates many tissue-specific and time point-specific transcriptional responses that are expected to modify water transport, Casparian strip formation, and protein translation. Together, our data reveal a sophisticated assortment of regulatory programs acting together to coordinate spatially patterned biological changes involved in the immediate and long-term response to a stressful shift in environment.

Environmental Nitrate Stimulates Abscisic Acid Accumulation in Arabidopsis Root Tips by Releasing It from Inactive Stores

“…Immunofluorescence Reveals a Radial Pattern of ABA Localization in the Growing Root Tip ABA regulates root growth in response to environmental signals such as drought, salt stress, and nitrate, affecting meristem size and cell differentiation and triggering the induction of ABA-responsive gene expression (Signora et al, 2001;Sharp et al, 2004;Zhang et al, 2010;Duan et al, 2013;Geng et al, 2013). However, the spatial localization of ABA within the growing root tip is unknown.…”

Alterations of Endogenous Hormonal Levels in Plants under Drought and Salinity

“…Particularly, ABA is well known for conferring tolerance to abiotic stresses, among the most important are drought and salinity [10]. In response to drought, Arabidopsis plants synthesize ABA in the shoot which has been reported to be transported to the root [11]. It seems to be correlated with a higher ABA precursor (carotenoids) concentration in shoot than roots.…”

VvWRKY13 enhances ABA biosynthesis in Vitis vinifera

“…The root system consists of primary, lateral, and adventitious roots in higher plants, and ABA is reported to be functioning in a complex manner [37][38][39]. In high concentrations, ABA inhibits both primary and lateral root growth [37], nevertheless, it is required in low concentrations for primary root elongation [38,39].…”

“…In high concentrations, ABA inhibits both primary and lateral root growth [37], nevertheless, it is required in low concentrations for primary root elongation [38,39]. The plants defficient in ABA biosynthesis and signaling also has complex ABA related phenotypes.…”