Complexity and coordination of root growth at low water potentials: recent advances from transcriptomic and proteomic analyses

Abstract

Progress in understanding root growth regulation and adaptation under water-stressed conditions is reviewed, with emphasis on recent advances from transcriptomic and proteomic analyses of maize and soybean primary roots. In both systems, kinematic characterization of the spatial patterns of cell expansion within the root elongation zone showed that at low water potentials, elongation rates are preferentially maintained towards the root apex but are progressively inhibited at more basal locations resulting in a shortened growth zone. This characterization provided an essential foundation for extensive research into the physiological mechanisms of growth regulation in the maize primary root at low water potentials. Recently, these studies were expanded to include transcriptomic and cell wall proteomic analyses of the maize primary root, and a proteomic analysis of total soluble proteins in the soybean primary root. This review focuses on findings related to protection from oxidative damage, the potential roles of increased apoplastic reactive oxygen species in regulation of wall extension properties and other processes, region-specific phenylpropanoid metabolism as related to accumulation of (iso)flavonoids and wall phenolics and amino acid metabolism. The results provide novel insights into the complexity and coordination of the processes involved in root growth at low water potentials.

Genetic, proteomic and metabolic analysis of the regulation of energy storage in rice seedlings in response to drought

“…In agreement, previous research using maize root has found that water stress enhances proline content through the up-regulation of pyrroline-5-carboxylate synthetase [71]. In addition, increased carbohydrate metabolism may accelerate the synthesis of some amino acids through glycolysis and the tricarboxylic acid cycle [71,72]. Accumulation of amino acids, together with other osmotic regulators, including soluble sugars and ions, decreases the osmotic potential and enhances the capacity for water absorption under drought conditions [70,73].…”

Tillage Effects on Corn Soil-plant-water Continuum in Alfisols of Southern Ohio

“…If macropores exist, preferential root growth occurs resulting in a clustered root system (Logsdon & Allmaras, 1991;Tardieu, 1994). Root growth can be restricted due to increase in penetration resistance, which primarily results from increase in tension in water film between the soil particles on drying (Whalley et al, 2005;Whitmore & Whalley, 2009;Whalley et al, 2005;Mckenzie et al, 2009;White & Kirkgaard, 2010;Yamaguchi & Sharp, 2010). The data presented in the literature on root distribution as affected by NT and CT are not consistent.…”

Stability of Single-Parent Gene Expression Complementation in Maize Hybrids upon Water Deficit Stress

“…Pro contributes to osmotic adjustment by protecting cellular turgor. Consequently, water influx into cells is enabled by a more negative water potential compared with the outside medium (for review, see Yamaguchi and Sharp, 2010). In contrast to these physiological processes, little is known about the metabolic and molecular networks involved in drought adjustment (Spollen et al, 2008;Krasensky and Jonak, 2012).…”

“…The maintenance of root growth is mediated by the plant hormone abscisic acid. Abscisic acid prevents excessive ethylene production and growth inhibition by promoting the transport of Pro to the root apex (for review, see Yamaguchi and Sharp, 2010). Pro contributes to osmotic adjustment by protecting cellular turgor.…”