Bundle-sheath cell regulation of xylem-mesophyll water transport via aquaporins under drought stress: a target of xylem-borne ABA?
Reads0
Chats0
TLDR
The results support the above hypothesis and highlight the BSCs as hitherto overlooked vasculature sensor compartments, extending throughout the leaf and functioning as 'stress-regulated valves' converting vasculatures chemical signals into leaf hydraulic signals.Abstract:
Summary
The hydraulic conductivity of the leaf vascular system (Kleaf) is dynamic and decreases rapidly under drought stress, possibly in response to the stress phytohormone ABA, which increases sharply in the xylem sap (ABAxyl) during periods of drought. Vascular bundle-sheath cells (BSCs; a layer of parenchymatous cells tightly enwrapping the entire leaf vasculature) have been hypothesized to control Kleaf via the specific activity of BSC aquaporins (AQPs). We examined this hypothesis and provide evidence for drought-induced ABAxyl diminishing BSC osmotic water permeability (Pf) via downregulated activity of their AQPs. ABA fed to the leaf via the xylem (petiole) both decreased Kleaf and led to stomatal closure, replicating the effect of drought. In contrast, smearing ABA on the leaf blade, while also closing stomata, did not decrease Kleaf within 2–3 h of application, demonstrating that Kleaf does not depend entirely on stomatal closure. GFP-labeled BSCs showed decreased Pf in response to ‘drought’ and ABA treatment, and a reversible decrease with HgCl2 (an AQP blocker). These Pf responses, absent in mesophyll cells, suggest stress-regulated AQP activity specific to BSCs, and imply a role for these cells in decreasing Kleaf via a reduction in Pf. Our results support the above hypothesis and highlight the BSCs as hitherto overlooked vasculature sensor compartments, extending throughout the leaf and functioning as ‘stress-regulated valves’ converting vasculature chemical signals (possibly ABAxyl) into leaf hydraulic signals.read more
Citations
More filters
Journal ArticleDOI
Abscisic Acid synthesis and response.
TL;DR: This chapter reviews the current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis.
Journal ArticleDOI
Aquaporins in Plants.
Christophe Maurel,Yann Boursiac,Doan-Trung Luu,Véronique Santoni,Zaigham Shahzad,Lionel Verdoucq +5 more
TL;DR: Research on aquaporins delineates ever expanding fields in plant integrative biology thereby establishing their crucial role in plants.
Journal ArticleDOI
Leaf venation: structure, function, development, evolution, ecology and applications in the past, present and future
Lawren Sack,Christine Scoffoni +1 more
TL;DR: The development and plasticity of leaf venation and its adaptation across environments globally, and a new global data compilation indicating trends relating vein length per unit area to climate, growth form and habitat worldwide are described.
Journal ArticleDOI
Aquaporins: Highly Regulated Channels Controlling Plant Water Relations
TL;DR: This Update integrates data and emphasizes the central role played by aquaporins in regulating plant water relations and demonstrates that variations in root and leaf hydraulic conductivity can be accounted for by Aquaporins but this must be integrated with anatomical considerations.
Journal ArticleDOI
The Grapevine Expression Atlas Reveals a Deep Transcriptome Shift Driving the Entire Plant into a Maturation Program
Marianna Fasoli,Silvia Dal Santo,Sara Zenoni,Giovanni Battista Tornielli,Lorenzo Farina,Anita Zamboni,Andrea Porceddu,Luca Venturini,Manuele Bicego,Vittorio Murino,Alberto Ferrarini,Massimo Delledonne,Mario Pezzotti +12 more
TL;DR: It is found that the whole plant undergoes transcriptomic reprogramming, driving it towards maturity, which may be a defining characteristic of perennial woody plants.
References
More filters
Journal ArticleDOI
Variability among species of stomatal control under fluctuating soil water status and evaporative demand: modelling isohydric and anisohydric behaviours
TL;DR: Stomatal conductance of well-watered plants had no response to VPD when plants were grown in natural soils, suggesting that the opposite result observed in many laboratory experiments might be linked to the low unsaturated hydraulic conductivity of usual potting substrates.
Journal ArticleDOI
Chemical root to shoot signaling under drought
TL;DR: Current knowledge of, and advances in, research on chemical signals that are sent from roots under drought are described and the contribution of these different potential signals is discussed within the context of their role in stress signaling.
Journal ArticleDOI
A Hydraulic Signal in Root-To-Shoot Signalling of Water Shortage
TL;DR: In this article, the authors show that the shoot response to limited soil water supply is not affected by the capacity to generate ABA in the root; however, the response does require ABA biosynthesis and signalling in the shoot.
Journal ArticleDOI
Molecular analysis of SCARECROW function reveals a radial patterning mechanism common to root and shoot
TL;DR: Analysis ofSCR expression and the mutant phenotype from the earliest stages of embryogenesis revealed a tight correlation between defective cell divisions and SCR expression in cells that contribute to ground tissue radial patterning in both embryonic root and shoot.
Journal ArticleDOI
Boron-Toxicity Tolerance in Barley Arising from Efflux Transporter Amplification
Tim Sutton,Ute Baumann,Julie E. Hayes,Nicholas C. Collins,Bu-Jun Shi,Thorsten Schnurbusch,Alison Hay,Gwenda M. Mayo,M. Pallotta,Mark Tester,Peter Langridge +10 more
TL;DR: Bot1 transcript levels identified in barley tissues are consistent with a role in limiting the net entry of boron into the root and in the disposal ofboron from leaves via hydathode guttation.