Root Suberin Plays Important Roles in Reducing Water Loss and Sodium Uptake in Arabidopsis thaliana.

Nayana D G De Silva,Isabel Molina,Peter Ryser,Keith Hubbard,Owen Rowland,Jhadeswar Murmu,Denise Chabot

doi:10.3390/metabo11110735

Nayana D G De Silva, Isabel Molina + Show 5 more

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https://doi.org/10.3390/metabo11110735

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Abstract

Suberin is a cell-wall-associated hetero-polymer deposited in specific plant tissues. The precise role of its composition and lamellae structure in protecting plants against abiotic stresses is unclear. In Arabidopsis thaliana, we tested the biochemical and physiological responses to water deficiency and NaCl treatment in mutants that are differentially affected in suberin composition and lamellae structure. Chronic drought stress increased suberin and suberin-associated waxes in wild-type plants. Suberin-deficient mutants were not more susceptible than the wild-type to the chronic drought stress imposed in this study. Nonetheless, the cyp86a1-1 cyp86b1-1 mutant, which had a severely altered suberin composition and lamellae structure, exhibited increased water loss through the root periderm. Cyp86a1-1 cyp86b1-1 also recorded lower relative water content in leaves. The abcg2-1 abcg6-1 abcg20-1 mutant, which has altered suberin composition and lamellae, was very sensitive to NaCl treatment. Furthermore, cyp86a1-1 cyp86b1-1 recorded a significant drop in the leaf K/Na ratio, indicating salt sensitivity. The far1-2 far4-1 far5-1 mutant, which did not show structural defects in the suberin lamellae, had similar responses to drought and NaCl treatments as the wild-type. Our results provide evidence that the suberin amount and lamellae structure are key features in the barrier function of suberin in reducing water loss and reducing sodium uptake through roots for better performance under drought and salt stresses.

Highlights

Resistance to drought and high salinity have been the main foci in crop improvement efforts due to reductions in crop productivity caused by climate change [1]
By investigating the chemical and phenotypic responses to chronic drought and NaCl stresses in our Arabidopsis mutant collection, we report that suberin composition and lamellae structure are important to reduce water loss through the root periderm and to restrict uncontrolled Na movement to the shoot through the roots
We report changes in Arabidopsis root suberin accumulation in response to chronic water deficiency and high NaCl in wild-type plants

Summary

Introduction

Resistance to drought and high salinity have been the main foci in crop improvement efforts due to reductions in crop productivity caused by climate change [1]. A better understanding of chronic drought stress and high NaCl soil concentrations in relation to plant health is of great importance for sustainable agriculture. Plants have evolved multiple acclimation and adaptation mechanisms to respond to environmental stresses. Analysis of these protective mechanisms will contribute to our knowledge of plant tolerance to stress conditions. Plants have various hydrophobic barriers that provide protection against water loss. Suberin is one such cell-wall-associated barrier located in certain tissues, such as the root endodermis and periderm [4]. In Arabidopsis root waxes, the major components are alkyl hydroxycinnamates (AHCs) [10], alkyl coumarates and alkyl caffeates [8,9]

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