Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought

ABSTRACT Tree survival under drought conditions depends on the ability to maintain functional xylem and avoid hydraulic failure due to cavitation. Although xylem parenchyma are key sites of metabolic activity in angiosperm wood, the anatomical and gene expression responses of this cell type to droug...

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Main Authors: Rafael Keret, Paul N. Hills, David M. Drew
Format: Article
Language:English
Published: Wiley 2025-06-01
Series:Plant-Environment Interactions
Subjects:
Online Access:https://doi.org/10.1002/pei3.70068
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author Rafael Keret
Paul N. Hills
David M. Drew
author_facet Rafael Keret
Paul N. Hills
David M. Drew
author_sort Rafael Keret
collection DOAJ
description ABSTRACT Tree survival under drought conditions depends on the ability to maintain functional xylem and avoid hydraulic failure due to cavitation. Although xylem parenchyma are key sites of metabolic activity in angiosperm wood, the anatomical and gene expression responses of this cell type to drought stress remain poorly characterized. This study investigated how Eucalyptus grandis W. Hill ex Maiden modifies parenchyma anatomy and gene expression under water deficit to enhance cavitation resistance. Under controlled drought conditions, plants produced significantly smaller ray parenchyma cells with increased frequency. This arrangement reduced the proportion of isolated vessels through elevated ray‐vessel contacts, likely enhancing solute delivery to stressed conduits. Transcriptomic analysis revealed upregulation of aquaporins, lipid transfer proteins, and enzymes involved in triacylglycerol biosynthesis, supporting roles in water transport and nanobubble stabilization under negative pressure. In parallel, genes associated with osmotic regulation, including various sugars, myo‐inositol, and metal ion transporters, were also induced, indicating putative solute‐mediated mechanisms for refilling embolized vessels. This transcriptomic response appears to be primarily triggered by oxidative and hypoxic stress signals. Collectively, these results indicate that xylem parenchyma contribute to embolism resistance by actively redistributing water and supporting hydraulic stability during drought. This work provides mechanistic insights into tree drought adaptation, with implications for forest management and climate resilience strategies.
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spelling doaj-art-ce40c1d40a8040ce97307b53e2c3e93b2025-08-20T03:29:57ZengWileyPlant-Environment Interactions2575-62652025-06-0163n/an/a10.1002/pei3.70068Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During DroughtRafael Keret0Paul N. Hills1David M. Drew2Department of Genetics, Institute for Plant Biotechnology Stellenbosch University Stellenbosch South AfricaDepartment of Genetics, Institute for Plant Biotechnology Stellenbosch University Stellenbosch South AfricaDepartment of Forestry and Wood Sciences Stellenbosch University Stellenbosch central South AfricaABSTRACT Tree survival under drought conditions depends on the ability to maintain functional xylem and avoid hydraulic failure due to cavitation. Although xylem parenchyma are key sites of metabolic activity in angiosperm wood, the anatomical and gene expression responses of this cell type to drought stress remain poorly characterized. This study investigated how Eucalyptus grandis W. Hill ex Maiden modifies parenchyma anatomy and gene expression under water deficit to enhance cavitation resistance. Under controlled drought conditions, plants produced significantly smaller ray parenchyma cells with increased frequency. This arrangement reduced the proportion of isolated vessels through elevated ray‐vessel contacts, likely enhancing solute delivery to stressed conduits. Transcriptomic analysis revealed upregulation of aquaporins, lipid transfer proteins, and enzymes involved in triacylglycerol biosynthesis, supporting roles in water transport and nanobubble stabilization under negative pressure. In parallel, genes associated with osmotic regulation, including various sugars, myo‐inositol, and metal ion transporters, were also induced, indicating putative solute‐mediated mechanisms for refilling embolized vessels. This transcriptomic response appears to be primarily triggered by oxidative and hypoxic stress signals. Collectively, these results indicate that xylem parenchyma contribute to embolism resistance by actively redistributing water and supporting hydraulic stability during drought. This work provides mechanistic insights into tree drought adaptation, with implications for forest management and climate resilience strategies.https://doi.org/10.1002/pei3.70068embolismhydraulic safetytranscriptomevessel associated cellswood anatomy
spellingShingle Rafael Keret
Paul N. Hills
David M. Drew
Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
Plant-Environment Interactions
embolism
hydraulic safety
transcriptome
vessel associated cells
wood anatomy
title Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
title_full Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
title_fullStr Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
title_full_unstemmed Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
title_short Xylem Parenchyma Anatomy and Gene Expression Patterns Indicate Mechanisms of Cavitation Resistance in Eucalyptus grandis During Drought
title_sort xylem parenchyma anatomy and gene expression patterns indicate mechanisms of cavitation resistance in eucalyptus grandis during drought
topic embolism
hydraulic safety
transcriptome
vessel associated cells
wood anatomy
url https://doi.org/10.1002/pei3.70068
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AT paulnhills xylemparenchymaanatomyandgeneexpressionpatternsindicatemechanismsofcavitationresistanceineucalyptusgrandisduringdrought
AT davidmdrew xylemparenchymaanatomyandgeneexpressionpatternsindicatemechanismsofcavitationresistanceineucalyptusgrandisduringdrought