Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation

Abstract Plants function as an integrated system of interconnected organs, with shoots and roots mutually influencing each other. Brassinosteroid (BR) signaling is essential for whole-plant growth, yet the relative importance of shoot versus root BR function in shaping root system architecture (RSA)...

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Main Authors: Hitaishi Khandal, Guy Horev, Bas van den Herik, Yoram Soroka, Tamar Lahav, Tamar Avin-Wittenberg, Kirsten ten Tusscher, Sigal Savaldi-Goldstein
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-59202-6
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author Hitaishi Khandal
Guy Horev
Bas van den Herik
Yoram Soroka
Tamar Lahav
Tamar Avin-Wittenberg
Kirsten ten Tusscher
Sigal Savaldi-Goldstein
author_facet Hitaishi Khandal
Guy Horev
Bas van den Herik
Yoram Soroka
Tamar Lahav
Tamar Avin-Wittenberg
Kirsten ten Tusscher
Sigal Savaldi-Goldstein
author_sort Hitaishi Khandal
collection DOAJ
description Abstract Plants function as an integrated system of interconnected organs, with shoots and roots mutually influencing each other. Brassinosteroid (BR) signaling is essential for whole-plant growth, yet the relative importance of shoot versus root BR function in shaping root system architecture (RSA) remains unclear. Here, we directly tackle this question using micro-grafts between wild-type and BR-null mutants in both Arabidopsis and tomato, assisted by phenotyping, transcriptomics, metabolic profiling, transmission electron microscopy, and modeling approaches. These analyses demonstrate that shoot BR, by determining root carbon availability, allows for a full rescue of mutant root biomass, while loss of shoot BR attenuates root growth. In parallel, root BR dictates the spatial distribution of carbon along the root, through local regulation of growth anisotropy and cell wall thickness, shaping root morphology. A newly developed “grow and branch” simulation model demonstrates that these shoot- and root-derived BR effects are sufficient to explain and predict root growth dynamics and branching phenotype in wild-type, BR-deficient mutants, and micro-graft combinations. Our interdisciplinary approach, applied to two plant species and integrating shoot and root hormonal functions, provides a new understanding of how RSA is modulated at various scales.
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spelling doaj-art-ceb7d870d4e548f4b6ceed3ddd18b4ff2025-08-20T02:11:11ZengNature PortfolioNature Communications2041-17232025-04-0116111610.1038/s41467-025-59202-6Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocationHitaishi Khandal0Guy Horev1Bas van den Herik2Yoram Soroka3Tamar Lahav4Tamar Avin-Wittenberg5Kirsten ten Tusscher6Sigal Savaldi-Goldstein7Faculty of Biology, Technion—Israel Institute of TechnologyMIGAL—Galilee Research InstituteComputational Developmental Biology Group, Department of Biology, Faculty of Science, Utrecht UniversityAlexander Silberman Institute of Life Sciences, The Hebrew University of JerusalemFaculty of Biology, Technion—Israel Institute of TechnologyAlexander Silberman Institute of Life Sciences, The Hebrew University of JerusalemComputational Developmental Biology Group, Department of Biology, Faculty of Science, Utrecht UniversityFaculty of Biology, Technion—Israel Institute of TechnologyAbstract Plants function as an integrated system of interconnected organs, with shoots and roots mutually influencing each other. Brassinosteroid (BR) signaling is essential for whole-plant growth, yet the relative importance of shoot versus root BR function in shaping root system architecture (RSA) remains unclear. Here, we directly tackle this question using micro-grafts between wild-type and BR-null mutants in both Arabidopsis and tomato, assisted by phenotyping, transcriptomics, metabolic profiling, transmission electron microscopy, and modeling approaches. These analyses demonstrate that shoot BR, by determining root carbon availability, allows for a full rescue of mutant root biomass, while loss of shoot BR attenuates root growth. In parallel, root BR dictates the spatial distribution of carbon along the root, through local regulation of growth anisotropy and cell wall thickness, shaping root morphology. A newly developed “grow and branch” simulation model demonstrates that these shoot- and root-derived BR effects are sufficient to explain and predict root growth dynamics and branching phenotype in wild-type, BR-deficient mutants, and micro-graft combinations. Our interdisciplinary approach, applied to two plant species and integrating shoot and root hormonal functions, provides a new understanding of how RSA is modulated at various scales.https://doi.org/10.1038/s41467-025-59202-6
spellingShingle Hitaishi Khandal
Guy Horev
Bas van den Herik
Yoram Soroka
Tamar Lahav
Tamar Avin-Wittenberg
Kirsten ten Tusscher
Sigal Savaldi-Goldstein
Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
Nature Communications
title Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
title_full Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
title_fullStr Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
title_full_unstemmed Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
title_short Root growth and branching are enabled by brassinosteroid-regulated growth anisotropy and carbon allocation
title_sort root growth and branching are enabled by brassinosteroid regulated growth anisotropy and carbon allocation
url https://doi.org/10.1038/s41467-025-59202-6
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