Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities

While humic substances (HS) are recognized for their role in enhancing plant growth under abiotic stress by modulating hormonal and redox metabolisms, a key question remains: how do HS influence the microbiota associated with plants? This study hypothesizes that the effects of HS extend beyond plant...

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Main Authors: Salomé Lengrand, Benjamin Dubois, Lena Pesenti, Frederic Debode, Anne Legrève
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-11-01
Series:Frontiers in Plant Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fpls.2024.1488671/full
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author Salomé Lengrand
Benjamin Dubois
Lena Pesenti
Frederic Debode
Anne Legrève
author_facet Salomé Lengrand
Benjamin Dubois
Lena Pesenti
Frederic Debode
Anne Legrève
author_sort Salomé Lengrand
collection DOAJ
description While humic substances (HS) are recognized for their role in enhancing plant growth under abiotic stress by modulating hormonal and redox metabolisms, a key question remains: how do HS influence the microbiota associated with plants? This study hypothesizes that the effects of HS extend beyond plant physiology, impacting the plant-associated bacterial community. To explore this, we investigated the combined and individual impacts of HS and osmotic stress on tomato plant physiology and root endophytic communities. Tomatoes were grown within a sterile hydroponic system, which allowed the experiment to focus on seed-transmitted endophytic bacteria. Moreover, sequencing the 16S-ITS-23S region of the rrn operon (~4,500 bp) in a metabarcoding assay using the PNA-chr11 clamp nearly eliminated the reads assigned to Solanum lycopersicum and allowed the species-level identification of these communities. Our findings revealed that HS, osmotic stress, and their combined application induce changes in bacterial endophytic communities. Osmotic stress led to reduced plant growth and a decrease in Bradyrhizobium sp., while the application of HS under osmotic stress resulted in increased tomato growth, accompanied by an increase in Frigoribacterium sp., Roseateles sp., and Hymenobacter sp., along with a decrease in Sphingomonas sp. Finally, HS application under non-stress conditions did not affect plant growth but did alter the endophytic community, increasing Hymenobacter sp. and decreasing Sphingomonas sp. This study enhances the understanding of plant–endophyte interactions under stress and HS application, highlighting the significance of the vertically transmitted core microbiome in tomato roots and suggesting new insights into the mode of action of HS that was used as a biostimulant.
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spelling doaj-art-e10bda44919d4f7eb200a672cfe57f802024-11-19T04:22:40ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2024-11-011510.3389/fpls.2024.14886711488671Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communitiesSalomé Lengrand0Benjamin Dubois1Lena Pesenti2Frederic Debode3Anne Legrève4Université catholique de Louvain (UCLouvain), Earth and Life Institute, Louvain-la-Neuve, BelgiumUnit 1, Bioengineering, Walloon Agricultural Research Centre (CRA–W), Gembloux, BelgiumUniversité catholique de Louvain (UCLouvain), Earth and Life Institute, Louvain-la-Neuve, BelgiumUnit 1, Bioengineering, Walloon Agricultural Research Centre (CRA–W), Gembloux, BelgiumUniversité catholique de Louvain (UCLouvain), Earth and Life Institute, Louvain-la-Neuve, BelgiumWhile humic substances (HS) are recognized for their role in enhancing plant growth under abiotic stress by modulating hormonal and redox metabolisms, a key question remains: how do HS influence the microbiota associated with plants? This study hypothesizes that the effects of HS extend beyond plant physiology, impacting the plant-associated bacterial community. To explore this, we investigated the combined and individual impacts of HS and osmotic stress on tomato plant physiology and root endophytic communities. Tomatoes were grown within a sterile hydroponic system, which allowed the experiment to focus on seed-transmitted endophytic bacteria. Moreover, sequencing the 16S-ITS-23S region of the rrn operon (~4,500 bp) in a metabarcoding assay using the PNA-chr11 clamp nearly eliminated the reads assigned to Solanum lycopersicum and allowed the species-level identification of these communities. Our findings revealed that HS, osmotic stress, and their combined application induce changes in bacterial endophytic communities. Osmotic stress led to reduced plant growth and a decrease in Bradyrhizobium sp., while the application of HS under osmotic stress resulted in increased tomato growth, accompanied by an increase in Frigoribacterium sp., Roseateles sp., and Hymenobacter sp., along with a decrease in Sphingomonas sp. Finally, HS application under non-stress conditions did not affect plant growth but did alter the endophytic community, increasing Hymenobacter sp. and decreasing Sphingomonas sp. This study enhances the understanding of plant–endophyte interactions under stress and HS application, highlighting the significance of the vertically transmitted core microbiome in tomato roots and suggesting new insights into the mode of action of HS that was used as a biostimulant.https://www.frontiersin.org/articles/10.3389/fpls.2024.1488671/fullhumic acidsfulvic acidsdrought stressseed-borne endophytesplant-endophyte interactionsendophytome composition
spellingShingle Salomé Lengrand
Benjamin Dubois
Lena Pesenti
Frederic Debode
Anne Legrève
Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
Frontiers in Plant Science
humic acids
fulvic acids
drought stress
seed-borne endophytes
plant-endophyte interactions
endophytome composition
title Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
title_full Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
title_fullStr Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
title_full_unstemmed Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
title_short Humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
title_sort humic substances increase tomato tolerance to osmotic stress while modulating vertically transmitted endophytic bacterial communities
topic humic acids
fulvic acids
drought stress
seed-borne endophytes
plant-endophyte interactions
endophytome composition
url https://www.frontiersin.org/articles/10.3389/fpls.2024.1488671/full
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AT lenapesenti humicsubstancesincreasetomatotolerancetoosmoticstresswhilemodulatingverticallytransmittedendophyticbacterialcommunities
AT fredericdebode humicsubstancesincreasetomatotolerancetoosmoticstresswhilemodulatingverticallytransmittedendophyticbacterialcommunities
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