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A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress

Root exudates are thought to play an important role in plant-microbial interactions. In return for nutrition, soil bacteria can increase the bioavailability of soil nutrients. However, root exudates typically decrease in situations such as drought, calling into question the efficacy of solvation and...

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Autores principales: Oppenheimer-Shaanan, Yaara, Jakoby, Gilad, Starr, Maya L, Karliner, Romiel, Eilon, Gal, Itkin, Maxim, Malitsky, Sergey, Klein, Tamir
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9385208/
https://www.ncbi.nlm.nih.gov/pubmed/35858113
http://dx.doi.org/10.7554/eLife.79679
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author Oppenheimer-Shaanan, Yaara
Jakoby, Gilad
Starr, Maya L
Karliner, Romiel
Eilon, Gal
Itkin, Maxim
Malitsky, Sergey
Klein, Tamir
author_facet Oppenheimer-Shaanan, Yaara
Jakoby, Gilad
Starr, Maya L
Karliner, Romiel
Eilon, Gal
Itkin, Maxim
Malitsky, Sergey
Klein, Tamir
author_sort Oppenheimer-Shaanan, Yaara
collection PubMed
description Root exudates are thought to play an important role in plant-microbial interactions. In return for nutrition, soil bacteria can increase the bioavailability of soil nutrients. However, root exudates typically decrease in situations such as drought, calling into question the efficacy of solvation and bacteria-dependent mineral uptake in such stress. Here, we tested the hypothesis of exudate-driven microbial priming on Cupressus saplings grown in forest soil in custom-made rhizotron boxes. A 1-month imposed drought and concomitant inoculations with a mix of Bacillus subtilis and Pseudomonas stutzeri, bacteria species isolated from the forest soil, were applied using factorial design. Direct bacteria counts and visualization by confocal microscopy showed that both bacteria associated with Cupressus roots. Interestingly, root exudation rates increased 2.3-fold with bacteria under drought, as well as irrigation. Forty-four metabolites in exudates were significantly different in concentration between irrigated and drought trees, including phenolic acid compounds and quinate. When adding these metabolites as carbon and nitrogen sources to bacterial cultures of both bacterial species, eight of nine metabolites stimulated bacterial growth. Importantly, soil phosphorous bioavailability was maintained only in inoculated trees, mitigating drought-induced decrease in leaf phosphorus and iron. Our observations of increased root exudation rate when drought and inoculation regimes were combined support the idea of root recruitment of beneficial bacteria, especially under water stress.
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spelling pubmed-93852082022-08-18 A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress Oppenheimer-Shaanan, Yaara Jakoby, Gilad Starr, Maya L Karliner, Romiel Eilon, Gal Itkin, Maxim Malitsky, Sergey Klein, Tamir eLife Ecology Root exudates are thought to play an important role in plant-microbial interactions. In return for nutrition, soil bacteria can increase the bioavailability of soil nutrients. However, root exudates typically decrease in situations such as drought, calling into question the efficacy of solvation and bacteria-dependent mineral uptake in such stress. Here, we tested the hypothesis of exudate-driven microbial priming on Cupressus saplings grown in forest soil in custom-made rhizotron boxes. A 1-month imposed drought and concomitant inoculations with a mix of Bacillus subtilis and Pseudomonas stutzeri, bacteria species isolated from the forest soil, were applied using factorial design. Direct bacteria counts and visualization by confocal microscopy showed that both bacteria associated with Cupressus roots. Interestingly, root exudation rates increased 2.3-fold with bacteria under drought, as well as irrigation. Forty-four metabolites in exudates were significantly different in concentration between irrigated and drought trees, including phenolic acid compounds and quinate. When adding these metabolites as carbon and nitrogen sources to bacterial cultures of both bacterial species, eight of nine metabolites stimulated bacterial growth. Importantly, soil phosphorous bioavailability was maintained only in inoculated trees, mitigating drought-induced decrease in leaf phosphorus and iron. Our observations of increased root exudation rate when drought and inoculation regimes were combined support the idea of root recruitment of beneficial bacteria, especially under water stress. eLife Sciences Publications, Ltd 2022-07-20 /pmc/articles/PMC9385208/ /pubmed/35858113 http://dx.doi.org/10.7554/eLife.79679 Text en © 2022, Oppenheimer-Shaanan et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Ecology
Oppenheimer-Shaanan, Yaara
Jakoby, Gilad
Starr, Maya L
Karliner, Romiel
Eilon, Gal
Itkin, Maxim
Malitsky, Sergey
Klein, Tamir
A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title_full A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title_fullStr A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title_full_unstemmed A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title_short A dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
title_sort dynamic rhizosphere interplay between tree roots and soil bacteria under drought stress
topic Ecology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9385208/
https://www.ncbi.nlm.nih.gov/pubmed/35858113
http://dx.doi.org/10.7554/eLife.79679
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