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The hierarchy of root branching order determines bacterial composition, microbial carrying capacity and microbial filtering

The hierarchy of root branching order determines bacterial composition, microbial carrying capacity and microbial filtering
The hierarchy of root branching order determines bacterial composition, microbial carrying capacity and microbial filtering

Fine roots vary dramatically in their functions, which range from resource absorption to within-plant resource transport. These differences should alter resource availability to root-associated microorganisms, yet most root microbiome studies involve fine root homogenization. We hypothesized that microbial filtering would be greatest in the most distal roots. To test this, we sampled roots of six temperate tree species from a 23-year-old common garden planting, separating by branching order. Rhizoplane bacterial composition was characterized with 16S rRNA gene sequencing, while bacterial abundance was determined on a subset of trees through flow cytometry. Root order strongly impacted composition across tree species, with absorptive lower order roots exerting the greatest selective pressure. Microbial carrying capacity was higher in absorptive roots in two of three tested tree species. This study indicates lower order roots as the main point of microbial interaction with fine roots, suggesting that root homogenization could mask microbial recruitment signatures.

2399-3642
King, William L.
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Yates, Caylon F.
3fcb4ec9-4250-4ddf-b3f2-e29002d90ef0
Guo, Jing
e51fdc35-39a7-4188-9268-5a5d03ad908a
Fleishman, Suzanne M.
88ee624b-af52-4918-be7c-c8d4ad15b0c7
Trexler, Ryan V.
d2d83916-b67a-40a5-b175-c0431cd80f98
Centinari, Michela
59a42090-5ebc-4f41-abca-e68dbfe19c41
Bell, Terrence H.
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Eissenstat, David M.
09aec4a5-7252-49da-9aab-6fcecb19fd0f
King, William L.
0bd4328a-34ba-4b9a-bf4e-1442c18c43fc
Yates, Caylon F.
3fcb4ec9-4250-4ddf-b3f2-e29002d90ef0
Guo, Jing
e51fdc35-39a7-4188-9268-5a5d03ad908a
Fleishman, Suzanne M.
88ee624b-af52-4918-be7c-c8d4ad15b0c7
Trexler, Ryan V.
d2d83916-b67a-40a5-b175-c0431cd80f98
Centinari, Michela
59a42090-5ebc-4f41-abca-e68dbfe19c41
Bell, Terrence H.
29863b8c-a89c-4077-b22d-62052cfb7225
Eissenstat, David M.
09aec4a5-7252-49da-9aab-6fcecb19fd0f

King, William L., Yates, Caylon F., Guo, Jing, Fleishman, Suzanne M., Trexler, Ryan V., Centinari, Michela, Bell, Terrence H. and Eissenstat, David M. (2021) The hierarchy of root branching order determines bacterial composition, microbial carrying capacity and microbial filtering. Communications Biology, 4 (1), [483]. (doi:10.1038/s42003-021-01988-4).

Record type: Article

Abstract

Fine roots vary dramatically in their functions, which range from resource absorption to within-plant resource transport. These differences should alter resource availability to root-associated microorganisms, yet most root microbiome studies involve fine root homogenization. We hypothesized that microbial filtering would be greatest in the most distal roots. To test this, we sampled roots of six temperate tree species from a 23-year-old common garden planting, separating by branching order. Rhizoplane bacterial composition was characterized with 16S rRNA gene sequencing, while bacterial abundance was determined on a subset of trees through flow cytometry. Root order strongly impacted composition across tree species, with absorptive lower order roots exerting the greatest selective pressure. Microbial carrying capacity was higher in absorptive roots in two of three tested tree species. This study indicates lower order roots as the main point of microbial interaction with fine roots, suggesting that root homogenization could mask microbial recruitment signatures.

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More information

Published date: 19 April 2021
Additional Information: Funding Information: This research was supported by the USDA National Institute of Food and Agriculture (NIFA) Foundational Program (Accession #1014758) and by the USDA NIFA Federal Appropriation under Project #PEN0 4628 (Accession #1014131), Project #PEN0 4744 (Accession #1023222), and Project #PEN0 4651 (Accession #1016233). Partial support was also provided by the China Scholarship Council. We thank Timothy Peoples, Franco Acevedo Luco, Jeremy Harper, Amanda Seow, and Wenqi Luo for their help with root sampling, and Kevin Hockett for the use of the sonic water bath and technical advice. Publisher Copyright: © 2021, The Author(s).

Identifiers

Local EPrints ID: 486649
URI: http://eprints.soton.ac.uk/id/eprint/486649
ISSN: 2399-3642
PURE UUID: 152dda63-a554-4f1b-ba6b-86ba996cd5d4
ORCID for William L. King: ORCID iD orcid.org/0000-0001-7272-8242

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Date deposited: 30 Jan 2024 17:55
Last modified: 06 Jun 2024 02:20

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Contributors

Author: William L. King ORCID iD
Author: Caylon F. Yates
Author: Jing Guo
Author: Suzanne M. Fleishman
Author: Ryan V. Trexler
Author: Michela Centinari
Author: Terrence H. Bell
Author: David M. Eissenstat

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