Seed Imbibition and Metabolism Contribute Differentially to Initial Assembly of the Soybean Holobiont.

Gerna, Davide; Clara, David; Antonielli, Livio; Mitter, Birgit; Roach, Thomas

Seed Imbibition and Metabolism Contribute Differentially to Initial Assembly of the Soybean Holobiont.

Download

Name

pbiomes-03-23-0019-mf.pdf

Description

visibility:open

Size

5.13 MB

Format

Adobe PDF

Checksum (CRC64NVME)

ZL7YYuFz0Tc=

Resource type

Journal article

Creator (person)

Gerna, Davide

ORCID

Clara, David

Antonielli, Livio

ORCID

Mitter, Birgit

ORCID

Roach, Thomas

ORCID

Date published

January 11, 2024

Abstract

Seed germination critically determines successful plant establishment and agricultural productivity. In the plant holobiont's life cycle, seeds are hubs for microbial communities’ assembly, but what exactly shapes the holobiont during germination remains unknown. Here, 16S rRNA gene amplicon sequencing characterized the bacterial communities in embryonic compartments (cotyledons and axes) and on seed coats pre- and post-germination of four soybean ( Glycine max) cultivars, in the presence or absence of exogenous abscisic acid (ABA), which prevented germination and associated metabolism of seeds that had imbibed. Embryonic compartments were metabolically profiled during germination to design minimal media mimicking the seed endosphere for bacterial growth assays. The distinction between embryonic and seed coat bacterial microbiomes of dry seeds weakened during germination, resulting in the plumule, radicle, cotyledon, and seed coat all hosting the same most abundant and structurally influential genera in germinated seeds of every cultivar. Treatment with ABA prevented the increase of bacterial microbiomes’ richness, but not taxonomic homogenization across seed compartments. Growth assays on minimal media containing the most abundant metabolites that accumulated in germinated seeds revealed that seed reserve mobilization promoted enrichment of copiotrophic bacteria. Our data show that seed imbibition enabled distribution of seed-coat-derived epiphytes into embryos irrespective of germination, while germinative metabolism promoted proliferation of copiotrophic taxa, which predominated in germinated seeds. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .