Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture

Soybean bradyrhizobia (<i>Bradyrhizobium</i> spp.) are symbiotic root-nodulating bacteria that fix atmospheric nitrogen for the host plant. The University of Delaware <i>Bradyrhizobium</i> Culture Collection (UDBCC; 353 accessions) was created to study the diversity and ecolo...

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Main Authors: Vanessa A. Richards, Barbra D. Ferrell, Shawn W. Polson, K. Eric Wommack, Jeffry J. Fuhrmann
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Viruses
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Online Access:https://www.mdpi.com/1999-4915/16/11/1750
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author Vanessa A. Richards
Barbra D. Ferrell
Shawn W. Polson
K. Eric Wommack
Jeffry J. Fuhrmann
author_facet Vanessa A. Richards
Barbra D. Ferrell
Shawn W. Polson
K. Eric Wommack
Jeffry J. Fuhrmann
author_sort Vanessa A. Richards
collection DOAJ
description Soybean bradyrhizobia (<i>Bradyrhizobium</i> spp.) are symbiotic root-nodulating bacteria that fix atmospheric nitrogen for the host plant. The University of Delaware <i>Bradyrhizobium</i> Culture Collection (UDBCC; 353 accessions) was created to study the diversity and ecology of soybean bradyrhizobia. Some UDBCC accessions produce temperate (lysogenic) bacteriophages spontaneously under routine culture conditions without chemical or other apparent inducing agents. Spontaneous phage production may promote horizontal gene transfer and shape bacterial genomes and associated phenotypes. A diverse subset (n = 98) of the UDBCC was examined for spontaneously produced virus-like particles (VLPs) using epifluorescent microscopy, with a majority (69%) producing detectable VLPs (>1 × 10<sup>7</sup> mL<sup>−1</sup>) in laboratory culture. Phages from the higher-producing accessions (>2.0 × 10<sup>8</sup> VLP mL<sup>−1</sup>; n = 44) were examined using transmission electron microscopy. Diverse morphologies were observed, including various tail types and lengths, capsid sizes and shapes, and the presence of collars or baseplates. In many instances, putative extracellular vesicles of a size similar to virions were also observed. Three of the four species examined (<i>B. japonicum</i>, <i>B. elkanii</i>, and <i>B. diazoefficiens</i>) produced apparently tailless phages. All species except <i>B. ottawaense</i> also produced siphovirus-like phages, while all but <i>B. diazoefficiens</i> additionally produced podovirus-like phages. Myovirus-like phages were restricted to <i>B. japonicum</i> and <i>B. elkanii.</i> At least three strains were polylysogens, producing up to three distinct morphotypes. These observations suggest spontaneously produced phages may play a significant role in the ecology and evolution of soybean bradyrhizobia.
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spelling doaj-art-4cf2ec1ea54f4cf8812a03c5e8dc58f62025-08-20T01:54:08ZengMDPI AGViruses1999-49152024-11-011611175010.3390/v16111750Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in CultureVanessa A. Richards0Barbra D. Ferrell1Shawn W. Polson2K. Eric Wommack3Jeffry J. Fuhrmann4Department of Biological Sciences, University of Delaware, Newark, DE 19716, USADepartment of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USADepartment of Computer and Information Sciences, University of Delaware, Newark, DE 19713, USADepartment of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USADepartment of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USASoybean bradyrhizobia (<i>Bradyrhizobium</i> spp.) are symbiotic root-nodulating bacteria that fix atmospheric nitrogen for the host plant. The University of Delaware <i>Bradyrhizobium</i> Culture Collection (UDBCC; 353 accessions) was created to study the diversity and ecology of soybean bradyrhizobia. Some UDBCC accessions produce temperate (lysogenic) bacteriophages spontaneously under routine culture conditions without chemical or other apparent inducing agents. Spontaneous phage production may promote horizontal gene transfer and shape bacterial genomes and associated phenotypes. A diverse subset (n = 98) of the UDBCC was examined for spontaneously produced virus-like particles (VLPs) using epifluorescent microscopy, with a majority (69%) producing detectable VLPs (>1 × 10<sup>7</sup> mL<sup>−1</sup>) in laboratory culture. Phages from the higher-producing accessions (>2.0 × 10<sup>8</sup> VLP mL<sup>−1</sup>; n = 44) were examined using transmission electron microscopy. Diverse morphologies were observed, including various tail types and lengths, capsid sizes and shapes, and the presence of collars or baseplates. In many instances, putative extracellular vesicles of a size similar to virions were also observed. Three of the four species examined (<i>B. japonicum</i>, <i>B. elkanii</i>, and <i>B. diazoefficiens</i>) produced apparently tailless phages. All species except <i>B. ottawaense</i> also produced siphovirus-like phages, while all but <i>B. diazoefficiens</i> additionally produced podovirus-like phages. Myovirus-like phages were restricted to <i>B. japonicum</i> and <i>B. elkanii.</i> At least three strains were polylysogens, producing up to three distinct morphotypes. These observations suggest spontaneously produced phages may play a significant role in the ecology and evolution of soybean bradyrhizobia.https://www.mdpi.com/1999-4915/16/11/1750<i>Bradyrhizobium</i>soybeanbacteriophagesphage inductionlysogeny
spellingShingle Vanessa A. Richards
Barbra D. Ferrell
Shawn W. Polson
K. Eric Wommack
Jeffry J. Fuhrmann
Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
Viruses
<i>Bradyrhizobium</i>
soybean
bacteriophages
phage induction
lysogeny
title Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
title_full Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
title_fullStr Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
title_full_unstemmed Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
title_short Soybean <i>Bradyrhizobium</i> spp. Spontaneously Produce Abundant and Diverse Temperate Phages in Culture
title_sort soybean i bradyrhizobium i spp spontaneously produce abundant and diverse temperate phages in culture
topic <i>Bradyrhizobium</i>
soybean
bacteriophages
phage induction
lysogeny
url https://www.mdpi.com/1999-4915/16/11/1750
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