Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients

Soybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus <i>Bradyrhizobium</i>. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation....

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Main Authors: Armaan Kaur Sandhu, Senthil Subramanian, Volker S. Brözel
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Nitrogen
Subjects:
Online Access:https://www.mdpi.com/2504-3129/2/4/31
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author Armaan Kaur Sandhu
Senthil Subramanian
Volker S. Brözel
author_facet Armaan Kaur Sandhu
Senthil Subramanian
Volker S. Brözel
author_sort Armaan Kaur Sandhu
collection DOAJ
description Soybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus <i>Bradyrhizobium</i>. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation. Bacterial surface properties and motility are known to vary with chemical composition of the culture medium, and root adhesion and nodulation occur in a soil environment rather than laboratory medium. We asked whether the nodulation-promoting factors motility, surface hydrophobicity and surface adhesion of <i>Bradyrhizobium</i> are affected by growth in a soil nutrient environment. <i>B. diazoefficiens</i> USDA 110, 126, 3384, and <i>B. elkanii</i> USDA 26 were grown in mineral salt medium with peptone, yeast extract and arabinose (PSY), and in a soil extracted soluble organic matter (SESOM) medium. Surface hydrophobicity was determined by partitioning into hydrocarbon, motility by transition through soft agar, and surface-exposed saccharides by lectin profiling, followed by biofilm formation and soybean root adhesion capacity of populations. SESOM-grown populations were generally less motile and more hydrophobic. They bound fewer lectins than PSY-grown populations, indicating a simpler surface saccharide profile. SESOM populations of USDA 110 did not form detectable biofilm, but showed increased binding to soy roots. Our results indicate that growth in a soil environment impacts surface properties, motility, and subsequent soy root adhesion propensity. Hence, evaluation of <i>Bradyrhizobium</i> for nodulation efficiency should be performed using soil from the specific field where the soybeans are to be planted, rather than laboratory culture media.
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spelling doaj.art-b6e576187ae641d6a76649b477baf6462023-11-23T09:53:51ZengMDPI AGNitrogen2504-31292021-11-012446147310.3390/nitrogen2040031Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted NutrientsArmaan Kaur Sandhu0Senthil Subramanian1Volker S. Brözel2Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USADepartment of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USADepartment of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USASoybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus <i>Bradyrhizobium</i>. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation. Bacterial surface properties and motility are known to vary with chemical composition of the culture medium, and root adhesion and nodulation occur in a soil environment rather than laboratory medium. We asked whether the nodulation-promoting factors motility, surface hydrophobicity and surface adhesion of <i>Bradyrhizobium</i> are affected by growth in a soil nutrient environment. <i>B. diazoefficiens</i> USDA 110, 126, 3384, and <i>B. elkanii</i> USDA 26 were grown in mineral salt medium with peptone, yeast extract and arabinose (PSY), and in a soil extracted soluble organic matter (SESOM) medium. Surface hydrophobicity was determined by partitioning into hydrocarbon, motility by transition through soft agar, and surface-exposed saccharides by lectin profiling, followed by biofilm formation and soybean root adhesion capacity of populations. SESOM-grown populations were generally less motile and more hydrophobic. They bound fewer lectins than PSY-grown populations, indicating a simpler surface saccharide profile. SESOM populations of USDA 110 did not form detectable biofilm, but showed increased binding to soy roots. Our results indicate that growth in a soil environment impacts surface properties, motility, and subsequent soy root adhesion propensity. Hence, evaluation of <i>Bradyrhizobium</i> for nodulation efficiency should be performed using soil from the specific field where the soybeans are to be planted, rather than laboratory culture media.https://www.mdpi.com/2504-3129/2/4/31<i>Bradyrhizobium</i>attachmentrootbiofilmlectinsoybean
spellingShingle Armaan Kaur Sandhu
Senthil Subramanian
Volker S. Brözel
Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
Nitrogen
<i>Bradyrhizobium</i>
attachment
root
biofilm
lectin
soybean
title Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
title_full Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
title_fullStr Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
title_full_unstemmed Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
title_short Surface Properties and Adherence of <i>Bradyrhizobium diazoefficiens</i> to <i>Glycine max</i> Roots Are Altered When Grown in Soil Extracted Nutrients
title_sort surface properties and adherence of i bradyrhizobium diazoefficiens i to i glycine max i roots are altered when grown in soil extracted nutrients
topic <i>Bradyrhizobium</i>
attachment
root
biofilm
lectin
soybean
url https://www.mdpi.com/2504-3129/2/4/31
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AT senthilsubramanian surfacepropertiesandadherenceofibradyrhizobiumdiazoefficiensitoiglycinemaxirootsarealteredwhengrowninsoilextractednutrients
AT volkersbrozel surfacepropertiesandadherenceofibradyrhizobiumdiazoefficiensitoiglycinemaxirootsarealteredwhengrowninsoilextractednutrients