Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia

Abstract Rhizobia are legume specific, and they need to be characterized by different methods. This study assessed the nodulation potential and phenotypic diversity of rhizobia nodulating cowpea [Vigna unguiculata (L.) Walp.] isolated from major growing areas of Ethiopia. From 30 soil samples, 28 (9...

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Main Authors: Erana Kebede, Berhanu Amsalu, Anteneh Argaw, Solomon Tamiru
Format: Article
Language:English
Published: Wiley 2022-01-01
Series:Agrosystems, Geosciences & Environment
Online Access:https://doi.org/10.1002/agg2.20308
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author Erana Kebede
Berhanu Amsalu
Anteneh Argaw
Solomon Tamiru
author_facet Erana Kebede
Berhanu Amsalu
Anteneh Argaw
Solomon Tamiru
author_sort Erana Kebede
collection DOAJ
description Abstract Rhizobia are legume specific, and they need to be characterized by different methods. This study assessed the nodulation potential and phenotypic diversity of rhizobia nodulating cowpea [Vigna unguiculata (L.) Walp.] isolated from major growing areas of Ethiopia. From 30 soil samples, 28 (93.3%) samples induced nodulation. Twenty‐eight isolates obtained from nodulated plants were evaluated using presumptive tests and different phenotypic characteristics. On yeast extract mannitol agar (YEMA) containing Congo red (CR), the isolates produced colony colors that were whitish to pale pink. All isolates showed no growth on peptone glucose agar and the isolates were capable of growing on ketolactose medium but did not turn the media color to yellow. All the isolates were also confirmed to be gram‐negative, rod‐shaped, and nonspore‐forming. The colony texture study revealed that 78.57% of the isolates had a large mucoid colony, whereas 21.43% exhibited a large watery colony texture with diameters ranging between 1 and 5 mm. Depending on the colony color on YEMA containing bromothymol blue, 22 (78.57%) isolates were slow growing, whereas six (21.43%) isolates were fast‐growing rhizobia. The cluster analysis based on phenotypic characteristics revealed a grouping of the isolates into two clusters at a similarity level of 75% and six further subclusters at a similarity level of ∼91%, indicating variations and diversity among the isolates. Overall, this study revealed significant variations among the cowpea nodulating rhizobial isolates and suggested that the soils of Ethiopia harbor populations of phenotypically diverse isolates. A further test to confirm these findings using genetic characterization and inclusion of reference strain is highly recommended.
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spelling doaj.art-bb8646817e3a4a3e9cb0c3ad722929de2022-12-22T04:41:27ZengWileyAgrosystems, Geosciences & Environment2639-66962022-01-0154n/an/a10.1002/agg2.20308Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of EthiopiaErana Kebede0Berhanu Amsalu1Anteneh Argaw2Solomon Tamiru3School of Plant Sciences, College of Agriculture and Environmental Sciences Haramaya Univ. Dire Dawa EthiopiaMelkassa Agricultural Research Center Ethiopian Institute of Agricultural Research Adama EthiopiaSchool of Natural Resources Management and Environmental Sciences, College of Agriculture and Environmental Sciences Haramaya Univ. Dire Dawa EthiopiaSchool of Natural Resources Management and Environmental Sciences, College of Agriculture and Environmental Sciences Haramaya Univ. Dire Dawa EthiopiaAbstract Rhizobia are legume specific, and they need to be characterized by different methods. This study assessed the nodulation potential and phenotypic diversity of rhizobia nodulating cowpea [Vigna unguiculata (L.) Walp.] isolated from major growing areas of Ethiopia. From 30 soil samples, 28 (93.3%) samples induced nodulation. Twenty‐eight isolates obtained from nodulated plants were evaluated using presumptive tests and different phenotypic characteristics. On yeast extract mannitol agar (YEMA) containing Congo red (CR), the isolates produced colony colors that were whitish to pale pink. All isolates showed no growth on peptone glucose agar and the isolates were capable of growing on ketolactose medium but did not turn the media color to yellow. All the isolates were also confirmed to be gram‐negative, rod‐shaped, and nonspore‐forming. The colony texture study revealed that 78.57% of the isolates had a large mucoid colony, whereas 21.43% exhibited a large watery colony texture with diameters ranging between 1 and 5 mm. Depending on the colony color on YEMA containing bromothymol blue, 22 (78.57%) isolates were slow growing, whereas six (21.43%) isolates were fast‐growing rhizobia. The cluster analysis based on phenotypic characteristics revealed a grouping of the isolates into two clusters at a similarity level of 75% and six further subclusters at a similarity level of ∼91%, indicating variations and diversity among the isolates. Overall, this study revealed significant variations among the cowpea nodulating rhizobial isolates and suggested that the soils of Ethiopia harbor populations of phenotypically diverse isolates. A further test to confirm these findings using genetic characterization and inclusion of reference strain is highly recommended.https://doi.org/10.1002/agg2.20308
spellingShingle Erana Kebede
Berhanu Amsalu
Anteneh Argaw
Solomon Tamiru
Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
Agrosystems, Geosciences & Environment
title Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
title_full Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
title_fullStr Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
title_full_unstemmed Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
title_short Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia
title_sort nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of ethiopia
url https://doi.org/10.1002/agg2.20308
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