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Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions

BACKGROUND: Global food supply is highly dependent on field crop production that is currently severely threatened by changing climate, poor soil quality, abiotic, and biotic stresses. For instance, one of the major challenges to sustainable crop production in most developing countries is limited nit...

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Autores principales: Mburu, Simon W., Koskey, Gilbert, Njeru, Ezekiel M., Ombori, Omwoyo, Maingi, John, Kimiti, Jacinta M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9294079/
https://www.ncbi.nlm.nih.gov/pubmed/35849206
http://dx.doi.org/10.1186/s43141-022-00386-5
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author Mburu, Simon W.
Koskey, Gilbert
Njeru, Ezekiel M.
Ombori, Omwoyo
Maingi, John
Kimiti, Jacinta M.
author_facet Mburu, Simon W.
Koskey, Gilbert
Njeru, Ezekiel M.
Ombori, Omwoyo
Maingi, John
Kimiti, Jacinta M.
author_sort Mburu, Simon W.
collection PubMed
description BACKGROUND: Global food supply is highly dependent on field crop production that is currently severely threatened by changing climate, poor soil quality, abiotic, and biotic stresses. For instance, one of the major challenges to sustainable crop production in most developing countries is limited nitrogen in the soil. Symbiotic nitrogen fixation of legumes such as soybean (Glycine max (L.) Merril) with rhizobia plays a crucial role in supplying nitrogen sufficient to maintain good crop productivity. Characterization of indigenous bradyrhizobia is a prerequisite in the selection and development of effective bioinoculants. In view of this, bradyrhizobia were isolated from soybean nodules in four agro-climatic zones of eastern Kenya (Embu Upper Midland Zone, Embu Lower Midland Zone, Tharaka Upper Midland Zone, and Tharaka Lower Midland Zone) using two soybean varieties (SB8 and SB126). The isolates were characterized using biochemical, morphological, and genotypic approaches. DNA fingerprinting was carried out using 16S rRNA gene and restricted by enzymes HaeIII, Msp1, and EcoRI.  RESULTS: Thirty-eight (38) bradyrhizobia isolates obtained from the trapping experiments were placed into nine groups based on their morphological and biochemical characteristics. Most (77%) of the isolates had characteristics of fast-grower bradyrhizobia while 23% were slow-growers. Restriction digest revealed significant (p < 0.015) variation within populations and not among the agro-climatic zones based on analysis of molecular variance. Principal coordinate analysis demonstrated sympatric speciation of indigenous bradyrhizobia isolates. Embu Upper Midland Zone bradyrhizobia isolates had the highest polymorphic loci (80%) and highest genetic diversity estimates (H’ = 0.419) compared to other agro-climatic zones. CONCLUSION: The high diversity of bradyrhizobia isolates depicts a valuable genetic resource for selecting more effective and competitive strains to improve promiscuous soybean production at a low cost through biological nitrogen fixation.
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spelling pubmed-92940792022-08-09 Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions Mburu, Simon W. Koskey, Gilbert Njeru, Ezekiel M. Ombori, Omwoyo Maingi, John Kimiti, Jacinta M. J Genet Eng Biotechnol Research BACKGROUND: Global food supply is highly dependent on field crop production that is currently severely threatened by changing climate, poor soil quality, abiotic, and biotic stresses. For instance, one of the major challenges to sustainable crop production in most developing countries is limited nitrogen in the soil. Symbiotic nitrogen fixation of legumes such as soybean (Glycine max (L.) Merril) with rhizobia plays a crucial role in supplying nitrogen sufficient to maintain good crop productivity. Characterization of indigenous bradyrhizobia is a prerequisite in the selection and development of effective bioinoculants. In view of this, bradyrhizobia were isolated from soybean nodules in four agro-climatic zones of eastern Kenya (Embu Upper Midland Zone, Embu Lower Midland Zone, Tharaka Upper Midland Zone, and Tharaka Lower Midland Zone) using two soybean varieties (SB8 and SB126). The isolates were characterized using biochemical, morphological, and genotypic approaches. DNA fingerprinting was carried out using 16S rRNA gene and restricted by enzymes HaeIII, Msp1, and EcoRI.  RESULTS: Thirty-eight (38) bradyrhizobia isolates obtained from the trapping experiments were placed into nine groups based on their morphological and biochemical characteristics. Most (77%) of the isolates had characteristics of fast-grower bradyrhizobia while 23% were slow-growers. Restriction digest revealed significant (p < 0.015) variation within populations and not among the agro-climatic zones based on analysis of molecular variance. Principal coordinate analysis demonstrated sympatric speciation of indigenous bradyrhizobia isolates. Embu Upper Midland Zone bradyrhizobia isolates had the highest polymorphic loci (80%) and highest genetic diversity estimates (H’ = 0.419) compared to other agro-climatic zones. CONCLUSION: The high diversity of bradyrhizobia isolates depicts a valuable genetic resource for selecting more effective and competitive strains to improve promiscuous soybean production at a low cost through biological nitrogen fixation. Springer Berlin Heidelberg 2022-07-18 /pmc/articles/PMC9294079/ /pubmed/35849206 http://dx.doi.org/10.1186/s43141-022-00386-5 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research
Mburu, Simon W.
Koskey, Gilbert
Njeru, Ezekiel M.
Ombori, Omwoyo
Maingi, John
Kimiti, Jacinta M.
Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title_full Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title_fullStr Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title_full_unstemmed Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title_short Genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
title_sort genetic and phenotypic diversity of microsymbionts nodulating promiscuous soybeans from different agro-climatic conditions
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9294079/
https://www.ncbi.nlm.nih.gov/pubmed/35849206
http://dx.doi.org/10.1186/s43141-022-00386-5
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