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Sarkar A, Fwanyanga FM, Horn LN, Welzel S, Diederichs M, Kerk LJ, Zimmermann M, Reinhold-Hurek B. Towards inoculant development for Bambara groundnut ( Vigna subterranean (L.) Verdc) pulse crop production in Namibia. FRONTIERS IN PLANT SCIENCE 2023; 14:1270356. [PMID: 37965028 PMCID: PMC10641001 DOI: 10.3389/fpls.2023.1270356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/04/2023] [Indexed: 11/16/2023]
Abstract
Introduction The globally expanding population, together with climate change, poses a risk to the availability of food for humankind. Bambara groundnut (BGN) (Vigna subterranea (L.) Verdc) is a neglected, relatively drought-tolerant native legume of Sub-Saharan Africa that has the potential to become a successful food crop because of its nutritional quality and climate-smart features. Nitrogen fixation from root nodule symbiosis with climate-adapted rhizobial symbionts can contribute nitrogen and organic material in nutrient-poor soil and improve yields. However, high soil temperature and drought often reduce the abundance of native rhizobia in such soil. Therefore, the formulation of climate-smart biofertilizers has the potential to improve the farming of BGN at a low cost in a sustainable manner. Method The effect of seven Bradyrhizobium spp. strains native to Namibia, including B. vignae and B. subterraneum, were tested on three Namibian BGN varieties (red, brown, cream) in greenhouse pot experiments in Namibia, using soil from the target region of Kavango. Each variety was treated with a mixed inoculant consisting of seven preselected strains ("MK") as well as with one promising single inoculant strain. Results The results revealed that in all three varieties, the two inoculants (mixed or single) outperformed the non-inoculated cultivars in terms of shoot dry weight by up to 70%; the mixed inoculant treatment performed significantly better (p < 0.05) in all cases compared to the single inoculant used. To test whether the inoculant strains were established in root nodules, they were identified by sequence analysis. In many cases, the indigenous strains of Kavango soil outcompeted the inoculant strains of the mix for nodule occupancy, depending on the BGN variety. As a further preselection, each of the individual strains of the mix was used to inoculate the three varieties under sterile conditions in a phytotron. The agronomic trait and root nodulation response of the host plant inoculations strongly differed with the BGN variety. Even competitiveness in nodule occupancy without involving any indigenous strains from soil differed and depended strictly on the variety. Discussion Severe differences in symbiont-plant interactions appear to occur in BGN depending on the plant variety, demanding for coupling of breeding efforts with selecting efficient inoculant strains.
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Affiliation(s)
- Abhijit Sarkar
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Felicitas M. Fwanyanga
- Zero Emissions Research Initiative, Multi-disciplinary Research Services, University of Namibia, Windhoek, Namibia
| | - Lydia N. Horn
- Zero Emissions Research Initiative, Multi-disciplinary Research Services, University of Namibia, Windhoek, Namibia
| | - Sina Welzel
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Marco Diederichs
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Luca Jonas Kerk
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Meret Zimmermann
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Barbara Reinhold-Hurek
- CBIB Center for Biomolecular Interactions Bremen, Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
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Claassens R, Venter SN, Beukes CW, Stępkowski T, Chan WY, Steenkamp ET. Bradyrhizobium xenonodulans sp. nov. isolated from nodules of Australian Acacia species invasive to South Africa. Syst Appl Microbiol 2023; 46:126452. [PMID: 37634485 DOI: 10.1016/j.syapm.2023.126452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/29/2023]
Abstract
A genealogical concordance approach was used to delineate strains isolated from Acacia dealbata and Acacia mearnsii root nodules in South Africa. These isolates form part of Bradyrhizobium based on 16S rRNA sequence similarity. Phylogenetic analysis of six housekeeping genes (atpD, dnaK, glnII, gyrB, recA and rpoB) confirmed that these isolates represent a novel species, while pairwise average nucleotide identity (ANIb) calculations with the closest type strains (B. cosmicum 58S1T, B. betae PL7HG1T, B. ganzhouense CCBAU 51670 T, B. cytisi CTAW11T and B. rifense CTAW71T) resulted in values well below 95-96%. We further performed phenotypic tests which revealed that there are high levels of intraspecies variation, while an additional analysis of the nodA and nifD loci indicated that the symbiotic loci of the strains are closely related to those of Bradyrhizobium isolates with an Australian origin. Strain 14ABT (=LMG 31415 T = SARCC-753 T) is designated as the type strain of the novel species for which we propose the name Bradyrhizobium xenonodulans sp. nov.
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Affiliation(s)
- Ricu Claassens
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, Gauteng, South Africa
| | - Stephanus N Venter
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, Gauteng, South Africa
| | | | - Tomasz Stępkowski
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Poland
| | - Wai Y Chan
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, Gauteng, South Africa; Right to Care, Centurion, Gauteng, South Africa
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, Gauteng, South Africa.
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Rasche L, Becker JN, Chimwamurombe P, Eschenbach A, Gröngröft A, Jeong J, Luther-Mosebach J, Reinhold-Hurek B, Sarkar A, Schneider UA. Exploring the benefits of inoculated cowpeas under different climatic conditions in Namibia. Sci Rep 2023; 13:11761. [PMID: 37474671 PMCID: PMC10359254 DOI: 10.1038/s41598-023-38949-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 07/18/2023] [Indexed: 07/22/2023] Open
Abstract
Cowpeas (Vigna uniculata L. Walp) are grown by many smallholder farmers in sub-Saharan Africa for food and their ability to fix nitrogen even under stress. Their performance depends on the indigenous rhizobial strains that live in symbiotic association with the roots; it can be enhanced if the seeds are inoculated with more effective ones. Data of the effectiveness of the technique under a variety of climatic conditions is rare. Here, we thus use a model to upscale two field experiments conducted in Namibia to include different climate change scenarios. The simulations show that non-inoculated cowpeas have mean yields of 0.5 t/ha and inoculated cowpeas 1 t/ha. If climatic conditions are favorable (cool and wet), estimated yield differences increase to over 1 t/ha. In dry years (< 200 mm), the average yield difference is only 0.1 t/ha. In the far future (2080-2100), instances of dry and hot years will increase. Using inoculated cowpea seeds instead of non-inoculated ones thus does not benefit farmers as much then as in the near future (2030-2050). In conclusion, using cowpea seeds inoculated with an efficient rhizobial strain can significantly increase yields under varying climatic conditions, but yield advantages decrease markedly in very dry and hot years.
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Affiliation(s)
- Livia Rasche
- Research Unit Sustainability and Climate Risks, Universität Hamburg, Grindelberg 5, 20144, Hamburg, Germany.
| | - Joscha N Becker
- Institute of Soil Science, Universität Hamburg, Allende-Platz 2, 20146, Hamburg, Germany
| | - Percy Chimwamurombe
- Department of Natural and Applied Sciences, Namibia University of Science and Technology, Brahms St, Windhoek, Namibia
| | - Annette Eschenbach
- Institute of Soil Science, Universität Hamburg, Allende-Platz 2, 20146, Hamburg, Germany
| | - Alexander Gröngröft
- Institute of Soil Science, Universität Hamburg, Allende-Platz 2, 20146, Hamburg, Germany
- Department of Natural and Applied Sciences, Namibia University of Science and Technology, Brahms St, Windhoek, Namibia
| | - Jihye Jeong
- Research Unit Sustainability and Climate Risks, Universität Hamburg, Grindelberg 5, 20144, Hamburg, Germany
| | - Jona Luther-Mosebach
- Institute of Soil Science, Universität Hamburg, Allende-Platz 2, 20146, Hamburg, Germany
| | - Barbara Reinhold-Hurek
- Research Group Molecular Plant-Microbe Interactions, University of Bremen, Loebener Str. 5, 28359, Bremen, Germany
| | - Abhijit Sarkar
- Research Group Molecular Plant-Microbe Interactions, University of Bremen, Loebener Str. 5, 28359, Bremen, Germany
| | - Uwe A Schneider
- Research Unit Sustainability and Climate Risks, Universität Hamburg, Grindelberg 5, 20144, Hamburg, Germany
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Jemo M, Devkota KP, Epule TE, Chfadi T, Moutiq R, Hafidi M, Silatsa FBT, Jibrin JM. Exploring the potential of mapped soil properties, rhizobium inoculation, and phosphorus supplementation for predicting soybean yield in the savanna areas of Nigeria. FRONTIERS IN PLANT SCIENCE 2023; 14:1120826. [PMID: 37113594 PMCID: PMC10126304 DOI: 10.3389/fpls.2023.1120826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Rapid and accurate soybean yield prediction at an on-farm scale is important for ensuring sustainable yield increases and contributing to food security maintenance in Nigeria. We used multiple approaches to assess the benefits of rhizobium (Rh) inoculation and phosphorus (P) fertilization on soybean yield increase and profitability from large-scale conducted trials in the savanna areas of Nigeria [i.e., the Sudan Savanna (SS), Northern Guinea Savanna (NGS), and Southern Guinea Savanna (SGS)]. Soybean yield results from the established trials managed by farmers with four treatments (i.e., the control without inoculation and P fertilizer, Rh inoculation, P fertilizer, and Rh + P combination treatments) were predicted using mapped soil properties and weather variables in ensemble machine-learning techniques, specifically the conditional inference regression random forest (RF) model. Using the IMPACT model, scenario analyses were employed to simulate long-term adoption impacts on national soybean trade and currency. Our study found that yields of the Rh + P combination were consistently higher than the control in the three agroecological zones. Average yield increases were 128%, 111%, and 162% higher in the Rh + P combination compared to the control treatment in the SS, NGS, and SGS agroecological zones, respectively. The NGS agroecological zone showed a higher yield than SS and SGS. The highest training coefficient of determination (R2 = 0.75) for yield prediction was from the NGS dataset, and the lowest coefficient (R2 = 0.46) was from the SS samples. The results from the IMPACT model showed a reduction of 10% and 22% for the low (35% adoption scenario) and high (75% adoption scenario) soybean imports from 2029 in Nigeria, respectively. A significant reduction in soybean imports is feasible if the Rh + P inputs are large-scaled implemented at the on-farm field and massively adopted by farmers in Nigeria.
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Affiliation(s)
- Martin Jemo
- AgroBiosciences Program, College for Sustainable Agriculture and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Bengeurir, Morocco
| | - Krishna Prasad Devkota
- Soil, Water, and Agronomy (SWA) Program, International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat-institute, Rabat, Morocco
| | - Terence Epule Epule
- International Water Research Institute (IWRI), College for Sustainable Agriculture and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Bengeurir, Morocco
| | - Tarik Chfadi
- International Water Research Institute (IWRI), College for Sustainable Agriculture and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Bengeurir, Morocco
| | - Rkia Moutiq
- National Institute of Agronomical Research (INRA), Regional Center of Kenitra, Kenitra, Morocco
| | - Mohamed Hafidi
- AgroBiosciences Program, College for Sustainable Agriculture and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Bengeurir, Morocco
- Cadi Ayad University, Laboratory of Microbial Biotechnologies, Agrosciences and Environment, Faculty of Science Semlalia, Marrakesh, Morocco
| | - Francis B. T. Silatsa
- Center of Excellence for Soil and Fertilizer Research in Africa (CESFRA), College for Sustainable Agriculture and Environmental Sciences, Mohammed VI Polytechnic University (UM6P), Benguerir, Morocco
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Xavier GR, Jesus EDC, Dias A, Coelho MRR, Molina YC, Rumjanek NG. Contribution of Biofertilizers to Pulse Crops: From Single-Strain Inoculants to New Technologies Based on Microbiomes Strategies. PLANTS (BASEL, SWITZERLAND) 2023; 12:954. [PMID: 36840302 PMCID: PMC9962295 DOI: 10.3390/plants12040954] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Pulses provide distinct health benefits due to their low fat content and high protein and fiber contents. Their grain production reaches approximately 93,210 × 103 tons per year. Pulses benefit from the symbiosis with atmospheric N2-fixing bacteria, which increases productivity and reduces the need for N fertilizers, thus contributing to mitigation of environmental impact mitigation. Additionally, the root region harbors a rich microbial community with multiple traits related to plant growth promotion, such as nutrient increase and tolerance enhancement to abiotic or biotic stresses. We reviewed the eight most common pulses accounting for almost 90% of world production: common beans, chickpeas, peas, cowpeas, mung beans, lentils, broad beans, and pigeon peas. We focused on updated information considering both single-rhizobial inoculation and co-inoculation with plant growth-promoting rhizobacteria. We found approximately 80 microbial taxa with PGPR traits, mainly Bacillus sp., B. subtilis, Pseudomonas sp., P. fluorescens, and arbuscular mycorrhizal fungi, and that contributed to improve plant growth and yield under different conditions. In addition, new data on root, nodule, rhizosphere, and seed microbiomes point to strategies that can be used to design new generations of biofertilizers, highlighting the importance of microorganisms for productive pulse systems.
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Affiliation(s)
| | | | - Anelise Dias
- Departamento de Fitotecnia, Instituto de Agronomia, Universidade Federal Rural do Rio de Janeiro, UFRRJ, Rodovia BR-465, Km 7, Seropédica 23890-000, RJ, Brazil
| | | | - Yulimar Castro Molina
- Programa de Pós-graduação em Microbiologia Agrícola, Universidade Federal de Lavras, UFLA, Trevo Rotatório Professor Edmir Sá Santos, Lavras 37203-202, MG, Brazil
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Floc'h JB, Hamel C, Laterrière M, Tidemann B, St-Arnaud M, Hijri M. Inter-Kingdom Networks of Canola Microbiome Reveal Bradyrhizobium as Keystone Species and Underline the Importance of Bulk Soil in Microbial Studies to Enhance Canola Production. MICROBIAL ECOLOGY 2022; 84:1166-1181. [PMID: 34727198 DOI: 10.1007/s00248-021-01905-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
The subterranean microbiota of plants is of great importance for plant growth and health, as root-associated microbes can perform crucial ecological functions. As the microbial environment of roots is extremely diverse, identifying keystone microorganisms in plant roots, rhizosphere, and bulk soil is a necessary step towards understanding the network of influence within the microbial community associated with roots and enhancing its beneficial elements. To target these hot spots of microbial interaction, we used inter-kingdom network analysis on the canola growth phase of a long-term cropping system diversification experiment conducted at four locations in the Canadian Prairies. Our aims were to verify whether bacterial and fungal communities of canola roots, rhizosphere, and bulk soil are related and influenced by diversification of the crop rotation system; to determine whether there are common or specific core fungi and bacteria in the roots, rhizosphere, and bulk soil under canola grown in different environments and with different levels of cropping system diversification; and to identify hub taxa at the inter-kingdom level that could play an important ecological role in the microbiota of canola. Our results showed that fungi were influenced by crop diversification, which was not the case on bacteria. We found no core microbiota in canola roots but identified three core fungi in the rhizosphere, one core mycobiota in the bulk soil, and one core bacterium shared by the rhizosphere and bulk soil. We identified two bacterial and one fungal hub taxa in the inter-kingdom networks of the canola rhizosphere, and one bacterial and two fungal hub taxa in the bulk soil. Among these inter-kingdom hub taxa, Bradyrhizobium sp. and Mortierella sp. are particularly influential on the microbial community and the plant. To our knowledge, this is the first inter-kingdom network analysis utilized to identify hot spots of interaction in canola microbial communities.
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Affiliation(s)
- Jean-Baptiste Floc'h
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 East, Sherbrooke Street, Montréal, QC, H1X 2B2, Canada
- Quebec Research and Development Centre, Agriculture and Agri-Food Canada, Quebec City, QC, Canada
| | - Chantal Hamel
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 East, Sherbrooke Street, Montréal, QC, H1X 2B2, Canada
- Quebec Research and Development Centre, Agriculture and Agri-Food Canada, Quebec City, QC, Canada
| | - Mario Laterrière
- Quebec Research and Development Centre, Agriculture and Agri-Food Canada, Quebec City, QC, Canada
| | - Breanne Tidemann
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, Canada
| | - Marc St-Arnaud
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 East, Sherbrooke Street, Montréal, QC, H1X 2B2, Canada
| | - Mohamed Hijri
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 East, Sherbrooke Street, Montréal, QC, H1X 2B2, Canada.
- African Genome Center, Mohammed VI Polytechnic University (UM6P), Lot 660, Hay Moulay Rachid, 43150, Ben Guerir, Morocco.
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Adjei JA, Aserse AA, Yli-Halla M, Ahiabor BDK, Abaidoo RC, Lindstrom K. Phylogenetically diverse Bradyrhizobium genospecies nodulate Bambara groundnut (Vigna subterranea L. Verdc) and soybean (Glycine max L. Merril) in the northern savanna zones of Ghana. FEMS Microbiol Ecol 2022; 98:fiac043. [PMID: 35404419 PMCID: PMC9329091 DOI: 10.1093/femsec/fiac043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/30/2022] [Accepted: 04/08/2022] [Indexed: 11/25/2022] Open
Abstract
A total of 102 bacterial strains isolated from nodules of three Bambara groundnut and one soybean cultivars grown in nineteen soil samples collected from northern Ghana were characterized using multilocus gene sequence analysis. Based on a concatenated sequence analysis (glnII-rpoB-recA-gyrB-atpD-dnaK), 54 representative strains were distributed in 12 distinct lineages, many of which were placed mainly in the Bradyrhizobium japonicum and Bradyrhizobium elkanii supergroups. Twenty-four of the 54 representative strains belonged to seven putative novel species, while 30 were conspecific with four recognized Bradyrhizobium species. The nodA phylogeny placed all the representative strains in the cosmopolitan nodA clade III. The strains were further separated in seven nodA subclusters with reference strains mainly of African origin. The nifH phylogeny was somewhat congruent with the nodA phylogeny, but both symbiotic genes were mostly incongruent with the core housekeeping gene phylogeny indicating that the strains acquired their symbiotic genes horizontally from distantly related Bradyrhizobium species. Using redundancy analysis, the distribution of genospecies was found to be influenced by the edaphic factors of the respective sampling sites. In general, these results mainly underscore the high genetic diversity of Bambara groundnut-nodulating bradyrhizobia in Ghanaian soils and suggest a possible vast resource of adapted inoculant strains.
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Affiliation(s)
- Josephine A Adjei
- Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
- Faculty of Biological and Environmental Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
- Council for Scientific and Industrial Research, Savanna Agricultural Research Institute, PO Box 52, Tamale, Ghana
| | - Aregu A Aserse
- Faculty of Biological and Environmental Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Markku Yli-Halla
- Department of Agricultural Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Benjamin D K Ahiabor
- Council for Scientific and Industrial Research, Savanna Agricultural Research Institute, PO Box 52, Tamale, Ghana
| | - Robert C Abaidoo
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
- International Institute of Tropical Agriculture, PMB 5320, Ibadan, Nigeria
| | - Kristina Lindstrom
- Faculty of Biological and Environmental Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
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Arashida H, Odake H, Sugawara M, Noda R, Kakizaki K, Ohkubo S, Mitsui H, Sato S, Minamisawa K. Evolution of rhizobial symbiosis islands through insertion sequence-mediated deletion and duplication. THE ISME JOURNAL 2022; 16:112-121. [PMID: 34272493 PMCID: PMC8692435 DOI: 10.1038/s41396-021-01035-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 05/27/2021] [Accepted: 06/03/2021] [Indexed: 11/08/2022]
Abstract
Symbiosis between organisms influences their evolution via adaptive changes in genome architectures. Immunity of soybean carrying the Rj2 allele is triggered by NopP (type III secretion system [T3SS]-dependent effector), encoded by symbiosis island A (SymA) in B. diazoefficiens USDA122. This immunity was overcome by many mutants with large SymA deletions that encompassed T3SS (rhc) and N2 fixation (nif) genes and were bounded by insertion sequence (IS) copies in direct orientation, indicating homologous recombination between ISs. Similar deletion events were observed in B. diazoefficiens USDA110 and B. japonicum J5. When we cultured a USDA122 strain with a marker gene sacB inserted into the rhc gene cluster, most sucrose-resistant mutants had deletions in nif/rhc gene clusters, similar to the mutants above. Some deletion mutants were unique to the sacB system and showed lower competitive nodulation capability, indicating that IS-mediated deletions occurred during free-living growth and the host plants selected the mutants. Among 63 natural bradyrhizobial isolates, 2 possessed long duplications (261-357 kb) harboring nif/rhc gene clusters between IS copies in direct orientation via homologous recombination. Therefore, the structures of symbiosis islands are in a state of flux via IS-mediated duplications and deletions during rhizobial saprophytic growth, and host plants select mutualistic variants from the resultant pools of rhizobial populations. Our results demonstrate that homologous recombination between direct IS copies provides a natural mechanism generating deletions and duplications on symbiosis islands.
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Affiliation(s)
- Haruka Arashida
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Haruka Odake
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Masayuki Sugawara
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Ryota Noda
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Kaori Kakizaki
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Satoshi Ohkubo
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Hisayuki Mitsui
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Shusei Sato
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Kiwamu Minamisawa
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan.
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Ajilogba CF, Olanrewaju OS, Babalola OO. Improving Bambara Groundnut Production: Insight Into the Role of Omics and Beneficial Bacteria. FRONTIERS IN PLANT SCIENCE 2022; 13:836133. [PMID: 35310649 PMCID: PMC8929175 DOI: 10.3389/fpls.2022.836133] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/04/2022] [Indexed: 05/05/2023]
Abstract
With the rise in the world population, environmental hazards caused by chemical fertilizers, and a decrease in food supply due to global climate change, food security has become very pertinent. In addition, considerable parts of agriculture lands have been lost to urbanization. It has therefore been projected that at the present rate of population increase coupled with the other mentioned factors, available food will not be enough to feed the world. Hence, drastic approach is needed to improve agriculture output as well as human sustainability. Application of environmentally sustainable approach, such as the use of beneficial microbes, and improved breeding of underutilized legumes are one of the proposed sustainable ways of achieving food security. Microbiome-assisted breeding in underutilized legumes is an untapped area with great capabilities to improve food security. Furthermore, revolution in genomics adaptation to crop improvement has changed the approach from conventional breeding to more advanced genomic-assisted breeding on the host plant and its microbiome. The use of rhizobacteria is very important to improving crop yield, especially rhizobacteria from legumes like Bambara groundnut (BGN). BGN is an important legume in sub-Saharan Africa with high ability to tolerate drought and thrive well in marginalized soils. BGN and its interaction with various rhizobacteria in the soil could play a vital role in crop production and protection. This review focus on the importance of genomics application to BGN and its microbiome with the view of setting a potential blueprint for improved BGN breeding through integration of beneficial bacteria.
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Affiliation(s)
- Caroline Fadeke Ajilogba
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Science, North-West University, Mafikeng, South Africa
- Division of Agrometeorology, Agricultural Research Council, Natural Resources and Engineering, Pretoria, South Africa
| | - Oluwaseyi Samuel Olanrewaju
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Science, North-West University, Mafikeng, South Africa
| | - Olubukola Oluranti Babalola
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Science, North-West University, Mafikeng, South Africa
- *Correspondence: Olubukola Oluranti Babalola,
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10
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Dlamini ST, Jaiswal SK, Mohammed M, Dakora FD. Studies of Phylogeny, Symbiotic Functioning and Ecological Traits of Indigenous Microsymbionts Nodulating Bambara Groundnut (Vigna subterranea L. Verdc) in Eswatini. MICROBIAL ECOLOGY 2021; 82:688-703. [PMID: 33606087 DOI: 10.1007/s00248-021-01684-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Rhizobial microsymbionts of grain legumes are ubiquitous in soils and exhibit a wide range of diversity with respect to colony morphology, genetic variability, biochemical characteristics, and phylogenetic relationships. This study assessed the phylogenetic positions of rhizobial microsymbionts of Bambara groundnut from Eswatini exhibiting variations in morpho-physiology, adaptive characteristics, and N2-fixing efficiency. The isolates' ERIC-PCR profiles revealed the presence of high genetic variation among them. These test isolates also exhibited differences in pH tolerance and IAA production. Multilocus sequence analysis based on the 16S rRNA, atpD, glnII, gyrB, and recA gene sequences of representative test isolates closely aligned them to the type strains of Bradyrhizobium arachidis, B. manausense, B. guangdongense, B. elkanii, and B. pachyrhizi. However, some isolates showed a high divergence from the known reference type strains, indicating that they may represent species yet to be properly characterized and described. Functional characterization in the glasshouse revealed that most of the isolates from the contrasting Agro-ecologies of Eswatini were efficient in N2 fixation, and therefore elicited greater stomatal conductance and photosynthetic rates in the homologous Bambara groundnut. Of the 75 isolates tested, 51% were more effective than the commercial Bradyrhizobium sp. strain CB756, with relative symbiotic effectiveness ranging from 138 to 308%. The findings of this study indicated that the analysis of housekeeping genes and functional traits of Bambara-nodulating microsymbionts can provide a clear view for understanding and predicting rhizobial community structure across environmental gradients.
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Affiliation(s)
- Sibusiso T Dlamini
- Department of Crop Sciences, Tshwane University of Technology, Pretoria, South Africa
| | - Sanjay K Jaiswal
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa.
| | - Mustapha Mohammed
- Department of Crop Sciences, Tshwane University of Technology, Pretoria, South Africa
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
| | - Felix D Dakora
- Department of Chemistry, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa.
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11
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Gnangui SLE, Fossou RK, Ebou A, Amon CER, Koua DK, Kouadjo CGZ, Cowan DA, Zézé A. The Rhizobial Microbiome from the Tropical Savannah Zones in Northern Côte d'Ivoire. Microorganisms 2021; 9:microorganisms9091842. [PMID: 34576737 PMCID: PMC8472840 DOI: 10.3390/microorganisms9091842] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/17/2021] [Accepted: 08/21/2021] [Indexed: 01/04/2023] Open
Abstract
Over the past decade, many projects have been initiated worldwide to decipher the composition and function of the soil microbiome, including the African Soil Microbiome (AfSM) project that aims at providing new insights into the presence and distribution of key groups of soil bacteria from across the African continent. In this national study, carried out under the auspices of the AfSM project, we assessed the taxonomy, diversity and distribution of rhizobial genera in soils from the tropical savannah zones in Northern Côte d’Ivoire. Genomic DNA extracted from seven sampled soils was analyzed by sequencing the V4-V5 variable region of the 16S rDNA using Illumina’s MiSeq platform. Subsequent bioinformatic and phylogenetic analyses showed that these soils harbored 12 out of 18 genera of Proteobacteria harboring rhizobia species validly published to date and revealed for the first time that the Bradyrhizobium genus dominates in tropical savannah soils, together with Microvirga and Paraburkholderia. In silico comparisons of different 16S rRNA gene variable regions suggested that the V5-V7 region could be suitable for differentiating rhizobia at the genus level, possibly replacing the use of the V4-V5 region. These data could serve as indicators for future rhizobial microbiome explorations and for land-use decision-making.
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Affiliation(s)
- Sara Laetitia Elphège Gnangui
- Laboratoire de Biotechnologies Végétale et Microbienne (LBVM), Unité Mixte de Recherche et d’Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro 1093, Côte d’Ivoire; (S.L.E.G.); (A.E.); (C.E.R.A.); (A.Z.)
| | - Romain Kouakou Fossou
- Laboratoire de Biotechnologies Végétale et Microbienne (LBVM), Unité Mixte de Recherche et d’Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro 1093, Côte d’Ivoire; (S.L.E.G.); (A.E.); (C.E.R.A.); (A.Z.)
- Correspondence:
| | - Anicet Ebou
- Laboratoire de Biotechnologies Végétale et Microbienne (LBVM), Unité Mixte de Recherche et d’Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro 1093, Côte d’Ivoire; (S.L.E.G.); (A.E.); (C.E.R.A.); (A.Z.)
- Équipe Bioinformatique, Département de Formation et de Recherche Agriculture et Ressources Animales, Institut National Polytechnique Félix Houphouët-Boigny, Yamoussoukro 1313, Côte d’Ivoire;
| | - Chiguié Estelle Raïssa Amon
- Laboratoire de Biotechnologies Végétale et Microbienne (LBVM), Unité Mixte de Recherche et d’Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro 1093, Côte d’Ivoire; (S.L.E.G.); (A.E.); (C.E.R.A.); (A.Z.)
| | - Dominique Kadio Koua
- Équipe Bioinformatique, Département de Formation et de Recherche Agriculture et Ressources Animales, Institut National Polytechnique Félix Houphouët-Boigny, Yamoussoukro 1313, Côte d’Ivoire;
| | - Claude Ghislaine Zaka Kouadjo
- Laboratoire Central de Biotechnologies, Centre National de la Recherche Agronomique, 01 Abidjan 1740, Côte d’Ivoire;
| | - Don A. Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa;
| | - Adolphe Zézé
- Laboratoire de Biotechnologies Végétale et Microbienne (LBVM), Unité Mixte de Recherche et d’Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro 1093, Côte d’Ivoire; (S.L.E.G.); (A.E.); (C.E.R.A.); (A.Z.)
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12
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Development of an Illumina-based analysis method to study bradyrhizobial population structure-case study on nitrogen-fixing rhizobia associating with cowpea or peanut. Appl Microbiol Biotechnol 2021; 105:6943-6957. [PMID: 34453562 DOI: 10.1007/s00253-021-11525-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/04/2021] [Accepted: 08/07/2021] [Indexed: 10/20/2022]
Abstract
Bradyrhizobia are Gram-negative soil bacteria that regroup a growing number of species. They are widespread in nature and recovered from various biomes that may be explained by a high genetic diversity in this genus. Among the numerous metabolic properties they can harbor, the nitrogen fixation resulting from the association with plants among which important crop legumes (soya bean, peanut, cowpea …) is of great interest, notably in a context of sustainable development. Metabarcoding is widely applied to study biodiversity from complex microbial communities. Here, we demonstrate that using a new species-specific and highly polymorphic 16S-23S rRNA intergenic spacer barcode, we could rapidly estimate the diversity of bradyrhizobial populations that associate with cowpea and peanut plants, two crop legumes of major interest in Senegal. Application of the method on indigenous bradyrhizobia associated with peanut and cowpea grown in soils collected in the center of the peanut basin shows that Bradyrhizobium vignae is a dominant symbiont. We also showed that the two plant species associate with distinct community profiles and that strains introduced by inoculation significantly modified the population structure with these two plants suggesting that application of elite strains as inoculants may well ensure optimized symbiotic performance. This approach may further be used to study the diversity of bradyrhizobia from contrasting agro-eco-climatic zones, to test whether the plant genotype influences the association outputs as well as to estimate the competitiveness for nodule occupancy and the fate of elite strains inoculated in the field.Key points• An amplicon sequencing approach targeting the Bradyrhizobium genus was developed.• Diversity of cowpea and peanut bradyrhizobia from cultivated soils was identified.• The method is well suited to test the competitiveness of defined Bradyrhizobium inoculants.
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13
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Muindi MM, Muthini M, Njeru EM, Maingi J. Symbiotic efficiency and genetic characterization of rhizobia and non rhizobial endophytes associated with cowpea grown in semi-arid tropics of Kenya. Heliyon 2021; 7:e06867. [PMID: 33997399 PMCID: PMC8093882 DOI: 10.1016/j.heliyon.2021.e06867] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/08/2020] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Cowpea (Vigna unguiculata (L.) Walp) is an important multipurpose legume crop grown in arid and semi-arid areas of sub-Saharan Africa. The crop associates with a wide diversity of high ecological value rhizobia bacteria, improving biological soil fertility and crop production. Here, we evaluated the symbiotic efficiency (SE) and genetic diversity of native rhizobia isolated from root nodules of cowpea genotypes cultivated in semi-arid areas of lower Eastern Kenya. Rhizobia trapping and SE experiments were done in the greenhouse while genetic diversity was evaluated based on 16S rRNA gene sequencing. Twenty morphologically distinct isolates representing a total of 94 isolates were used for genetic analysis. After 16S rRNA gene sequencing, the isolates closely resembled bacteria belonging to the genus Rhizobium, Paraburkholderia and non-rhizobial endophytes (Enterobacter, Strenotrophomonas and Pseudomonas). This study also reports for the first time the presence of an efficient native cowpea nodulating Beta-Rhizobia (Paraburkholderia phenoliruptrix BR3459a) in Africa. Symbiotic efficiency of the native rhizobia isolates varied (p < 0.0001) significantly. Remarkably, two isolates, M2 and M3 recorded higher SE of 82.49 % and 72.76 % respectively compared to the commercial strain Bradyrhizobium sp. USDA 3456 (67.68 %). Our results form an important step in the development of efficient microbial inoculum and sustainable food production.
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Affiliation(s)
- Mercy Martha Muindi
- Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - Morris Muthini
- Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - Ezekiel Mugendi Njeru
- Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
| | - John Maingi
- Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
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14
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Banasiewicz J, Granada CE, Lisboa BB, Grzesiuk M, Matuśkiewicz W, Bałka M, Schlindwein G, Vargas LK, Passaglia LMP, Stępkowski T. Diversity and phylogenetic affinities of Bradyrhizobium isolates from Pampa and Atlantic Forest Biomes. Syst Appl Microbiol 2021; 44:126203. [PMID: 33857759 DOI: 10.1016/j.syapm.2021.126203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/10/2021] [Accepted: 03/22/2021] [Indexed: 02/06/2023]
Abstract
In this work, we investigated Bradyrhizobium strains isolated from soils collected from the rhizosphere of native and exotic legumes species inhabiting two ecoclimatic zones - asubtropical-lowland pasture (Pampa Biome) and a volcanic plateau covered by Araucaria Moist Forests (Atlantic Forest Biome). The rhizobial strains were isolated from the nodules of seven native and one exotic legume species used as rhizobium traps. Single-gene (recA, glnII, dnaK) and combined-gene MLSA analyses (dnaK-glnII-gyrB-recA-rpoB) revealed that nearly 85% of the isolates clustered in B. elkanii supergroup, while the remaining (except for two isolates) in B. japonicum supergroup, albeit, in most cases, separately from the type strains of Bradyrhizobium species. As a symbiotic gene marker, a portion of nifD gene was sequenced for 194 strains. In the nifD-tree, an American branch III.3D (104 isolates), was the most numerous among the isolates. A significant portion of the isolates clustered in American groups; subclade III.4 (40 strains), Clade VII (3 strains), and a new Clade XX (4 strains). Most of the remaining strains belonged to a pantropical III.3C branch (39 isolates). On the other hand, identification of isolates belonging, respectively, to Clade I and Clade II may result of spreading of the Australian (Clade I) and European (Clade II) bradyrhizobia following the introduction of their legume hosts. Our study indicated that the American groups predominated in the symbiotic Bradyrhizobium communities in southern Brazil. However, there is a significant component of exotic lineages, resulting from the dispersal of pantropical Fabaceae taxa and the introduction of exotic legumes.
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Affiliation(s)
- Joanna Banasiewicz
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Camille E Granada
- Universidade do Vale do Taquari - UNIVATES, Rua Avelino Tallini, 171, 95900-000 Lajeado, RS, Brazil
| | - Bruno B Lisboa
- Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Rua Gonçalves Dias 570, 90130-060 Porto Alegre, RS, Brazil
| | - Małgorzata Grzesiuk
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Weronika Matuśkiewicz
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Mateusz Bałka
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Gilson Schlindwein
- Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Rua Gonçalves Dias 570, 90130-060 Porto Alegre, RS, Brazil
| | - Luciano K Vargas
- Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Rua Gonçalves Dias 570, 90130-060 Porto Alegre, RS, Brazil
| | - Luciane M P Passaglia
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul., Av. Bento Gonçalves, 9500, Caixa Postal 15.053, 91501-970 Porto Alegre, RS, Brazil
| | - Tomasz Stępkowski
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland.
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15
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Bünger W, Sarkar A, Grönemeyer JL, Zielinski J, Revermann R, Hurek T, Reinhold-Hurek B. Root Nodule Rhizobia From Undomesticated Shrubs of the Dry Woodlands of Southern Africa Can Nodulate Angolan Teak Pterocarpus angolensis, an Important Source of Timber. Front Microbiol 2021; 12:611704. [PMID: 33584615 PMCID: PMC7876412 DOI: 10.3389/fmicb.2021.611704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/06/2021] [Indexed: 11/17/2022] Open
Abstract
Pterocarpus angolensis, a leguminous tree native to the dry woodlands of Southern Africa, provides valuable timber, but is threatened by land conversion and overharvesting while showing limited natural regeneration. Nitrogen-fixing root nodule symbionts that could improve establishment of young seedlings have not yet been described. Therefore, we investigated the ability of P. angolensis to form nodules with a diverse range of rhizobia. In drought-prone areas under climate change with higher temperatures, inoculants that are heat-tolerant and adapted to these conditions are likely to be of advantage. Sources of bacterial isolates were roots of P. angolensis from nurseries in the Kavango region, other shrubs from this area growing near Pterocarpus such as Indigofera rautanenii, Desmodium barbatum, Chamaecrista sp., or shrubs from drought-prone areas in Namaqualand (Wiborgia monoptera, Leobordea digitata) or Kalahari (Indigofera alternans). Only slight protrusions were observed on P. angolensis roots, from which a non-nodulating Microbacterium sp. was isolated. Rhizobia that were isolated from nodules of other shrubs were affiliated to Bradyrhizobium ripae WR4T, Bradyrhizobium spp. (WR23/WR74/WR93/WR96), or Ensifer/Mesorhizobium (WR41/WR52). As many plant growth-promoting rhizobacteria (PGPR), nodule isolates produced siderophores and solubilized phosphate. Among them, only the Bradyrhizobium strains nodulated P. angolensis under controlled conditions in the laboratory. Isolates were further characterized by multilocus sequence analysis and were found to be distant from known Bradyrhizobium species. Among additional reference species tested for nodulation on P. angolensis, Bradyrhizobium vignae 7-2T and Bradyrhizobium namibiense 5-10T from the Kavango region of Namibia as well as Bradyrhizobium elkanii LMG6234T and Bradyrhizobium yuanmingense LMG21728T induced nitrogen-fixing nodules, while Bradyrhizobium diazoefficiens USDA110T and Bradyrhizobium tropiciagri SEMIA6148T did not. This suggests a broad microsymbiont range from Bradyrhizobium japonicum and B. elkanii lineages. Phylogenetic analysis of nodC genes indicated that nodulating bradyrhizobia did not belong to a specific symbiovar. Also, for I. rautanenii and Wiborgia, nodule isolates B. ripae WR4T or Mesorhizobium sp. WR52, respectively, were authenticated. Characterization of symbionts inducing effective root nodules in P. angolensis and other shrubs from Subsahara Africa (SSA) give insights in their symbiotic partners for the first time and might help in future to develop bioinoculants for young seedlings in nurseries, and for reforestation efforts in Southern Africa.
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Affiliation(s)
- Wiebke Bünger
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Abhijit Sarkar
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Jann Lasse Grönemeyer
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Janina Zielinski
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Rasmus Revermann
- Department of Biodiversity, Ecology and Evolution of Plants, Institute of Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
- Faculty of Natural Resources and Spatial Sciences, Namibia University of Science and Technology, Windhoek, Namibia
| | - Thomas Hurek
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Barbara Reinhold-Hurek
- Department of Microbe-Plant Interactions, CBIB (Center for Biomolecular Interactions Bremen), Faculty Biology and Chemistry, University of Bremen, Bremen, Germany
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Fossou RK, Pothier JF, Zézé A, Perret X. Bradyrhizobium ivorense sp. nov. as a potential local bioinoculant for Cajanus cajan cultures in Côte d'Ivoire. Int J Syst Evol Microbiol 2020; 70:1421-1430. [PMID: 32122457 PMCID: PMC7397250 DOI: 10.1099/ijsem.0.003931] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For many smallholder farmers of Sub-Saharan Africa, pigeonpea (Cajanus cajan) is an important crop to make ends meet. To ascertain the taxonomic status of pigeonpea isolates of Côte d’Ivoire previously identified as bradyrhizobia, a polyphasic approach was applied to strains CI-1BT, CI-14A, CI-19D and CI-41S. Phylogeny of 16S ribosomal RNA (rRNA) genes placed these nodule isolates in a separate lineage from current species of the B. elkanii super clade. In phylogenetic analyses of single and concatenated partial dnaK, glnII, gyrB, recA and rpoB sequences, the C. cajan isolates again formed a separate lineage, with strain CI-1BT sharing the highest sequence similarity (95.2 %) with B. tropiciagri SEMIA 6148T. Comparative genomic analyses corroborated the novel species status, with 86 % ANIb and 89 % ANIm as the highest average nucleotide identity (ANI) values with B. elkanii USDA 76T. Although CI-1BT, CI-14A, CI-19D and CI-41S shared similar phenotypic and metabolic properties, growth of CI-41S was slower in/on various media. Symbiotic efficacy varied significantly between isolates, with CI-1BT and CI-41S scoring on the C. cajan ‘Light-Brown’ landrace as the most and least proficient bacteria, respectively. Also proficient on Vigna radiata (mung bean), Vigna unguiculata (cowpea, niébé) and additional C. cajan cultivars, CI-1BT represents a potential bioinoculant adapted to local soil conditions and capable of fostering the growth of diverse legume crops in Côte d'Ivoire. Given the data presented here, we propose the 19 C. cajan isolates to belong to a novel species called Bradyrhizobium ivorense sp. nov., with CI-1BT (=CCOS 1862T=CCMM B1296T) as a type strain.
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Affiliation(s)
- Romain K Fossou
- Laboratoire de Biotechnologies Végétale et Microbienne, Unité Mixte de Recherche et d'Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro, Côte d'Ivoire.,Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Sciences III, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Joël F Pothier
- Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland
| | - Adolphe Zézé
- Laboratoire de Biotechnologies Végétale et Microbienne, Unité Mixte de Recherche et d'Innovation en Sciences Agronomiques et Génie Rural, Institut National Polytechnique Felix Houphouët-Boigny, Yamoussoukro, Côte d'Ivoire
| | - Xavier Perret
- Department of Botany and Plant Biology, Microbiology Unit, University of Geneva, Sciences III, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Characterization of Bradyrhizobium strains indigenous to Western Australia and South Africa indicates remarkable genetic diversity and reveals putative new species. Syst Appl Microbiol 2020; 43:126053. [PMID: 31937424 DOI: 10.1016/j.syapm.2020.126053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/30/2019] [Accepted: 01/01/2020] [Indexed: 01/01/2023]
Abstract
Bradyrhizobium are N2-fixing microsymbionts of legumes with relevant applications in agricultural sustainability, and we investigated the phylogenetic relationships of conserved and symbiotic genes of 21 bradyrhizobial strains. The study included strains from Western Australia (WA), isolated from nodules of Glycine spp. the country is one genetic center for the genus and from nodules of other indigenous legumes grown in WA, and strains isolated from forage Glycine sp. grown in South Africa. The 16S rRNA phylogeny divided the strains in two superclades, of B. japonicum and B. elkanii, but with low discrimination among the species. The multilocus sequence analysis (MLSA) with four protein-coding housekeeping genes (dnaK, glnII, gyrB and recA) pointed out seven groups as putative new species, two within the B. japonicum, and five within the B. elkanii superclades. The remaining eleven strains showed higher similarity with six species, B. lupini, B. liaoningense, B. yuanmingense, B. subterraneum, B. brasilense and B. retamae. Phylogenetic analysis of the nodC symbiotic gene clustered 13 strains in three different symbiovars (sv. vignae, sv. genistearum and sv. retamae), while seven others might compose new symbiovars. The genetic profiles of the strains evaluated by BOX-PCR revealed high intra- and interspecific diversity. The results point out the high level of diversity still to be explored within the Bradyrhizobium genus, and further studies might confirm new species and symbiovars.
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18
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Insights into the Phylogeny, Nodule Function, and Biogeographic Distribution of Microsymbionts Nodulating the Orphan Kersting's Groundnut [ Macrotyloma geocarpum (Harms) Marechal & Baudet] in African Soils. Appl Environ Microbiol 2019; 85:AEM.00342-19. [PMID: 30952658 PMCID: PMC6532025 DOI: 10.1128/aem.00342-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/23/2019] [Indexed: 02/06/2023] Open
Abstract
Kersting's groundnut [Macrotyloma geocarpum (Harms) Marechal & Baudet] is a neglected indigenous African legume adapted to growth in N-deficient soils due to its ability to fix atmospheric N2 via symbiosis with rhizobia. Despite its nutritional and medicinal uses, to date there is little information on the phylogeny and functional traits of its microsymbionts, aspects that are much needed for its conservation and improvement. This study explored the morphogenetic diversity, phylogenetic relationships, and N2-fixing efficiency of Kersting's groundnut rhizobial isolates from contrasting environments in Ghana, South Africa, and Mozambique. BOX-PCR fingerprinting revealed high diversity among the rhizobial populations, which was influenced by geographic origin. Of the 164 isolates evaluated, 130 BOX-PCR types were identified at a 70% similarity coefficient, indicating that they were not clones. Soil pH and mineral concentrations were found to influence the distribution of bradyrhizobial populations in African soils. Phylogenetic analysis of 16S rRNA genes and multilocus sequence analysis of protein-coding genes (atpD, glnII, gyrB, and rpoB) and symbiotic genes (nifH and nodC) showed that Kersting's groundnut is primarily nodulated by members of the genus Bradyrhizobium, which are closely related to Bradyrhizobium vignae 7-2T, Bradyrhizobium kavangense 14-3T, Bradyrhizobium subterraneum 58-2-1T, Bradyrhizobium pachyrhizi PAC48T, the type strain of Bradyrhizobium elkanii, and novel groups of Bradyrhizobium species. The bradyrhizobial populations identified exhibited high N2 fixation and induced greater nodulation, leaf chlorophyll concentration, and photosynthetic rates in their homologous host than did the 5 mM KNO3-fed plants and/or the commercial Bradyrhizobium sp. strain CB756, suggesting that they could be good candidates for inoculant formulations upon field testing.IMPORTANCE Rhizobia play important roles in agroecosystems, where they contribute to improving overall soil health through their symbiotic relationship with legumes. This study explored the microsymbionts nodulating Kersting's groundnut, a neglected orphan legume. The results revealed the presence of different bradyrhizobial populations with high N2-fixing efficiencies as the dominant symbionts of this legume across diverse agroecologies in Africa. Our findings represent a useful contribution to the literature in terms of the community of microsymbionts nodulating a neglected cultivated legume and its potential for elevation as a major food crop. The presence of potentially novel bradyrhizobial symbionts of Kersting's groundnut found in this study offers an opportunity for future studies to properly describe, characterize, and delineate these isolates functionally and phylogenetically for use in inoculant production to enhance food/nutritional security.
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Avontuur JR, Palmer M, Beukes CW, Chan WY, Coetzee MPA, Blom J, Stępkowski T, Kyrpides NC, Woyke T, Shapiro N, Whitman WB, Venter SN, Steenkamp ET. Genome-informed Bradyrhizobium taxonomy: where to from here? Syst Appl Microbiol 2019; 42:427-439. [PMID: 31031014 DOI: 10.1016/j.syapm.2019.03.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/26/2019] [Accepted: 03/26/2019] [Indexed: 02/06/2023]
Abstract
Bradyrhizobium is thought to be the largest and most diverse rhizobial genus, but this is not reflected in the number of described species. Although it was one of the first rhizobial genera recognised, its taxonomy remains complex. Various contemporary studies are showing that genome sequence information may simplify taxonomic decisions. Therefore, the growing availability of genomes for Bradyrhizobium will likely aid in the delineation and characterization of new species. In this study, we addressed two aims: first, we reviewed the availability and quality of available genomic resources for Bradyrhizobium. This was achieved by comparing genome sequences in terms of sequencing technologies used and estimated level of completeness for inclusion in genome-based phylogenetic analyses. Secondly, we utilized these genomes to investigate the taxonomic standing of Bradyrhizobium in light of its diverse lifestyles. Although genome sequences differed in terms of their quality and completeness, our data indicate that the use of these genome sequences is adequate for taxonomic purposes. By using these resources, we inferred a fully resolved, well-supported phylogeny. It separated Bradyrhizobium into seven lineages, three of which corresponded to the so-called supergroups known for the genus. Wide distribution of key lifestyle traits such as nodulation, nitrogen fixation and photosynthesis revealed that these traits have complicated evolutionary histories. We present the first robust Bradyrhizobium species phylogeny based on genome sequence information for investigating the evolution of this important assemblage of bacteria. Furthermore, this study provides the basis for using genome sequence information as a resource to make important taxonomic decisions, particularly at the species and genus levels.
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Affiliation(s)
- Juanita R Avontuur
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Chrizelle W Beukes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Wai Y Chan
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa; Biotechnology Platform, Agricultural Research Council Onderstepoort Veterinary Institute (ARC-OVI), Onderstepoort 0110, South Africa
| | - Martin P A Coetzee
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Tomasz Stępkowski
- Autonomous Department of Microbial Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences (SGGW), Poland
| | | | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, United States
| | - Nicole Shapiro
- DOE Joint Genome Institute, Walnut Creek, CA, United States
| | - William B Whitman
- Department of Microbiology, University of Georgia, Athens, GA, United States
| | - Stephanus N Venter
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa. http://emma.steenkamp.up.ac.za
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