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Competitiveness and Phylogenetic Relationship of Rhizobial Strains with Different Symbiotic Efficiency in Trifolium repens: Conversion of Parasitic into Non-Parasitic Rhizobia by Natural Symbiotic Gene Transfer. BIOLOGY 2023; 12:biology12020243. [PMID: 36829520 PMCID: PMC9953144 DOI: 10.3390/biology12020243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/09/2023]
Abstract
In Uruguayan soils, populations of native and naturalized rhizobia nodulate white clover. These populations include efficient rhizobia but also parasitic strains, which compete for nodule occupancy and hinder optimal nitrogen fixation by the grassland. Nodulation competitiveness assays using gusA-tagged strains proved a high nodule occupancy by the inoculant strain U204, but this was lower than the strains with intermediate efficiencies, U268 and U1116. Clover biomass production only decreased when the parasitic strain UP3 was in a 99:1 ratio with U204, but not when UP3 was at equal or lower numbers than U204. Based on phylogenetic analyses, strains with different efficiencies did not cluster together, and U1116 grouped with the parasitic strains. Our results suggest symbiotic gene transfer from an effective strain to U1116, thereby improving its symbiotic efficiency. Genome sequencing of U268 and U204 strains allowed us to assign them to species Rhizobium redzepovicii, the first report of this species nodulating clover, and Rhizobium leguminosarun, respectively. We also report the presence of hrrP- and sapA-like genes in the genomes of WSM597, U204, and U268 strains, which are related to symbiotic efficiency in rhizobia. Interestingly, we report here chromosomally located hrrP-like genes.
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Yan Z, Sang L, Ma Y, He Y, Sun J, Ma L, Li S, Miao F, Zhang Z, Huang J, Wang Z, Yang G. A de novo assembled high-quality chromosome-scale Trifolium pratense genome and fine-scale phylogenetic analysis. BMC PLANT BIOLOGY 2022; 22:332. [PMID: 35820796 PMCID: PMC9277957 DOI: 10.1186/s12870-022-03707-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/20/2022] [Indexed: 05/12/2023]
Abstract
BACKGROUND Red clover (Trifolium pratense L.) is a diploid perennial temperate legume with 14 chromosomes (2n = 14) native to Europe and West Asia, with high nutritional and economic value. It is a very important forage grass and is widely grown in marine climates, such as the United States and Sweden. Genetic research and molecular breeding are limited by the lack of high-quality reference genomes. In this study, we used Illumina, PacBio HiFi, and Hi-C to obtain a high-quality chromosome-scale red clover genome and used genome annotation results to analyze evolutionary relationships among related species. RESULTS The red clover genome obtained by PacBio HiFi assembly sequencing was 423 M. The assembly quality was the highest among legume genome assemblies published to date. The contig N50 was 13 Mb, scaffold N50 was 55 Mb, and BUSCO completeness was 97.9%, accounting for 92.8% of the predicted genome. Genome annotation revealed 44,588 gene models with high confidence and 52.81% repetitive elements in red clover genome. Based on a comparison of genome annotation results, red clover was closely related to Trifolium medium and distantly related to Glycine max, Vigna radiata, Medicago truncatula, and Cicer arietinum among legumes. Analyses of gene family expansions and contractions and forward gene selection revealed gene families and genes related to environmental stress resistance and energy metabolism. CONCLUSIONS We report a high-quality de novo genome assembly for the red clover at the chromosome level, with a substantial improvement in assembly quality over those of previously published red clover genomes. These annotated gene models can provide an important resource for molecular genetic breeding and legume evolution studies. Furthermore, we analyzed the evolutionary relationships among red clover and closely related species, providing a basis for evolutionary studies of clover leaf and legumes, genomics analyses of forage grass, the improvement of agronomic traits.
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Affiliation(s)
- Zhenfei Yan
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Lijun Sang
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Yue Ma
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Yong He
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Juan Sun
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Lichao Ma
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Shuo Li
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Fuhong Miao
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China
| | - Zixin Zhang
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China
| | | | - Zengyu Wang
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China.
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China.
| | - Guofeng Yang
- College of Grassland Science, Qingdao Agricultural University, Qingdao, 266109, China.
- Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, Qingdao, 266109, China.
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Irisarri P, Cardozo G, Tartaglia C, Reyno R, Gutiérrez P, Lattanzi FA, Rebuffo M, Monza J. Selection of Competitive and Efficient Rhizobia Strains for White Clover. Front Microbiol 2019; 10:768. [PMID: 31065250 PMCID: PMC6489563 DOI: 10.3389/fmicb.2019.00768] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 03/26/2019] [Indexed: 11/16/2022] Open
Abstract
The practice of inoculating forage legumes with rhizobia strains is widespread. It is assumed that the inoculated strain determines the performance of the symbiosis and nitrogen fixation rates. However, native-naturalized strains can be competitive, and actual nodule occupancy is often scarcely investigated. In consequence, failures in establishment, and low productivity attributed to poor performance of the inoculant may merely reflect the absence of the inoculated strain in the nodules. This study lays out a strategy followed for selecting a Rhizobium leguminosarum sv. trifolii strain for white clover (Trifolium repens) with competitive nodule occupancy. First, the competitiveness of native-naturalized rhizobia strains selected for their efficiency to fix N2 in clover and tagged with gusA was evaluated in controlled conditions with different soils. Second, three of these experimental strains with superior nodule occupancy plus the currently recommended commercial inoculant, an introduced strain, were tested in the field in 2 years and at two sites. Plant establishment, herbage productivity, fixation of atmospheric N2 (15N natural abundance), and nodule occupancy (ERIC-PCR genomic fingerprinting) were measured. In both years and sites, nodule occupancy of the native-naturalized experimental strains was either higher or similar to that of the commercial inoculant in both primary and secondary roots. The difference was even greater in stolon roots nodules, where nodule occupancy of the native-naturalized experimental strains was at least five times greater. The amount of N fixed per unit plant mass was consistently higher with native-naturalized experimental strains, although the proportion of N derived from atmospheric fixation was similar for all strains. Plant establishment and herbage production, as well as clover contribution in oversown native grasslands, were either similar or higher in white clover inoculated with the native-naturalized experimental strains. These results support the use of our implemented strategy for developing a competitive inoculant from native-naturalized strains.
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Affiliation(s)
- Pilar Irisarri
- Laboratorio de Microbiología, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Gerónimo Cardozo
- Instituto Nacional de Investigación Agropecuaria, INIA Treinta y Tres, Treinta y Tres, Uruguay
| | - Carolina Tartaglia
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Rafael Reyno
- Instituto Nacional de Investigación Agropecuaria, INIA Tacuarembó, Tacuarembó, Uruguay
| | - Pamela Gutiérrez
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Fernando A. Lattanzi
- Instituto Nacional de Investigación Agropecuaria, INIA La Estanzuela, Colonia, Uruguay
| | - Mónica Rebuffo
- Instituto Nacional de Investigación Agropecuaria, INIA La Estanzuela, Colonia, Uruguay
| | - Jorge Monza
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
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Diversity and symbiotic effectiveness of indigenous rhizobia-nodulating Adesmia bicolor in soils of Central Argentina. Curr Microbiol 2012; 66:174-84. [PMID: 23099430 DOI: 10.1007/s00284-012-0260-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
Native perennial legume Adesmia bicolor reveals characteristics that are key to securing persistence under grazing. Literature on the diversity and symbiotic effectiveness of indigenous rhizobia-nodulating A. bicolor in central Argentina is limited. The purpose of this study was therefore to determine phenotypic and genotypic variability as well as biological N-fixation effectiveness in rhizobia isolated from A. bicolor nodules. To this end, repetitive genomic regions were analyzed using ERIC primers. In the greenhouse, plants were grown under a (i) N-fertilized treatment, (ii) N-free control treatment, and (iii) rhizobia inoculation treatment. Dry weight and N-content were analyzed. All isolates belonged to Rhizobium genus and showed high symbiotic effectiveness. The N-content/subterranean N-content ratio in aerial and subterranean parts of inoculated plants was higher than that observed in N-fertilized plants during the vegetative stage. Results from this study demonstrate that symbiosis between native rhizobial strains and A. bicolor is very effective.
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Wadhwa K, Dudeja SS, Yadav RK. Molecular diversity of native rhizobia trapped by five field pea genotypes in Indian soils. J Basic Microbiol 2011; 51:89-97. [PMID: 20806252 DOI: 10.1002/jobm.201000065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 04/07/2010] [Indexed: 11/09/2022]
Abstract
Five pea cultivars; HFP 4, HVP 3-5, HFP 9426, Jayanti and Hariyal, being grown in CCS Haryana Agricultural University farm were used to isolate native rhizobia. Selected 54 rhizobia, from all cultivars, were authenticated as rhizobia by plant infectivity test. Along with nodulation, symbiotic effectiveness in terms of symbiotic ratios showed wide range of effectiveness of pea rhizobia from 1.11 to 5.0. DNA of all the 54 rhizobia was extracted and amplified by PCR, using ERIC and 16S rDNA primers. Dendrogram based on ERIC profiles of these 54 rhizobia showed the formation of 13 subclusters at 80% level of similarity. Dendrogram based on RFLP of 16S rDNA by three restriction endonucleases; Msp I, Csp 6I and Rsa I; also formed 13 subclusters at 80% level of similarity. However, positioning of subclusters was different from that of ERIC based dendrogram. Majority of the isolates i.e. 64.8% by ERIC profiles and 44.4% by RFLP of 16S rDNA formed one cluster. Isolates from same nodule were not 100% similar. Considering each cluster representing a rhizobial genotype, both techniques used to assess molecular diversity indicated the presence of 13 genotypes of field pea rhizobia in CCS Haryana Agricultural University farm soil. Two pea rhizobial genotypes were able to nodulate all the five pea cultivars. Furthermore, high strain richness index (0.43-0.5) of field pea rhizobia was observed by both the techniques.
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Affiliation(s)
- K Wadhwa
- Department of Microbiology, CCS Haryana Agricultural University, Hisar, India
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Ramírez-Bahena MH, Velázquez E, Fernández-Santos F, Peix A, Martínez-Molina E, Mateos PF. Phenotypic, genotypic, and symbiotic diversities in strains nodulating clover in different soils in Spain. Can J Microbiol 2009; 55:1207-16. [PMID: 19935893 DOI: 10.1139/w09-074] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Trifolium species are the most common legumes present in wild Spanish soils; however, there are no studies to date on the diversity of rhizobia nodulating clover in Spain. Twenty strains from different Spanish soils with acidic, neutral, and basic pH were selected to study their genotypic, phenotypic, and symbiotic features. The results showed that the isolates were genotypically diverse, displaying 12 different DNA fingerprint patterns and also 14 different plasmid profiles. Although they have 16S rRNA gene sequences that are nearly identical to that of the type strain of Rhizobium leguminosarum, their recA and atpD gene sequences were phylogenetically divergent from those of R. leguminosarum reference strains, and phenotypic divergence as well as different host ranges were also found. Although most of them nodulated both Trifolium and Phaseolus, only 5 strains were also able to nodulate Pisum. The results of the effectiveness analysis showed a high variability in the symbiotic characteristics of our strains and suggested that Pisum is the more restrictive host of this group. Interestingly, some of the Trifolium isolates showed an ability to promote growth of Pisum in the absence of nodulation.
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