Multilocus sequence analyses reveal several unnamed Mesorhizobium genospecies nodulating Acacia species and Sesbania sesban trees in Southern regions of Ethiopia

Degefu, Tulu; Wolde-meskel, Endalkachew; Frostegård, Åsa

doi:10.1016/j.syapm.2010.09.006

Cited by 44 publications

(37 citation statements)

References 55 publications

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“…The results (Fig. S1) were in agreement with the single-gene phylogenies generated in the present study, and also with those in the previous study (Degefu et al, 2011). The phylogenetic analysis of concatenated gene sequences grouped the test strains into three well-supported (100 % bootstrap value) monophyletic clades, with M. plurifarium and M. silamurunense more distantly related (Fig.…”

supporting

confidence: 92%

“…1), showed that the strains formed three well-supported clusters corresponding to the three unique genospecies previously defined (Degefu et al, 2011). The novel isolates within each of the designated genospecies shared sequence similarity ranging between 99 % and 100 % with each other for the sequences of the atpD and glnII genes.…”

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confidence: 85%

“…Based on the 16S rRNA phylogeny this genus forms a well-defined clade different from the Rhizobium-Ensifer-Agrobacterium clusters (Jarvis et al, 1997 In the course of studies of a large number of rhizobial isolates nodulating agroforestry legume species growing in southern Ethiopia, 18 strains nodulating Sesbania sesban and three Acacia species, were found to belong to the Mesorhizobium branch, with distinctive amplified fragment length polymorphism (AFLP) and 16S rRNA-RFLP patterns (Wolde-meskel et al, 2004;Wolde-meskel et al, 2005). The taxonomic diversity of these isolates was further revealed by MLSA of selected housekeeping genes and they were shown to have distinct individual core gene types, thus occupying three distinct positions in the phylogenetic tree (Degefu et al, 2011). In the present study we further extended the characterization of the strains representing the three unique genomic species, following a polyphasic taxonomic approach (analyses of DNA-DNA relatedness, major fatty acids profiles and morphological/phenotypic features), as this is currently suggested for descriptions of new species (Stackebrandt et al, 2002).…”

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confidence: 99%

“…We designed and conducted the hybridization experiments based on the results from our previous MLSA (Degefu et al, 2011). Highmolecular-mass DNA for DNA-DNA hybridization studies and DNA base composition determination was extracted using the method of Wilson (1987), with minor modifications (Cleenwerck et al, 2002).…”

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confidence: 99%

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Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov., isolated from root nodules of different agroforestry legume trees

Degefu

Wolde-meskel

Liu

et al. 2013

International Journal of Systematic and Evolutionary Microbiology

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A total of 18 strains, representing members of the genus Mesorhizobium , obtained from root nodules of woody legumes growing in Ethiopia, have been previously shown, by multilocus sequence analysis (MLSA) of five housekeeping genes, to form three novel genospecies. In the present study, the phylogenetic relationship between representative strains of these three genospecies and the type strains of their closest phylogenetic neighbours Mesorhizobium plurifarium , Mesorhizobium amorphae , Mesorhizobium septentrionale and Mesorhizobium huakuii was further evaluated using a polyphasic taxonomic approach. In line with our earlier MLSA of other housekeeping genes, the phylogenetic trees derived from the atpD and glnII genes grouped the test strains into three well-supported, distinct lineages that exclude all defined species of the genus Mesorhizobium . The DNA–DNA relatedness between the representative strains of genospecies I–III and the type strains of their closest phylogenetic neighbours was low (≤59 %). They differed from each other and from their closest phylogenetic neighbours by the presence/absence of several fatty acids, or by large differences in the relative amounts of particular fatty acids. While showing distinctive features, they were generally able to utilize a wide range of substrates as sole carbon and nitrogen sources. The strains belonging to genospecies I, II and III therefore represent novel species for which we propose the names Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov. The isolates AC39aT ( = LMG 26966T = HAMBI 3295T), AC99bT ( = LMG 26968T = HAMBI 3301T) and AC98cT ( = LMG 26967T = HAMBI 3306T) are proposed as type strains for the respective novel species.

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confidence: 92%

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confidence: 85%

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confidence: 99%

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confidence: 99%

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Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov., isolated from root nodules of different agroforestry legume trees

Degefu

Wolde-meskel

Liu

et al. 2013

International Journal of Systematic and Evolutionary Microbiology

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“…Farmers usually retain between 1-20 trees of selected species per hectare and minimize impact on the companion crops through occasional lopping and pollarding of trees (Poschen 1986). Examples of this practice include Cordia africana intercropping with maize in sub-humid zones (Yadessa et al 2009), Faidherbia-based agroforestry in teff-wheat zones (Poschen 1986) and a diverse range of Acacia species such as A. tortilis and A. senegal in fields in low lying savanna regions (Degefu et al 2011). It is also common for farmers to deliberately plant and manage trees on their farms, such as fast growing timber woodlots predominantly using Eucalyptus spp.…”

Section: Abstract Characterization á Farmer Managed Natural Regeneratmentioning

confidence: 99%

Understanding patterns of tree adoption on farms in semi-arid and sub-humid Ethiopia

et al. 2016

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Trees on farms are a widespread feature of landscapes across a large part of Ethiopia with an important role in enhancing the resilience of smallholder livelihoods through the provision of ecosystem services. Despite their importance, little is known about what trees are planted or retained from natural regeneration by different types of farmers that results in the pattern of tree cover found in the region. We address this knowledge gap through analysis of household survey data from semi-arid and sub humid areas of Oromia regional state. A set of composite variables that represent distinctive patterns of tree cover on farms were derived from principal component analysis and Pearson correlation analysis. This revealed two major tree adoption strategies: farmer managed natural regeneration (FMNR) of trees to meet subsistence needs as well as contributing to other ecosystem services; and, high value agroforestry (HVAF) involving planted trees used largely to produce fruits, timber and fodder. Regression analysis further identified fine-scale variation in ecological and socio-economic factors that affect which of these two broad strategies are adopted by farmers. Favorable climatic conditions coupled with institutional arrangements to control free grazing were pre-conditions for HVAF, whereas poor biophysical potential and sloping land provided a positive incentive for farmers to adopt FMNR. Farmers with preferences for tree species with multiple utilities and locational flexibility favored FMNR while adoption of HVAF was more assetdriven. Our findings reveal that farmers integrate many native and exotic tree species on their farms to meet their variable farm conditions, needs and asset profiles in stark contrast to most tree promotion efforts that focus on a few, usually exotic, tree species. We recommend that future agroforestry promotion should embrace a diversity of tree species appropriate to matching the fine scale variation in ecological conditions and farmer circumstances encountered in the field.

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Current Status of the Taxonomy of Bacteria Able to Establish Nitrogen-Fixing Legume Symbiosis

Velázquez

García‐Fraile

Ramírez-Bahena

et al. 2017

Microbes for Legume Improvement

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Multilocus sequence analyses reveal several unnamed Mesorhizobium genospecies nodulating Acacia species and Sesbania sesban trees in Southern regions of Ethiopia

Cited by 44 publications

References 55 publications

Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov., isolated from root nodules of different agroforestry legume trees

Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov., isolated from root nodules of different agroforestry legume trees

Understanding patterns of tree adoption on farms in semi-arid and sub-humid Ethiopia

Current Status of the Taxonomy of Bacteria Able to Establish Nitrogen-Fixing Legume Symbiosis

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