Minimal Antigenic Constitution of 28 Strains of Rhizobium Japonicum

Date, R. A.; Decker, Annegrit

doi:10.1139/m65-001

Cited by 64 publications

(49 citation statements)

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“…Also, the consideration of serogroup 135 as a species distinct from B. japonicum while maintaining serogroup 110 as a species of B. japonicum would be inconsistent. Serogroups 110 and 6 are distinguishable by DNA homology (Hollis et al, 1981), by fatty acid methyl ester analyses (Graham et al, 1995), by serology (Date & Decker, 1965) and, as we report, by 16S rRNA gene and ITS region sequences.It has become customary to define species limits among the rhizobia by low DNA homology values and this criterion was used as the predominant evidence in support for the proposal of B. liaoningense as a species distinct from B. japonicum and B. elkanii (Xu et al, 1995). Although DNA homology has become widely used to define species limits in rhizobia, it is important to consider that this practice has received criticism based upon interpretation of results.…”

supporting

confidence: 70%

Evolutionary relationships among the soybean bradyrhizobia reconstructed from 16S rRNA gene and internally transcribed spacer region sequence divergence.

Berkum¹,

Fuhrmann²

2000

International Journal of Systematic and Evolutionary Microbiology

168

124

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From sequence divergence of 16S rRNA genes and the internally transcribed spacer (ITS) region it is reported that variation in phylogenetic placement exists among the 17 different serotype strains of Bradyrhizobium that have been isolated from nodules of soybean. Evolutionary relationships among the bradyrhizobia were more resolved using reconstructions derived from ITS than from 16S rRNA gene sequence divergence. Strain USDA 129 was placed together with USDA 62, 110, 122 and 126, but did not cluster with USDA 123 and 127, with which it shares antigenic determinants. The results from the phylogenetic analysis were supported with data from determinations of genetic diversity among additional strains within each of these serogroups using amplified fragment length polymorphism analysis. From these results it was concluded that strains of serogroup 129 were more similar to strains of serogroups 62, 110 and 122 than they were to strains of serogroups 123 and 127. The serotype strain of Bradyrhizobium japonicum USDA 135 and the type strain for Bradyrhizobium liaoningense possessed identical 16S rRNA gene and ITS region sequences. Also, the type strain for B. liaoningense cross-reacted with antisera prepared against somatic antigens of USDA 135. Therefore, it was not possible to distinguish B. liaoningense from serogroup 135 in our analysis of B. japonicum and Bradyrhizobium elkanii.Keywords : Bradyrhizobium, phylogeny, soybean, Glycine max, serology INTRODUCTIONTraditional classification schemes of living organisms rely upon variation in morphological characters and a fossil record. Since there are only few useful morphological characters for rhizobia, classification schemes based on variation in genetic characters are often more informative than schemes based on phenotypic variation. An advantage of this approach is that DNA sequences and gene products can be compared The GenBank accession numbers for the ITS region sequences of strains USDA 122, 123, 124, 125, 126, 127, 129, 130, 135, 31, 3622 T (Bradyrhizobium liaoningense), 38, 4, 46, 62 and 94 are AF208503-AF208518, respectively. The GenBank accession numbers U35000 and U69638 were modified to reflect the sequencing results obtained with strains USDA 76 T and 6 T , respectively.in an evolutionary context (molecular systematics). Usually evolutionary history (or phylogeny) is then represented as a bifurcating hierarchical tree. It has become acceptable to reconstruct such evolutionary relationships among bacteria from data of sequence divergence among their 16S rRNA genes (Maidak et al., 1994).Published investigations of evolutionary relationships and genetic diversity in rhizobia has been focused more on the genera Rhizobium, Sinorhizobium and Mesorhizobium rather than Bradyrhizobium. Most reported data of diversity in Bradyrhizobium are centred on the symbionts of soybean. Initially, Bradyrhizobium (Rhizobium) japonicum was the only recognized species (Fred et al., 1932 ; Jordan, 1982). Later, Hollis et al. (1981) separated B. japonicum into three DNA homolog...

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supporting

confidence: 70%

Evolutionary relationships among the soybean bradyrhizobia reconstructed from 16S rRNA gene and internally transcribed spacer region sequence divergence.

Berkum¹,

Fuhrmann²

2000

International Journal of Systematic and Evolutionary Microbiology

168

124

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“…Most of the strains that belong to these species were isolated or associated with nodules on Glycine spp. In addition to the species subdivision, a number of serogroups have been described among slow-growing soybean symbionts (Date & Decker, 1965). Many other slow-growing rhizobia have been isolated from other legume hosts such as Arachis hypogaea (Urtz & Elkan, 1996 ;Zhang et al, 1999), Lupinus (Barrera et al, 1997), Aeschynomene (Molouba et al, 1999) and others (Laguerre et al, 1997 ;Lafay & Burdon, 1998 ;Vinuesa et al, 1998 ;Sterner & Parker, 1999 ;Doignon-Bourcier et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

DNA-DNA hybridization study of Bradyrhizobium strains.

Willems

Doignon-Bourcier²,

Goris³

et al. 2001

International Journal of Systematic and Evolutionary Microbiology

200

127

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DNA-DNA hybridizations were performed between Bradyrhizobium strains, isolated mainly from Faidherbia albida and Aeschynomene species, as well as Bradyrhizobium reference strains. Results indicated that the genus Bradyrhizobium consists of at least 11 genospecies, I to XI. The genospecies formed four subgeneric groups that were more closely related to each other (S 40 % DNA hybridization) than to other genospecies (T 40 % DNA hybridization) : (i) genospecies I (Bradyrhizobium japonicum), III (Bradyrhizobium liaoningense), IV and V ; (ii) genospecies VI and VIII ; (iii) genospecies VII and IX ; and (iv) genospecies II (Bradyrhizobium elkanii), X and XI. Photosynthetic Aeschynomene isolates were found to belong to at least two distinct genospecies in one subgeneric group. DNA-DNA hybridization data are compared with data from amplified fragment length polymorphism analysis and 16S-23S rDNA spacer sequence analysis.

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“…1,2) Throughout the years, scientists around the world have isolated a great number of bradyrhizobial strains from different climatic and geographical regions from a broad spectrum of host plants, such as Glycine max, 3) Parasponia, 4) Arachis hypogaea, 5) Lupinus, 6) Aeschynomene, 7) Beta vulgaris, 8) Adenocarpus, Chamaecytisus, Spartocytisus, 9) and Desmodium. 10) Diversity studies have been conducted to gain a better understanding of the taxonomy and distribution of bradyrhizobia, and to screen for strains that might be of use in agriculture and environmental management.…”

mentioning

confidence: 99%