Bradyrhizobium spp. (TGx) isolates nodulating the new soybean cultivars in Africa are diverse and distinct from bradyrhizobia that nodulate North American soybeans.

Abaidoo, Robert C.; Keyser, H. H.; Singleton, Paul; Borthakur, Dulal

doi:10.1099/00207713-50-1-225

Cited by 48 publications

(38 citation statements)

References 17 publications

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“…In conclusion, despite the low variability reported for the 16S rRNA region of Bradyrhizobium in some studies (So et al, 1994;Urtz & Elkan, 1996;Moreira et al, 1998;Molouba et al, 1999;van Berkum & Fuhrmann, 2000;Chen et al, 2000;Willems et al, 2001), and despite the coefficients used in some of the analyses being different, the strains from our study were joined at a very low level of similarity, 28 %, showing greater variability than any previous report. For example, an analysis of African indigenous soybean bradyrhizobia by RFLP-PCR with five restriction enzymes grouped the strains with a similarity of 70 % (Abaidoo et al, 2000), while in strains from native leguminous species of Senegal, the similarity with five restriction enzymes was approximately 74 %, decreasing to 55 % when a strain from Aeschynomene was included (Doignon-Bourcier et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Sequencing analysis of ribosomal genes of several strains can be very expensive; however, PCR-based locus-specific RFLP associated with ribosomal genes may be convenient for phylogenetic studies, generally showing high reproducibility and good agreement with partial or complete gene sequencing (Laguerre et al, 1994(Laguerre et al, , 1996Vinuesa et al, 1998;Wang et al, 1999;Abaidoo et al, 2000;Jarabo-Lorenzo et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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RFLP analysis of the rRNA operon of a Brazilian collection of bradyrhizobial strains from 33 legume species

Germano

Menna

Mostasso

et al. 2006

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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Genetic diversity in tropical rhizobial species is still poorly known. With the aim of increasing this knowledge, three ribosomal regions of 119 strains belonging to the official Brazilian culture collection of rhizobia and classified as Bradyrhizobium based on morphological and physiological characteristics in vitro were analysed by RFLP-PCR. The strains were isolated from 33 legume species, representing nine tribes and all three subfamilies; they all form very effective N 2 -fixing nodules and 43 of them are recommended for use in Brazilian commercial inoculants as the most effective for their hosts. For the 16S rRNA gene, type and reference strains of Bradyrhizobium japonicum fell into two major clusters, joined at a level of similarity of 50 %, which included 52 strains, 90 % of which were isolated from soybean. Two other clusters, joined at a similarity of 53 %, included reference strains of Bradyrhizobium elkanii, but not USDA 76 T ; furthermore, two other major clusters were identified and all strains were clustered at a final level of similarity of only 28 %. For the intergenic spacer (IGS) between genes coding for the 16S and 23S rRNA, strains were clustered at a final level of similarity of 27 %. Reference strains of B. japonicum fell into a major group with 51 strains, 84 % isolated from soybean, with a similarity of 59 %, while strains of B. elkanii fell into another major group, with a similarity of 55 %, clustering 44 strains, 59 % of which were isolated from hosts other than soybean. New clusters were also observed for the IGS region. The largest number of differences was detected in the analysis of the 23S rRNA gene, and 16 groups and isolated strains were joined at a very low level of similarity (16 %). In a combined analysis with the three ribosomal regions, the majority of strains isolated from soybean clustered with a similarity of 54 % with type and reference strains of B. japonicum, while most strains isolated from Brazilian indigenous legume species grouped with B. elkanii at a level of similarity of 46 %. All strains were clustered at a very low level of similarity (27 %), and at least two new clusters were clearly defined. These new clusters might be related to intraspecific differences or to novel subspecies, or even to novel species; indeed, strains from one of these clusters show higher 16S rRNA gene sequence similarity to members of the genus Burkholderia. The results obtained in this study emphasize the high level of diversity of symbiotic diazotrophic bacteria in the tropics that still remains to be determined. INTRODUCTIONThe Leguminosae (known as the Fabaceae in the USA) is one of the largest families of plants, with over 18 000 species classified into around 650 genera, representing approximately one-twelfth of all known flowering plants and occupying nearly all terrestrial biomes (Polhill & Raven, 1981). Many species within this family are capable of establishing symbioses with a group of bacteria collectively called rhizobia, of which the most important feature is the capacity...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

RFLP analysis of the rRNA operon of a Brazilian collection of bradyrhizobial strains from 33 legume species

Germano

Menna

Mostasso

et al. 2006

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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“…which form symbiotic nodules with cowpea (IITA, 1996). Relatedly, Abaidoo et al (2000) detected Bradyrhizobium spp. populations in approximately 74% of the African soils.…”

Section: Introductionmentioning

confidence: 99%

Screening soybean genotypes for promiscuous symbiotic association with <i>Bradyrhizobium</i> strains

Agoyi¹,

Afutu²,

Tumuhairwe³

et al. 2016

Afr. Crop Sci. J.

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“…that belong to the cowpea "crossinoculation" group [14,15]. Abaidoo et al [16] detected Bradyrhizobium spp. populations in approximately 74% of the African soils; hence, promiscuous soybean cultivars would yield well without seed inoculation and ameliorate soils for subsequent crops in Africa.…”

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confidence: 99%

Genotype by environment effects on promiscuous nodulation in soybean (Glycine max L. Merrill)

et al. 2017

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Background: Understanding factors influencing the expression of a trait is key in designing a breeding program. Genotype by environment interaction has great influence on most quantitative traits. Promiscuous nodulation is a trait of importance for soybean production in Africa, because of the soil bacteria Bradyrhizobium japonicum not being indigenous in most African soils. Most soybean cultivars require B. japonicum for nodulation leading to the need for seed inoculation before sowing soybean in Africa. Few cultivars have capability to nodulate with Bradyrhizobia spp. that are different from B. japonicum and native in African soils. Such cultivars are termed "promiscuous cultivars. " Field experiments were conducted in six locations in Uganda for two seasons, to investigate the extent of environmental influences on the nodulation ability of promiscuous soybean genotypes. Results:Additive main effect and multiplicative interaction effects showed highly significant environment and genotype by environment (G × E) interaction effects on all nodulation traits. G × E interaction contributed more to the total variation than genotypes. The genotypes Kabanyolo I and WonderSoya were the most stable for nodules' dry weight (NDW), which is the nodulation trait the most correlated with grain yield. Genotype UG5 was the most stable for nodules' number (NN), and Nam II for nodules' effectiveness (NE). The genotype NamSoy 4M had the highest performance for NN, NFW, and NDW, but was less stable. WonderSoya had the highest NE. Genotype and genotype by environment analysis grouped environments into mega-environments (MEs), and four MEs were observed for NDW, with NamSoy 4M the winning genotype in the largest ME, and Kasese B the ideal environment for that nodulation trait. Conclusion:This study provides information that can guide breeding strategies. The low genetic effect that led to high environmental and G × E interaction effects raised the need for multi-environments testing before cultivar selection and recommendation. The study revealed genotypes that are stable and others that are high performing for nodulation traits, and which can be used as parental lines in breeding programs.

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Bradyrhizobium spp. (TGx) isolates nodulating the new soybean cultivars in Africa are diverse and distinct from bradyrhizobia that nodulate North American soybeans.

Cited by 48 publications

References 17 publications

RFLP analysis of the rRNA operon of a Brazilian collection of bradyrhizobial strains from 33 legume species

RFLP analysis of the rRNA operon of a Brazilian collection of bradyrhizobial strains from 33 legume species

Screening soybean genotypes for promiscuous symbiotic association with <i>Bradyrhizobium</i> strains

Genotype by environment effects on promiscuous nodulation in soybean (Glycine max L. Merrill)

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