Role of hsfA gene on host-specificity by Bradyrhizobium japonicum in a broad range of tropical legumes

1999 ◽  
Vol 46 (1) ◽  
pp. 81-84
Author(s):  
Hye-Sook Oh ◽  
Jong-Yoon Chun ◽  
Myung-Sok Lee ◽  
Kyung-Hee Min ◽  
Suk-Ha Lee ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Host Specificity ◽  
Bradyrhizobium Japonicum ◽  
Deletion Mutant ◽  
Insertion Mutant ◽  
Legume Species ◽  
Vigna Angularis ◽  
Tropical Legumes

Bradyrhizobium japonicum mutant strain NAD163, containing a 30-kb deletion mutant encompassing the hsfA gene, was inoculated onto a broad range of legume species to test host-specificity. Most legume species formed ineffective nodules except Vigna angularis var. Chibopat and Glycine max var. Pureunkong. A hsfA insertion mutant, BjjC211, gave similar results to strain NAD163, implying that many legume species require HsfA for host-specific nitrogen fixation. To determine whether other genes in the deleted region of NAD163 are also necessary, the hsfA gene was conjugally transferred into the NAD163 mutant. The transconjugant formed effective nodules on the host legume plants, which earlier had formed ineffective nodules with mutant NAD163. Thus, we conclude that the hsfA gene in the 30-kb region is the only factor responsible for host-specific nitrogen fixation in legume plants.Key words: host-specific nitrogen fixation, legume-Rhizobium symbiosis, hsfA gene, host-specificity.

Role of hsfA gene on host-specificity by Bradyrhizobium japonicum in a broad range of tropical legumes

2000 ◽  
Vol 46 (1) ◽  
pp. 81-84 ◽  
Author(s):  
Hye-Sook Oh ◽  
Jong-Yoon Chun ◽  
Myung-Sok Lee ◽  
Kyung-Hee Min ◽  
Suk-Ha Lee ◽  
...  
Keyword(s):  
Host Specificity ◽  
Bradyrhizobium Japonicum ◽  
Tropical Legumes ◽  
I Gene

Nodulation efficiency of Bradyrhizobium japonicum strains with genotypes of soybean varying in the ability to restrict nodulation

1994 ◽  
Vol 40 (6) ◽  
pp. 456-460 ◽  
Author(s):  
M. L. Ferrey ◽  
P. H. Graham ◽  
M. P. Russelle
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Lateral Root ◽  
Root Tip ◽  
Similar Concentration ◽  
Root Nodulation ◽  
American Midwest ◽  
Japonicum Strain ◽  
Average Position

Competition from existing soil rhizobia has limited the benefits from nitrogen fixation for soybean grown in the American Midwest. A strategy being considered to overcome this problem is the use of varieties that are restricted in nodulation with soil strains, but nodulate normally with inoculant bradyrhizobia. In this study we examine the efficiency in nodulation of strains of Bradyrhizobium japonicum that have been reported as restricted in nodulation with specific genotypes of soybean, using a root-tip marking procedure in growth pouches. When B. japonicum USDA110 was applied to the soybean cultivars Hardee and Fiskeby V at the rate of 3.50 × 104 cells/pouch, more than 75% of the plants were nodulated above the root-tip mark, and average uppermost nodule position was above the root-tip mark. By contrast, when this strain was applied in similar concentration to the soybean cultivar Peking, few plants developed nodules above the root-tip mark, and the average position of the uppermost taproot nodule was nearly 30 mm below this mark. Nodulation was improved at higher rates of inoculation, but even when 3.50 × 106 cells were applied to each pouch, less than 50% of the plants were nodulated above the root-tip mark. Bradyrhizobium japonicum strain CB1809 (=USDA136) was also efficient in nodulation with cv. Fiskeby V, but with cv. Hardee, less than 65% of plants were nodulated above the root-tip mark, irrespective of inoculation rate. Because restriction of nodulation with the strains initially tested was not absolute, we examined the patterns of nodulation obtained following the inoculation of two restriction hosts, Peking and PI371607. In pure culture, serogroup USDA110 strains failed to induce significant taproot nodulation of cv. Peking in Leonard jars, but did induce lateral root nodulation. However, in a glasshouse experiment contrasting soil- and seed-applied inoculant, lateral-root nodulation of the restriction host PI371607 by USDA123 was not significant.Key words: Glycine max, competition, restriction, nodulation.

scholarly journals Biological nitrogen fixation and agronomic features of soybean (Glycine max (L.) Merr.) crop under different doses of inoculant

2018 ◽  
Vol 67 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Alessandro Pedrozo ◽  
Nelson João Girelli de Oliveira ◽  
Odair Alberton
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Biological Nitrogen Fixation ◽  
Bradyrhizobium Japonicum ◽  
Glycine Max L ◽  
Agronomic Features ◽  
Biological Nitrogen ◽  
Different Doses

La soya es uno de los cultivos más importantes del mundo y presenta una gran versatilidad. Este estudio tiene como objetivo investigar el efecto del inoculante Bradyrhizobium japonicum a 0, 600 y 1200 ml ha-1 en cultivo de soya, con y sin 1 L ha-1 calcio (Ca 41%) + 0,4 L ha-1 boro (B 14 %). Las plantas se cultivaron durante 90 días en macetas de plástico con 3 kg de arena y vermiculita (v / v) tratadas en autoclave a 121°C durante 1 h. El experimento se realizó en un diseño completamente aleatorizado con cinco repeticiones en un invernadero. Se evaluaron los parámetros de rendimiento de soja, tales como, peso seco del brote, raíz y total; altura de la planta, nitrógeno en el brote; número y peso seco de los nódulos; índice de clorofila en las hojas; cantidad de mazorcas por planta (NPPL); número de granos por pod (NGP); y número de granos por planta (NGPL). La adición de Ca + B aumentó significativamente NPPL, NGPL y NGP. El NPPL y NGPL se incrementaron significativamente con 600 mL ha-1 del inoculante. La dosis de 600 ml ha-1 del inoculante combinado con Ca + B estimuló significativamente NPPL, NGPL y NGP. Se concluye que la productividad de la soya se incrementó con la adición de 600 mL ha-1 de inoculante, en combinación con Ca y B.

scholarly journals Role of oxyR from Sinorhizobium meliloti in Regulating the Expression of Catalases

2005 ◽  
Vol 37 (6) ◽  
pp. 421-428 ◽  
Author(s):  
Li Luo ◽  
Ming-Sheng Qi ◽  
Shi-Yi Yao ◽  
Hai-Ping Cheng ◽  
Jia-Bi Zhu ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Sinorhizobium Meliloti ◽  
Wild Type Strain ◽  
Reduced Form ◽  
Insertion Mutant ◽  
Transcriptional Level ◽  
Oxygen Species ◽  
E Coli ◽  
Catalase Peroxidase

AbstractThe process of symbiotic nitrogen fixation results in the generation of reactive oxygen species such as the superoxide anion (O2-) and hydrogen peroxide (H2O2). The response of rhizobia to these toxic oxygen species is an important factor in nodulation and nitrogen fixation. In Sinorhizobium meliloti, one oxyR homologue and three catalase genes, katA, katB, and katC were detected by sequence analysis. This oxyR gene is located next to and divergently from katA on the chromosome. To investigate the possible roles of oxyR in regulating the expression of catalases at the transcriptional level in S. meliloti, an insertion mutant of this gene was constructed. The mutant was more sensitive and less adaptive to H2O2 than the wild type strain, and total catalase/peroxidase activity was reduced approximately fourfold with the OxyR mutation relative to controls. The activities of KatA and KatB and the expression of katA::lacZ and katB::lacZ promoter fusions were increased in the mutant strain compared with the parental strain grown in the absence of H2O2, indicating that katA and katB are repressed by OxyR. However, when exposed to H2O2, katA expression was also increased in both S. meliloti and Escherichia coli. When exposed to H2O2, OxyR is converted from a reduced to an oxidized form in E. coli. We concluded that the reduced form of OxyR functions as a repressor of katA and katB expression. Thus, in the presence of H2O2, reduced OxyR is converted to the oxidized form of OxyR that then results in increased katA expression. We further showed that oxyR expression is autoregulated via negative feedback.

Enhanced attachment of Bradyrhizobium japonicum to soybean through reduced root colonization of internally seedborne microorganisms

2000 ◽  
Vol 46 (7) ◽  
pp. 600-606 ◽  
Author(s):  
Nathan W Oehrle ◽  
Dale B Karr ◽  
Robert J Kremer ◽  
David W Emerich
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Seed Germination ◽  
Bradyrhizobium Japonicum ◽  
Soybean Seed ◽  
Seedling Development ◽  
Penicillin G ◽  
Root Tip ◽  
Surface Sterilization ◽  
Soybean Seedlings

Internally seedborne microorganisms are those surviving common surface sterilization procedures. Such microbes often colonize the radicle surface of a germinating soybean (Glycine max) seed, introducing an undefined parameter into studies on attachment and infection by Bradyrhizobium japonicum. Bacterial isolates from surface-sterilized soybean seed, cv. Williams 82 and cv. Maverick, used in our studies, were identified as Agrobacterium radiobacter, Aeromonas sp., Bacillus spp., Chryseomonas luteola, Flavimonas oryzihabitans, and Sphingomonas paucimobilis. Growth of these microbes during seed germination was reduced by treating germinating seeds with 500 µg/mL penicillin G. The effects of this antibiotic on seedling development and on B. japonicum 2143 attachment, nodulation, and nitrogen fixation are reported here. Penicillin G treatment of seeds did not reduce seed germination or root tip growth, or affect seedling development. No differences in nodulation kinetics, nitrogen fixation onset or rates were observed. However, the number of B. japonicum attached to treated intact seedlings was enhanced 200-325%, demonstrating that other root-colonizing bacteria can interfere with rhizobial attachment. Penicillin G treatment of soybean seedlings can be used to reduce the root colonizing microbes, which introduce an undefined parameter into studies of attachment of B. japonicum to the soybean root, without affecting plant development.Key words: internally seedborne microorganisms, penicillin G, Bradyrhizobium japonicum, microbial attachment, soybean (Glycine max).

scholarly journals Identification of Sigma Factor 54-Regulated Small Non-Coding RNAs by Employing Genome-Wide and Transcriptome-Based Methods in Rhizobium Strains

2021 ◽  
Author(s):  
Kasthuri Rajendran ◽  
Vikram Kumar ◽  
Ilamathi Raja ◽  
Manoharan Kumariah ◽  
Jebasingh Tennyson
Keyword(s):  
Nitrogen Fixation ◽  
Sigma Factor ◽  
Bradyrhizobium Japonicum ◽  
Symbiotic Association ◽  
Transcriptome Data ◽  
Free Living ◽  
Rhizobium Strains ◽  
Legume Symbiosis ◽  
Biological Nitrogen

Abstract Rhizobium-legume symbiosis is considered as the major contributor of biological nitrogen fixation. In the present study, we have identified sigma factor 54-regulated sRNAs from the genome of five Rhizobium strains and integrated with the free-living and symbiotic specific transcriptome data to identify the novel putative sRNAs that are over expressed during the regulation of nitrogen fixation. A total of 1059 sRNAs were predicted from each genome of the select set of Rhizobium strains and 1,375 sRNAs were predicted from the transcriptome data of Bradyrhizobium japonicum. Target mRNA analysis revealed the functional role of putative novel sRNAs from different free-living and symbiotic strains. Those novel sRNAs were inferred to target several nodulation and nitrogen fixation genes including nodC, nodJ, nodY, nodJ, nodM, nodW, nodZ, nifD, nifN, nifQ, fixK, fixL, Fdx, nolB, and several cytochrome proteins. Further, sRNAs of Bradyrhizobium japonicum which targeted the regulatory genes of nitrogen fixation were experimentally confirmed with semi-quantitative reverse transcription polymerase chain reaction. Predicted target mRNAs were functionally classified based on the COG analysis and GO annotations. Studies on this sigma factor 54-regulated sRNA identification could be a better method to relate the role of sRNAs in nitrogen metabolism during free-living and symbiotic association with legumes.

scholarly journals Bradyrhizobium and azospirllum interaction in soybean cultivars (Glycine Max (l.) Merrill) and their effects on productivity

2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
T. O. D. Gonzaga ◽  
C. C. Vilar ◽  
A. S. Silva Filho ◽  
V. L. Silva
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Azospirillum Brasilense ◽  
Productive Performance ◽  
Diazotrophic Bacteria ◽  
Glycine Max L ◽  
Major Producer ◽  
Growth Promoting ◽  
Biological Nitrogen

Brazil is a major producer of soybeans and a model in the use of biological nitrogen fixation, however, few authors are investigating the use of more than one genus of bacteria acting alone and / or together. An example is the use of the diazotrophic bacteria of the genus Bradyrhizobium and Azospirillum, the latter besides the fixation presents growth promoting function. Thus, the objective of this bibliographic review and to verify the influence on the productive performance Bradyrhizobium japonicum and Azospirillum brasilense, in the soybean crop. 

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