Isolation and characterization of Rhizobium sp. from a collar rot tolerant groundnut (Arachis hypogaea L.) variety (original) (raw)
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Objectives: To isolate and identify the crop specific Rhizobium strains for Glycine max from Bhadrachalam forest lands by an indigenous novel strategy to reduce the input cost in exploration of compatible strains for soybean avoiding serious constrain of bio-fertilizers i.e., shelf life. Materials and Methods: Soil samples were collected randomly from 40 different locations of Bhadrachalam forest and sown with ground nut seeds in triplets. Five out of 40 samples which supported the best plant growth were taken for further investigations. The NPK and micronutrient levels of all the soil samples were found to be comparatively similar. This may be because of the fact that all samples have been taken from same geographic region. Rhizobial strains from the root nodules of these five samples were isolated and maintained in pure cultures. Broths of each pure culture were inoculated on the seeds sown in sterile soil and controls were maintained. Findings: The results showed that the inoculated Rhizobia tremendously improved the plant growth when compared with control. Further phylogenetic analysis revealed that the contributing organisms were Rhizobium leguminosarum, Rhizobium trifolii, Rhizobium meliloti, Rhizobium phaseoli and Bradyrhizobiumjaponicum. These Rhizobial species in the pure form exhibited high rate of plant growth at lab conditions followed by improved growth in low vegetative agriculture soils of the same geography. The 16S rRNA gene sequences revealed the fact that soil sample 3 contain abundant Rhizobium leguminosarum sp., with 99% similarity. The sample 1, 2, 4 and 5 contain abundant levels of Rhizobium trifolii, Rhizobium meliloti, Rhizobium phaseoli and Bradyrhizobiumjaponicum respectively. Application: Therefore this method could be applied for the preliminary screening of compatible, species specific strains for any leguminous plants making the process easy and less expensive
Current Agriculture Research Journal
Plant growth promoting rhizobacteria (PGPR) have been extensively employed as biofertilizers to enhance the soil nutrition for several crop plants. Rhizobacteria with beneficial effects for plants could therefore be used to reduce the dependence on synthetic chemical fertilizers in conventional agriculture. Within this study, we have explored for isolation of potential PGPR for groundnut crop from agricultural fields of Saurashtra region, Gujarat. A total of forty-two isolates from rhizospheric soil with different colony characteristics were isolated. All the strains were tested for plant growth promoting (PGP) traits to observe their properties and potential for plant growth promoting of all forty-two isolates. Plant growth promoting traits such as indole acetic acid (IAA), hydrogen cyanide (HCN), ammonia production, phosphate solubilisation and gibberellins production were performed. Thirty-four isolates produced IAA in the range of 20.7–133 µg/mL, seventeen isolates were positive...
Antonie van Leeuwenhoek, 2014
A Gram-negative, white, non-motile, rod shaped bacterial strain BN-19 T was isolated from a root nodule of groundnut (Arachis hypogaea) in Pakistan. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain BN-19 T formed a subclade in the genus Rhizobium together with Rhizobium alkalisoli CCBAU 01393 T , Rhizobium vignae CCBAU 05176 T , Rhizobium huautlense SO2 T and Rhizobium tarimense PL-41 T with sequence similarities of 97.5, 97.3, 97.2 and 97.1 % respectively. Sequence analysis of housekeeping genes atpD, glnII and recA (with sequence similarities of B92 %) confirmed the unique position of BN-19 T in the genus Rhizobium. DNA-DNA relatedness between the strain BN-19 T and R. alkalisoli CCBAU 01393 T , R. vignae CCBAU 05176 T , R. huautlense SO2 T and R. tarimense PL-41 T were 20.6, 22.5, 15.9 and 20.5 % respectively, further confirming that BN-19 T represents a novel species in the genus Rhizobium. The DNA G ? C content was 60.1 mol%. The dominant fatty acids of strain BN-19 T were C 19:0 cyclo x8c, summed feature 2 (C 14:0 3OH and/or C 16:1 iso I) and summed feature 8 (C 18:1 x7c). Some phenotypic features also differentiate the strain BN-19 T from the related species. On the basis of these results, strain BN-19 T is considered to represent a novel species in the genus Rhizobium, for which the name Rhizobium pakistanensis sp. nov. is proposed. The type strain is BN-19 T (=LMG 27895 T = CCBAU 101086 T). Keywords Arachis hypogaea Á Rhizobia Á Housekeeping genes Á Polyphasic taxonomy The GenBank/EMBL/DDBJ sequence accession numbers of strain BN-19 T (=LMG 27895 T = CCBAU 101086 T) for the partial 16S rRNA, atpD, glnII and recA gene are AB854065, AB856324, AB856325 and AB855792, respectively.
Current Microbiology, 2020
Rhizobium are nitrogen-fixing bacteria which possess the nif gene that codes for the nitrogenase enzyme involved in the reduction of atmospheric dinitrogen (N 2) to ammonia. Thirty rhizobial strains were identified from ten groundnut plant root nodules collected from semi-arid regions of Rajasthan, India. The isolates were initially identified on the basis of morphological, biochemical, and molecular characteristics. These rhizobium strains were further screened for plant growth promoting activities. Twenty-eight strains were able to produce indole acetic acid, nine strains could solubilize phosphate, and twenty-nine strains exhibited positive results for siderophore and ammonia production. All the bacterial strains were able to efficiently nodulate the groundnut under pot conditions and based on multiple PGP activities six strains were selected for field evaluation. Field experiments confirmed the effectiveness of these selected rhizobium strains resulted in significantly higher nodule number, nodule dry weight, grain yield, and yield components of inoculated plants. Inoculation of the rhizobium strain GN223 followed by GN221 resulted in high yield and field efficiency. Isolation of effective microbial strains is the prerequisite to increase the yield which is evident from the field data of the present study. Hence, these strains might serve as proficient inoculants. Abbreviations PCR-RFLP Polymerase chain reaction-restriction fragment length polymorphism ARDRA Amplified 16S ribosomal DNA restriction analysis UPGMA Unweighted pair group method with arithmetic mean Electronic supplementary material The online version of this article (
African Journal of Microbiology Research
A total of eighty one (81) rhizobial isolates were recovered from root nodules of cowpea (Vigna unguiculata L. Walp.) and groundnut (Arachis hypogaea L.) grown in soils collected from eight different sites (Hawassa, Wondogenet, Chofa, Badawacho, Bodity, Gofa, Ziway, and Alemtena) in Ethiopia with no known history of inoculation. The test isolates together with seven reference strains belonging to five genera including Rhizobium, Ensifer, Mesorhizobium, Bradyrhizobium and Azorhizobium were characterized using ninety phenotypic traits. Thirty one isolates (38%) were found to be fast growers while fifty isolates (62%) were slow growers. The majority of the isolates showed an intrinsic resistance to antibiotics (µg/ml), Chloramphenicol (5 and 15), Lincomycin (100), Novobiocin (0.5 and 1.5), and Erythromycin (10 and 20) and to heavy metals manganese sulphate (500) and copper chloride (100). Most isolates did not tolerate NaCl concentration >3% (w/v) and high temperature (45°C). Dendrogram was constructed by applying the unweighted pair group method with arithmetic means (UPGMA) using NTSYSpc Version 2.1. They were grouped into seven clusters and eight unclustered positions, when 82% relative similarity was used as a cut point. Fifty eight percent of the test isolates were grouped with Bradyrhizobium japonicum and Bradyrhizobium elkanii superclades, thus indicating that rhizobia nodulating cowpea and groundnut are delineated within a branch that defines Bradyrhizobium genus. To elucidate the precise taxonomic positions of the isolates, further genetic studies are required using modern molecular biological methods.
EFFICACY OF RHIZOBIUM STRAINS FOR GROUNDNUT INOCULATION UNDER RAIN FED CONDITIONS
The efficacy of symbiotic association between three Rhizobium strains i.e. B (TAL-1371, C (Tal-1000) and 0 (NC-92) and two groundnut genotypes viz. V 1 (ICG-4993) and V2 (ICG-732) was studied in a field trial under rain-fed conditions of Pothowar in a semi-arid environment. Inoculation increased symbiotic and yield traits of ground nut genotypes. Plants inoculated with strain 0 (NC-92) had significantly more nodules plant", nodule dry weight plant", N content of nodules, roots and shoots of both V1 (ICG-4993) and V2 (ICG-7326) than that of strain B (TAL-1371) or strain C (TAL-1000). The strain 0 (NC-92) exhibited specificity and positively interacted in influencing symbiotic traits of V 2 (ICG-7326). Plants inoculated with strain 0 (NC-92) produced more pods plant", pods and biological yield ha' compared to strain B (TAL-1371) or strain C (TAL-1000). The effect of strain B (TAL-1371) and strain C (TAL-1000) was statistically same on symbiotic and yield traits of groundnut genotypes. Rhizobium strain 0 (NC-92) was found superior to strain B (TAL-1371) or strain C (TAL-1000) in their effects on symbiotic traits and groundnut yield.
Efficacy of Various Rhizobium Strains to Different Varieties of Groundnut [Arachis hypogea L.)
Pakistan Journal of …, 1999
Groundnut variety BARD-699 produced significantly the most promising yield than that of variety BARI-89 at Attock, Fatehjang and NARC, Islamabad. Rhizobium strains, NC-92 was found to be less efficient as compared to TAL-1000; TAL-1371. Nodule dry mass and number of pods per plant were much higher than that of control treatment. Although a significant difference in growth and yield of both the varieties due to Rhizobium inoculation was observed but on average basis TAL-1000 and TAL-1371 gave significantly better response for both the varieties in improving growth and yield at all sites. Nevertheless, future prospects for groundnut production are good in Pakistan if the farmers are realized to practice inoculation technology in their fields.
Legume Research, 2016
Plant growth-promoting rhizobacteria (PGPR) thrive in the rhizosphere of plants and play a beneficial role in plant growth, and development along with biocontrol activities. The present study was undertaken with the aim of developing rhizobacterial inoculants for groundnut for enhancement of growth and yield and suppression of major soil-borne fungal diseases caused by Sclerotium rolfsii (stem rot) and Aspergillus niger (collar rot). Out of a total of 154 rhizobacterial isolates obtained from groundnut rhizosphere, 78 isolates were selected on the basis of in vitro antifungal activities against three major soil-borne fungal pathogens of groundnut, i.e. Aspergillus niger, Aspergillus flavus and Sclerotium rolfsii. The selected isolates were further screened for the production of 2,4-Diacetylphloroglucinol (2,4-DAPG) by the gene specific PCR amplification of phlD gene. A total of 11 rhizobacterial isolates were found to have DAPG-producing genes and selected for further studies. Gene ...
Bacteria related to Bradyrhizobium yuanmingense from Ghana are effective groundnut micro-symbionts
The identification of locally-adapted rhizobia for effective inoculation of grain legumes in Africa's semiarid regions is strategic for developing and optimizing cheap nitrogen fixation technologies for smallholder farmers. This study was aimed at selecting and characterising effective native rhizobia, from Ghanaian soils for groundnut (Arachis hypogaea L.) inoculation. From surface-disinfected root nodules of cowpea and groundnut plants grown on farmers' fields, 150 bacterial isolates were obtained, 30 of which were eventually found to nodulate groundnut plants. After testing the symbiotic potential of these isolates on groundnut on sterilized substrate, seven of them, designated as KNUST 1001-1007, were evaluated in an open field pot experiment using 15 Nlabelled soil. Although 15 N dilution analyses did not indicate differences among treatments in the proportion of nitrogen (N) derived from the atmosphere (%Ndfa), all seven strains increased total N derived from N 2 fixation by inoculated groundnut plants as compared to the non-inoculated control. Inoculation with KNUST 1002 led to total N accumulation as high as that of the groundnut reference strain 32H1. Genetic characterisation of the isolates by sequence analysis of 16S rRNA gene, 16S -23S rRNA intergenic transcribed spacer (ITS) region and nodC gene revealed that isolates KNUST 1003 and 1007 were related to Rhizobium tropici, a common bean symbiont. The other five isolates, including KNUST 1002 belonged to the Bradyrhizobium genus, being closely related to Bradyrhizobium yuanmingense. Therefore, this study revealed novel native Ghanaian rhizobia with potential for the development of groundnut inoculants.