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Hoben HJ, Aung NN, Somasegaran P, Kang UG. Oils as adhesives for seed inoculation and their influence on the survival of Rhizobium spp. and Bradyrhizobium spp. on inoculated seeds. World J Microbiol Biotechnol 2014; 7:324-30. [PMID: 24425019 DOI: 10.1007/bf00329398] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Mineral oil, peanut oil and soybean oil were compared with water and gum arabic for their suitability as adhesives for seed inoculation with peat inoculants. Inoculated seeds were stored at 4, 28 and 34°C, and sampled after 1, 3 and 9 days to determine the survival of rhizobia. Germination and nodulation tests were performed on the inoculated seeds. Results showed that oils were suitable adhesives for peat inoculants. Although the oils initially bound less inoculant to the seed, the number of surviving rhizobia was similar to that obtained by the gum arabic treatment after storage at 28 and 34°C for 3 and 9 days. An interesting finding of this experiment was that peanut and soybean oils were superior to gum arabic in supporting significantly higher numbers of chickpea rhizobia at 34°C. Inoculated seeds tested for germination and nodulation showed no adverse effects from the oil treatments. Oils hold good potential as adhesives for seed application in inoculation technology.
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Somasegaran P, Bohlool BB. Single-Strain versus Multistrain Inoculation: Effect of Soil Mineral N Availability on Rhizobial Strain Effectiveness and Competition for Nodulation on Chick-Pea, Soybean, and Dry Bean. Appl Environ Microbiol 2010; 56:3298-303. [PMID: 16348337 PMCID: PMC184945 DOI: 10.1128/aem.56.11.3298-3303.1990] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nitrogen-fixing effectiveness of multistrain inoculants was found to be determined by both the effectiveness of the component strains and the percentage of the nodules occupied by them. Multistrain formulations were always either as good as the most effective single-strain inoculant or intermediate between the most and the least effective. The percentage of nodules occupied and the amount of nitrogen fixed by the component strains of a multistrain inoculant showed highly significant linear correlation. The availability of soil N had a significant influence on the nitrogen fixation potential of each strain. The mineral N status of the soil was clearly a significant factor in affecting the competition pattern of Rhizobium loti (chick-pea) and Bradyrhizobium japonicum strains. Differences between the effectiveness of strains were masked under conditions of soil N availability. However, when soil N was immobilized with sugarcane bagasse, the differences became significant. In the chick-pea system, R. loti TAL 1148 (Nit 27A8) was the most effective but not the most competitive of the three strains used. In the soybean and dry bean systems, B. japonicum TAL 102 (USDA 110) and R. leguminosarum bv. phaseoli TAL 182, respectively, were consistently the most effective and, more often than not, the most competitive of the strains used for each species.
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Affiliation(s)
- P Somasegaran
- NifTAL Project, University of Hawaii, 1000 Holomua Avenue, Paia, Hawaii 96779
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Hoben HJ, Somasegaran P. Comparison of the Pour, Spread, and Drop Plate Methods for Enumeration of Rhizobium spp. in Inoculants Made from Presterilized Peat. Appl Environ Microbiol 2010; 44:1246-7. [PMID: 16346141 PMCID: PMC242176 DOI: 10.1128/aem.44.5.1246-1247.1982] [Citation(s) in RCA: 243] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inoculants prepared with presterilized peat were enumerated by the pour, spread, and drop plate techniques. Results indicated that the three plating methods were interchangeable. The drop plate method was preferred because of its economy in materials and labor.
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Affiliation(s)
- H J Hoben
- NifTAL Project, Department of Agronomy and Soil Science, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, Hawaii 96822
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Somasegaran P, Woolfenden R, Halliday J. Suitability of oven-dried root nodules forRhizobiumstrain identification by immunofluorescence and agglutination. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1983.tb01323.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rice DJ, Somasegaran P, Macglashan K, Bohlool BB. Isolation of Insertion Sequence IS
RLd
TAL1145-1 from a
Rhizobium
sp. (
Leucaena diversifolia
) and Distribution of Homologous Sequences Identifying Cross-Inoculation Group Relationships. Appl Environ Microbiol 1994; 60:4394-403. [PMID: 16349459 PMCID: PMC201998 DOI: 10.1128/aem.60.12.4394-4403.1994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Insertion sequence (IS) element IS
RLd
TAL1145-1 from
Rhizobium
sp. (
Leucaena diversifolia
) strain TAL 1145 was entrapped in the
sacB
gene of the positive selection vector pUCD800 by insertional inactivation. A hybridization probe prepared from the whole 2.5-kb element was used to determine the distribution of homologous sequences in a diverse collection of 135
Rhizobium
and
Bradyrhizobium
strains. The IS probe hybridized strongly to Southern blots of genomic DNAs from 10 rhizobial strains that nodulate both
Phaseolus vulgaris
(beans) and
Leucaena leucocephala
(leguminous trees), 1
Rhizobium
sp. that nodulates
Leucaena
spp., 9
R. meliloti
(alfalfa) strains, 4
Rhizobium
spp. that nodulate
Sophora chrysophylla
(leguminous trees), and 1 nonnodulating bacterium associated with the nodules of
Pithecellobium dulce
from the
Leucaena
cross-inoculation group, producing distinguishing IS patterns for each strain. Hybridization analysis revealed that IS
RLd
TAL1145-1 was strongly homologous with and closely related to a previously isolated element, IS
Rm
USDA1024-1 from
R. meliloti
, while restriction enzyme analysis found structural similarities and differences between the two IS homologs. Two internal segments of these IS elements were used to construct hybridization probes of 1.2 kb and 380 bp that delineate a structural similarity and a difference, respectively, of the two IS homologs. The internal segment probes were used to analyze the structures of homologous IS elements in other strains. Five types of structural variation in homolog IS elements were found. The predominate IS structural type naturally occurring in a strain can reasonably identify the strain's cross-inoculation group relationships. Three IS structural types were found in
Rhizobium
species that nodulate beans and
Leucaena
species, one of which included the designated type IIB strain of
R. tropici
(CIAT 899). Weak homology to the whole IS probe, but not with the internal segments, was found with two
Bradyrhizobium japonicum
strains. The taxonomic and ecological implications of the distribution of IS
RLd
TAL1145-1 are discussed.
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Affiliation(s)
- D J Rice
- University of Hawaii, NifTAL Center, Paia, Maui, Hawaii 96779
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Hoben HJ, Somasegaran P, Boonkerd N, Gaur YD. Polyclonal antisera production by immunization with mixed cell antigens of different rhizobial species. World J Microbiol Biotechnol 1994; 10:538-42. [PMID: 24421129 DOI: 10.1007/bf00367662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/18/1994] [Accepted: 04/22/1994] [Indexed: 10/26/2022]
Abstract
Somatic antigens of Bradyrhizobium japonicum, Rhizobium sp. (Cicer arietinum) and Rhizobium sp. (Leucaena leucocephala) were prepared as standard, single-species type from cultured cells. Equal numbers of the cells of these rhizobia were then combined to obtain a mixed-rhizobial-species antigen preparation. Rabbits were immunized either with the standard, single-species type or with the mixed-rhizobial-species antigen preparations. The antisera developed from the mixed antigen immunization contained antibodies for all three rhizobial species, detectable at agglutination titres of over 800. The mixed-rhizobial-species antisera were made species specific by cross-absorption. The cross-absorbed and the mixed-rhizobial-species antisera were generally similar in quality for strain identification by agglutination, fluorescent antibodies, immunoblot and ELISA. A 66% reduction in cost was estimated for the production of antisera by immunization with mixed-rhizobial-species antigen.
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Kang UG, Somasegaran P, Hoben HJ, Bohlool BB. Symbiotic Potential, Competitiveness, and Serological Properties of
Bradyrhizobium japonicum
Indigenous to Korean Soils. Appl Environ Microbiol 1991; 57:1038-45. [PMID: 16348454 PMCID: PMC182842 DOI: 10.1128/aem.57.4.1038-1045.1991] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The symbiotic potential of
Bradyrhizobium japonicum
isolates indigenous to seven Korean soils was evaluated by inoculating soybeans with 10- and 1,000-fold-diluted soil suspensions (whole-soil inocula). At both levels, significant differences in the symbiotic potential of the indigenous
B. japonicum
isolates were demonstrated. The relationship between rhizobial numbers in the whole-soil inocula (
x
) and nitrogen fixation parameters (
y
) was best predicted by a straight line (
y
=
a
+
bx
) when the numbers in the inocula were 100 to 10,000 ml
-1
, while the power curve (
y
=
ax
b
) predicted the variation when the numbers were 1 to 100 ml
-1
. Thirty isolates from three soils showed wide differences in effectiveness (measured as milligrams of shoot N per plant), and several were of equal or greater effectiveness than reference strain
B. japonicum
USDA 110 on soybean cultivars Clark and Jangbaekkong. On both of the soybean cultivars grown in a Hawaiian mollisol, the Korean
B. japonicum
isolate YCK 213 and USDA 110 were of equal effectiveness; USDA 110 was the superior strain in colonization (nodule occupancy). Korean isolates YCK 117 and YCK 141 were superior colonizers compared with USDA 110. However,
B. japonicum
USDA 123 was the superior colonizer compared with isolates YCK 213, YCK 141, and YCK 117. In an immunoblot analysis of 97 indigenous Korean isolates of
B. japonicum
, 41% fell into the USDA 110 and USDA 123 serogroups. Serogroups USDA 110 and USDA 123 were represented in six of the seven soils examined. In one Korean soil, 100% of the
B. japonicum
isolates reacted only with antisera of YCK 117, an isolate from the same soil.
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Affiliation(s)
- U G Kang
- NifTAL Project, University of Hawaii, 1000 Holomua Avenue, Paia, Hawaii 96779
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Somasegaran P, Martin RB. Symbiotic Characteristics and
Rhizobium
Requirements of a
Leucaena leucocephala
×
Leucaena diversifolia
Hybrid and Its Parental Genotypes. Appl Environ Microbiol 1986; 52:1422-4. [PMID: 16347248 PMCID: PMC239247 DOI: 10.1128/aem.52.6.1422-1424.1986] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In 56-day-old plants,
Leucaena leucocephala
and its hybrid with
L. diversifolia
showed 100% more total N than did
L. diversifolia.
Significant (
P
< 0.01) host-inoculation interaction in total N was 14.4% of the total phenotypic variation. The most effective and competitive
Rhizobium
sp. for the leucaenas was TAL 1145. Three-strain mixed inoculation was inferior to TAL 1145 alone.
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Affiliation(s)
- P Somasegaran
- NifTAL Project, University of Hawaii, Paia, Hawaii 96779
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Somasegaran P. Inoculant Production with Diluted Liquid Cultures of
Rhizobium
spp. and Autoclaved Peat: Evaluation of Diluents,
Rhizobium
spp., Peats, Sterility Requirements, Storage, and Plant Effectiveness. Appl Environ Microbiol 1985; 50:398-405. [PMID: 16346860 PMCID: PMC238633 DOI: 10.1128/aem.50.2.398-405.1985] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fully grown broth cultures of various fast- and slow-growing rhizobia were deliberately diluted with various diluents before their aseptic incorporation into autoclaved peat in polypropylene bags (aseptic method) or mixed with the peat autoclaved in trays (tray method). In a factorial experiment with the aseptic method, autoclaved and irradiated peat samples from five countries were used to prepare inoculants with water-diluted cultures of three
Rhizobium
spp. When distilled water was used as the diluent, the multiplication and survival of rhizobia in the peat was similar to that with diluents having a high nutrient status when the aseptic method was used. In the factorial experiment, the mean viable counts per gram of inoculant were log 9.23 (strain TAL 102) > log 8.92 (strain TAL 82) > log 7.89 (strain TAL 182) after 24 weeks of storage at 28�C. The peat from Argentina was the most superior for the three
Rhizobium
spp., with a mean viable count of log 9.0 per g at the end of the storage period. The quality of inoculants produced with diluted cultures was significantly (
P
= 0.05) better with irradiated than with autoclaved peat, as shown from the factorial experiment. With the tray method, rhizobia in cultures diluted 1,000-fold or less multiplied and stored satisfactorily in the presence of postinoculation contaminants, as determined by plate counts, membrane filter immunofluorescence, and plant infection procedures. All strains of rhizobia used in both the methods showed various degrees of population decline in the inoculants when stored at 28�C. Fast- and slow-growing rhizobia in matured inoculants produced by the two methods showed significant (
P
< 0.01) decline in viability when stored at 4�C, whereas the viability of some strains increased significantly (
P
< 0.01) at the same temperature. The plant effectiveness of inoculants produced with diluted cultures and autoclaved peat did not differ significantly from that of inoculants produced with undiluted cultures and gamma-irradiated peat.
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Affiliation(s)
- P Somasegaran
- NifTAL Project, Department of Agronomy and Soil Science, University of Hawaii, Honolulu, Hawaii 96822
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Somasegaran P, Reyes VG, Hoben HJ. The influence of high temperatures on the growth and survival of Rhizobium spp. in peat inoculants during preparation, storage, and distribution. Can J Microbiol 1984. [DOI: 10.1139/m84-004] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gamma-irradiated peat was used to prepare inoculants for 10 different species of tropical legumes. These inoculants were sent to cooperators in 14 cities in 13 tropical countries. Each cooperator received a package containing a maximum recording thermometer, plating-media components, special instruction sheets, and inoculants. Control experiments were pursued in the laboratory by exposing the various inoculants to 28, 37, and 46 °C. Temperatures reached in the inoculants during their transportation varied from 26 (Mexico) to 45 °C (Kenya). Arrival time of the inoculants ranged from 6 days (Hissar, India) to 54 days (St. Augustine, West Indies). Although a total loss of viability was reported for the chick-pea inoculant (Saudia Arabia) and a severe decrease in two others (bean and lentil inoculants in Kenya and Saudi Arabia, respectively), over 90% of the inoculants received had viable counts in excess of 1 × 108 cells per gram of moist peat. Laboratory data indicated that 28 °C was optimal for multiplication to maximal numbers in excess of 1 × 1010 cells per gram of moist peat. Six inoculants studied for long-term storage showed excellent quality for 24 weeks at 28 °C. At 37 °C the cell multiplication was comparable with that at 28 °C with 8 of the 10 strains only during the 1st week. For all strains, 46 °C was lethal. Large reductions in viable counts were observed during inoculant preparation when broth cultures were added to peat.
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Abstract
Experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. Liquid cultures of
Rhizobium japonicum
and
Rhizobium phaseoli
were diluted to give 10
8
, 10
7
, or 10
6
cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. The variously diluted cultures were incorporated into gamma-irradiated peat, and the numbers of viable rhizobia were determined at intervals. In all of the inoculant formulations, the numbers of rhizobia reached similarly high ceiling values by 1 week after incorporation, irrespective not only of the number of cells added initially but also of the nature of the diluent. During week 1 of growth, similar multiplication patterns of the diluted liquid cultures were observed in two different peats. Numbers of rhizobia surviving in the various inoculant formulations were not markedly different after 6 months of storage at 28°C. The method of inoculant preparation did not affect the nitrogen fixation effectiveness of the
Rhizobium
strains.
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Affiliation(s)
- P Somasegaran
- NifTAL Project, Department of Agronomy and Soil Science, University of Hawaii, Honolulu, Hawaii 96822
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