Journal articles on the topic 'Rhizobiota'
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1
Widijanto, Hery, and Suntoro Suntoro. "Pembuatan Demplot Budidaya Tanaman Jagung Dalam Menambah Masa Tanam Di Lahan Kering Dengan Memanfaatkan Pupuk Organik." PRIMA: Journal of Community Empowering and Services 3, no. 1 (June 30, 2019): 28. http://dx.doi.org/10.20961/prima.v3i1.36111.
Abstract:
Program IbM ini bekerjasama dengan dua mitra, yaitu: (1) UKM Peternakan Puyuh “Agribird ”, dan (2) Kelompok Tani “Mekar Tani”. Mitra (1) dan Mitra (2) berlokasi di dukuh Gunung Wijil, Desa Ngringo, Kec. Jaten, Kab. Karanganyar, Jawa Tengah dengan jarak tempuh sekitar ± 3,5 km. Permasalahan utama yang dihadapi oleh mitra usaha „Agribird‟ adalah produksi limbah ternak puyuh yang sangat tinggi, yaitu sekitar 300 kg limbah per hari. Produksi limbahnya sangat tinggi per hari, maka kemampuan produksi limbah jauh melibihi dari kemampuan untuk memanfaatkannya. Bila limbah ini dibuang langsung ke badan sungai terdekat, maka akan mencemari air sungai, sedangkan bila limbah akan diubah menjadi pupuk organik, maka diperlukan teknologi pembuatan pupuk organik. Permasalahan Mitra 2 (Mekar Tani) : lahan yang tiap tahunnya ditanami padi selama 2 kali musim tanam. Musim tanam yang ke-3 diberokan (tidak ditanami), termasuk sawah-sawah petani yang ada di sekitarnya.Solusi yang ditawarkan untuk mengatasi permasalahan utama yang dihadapi mitra (1) adalah teknologi pembuatan pupuk organik yang dapat digunakan sebagai pupuk organik yang sangat bermutu yang dapat digunakan sebagai pupuk organik bagi usaha budidaya tanaman jagung pada mitra (2) yang dapat menambah masa tanam.Kegiatan ini merupakan penerapan Biofilmed Fertilizer yang telah diujikan pada penelitian Pengembangan Biofilmed Biofertilizer Beragens Hayati dari Konsorsia Rhizobiota Bawang Merah (RG Strategis Nasional 2015-2016) serta Teknologi Pengelolaan Limbah untuk Pakan dan Pupuk pada Sistem Pertanian Terpadu Berbasis Perikanan, Peternakan Puyuh dan Sayur Organik (RISTEK - Insinas 2014-2015).
2
Wackett, Lawrence P. "Rhizobia." Environmental Microbiology 6, no. 1 (December 17, 2003): 93. http://dx.doi.org/10.1111/j.1462-2920.2004.00564.x.
3
Fleischman, Darrell, and David Kramer. "Photosynthetic rhizobia." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1364, no. 1 (April 1998): 17–36. http://dx.doi.org/10.1016/s0005-2728(98)00011-5.
4
Malhotra, Pooja, Saumik Basu, Benjamin W. Lee, Liesl Oeller, and David W. Crowder. "Effects of Soil Rhizobia Abundance on Interactions between a Vector, Pathogen, and Legume Plant Host." Genes 15, no. 3 (February 22, 2024): 273. http://dx.doi.org/10.3390/genes15030273.
Abstract:
Soil rhizobia promote nitrogen fixation in legume hosts, maximizing their tolerance to different biotic stressors, plant biomass, crop growth, and yield. While the presence of soil rhizobia is considered beneficial for plants, few studies have assessed whether variation in rhizobia abundance affects the tolerance of legumes to stressors. To address this, we assessed the effects of variable soil rhizobia inoculum concentrations on interactions between a legume host (Pisum sativum), a vector insect (Acyrthosiphon pisum), and a virus (Pea enation mosaic virus, PEMV). We showed that increased rhizobia abundance reduces the inhibitory effects of PEMV on the nodule formation and root growth in 2-week-old plants. However, these trends were reversed in 4-week-old plants. Rhizobia abundance did not affect shoot growth or virus prevalence in 2- or 4-week-old plants. Our results show that rhizobia abundance may indirectly affect legume tolerance to a virus, but effects varied based on plant age. To assess the mechanisms that mediated interactions between rhizobia, plants, aphids, and PEMV, we measured the relative expression of gene transcripts related to plant defense signaling. Rhizobia concentrations did not strongly affect the expression of defense genes associated with phytohormone signaling. Our study shows that an abundance of soil rhizobia may impact a plant’s ability to tolerate stressors such as vector-borne pathogens, as well as aid in developing sustainable pest and pathogen management systems for legume crops. More broadly, understanding how variable rhizobia concentrations can optimize legume-rhizobia symbiosis may enhance the productivity of legume crops.
5
Rojas-Sánchez, Blanca, Hugo Castelán-Sánchez, Esmeralda Y. Garfias-Zamora, and Gustavo Santoyo. "Diversity of the Maize Root Endosphere and Rhizosphere Microbiomes Modulated by the Inoculation with Pseudomonas fluorescens UM270 in a Milpa System." Plants 13, no. 7 (March 26, 2024): 954. http://dx.doi.org/10.3390/plants13070954.
Abstract:
Milpa is an agroecological production system based on the polyculture of plant species, with corn featuring as a central component. Traditionally, the milpa system does not require the application of chemicals, and so pest attacks and poor growth in poor soils can have adverse effects on its production. Therefore, the application of bioinoculants could be a strategy for improving crop growth and health; however, the effect of external inoculant agents on the endemic microbiota associated with corn has not been extensively studied. Here, the objective of this work was to fertilize a maize crop under a milpa agrosystem with the PGPR Pseudomonas fluorescens UM270, evaluating its impact on the diversity of the rhizosphere (rhizobiome) and root endophytic (root endobiome) microbiomes of maize plants. The endobiome of maize roots was evaluated by 16S rRNA and internal transcribed spacer region (ITS) sequencing, and the rhizobiome was assessed by metagenomic sequencing upon inoculation with the strain UM270. The results showed that UM270 inoculation of the rhizosphere of P. fluorescens UM270 did not increase alpha diversity in either the monoculture or milpa, but it did alter the endophytic microbiome of maize plant roots by stimulating the presence of bacterial operational taxonomic units (OTUs) of the genera Burkholderia and Pseudomonas (in a monoculture), whereas, in the milpa system, the PGPR stimulated greater endophytic diversity and the presence of genera such as Burkholderia, Variovorax, and N-fixing rhizobia genera, including Rhizobium, Mesorhizobium, and Bradyrhizobium. No clear association was found between fungal diversity and the presence of strain UM270, but beneficial fungi, such as Rizophagus irregularis and Exophiala pisciphila, were detected in the Milpa system. In addition, network analysis revealed unique interactions with species such as Stenotrophomonas sp., Burkholderia xenovorans, and Sphingobium yanoikuyae, which could potentially play beneficial roles in the plant. Finally, the UM270 strain does not seem to have a strong impact on the microbial diversity of the rhizosphere, but it does have a strong impact on some functions, such as trehalose synthesis, ammonium assimilation, and polyamine metabolism. The inoculation of UM270 biofertilizer in maize plants modifies the rhizo- and endophytic microbiomes with a high potential for stimulating plant growth and health in agroecological crop models.
6
Jiao, Yin Shan, Yuan Hui Liu, Hui Yan, En Tao Wang, Chang Fu Tian, Wen Xin Chen, Bao Lin Guo, and Wen Feng Chen. "Rhizobial Diversity and Nodulation Characteristics of the Extremely Promiscuous Legume Sophora flavescens." Molecular Plant-Microbe Interactions® 28, no. 12 (December 2015): 1338–52. http://dx.doi.org/10.1094/mpmi-06-15-0141-r.
Abstract:
In present study, we report our extensive survey on the diversity and biogeography of rhizobia associated with Sophora flavescens, a sophocarpidine (matrine)-containing medicinal legume. We additionally investigated the cross nodulation, infection pattern, light and electron microscopies of root nodule sections of S. flavescens infected by various rhizobia. Seventeen genospecies of rhizobia belonging to five genera with seven types of symbiotic nodC genes were found to nodulate S. flavescens in natural soils. In the cross-nodulation tests, most representative rhizobia in class α-Proteobacteria, whose host plants belong to different cross-nodulation groups, form effective indeterminate nodules, while representative rhizobia in class β-Proteobacteria form ineffective nodules on S. flavescens. Highly host-specific biovars of Rhizobium leguminosarum (bv. trifolii and bv. viciae) and Rhizobium etli bv. phaseoli could establish symbioses with S. flavescens, providing further evidence that S. flavescens is an extremely promiscuous legume and it does not have strict selectivity on either the symbiotic genes or the species-determining housekeeping genes of rhizobia. Root-hair infection is found as the pattern that rhizobia have gained entry into the curled root hairs. Electron microscopies of ultra-thin sections of S. flavescens root nodules formed by different rhizobia show that the bacteroids are regular or irregular rod shape and nonswollen types. Some bacteroids contain poly-β-hydroxybutyrate (PHB), while others do not, indicating the synthesis of PHB in bacteroids is rhizobia-dependent. The extremely promiscuous symbiosis between S. flavescens and different rhizobia provide us a basis for future studies aimed at understanding the molecular interactions of rhizobia and legumes.
7
Fagorzi, Camilla, Alice Checcucci, George diCenzo, Klaudia Debiec-Andrzejewska, Lukasz Dziewit, Francesco Pini, and Alessio Mengoni. "Harnessing Rhizobia to Improve Heavy-Metal Phytoremediation by Legumes." Genes 9, no. 11 (November 8, 2018): 542. http://dx.doi.org/10.3390/genes9110542.
Abstract:
Rhizobia are bacteria that can form symbiotic associations with plants of the Fabaceae family, during which they reduce atmospheric di-nitrogen to ammonia. The symbiosis between rhizobia and leguminous plants is a fundamental contributor to nitrogen cycling in natural and agricultural ecosystems. Rhizobial microsymbionts are a major reason why legumes can colonize marginal lands and nitrogen-deficient soils. Several leguminous species have been found in metal-contaminated areas, and they often harbor metal-tolerant rhizobia. In recent years, there have been numerous efforts and discoveries related to the genetic determinants of metal resistance by rhizobia, and on the effectiveness of such rhizobia to increase the metal tolerance of host plants. Here, we review the main findings on the metal resistance of rhizobia: the physiological role, evolution, and genetic determinants, and the potential to use native and genetically-manipulated rhizobia as inoculants for legumes in phytoremediation practices.
8
Bernal, Gustavo, and Peter H. Graham. "Diversity in the rhizobia associated withPhaseolus vulgarisL. in Ecuador, and comparisons with Mexican bean rhizobia." Canadian Journal of Microbiology 47, no. 6 (June 1, 2001): 526–34. http://dx.doi.org/10.1139/w01-037.
Abstract:
Common beans (Phaseolus vulgaris L.) have centers of origin in both Mesoamerica and Andean South America, and have been domesticated in each region for perhaps 5000 years. A third major gene pool may exist in Ecuador and Northern Peru. The diversity of the rhizobia associated with beans has also been studied, but to date with an emphasis on the Mesoamerican center of origin. In this study we compared bean rhizobia from Mexico and Andean South America using both phenotypic and phylogenetic approaches. When differences between the rhizobia of these two regions were shown, we then examined the influence of bean cultivar on the most probable number (MPN) count and biodiversity of rhizobia recovered from different soils. Three clusters of bean rhizobia were distinguished using phenotypic analysis and principal-component analysis of Box A1R-PCR banding patterns. They corresponded principally to isolates from Mexico, and the northern and southern Andean regions, with isolates from southern Ecuador exhibiting significant genetic diversity. Rhizobia from Dalea spp., which are infective and effective on beans, may have contributed to the apparent diversity of rhizobia recovered from the Mesoamerican region, while the rhizobia of wild Phaseolus aborigineus from Argentina showed only limited similarity to the other bean rhizobia tested. Use of P. vulgaris cultivars from the Mesoamerican and Andean Phaseolus gene pools as trap hosts did not significantly affect MPN counts of bean rhizobia from the soils of each region, but did influence the diversity of the rhizobia recovered. Such differences in compatibility of host and Rhizobium could be a factor in the poor reputation for nodulation and N2fixation in this crop.Key words: Phaseolus vulgaris, Rhizobium diversity, Dalea spp., soil populations, specificity, centers of origin.
9
MAPFUMO, P., S. MPEPEREKI, and P. MAFONGOYA. "PIGEONPEA RHIZOBIA PREVALENCE AND CROP RESPONSE TO INOCULATION IN ZIMBABWEAN SMALLHOLDER-MANAGED SOILS." Experimental Agriculture 36, no. 4 (October 2000): 423–34. http://dx.doi.org/10.1017/s0014479700001009.
Abstract:
A study was conducted to determine the population sizes of indigenous pigeonpea (Cajanus cajan)-nodulating rhizobia and responses of the crop to rhizobial inoculation in soils under smallholder management. Rhizobia populations were determined in 21 soils from three different agro-ecological regions of Zimbabwe using the plant infection most-probable-number technique. Pigeonpea response to rhizobial inoculation was tested in five soils representative of low, medium and high rhizobia populations. Pigeonpea rhizobia ranged from undetectable to 121 cells per g soil compared with 16 to 159 cells per g soil for cowpea (Vigna unguiculata) which was used for reference. Soils with high cowpea rhizobia counts had relatively low counts of pigeonpea rhizobia and vice versa, showing that the two legumes associate with different subgroups of rhizobia. Poor soil organic matter, low soil moisture at sampling, low pH and low clay content of the soils had a significant negative effect on rhizobial counts. Organic matter appeared critical for maintenance of high populations of indigenous rhizobia in the mostly sandy soils sampled. Lack of pigeonpea response to inoculation in all the soils tested despite the low initial rhizobial populations could be the result of within-season proliferation of indigenous populations which are competitive and effective. There was evidence of rapid build-up of pigeonpea-compatible rhizobia within one growing season when the crop was first introduced. It was concluded that effective pigeonpea rhizobia occur in many arable soils of Zimbabwe. However, to fully exploit biological nitrogen fixation and maximize yields of pigeonpea, highly efficient, adapted and competitive indigenous rhizobial isolates must be identified and evaluated.
10
Abramova, A. V., and A. G. Topaj. "Case Study of Plant-Microbial Symbiosis Model Using Evolutionary Game Theory." Mathematical Biology and Bioinformatics 13, no. 1 (May 8, 2018): 130–58. http://dx.doi.org/10.17537/2018.13.130.
Abstract:
Nitrogen-fixing bacteria (rhizobia) have symbiotic relationships with legumes: they inhabit legume root nodules and convert atmospheric nitrogen to a plant available form in exchange for photosynthates. Generally, this symbiotic process called biological nitrogen fixation is mutually beneficial to both plants and bacteria. Using this mechanism symbionts acquire alternative sources of hard-to-reach individual growth resources (carbon for rhizobia and nitrogen for plants). However, not all rhizobia provide fixed nitrogen to the host plant honestly: some of them can behave as a kind of cheaters. Unlimited cheating rhizobia strains propagation may potentially disrupt the symbiotic relationships. This raises the question of plant–rhizobia mutualism evolutionary stability. This paper presents the results of the legume–rhizobia interactions investigation implemented as AnyLogic agent-based models. Three modifications of interaction model ("one plant – one strain of rhizobia", "one plant – several strains of rhizobia", "one plant with root nitrogen uptake – several strains of rhizobia") in the form of evolutionary games in two populations (rhizobia and plants) are considered by the authors. Simulated natural selection is driven by populations heterogeneity: each agent has its own cooperation parameter which determines its strategy in evolutionary game. In the set of numerical experiments the following results were obtained. Simulated populations tend to become homogeneous with cooperation parameter value close to the theoretically optimal. Such degenerated structure of populations is evolutionarily stable and maximizes the total growth of the entire symbiotic system. Thus, the logic of symbionts co-development simulation itself prevents the emergence of parasitic strategies and automatically provides rational and mutually beneficial partnership sustainability. This remains true in the early stages of ontogenesis or under the assumption that life cycle duration is unlimited.
11
Provorov, Nikolay A., I. G. Fokina, Marina L. Roumiantseva, and Boris V. Simarov. "Transfer of Sym-plasmids into symbiotically active and asymbiotic rhizobia strains: properties of recombinants and possible evolutionary consequences." Ecological genetics 2, no. 2 (June 15, 2004): 29–34. http://dx.doi.org/10.17816/ecogen2229-34.
Abstract:
Transfer of Sym-plasmids from the clover rhizobia to avirulent mutants of the same rhizobia species or of alfalfa rhizobia resulted in recombinants with a restored symbiotic activity. Transfer of these plasmids into the wild type isogenic strains lead to a decrease of their symbiotic activity. These data confirm the hypothesis on the crucial role of avirulent rhizobia strains in the transfer of Sym-plasmids which directs evolution of these bacteria
12
Downie, J. Allan. "A Nod of recognition: How the ups and downs of Ca2+ lead to nodule development during the initiation of rhizobial-legume symbioses." Biochemist 36, no. 2 (April 1, 2014): 4–7. http://dx.doi.org/10.1042/bio03602004.
Abstract:
One of the most sensitive Ca2+-signalling pathways identified in nature is that which is activated by rhizobia during the initiation of symbiotic nitrogen-fixing nodules on legume roots. Leguminous plants owe much of their ecological success to their symbiosis with rhizobia, because rhizobia provide NH3 to plants by reducing N2 within specialized root organs called nodules. Rhizobia induce nodule development by activating a plant signalling pathway that requires oscillations of Ca2+ within the nucleus.
13
Santillana Villanueva, Nery. "Mecanismos de inducción de rizobios para reducir el estrés por sequía en las leguminosas." Revista de Investigaciones Altoandinas - Journal of High Andean Research 23, no. 4 (October 31, 2021): 258–65. http://dx.doi.org/10.18271/ria.2021.263.
Abstract:
Drought is one of the main limitations of agricultural productivity and food security, in Andean mountain. The use of atmospheric nitrogen-fixing rhizobia in symbiosis with legumes, and tolerant to a wide range of adverse conditions, such as drought, is a great potential in sustainable agriculture. The aim of this review is to compile studies about drought stress effect on the legume-rhizobia symbiosis and rhizobia mechanisms to induce drought tolerance in legumes. The search for information was conducted from August to December 2020, using key terms. The drought effect on the nodulation and atmospheric nitrogen fixation process is made known, as well as the rhizobia ability to synthesize exopolysaccharides, enzymes, phytohormones, siderophores, osmolytes and solubilize phosphates as induction mechanisms to mitigate drought stress in legumes. This review will serve to propose future research using rhizobia to mitigate the drought effect on the legumes cultivation in environments such as the Andean mountains.
14
Zakhia, Fr�d�ric, and Philippe de Lajudie. "Taxonomy of rhizobia." Agronomie 21, no. 6-7 (September 2001): 569–76. http://dx.doi.org/10.1051/agro:2001146.
15
Denton, M. D., D. R. Coventry, P. J. Murphy, J. G. Howieson, and W. D. Bellotti. "Competition between inoculant and naturalised Rhizobium leguminosarum bv. trifolii for nodulation of annual clovers in alkaline soils." Australian Journal of Agricultural Research 53, no. 9 (2002): 1019. http://dx.doi.org/10.1071/ar01138.
Abstract:
Inoculant rhizobia typically need to compete with naturalised soil populations of rhizobia to form legume nodules. We have used the polymerase chain reaction to test the ability of seed-inoculated rhizobia to compete with naturalised populations of rhizobia and form nodules on clover (Trifolium alexandrinum, T.�purpureum, and T. resupinatum) in alkaline soil. Clover rhizobia, Rhizobium leguminosarum bv. trifolii, were identified at the strain level using either a nif-specific RP01 primer or ERIC primers. Analysis of rhizobia isolated from nodules indicated that strain TA1 competed poorly for nodule occupancy at 2 field sites (Roseworthy and Mallala, South Australia), with the exception that it nodulated T. alexandrinum at a level of 39% at the Roseworthy site in the first year of the trial. Strains CC2483g and WSM409 successfully colonised nodules when inoculated onto a particular clover species (T. resupinatum and T. purpureum, respectively) in the first year of inoculation and persisted in the soil to form nodules in the following year. Nodules frequently contained naturalised strains of rhizobia, distinct from introduced commercial strains. Dominant isolates were specific to a field site and nodulated all 3 clover species in both years of the field trial, with each isolate occupying up to 19% of the total nodules at a field site. It was hypothesised that field isolates had a better alkaline soil tolerance conferring a greater ability to nodulate clovers under these edaphic conditions. The results indicate that soil populations of rhizobia may provide a significant constraint to the introduction of current Australian commercial clover rhizobia into alkaline soils, and a more profitable strategy may be to seek rhizobial inoculants that are adapted to these soils.
16
Harsono, A., D. Sucahyono, E. Pratiwi, A. Sarjia, H. Pratiwi, D. Andreas, and T. Simarmata. "The effectiveness of technology packages of 15 biofertilizer formulas to increase soybean productivity on acidic soils." IOP Conference Series: Earth and Environmental Science 911, no. 1 (November 1, 2021): 012041. http://dx.doi.org/10.1088/1755-1315/911/1/012041.
Abstract:
Abstract The potentcy of acidic soils for soybean development in Indonesia is quite large. However low of soil fertility and microorganisms population become contrains for achieving high productifity of soybean. The aim of this research is to determine the effectiveness of technology packages for 15 biofertilizers formula to increase soybean productivity in acidic soils. The research was conducted during the end of rainy season in South Kalimantan. The soil use in the study had pH 5.2 and soil Al-saturation 34.2%. The reasearch was arranged in a randomized block design, three replications consisted of 20 treatmens, namely: 1) 0 NPK, 2) 50% NPK, 3) 50% NPK +2 t/ha organic fertilizer 4) 70% NPK, 5) 100% NPK (100 kg urea + 100 kg SP36 + 100 kg KCl/ha), 6) Iletrisoy+ Biovam+Starmix, 7) Iletrosoy Plus, 8) Beyonic, 9 Biotrico, 10) Probio New, 11) RhizoBIOST, 12) Bio-SRF, 13) Biopim, 14) BioMIGE, 15) Biocoat, 16) FajarSOYA, 17) Rhizobion, 18) Agrizone, 19) Rhizoplus, and 20) BISRF. For each biological fertilizer, 50-75% of recommended NPK fertilizers were given at 15 days after planting. The results indicated that combination of Biovam + Iletrisoy + Startmix biofertilizers, Iletrisoy plus, Biotricho, Probio New, Bio Mige, and Fajar SOYA were effective for increasing soybean productivity on acidic soils. These biological fertilizers + 50% recommended NPK + 1.5 t/ha organic fertilizer increases pods number, and soybean productivity more than 10% compared to the recommended NPK fertilizer dosage whic was 1.81 t/ha. Several of these biological fertilizers have good prospects to be developed as bio-fertilizers for soybeans in acidic soils.
17
SEKKOUR, Sonia, Nadjia Benhamed, and Abdelkader Bekki. "The field inoculation of Acacia saligna with efficient rhizobia strains for sand quarry restoration in Algeria." South Asian Journal of Experimental Biology 12, no. 5 (September 19, 2022): 599–608. http://dx.doi.org/10.38150/sajeb.12(5).p599-608.
Abstract:
Sand quarries constituting very specific environments where native plants and surface soil are destroyed. The resulting substrates are practically sterile from an organic and biological point of view due to the absence of humus, microfauna and flora. planting legumes like Acacia saligna inoculated with his microbial partner rhizobia is strategic key to enhance the substrate fertility and lead to an ecological restoration of sandpits. Here we have selected the most efficient couple A. saligna-rhizobia with the goal to rehabilitate Sidi Lakhdar sandpit in the end of exploitation and to follow the filed persistence of introduced rhizobia into A. saligna nodules. The in vitro efficiency test permitted the selection of three inocula which performed differently once transferred onto natural soil and in the field. The ASB13 (Ensifer sp.) were found to be better inoculum for sandpit rehabilitation and A. saligna-rhizobia couple introduction for above and underground degraded sites. The introduced rhizobia didn’t persist in nodules of A. saligna in different treated blocks which were revealed by the PCR-RFLP profiles after the digestion by restriction enzyme HaeIII. These results support the literature data on failure/success of inoculants pertain to the persistence of rhizobia (inoculants) in soil, inoculant success is affected not only by environmental conditions such as temperature, pH, salinity but also by competitivity of indigenous rhizobia. We conclude that the rhizobia-based inocula selection for field application necessitates testing selected strains under the environmental conditions prevailing in the site intended to be rehabilitated.
18
Hamilton, Leo J., Kevin F. M. Reed, Elainne M. A. Leach, and John Brockwell. "Boron deficiency in pasture based on subterranean clover (Trifolium subterraneum L.) is linked to symbiotic malfunction." Crop and Pasture Science 66, no. 11 (2015): 1197. http://dx.doi.org/10.1071/cp14300.
Abstract:
Field and glasshouse experiments confirmed the occurrence of boron (B) deficiency in subterranean clover (Trifolium subterraneum L.) pasture in eastern Victoria. Diminished productivity was linked to the small-seededness of clover and the poor effectiveness of clover root-nodule bacteria (rhizobia, Rhizobium leguminosarum bv. trifolii). Productivity, especially of clover and clover seed, increased following applications of up to 6 kg B ha–1 (P < 0.001). The response was delayed, occurring several years after the initial application of B, unless the land was resown with fresh clover seed inoculated with an effective strain of rhizobia. B deficiency in the nodulated legume induced conditions within the plant and or its rhizobia that led to impaired nitrogen (N2) fixation. Glasshouse research indicated that populations of soil-borne rhizobia taken from B-deficient soils were poorly effective in N2 fixation and that rhizobia from soils growing subterranean clover cv. Leura were significantly less effective (P < 0.05) than rhizobia from a soil growing cv. Mt Barker. Additionally, subterranean clover seed generated in B-deficient soils was at least one-third smaller than the seed of commercial seed but responded to inoculation with effective rhizobia. This indicated that any symbiotic malfunction of clover from B-deficient soils was not due to an inability to respond to nitrogen per se. On the other hand, cv. Leura from B-deficient soils fixed significantly less N2 than commercial cv. Leura when each was inoculated with rhizobia from B-deficient soils.
19
Drew, E. A., M. D. Denton, V. O. Sadras, and R. A. Ballard. "Agronomic and environmental drivers of population size and symbiotic performance of Rhizobium leguminosarum bv. viciae in Mediterranean-type environments." Crop and Pasture Science 63, no. 5 (2012): 467. http://dx.doi.org/10.1071/cp12032.
Abstract:
The population size and symbiotic performance (ability to fix N2) of rhizobia (Rhizobium leguminosarum bv. viciae) capable of nodulating field pea (Pisum sativum) were assessed in 114 soils from Mediterranean-type environments of southern Australia. All soils were collected in autumn, before the growing season, and had a history of crop legumes including field pea, faba bean, lentil, or vetch. The most probable number (MPN) technique, with vetch as a trap plant, was used to estimate the numbers of pea rhizobia in soils. Of the soils tested, 29% had low numbers of pea rhizobia (<100 rhizobia/g), 38% had moderate numbers (100–1000/g), and the remaining 33% had >1000/g. Soil pH, the frequency of a host crop in the rotation, and the number of summer days with a maximum temperature >35°C were strongly correlated with the pea rhizobia population size. Symbiotic performance (SP) of pea rhizobia in soils was assessed for soils with a MPN >100 rhizobia/g. An extract of the soils was used to inoculate two field pea cultivars growing in a nitrogen-deficient potting media in the greenhouse. Plants were grown for 5 weeks after inoculation and shoot dry matter was expressed as a percentage of the dry matter of plants grown with a commercial strain R. leguminosarum bv. viciae, SU303. Symbiotic performance ranged from 25 to 125%. One-quarter of the soils assessed had suboptimal SP (i.e. <70%). Soil and climatic variables were weakly associated with SP, with pH and average annual rainfall accounting for 17% of the variance. This research highlights the complexity of factors influencing population size and symbiotic performance of pea rhizobia in soils. Options for the improved management of populations of pea rhizobia in Mediterranean environments are discussed. Specifically, our data indicate that inoculation of pea crops is likely to be beneficial where pH(H2O) <6.6, particularly when summers have been hot and dry and when a host has been absent for ≥5 years, as numbers of rhizobia are likely to be below the thresholds needed to optimise nodulation and crop growth. New inoculation technologies and plant breeding will be required to overcome large populations of pea rhizobia with suboptimal SP.
20
Ballard, R. A., B. R. Shepherd, and N. Charman. "Nodulation and growth of pasture legumes with naturalised soil rhizobia. 3. Lucerne (Medicago sativa L.)." Australian Journal of Experimental Agriculture 43, no. 2 (2003): 135. http://dx.doi.org/10.1071/ea02047.
Abstract:
An assessment was made of the ability of 2 genetically diverse cultivars of lucerne (Trifecta and Sceptre) to nodulate and form effective symbioses with the strains of Sinorhizobium meliloti naturalised in 50 soils. Soils were collected from 42 dryland lucerne pastures and 8 irrigated multiple-use lucerne stands in the south-east of South Australia. The density of lucerne in the paddock, age of the lucerne stand and rhizobial inoculation practice were recorded at sampling. The lucerne swards were on average 5.6 years old (range 1–28) and had a mean plant density of 25 plants/m2 (range 3–66). The lucerne in 39 of the paddocks had been inoculated with rhizobia at sowing.The most probable number of rhizobia (S. meliloti) able to nodulate lucerne was determined for each soil. The most probable number of lucerne rhizobia exceeded 1.0 × 103/g in 23 of the soils. The most probable number of rhizobia in the soil was significantly correlated (r = 0.64) with soil pH. All 13 soils that contained less than 1.0�×�102�rhizobia/g had a pH of less than 6.3.The effectiveness at nitrogen fixation of each population of soil rhizobia was determined in a glasshouse experiment. There was no significant interaction between lucerne cultivar and soil inoculant. Generally, the soil rhizobia were highly effective, with 35 of the 50 soil inoculants producing more than 70% of the shoot dry weight associated with an effective inoculant strain (WSM826). Decreased lucerne shoot dry weights resulting from the remaining soil inoculants were associated with a lower most probable number of rhizobia in the soil, rather than poor symbiotic effectiveness of those rhizobia. This study highlighted the ability of both Trifecta and Sceptre lucernes to form an effective symbiosis with the rhizobia that have naturalised in the soils across a 25 000 km2 region of South Australia. It also showed that soil acidity is detrimental to rhizobial survival even in a perennial legume system and suggests that rhizobia that persist and form nodules in acidic soils should be a focus in the selection of new inoculant strains for lucerne.
21
Orozco-Mosqueda, Ma del Carmen, Ajay Kumar, Olubukola Oluranti Babalola, and Gustavo Santoyo. "Rhizobiome Transplantation: A Novel Strategy beyond Single-Strain/Consortium Inoculation for Crop Improvement." Plants 12, no. 18 (September 11, 2023): 3226. http://dx.doi.org/10.3390/plants12183226.
Abstract:
The growing human population has a greater demand for food; however, the care and preservation of nature as well as its resources must be considered when fulfilling this demand. An alternative employed in recent decades is the use and application of microbial inoculants, either individually or in consortium. The transplantation of rhizospheric microbiomes (rhizobiome) recently emerged as an additional proposal to protect crops from pathogens. In this review, rhizobiome transplantation was analyzed as an ecological alternative for increasing plant protection and crop production. The differences between single-strain/species inoculation and dual or consortium application were compared. Furthermore, the feasibility of the transplantation of other associated micro-communities, including phyllosphere and endosphere microbiomes, were evaluated. The current and future challenges surrounding rhizobiome transplantation were additionally discussed. In conclusion, rhizobiome transplantation emerges as an attractive alternative that goes beyond single/group inoculation of microbial agents; however, there is still a long way ahead before it can be applied in large-scale agriculture.
22
McInnes, A., and R. A. Date. "Improving the survival of rhizobia on Desmanthus and Stylosanthes seed at high temperature." Australian Journal of Experimental Agriculture 45, no. 3 (2005): 171. http://dx.doi.org/10.1071/ea03152.
Abstract:
In response to observed inoculation failures in the tropical forage legumes Desmanthus spp. and Stylosanthes seabrana, research was initiated to improve the survival of rhizobia on seed at high temperature. We compared the survival of rhizobia in freeze-dried and conventional peat inoculants in the laboratory at 30–50°C and 5–8% relative humidity. Higher numbers of rhizobia [>106 colony forming units (cfu)/seed] were counted on seed inoculated with freeze-dried rhizobia compared with seed inoculated with peat (≤104) in all treatments at all sampling times (0, 2, 7, 14 and 21 days after inoculation). Increasing the incubation temperature to 70°C significantly (P<0.05) reduced the number of freeze-dried rhizobia surviving on seed, but rhizobia were detectable on Desmanthus seed 1, 2 and 7 days after inoculation and on Stylosanthes seed 1 and 2 days after inoculation. Freeze-dried rhizobia stored over silica gel in the laboratory for 325–349 days lost 3.5–4.5 log10 cfu/g. Freeze-dried rhizobia inoculated on seed and stored in a farm shed from April to July lost 0.6–0.8 log10 cfu/seed.month. Survival of rhizobia in peat and freeze-dried inoculants on seed over 1–4 weeks in a glasshouse without air conditioning (18–51°C) was poor (0–1.2 log10 cfu/seed at all sampling times), and was attributed to exposure to a combination of high temperature and ambient relative humidity. Laboratory studies confirmed that increasing relative humidity from 5–8 to 31–63% reduced the survival of rhizobia in freeze-dried inoculants on seed, particularly at 50°C. Further work is required to improve the survival of freeze-dried inoculants at a relative humidity greater than 5–8% and under long-term storage. Optimisation of this technology has the potential to increase inoculation success for all legumes sown at high temperature in Australia. Freeze-dried inoculant technology may also have an application in seed preinoculation.
23
Artigas Ramírez, María D., Jéssica D. Silva, Naoko Ohkama-Ohtsu, and Tadashi Yokoyama. "In vitro rhizobia response and symbiosis process under aluminum stress." Canadian Journal of Microbiology 64, no. 8 (August 2018): 511–26. http://dx.doi.org/10.1139/cjm-2018-0019.
Abstract:
Aluminum (Al) toxicity is a major problem affecting soil fertility, microbial diversity, and nutrient uptake of plants. Rhizobia response and legume interaction under Al conditions are still unknown; it is important to understand how to develop and improve legume cultivation under Al stress. In this study, rhizobia response was recorded under different Al concentrations. Al effect on rhizobial cells was characterized by combination with different two pH conditions. Symbiosis process was compared between α- and β-rhizobia inoculated onto soybean varieties. Rhizobial cell numbers was decreased as Al concentration increased. However, induced Al tolerance considerably depended on rhizobia types and their origins. Accordingly, organic acid results were in correlation with growth rate and cell density which suggested that citric acid might be a positive selective force for Al tolerance and plant interaction on rhizobia. Al toxicity delayed and interrupted the plant–rhizobia interaction and the effect was more pronounced under acidic conditions. Burkholderia fungorum VTr35 significantly improved plant growth under acid–Al stress in combination with all soybean varieties. Moreover, plant genotype was an important factor to establish an effective nodulation and nitrogen fixation under Al stress. Additionally, tolerant rhizobia could be applied as an inoculant on stressful agroecosystems. Furthermore, metabolic pathways have still been unknown under Al stress.
24
Šenberga, Alise, Laila Dubova, Ina Alsiņa, and Liene Strauta. "Rhizobium sp. – a Potential Tool for Improving Protein Content in Peas and Faba Beans." Rural Sustainability Research 37, no. 332 (July 1, 2017): 2–9. http://dx.doi.org/10.1515/plua-2017-0001.
Abstract:
AbstractLegume seed inoculation prior to sowing is a well-known practice in agriculture. Nitrogen fixation, due to the symbiotic relationship between legumes and rhizobia, improves the productivity of legumes. Rhizobia strain specificity can be observed very often, leading to differences in the total protein content. In this study two faba bean cultivars (‘Karmazyn’ and ‘Bartek’) and five pea cultivars (‘Retrija’, ‘Zaiga’, ‘Lāsma’, ‘Vitra’ and ‘Bartek’) were tested using various rhizobia strains. In addition, strain effectivity was observed in four different soil types. Overall, the protein content increase was observed after seed inoculation withRhizobium sp. Rhizobia strain and plant cultivar interaction specification was observed. Plant cultivar appeared to have a decisive role in the formation of protein content when inoculated withRhizobium sp.From these pilot experiments, it can be concluded that, when choosingRhizobium sp.strains for legume inoculation, soil type also should be considered. Rhizobia has the potential to be used as a commercial preparation intended for increasing legume protein content, alongside with increased legume yield; however, different rhizobia strains should be mixed together to achieve the optimal result.
25
Stout, D. G., J. W. Hall, B. M. Brooke, G. Baalim, and D. J. Thompson. "Effect of storage temperature and time on viability of rhizobia on lime-coated alsike clover (Trifolium hybridum) seed." Journal of Agricultural Science 120, no. 2 (April 1993): 205–11. http://dx.doi.org/10.1017/s0021859600074244.
Abstract:
SUMMARYSeed is often stored in warehouses where the temperature may drop below freezing or increase to 40°C depending on the time of year. Survival of rhizobia on lime-coated alsike clover (Trifolium hybridumL.) seed stored in polypropylene bags was monitored under various temperature regimes ranging from –10 to 35 °C at Agriculture Canada Range Research Station, Kamloops, British Columbia, Canada during 1990 and 1991. Rhizobia were applied ata range of initial concentrations. Seed was inoculated with a peat-based clover inoculant (‘B’ inoculant, Nitragin Ltd, Milwaukee, Wisconsin, USA), and then given a commercial polymer-based lime coat (GNR™, Grow Tec Ltd, Nisku, Alberta, Canada). Rhizobia died continuously at all temperatures within the range —10 to 35°C. The dependence of Iog10(number of viable rhizobia/seed) on storage time was best described by a linear equation: Iog10(viable rhizobia/seed) =a+b(time). Coefficientaprovidedan estimate of the initial concentration of rhizobia. Coefficientbprovided a measure of how rapidly rhizobia died. The death rate of rhizobia was the same during storage at 5 or 20 °C, but increased at a storage temperature of 35 °C. Storage at freezing temperatures did not increase the rate of rhizobial death but repeated freezing and thawing resulted in an increase. As the rate of rhizobial death was similar at constant temperatures from — 10 to 20 °C, temperature requirements are not stringent. Nevertheless, some temperature control is required to maximize the legal storage life of preinoculated coated seed, which in this study was estimated to be 96 days.
26
Ma, Wenbo, Donna M. Penrose, and Bernard R. Glick. "Strategies used by rhizobia to lower plant ethylene levels and increase nodulation." Canadian Journal of Microbiology 48, no. 11 (November 1, 2002): 947–54. http://dx.doi.org/10.1139/w02-100.
Abstract:
Agriculture depends heavily on biologically fixed nitrogen from the symbiotic association between rhizobia and plants. Molecular nitrogen is fixed by differentiated forms of rhizobia in nodules located on plant roots. The phytohormone, ethylene, acts as a negative factor in the nodulation process. Recent discoveries suggest several strategies used by rhizobia to reduce the amount of ethylene synthesized by their legume symbionts, decreasing the negative effect of ethylene on nodulation. At least one strain of rhizobia produces rhizobitoxine, an inhibitor of ethylene synthesis. Active 1-aminocyclopropane-1-carboxylate (ACC) deaminase has been detected in a number of other rhizobial strains. This enzyme catalyzes the cleavage of ACC to α-ketobutyrate and ammonia. It has been shown that the inhibitory effect of ethylene on plant root elongation can be reduced by the activity of ACC deaminase.Key words: rhizobia, nodulation, ethylene, ACC deaminase, rhizobitoxine.
27
De Meyer, Sofie E., Leah Briscoe, Pilar Martínez-Hidalgo, Christina M. Agapakis, Paulina Estrada de-los Santos, Rekha Seshadri, Wayne Reeve, et al. "Symbiotic Burkholderia Species Show Diverse Arrangements of nif/fix and nod Genes and Lack Typical High-Affinity Cytochrome cbb3 Oxidase Genes." Molecular Plant-Microbe Interactions® 29, no. 8 (August 2016): 609–19. http://dx.doi.org/10.1094/mpmi-05-16-0091-r.
Abstract:
Genome analysis of fourteen mimosoid and four papilionoid beta-rhizobia together with fourteen reference alpha-rhizobia for both nodulation (nod) and nitrogen-fixing (nif/fix) genes has shown phylogenetic congruence between 16S rRNA/MLSA (combined 16S rRNA gene sequencing and multilocus sequence analysis) and nif/fix genes, indicating a free-living diazotrophic ancestry of the beta-rhizobia. However, deeper genomic analysis revealed a complex symbiosis acquisition history in the beta-rhizobia that clearly separates the mimosoid and papilionoid nodulating groups. Mimosoid-nodulating beta-rhizobia have nod genes tightly clustered in the nodBCIJHASU operon, whereas papilionoid-nodulating Burkholderia have nodUSDABC and nodIJ genes, although their arrangement is not canonical because the nod genes are subdivided by the insertion of nif and other genes. Furthermore, the papilionoid Burkholderia spp. contain duplications of several nod and nif genes. The Burkholderia nifHDKEN and fixABC genes are very closely related to those found in free-living diazotrophs. In contrast, nifA is highly divergent between both groups, but the papilionoid species nifA is more similar to alpha-rhizobia nifA than to other groups. Surprisingly, for all Burkholderia, the fixNOQP and fixGHIS genes required for cbb3 cytochrome oxidase production and assembly are missing. In contrast, symbiotic Cupriavidus strains have fixNOQPGHIS genes, revealing a divergence in the evolution of two distinct electron transport chains required for nitrogen fixation within the beta-rhizobia.
28
Ballard, R. A., A. D. Craig, and N. Charman. "Nodulation and growth of pasture legumes with naturalised soil rhizobia.2. Balansa clover (Trifolium michelianum Savi)." Australian Journal of Experimental Agriculture 42, no. 7 (2002): 939. http://dx.doi.org/10.1071/ea01092.
Abstract:
Balansa clover (Trifolium michelianum Savi) is grown widely across southern and eastern Australia. The presence of suitable rhizobia (Rhizobium leguminosarum bv. trifolii) for this species of clover, and their ability to form an effective symbiosis, was assessed in a survey of 43 soils collected from across Australia. The effectiveness of the soil rhizobia is compared with that of strains WU95 and WSM409. The study confirmed the widespread occurrence of clover rhizobia in Australian soils. No clover rhizobia were detected in 6 of the 43 soils and this was probably associated with a history of clover absence at these soil locations. Thirty of the soils contained more than 500 rhizobia per gram. These rhizobia varied from highly effective for soil T2 (128% of WSM409) through to ineffective for soil V9 (22% of WSM409). Few soil inoculants were more effective than strain WSM409. Commercial inoculant strain WSM409 was generally more effective than former inoculant strain WU95.The suboptimal performance of the rhizobia in many of the soils indicates that there is an opportunity to improve the level of nitrogen fixation by balansa clover in the field. Bearing in mind the difficulties associated with the introduction and persistence of applied inoculant strains, cultivar selection is considered as an approach to improve the symbiosis. However, this study indicated little variation in the performance of the 3 commercial cultivars, Frontier, Paradana and Bolta, in this regard.
29
Zhang, Nina, Li Wang, Juan Chen, and Zhouping Shangguan. "H2S Crosstalk in Rhizobia Modulates Essential Nutrient Allocation and Transport in Soybean." Agronomy 13, no. 5 (May 10, 2023): 1332. http://dx.doi.org/10.3390/agronomy13051332.
Abstract:
Hydrogen sulfide (H2S), a novel gas signaling molecule, plays a crucial role in plant growth and stress response. However, little attention has been devoted to the regulation of H2S on nutrient transport and utilization in legume–rhizobia symbiosis systems. Although we have previously proven that H2S synergized with rhizobia to considerably enhance nitrogen (N) metabolism and remobilization in N-deficient soybeans, it remains uncertain if changes in nutrient absorption, metabolism, and accumulation occur concurrently. Therefore, employing a synergistic treatment of H2S and rhizobia, we examined the dry matter biomass and carbon (C), N, phosphorous (P), and potassium (K) nutrient content in various organs of soybean from blooming to maturity. Firstly, H2S and rhizobia application obviously improved leaf and plant phenotypes and biomass accumulation in different organs during N-deficient soybean development. Second, from flowering to maturity, the contents and stoichiometric ratios of C, N, P, and K in various organs of soybean were changed to variable degrees by H2S and rhizobia. Furthermore, H2S collaborated with rhizobia to significantly affect grain nutrient harvest across soybean growth as well as overall plant nutrient accumulation. Consequently, H2S synergizes with rhizobia to optimize grain harvest quality and nutrient accumulation across the plant by managing the rational allocation and dynamic balance of nutrients in diverse organs, hence boosting soybean development and production.
30
Prévost, Danielle, Pascal Drouin, Serge Laberge, Annick Bertrand, Jean Cloutier, and Gabriel Lévesque. "Cold-adapted rhizobia for nitrogen fixation in temperate regions." Canadian Journal of Botany 81, no. 12 (December 1, 2003): 1153–61. http://dx.doi.org/10.1139/b03-113.
Abstract:
Rhizobia from Canadian soils were selected for cold adaptation with the aim of improving productivity of legumes that are subjected to cool temperatures during the growing season. One approach was to use rhizobia associated with legume species indigenous to arctic and subarctic regions: (i) Mesorhizobium sp. isolated from Astragalus and Oxytropis spp. and (ii) Rhizobium leguminosarum from Lathryrus spp. The majority of these rhizobia are considered psychrotrophs because they can grow at 0 °C. The advantages of cold adaptation of arctic Mesorhizobium to improve legume symbiosis were demonstrated with the temperate forage legume sainfoin (Onobrychis viciifolia). In laboratory and field studies, arctic rhizobia were more efficient than temperate (commercial) rhizobia in improving growth of sainfoin and were more competitive in forming nodules. Biochemical studies on cold adaptation showed higher synthesis of cold shock proteins in cold-adapted than in nonadapted arctic rhizobia. Since arctic Mesorhizobium cannot nodulate agronomically important legumes, the nodulation genes and the bacterial signals (Nod factors) were characterized as a first step to modifying the host specificity of nodulation. Another valuable approach was to screen for cold adaptation, that is, rhizobia naturally associated with agronomic legumes cultivated in temperate areas. A superior strain of Sinorhizobium meliloti adapted for nodulation of alfalfa at low temperatures was selected and was the most efficient for improving growth of alfalfa in laboratory and field studies. This strain also performed well in improving regrowth of alfalfa after overwintering under cold and anaerobic (ice encasement) stresses, indicating a possible cross-adaptation of selected rhizobia for various abiotic stresses inherent to temperate climates.Key words: cold adaptation, legumes, symbiotic efficiency, cold shock protein, nodulation genes, anaerobiosis.
31
Chakrabarti, S. K., A. K. Mishra, and P. K. Chakrabartty. "DNA homology studies of rhizobia from Cicer arietinum L." Canadian Journal of Microbiology 32, no. 6 (June 1, 1986): 524–27. http://dx.doi.org/10.1139/m86-096.
Abstract:
The taxonomic status of rhizobia which infect Cicer arietinum is poorly defined. Historically these organisms have been placed under Rhizobium leguminosarum; however, later reports suggested that they be treated as a separate cross-inoculation group. Therefore, DNA homology tests were carried out with various rhizobia. The data indicate that rhizobia from Cicer cannot be placed under any of the recognised species of Rhizobium.
32
Quides, Kenjiro W., Alexandra J. Weisberg, Jerry Trinh, Fathi Salaheldine, Paola Cardenas, Hsu-Han Lee, Ruchi Jariwala, Jeff H. Chang, and Joel L. Sachs. "Experimental evolution can enhance benefits of rhizobia to novel legume hosts." Proceedings of the Royal Society B: Biological Sciences 288, no. 1951 (May 26, 2021): 20210812. http://dx.doi.org/10.1098/rspb.2021.0812.
Abstract:
Legumes preferentially associate with and reward beneficial rhizobia in root nodules, but the processes by which rhizobia evolve to provide benefits to novel hosts remain poorly understood. Using cycles of in planta and in vitro evolution, we experimentally simulated lifestyles where rhizobia repeatedly interact with novel plant genotypes with which they initially provide negligible benefits. Using a full-factorial replicated design, we independently evolved two rhizobia strains in associations with each of two Lotus japonicus genotypes that vary in regulation of nodule formation. We evaluated phenotypic evolution of rhizobia by quantifying fitness, growth effects and histological features on hosts, and molecular evolution via genome resequencing. Rhizobia evolved enhanced host benefits and caused changes in nodule development in one of the four host–symbiont combinations, that appeared to be driven by reduced costs during symbiosis, rather than increased nitrogen fixation. Descendant populations included genetic changes that could alter rhizobial infection or proliferation in host tissues, but lack of evidence for fixation of these mutations weakens the results. Evolution of enhanced rhizobial benefits occurred only in a subset of experiments, suggesting a role for host–symbiont genotype interactions in mediating the evolution of enhanced benefits from symbionts.
33
Taulé, Cecilia, María Zabaleta, Cintia Mareque, Raúl Platero, Lucía Sanjurjo, Margarita Sicardi, Lillian Frioni, Federico Battistoni, and Elena Fabiano. "New Betaproteobacterial Rhizobium Strains Able To Efficiently Nodulate Parapiptadenia rigida (Benth.) Brenan." Applied and Environmental Microbiology 78, no. 6 (January 6, 2012): 1692–700. http://dx.doi.org/10.1128/aem.06215-11.
Abstract:
ABSTRACTAmong the leguminous trees native to Uruguay,Parapiptadenia rigida(Angico), a Mimosoideae legume, is one of the most promising species for agroforestry. Like many other legumes, it is able to establish symbiotic associations with rhizobia and belongs to the group known as nitrogen-fixing trees, which are major components of agroforestry systems. Information about rhizobial symbionts for this genus is scarce, and thus, the aim of this work was to identify and characterize rhizobia associated withP. rigida. A collection of Angico-nodulating isolates was obtained, and 47 isolates were selected for genetic studies. According to enterobacterial repetitive intergenic consensus PCR patterns and restriction fragment length polymorphism analysis of theirnifHand 16S rRNA genes, the isolates could be grouped into seven genotypes, including the generaBurkholderia,Cupriavidus, andRhizobium, among which theBurkholderiagenotypes were the predominant group. Phylogenetic studies ofnifH,nodA, andnodCsequences from theBurkholderiaand theCupriavidusisolates indicated a close relationship of these genes with those from betaproteobacterial rhizobia (beta-rhizobia) rather than from alphaproteobacterial rhizobia (alpha-rhizobia). In addition, nodulation assays with representative isolates showed that while theCupriavidusisolates were able to effectively nodulateMimosa pudica, theBurkholderiaisolates produced white and ineffective nodules on this host.
34
Ding, Hao, and Michael F. Hynes. "Plasmid transfer systems in the rhizobia." Canadian Journal of Microbiology 55, no. 8 (August 2009): 917–27. http://dx.doi.org/10.1139/w09-056.
Abstract:
Rhizobia are agriculturally important bacteria that can form nitrogen-fixing nodules on the roots of leguminous plants. Agricultural application of rhizobial inoculants can play an important role in increasing leguminous crop yields. In temperate rhizobia, genes involved in nodulation and nitrogen fixation are usually located on one or more large plasmids (pSyms) or on symbiotic islands. In addition, other large plasmids of rhizobia carry genes that are beneficial for survival and competition of rhizobia in the rhizosphere. Conjugative transfer of these large plasmids thus plays an important role in the evolution of rhizobia. Therefore, understanding the mechanism of conjugative transfer of large rhizobial plasmids provides foundations for maintaining, monitoring, and predicting the behaviour of these plasmids during field release events. In this minireview, we summarize two types of known rhizobial conjugative plasmids, including quorum sensing regulated plasmids and RctA-repressed plasmids. We provide evidence for the existence of a third type of conjugative plasmid, including pRleVF39c in Rhizobium leguminosarum bv. viciae strain VF39SM, and we provide a comparison of the different types of conjugation genes found in members of the rhizobia that have had their genomes sequenced so far.
35
Chen, Wen-Ming, Lionel Moulin, Cyril Bontemps, Peter Vandamme, Gilles Béna, and Catherine Boivin-Masson. "Legume Symbiotic Nitrogen Fixation byβ-Proteobacteria Is Widespread inNature." Journal of Bacteriology 185, no. 24 (December 15, 2003): 7266–72. http://dx.doi.org/10.1128/jb.185.24.7266-7272.2003.
Abstract:
ABSTRACT Following the initial discovery of two legume-nodulating Burkholderia strains (L. Moulin, A. Munive, B. Dreyfus, and C. Boivin-Masson, Nature 411:948-950, 2001), we identified as nitrogen-fixing legume symbionts at least 50 different strains of Burkholderia caribensis and Ralstonia taiwanensis, all belonging to the β-subclass of proteobacteria, thus extending the phylogenetic diversity of the rhizobia. R. taiwanensis was found to represent 93% of the Mimosa isolates in Taiwan, indicating thatβ -proteobacteria can be the specific symbionts of a legume. The nod genes of rhizobial β-proteobacteria (β-rhizobia) are very similar to those of rhizobia from theα -subclass (α-rhizobia), strongly supporting the hypothesis of the unique origin of common nod genes. Theβ -rhizobial nod genes are located on a 0.5-Mb plasmid, together with the nifH gene, in R. taiwanensis and Burkholderia phymatum. Phylogenetic analysis of available nodA gene sequences clustered β-rhizobial sequences in two nodA lineages intertwined with α-rhizobial sequences. On the other hand, theβ -rhizobia were grouped with free-living nitrogen-fixingβ -proteobacteria on the basis of the nifH phylogenetic tree. These findings suggest that β-rhizobia evolved from diazotrophs through multiple lateral nod gene transfers.
36
De Sousa, Juliani Barbosa, Leonardo Lima Bandeira, Valéria Maria Araújo Silva, Franciandro Dantas Dos Santos, Fernando Gouveia Cavalcante, Paulo Ivan Fernandes Júnior, Claudia Miranda Martins, and Suzana Cláudia Silveira Martins. "In Vitro Coinoculation Between Actinobacteria and Diazotrophic Nodulating Bacteria from the Semiarid." Revista de Gestão Social e Ambiental 17, no. 9 (September 13, 2023): e04127. http://dx.doi.org/10.24857/rgsa.v17n9-007.
Abstract:
Purpose: To evaluate the potential of actinobacterial strains from the Brazilian semiarid to establish facilitation relationships with native rhizobia from the same region.
Theoretical framework: The study is based on the ecological and biotechnological importance of soil actinobacteria, producers of biosurfactants and enzymes, and of nitrogen-fixing rhizobia in legumes.
Method: 50 strains of actinobacteria were isolated from soils from Ceará with different levels of anthropization and 19 strains of rhizobia using cowpea. The morphological, cultural and micromorphological characterization of the strains was performed, as well as the evaluation of their enzymatic profiles. In vitro facilitation tests were conducted between cellulolytic actinobacteria and non-cellulolytic rhizobia.
Results: The soil areas presented a similar composition of actinobacteria, but strains from the anthropized area showed higher enzymatic activity. Two Streptomyces strains promoted the growth of non-cellulolytic rhizobia in vitro, indicating potential application as bioinoculants in microbial consortia.
Conclusions: The study contributes to the knowledge of the interaction between beneficial microbial groups from the semiarid region and their possible biotechnological use in agriculture.
Originality/value: Works on coinoculation between actinobacteria and rhizobia from semiarid soils are scarce.
37
Drew, E. A., N. Charman, R. Dingemanse, E. Hall, and R. A. Ballard. "Symbiotic performance of Mediterranean Trifolium spp. with naturalised soil rhizobia." Crop and Pasture Science 62, no. 10 (2011): 903. http://dx.doi.org/10.1071/cp11047.
Abstract:
Naturalised soil rhizobia that nodulate clover occur in high number and are known to vary in their symbiotic performance (SP) with subterranean clover (Trifolium subterraneum L.). However, the extent of suboptimal fixation across a range of other clover species is not well understood. T. subterraneum and nine other annual clover species of Mediterranean origin were evaluated for their SP in combination with the naturalised clover rhizobia in 71 Australian soils and five strains of Rhizobium leguminosarum bv. trifolii that have been used in the inoculants produced for clovers. The most probable number method, using subterranean clover as the trap plant was used to estimate the number of clover rhizobia in the soils. Ninety-two percent of soils tested contained more than 1000 rhizobia/g. An extract of each soil, or strain of rhizobia was used to inoculate plants growing in N-deficient media in the greenhouse. Plants were grown for 4 weeks after inoculation and shoot dry matter determined and expressed as a percentage of the ‘best’ soil rhizobia treatment, to provide a proportional measure of SP for each clover species. SP (mean of clover species) ranged from 96% with the current inoculant strain for annual clovers (WSM1325) down to 48% with former inoculant strain WU95. When inoculated with soils predominantly from mainland Australia, SP (mean of soil treatments) of the different Trifolium spp. was 55% (resupinatum), 53–47% (subterraneum), 50% (nigrescens), 49% (michelianum), 48% (isthmocarpum), 38% (hirtum), 35% (purpureum), 32% (vesiculosum), 25% (spumosum) and 21% (glanduliferum). Within each of the clover species, SP resulting from individual soil treatments ranged from 100% (by definition for the best soil treatment) down to close to zero. Trifolium glanduliferum formed nodules readily with the inoculant strains but nodulation was erratic with the rhizobia in many soils. It is therefore proposed that the naturalised rhizobia in many soils are unlikely to be inoculant strains. This research demonstrates symbiotic efficiency across annual clover species is compromised where diverse populations of clover rhizobia have naturalised in soils.
38
Pollak, Shaul, and Otto X. Cordero. "Rhizobiome shields plants from infection." Nature Microbiology 5, no. 8 (July 24, 2020): 978–79. http://dx.doi.org/10.1038/s41564-020-0766-1.
39
Simonsen, Anna K., Shery Han, Phil Rekret, Christine S. Rentschler, Katy D. Heath, and John R. Stinchcombe. "Short-term fertilizer application alters phenotypic traits of symbiotic nitrogen fixing bacteria." PeerJ 3 (October 8, 2015): e1291. http://dx.doi.org/10.7717/peerj.1291.
Abstract:
Fertilizer application is a common anthropogenic alteration to terrestrial systems. Increased nutrient input can impact soil microbial diversity or function directly through altered soil environments, or indirectly through plant-microbe feedbacks, with potentially important effects on ecologically-important plant-associated mutualists. We investigated the impacts of plant fertilizer, containing all common macro and micronutrients on symbiotic nitrogen-fixing bacteria (rhizobia), a group of bacteria that are important for plant productivity and ecosystem function. We collected rhizobia nodule isolates from natural field soil that was treated with slow-release plant fertilizer over a single growing season and compared phenotypic traits related to free-living growth and host partner quality in these isolates to those of rhizobia from unfertilized soils. Through a series of single inoculation assays in controlled glasshouse conditions, we found that isolates from fertilized field soil provided legume hosts with higher mutualistic benefits. Through growth assays on media containing variable plant fertilizer concentrations, we found that plant fertilizer was generally beneficial for rhizobia growth. Rhizobia isolated from fertilized field soil had higher growth rates in the presence of plant fertilizer compared to isolates from unfertilized field soil, indicating that plant fertilizer application favoured rhizobia isolates with higher abilities to utilize fertilizer for free-living growth. We found a positive correlation between growth responses to fertilizer and mutualism benefits among isolates from fertilized field soil, demonstrating that variable plant fertilizer induces context-dependent genetic correlations, potentially changing the evolutionary trajectory of either trait through increased trait dependencies. Our study shows that short-term application is sufficient to alter the composition of rhizobia isolates in the population or community, either directly though changes in the soil chemistry or indirectly through altered host legume feedbacks, and is potentially a strong selective agent acting on natural rhizobia populations.
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O'Hara, G. W. "Nutritional constraints on root nodule bacteria affecting symbiotic nitrogen fixation: a review." Australian Journal of Experimental Agriculture 41, no. 3 (2001): 417. http://dx.doi.org/10.1071/ea00087.
Abstract:
Root nodule bacteria require access to adequate concentrations of mineral nutrients for metabolic processes to enable their survival and growth as free-living soil saprophytes, and in their symbiotic relationship with legumes. Essential nutrients, with a direct requirement in metabolism of rhizobia are carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, iron, manganese, copper, zinc, molybdenum, nickel, cobalt and selenium. Boron does not seem to be required by rhizobia, but is essential for the establishment of effective legume symbioses. Nutrient constraints can affect both free-living and symbiotic forms of root nodule bacteria, but whether they do is a function of a complex series of events and interactions. Important physiological characteristics of rhizobia involved in, or affected by, their mineral nutrition include nutrient uptake, growth rate, gene regulation, nutrient storage, survival, genetic exchange and the viable non-culturable state. There is considerable variation between genera, species and strains of rhizobia in their response to nutrient deficiency. The effects of nutrient deficiencies on free-living rhizobia in the soil are poorly understood. Competition between strains of rhizobia for limiting phosphorus and iron in the rhizosphere may affect their ability to nodulate legumes. Processes in the development of some legume symbioses specifically require calcium, cobalt, copper, iron, potassium, molybdenum, nickel, phosphorus, selenium, zinc and boron. Limitations of phosphorus, calcium, iron and molybdenum in particular, can reduce legume productivity by affecting nodule development and function. The effects of nutrient deficiencies on rhizobia–legume signalling are not understood. The supply of essential inorganic nutrients to bacteroids in relation to nutrient partitioning in nodule tissues and nutrient transport to the symbiosome may affect effectiveness of nitrogen fixation. An integration of molecular approaches with more traditional biochemical, physiological and field-based studies is needed to improve understanding of the agricultural importance of rhizobia response to nutrient stress.
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SMIRNOVA, I., A. SADANOV, G. BAIMAKHANOVA, E. FAIZULINA, and L. TATARKINA. "USING SALT-TOLERANT RHIZOBIA TO IMPROVE THE SOYBEAN (GLYCINE MAX) RESILIENCE TO SALINITY." SABRAO Journal of Breeding and Genetics 55, no. 3 (June 30, 2023): 810–24. http://dx.doi.org/10.54910/sabrao2023.55.3.17.
Abstract:
Soybean (Glycine max [L.] Merr.) is an economically important oilseed crop with an annual increase in growing grain demand. Soybean is a moderately salt-tolerant crop; however, salt stress conditions can affect its growth and yield-related traits and, eventually, reduce productivity. In saline soils, one of the techniques to increase soybean productivity is to use rhizobia inoculation. Although, using industrial rhizobia-based biofertilizers is often ineffective due to their lack of adaptability to salinity. Injecting soybeans with salt-tolerant and growth-promoting rhizobia helps mitigate the effects of salt stress harmful to crop plants. The recent study sought to isolate local strains of salt-tolerant rhizobia, studying its ability to increase soybean tolerance to salt stress conditions. Twenty-four local salttolerant rhizobium isolates underwent isolation from root nodules of soybean grown on saline soils. Studying their basic morphological and biochemical characteristics and ability to withstand salt stress led to the final selection of five salt-tolerant strains. The rhizobium strains were able to synthesize metabolites that stimulate growth and help reduce salt stress in plants. The study of rhizobia nodulation ability under saline conditions resulted in selecting the three most efficient strains from the Bradyrhizobium japonicum species. Inoculation of soybean seeds with salt-tolerant rhizobia proved to mitigate the adverse effects of salinity on plant growth by increasing the root size and the number of nodules in the roots. Thus, the study establishes that inoculation of soybean seeds with local salttolerant rhizobia enhances soybean tolerance to salt stress and improves crop growth and adaptation to soil salinity. Using isolated local strains of salt-tolerant rhizobia will help provide a key and environmentally friendly approach to solving the problem of salt stress for sustainable agriculture.
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Ruiz, Bryan, Åsa Frostegård, Claude Bruand, and Eliane Meilhoc. "Rhizobia: highways to NO." Biochemical Society Transactions 49, no. 1 (February 5, 2021): 495–505. http://dx.doi.org/10.1042/bst20200989.
Abstract:
The interaction between rhizobia and their legume host plants conduces to the formation of specialized root organs called nodules where rhizobia differentiate into bacteroids which fix atmospheric nitrogen to the benefit of the plant. This beneficial symbiosis is of importance in the context of sustainable agriculture as legumes do not require the addition of nitrogen fertilizer to grow. Interestingly, nitric oxide (NO) has been detected at various steps of the rhizobium–legume symbiosis where it has been shown to play multifaceted roles. Both bacterial and plant partners are involved in NO synthesis in nodules. To better understand the role of NO, and in particular the role of bacterial NO, at all steps of rhizobia–legumes interaction, the enzymatic sources of NO have to be elucidated. In this review, we discuss different enzymatic reactions by which rhizobia may potentially produce NO. We argue that there is most probably no NO synthase activity in rhizobia, and that instead the NO2− reductase nirK, which is part of the denitrification pathway, is the main bacterial source of NO. The nitrate assimilation pathway might contribute to NO production but only when denitrification is active. The different approaches to measure NO in rhizobia are also addressed.
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Bessadok, Khouloud, Salvadora Navarro-Torre, Eloísa Pajuelo, Enrique Mateos-Naranjo, Susana Redondo-Gómez, Miguel Ángel Caviedes, Amira Fterich, Mohamed Mars, and Ignacio D. Rodríguez-Llorente. "The ACC-Deaminase Producing Bacterium Variovorax sp. CT7.15 as a Tool for Improving Calicotome villosa Nodulation and Growth in Arid Regions of Tunisia." Microorganisms 8, no. 4 (April 9, 2020): 541. http://dx.doi.org/10.3390/microorganisms8040541.
Abstract:
Calicotome villosa is a spontaneous Mediterranean legume that can be a good candidate as pioneer plants to limit regression of vegetation cover and loss of biodiversity in Tunisian arid soils. In order to grow legumes in such soils, pairing rhizobia and nodule associated bacteria (NAB) might provide numerous advantages. In this work, cultivable biodiversity of rhizobial symbionts and NAB in nodules of C. villosa plants growing in five arid regions of south Tunisia was characterized. Phylogenetic analysis using 16S rDNA gene, dnak, recA and nodD sequences separated nodule-forming bacteria in six clades associated to genera Ensifer, Neorhizobium, Phyllobacterium and Rhizobium. Among NAB, the strain Variovorax sp. CT7.15 was selected due to its capacity to solubilise phosphate and, more interestingly, its high level of aminocyclopropane-1-carboxylate deaminase (ACC deaminase) activity. C. villosa plants were inoculated with representative rhizobia of each phylogenetic group and co-inoculated with the same rhizobia and strain CT7.15. Compared with single rhizobia inoculation, co-inoculation significantly improved plant growth and nodulation, ameliorated plant physiological state and increased nitrogen content in the plants, independently of the rhizobia used. These results support the benefits of pairing rhizobia and selected NAB to promote legume growth in arid or degraded soils.
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Lupwayi, N. Z., G. W. Clayton, K. G. Hanson, W. A. Rice, and V. O. Biederbeck. "Endophytic rhizobia in barley, wheat and canola roots." Canadian Journal of Plant Science 84, no. 1 (January 1, 2004): 37–45. http://dx.doi.org/10.4141/p03-087.
Abstract:
Endophytic rhizobia have been shown to improve the nutrition of nonlegume crops. The objective of this work was to investigate the effects of field pea (Pisum sativum)-based crop rotations on endophytic rhizobia in roots of cereal and oilseed crops. Barley (Hordeum vulgare), wheat (Triticum aestivum) and canola (Brassica rapa) were each grown (a) following inoculated peas, (b) following uninoculated peas or (c) in monoculture. At flag-leaf or flowering growth stage, populations of endophytic rhizobia were usually in the order: crop following uninoculated peas (up to 7244 cells g-1 root DM) > crop following inoculated peas (up to 1660 cells g-1 root DM) > crop grown in monoculture (< 10 cells g-1 root DM). At one of three sites, there were significant positive correlations between endophytic rhizobia and crop N and yield. Populations of rhizobia in bulk soil, rhizosphere, or rhizoplane of nonlegume roots were greater where nonlegume crops were preceded by peas (inoculated or uninoculated) than where they were grown in monoculture. Significant positive correlations between populations of these rhizobia outside roots and crop N or yields were observed at each site. Key words: Crop rotation, inoculation, nitrogen fixation, plant growth-promoting rhizobacteria (PGPR), rhizosphere
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Ondieki, Damaris K., Evans N. Nyaboga, John M. Wagacha, and Francis B. Mwaura. "Morphological and Genetic Diversity of Rhizobia Nodulating Cowpea (Vigna unguiculataL.) from Agricultural Soils of Lower Eastern Kenya." International Journal of Microbiology 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/8684921.
Abstract:
Limited nitrogen (N) content in the soil is a major challenge to sustainable and high crop production in many developing countries. The nitrogen fixing symbiosis of legumes with rhizobia plays an important role in supplying sufficient N for legumes and subsequent nonleguminous crops. To identify rhizobia strains which are suitable for bioinoculant production, characterization of rhizobia is a prerequisite. The objective of this study was to assess the morphological and genetic diversity of rhizobia that nodulates cowpea in agricultural soils of lower eastern Kenya. Twenty-eight rhizobia isolates were recovered from soil samples collected from farmers’ fields in Machakos, Makueni, and Kitui counties in lower eastern Kenya and characterized based on morphological characteristics. Thirteen representative isolates were selected and characterized using BOX repetitive element PCR fingerprinting. Based on the dendrogram generated from morphological characteristics, the test isolates were distributed into two major clusters at a similarity of 75%. Phylogenetic tree, based on BOX repetitive element PCR, grouped the isolates into two clusters at 90% similarity level. The clustering of the isolates did not show a relationship to the origin of soil samples, although the isolates were genetically diverse. This study is a prerequisite to the selection of suitable cowpea rhizobia to develop bioinoculants for sustainable crop production in Kenya.
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Quigley, P. E., P. J. Cunningham, M. Hannah, G. N. Ward, and T. Morgan. "Symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii collected from pastures in south-western Victoria." Australian Journal of Experimental Agriculture 37, no. 6 (1997): 623. http://dx.doi.org/10.1071/ea96089.
Abstract:
Summary. The whole-soil inoculation method was used to assess the symbiotic effectiveness of rhizobia populations in soils collected from 18 randomly-selected pastures in south-western Victoria. This was part of a larger study which described the condition of pasture within this region. Based on the shoot weights of test subterranean clover plants, cv. Mount Barker, effectiveness varied from 36 to 94% depending on the site of rhizobia collection. This range was wider than that found in an earlier survey of rhizobia effectiveness conducted nearby. WU95, the commercial inoculant for subterranean clover, was significantly more effective than 9 of the rhizobia samples. Rhizobia from 2 sites were especially poor and their effectiveness (37%) was not significantly different from the nil inoculum control (28%). Symbiotic effectiveness was not related to soil pH, available sulfur, available phosphorus, total nitrogen or mean annual rainfall for each site where rhizobia were collected. After pooling data for all sites, the shoot weights were significantly related to the proportions of plants with nodules assigned high nodulation scores. In contrast, low scores, within 1 of 6 categories, did not significantly affect shoot weight. The technique of using mean nodulation score was less capable of discriminating differences in symbiotic effectiveness, compared with assessment based on test plant weight.
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GUDU, S. O., P. O. KISINYO, E. T. MAKATIANI, D. W. ODEE, J. F. O. ESEGU, S. A. O. SHAMCHAMA, C. O. OTHIENO, J. R. OKALEBO, J. R. OSIYO, and J. O. OWUOCHE. "SCREENING OF SESBANIA FOR TOLERANCE TO ALUMINUM TOXICITY AND SYMBIOTIC EFFECTIVENESS WITH ACID TOLERANT RHIZOBIA STRAINS IN ACID SOIL IN WESTERN KENYA." Experimental Agriculture 45, no. 4 (August 11, 2009): 417–27. http://dx.doi.org/10.1017/s0014479709990044.
Abstract:
SUMMARYNitrogen fixation by leguminous trees such as sesbania (Sesbania sesban) in acid soils is limited by aluminium (Al) toxicity and phosphorus (P) deficiency. We screened 214 East African sesbania accessions for Al toxicity tolerance, P use efficiency and sesbania–rhizobia symbiosis. Aluminium toxicity tolerance or sensitivity was measured by the relative root elongation index. Highly Al tolerant and sensitive accessions were screened for P use efficiency. Highly P use efficient and Al sensitive accessions were assessed for symbiotic effectiveness with acid tolerant rhizobia. Eighty-eight per cent of the accessions were Al toxicity tolerant. High Al levels reduced shoot P content by 88% and total dry matter (TDM) by 83%. P addition increased shoot P content and TDM. Rhizobia inoculation increased nodulation by 28–82%, shoot N content by 28–45% and TDM by 15–34% in the low rhizobia density acid soil of Bumala, Kenya. P use efficient accessions had higher nodulation, shoot N content and TDM in the ranges 32–70, 20–52 and 22–36%, respectively, compared to sensitive genotypes. The combination of sesbania accession (SSUG10) and rhizobia strain ASs48 was superior in shoot N accumulation. Inoculation of P use efficient germplasm with acid tolerant rhizobia can improve N-rich biomass accumulation suitable for N replenishment in acid soils.
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Hamilton, Leo J., Kevin F. M. Reed, Elainne M. A. Leach, and John Brockwell. "Corrigendum to: Boron deficiency in pasture based on subterranean clover (Trifolium subterraneum L.) is linked to symbiotic malfunction." Crop and Pasture Science 68, no. 8 (2017): 805. http://dx.doi.org/10.1071/cp14300_co.
Abstract:
Field and glasshouse experiments confirmed the occurrence of boron (B) deficiency in subterranean clover (Trifolium subterraneum L.) pasture in eastern Victoria. Diminished productivity was linked to the small-seededness of clover and the poor effectiveness of clover root-nodule bacteria (rhizobia, Rhizobium leguminosarum bv. trifolii). Productivity, especially of clover and clover seed, increased following applications of up to 6 kg B ha–1 (P B deficiency in the nodulated legume induced conditions within the plant and or its rhizobia that led to impaired nitrogen (N2) fixation. Glasshouse research indicated that populations of soil-borne rhizobia taken from B-deficient soils were poorly effective in N2 fixation and that rhizobia from soils growing subterranean clover cv. Leura were significantly less effective (P Additionally, subterranean clover seed generated in B-deficient soils was at least one-third smaller than the seed of commercial seed but responded to inoculation with effective rhizobia. This indicated that any symbiotic malfunction of clover from B-deficient soils was not due to an inability to respond to nitrogen per se. On the other hand, cv. Leura from B-deficient soils fixed significantly less N2 than commercial cv. Leura when each was inoculated with rhizobia from B-deficient soils.
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Takil, Engin, and Nihal Kayan. "Nitrogen Inhibators and Rhizobia Can Improve Yield and Yield Components in Bean." Romanian Agricultural Research 40 (2023): 131–38. http://dx.doi.org/10.59665/rar4012.
Abstract:
The aim of this study is investigation of the effects of rhizobia and different nitrogen fertilizer types and doses on yield and some yield components for bean. The field experiment was conducted during the 2017 and 2018 at the experimental area of the Faculty of Agriculture, Eskisehir Osmangazi University, Eskisehir, Turkey. The experiments were laid out as a randomized complete block design in a factorial arrangement and replicated four times per treatment. In this study, rhizobia and non-rhizobia were investigated at different nitrogen fertilizer types and doses (control, 25 kg ha-1 AS, 25 kg ha-1 DMPP, 50 kg ha-1 AS and 50 kg ha-1 DMPP). Bean varieties Goynuk-98 was used research material. The effects of year were significantly for all of the investigated characters but differences between the rhizobia and nitrogen fertilization were significant were all of the investigated characters except for plant emergence number. All of the investigated characters were higher in first year than second year due to climatic conditions. Rhizobia inoculation was increased yield and yield components. 50 kg ha-1 DMPP nitrogen fertilization types and doses were provided highest values for investigated characters and grain yield. Inoculation with rhizobia and 50 kg ha-1 DMPP application can be recommended for beans in Eskişehir conditions.
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Silva, Valéria Maria Araujo, Claudia Miranda Martins, Fernando Gouveia Cavalcante, Karoline Alves Ramos, Leandro Lopes da Silva, Francisca Gleire Rodrigues de Menezes, Rogério Parentoni Martins, and Suzana Cláudia Silveira Martins. "Cross-Feeding Among Soil Bacterial Populations: Selection and Characterization of Potential Bio-inoculants." Journal of Agricultural Science 11, no. 5 (April 15, 2019): 23. http://dx.doi.org/10.5539/jas.v11n5p23.
Abstract:
The biological nitrogen fixation constitutes a strategy to accelerate soil reclamation and the symbiotic systems Rhizobium-legume is the major N2-fixing in which the enzyme carboxymethyl cellulase plays a key role. As many rhizobia species are cellulase negative, the association with cellulolytic bacteria can be a strategy for the recovery of degraded ecosystems. It has been hypothesized that the sharing of resources should mostly be prevalent among phylogenetically and metabolically different species. Accordingly, twenty-seven actinobacteria isolates from Actinobacteria phyla and twenty-six rhizobia isolates from Proteobacteria phyla were selected from the bacterial collection of the Laboratory of Environmental Microbiology of the Federal University of Ceará. The presence of cellulolytic activity was observed for the rhizobia isolates at 28 °C and for actinobacteria isolates at 28, 39, 41, 43 and 45 °C. Rhizobia isolates deficient in cellulase and actinobacteria isolates with enzymatic activity detected at higher temperature were selected and characterized. The antagonism between isolates of two groups was tested and the pairs antagonistic were eliminated. The cross-feeding test between actinobacteria and rhizobia isolates was realized in a chemically defined medium containing carboxymethyl-cellulose as the only carbon and energy source. Growth of rhizobia strains in 50% of the pairwise indicated that the cellulose hydrolyzed by actinobacteria was used as substrate for the growth of the rhizobia. The Bradyrhizobium strain R10 associated with Streptomyces strains A09 and A18 and Nocardia A11 are promissory inoculants for recovery of semi-arid regions.