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1.
Chickpea (Cicer arietinum L.) nodulation variants of two cultivars ICC 4948 and ICC 5003 were used as trap plants to isolate 385 native rhizobia from CCS Haryana Agricultural University, Hisar farm soil. After authentication and considering growth characteristics, selected 110 rhizobia revealed immense molecular diversity using the profiles of DNA fragments generated by Polymerase chain reaction (PCR) with enterobacterial repetitive intergeneric consensus (ERIC) sequences. Low nodulating variants of cvs ICC 4948 and ICC 5003 were able to trap more numbers of rhizobial genotypes, namely seven as compared four to five by high nodulating variants of these cultivars. Overall eight rhizobial genotypes were trapped by the chickpea cultivars. Rhizobial isolates from same nodule or same plants were present in the same or different clusters and few isolates showed 100% similarity also. Based on nodules from a plant, nodulation variant or cultivar, rhizobia could not be differentiated and no exclusive cluster was formed by either rhizobial isolates from low or high nodulating variants of both the cultivars. Two most efficient rhizobial isolates LN 707b and LN 7007 were characterized by amplification and sequencing of 16S rRNA gene. Rhizobial isolate LN 707b showed more than 98% similarity with Mesorhizobium sp SH 2851 and Mesorhizobium mediterraneum. Another isolate LN 7007 showed more than 99% similarity with the sequence of 16S r RNA gene of Mesorhizobium sp STM 398, and M. mediterraneum. So the chickpea rhizobia from Northern Indian subcontinent are proposed to be kept under M. mediterraneum strain LN707b and LN 7007.  相似文献   

2.
The present study was designed with the objective of improving the nodulation and growth of chickpea (Cicer arietinum L.) by integrating co-inoculation of Rhizobium sp. (Mesorhizobium ciceri) and plant growth promoting rhizobacteria (PGPR) carrying ACC (1-aminocyclopropane-1-carboxylate) deaminase activity with P-enriched compost (PEC) under irrigated and rainfed farming systems. PEC was prepared from fruit and vegetable waste and enriched with single super phosphate. The results demonstrated that co-inoculation significantly (P?<?0.05) increased the number of nodules per plant, nodule dry weight, pods per plant, grain yield, protein content, and total chlorophyll content under irrigated and rainfed conditions compared to inoculation with rhizobium alone. Integrating PEC with co-inoculation showed an additive effect on the nodulation and growth of chickpea under both farming systems. Analysis of leaves showed a significantly (P?<?0.05) higher photosynthetic rate and transpiration rate in comparison with inoculation with Rhizobium. Compared to irrigated farming system, co-inoculation with PEC under rainfed conditions was more beneficial in improving growth and nodulation of chickpea. Post-harvest soil analysis revealed that the integrated use of bioresources and compost enhanced microbial biomass C, available N content, dehydrogenase, and phosphomonoesterase activities.  相似文献   

3.
Compatible rhizobia strains are essential for nodulation and biological nitrogen fixation (BNF) of hairy vetch (Vicia villosa Roth, HV). We evaluated how past HV cultivation affected nodulation and BNF across host genotypes. Five groups of similar HV genotypes were inoculated with soil dilutions from six paired fields, three with 10-year HV cultivation history (HV+) and three with no history (HV?), and used to determine efficiency of rhizobia nodulation and BNF. Nodulation was equated to nodule number and mass, BNF to plant N and Rhizobium leguminosarum biovar viceae (Rlv) soil cell counts using qPCR to generate an amplicon of targeted Rlv nodD genes. Both HV cultivation history and genotype affected BNF parameters. Plants inoculated with HV+ soil dilutions averaged 60 and 70 % greater nodule number and mass, respectively. Such plants also had greater biomass and tissue N than those inoculated with HV? soil. Plant biomass and tissue N were strongly correlated to nodule mass (r 2?=?0.80 and 0.50, respectively), while correlations to nodule number were low (r 2?=?0.50 and 0.31, respectively). Although hairy vetch rhizobia occur naturally in soils, past cultivation of HV was shown in this study to enhance nodulation gene-carrying Rlv population size and/or efficiency of rhizobia capable of nodulation and N fixation.  相似文献   

4.
Chickpea Rhizobium populations in soil samples from research stations and farmers' fields in different geographic regions of India ranged from <10 to > 104 rhizobia g−1 soil. Fields on research stations with a known history of chickpea cropping had more rhizobia (calc. 103 to 105 rhizobia g1&#x0304; soil) than the majority of farmers' fields (calc. < 10 to 103 rhizobia g−1 soil). In the absence of chickpea in the cropping pattern, soils generally had < 102 rhizobia g1&#x0304; and crops in such fields nodulated poorly. However, poor nodulation was also observed when populations of rhizobia were high, indicating that other factors were also important for nodulation. There was no obvious consistent correlation of Rhizobium population with pH, electrical conductivity and nitrate-nitrogen status of the soil.Rhizobium populations declined with soil depth and were highest (about 104 rhizobia g−1 soil) in the top 30 cm of the profile and lowest, but still present (calc. 103–103 rhizobia g'1 soil), at 90–120 cm—a depth where no nodules are found. Populations fluctuated most in the top 5 cm, being reduced during periods of high soil temperature in summer and recovering after rains. Rhizobium populations were at a maximum after chickpea but survived well under pigeonpea, groundnut and maize. When rice followed an inoculated chickpea crop, there was about a 100-fold decrease in the Rhizobium population.  相似文献   

5.
Three experiments were conducted in order to investigate the effect of water deficiency on nodulation, rhizobial diversity and growth of common bean. In the first experiment, the effect of water deficiency was studied on two soil samples under glasshouse conditions. A significant decrease in nodulation and shoot dry weight production was observed. The molecular characterization of the root nodule isolates by PCR-RFLP of 16S rRNA and nodC genes showed that the nodulation by Rhizobium etli was severely inhibited. The in vitro analysis of salt tolerance indicated that drought stress favoured nodulation by salt-tolerant strains. In the second experiment, the effect of water deficiency was studied on sterilized sand using Rhizobium tropici CIAT899T and Ensifer meliloti bv. mediterranense 4H41 as inoculants. The results showed that strain 4H41, which is the more salt tolerant, was more competitive and more effective under water deficiency than strain CIAT899T. In the third experiment, the strain 4H41 was used to inoculate four fields. A significant increase in nodule number, shoot dry weight and grain yield was observed even in the non-irrigated soils. This work constitutes the first report of a strain enhancing the growth and the grain yield of common bean under water deficiency.  相似文献   

6.
Changes in the populations of Rhizobium strains CB756str, CB985 and CB1024strspc in the rhizospheres of cowpea (Vigna unguiculata) and black gram (V. mungo) grown at three sites were evaluated. The population dynamics of the three rhizobia varied with soil type but the strain responses on the two legumes were generally similar. Most noticeable was the ability of CB756str to grow in the sandy soil (Beerwah) but not in the heavy clays (Narayen and Emerald). In contrast, the levels of CB1024strspc and CB985 generally increased in the clay soils.Nodulation (% due to the inoculum strain) did not always reflect events within the rhizosphere. Although not suited to Narayen, CB756str formed a similar proportion of the nodule population of black gram as CB1024strspc but this may have been due to higher seed inoculum levels of CB756str. At Emerald nodulation by all three strains of rhizobia was poor regardless of the success in colonization of the rhizosphere. Successful competition for nodule sites by native rhizobia may contribute to this discrepancy between Narayen and Emerald although lower seed inoculum levels at Emerald may also have been important.Nodule decay was consistently associated with a large increase in the number of rhizobia per root system. This is likely to be important in the survival of strains into the following season.Comparisons of nodulation by parent and mutant rhizobia suggested that resistance to antibotics may have slightly reduced nodule forming ability for CB1024strspc on black gram at Emerald.  相似文献   

7.
Chickpea [Cicer arietinum (L.)] and pigeon pea [Cajanus cajan (L.) Millsp.] were grown outside in large clay pots from 1992 to 1995 in Edmond, Oklahoma. Plants were studied to evaluate nodulation, nitrogenase activity, and shoot dry weight (DW) of ‘ICCV-2’ and ‘Sarah’ chickpea inoculated with multistrain, TAL 1148, and TAL 480 Bradyrhizobium, as well as ‘Georgia-1’ and ‘ICPL-87’, pigeon pea inoculated with multistrain TAL 1127, and TAL 1132 Bradyrhizobium. Following wheat [Triticum aestivum (L.) emend. Thell.] harvests in the spring, legumes were planted in the summer and harvested at three successive dates during the following months. Leaves and stems from remaining plants were incorporated into the soil after the last harvest. Across year, chickpea measurements were sensitive to temperature and precipitation whereas pigeon pea measurements were sensitive to length of growing season as well as climate. Pigeon pea consistently demonstrated higher nitrogen-fixing capacity and shoot DW compared with chickpea. Nodule and shoot DW of both species increased with plant age whereas nodule count and nitrogenase activity generally increased with plant age and leveled off or decreased at flowering. Sarah chickpea demonstrated higher nodule count and nodule DW than ICCV-2, as did the Georgia-1 pigeon pea compared with ICPL-87. Shoot DW of Georgia-1 pigeon pea was generally higher than that of ICPL-87. Multistrain inoculum improved nodulation and shoot DW of chickpea, and TAL 1127 improved nodulation of pigeon pea compared with other treatments. These results indicate that specific chickpea and pigeon pea cultivars, along with appropriate Bradyrhizobium strains, may improve nitrogen fixation and DW of these species.  相似文献   

8.
Summary Six fast-growing soybean rhizobia (Rhizobium fredii) and thirteen slow-growing soybean rhizobia (Bradyrhizobium japonicum) were examined for resistance to 10 antibiotics. Axenic studies were carried out to determine the competitiveness of dual-strain inocula consisting of fast- and slow-growing rhizobia isolated from subtropical-tropical soils for nodule occupancy on a hybrid of Asian and US soybean cultivars. Nodule occupancy was determined by intrinsic resistance to erythromycin and neomycin. The results showed wide variability in resistance to 10 antibiotics for fast- and slow-growing rhizobia. The intrinsic antibiotic resistance of fast- and slow-growing rhizobia was extremely high against nalidixic acid (400 g ml–1) and penicillin (200 g ml–1). The competitive ability of inoculant strains for nodule occupancy varied for different combination sets and with the plant growing media. Our results show that fast-growing rhizobia nodulate a hybrid of Asian and US soybean cultivars. Fast-growing soybean rhizobia did not completely exclude nodulation by the slow-growing strains, which formed 0–79% nodules, depending on the strain used in the inoculum.  相似文献   

9.
This study aimed at investigating mechanisms of salt tolerance and ionic relations of chickpea (Cicer arietinum L.) cultivars with different nitrogen (N) sources. Two resistant genotypes, ILC‐205 and ILC‐1919, were subjected to four levels of salinity (0.5, 3.0, 6.0, and 9.0 dS m‐1). Nitrogen sources consisted of inoculation with two resistant Rhizobium strains, CP‐29 and CP‐32, mineral N additions, and no N application. Data was collected on root and shoot contents of sodium (Na+) chlorine, (Cl‐,) and potassium (K+), and shoot to root Na+ratio, as well as shoot K+ to Na+ ratio. Salinity affected shoot Na+ and Cl‐contents, but nodulating plants had higher shoot Na+ contents than plants supplied with mineral N. Shoot to root Na+ ratios were lower in the mineral N treatment than in nodulating treatments at 3.0 dS m‐1, indicating that root compartmentalization and shoot exclusion were only possible at low salinities. Potassium levels of nodulating plant shoots were lower than those of non‐nodulating plants only at low salinities. N‐source significantly affected shoot K+/Na+ ratio, with nodulating plants having lower ratios than non‐nodulating plants, indicating that rhizobial infection or nodule formation may lead to salt entry curtailing the selective ability of chickpea roots.  相似文献   

10.
Effects of phosphorus (P) deficiency on nodulation were examined in soybean grown in nutrient solution for 7 weeks. Increasing P supply increased shoot growth of nitrogen (N2)-fixing plants from week 5 and that of nitrate-fed plant from week 4 after treatment. Nitrogen (N2)-fixing plants had a greater P requirement for maximum growth at week 5. Increasing P supply from 1 to 16 μ M increased N concentration in N2-fixing plants at week 4 but did not affect it from week 5. By contrast, P deficiency increased N concentration in nitrate-fed plants. Increasing P supply improved nodule formation from week 3. Nodule mass was affected more by P supply than nodule number, which, in turn, was affected more than plant growth. However, P supply did not decrease nodule specific N2 fixation from week 5. The results suggest that P deficiency impaired symbiotic N2 fixation through delaying onset of nodule function and decreasing nodule development.  相似文献   

11.
This study was initiated to isolate, characterize and select symbiotically effective rhizobia nodulating lentil (Lens culinaris medic) and to enumerate indigenous rhizobia nodulating lentil in some Ethiopian soils. More than 84 nodule and soil samples were collected. In sand culture, only 62 isolates were authenticated as rhizobia nodulating lentil. Analyses of variance indicated that most of the parameters measured were significantly (p < 0.05) improved by inoculation, with the exception of root length. Inoculation increased shoot length, shoot dry weight and plant total nitrogen by 82.3, 196 and 452%, respectively, over negative control (without inoculation and N fertilization). The tested isolates were found to be very effective (20.9%) and effective (77.4%), with only one ineffective isolate. Indigenous rhizobia in the investigated soils ranged from 30 to 5.8 × 103 cell g?1 dry soil. A pot experiment with selected rhizobia and nitrogen fertilizer on Chefedonsa and Debrezeit soils did not show any significant difference in shoot dry weight at p < 0.05. From the study, it was observed that most Ethiopian soils were inhabited by a moderate to high number of indigenous rhizobia and rhizobia inoculation did not improve lentil productivity in the investigated soils.  相似文献   

12.
Summary Chickpea cultivars (Cicer arietinum L.) and their symbiosis with specific strains of Rhizobium spp. were examined under salt stress. The growth of rhizobia declined with NaCl concentrations increasing from 0.01 to 2% (w : v). Two Rhizobium spp. strains (F-75 and KG 31) tolerated 1.5% NaCl. Of the 10 chickpea cultivars examined, only three (Pusa 312, Pusa 212, and Pusa 240) germinated at 1.5% NaCl. The chickpea — Rhizobium spp. symbiosis was examined in the field, with soil varying in salinity from electrical conductivity (EC) 4.5 to EC 5.2 dSm-1, to identify combinations giving satisfactory yields. Significant interactions between strains and cultivars caused differential yields of nodules, dry matter, and grain. Four chickpea — Rhizobium spp. combinations, Pusa 240 and F-75 (660 kg ha-1), Pusa 240 and IC 76 (440 kg ha-1), Pusa 240 and KG 31 (390 kg ha-1), and Pusa 312 and KG 31 (380 kg ha-1), produced significantly higher grain yields in saline soil.  相似文献   

13.
The most common method of inoculating legume crops in Australia is the application of peat slurry inoculant to seed. The recent introduction of granular (solid) formulations of inoculants into the Australian market has provided the potential to apply rhizobia with greater ease, but their efficacy has not been independently evaluated. Here, we compare the efficacy of a range of experimental and commercially-available granular inoculants on chickpea, faba bean, lentil, lupin and pea crops in comparison with un-inoculated treatments, and with conventional seed-applied peat slurry inoculants. Thirty-seven field experiments were established in Victoria, South Australia and southern New South Wales over five years. Peat slurry inoculants provided effective nodulation of all legumes. Granular inoculants varied markedly in their ability to improve grain legume nodulation. The size of response depended inversely on background nodulation from soil rhizobial populations. At sites with median background nodulation, peat granules and attapulgite clay granules placed with seed resulted in nodulation similar to peat-slurry-based inoculation, but treatments with bentonite clay granules did not increase nodule numbers much above those in un-inoculated treatments. The generally lower numbers of rhizobia g−1 in the bentonite granules, translated to lower rhizobia application rate to the soil. However, differences in number of rhizobia g−1 granule did not fully explain the nodulation differences between granules. Granule moisture content and granule particle size differed markedly between granule types but their influence on nodulation was not tested. Grain yields did not differ between attapulgite granules placed with seed, peat granules and peat slurry inoculants (all well-nodulated treatments), but were lower with bentonite granule inoculants. Yield differences within sites were related to nodulation and the differences between treatments attenuated as background nodulation increased. Overall, these studies demonstrate that certain granule types have the potential to be used in Australia with grain legumes, particularly in circumstances when seed-applied inoculants are problematic, such as where seed fungicides or insecticides need to be applied. However, granular inoculant formulations differ substantially in their potential to produce nodules on a range of grain legumes.  相似文献   

14.
The shade-tolerant cover legume Calopogonium caeruleum is promiscuous in its nodulating habits. In sand culture, symbiotic effectiveness of the strains tested was variable; 6 strains of rhizobia markedly improved shoot yields and 20 increased shoot N content. In pot experiments using cultivated and non-cultivated soils, inoculation gave no significant increase in shoot yields. When grown under rubber in plantation conditions at four localities, shoot dry matter yields, N content and nodulation also were not different from uninoculated plants when sampled for up to 2 yr after planting. This occurred despite the low numbers (< 10 g?1 soil) of native rhizobia at some sites and an appreciable establishment (> 70% recovery in nodules) by the inoculant strains.  相似文献   

15.
Diversity of rhizobia nodulating Lotus corniculatus grown in geographical regions with different rainfall regimes in northern and southern Uruguay, was estimated using 168 root nodule isolates. ERIC-PCR analysis revealed no correlation between observed fingerprints and the geographical origin of isolates. Despite the commercial strain U510 has been used for decades to inoculate L. corniculatus, none of the isolates corresponded to this strain. Phylogenetic analyses using 16S rRNA and atpD genes, and ITS sequences clustered all the isolates within genus Mesorhizobium. A great majority of the isolates likely belong to the species M. huakuii, as does the commercial strain U510. The remaining isolates were closely related to either M. septentrionale or M. caraganae. Although no M. loti-like bacteria were identified, all isolates carried symbiotic genes closely related to M. loti and other narrow host range Lotus rhizobia. A significant portion of the Uruguayan isolates were as efficient as the reference strain U510 in symbiosis with L. corniculatus. A few of the isolates were also capable of nitrogen fixation in symbiosis with L. uliginosus, albeit with lower efficiency than reference strains. Our results indicate that rhizobia nodulating L. corniculatus in Uruguay are genetically and phenotypically diverse, and that the commercial strain U510 is probably not adapted to survive the Uruguayan edaphoclimatic conditions.  相似文献   

16.
We previously reported that commercial Rhizobium leguminosarum bv. trifolii inoculants failed to outcompete naturalized strains for nodule occupation of clover sown into an alkaline soil [Aust. J. Agric. Res. 53 (2002) 1019]. Two field isolates that dominated nodule occupancy at the field site were labeled with a PnifH-gusA marker. Marked strains were chosen on the basis that they were equally competitive and fixed similar amounts of nitrogen in comparison to their parental strain. The minitransposon insertions were cloned and sequence analysis revealed that neither lesion disrupted the integrity of any known gene. The marked strains were then used to follow nodule occupancy of Trifolium alexandrinum in competition against the commercial inoculant TA1 under a range of experimental conditions. In co-inoculation experiments in sand-vermiculite, TA1 outcompeted each marked field isolate for nodule occupancy. However, using TA1-inoculated seed sown into alkaline soil containing a marked field strain, it was demonstrated that by increasing the cell number of marked rhizobia in the soil and reducing the cell number of the commercial inoculant, the proportion of nodules occupied by TA1 was reduced. These studies indicate that the ability of the field isolates to dominate nodule occupancy in the alkaline field soils was most likely caused by poor commercial inoculant survival providing the advantage for naturalized soil rhizobia to initiate nodulation.  相似文献   

17.
When a bacteriocin-sensitive and a bacteriocin-resistant strain of Rhizobium were added together to plant-tubes, containing Trifolium subterraneum cv. Dwalganup seedlings, the bacteriocinresistant strain occupied less than 10% of the nodules sites. But when a bacteriocin-producer was added with the inoculum, the bacteriocin-resistant strain occupied 75% of the nodule sites. In a replicate experiment, using a different bacteriocin-sensitive strain, the proportion of the nodules formed by the bacteriocin-resistant strain was increased from 17%, in the absence of the bacteriocin-producer, to 100% in its presence.Similar experiments were set up in non-sterile soil that contained ineffective, bacteriocin-sensitive rhizobia. When an effective bacteriocin-resistant strain was inoculated with a bacteriocin-producing strain, the proportion of nodules formed by the effective strain was greater than in the absence of the bacteriocin-producer. This was because nodulation by the indigenous rhizobia was reduced in the presence of the bacteriocin-producer.Such experiments suggest that bacteriocin-producing strains of R. trifolii that reduce the nodulation success of competing bacteriocin-sensitive strains could be used to increase the proportion of nodules formed by a desired bacteriocin-resistant strain.  相似文献   

18.
Nitrogen (N) fixation by legume-Rhizobium symbiosis is important to agricultural productivity and is therefore of great economic interest. Growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. The effect of co-inoculation with plant growth-promoting rhizobacteria (PGPR) and Rhizobium, on nodulation, nitrogen fixation, and yield of common bean (Phaseolus vulgaris L.) cultivars was investigated in two consecutive years under field conditions. The PGPR strains Pseudomonas fluorescens P-93 and Azospirillum lipoferum S-21 as well as two highly effective Rhizobium strains were used in this study. Common bean seeds of three cultivars were inoculated with Rhizobium singly or in a combination with PGPR to evaluate their effect on nodulation and nitrogen fixation. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Treatment with PGPR significantly increased nodule number and dry weight, shoot dry weight, amount of nitrogen fixed as well as seed yield and protein content. Co-inoculation with Rhizobium and PGPR demonstrated a significant increase in the proportion of nitrogen derived from atmosphere. These results indicate that PGPR strains have potential to enhance the symbiotic potential of rhizobia.  相似文献   

19.
Soil cores from under senesced legume swards were partitioned into (1) soils, (2) legume roots, (3) nodules and (4) debris. The viable population of Rhizobium trifolii under subterranean clover was found to be predominantly in the nodule fraction; but with R. lupini under Serradella the distribution was more even. In commercially sown stands the rhizobia often failed to migrate from the original sown rows into the soil between the rows. The relative importance of the various fractions as contributors to the “pool” of rhizobia available for nodulation of subsequent generations of host-plants is discussed.  相似文献   

20.
A glasshouse study was undertaken to investigate the effects of the copper fungicide Kocide 101 and its residues in soil on the growth, nodulation and nitrogen fixation of beans (Phaseolus vulgaris L.). The soil used was a sandy clay loam classified as Typic Rhodustalf. The bean variety SUA 90 was used as test crop. The bean rhizobia strains CIAT 899, PV, and a local isolate were used. Kocide 101 applied at the recommended rate (equivalent to 1.7 mg kg‐1 soil) had no significant negative effects on the growth, nodulation or nitrogen fixation of bean plants. Higher levels of Kocide 101 significantly (P < 0.05) reduced plant growth, nodulation and nitrogen fixation. The bean plants inoculated with the “local isolate”; rhizobia had the highest dry matter weights, nodule numbers and nodule dry weights, and also had more N fixation. They were followed by those inoculated with the PV, strain and, lastly, those inoculated with CIAT 899. The growth and nodulation of bean plants were still curtailed by the Kocide 101 residues four months after the fungicide was first applied to the soil. Therefore, occurrence of high levels of Kocide 101 in soils can have long‐term effects on the performance of the bean‐rhizobia symbiosis.  相似文献   

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