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1.
In the current study, 18 salt-tolerant bacteria were isolated from salt-affected soil of Erzurum, Turkey. Forty-five bacterial isolates were identified and characterized by conventional and molecular techniques. These 45 sequenced isolates were identified as 16 different genus including Bacillus (19 isolates), Staphylococcus (3 isolates), Halobacillus (4 isolates), Zhihengliuella (2 isolates), Oceanobacillus (2 isolates), Halomonas (1 isolate), Nesterenkonia (2 isolates), Promicromonospora (2 isolates), Jeotgalibacillus (2 isolates), Planococcus (2 isolates), Virgibacillus (1 isolate), Terribacillus (1 isolate), Thalassobacillus (1 isolate), Marinibacillus (1 isolate), Gracilibacillus (1 isolate) and Microbacterium (1 isolate). According to the results obtained, investigated bacterial strains have high salt tolerance and significant enzyme activities that can improve soil nutrient cycling and soil fertility. The current article provides the evaluation and diversity of the potential halotolerant and halophilic bacterial strains in salt-affected soils of Erzurum, Turkey. 相似文献
2.
Sisinthy Shivaji N. Shyamala Rao L. Saisree Vipula Sheth G. S. N. Reddy Pushpa M. Bhargava 《Journal of biosciences》1988,13(4):409-414
Five cultures isolated from soil samples collected in Schirmacher oasis, Antarctica, have been identified as members of the
familyMicrococcaceae, with 3 belonging to the genusMicrococcus and two toPlanococcus. The 3Micrococcus isolates (37R, 45R and 49R) were red-pigmented and h a d ∼ 75 mol% G + C in their DNA; they were identified asMicrococcus roseus. The twoPlanococcus isolates (30Y and Lz3OR) were yellow and orange in colour, and had 43.5 and 40.9 mol % G + C in their DNA respectively; they
were identified asPlanococcus sp. 相似文献
3.
Genetic Diversity of Plant Growth Promoting Rhizobacteria Isolated from Rhizospheric Soil of Wheat Under Saline Condition 总被引:2,自引:0,他引:2
In this study, a total of 130 rhizobacteria was isolated from a saline infested zone of wheat rhizosphere, and screened for
plant growth promoting (PGP) traits at higher salt (NaCl) concentrations (2, 4, 6, and 8%). The results revealed that 24 rhizobacterial
isolates were tolerant at 8% NaCl. Although all the 24 salt tolerable isolates produced indole-3-acetic acid (IAA), while
10 isolates solubilized phosphorus, eight produced siderophore, and six produced gibberellin. However, only three isolates
showed the production of 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Diversity was analyzed through 16S rDNA-RFLP,
and of these isolates with three tetra cutter restriction enzymes (HaeIII, AluI, and MspI), the representative cluster groups were identified by 16S rDNA sequencing. Bacillus and Bacillus-derived genera were dominant which showed PGP attributes at 8% NaCl concentration. Out of 24 isolates, nitrogen fixing ability
(nif H gene) was detected in the two isolates, SU18 (Arthrobacter sp.) and SU48. 相似文献
4.
Eight bacterial isolates from the larval guts of Diamondback moths (Plutella xylostella) were tested for their plant growth–promoting (PGP) traits and effects on early plant growth. All of the strains tested positive
for nitrogen fixation and indole 3-acetic acid (IAA) and salicylic acid production but negative for hydrogen cyanide and pectinase
production. In addition, five of the isolates exhibited significant levels of tricalcium phosphate and zinc oxide solubilization;
six isolates were able to oxidize sulfur in growth media; and four isolates tested positive for chitinase and β-1,3-glucanase
activities. Based on their IAA production, six strains including four that were 1-aminocyclopropane-1-carboxylate (ACC) deaminase
positive and two that were ACC deaminase negative were tested for PGP activity on the early growth of canola and tomato seeds
under gnotobiotic conditions. Acinetobacter sp. PSGB04 significantly increased root length (41%), seedling vigor, and dry biomass (30%) of the canola test plants, whereas
Pseudomonas sp. PRGB06 inhibited the mycelial growth of Botrytis
cinerea, Colletotrichum
coccodes, C.
gleospoiroides, Rhizoctonia
solani, and Sclerotia
sclerotiorum under in vitro conditions. A significant increase, greater than that of the control, was also noted for growth parameters
of the tomato test plants when the seeds were treated with PRGB06. Therefore, the results of the present study suggest that
bacteria associated with insect larval guts possess PGP traits and positively influence plant growth. Therefore, insect gut
bacteria as effective PGP agents represent an unexplored niche and may broaden the spectrum of beneficial bacteria available
for crop production. 相似文献
5.
B. G. Anusha M. K. Naik M. Sharma 《Archives Of Phytopathology And Plant Protection》2013,46(5-6):417-442
A study was carried out to test direct and indirect antagonistic effect against Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceri (FOC), and plant growth-promoting (PGP) traits of bacteria isolated from rhizosphere soils of chickpea (Cicer arietinum L.). A total of 40 bacterial isolates were tested for their antagonistic activity against FOC and of which 10 were found to have strong antagonistic potential. These were found to be Streptomyces spp. (five isolates) and Bacillus spp. (five isolates) in the morphological and biochemical characterisation and 16S rDNA analysis. Under both greenhouse and wilt sick field conditions, the selected Streptomyces and Bacillus isolates reduced disease incidence and delayed expression of symptoms of disease, over the non-inoculated control. The PGP ability of the isolates such as nodule number, nodule weight, shoot weight, root weight, grain yield and stover yield were also demonstrated under greenhouse and field conditions over the non-inoculated control. Among the ten isolates, Streptomyces sp. AC-19 and Bacillus sp. BS-20 were found to have more potential for biocontrol of FOC and PGP in chickpea. This investigation indicates that the selected Streptomyces and Bacillus isolates have the potential to control Fusarium wilt disease and to promote plant growth in chickpea. 相似文献
6.
Yuan Gong Juan-Luan Bai Huan-Ting Yang Wen-Di Zhang You-Wei Xiong Peng Ding Sheng Qin 《Systematic and applied microbiology》2018,41(5):516-527
Actinobacteria from special habitats are of interest due to their producing of bioactive compounds and diverse ecological functions. However, little is known of the diversity and functional traits of actinobacteria inhabiting coastal salt marsh soils. We assessed actinobacterial diversity from eight coastal salt marsh rhizosphere soils from Jiangsu Province, China, using culture-based and 16S rRNA gene high throughput sequencing (HTS) methods, in addition to evaluating their plant growth-promoting (PGP) traits of isolates. Actinobacterial sequences represented 2.8%–43.0% of rhizosphere bacterial communities, as determined by HTS technique. The actinobacteria community comprised 34 families and 79 genera. In addition, 196 actinobacterial isolates were obtained, of which 92 representative isolates were selected for further 16S rRNA gene sequencing and phylogenetic analysis. The 92 strains comprised seven suborders, 12 families, and 20 genera that included several potential novel species. All representative strains were tested for their ability of producing indole acetic acid (IAA), siderophores, 1-aminocyclopropane-1-carboxylate deaminase (ACCD), hydrolytic enzymes, and phosphate solubilization. Based on the presence of multiple PGP traits, two strains, Streptomyces sp. KLBMP S0051 and Micromonospora sp. KLBMP S0019 were selected for inoculation of wheat seeds grown under salt stress. Both strains promoted seed germination, and KLBMP S0019 significantly enhanced seedling growth under NaCl stress. Our study demonstrates that coastal salt marsh rhizosphere soils harbor a diverse reservoir of actinobacteria that are potential resources for the discovery of novel species and functions. Moreover, several of the isolates identified here are good candidates as PGP bacteria that may contribute to plant adaptions to saline soils. 相似文献
7.
Sang-Mo Kang Abdul Latif Khan Muhammad Hamayun Javid Hussain Gil-Jae Joo Young-Hyun You Jong-Guk Kim In-Jung Lee 《Journal of microbiology (Seoul, Korea)》2012,50(6):902-909
Plant growth-promoting rhizobacteria (PGPR) producing gibberellins (GAs) can be beneficial to plant growth and development. In the present study, we isolated and screened a new strain of Promicromonospora sp., SE188, isolated from soil. Promicromonospora sp. SE188 secreted GAs into its growth medium and exhibited phosphate solubilization potential. The PGPR produced physiologically active (GA1 and GA4) and inactive (GA9, GA12, GA19, GA20, GA24, GA34, and GA53) GAs in various quantities detected by GC/MS-SIM. Solanum lycopersicum (tomato) plants inoculated with Promicromonospora sp. SE188 showed a significantly higher shoot length and biomass as compared to controls where PGPR-free nutrient broth (NB) and distilled water (DW) were applied to plants. The presence of Promicromonospora sp. SE188 significantly up-regulated the non C-13 hydroxylation GA biosynthesis pathway (GA12→GA24→GA9→GA4→ GA34) in the tomato plants as compared to the NB and DW control plants. Abscisic acid, a plant stress hormone, was significantly down-regulated in the presence of Promicromonospora sp. SE188. Contrarily, salicylic acid was significantly higher in the tomato plant after Promicromonospora sp. SE188 inoculation as compared to the controls. Promicromonospora sp. SE188 showed promising stimulation of tomato plant growth. From the results it appears that Promicromonospora sp. SE188 has potential as a bio-fertilizer and should be more broadly tested in field trials for higher crop production in eco-friendly farming systems. 相似文献
8.
ikbal Agah ince Hatice Katı Hüseyin Yilmaz ismail Demir Zihni Demirbağ 《World journal of microbiology & biotechnology》2008,24(12):3005-3015
The pine processionary moth Thaumetopoea pityocampa (Den. and Schiff.) is one of the most harmful insect pest for pine species in Mediterranean countries including Turkey. The
objective of the present study is to find a more effective and safe biological control agent against T. pityocampa. Thus, we investigated the bacterial flora of the pest insect, collected from the Middle Black Sea Region of Turkey from
2003 to 2004. Based on morphological, physiological, biochemical and molecular methods, 14 different bacterial isolates were
determined. The identified bacterial flora of T. pityocampa consisted of bacteria belonging to the Enterobacteriaceae (Tp1), Arthrobacter sp. (Tp2), Staphylococcus spp. (Tp3 and 10), Bacillus subtilis (Tp4), Serratia liquefaciens (Tp5), Bacillus thuringiensis subsp. morrisoni (Tp6 and 14), an acrystalliferous form Bacillus thuringiensis (Tp7), Staphylococcus cohnii (Tp8), Bacillus licheniformis (Tp9), Bacillus pumilus (Tp11), Brevibacterium sp. (Tp12) and Bacillus simplex (Tp13). After analysing the conclusions of conventional and molecular tests Tp1 (Enterobacteriaceae), Tp2 (Arthrobacter sp.) and Tp12 (Brevibacterium sp.) were assigned as novel bacterial species. Isolate Tp5 had a promising insecticidal effect on third instar larvae of
T. pityocampa (up to 70% mortality within 10 days). 相似文献
9.
Subramaniam Gopalakrishnan Pagidi Humayun Bandru Keerthi Kiran Iyer Girish Kumar Kannan Meesala Sree Vidya Kanala Deepthi Om Rupela 《World journal of microbiology & biotechnology》2011,27(6):1313-1321
A total of 360 bacteria, isolated from the rhizospheres of a system of rice intensification (SRI) fields, were characterized
for the production of siderophore, fluorescence, indole acetic acid (IAA), hydrocyanic acid (HCN) and solubilization of phosphorus.
Of them, seven most promising isolates (SRI-156, -158, -178, -211, -229, -305 and -360) were screened for their antagonistic
potential against Macrophomina phaseolina (causes charcoal rot in sorghum) by dual culture assay, blotter paper assay and in greenhouse. All the seven isolates inhibited
M. phaseolina in dual culture assay, whereas six isolates solubilized phosphorous (except SRI-360), all seven produced siderophore, four
produced fluorescence (except SRI-178, -229 and -305), six produced IAA (except SRI-305) and five produced HCN (except SRI-158
and -305). In the blotter paper assay, no charcoal rot infection was observed in SRI-156-treated sorghum roots, indicating
complete inhibition of the pathogen, while the roots treated with the other isolates showed 49–76% lesser charcoal rot infection
compared to the control. In the antifungal activity test (in green house on sorghum), all the isolates increased shoot dry
mass by 15–23% and root dry mass by 15–20% (except SRI-158 and -360), over the control. In order to confirm the plant growth-promoting
(PGP) traits of the isolates, the green house experiment was repeated but, in the absence of M. phaseolina. The results further confirmed the PGP traits of the isolates as evidenced by increases in shoot and root dry mass, 22–100%
and 5–20%, respectively, over the control. The sequences of 16S rDNA gene of the isolates SRI-156, -158, -178, -211, -229,
-305 and -360 were matched with Pseudomonas
plecoglossicida, Brevibacterium antiquum, Bacillus altitudinis, Enterobacter ludwigii, E. ludwigii, Acinetobacter tandoii and P. monteilii, respectively in BLAST analysis. This study indicates that the selected bacterial isolates have the potential for PGP and
control of charcoal rot disease in sorghum. 相似文献
10.
A Multiphasic Approach for the Identification of Endophytic Bacterial in Strawberry Fruit and their Potential for Plant Growth Promotion 总被引:1,自引:0,他引:1
de Melo Pereira GV Magalhães KT Lorenzetii ER Souza TP Schwan RF 《Microbial ecology》2012,63(2):405-417
This study used a multiphasic approach, characterized by the simultaneous use of culture-dependent and culture-independent
methods, to investigate endophytic bacterial communities in strawberry (Fragaria ananassa) fruit. A total of 92 bacterial endophytes were isolated and initially grouped by their repetitive extragenic palindromic
(rep)-PCR banding pattern and biochemical features. Phylogenetic analysis of the 16S rRNA gene sequences of 45 representatives
showed that the isolates belonged to the species Bacillus subtilis (eight isolates), Bacillus sp. (seven isolates), Enterobacter sp. (seven isolates), Enterobacter ludwigii (six isolates), Lactobacillus plantarum (six isolates), Pseudomonas sp. (five isolates), Pantoea punctata (three isolates), and Curtobacterium citreum (three isolates). Nucleic acids were extracted from the strawberry fruit and subjected to 16S rRNA gene directed polymerase
chain reaction denaturing gradient gel electrophoresis (16S rRNA PCR-DGGE). The species B. subtilis, Enterobacter sp., and Pseudomonas sp. were detected both by isolation and DGGE. The DGGE fingerprints of total bacterial DNA did not exhibit bands corresponding
to several of the representative species isolated in the extinction dilution (L. plantarum, C. citreum, and P. punctata). In contrast, bands in the DGGE profile that were identified as relatives of Arthrobacter sp. and one uncultivable Erythrobacter sp. were not recovered by cultivation techniques. After isolation, the nitrogen fixation ability and the in vitro production
of indole-3-acetic acid (IAA) equivalents and siderophores were evaluated. A high percentage of isolates were found to possess
the ability to produce siderophores and IAA equivalents; however, only a few isolates belonging to the genera Pseudomonas and Enterobacter showed the ability to fix nitrogen. Plant growth promotion was evaluated under greenhouse conditions and revealed the ability
of the Bacillus strains to enhance the number of leaves, shoot length, root dry weight, and shoot dry weight. The activity of the bacterial
isolate identified as B. subtilis NA-108 exerted the greatest influence on strawberry growth and showed a 42.8% increase in number of leaves, 15.26% for high
shoot, 43.5% increase in root dry weight, and a 77% increase in shoot dry weight when compared with untreated controls. 相似文献
11.
Joshi AA Kanekar PP Kelkar AS Shouche YS Vani AA Borgave SB Sarnaik SS 《Microbial ecology》2008,55(2):163-172
Aerobic, alkaliphilic bacteria were isolated and characterized from water and sediment samples collected in the winter season,
January 2002 from alkaline Lonar lake, India, having pH 10.5. The total number of microorganisms in the sediment and water
samples was found to be 102–106 cfu g−1 and 102–104 cfu ml−1, respectively. One hundred and ninety-six strains were isolated using different enrichment media. To study the bacterial
diversity of Lonar lake and to select the bacterial strains for further characterization, screening was done on the basis
of pH and salt tolerance of the isolates. Sixty-four isolates were subjected to phenotypic, biochemical characterization and
16S rRNA sequencing. Out of 64, 31 bacterial isolates were selected on the basis of their enzyme profile and further subjected
to phylogenetic analysis. Phylogenetic analysis indicated that most of the Lonar lake isolates were related to the phylum
Firmicutes, containing Low G+C, Gram-positive bacteria, with different genera: Bacillus, Paenibacillus, Alkalibacillus, Exiguobacterium, Planococcus, Enterococcus and Vagococcus. Seven strains constituted a Gram-negative bacterial group, with different genera: Halomonas, Stenotrophomonas and Providencia affiliated to γ-Proteobacteria, Alcaligenes to β-Proteobacteria and Paracoccus to α-Proteobacteria. Only five isolates were High G+C, Gram-positive bacteria associated with phylum Actinobacteria, with
various genera: Cellulosimicrobium, Dietzia, Arthrobacter and Micrococcus. Despite the alkaline pH of the Lonar lake, most of the strains were alkalitolerant and only two strains were obligate alkaliphilic.
Most of the isolates produced biotechnologically important enzymes at alkaline pH, while only two isolates (ARI 351 and ARI
341) showed the presence of polyhydroxyalkcanoate (PHA) and exopolysaccharide (EPS), respectively. 相似文献
12.
Electrokinetic remediation and microbial community shift of β-cyclodextrin-dissolved petroleum hydrocarbon-contaminated soil 总被引:1,自引:0,他引:1
Electrokinetic (EK) migration of β-cyclodextrin (β-CD), which is inclusive of total petroleum hydrocarbon (TPH), is an economically
beneficial and environmentally friendly remediation process for oil-contaminated soils. Remediation studies of oil-contaminated
soils generally prepared samples using particular TPHs. This study investigates the removal of TPHs from, and electromigration
of microbial cells in field samples via EK remediation. Both TPH content and soil respiration declined after the EK remediation
process. The strains in the original soil sample included Bacillus sp., Sporosarcina sp., Beta proteobacterium, Streptomyces sp., Pontibacter sp., Azorhizobium sp., Taxeobacter sp., and Williamsia sp. Electromigration of microbial cells reduced the biodiversity of the microbial community in soil following EK remediation.
At 200 V m−1 for 10 days, 36% TPH was removed, with a small population of microbial cells flushed out, demonstrating that EK remediation
is effective for the present oil-contaminated soils collected in field. 相似文献
13.
The bacterial flora of the Oberea linearis (Coleoptera: Cerambycidae) was investigated and 13 different bacteria were isolated from O. linearis larvae. Seven of these bacteria were performed and characterized at species level and the rest of them were characterized
at genus level. In this study, we determined morphological and physiological characteristics of the bacterial isolates by
conventional and routine techniques, biochemical properties and metabolic enzyme profiles by API20E and Phoenix 1000A panel
test systems. Additionally, 16S rRNA gene sequence analysis was also performed to identify the isolates at the molecular level.
The isolates were identified as Acinetobacter calcoaceticus (Ol1), Enterobacter aerogenes (Ol2), Pseudomonas sp. (Ol3), Flavobacterium sp. (Ol4), Microbacterium sp. (Ol5), Enterobacter agglomerans (Ol6), Xanthomonas sp. (Ol7), Pseudomonas syringae (Ol8), Pseudomonas sp. (Ol9), Xanthomonas sp. (Ol10), Enterobacter cancerogenus (Ol11), Xanthomonas maltophilia (Ol12), and Serratia marcescens (Ol13). This is the first record of bacterial isolates (Ol5, Ol8, Ol11, Ol12) from any insect. All these bacteria were tested
against O. linearis larvae, and Serratia marcescens was found to cause the highest mortality (65%). On the other hand, we determined 90% mortality against this pest within four
days by utilizing spore and crystal mixture of Bacillus thuringiensis isolated from Melolontha melolontha. 相似文献
14.
Industries and agriculture activities extensively utilize halogenated compounds. These compounds were found to be toxic and pollute the environment. Thus, many studies have been done on microbial degradation of these chemicals. In this study, an attempt was made to isolate bacterial strains EK1–EK5 from marine sediments collected at Danga Bay and east coast of Singapore island. The 16S rRNA analysis suggested that the isolated bacteria had more than 96% sequence identity to the sequence in the database; therefore, they were designated as Bacillus sp., Rhodococcus sp., Lysinibacillus sp., Microbacterium sp., and Aminobacter sp. The results of molecular analysis were supported by biochemical and microscopic examinations. Bacterial isolates were able to grow slowly in minimal medium containing only 2,2-dichloropropionate as the sole carbon source. The cellular doubling times were 39.60 ± 0.1, 36.60 ± 0.2, 30.71 ± 0.1, 41.23 ± 0.1, and 36.70 ± 0.3 h for EK1, EK2, EK3, EK4, and EK5, respectively. In the future, it will be important to further investigate the presence of the dehalogenase gene in their genomic DNA for further characterization. 相似文献
15.
Poonam Gusain Rashmi Paliwal Vir Singh 《International journal of phytoremediation》2017,19(3):290-299
In search of multitrait plant growth–promoting (PGP) inoculants, we introduced two cadmium-resistant bacterial strains, C4 (PG), C5 (WB), and their consortium C6 (PG × WB) isolated from metal-contaminated industrial waste–fed canal near West Bengal. The test isolates were biochemically characterized and screened in vitro for siderophore production. The infrared spectra revealed the hydroxamate nature of the siderophore produced. Further in green house, siderophore-based seed inoculation with selected PGP isolates exhibited stimulatory effects on seed germination (up to 85.4%), chlorophyll index (22.9 spad unit), shoot and root length (70% and 62.7%), tiller numbers (38.82%), spikelet numbers (52.2%), straw yield (62.2%), grain yield (76.1%), total dry matter of root and shoot (55.56% and 64.4%, respectively), and grain yields (76.1%) of tested wheat cultivars. The 16S rRNA sequencing identified strain PG and WB as Dietzia maris and Lysinibacillus sp. strains. Furthermore, inoculation of C6 (consortium) in both cultivar UP-2565 and KS-227 showed maximum Cd sorption capacity in roots (38.3% and 67.1%) and shoots (68.4% and 67.5%), respectively. Both the strains and their consortium showed a great potential to increase the growth and yield of wheat cultivars, which can also be utilized for rhizoremediation process. 相似文献
16.
V. Sandhya Sk. Z. Ali B. Venkateswarlu Gopal Reddy Minakshi Grover 《Archives of microbiology》2010,192(10):867-876
In this study we isolated and screened drought tolerant Pseudomonas isolates from arid and semi arid crop production systems of India. Five isolates could tolerate osmotic stress up to −0.73 MPa
and possessed multiple PGP properties such as P-solubilization, production of phytohormones (IAA, GA and cytokinin), siderophores,
ammonia and HCN however under osmotic stress expression of PGP traits was low compared to non-stressed conditions. The strains
were identified as Pseudomonas
entomophila, Pseudomonas
stutzeri, Pseudomonas putida, Pseudomonas syringae and Pseudomonas monteilli respectively on the basis of 16S rRNA gene sequence analysis. Osmotic stress affected growth pattern of all the isolates
as indicated by increased mean generation time. An increase level of intracellular free amino acids, proline, total soluble
sugars and exopolysaccharides was observed under osmotic stress suggesting bacterial response to applied stress. Further,
strains GAP-P45 and GRFHYTP52 showing higher levels of EPS and osmolytes (amino acids and proline) accumulation under stress
as compared to non-stress conditions, also exhibited higher expression of PGP traits under stress indicating a relationship
between stress response and expression of PGP traits. We conclude that isolation and screening of indigenous, stress adaptable
strains possessing PGP traits can be a method for selection of efficient stress tolerant PGPR strains. 相似文献
17.
A. V. Sturz 《Plant and Soil》1995,175(2):257-263
Healthy potato tubers (Solanum tuberosum L.) cv. Kennebec were found to be internally colonized by non-pathogenic bacterial populations originating from root zone soil. These endophytic bacteria were categorized, on the basis of bioassays, as plant growth promoting (PGP), plant growth retarding (PGR) and plant growth neutral (PGN). Genera isolated from tubers included Pseudomonas, Bacillus, Xanthomonas, Agrobacterium, Actinomyces and Acinetobacter. The PGP and PGR isolates were similarly distributed throughout these genera. Bacterial populations increased in the root zone soil directly adjacent to the seed piece during and immediately following seed piece decay. Bacteria sampled at this time were capable of promoting tuber number and weight. The proportions of PGP, PGR and PGN bacteria in the root zone were altered as endophytic bacteria were released from the decaying seed piece. The study indicates that endophytic bacteria present in the seed tubers may play an important role in seed piece decay, tuberization and plant growth. 相似文献
18.
Yogesh Kumar Negi Deepti Prabha Satyendra K. Garg J. Kumar 《Journal of Plant Growth Regulation》2011,30(2):128-143
In Uttarakhand, the Organic State of India, where soils in most farming situations are deficient in nutrients and loss of
crops due to soil- and seed-borne pathogens is rampant, use of native plant growth-promoting rhizobacteria (PGPRs) possessing
biocontrol (BC) activities holds promise. In view of this, 600 native cold-tolerant rhizospheric bacterial isolates were collected
from Uttarakhand Himalayas, of which 336 were confirmed as fluorescent Pseudomonas spp. On the basis of specific biochemical tests, these were characterized into three major groups: P. fluorescens (308 isolates), P. aeruginosa (20 isolates), and P. putida (8 isolates). Most of the isolates could grow at 8°C after 12 h of incubation, confirming their cold tolerance. In vitro
biocontrol assays revealed that of 336 isolates, 74 were antagonistic to Rhizoctonia solani and 91 to Fusarium solani, the two major pathogens associated with root-rot complex in vegetables widespread in the region. Simultaneously, good HCN
producers (33 isolates), siderophore producers (80 isolates), and P solubilizers (49 isolates) were also identified, which
could increase the biocontrol and plant growth-promoting efficacies of the putative PGPRs. Among the different species and
biovars, P. fluorescens biovar-I had the maximum number of potential isolates with BC and plant growth-promoting (PGP) activities. In French bean,
under polyhouse and field conditions, five isolates (Pf-173, Pf-193, Pf-547, Pf-551, and Pf-572) showed good BC and PGP activities
as up to 93% reduction in root rot was achieved. A combination of all five isolates was found to be best with respect to BC
and PGP activities. In a set of 59 fluorescent Pseudomonas isolates, RAPD-PCR analysis, using three random oligodecamer primers, revealed high diversity and formed ten distinct clusters,
corresponding to the host of origin (annual or perennial) or habitat (farming situations) of the isolates. The amount of diversity
revealed in the set of fluorescent Pseudomonas isolates could represent enormous diversity that exists in the wild that could be exploited for improved BC and PGP activities
of the PGPRs. For the first time, this study led to a large-scale characterization and repositioning of fluorescent pseudomonads
from the Indian Himalayas. 相似文献
19.
A halotolerantPlanococcus from Antarctic Dry Valley soil 总被引:1,自引:0,他引:1
A halotolerantPlanococcus (strain A4a) was isolated from saline Antarctic Dry Valley soil.Planococcus strain A4a grew over wide ranges of temperature (0°C–40°C) and NaCl concentrations (0–2.0M). When the NaCl concentration of the growth medium was increased, the total intracellular free amino acid concentration increased; however, the intracellular potassium concentration did not increase. This result suggested that intracellular free amino acids functioned as compatible solutes for growth ofPlanococcus strain A4a at elevated NaCl concentrations. The halotolerant and psychrotolerant nature ofPlanococcus strain A4a would appear to provide it with the capacity for growth in the saline Antarctic Dry Valley soil environment from which it was isolated. 相似文献
20.
Barua S Tripathi S Chakraborty A Ghosh S Chakrabarti K 《Indian journal of microbiology》2011,51(3):369-376
The effect of fluctuations of salinity in three different seasons on diazotrophic populations and N2 fixation in six mono cropped rice field soils of the coastal region of the Gangetic delta of West Bengal, India, was studied.
The average pH, ECe, organic carbon and total nitrogen of the soils ranged from 4.99–7.08, 2.02–19.58 dSm−1, 4.68–12.03 g kg−1 and 0.44–1.70 g kg −1, respectively. The average log colony forming units of the bacterial populations and N2-fixation in the soils varied from 4.61 to 5.86 and 2.74 to 4.52 mg N2 fixed 50 ml −1 culture media respectively, with the lowest value recorded in summer. Recovery of microorganisms and N2- fixation gradually decreased with extraneous addition of NaCl in the culture media. All the eight isolates were Gram positive,
spore and capsule formers. They could utilize glucose, sucrose, mannitol, starch, citrate and nitrate, and were catalase and
gelatinase positive, but indole, methyl red and Vogues Proskauer reaction negative. The organisms produced alkaline reaction
on TSI agar slant. The acetylene reduction assay of the isolates at 0 and 1% NaCl in the culture media were 4.51–164.52 and
1.72–100.6 nmole C2H4 ml−1 culture media in 72 h, respectively. The isolates could fix 2.42–4.45 and 2.04–4.08 mg N2 fixed 50 ml−1 culture media at 0 and 1% NaCl in the culture media respectively. 16S rDNA sequences of the isolates were similar to the
species: Bacillus sp. isolate 28A, Bacillus sp. MOLA 87, Bacillus sp. By113 (B)Ydz-dh, Bacillus sp. PN13, Bacillus licheniformis strain RH101, Bacterium Antarctica 14, Bacillus sp. PN13 and Bacillus megaterium. 相似文献