scholarly journals Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Esteban Julián Rubio ◽  
Marcela Susana Montecchia ◽  
Micaela Tosi ◽  
Fabricio Darío Cassán ◽  
Alejandro Perticari ◽  
...  
Keyword(s):  
Phosphate Solubilization ◽  
Agricultural Soils ◽  
Nitrogenase Activity ◽  
Root Hairs ◽  
Siderophore Production ◽  
Phenotypic Characterization ◽  
Rrna Gene ◽  
Wheat Seedlings ◽  
Geographical Regions ◽  
Plant Growth Promoting

The genetic diversity among 31 putativeAzotobacterisolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified asA. chroococcum,A. salinestris, andA. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3) and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2–18.2 μg IAA mL−1, 0.3–0.7 μg GA3 mL−1, and 0.5–1.2 μg Z mL−1. Seed inoculations with further selectedAzotobacterstrains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solutions, but it was not related to bacterial root colonization. Our survey constitutes a first approach to the knowledge ofAzotobacterspecies inhabiting Argentinean soils in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection ofAzotobacterstrains for biofertilizer formulations.

Phosphate solubilization and growth promotion by Pseudomonas fragi CS11RH1 (MTCC 8984), a psychrotolerant bacterium isolated from a high altitude Himalayan rhizosphere

Biologia ◽  
2009 ◽  
Vol 64 (2) ◽  
Author(s):  
Govindan Selvakumar ◽  
Piyush Joshi ◽  
Sehar Nazim ◽  
Pankaj Mishra ◽  
Jaideep Bisht ◽  
...  
Keyword(s):  
High Altitude ◽  
Phosphate Solubilization ◽  
Plant Biomass ◽  
Growth Promotion ◽  
Early Report ◽  
Rrna Gene ◽  
Pseudomonas Fragi ◽  
Wheat Seedlings ◽  
Cold Temperatures ◽  
Psychrotolerant Bacterium

AbstractPhosphate solubilization and growth promotion by Pseudomonas fragi CS11RH1 (MTCC 8984), a psychrotolerant bacterium isolated from a high altitude garlic rhizosphere from the Indian Himalayas, are reported here. The identity of the isolate was arrived on the basis of its biochemical features and sequencing of the 16S rRNA gene. The isolate grew and solubilized phosphate at temperatures ranging from 4 to 30°C. Besides solubilizing P it produced indole acetic acid (IAA) and hydrogen cyanide (HCN). Seed bacterization with the isolate significantly increased the percent germination, rate of germination, plant biomass and nutrient uptake of wheat seedlings. While Pseudomonas fragi is normally associated with the spoilage of dairy products stored at cold temperatures, this is an early report on the plant growth promoting ability of the bacterium.

scholarly journals Bacteria Isolated from Wastewater Irrigated Agricultural Soils Adapt to Heavy Metal Toxicity While Maintaining Their Plant Growth Promoting Traits

2021 ◽  
Vol 13 (14) ◽  
pp. 7792
Author(s):  
Abdul Wahab Ajmal ◽  
Saleha Saroosh ◽  
Shah Mulk ◽  
Muhammad Nadeem Hassan ◽  
Humaira Yasmin ◽  
...  
Keyword(s):  
Plant Growth ◽  
Agricultural Soils ◽  
Culture Media ◽  
Growth Promotion ◽  
Metal Resistance ◽  
Rrna Gene ◽  
Gene Sequence Analysis ◽  
Plant Growth Promoting ◽  
Growth Promoting

The present study explored the plant growth promotion and bioremediation potential of bacteria inhabiting wastewater irrigated agricultural soils. Thirty out of 75 bacterial isolates (40%), 29/75 (39%) and 28/75 (37%) solubilized Zn, K and PO4 during plate essays respectively. Fifty-six percent of the isolates produced siderophores, while 30% released protease in vitro. Seventy-four percent of bacteria resisted Pb, Ni and Cd at various concentrations added to the culture media plates. Sixteen out of 75 (26%) isolates were able to fix N in Nbf medium. Among these 16 N fixers, N fixing nifH, nifD and nifK genes was detected through PCR in 8, 7 and 1 strain respectively using gene specific primers designed in the study with Enterobacter sp. having all three (nifHKD) genes. Isolated bacteria showed resemblance to diverse genera such as Bacillus, Pseudomonas, Enterobacter, Citrobacter, Acinetobacter, Serratia, Klebsiella and Enterococcus based on 16S rRNA gene sequence analysis. In addition to showing the best mineral solubilization and metal resistance potential, Citrobacter sp. and Enterobacter sp. also removed 87%, 79% and 43% and 86%, 78% and 51% of Ni, Cd and Pb, respectively, from aqueous solution. These potent bacteria may be exploited both for bioremediation and biofertilization of wastewater irrigated soils leading to sustainable agriculture.

scholarly journals Isolation and Characterization of Plant Growth Promoting Rhizobacteria (PGPR) from Rice Rhizosphere of Varanasi and East Champaran District of India

2014 ◽  
Vol 3 ◽  
pp. 81-90 ◽  
Author(s):  
Umesh Prasad Shrivastava
Keyword(s):  
Nitrogenase Activity ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Siderophore Production ◽  
Iaa Production ◽  
P Solubilization ◽  
Isolation And Characterization ◽  
Solid Agar ◽  
Plant Growth Promoting ◽  
Enrichment Techniques

Keeping with objective to search efficient PGPR isolates, 46 bacterial isolates were isolated from the rhizosphere of 17 rice fields of two districts of India employing standard enrichment techniques using  JNFb- solid agar medium. Among all isolates, ECI-10A showed highest nitrogenase activity (1.72 ± 0.09 mmol C2H4 formed/mg protein/h) and ECI-2A showed lowest activity (0.62 ± 0.08 mmol C2H4 formed/mg protein/h). IAA production, P-solubilization and siderophore production were also tested among these isolates. Highest  IAA production, P-solubilization and siderophore production were recorded in AF-7C (7.36 ± 0.38 µg/mg dry weight), ECI-12A (188.65 ± 8.65 µg/mg dry weight) and ECI-10B (20.43 ± 3.94 μg/ mg dry weight) respectively; whereas, lowest in AF-4B (2.3 ± 0.3 µg/mg dry weight),  AF-1C (12.47 ± 3.5µg/mg dry weight) and AF-4B (1.45 ± 2.32 μg/ mg dry weight) respectively. Pseudomonas, Klebsiella, Azotobacter and Agrobacterium were predominantly present in the rhizosphere of rice plants of both districts of India is reported in present investigation.Academic Voices, Vol. 3, No. 1, 2013, Pages 81-90   DOI: http://dx.doi.org/10.3126/av.v3i1.9542 

scholarly journals Isolation and Characterization of Phosphate Solubilizing Diazotrophic Bacteria from Rhizosphere of Rice Plant of Indo-Nepal Border

2016 ◽  
Vol 5 ◽  
pp. 79-87
Author(s):  
Umesh Prasad Shrivastava
Keyword(s):  
Rice Plant ◽  
Phosphate Solubilization ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Rrna Gene ◽  
Isolation And Characterization ◽  
Query Coverage ◽  
Plant Growth Promoting ◽  
Phosphate Solubilizing ◽  
Bacterial Characterization

Free-living nitrogen fixing bacteria were isolated from the rhizosphere of rice plant of different regions of Indo-Nepal border. 33.78% isolates among them showed mineral phosphate solubilization. On the basis of bacterial characterization and identification with Bergey’s manual of Determinative Bacteriology (Holt et al, 1994), 38% isolates showed maximum similarity with Pseudomonas and Azotobacter, 30% with members of Enterobacteriaceae, 4% with Gram’s positive Microbacterium sp. and 28% was categorized unknown. ECI 12A isolate showed maximum solubilization index (S.I.), 0.809 on solid medium whereas 188.65 mg P/mg dry weight phosphate solubilization in liquid medium. The highest phosphate solubilizing isolate ECI 12A was sequenced after amplification of partial 16S rRNA gene, blast with BLASTn 2.2.17 program of NCBI showed 99 % identity having 99 % query coverage with Microbacterium sp. This isolate has been named as Microbacterium sp. Strain ECI-12A.The sequence of this strain has been deposited in NCBI Gene Bank under accession number EU155122 and this strain has promising potential for developing as a plant growth promoting rhizobacteria (PGPR) as well as biofertilizer.Academic Voices Vol.5 2015: 79-87

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

scholarly journals Remodeling of root morphology by CuO and ZnO nanoparticles: effects on drought tolerance for plants colonized by a beneficial pseudomonad

Botany ◽  
2018 ◽  
Vol 96 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Kwang-Yeol Yang ◽  
Stephanie Doxey ◽  
Joan E. McLean ◽  
David Britt ◽  
Andre Watson ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Root Hairs ◽  
Triticum Aestivum L ◽  
Metal Stress ◽  
Root Tip ◽  
Zno Nps ◽  
Wheat Seedlings ◽  
Cuo Nps ◽  
Expression Of Genes ◽  
Induced Tolerance

Formulations that include nanoparticles of CuO and ZnO are being considered for agricultural applications as fertilizers because they act as sources of Cu or Zn. Currently, few studies of the effects of these nanoparticles (NPs) consider the three-way interactions of NPs with the plant plus its microbiome. At doses that produced root shortening by both nanoparticles (NPs), CuO NPs induced the proliferation of elongated root hairs close to the root tip, and ZnO NPs increased lateral root formation in wheat seedlings (Triticum aestivum L.). These responses occurred with roots colonized by a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6), originally isolated from roots of wheat grown under dryland farming in calcareous soils. The PcO6-induced tolerance to drought stress in wheat seedlings was not impaired by the NPs. Rather, growth of the PcO6-colonized plants with NPs resulted in systemic increases in the expression of genes associated with tolerance to water stress. Increased expression in the shoots of other genes related to metal stress was consistent with higher levels of Cu and Zn in PcO6-colonized shoots grown with the NPs. This work demonstrates that plants grown with CuO or ZnO NPs showed cross-protection from different challenges such as metal stress and drought.

scholarly journals A prospectus of plant growth promoting endophytic bacterium from orchid (Vanda cristata)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sujit Shah ◽  
Krishna Chand ◽  
Bhagwan Rekadwad ◽  
Yogesh S. Shouche ◽  
Jyotsna Sharma ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Endophytic Bacterium ◽  
Epifluorescence Microscopy ◽  
In Vitro Cultivation ◽  
Rrna Gene ◽  
Bacillus Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Background A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability. Results Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level. Conclusions Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.

scholarly journals Genomic characterization and computational phenotyping of nitrogen-fixing bacteria isolated from Colombian sugarcane fields

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luz K. Medina-Cordoba ◽  
Aroon T. Chande ◽  
Lavanya Rishishwar ◽  
Leonard W. Mayer ◽  
Lina C. Valderrama-Aguirre ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Nitrogen Fixation ◽  
Plant Growth ◽  
Phosphate Solubilization ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Promising Tool ◽  
A Genome ◽  
Plant Growth Promoting ◽  
Growth Promoting

AbstractPrevious studies have shown the sugarcane microbiome harbors diverse plant growth promoting microorganisms, including nitrogen-fixing bacteria (diazotrophs), which can serve as biofertilizers. The genomes of 22 diazotrophs from Colombian sugarcane fields were sequenced to investigate potential biofertilizers. A genome-enabled computational phenotyping approach was developed to prioritize sugarcane associated diazotrophs according to their potential as biofertilizers. This method selects isolates that have potential for nitrogen fixation and other plant growth promoting (PGP) phenotypes while showing low risk for virulence and antibiotic resistance. Intact nitrogenase (nif) genes and operons were found in 18 of the isolates. Isolates also encode phosphate solubilization and siderophore production operons, and other PGP genes. The majority of sugarcane isolates showed uniformly low predicted virulence and antibiotic resistance compared to clinical isolates. Six strains with the highest overall genotype scores were experimentally evaluated for nitrogen fixation, phosphate solubilization, and the production of siderophores, gibberellic acid, and indole acetic acid. Results from the biochemical assays were consistent and validated computational phenotype predictions. A genotypic and phenotypic threshold was observed that separated strains by their potential for PGP versus predicted pathogenicity. Our results indicate that computational phenotyping is a promising tool for the assessment of bacteria detected in agricultural ecosystems.

scholarly journals Umboniibacter marinipuniceus gen. nov., sp. nov., a marine gammaproteobacterium isolated from the mollusc Umbonium costatum from the Sea of Japan

2010 ◽  
Vol 60 (3) ◽  
pp. 603-609 ◽  
Author(s):  
Lyudmila A. Romanenko ◽  
Naoto Tanaka ◽  
Galina M. Frolova
Keyword(s):  
Sea Of Japan ◽  
Sequence Similarity ◽  
Fatty Acid Analysis ◽  
Phenotypic Characterization ◽  
The Sea Of Japan ◽  
Rrna Gene ◽  
Phylogenetic Distance ◽  
The Novel ◽  
Bacterial Strains ◽  
Separate Branch

Two bacterial strains, KMM 3891T and KMM 3892, were isolated from internal tissues of the marine mollusc Umbonium costatum collected from the Sea of Japan. The novel isolates were Gram-negative, aerobic, faint pink–reddish-pigmented, rod-shaped, non-motile, stenohaline and psychrotolerant bacteria that were unable to degrade most tested complex polysaccharides. Polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Fatty acid analysis revealed C17 : 1 ω6c, C17 : 0, C16 : 0 and C16 : 1 ω7c as the dominant components. The major isoprenoid quinone was Q-7. The DNA G+C content of strain KMM 3891T was 51.7 mol%. According to phylogenetic analysis of 16S rRNA gene sequences, strains KMM 3891T and KMM 3892 were positioned within the Gammaproteobacteria as a separate branch, sharing <93 % sequence similarity to their phylogenetic relatives including Saccharophagus degradans, Microbulbifer species, Endozoicomonas elysicola, Simiduia agarivorans and Teredinibacter turnerae. Based on phenotypic characterization and phylogenetic distance, the novel marine isolates KMM 3891T and KMM 3892 represent a new genus and species, for which the name Umboniibacter marinipuniceus gen. nov., sp. nov. is proposed. The type strain of Umboniibacter marinipuniceus is KMM 3891T (=NRIC 0753T =JCM 15738T).

scholarly journals Rhizobium oryzicola sp. nov., potential plant-growth-promoting endophytic bacteria isolated from rice roots

2015 ◽  
Vol 65 (Pt_9) ◽  
pp. 2931-2936 ◽  
Author(s):  
Xiao-Xia Zhang ◽  
Ju-Sheng Gao ◽  
Yan-Hua Cao ◽  
Rizwan Ali Sheirdil ◽  
Xiu-Cheng Wang ◽  
...  
Keyword(s):  
Type Strain ◽  
Housekeeping Genes ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Astragalus Sinicus ◽  
Dna Relatedness ◽  
Rice Roots ◽  
Long Term Experiment ◽  
Plant Growth Promoting

Bacterial strains ZYY136T and ZYY9 were isolated from surface-sterilized rice roots from a long-term experiment of rice–rice–Astragalus sinicus rotation. The 16S rRNA gene sequences of strains ZYY136T and ZYY9 showed the highest similarity, of 97.0  %, to Rhizobium tarimense PL-41T. Sequence analysis of the housekeeping genes recA, thrC and atpD clearly differentiated the isolates from currently described species of the genus Rhizobium. The DNA–DNA relatedness value between ZYY136T and ZYY9 was 82.3  %, and ZYY136T showed 34.0  % DNA–DNA relatedness with the most closely related type strain, R. tarimense PL-41T. The DNA G+C content of strain ZYY136T was 58.1 mol%. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and C16 : 0 3-OH. Strains ZYY136T and ZYY9 could be differentiated from the previously defined species of the genus Rhizobium by several phenotypic characteristics. Therefore, we conclude that strains ZYY136T and ZYY9 represent a novel species of the genus Rhizobium, for which the name Rhizobium oryzicola sp. nov. is proposed (type strain ZYY136T = ACCC 05753T = KCTC 32088T).

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