scholarly journals Mechanism of phosphate solubilization and antifungal activity of Streptomyces spp. isolated from wheat roots and rhizosphere and their application in improving plant growth

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 778-788 ◽  
Author(s):  
Rahul Jog ◽  
Maharshi Pandya ◽  
G. Nareshkumar ◽  
Shalini Rajkumar
Keyword(s):  
Gene Expression ◽  
Antifungal Activity ◽  
Plant Growth ◽  
Potential Field ◽  
Phosphate Solubilization ◽  
Isocitrate Lyase ◽  
Malate Synthase ◽  
Plant Growth Promoting Activities ◽  
Plant Growth Promoting ◽  
Growth Promoting

The application of plant-growth-promoting rhizobacteria (PGPR) at field scale has been hindered by an inadequate understanding of the mechanisms that enhance plant growth, rhizosphere incompetence and the inability of bacterial strains to thrive in different soil types and environmental conditions. Actinobacteria with their sporulation, nutrient cycling, root colonization, bio-control and other plant-growth-promoting activities could be potential field bio-inoculants. We report the isolation of five rhizospheric and two root endophytic actinobacteria from Triticum aestivum (wheat) plants. The cultures exhibited plant-growth-promoting activities, namely phosphate solubilization (1916 mg l−1), phytase (0.68 U ml−1), chitinase (6.2 U ml−1), indole-3-acetic acid (136.5 mg l−1) and siderophore (47.4 mg l−1) production, as well as utilizing all the rhizospheric sugars under test. Malate (50–55 mmol l−1) was estimated in the culture supernatant of the highest phosphate solublizer, Streptomyces mhcr0816. The mechanism of malate overproduction was studied by gene expression and assays of key glyoxalate cycle enzymes – isocitrate dehydrogenase (IDH), isocitrate lyase (ICL) and malate synthase (MS). The significant increase in gene expression (ICL fourfold, MS sixfold) and enzyme activity (ICL fourfold, MS tenfold) of ICL and MS during stationary phase resulted in malate production as indicated by lowered pH (2.9) and HPLC analysis (retention time 13.1 min). Similarly, the secondary metabolites for chitinase-independent biocontrol activity of Streptomyces mhcr0817, as identified by GC-MS and 1H-NMR spectra, were isoforms of pyrrole derivatives. The inoculation of actinobacterial isolate mhce0811 in T. aestivum (wheat) significantly improved plant growth, biomass (33 %) and mineral (Fe, Mn, P) content in non-axenic conditions. Thus the actinobacterial isolates reported here were efficient PGPR possessing significant antifungal activity and may have potential field applications.

scholarly journals Evaluation of Phytase Producing Bacteria for Their Plant Growth Promoting Activities

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Singh ◽  
Vinod Kumar ◽  
Sanjeev Agrawal
Keyword(s):  
Plant Growth ◽  
Phosphate Solubilization ◽  
Growth Promotion ◽  
Growth Parameters ◽  
Growth Effect ◽  
Bacterial Isolates ◽  
Iaa Production ◽  
Plant Growth Promoting Activities ◽  
Plant Growth Promoting ◽  
Growth Promoting

Bacterial inoculants are known to possess plant growth promoting abilities and have potential as liquid biofertilizer application. Four phytase producing bacterial isolates (phytase activity in the range of 0.076–0.174 U/mL), identified asAdvenellaspecies (PB-05, PB-06, and PB-10) andCellulosimicrobiumsp. PB-09, were analyzed for their plant growth promoting activities like siderophore production, IAA production, HCN production, ammonia production, phosphate solubilization, and antifungal activity. All isolates were positive for the above characteristics except for HCN production. The solubilization index for phosphorus on Pikovskaya agar plates was in the range of 2–4. Significant amount of IAA (7.19 to 35.03 μg/mL) production and solubilized phosphate (189.53 to 746.84 μg/mL) was noticed by these isolates at different time intervals. Besides that, a greenhouse study was also conducted with Indian mustard to evaluate the potential of these isolates to promote plant growth. Effect of seed bacterization on various plant growth parameters and P uptake by plant were used as indicators. The plant growth promoting ability of bacterial isolates in pot experiments was correlated to IAA production, phosphate solubilization, and otherin vitrotests. On the basis of present findings, isolate PB-06 was most promising in plant growth promotion with multiple growth promoting characteristics.

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.

Phosphate-solubilizing peanut associated bacteria: screening for plant growth-promoting activities

2009 ◽  
Vol 329 (1-2) ◽  
pp. 421-431 ◽  
Author(s):  
Tania Taurian ◽  
María Soledad Anzuay ◽  
Jorge Guillermo Angelini ◽  
María Laura Tonelli ◽  
Liliana Ludueña ◽  
...  
Keyword(s):  
Plant Growth ◽  
Associated Bacteria ◽  
Plant Growth Promoting Activities ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phosphate Solubilizing

scholarly journals Diversity, biocontrol, and growth promotion potential of culturable endophytic fungi isolated from root, shoot, and leaf of wild Phoebe bournei (Hemsl.) Yang across the seasons

2021 ◽  
Author(s):  
Cun Yu ◽  
Ying Yao
Keyword(s):  
Plant Growth ◽  
Endophytic Fungi ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Leaf Spot Disease ◽  
Plant Growth Promoting Activities ◽  
Potential Applicability ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phoebe Bournei

Endophytic fungi were isolated from Phoebe bournei and their diversity and antimicrobial and plant growth-promoting activities were investigated. Of the 389 isolated endophytic fungi, 88.90% belonged to phylum Ascomycota and 11.10% to phylum Basidiomycota. The isolates were grouped into four taxonomic classes, 11 orders, 30 genera, and 45 species based on internal transcribed spacer sequencing and morphologic analysis. The host showed a strong affinity for the genera Diaporthe and Phyllosticta. The diversity of the fungi was highest in autumn, followed by spring and summer, and was lowest in winter. The fungi exhibited notable tissue specificity in P. bournei, and the species richness and diversity were highest in the root across all seasons. Five isolates showed antimicrobial activity against eight plant pathogens, and reduced the incidence of leaf spot disease in P. bournei. Additionally, 9 biocontrol isolates showed plant growth-promoting activity, with five significantly promoting P. bournei seedling growth. This is the first report on the endophytic fungi of P. bournei and their potential applicability to plant disease control and growth promotion.

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