scholarly journals Pseudomonas fluorescens Pf7: A Potential Biocontrol Agent against Aspergillus flavus Induced Aflatoxin Contamination in Groundnut

2019 ◽  
pp. 1-7 ◽  
Author(s):  
M. Ravi Teja ◽  
K. Vijay Krishna Kumar ◽  
H. Sudini
Keyword(s):  
Plant Growth ◽  
Aspergillus Flavus ◽  
Plant Growth Promoting Rhizobacteria ◽  
Aflatoxin Contamination ◽  
Dual Culture ◽  
Arachis Hypogaea L ◽  
Potential Biocontrol Agent ◽  
Plant Growth Promoting ◽  
Growth Promoting

Aflatoxin contamination is a qualitative problem in groundnut (Arachis hypogaea L.) occurring at both pre-and post-harvest stages. These aflatoxins are secondary metabolites produced by Aspergillus flavus and A. parasiticus and have carcinogenic, hepatotoxic, teratogenic and immuno-suppressive effects. Use of plant growth-promoting rhizobacteria (PGPR) is a viable and sustainable option in managing aflatoxin problem in groundnut. Our present study is aimed at identifying a plant growth-promoting rhizobacteria (PGPR) strain with superior antagonistic abilities on A. flavus infection, aflatoxin contamination and to determine its mode of action. Ten native P. fluorescens isolates were isolated from groundnut rhizosphere and screened against A. flavus by dual culture and in vitro seed colonization (IVSC) assays. In dual culture and IVSC studies, Pf7 exhibited higher degree of antagonism on A. flavus (54% inhibition), inhibited its colonization and reduced aflatoxin contamination (27.8 µg kg-1) in kernels.

scholarly journals In vitro and in planta antagonistic effects of plant growth-promoting rhizobacteria consortium against soilborne plant pathogens of Solanum tuberosum and Solanum lycopersicum

2020 ◽  
Vol 367 (13) ◽  
Author(s):  
Marika Pellegrini ◽  
Claudia Ercole ◽  
Chiara Di Zio ◽  
Federica Matteucci ◽  
Loretta Pace ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Plant Growth ◽  
Solanum Lycopersicum ◽  
Plant Pathogens ◽  
Solanum Tuberosum L ◽  
Plant Growth Promoting Rhizobacteria ◽  
Dual Culture ◽  
Plant Growth Promoting ◽  
Growth Promoting

ABSTRACT Potatoes (Solanum tuberosum L.) and tomatoes (Solanum lycopersicum L.), among the main crops belonging to the Solanaceae family, are attacked by several pathogens. Among them Fusarium oxysporum f. sp. radicis-lycopersici and Rhizoctonia solani are very common and cause significant losses. Four plant growth-promoting rhizobacteria, Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae and Burkholderia ambifaria were tested against these pathogens. In vitro antagonistic activities of single strains were assessed through dual culture plates. Strains showing antagonistic activity (G. diazotrophicus, H. seropedicae and B. ambifaria) were combined and, after an in vitro confirmation, the consortium was applied on S. lycopersicum and S. tuberosum in a greenhouse pot experiment. The bioprotection was assessed in pre-emergence (infection before germination) and post-emergence (infection after germination). The consortium was able to successfully counteract the infection of both F. oxysporum and R. solani, allowing a regular development of plants. The biocontrol of the fungal pathogens was highlighted both in pre-emergence and post-emergence conditions. This selected consortium could be a valid alternative to agrochemicals and could be exploited as biocontrol agent to counteract losses due to these pathogenic fungi.

scholarly journals Plant Growth Promotion and Biocontrol Properties of Aneurinibacillus migulanus Isolated from Maize Roots (Zea mays)

2021 ◽  
pp. 46-59
Author(s):  
Lynda Kelvin Asogwa ◽  
Frank C. Ogbo
Keyword(s):  
Zea Mays ◽  
Plant Growth ◽  
Plant Height ◽  
Pot Experiment ◽  
Root Weight ◽  
Dual Culture ◽  
Maize Roots ◽  
Plant Growth Promoting ◽  
Growth Promoting

Aims: To isolate Plant Growth Promoting Bacillus strain from maize roots, to evaluate its biocontrol potentials and to characterize the isolate using16S rRNA sequencing. Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Awka, between February 2019 and March 2020. Methodology: The isolation of Plant Growth Promoting Rhizobacteria (PGPR) from maize roots was done using Pikovskaya (PVK) agar. Quantitative determination of phosphate was carried out using PVK broth. Evaluations of other plant growth promoting properties were carried out such as IAA, etc. Fusarium and Enterobacter plant pathogens were isolated from diseased maize plants. The in vitro antagonism effects of the PGPR isolates against the pathogens were analyzed using the dual culture plate technique. The pot experiment was carried out in a completely randomized design. Plant characteristics such as plant height, shoot  and root weight, chlorophyll content, as well as disease assessment were recorded accordingly. The organisms were identified using phenotypic and molecular methods. Results: Seven PGPR bacteria were isolated from maize (Zea mays) roots using PVK agar. Aneurinibacillus migulanus gave the highest solubilization index of 4.21 while isolate IS48 gave the lowest solubilization index of 1.47. A. migulanus produced IAA, ammonia and cellulase enzyme but no hydrogen cyanide. The organism showed antagonism activity against the two tested phytopathogens. In the pot experiment, A. migulanus treated plants showed a statistically insignificant difference in maize plant height at P=0.05 but gave significant increases in shoot and root wet weights. The organism offered 83.33% and 71.43% protection against Enterobacter and Fusarium pathogens respectively in the pot experiment. Conclusion: A. migulanus solubilized phosphate in addition to other plant growth promoting  properties. It showed biocontrol potentials both in vitro and in vivo and thus can be used as substitute for synthetic agrochemicals.

scholarly journals Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae

2019 ◽  
Vol 20 (12) ◽  
Author(s):  
Haliatur Rahma ◽  
NURBAILIS ◽  
NILA KRISTINA
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Rice Seedling ◽  
Xanthomonas Oryzae ◽  
Resistant Variety ◽  
Dual Culture ◽  
Rice Seedlings ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract. Rahma H, Nurbailis, Kristina N. 2019. Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae. Biodiversitas 20: 3654-3661. Xanthomonas oryzae pv. oryzae (Xoo), a major limiting factor in rice production, and the use of resistant Xoo varieties have failed to control the bacterial pathogens as well as increased yield. It is due to the diversity in pathotypes, caused by environmental factors, the nature of resistant variety used, and gene mutation. The aims of this study were to select rhizobacterial strains with the potential of suppressing Xoo growth and promoting the growth of rice seedlings. This experiment was conducted in a completely randomized design (CRD) using seven rhizobacterial isolates selected through a dual culture test, with four replications. There were four isolates that potential in inhibiting the growth of Xoo, namely KJKB5.4, LMTSA5.4, Bacillus cereus AJ34, and Alcaligenes faecalis AJ14, with inhibition diameters greater than 11.50 mm. Rhizobacterial supernatant of 4 potential isolates has a zone of inhibition ranging from 12.25 to 24.00 mm. Four potential isolates were also able to solubilize phosphate, produce indole acetic acid (IAA) growth hormone, and siderophore, as well as enhance the growth of rice seedlings. Based on the nucleic acid sequencing of LMTSA5.4, KJKB5.4, and RK12 isolates were identified as Stenotrophomonas malthopilia strain LMG 958 (99.13%) accession NR 119220.1, Stenotrophomonas pavanii strain LMG 25348 (95.84%) accession NR 118008.1 and Ochrobactrum ciceri strain ca-34 (92.91%) accession NR115819.1.

scholarly journals Integrated Genomic and Greenhouse Assessment of a Novel Plant Growth-Promoting Rhizobacterium for Tomato Plant

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria Chiara Guerrieri ◽  
Andrea Fiorini ◽  
Elisabetta Fanfoni ◽  
Vincenzo Tabaglio ◽  
Pier Sandro Cocconcelli ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Nutrition ◽  
Growth Regulation ◽  
Root Length Density ◽  
Plant Growth Promoting Rhizobacteria ◽  
Conventional Management ◽  
Tomato Field ◽  
Plant Growth Promoting ◽  
Growth Promoting

Plant growth promoting rhizobacteria (PGPR) can display several plant-beneficial properties, including support to plant nutrition, regulation of plant growth, and biocontrol of pests. Mechanisms behind these effects are directly related to the presence and expression of specific genes, and different PGPR strains can be differentiated by the presence of different genes. In this study we reported a comprehensive evaluation of a novel PGPR Klebsiella variicola UC4115 from the field to the lab, and from the lab to the plant. The isolate from tomato field was screened in-vitro for different activities related to plant nutrition and growth regulation as well as for antifungal traits. We performed a functional annotation of genes contributing to plant-beneficial functions previously tested in-vitro. Furthermore, the in-vitro characterization, the whole genome sequencing and annotation of K. variicola UC4115, were compared with the well-known PGPR Azospirillum brasilense strain Sp7. This novel comparative analysis revealed different accumulation of plant-beneficial functions contributing genes, and the presence of different genes that accomplished the same functions. Greenhouse assays on tomato seedlings from BBCH 11–12 to BBCH > 14 were performed under either organic or conventional management. In each of them, three PGPR inoculations (control, K. variicola UC4115, A. brasilense Sp7) were applied at either seed-, root-, and seed plus root level. Results confirmed the PGP potential of K. variicola UC4115; in particular, its high value potential as indole-3-acetic acid producer was observed in increasing of root length density and diameter class length parameters. While, in general, A. brasilense Sp7 had a greater effect on biomass, probably due to its high ability as nitrogen-fixing bacteria. For K. variicola UC4115, the most consistent data were noticed under organic management, with application at seed level. While, A. brasilense Sp7 showed the greatest performance under conventional management. Our data highlight the necessity to tailor the selected PGPR, with the mode of inoculation and the crop-soil combination.

scholarly journals Evaluation of diverse range microbes for their plant growth promoting abilities and their pesticide compatibility

2021 ◽  
pp. 47-58
Author(s):  
Tulja Sanam ◽  
S. Triveni ◽  
J. Satyanaryana ◽  
Sridhar Goud Nerella ◽  
K. Damodara Chari ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Atomic Absorption Spectrophotometry ◽  
In Vitro Assays ◽  
Bacterial Isolates ◽  
Diverse Range ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Bacillus Isolate

Plant growth-promoting rhizobacteria (PGPR) contribute to an increase in crop yield through an environmentally friendly method, therefore eight rhizospheric bacteria, two of each genera Bacillus, Pseudomonas, Azotobacter and Azospirillum were examined for their efficacy to solubilize mineral nutrients using atomic absorption spectrophotometry and a flame photometer. Their potency to produce phytohormones, synthesis biocontrol components and their compatibility with pesticides using in vitro assays was studied. All of the chosen bacterial isolates proved positive for the above-mentioned Plant Growth Promoting traits. Among the eight bacterial isolates Pseudomonas isolate P69 showed the highest phosphorous solubilization efficiency of 190.91 % and another isolate P48 produced a maximum of 27.63µg mL-1 of gibberellic acid, Bacillus isolate B120 could solubilize maximum amount of ZnO and ZnCO3 accounting for 21.3ppm and 25.9ppm, respectively, not merely in terms of solubilization when compared to the other isolates, B120 produced the highest levels of HCN (77.33 ppm TCC) and siderophores (48.87psu). On day 9 after inoculation, Azotobacter isolate AZB17 performed effectively in potassium solubilization of 6.25g mL-1 with a pH drop to 3.83. The Azospirillum isolate ASP25 outperformed all other isolates in terms of IAA production (22.64g mL-1) and Bacillus isolate B365 was found to be more compatible with eight different pesticides used in the field at varying concentrations. All of these factors point to the possibility of using these bacterial isolates B120, P48, P69, AZB17, and ASP25 as biofertilizers in sustainable agriculture.

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