scholarly journals Evaluation of antagonistic activities against Pythium myriotylum and plant growth promoting traits of Streptomyces isolated from Cocoyam (Xanthosoma sagittifolium (L.) Schott) rhizosphere

2019 ◽  
pp. 920-933
Author(s):  
Peguy Flora Djuidje Kouomou ◽  
Cécile Annie Ewane ◽  
Sylvain Lerat ◽  
Denis Omokolo Ndoumou ◽  
Carole Beaulieu ◽  
...  
Keyword(s):  
16S Rrna ◽  
Plant Growth ◽  
Dual Culture ◽  
In Vitro Production ◽  
Pythium Myriotylum ◽  
Pgp Traits ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Vitro Production

The focus of this study was to isolate, evaluate and characterize cocoyam rhizospheric actinobacteria collected from Mount Cameroon for their potential antagonistic activities against Pythium myriotylum, the causative agent of cocoyam root rot disease, and/or their ability to promote plant growth. Actinobacteria were isolated from soil samples by using serial dilution method. Dual culture assay was used to screen the isolates against fungal phytopathogens including P. myriotylum. The selected isolates were characterized morphologically, physiologically, biochemically and genetically. Furthermore, these isolates were subjected to in vitro production of various plant growth promoting (PGP) traits. Among the 287 isolates distributed into 12 distinct groups, PFK4, PFBOT7 and PFEL2 had high antagonistic effects against P. myriotylum and they were regarded as promising candidates for further study of their biocontrol ability. The identification of actinobacterial isolates was done using universal PCR of partial 16S rRNA sequences combined with bioinformatics and phylogenetic procedures. The results revealed that all these isolates belong to the genus Streptomyces spp. The isolate PFK4 showed 99% similarity with Streptomyces albulus while PFBOT7 showed 99% similarity with Streptomyces albus and PFEL2 showed 98% similarity with Streptomyces gandoceansis based on their 16S rRNA gene sequences. In this study for the first time, we report S. gandocaensis strain for the biological control of Pythium myriotylum. The role of these isolates in Plant Growth Promotion (PGP) by in vitro production of PGP traits such as phosphate solubilisation, siderophore, indole-3-acetic acid (IAA), ACC deaminase and cell wall degrading enzymes production were also evaluated and showed as potential PGP agents. Concurrent production of PGP substances coupled with broad spectrum of antifungal and antibacterial activities of these three strains suggest their potential use as promising biocontrol and PGP tools for the development of an alternative control method for cocoyam cultivation.

scholarly journals Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

2021 ◽  
Vol 9 (8) ◽  
pp. 1588
Author(s):  
Anastasia Venieraki ◽  
Styliani N. Chorianopoulou ◽  
Panagiotis Katinakis ◽  
Dimitris L. Bouranis
Keyword(s):  
Plant Growth ◽  
Salinity Stress ◽  
Calcareous Soil ◽  
In Vitro Studies ◽  
Pgp Traits ◽  
Biocontrol Activity ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Microbial Fertilizers

Plant growth promoting rhizobacteria (PGPR) can be functional microbial fertilizers and/or biological control agents, contributing to an eco-spirit and safe solution for chemical replacement. Therefore, we have isolated rhizospheric arylsulfatase (ARS)-producing bacteria, belonging to Pseudomonas and Bacillus genus, from durum wheat crop grown on calcareous soil. These isolates harbouring plant growth promoting (PGP) traits were further evaluated in vitro for additional PGP traits, including indole compounds production and biocontrol activity against phytopathogens, limiting the group of multi-trait strains to eight. The selected bacterial strains were further evaluated for PGP attributes associated with biofilm formation, compatibility, salt tolerance ability and effect on plant growth. In vitro studies demonstrated that the multi-trait isolates, Bacillus (1.SG.7, 5.SG.3) and Pseudomonas (2.SG.20, 2.C.19) strains, enhanced the lateral roots abundance and shoots biomass, mitigated salinity stress, suggesting the utility of beneficial ARS-producing bacteria as potential microbial fertilizers. Furthermore, in vitro studies demonstrated that compatible combinations of multi-trait isolates, Bacillus sp. 1.SG.7 in a mixture coupled with 5.SG.3, and 2.C.19 with 5.SG.3 belonging to Bacillus and Pseudomonas, respectively, may enhance plant growth as compared to single inoculants.

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 Screening of efficient rhizobacteria associated with cauliflower (Brassica oleraceavar. botrytis L.) for plant growth promoting traits

2017 ◽  
Vol 9 (1) ◽  
pp. 167-172
Author(s):  
Sonal Bhardwaj ◽  
Bhawna Dipta ◽  
Shruti Kirti ◽  
Rajesh Kaushal
Keyword(s):  
Plant Growth ◽  
Growth Promotion ◽  
Himachal Pradesh ◽  
Pgp Traits ◽  
Antifungal Metabolites ◽  
Stalk Rot ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phosphate Solubilizing

In the current study, a total of 25 isolates were isolated from the rhizosphere and roots of cauliflower (Brassica oleraceavar. botrytis L.) from the vicinity of Una district of Himachal Pradesh. The isolates were tested in vitro for their ability to solubilise phosphorous and produce siderophore, indole acetic acid (IAA), hydrogen cyanide (HCN) and antifungal metabolites against the soil borne pathogens. Results revealed that out of 25, only 4 rhizospheric isolates (SB5, SB11, SB8 and SB10) have maximum plant growth promoting attributes. The isolates were identified as Bacillus sp. on the basis of Bergey’s manual of systematic bacteriology. The isolate SB11 recorded highest phosphate solubilizing efficiency in solid medium (109.09%) and in liquid medium (350μg/ml). Maximum production of IAA (51.96μg/ml), siderophore (91.41%) and HCN were also observed for the same isolate. Further-more, the isolate SB11 produced highest antifungal metabolite production against Rhizoctoniasolani(37.11%), Sclerotiniasclerotiorum(41.11%), and Pythium sp. (71.11%) causing root rot, stalk rot and damping off diseases in cauliflower, respectively. The selected isolate (SB11) showed optimum growth at a pH of 7.0, 35°C temperature and 2% NaCl. On the basis of multifarious PGP-traits the SB11 isolate has tremendous potential to be used as a bioferti-lizer/bioprotectant for growth promotion and natural protection of cauliflower under low hill conditions of Himachal Pradesh.

scholarly journals Phenetic Characterization of Nitrogen Fixing Azotobacter from Rhizospheric Soil of Southern Rajasthan

2021 ◽  
Vol 15 (1) ◽  
pp. 428-436
Author(s):  
Devendra Jain ◽  
Gunnjeet Kaur ◽  
Ali Asger Bhojiya ◽  
Surya Chauhan ◽  
S.K. Khandelwal ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Root ◽  
Cyst Formation ◽  
Bromothymol Blue ◽  
Pgp Traits ◽  
Gram Staining ◽  
Indigenous Plant ◽  
Plant Growth Promoting ◽  
Growth Promoting

The present research was conducted to characterize the indigenous plant growth promoting (PGP) Azotobacter strains isolated from plant root interface of semi-arid regions of Rajasthan (India) and to study their potential to be used as bio-fertilizers. A total of 172 Azotobacter strains were isolated, purified and based on the morphological test i.e. gram staining, pigmentation, cyst formation, fluorescence etc, broadly classified as Azotobacter. Further the secluded strains were examined for biochemical analysis and plant growth promoting characters. All the isolates showed different biochemical characteristics and significant PGP traits. IAA activity of the Azotobacter strains ranges from 54.5-6000 µg/mL. Ammonia, HCN and siderophore was produced by 92.4%, 78.4% and 80.23% of the total isolates respectively. Solubilization of phosphate was observed in 97.6% of the total isolates. These strains were also characterized for qualitative and quantitative N2 fixation abilities and the result indicated that 114 strains showed positive results on nitrogen free malate agar medium (NFMM) containing bromothymol blue (BTB) and able to produce 18.93-475.6 N-moles C2H4 mg protein−1 h−1 of acetylene reduced by Azotobacter strains. In vitro pot studies revealed that the selected native Azotobacter strains having high ARA results significantly increase the plant growth characters. Shoot length, root length, root number and chlorophyll content and leaf number increases by 45.62%, 17.60%, 97.49%, 49.69% and 27.83% respectively in pot inoculated with AZO23-3 as compared to control. These effective strains can further be utilized for development of effective microbial formulations.

Endophytic bacterial communities of field-grown potato plants and their plant-growth-promoting and antagonistic abilities

2004 ◽  
Vol 50 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Angela Sessitsch ◽  
Birgit Reiter ◽  
Gabriele Berg
Keyword(s):  
16S Rrna ◽  
Plant Growth ◽  
Bacterial Pathogens ◽  
Antagonistic Activity ◽  
Streptomyces Scabies ◽  
Rrna Genes ◽  
Associated Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting

To study the effect of plant growth on potato-associated bacteria, the composition and properties of bacteria colonizing the endosphere of field-grown potato were analyzed by a multiphasic approach. The occurrence and diversity of potato-associated bacteria were monitored by a cultivation-independent approach, using terminal restriction fragment length polymorphism analysis of 16S rDNA. The patterns obtained revealed a high heterogeneity of community composition and suggested the existence of plant-specific communities. However, endophytic populations correlated to a certain extent with plant growth performance. Endophytes were also isolated from plants that grew well or grew poorly and were identified by partial sequencing of the 16S rRNA genes. A broad phylogenetic spectrum was found among isolates and differently growing plants hosted different bacterial populations. In an approach to investigate the plant-growth-promoting potential of potato-associated bacteria, a total of 35 bacteria were screened by dual testing for in vitro antagonism towards (i) the fungal pathogens Verticillium dahliae, Rhizoctonia solani, Sclerotinia sclerotiorum, and Phytophthora cactorum and (ii) the bacterial pathogens Erwinia carotovora, Streptomyces scabies, and Xanthomonas campestris. The proportion of isolates with antagonistic activity was highest against Streptomyces sp. (43%) followed by those against Xanthomonas sp. (29%). As all plants showed more or less severe disease symptoms of scab disease caused by Streptomyces scabies, we assume that the presence of the pathogen induced the colonization of antagonists. The antifungal activity of the isolates was generally low. The biotechnological potential of endophytic isolates assessed by their antagonistic activity and by in vitro production of enzymes, antibiotics, siderophores, and the plant growth hormone indole-1,3-acetic acid was generally high. Overall, seven endophytes were found to antagonize fungal as well as bacterial pathogens and showed a high production of active compounds and were therefore considered promising biological control agents.Key words: T-RFLP, 16S rRNA, siderophores, IAA, biocontrol.

scholarly journals Fusarium Oxysporum f. sp. Cannabis Isolated from Cannabis Sativa L.: In Vitro and in Planta Biocontrol by a Plant Growth Promoting-Bacteria Consortium

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2436
Author(s):  
Marika Pellegrini ◽  
Claudia Ercole ◽  
Carmelo Gianchino ◽  
Matteo Bernardi ◽  
Loretta Pace ◽  
...  
Keyword(s):  
Plant Growth ◽  
Fusarium Oxysporum ◽  
Cannabis Sativa ◽  
Antagonistic Activity ◽  
Plant Growth Promoting Bacteria ◽  
Dual Culture ◽  
In Planta ◽  
Plant Growth Promoting ◽  
Growth Promoting

Industrial hemp (Cannabis sativa L.) is a multipurpose plant used in several fields. Several phytopathogens attack hemp crops. Fusarium oxysporum is a common fungal pathogen that causes wilt disease in nurseries and in field cultivation and causes high losses. In the present study, a pathogenic strain belonging to F. oxysporum f. sp. cannabis was isolated from a plant showing Fusarium wilt. After isolation, identification was conducted based on morphological and molecular characterizations and pathogenicity tests. Selected plant growth-promoting bacteria with interesting biocontrol properties—Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae and Burkholderia ambifaria—were tested against this pathogen. In vitro antagonistic activity was determined by the dual culture method. Effective strains (in vitro inhibition > of 50%) G. diazotrophicus, H. seropedicae and B. ambifaria were combined in a consortium and screened for in planta antagonistic activity in pre-emergence (before germination) and post-emergence (after germination). The consortium counteracted Fusarium infection both in pre-emergence and post-emergence. Our preliminary results show that the selected consortium could be further investigated as an effective biocontrol agent for the management of this pathogen.

scholarly journals In vitro antagonism of five rhizobacterial species against athelia rolfsii collar rot disease in soybean

2018 ◽  
Vol 3 (1) ◽  
pp. 264-272 ◽  
Author(s):  
Irda Safni ◽  
Widya Antastia
Keyword(s):  
Plant Growth ◽  
Burkholderia Cepacia ◽  
Bacterial Species ◽  
Dual Culture ◽  
Collar Rot ◽  
Athelia Rolfsii ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Rot Disease

Abstract Plant Growth Promoting Rhizobacteria (PGPR) influence plant growth by a number of direct (producing plant growth promoting substances) and indirect (through prevention of deleterious effects of phytopathogenic microorganisms) mechanisms. Five species of bacteria were isolated from rhizospheric soils of soybean and peanut fields from several locations in North Sumatra. On the basis of morphological and biochemical characteristics, the bacteria were identified as Aeromonas hydrophila, Burkholderia cepacia, Serratia ficaria, Pantoea spp. 2, and Vibrio alginolyticus. These species were tested in vitro against the causal pathogen of collar rot disease of soybean, Athelia rolfsii, which is an important soybean disease in Indonesia. The five species of bacteria were subjected to screening of antagonistic activities against A. rolfsii in vitro with a dual culture-technique. Of the five species, B. cepacia, S. ficaria and V. alginolyticus were the most effective antagonistic bacteria to control A. rolfsii. B. cepacia, S. ficaria and V. algynolitycus produced inhibiting zones against A. rolfsii of 98.35%, 97.83% and 96.97% respectively. All bacterial species showed their antagonistic activity significantly with the inhibiting zone percentage being more than 60%. The experimental results suggested that all bacterial species have a future potency as a biocontrol agent to reduce A. rolfsii collar rot disease of soybean

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 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.

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