scholarly journals Biocontrol of Sclerotium rolfsii Using Antagonistic Activities of Pseudomonads

2019 ◽  
pp. 1-9
Author(s):  
Sangita Sahni ◽  
Bishun Deo Prasad ◽  
Tushar Ranjan
Keyword(s):  
Calcium Phosphate ◽  
Plant Growth ◽  
Sclerotium Rolfsii ◽  
Antagonistic Activity ◽  
Biocontrol Agents ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Unique Ability ◽  
Plant Growth Promoting Traits

Thirty well-characterized pseudomonad isolates for plant growth-promoting traits were screened for their antagonistic activities against 20 isolates of Sclerotium rolfsii. Out of the 30 pseudomonad isolates, PUR46 was found to be best against all 20 isolates of Sclerotium rolfsii, because of its unique ability to suppress the growth of mycelia as well as the sclerotia formation of most of the S. rolfsii isolates in vitro conditions. In our previous study, PUR46 was also found to be positive for growth promoting traits like phosphorus solubilization and ammonification. The results suggested that expression of one or more of the traits like antagonistic activity against S. rolfsii and solubilization of tri-calcium phosphate may help in controlling the pathogen besides enhancement of plant growth. In this study, our investigations clearly indicate that PGPR isolates PUR 46 may be exploited to be used as potential biocontrol agents against S. rolfsii in agriculture system.

scholarly journals Physiological Adaptation and Plant Growth Promoting Functional Traits of Bacillus altitudinis FD48 under In vitro Osmotic Stress

2020 ◽  
pp. 92-98
Author(s):  
Shobana Narayanasamy ◽  
Sugitha Thankappan ◽  
Sivakumar Uthandi
Keyword(s):  
Plant Growth ◽  
Osmotic Stress ◽  
Functional Traits ◽  
Physiological Adaptation ◽  
Bacillus Altitudinis ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
The Impact ◽  
Plant Growth Promoting Traits

To develop an osmotolerant microbe, as a bioinoculant to mitigate drought it is vital to understand the impact of osmotic stress on their growth and plant growth promoting functional traits. The present study was aimed to evaluate the physiological adaptations and plant growth-promoting traits of a phyllosphere bacterium Bacillus altitudinis FD48 under osmotic stress conditions. The FD48 strain isolated from rice (cultivar ADT43) phyllosphere obtained from Biocatalysts laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore. In vitro bioassay was conducted to evaluate the osmotolerant potentials of FD48. B. altitudinis FD48 grown in LB supplemented with PEG 6000 and grown for 48 hrs. Physiological adaptation to osmotic stress was observed by assessing the osmolytes and free amino acids content produced by FD48 under induced stress. Further the plant growth promoting traits under osmotic stress also asceratined. The growth pattern of FD48 strain decreased with the increase in PEG concentrations. The lower level of osmotic stress enhanced the growth of FD48 but at higher concentration exhibited a decline in growth. Enhanced levels of IAA (25 µg g-1 of protein) and EPS (9.76 mg mg-1 protein) production were recorded in the FD48 strain at lower levels of osmotic stress. Furthermore, an increase in osmotic stress had a deleterious effect on IAA production and ACC deaminase activity while the exopolysaccharide production was enhanced. Growth of FD48 under osmotic stress also increased the accumulation of proline and compatible sugars that will protect the FD48 strain by maintaining the turgor potential of cells and stabilizes the membrane proteins. Hence, the results of our study suggesting that, B. altitudinis FD48 strain has the potential to tolerate osmotic stress and might be used as a newer bio-inoculant for triggering moisture deficit stress resilience in plants.

scholarly journals Isolation and screening of multifunctional rhizobacteria from the selected sites of Madhupur, Narshingdi and Mymensingh, Bangladesh

2015 ◽  
Vol 2 (1) ◽  
pp. 1-8
Author(s):  
Moonmoon Nahar Asha ◽  
Atiqur Rahman ◽  
Quazi Forhad Quadir ◽  
Md Shahinur Islam
Keyword(s):  
Plant Growth ◽  
Crop Production ◽  
Plant Growth Promoting Rhizobacteria ◽  
N Fixation ◽  
National Botanical Research Institute ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Botanical Research ◽  
Plant Growth Promoting Traits

A laboratory experiment was performed to isolate some native rhizobacteria that could be used as bioinoculants for sustainable crop production. A total of 43 rhizobacteria were isolated from undisturbed plant rhizosphere soils of three different locations of Bangladesh and evaluated their plant growth promoting traits, both direct and indirect. The study has screened out isolates on the basis of their phosphorous solubilization and nitrogen (N) fixation. The phosphate solubilization assay in National Botanical Research Institute of Phosphate (NBRIP) medium revealed that 12 bacterial isolates were able to solubilize tricalcium phosphate and the rhizobacteria M25 showed best performance with a PSI of 3.33 at 5 day. Exactly 47% (20 isolates) of the isolated rhizobacteria were able to grow in N-free Winogradsky’s medium, which is an indication of potential N2-fixers. Among the 20 potential N-fixers, 15 were able to grow within 24 hours of incubation indicating that they are more efficient in Nfixation. The present study successfully isolated and characterized 43 rhizobacteria. Some of these isolated rhizobacteria have potential plant growth promoting traits and are potential plant growth promoting rhizobacteria (PGPR) candidate. Considering all plant growth promoting traits, the isolate F37 was the best followed by M6. However, further experiments are needed to determine the effectiveness of these isolates under in vitro and different field conditions to understand the nature of interaction with the plant and environment.Res. Agric., Livest. Fish.2(1): 1-8, April 2015

scholarly journals Genomic and Metabolomic Insights into Secondary Metabolites of the Novel Bacillus halotolerans Hil4, an Endophyte with Promising Antagonistic Activity against Gray Mold and Plant Growth Promoting Potential

2021 ◽  
Vol 9 (12) ◽  
pp. 2508
Author(s):  
Eirini-Evangelia Thomloudi ◽  
Polina C. Tsalgatidou ◽  
Eirini Baira ◽  
Konstantinos Papadimitriou ◽  
Anastasia Venieraki ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Promotion ◽  
Gene Clusters ◽  
Gray Mold ◽  
Antagonistic Activity ◽  
Future Research ◽  
Single Culture ◽  
Plant Growth Promoting ◽  
Growth Promoting

The endophytic bacterial strain Hil4 was isolated from leaves of the medicinal plant Hypericum hircinum. It exhibited antifungal activity against Botrytis cinerea and a plethora of plant growth promoting traits in vitro. Whole genome sequencing revealed that it belongs to Bacillus halotolerans and possesses numerous secondary metabolite biosynthetic gene clusters and genes involved in plant growth promotion, colonization, and plant defense elicitation. The Mojavensin cluster was present in the genome, making this strain novel among plant-associated B. halotolerans strains. Extracts of secreted agar-diffusible compounds from single culture secretome extracts and dual cultures with B. cinerea were bioactive and had the same antifungal pattern on TLC plates after bioautography. UHPLC-HRMS analysis of the single culture secretome extract putatively annotated the consecutively produced antimicrobial substances and ISR elicitors. The isolate also proved efficient in minimizing the severity of gray mold post-harvest disease on table grape berries, as well as cherry tomatoes. Finally, it positively influenced the growth of Arabidopsis thaliana Col-0 and Solanum lycopersicum var. Chondrokatsari Messinias after seed biopriming in vitro. Overall, these results indicate that the B. halotolerans strain Hil4 is a promising novel plant growth promoting and biocontrol agent, and can be used in future research for the development of biostimulants and/or biological control agents.

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.

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