scholarly journals Isolation and evaluation of rhizobacteria against Ralstonia solanacearum the incitant of bacterial wilt of tomato

2020 ◽  
Vol 13 (2) ◽  
pp. 195-199
Author(s):  
C.S. Karibasappa ◽  
Yogendra Singh
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Inhibition Zone ◽  
Crop Plants ◽  
The Novel ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Biocontrol Activity ◽  
Highly Effective

Bacterial wilt caused by Ralstonia solanacearum is the world’s most economically important destructive disease of crop plants. In the current study, we aimed to evaluate the novel bacterial isolates from tomato rhizosphere for biocontrol of Ralstonia solanacearum. One eighty bacterial strains were isolated from the tomato rhizosperic soils collected from different regions of Uttarakhand state and evaluated for their biocontrol activity against R. solanacearum under in vitro conditions. Among them, six isolates were found to be highly effective in inhibiting the growth of R. solanacearum. The isolate GP2NA8 produced the highest inhibition zone followed by that of GP1NA2 and GP3NA6.

scholarly journals The PHYTOCHEMICALS, ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES OF Senna alata AND Senna tora LEAF EXTRACTS AGAINST BACTERIAL STRAINS CAUSING SKIN INFECTIONS

2019 ◽  
Vol 2 (1) ◽  
pp. 19
Author(s):  
Murni Halim
Keyword(s):  
Leaf Extract ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Leaf Extracts ◽  
Natural Drugs ◽  
Senna Alata

A study was carried out to screen for phytochemical constituents and assess the antioxidant and antimicrobial activities of Senna alata and Senna tora leaf extracts. The leaves were first dried at room temperature and 50°C in an oven prior to solvent extraction using ethanol and methanol. The in-vitro qualitative assays showed that both S. alata and S. tora leaf extracts contained bioactive and secondary metabolites components such as tannins, steroids, saponin, terpenoids, glycosides, flavonoids and phenols. The antioxidant activity and capacity test were carried out by conducting free radical of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and Ferric reduction antioxidant plasma (FRAP) assays. Both assays showed S. tora leaf extract has higher antioxidant capacity than S. alata leaf extract. The efficacy of these leaf extracts were tested against skin pathogens through agar well diffusion method. S. alata extract showed an inhibition zone (1.15 – 1.59 mm) against Pseudomonas aeruginosa while S. tora extracts exhibited a strong antimicrobial activity against S. epidermidis (inhibition zone of 12 – 16.94 mm) followed by P. aeruginosa (inhibition zone of 1 – 1.59 mm). Nonetheless, no inhibition zone was observed for S. aureus by both leaf extracts. The phytochemicals and antioxidant constituents as well as inhibitory potential on skin pathogens possessed by S. alata and S. tora leave highlighted their potential utilization in the development of natural drugs or cosmetics to treat skin related diseases or infections.

scholarly journals Streptomyces sp.: Characterization, Identification and Its Potential as a Ralstonia solanacearum Biological Control Agent in vitro

2019 ◽  
Vol 2 (3) ◽  
pp. 89-96 ◽  
Author(s):  
Rachmad Saputra ◽  
Triwidodo Arwiyanto ◽  
Arif Wibowo
Keyword(s):  
Biological Control ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Biological Control Agent ◽  
Wilt Disease ◽  
Molecular Characteristics ◽  
Streptomyces Sp ◽  
Bacterial Wilt Disease ◽  
Wide Range

Streptomyces sp. bacteria have the potential to produce antibiotic compounds, which are one of the mechanisms that are widely used in biological control. However, in general, biological control mechanisms also occur through competition, cell wall degradation and induced resistance. This study was aimed to determine the physiological, biochemical and molecular characteristics of two isolates of Streptomyces sp. (S-4 and S16 isolates) isolated from the tomatoes roots, and to find out their ability to control Ralstonia solanacearum, which causes bacterial wilt disease on a wide range of hosts. The results showed both Streptomyces sp. isolates had several different physiological and biochemical characteristics and had a different ability to inhibit R. solanacearum in vitro. Streptomyces sp. S-16 isolate had a high similarity with Streptomyces diastaticus subsp. ardesiacus strain NRRL B-1773T based on the molecular identification results. Further research needs to be done to see the potential inhibition of the two Streptomyces isolates in inhibiting the development of bacterial wilt disease in tomato plants caused by R. solanacearum.

scholarly journals Bioactivity of Selected Phenolic Acids and Hexane Extracts from Bougainvilla spectabilis and Citharexylum spinosum on the Growth of Pectobacterium carotovorum and Dickeya solani Bacteria: An Opportunity to Save the Environment

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 482 ◽  
Author(s):  
Nader A. Ashmawy ◽  
Said I. Behiry ◽  
Asma A. Al-Huqail ◽  
Hayssam M. Ali ◽  
Mohamed Z. M. Salem
Keyword(s):  
Phenolic Acids ◽  
Tannic Acid ◽  
Defense Mechanisms ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Inhibition Zone ◽  
Pectobacterium Carotovorum ◽  
Bacterial Isolates ◽  
Dickeya Solani

Phenolic acids and natural extracts, as ecofriendly environmental agents, can be used as bio bactericides against the growth of plant pathogenic bacteria. In this study, isolation trails from infected potato tubers and stems that showed soft rot symptoms in fields revealed two soft rot bacterial isolates and were initially identified through morphological, physiological, and pathogenicity tests. The molecular characterization of these isolates via PCR, based on the 16S rRNA region, was carried out by an analysis of the DNA sequence via BLAST and Genbank, and showed that the soft rot bacterial isolates belong to Pectobacterium carotovorum subsp. carotovorum (PCC1) and Dickeya solani (Ds1). The in vitro results of the tested phenolic acids against the cultured bacterial isolates proved that concentrations of 800, 1600, and 3200 μg/mL were the most effective. Ferulic acid was the potent suppressive phenolic acid tested against the Ds1 isolate, with an inhibition zone ranging from 6.00 to 25.75 mm at different concentrations (25–3200 μg/mL), but had no effect until reaching a concentration of 100 μg/mL in the PCC1 isolate, followed by tannic acid, which ranged from 7.00 to 25.50 mm. On the other hand, tannic acid resulted in a significant decrease in the growth rate of the PCC1 isolate with a mean of 9.11 mm. Chlorogenic acid was not as effective as the rest of the phenolic acids compared with the control. The n-hexane oily extract (HeOE) from Bougainvillea spectabilis bark showed the highest activity against PCC1 and Ds1, with inhibition zone values of 12 and 12.33 mm, respectively, at a concentration of 4000 μg/mL; while the HeOE from Citharexylum spinosum wood showed less activity. In the GC/MS analysis, nonanal, an oily liquid compound, was found ata percentage of 38.28%, followed by cis-2-nonenal (9.75%), which are the main compounds in B. spectabilis bark HeOE, and 2-undecenal (22.39%), trans-2-decenal (18.74%), and oleic acid (10.85%) were found, which are the main compounds in C. spinosum wood HeOE. In conclusion, the phenolic acids and plant HeOEs seem to raise the resistance of potato plants, improving their defense mechanisms against soft rot bacterial pathogens.

scholarly journals Genetic Diversity and Aggressiveness of Ralstonia solanacearum Strains Causing Bacterial Wilt of Potato in Uruguay

Plant Disease ◽  
2011 ◽  
Vol 95 (10) ◽  
pp. 1292-1301 ◽  
Author(s):  
M. I. Siri ◽  
A. Sanabria ◽  
M. J. Pianzzola
Keyword(s):  
Genetic Diversity ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Potato Tubers ◽  
Bacterial Strains ◽  
Potato Plants ◽  
Polymerase Chain ◽  
First Time ◽  
Different Levels

Bacterial wilt, caused by Ralstonia solanacearum, is a major disease affecting potato (Solanum tuberosum) production worldwide. Although local reports suggest that the disease is widespread in Uruguay, characterization of prevalent R. solanacearum strains in that country has not been done. In all, 28 strains of R. solanacearum isolated from major potato-growing areas in Uruguay were evaluated, including 26 strains isolated from potato tubers and 2 from soil samples. All strains belonged to phylotype IIB, sequevar 1 (race 3, biovar 2). Genetic diversity of strains was assessed by repetitive-sequence polymerase chain reaction, which showed that the Uruguayan strains constituted a homogeneous group. In contrast, inoculation of the strains on tomato and potato plants showed, for the first time, different levels of aggressiveness among R. solanacearum strains belonging to phylotype IIB, sequevar 1. Aggressiveness assays were also performed on accessions of S. commersonii, a wild species native to Uruguay that is a source of resistance for potato breeding. No significant interactions were found between bacterial strains and potato and S. commersonii genotypes, and differences in aggressiveness among R. solanacearum strains were consistent with previously identified groups based on tomato and potato inoculations. Moreover, variation in responses to R. solanacearum was observed among the S. commersonii accessions tested.

scholarly journals Type III Secretion–Dependent and –Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots

2018 ◽  
Vol 31 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Haibin Lu ◽  
Saul Lema A ◽  
Marc Planas-Marquès ◽  
Alejandro Alonso-Díaz ◽  
Marc Valls ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Defense Responses ◽  
Bacterial Virulence ◽  
Root Tip ◽  
Root Growth Inhibition ◽  
Virulence Determinants ◽  
Root Hair Formation ◽  
Set Up

The causal agent of bacterial wilt, Ralstonia solanacearum, is a soilborne pathogen that invades plants through their roots, traversing many tissue layers until it reaches the xylem, where it multiplies and causes plant collapse. The effects of R. solanacearum infection are devastating, and no effective approach to fight the disease is so far available. The early steps of infection, essential for colonization, as well as the early plant defense responses remain mostly unknown. Here, we have set up a simple, in vitro Arabidopsis thaliana–R. solanacearum pathosystem that has allowed us to identify three clear root phenotypes specifically associated to the early stages of infection: root-growth inhibition, root-hair formation, and root-tip cell death. Using this method, we have been able to differentiate, on Arabidopsis plants, the phenotypes caused by mutants in the key bacterial virulence regulators hrpB and hrpG, which remained indistinguishable using the classical soil-drench inoculation pathogenicity assays. In addition, we have revealed the previously unknown involvement of auxins in the root rearrangements caused by R. solanacearum infection. Our system provides an easy-to-use, high-throughput tool to study R. solanacearum aggressiveness. Furthermore, the observed phenotypes may allow the identification of bacterial virulence determinants and could even be used to screen for novel forms of early plant resistance to bacterial wilt.

scholarly journals Effect of Allium fistulosum Extract on Ralstonia solanacearum Populations and Tomato Bacterial Wilt

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 687-692 ◽  
Author(s):  
Péninna Deberdt ◽  
Benjamin Perrin ◽  
Régine Coranson-Beaudu ◽  
Pierre-François Duyck ◽  
Emmanuel Wicker
Keyword(s):  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Management Strategies ◽  
Antimicrobial Effect ◽  
Allium Fistulosum ◽  
Inhibition Assay ◽  
In Vivo Experiments ◽  
Tomato Bacterial Wilt

To control bacterial wilt (Ralstonia solanacearum, phylotype IIB/4NPB), the antimicrobial effect of Allium fistulosum aqueous extract was assessed as a preplant soil treatment. Three concentrations of extract (100, 50, and 25%, 1:1 [wt/vol]) were evaluated by in vitro inhibition assay and in vivo experiments in a growth chamber. In vitro, A. fistulosum (100 and 50%) suppressed growth of R. solanacearum. Preplant treatment of the soil with A. fistulosum extract significantly reduced the R. solanacearum populations. No pathogen was detected in the soil after treatment with 100% concentrated extract from the third day after application until the end of the experiment. A. fistulosum also significantly reduced the incidence of tomato bacterial wilt. In the untreated control, the disease affected 61% of the plants whereas, with 100 and 50% extracts, only 6 and 14% of the plants, respectively, were affected. These results suggest that A. fistulosum extracts could be used in biocontrol-based management strategies for bacterial wilt of tomato.

scholarly journals Biological control of bacterial wilt in tomato through the metabolites produced by the biocontrol fungus, Trichoderma harzianum

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Liu Yan ◽  
Raja Asad Ali Khan
Keyword(s):  
Plant Growth ◽  
Disease Severity ◽  
Bacterial Wilt ◽  
Trichoderma Harzianum ◽  
Bacterial Population ◽  
Inhibition Zone ◽  
Greenhouse Experiment ◽  
Fungal Metabolites ◽  
Tomato Plants

Abstract Background Ralstonia solanacearum causes bacterial wilt disease in tomato and other crops resulting in huge economic losses worldwide. Several measures have been explored for the control of R. solanacearum, but the desired control level of the disease through sustainable and ecofriendly way is still awaited. Main body In this study, fungal metabolites produced by Trichoderma harzianum were investigated in the form of crude extract for the management of R. solanacearum both in vitro and in planta in tomato plants. In in vitro investigation, fungal metabolites were checked for their antibacterial potential at different concentrations (30, 60, 90, 120, 150, and 180 mg ml−1) and bacterial cell morphology was observed under scanning electron microscopy (SEM). In a greenhouse experiment, different application times (0, 3, and 6 days before transplantation DBT) and doses (0, 3, 6, and 9%) of the fungal metabolites were tested for their effects on soil bacterial population, disease severity and plant growth of tomato plants. The in vitro evaluation showed a strong antibacterial activity of fungal metabolites in concentration dependent manner. The highest concentration 180 mg ml−1 produced maximum inhibition zone (20.2 mm) having non-significant difference with the inhibition zone (20.5 mm) produced by the standard antibiotic streptomycin. The SEM analysis revealed severe morphological destructions of bacterial cells. In case of greenhouse experiment, the highest decrease in soil bacterial population, lowest disease severity, and maximum increase in plant growth parameters were obtained by highest dose (9%) and longest application time (6 DBT). Conclusion The fungal metabolites produced by T. harzianum could be used as low-cost, environment-friendly, and sustainable management strategy for the control of R. solanacearum in tomato plants.

scholarly journals Biological control of Ralstonia solanacearum (Smith), the causal pathogen of bacterial wilt disease by using Pantoea spp

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Sabry A. Hassan
Keyword(s):  
Biological Control ◽  
Cell Suspension ◽  
Disease Severity ◽  
Culture Filtrate ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Wilt Disease ◽  
Nucleotide Sequence Analysis ◽  
Tomato Root

Abstract Background Bacterial wilt of tomato (BWP) caused by Ralstonia solanacearum (Smith) is a very important disease. Biological control of this disease is a very important tool to protect the plant and environment from pollution of chemical control. Results Twenty isolates of genus, Pantoea were isolated from healthy tomato root. Out of 20 isolates, 2 strains, PHYTPO1 and PHYTPO2, showed highly antagonistic property to control the growth of R. solanacearum in vitro conditions. They were identified as P. agglomerans by using 16S rRNA nucleotide sequence analysis. The 2 isolates were selected to study their effect (as cell suspension or culture filtrate) on the bacterial wilt under greenhouse conditions. PHYTPO1 inhibited maximum growth reduction of R. solanacearum and formed 2.5 cm2 of inhibition zone, followed by 1.2 cm2 in PHYTOPO2 under in vitro conditions. Treating with both isolates of P. agglomerans was significantly reduced disease severity of tomato wilt disease. The disease severity was reduced to 74.1 when treated as cell suspension, while when treated as culture filtrate, it reduced the disease severity up to 69.4 than infected control. Conclusion The strains of Pantoea can be used as an ecofriendly method to control of the most economic pathogen of tomato under greenhouse conditions. Further study is needed to find an appropriate formulation and approving application of these bacteria under field conditions.

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