• The Plant Pathology Journal
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• v.25 no.3
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• pp.256-262
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• 2009

The potential of. nonpathogenic Fusarium oxysporum strain Avr5, either alone or in combination with chitosan and Bion, for inducing defense reaction in tomato plants inoculated with F. oxysporum f. sp lycopersici, was studied in vitro and glasshouse conditions. Application Bion at concentration of 5, 50, 100 and $500{\mu}g$/ml, and the highest concentration of chitosan reduced in vitro growth of the pathogen. Nonpathogenic F. oxysporum Avr5 reduced the disease severity of Fusarium wilt of tomato in split plants, significantly. Bion and chitosan applied on tomato seedlings at concentration $100{\mu}g$ a.i./plant; 15, 10 and 5 days before inoculation of pathogen. All treatments significantly reduced disease severity of Fusarium wilt of tomato relative to the infected control. The biggest disease reduction and increasing tomato growth belong to combination of nonpathogenic Fusarium and Bion. Growth rate of shoot and root markedly inhibited in tomato plants in response to tomato Fusarium wilt as compared with healthy control. These results suggest that reduction in disease incidence and promotion in growth parameters in tomato plants inoculated with nonpathogenic Fusarium and sprayed with elicitors could be related to the synergistic and cooperative effect between them, which lead to the induction and regulation of disease resistance. Combination of elicitors and non-pathogenic Fusarium synergistically inhibit the growth of pathogen and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in tomato. This chemical could provide a new approach for suppression of tomato Fusarium wilt, but its practical use needs further investigation.

• Mycobiology
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• v.43 no.3
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• pp.311-318
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• 2015

Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding ${\beta}$-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.

• Research in Plant Disease
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• v.29 no.1
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• pp.82-87
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• 2023

Exogenous ferrous chloride (FeCl₂) suppressed in vitro growth of Ralstonia pseudosolanacearum, causing bacteria for tomato bacterial wilt. More than 50 μM of FeCl₂ reduced the in vitro bacterial growth in dosedependent manners. Two to 200 μM of FeCl₂ did not affect the fresh weight of detached tomato leaves at 3 and 5 days after the petiole dipping without the bacterial inoculation. The bacterial wilt of the detached tomato leaves was evaluated by inoculating two different inoculum densities of R. pseudosolanacearum (10⁵ and 10⁷ cfu/ml) in the presence of FeCl₂. Bacterial wilt in the detached leaves by 10⁵ cfu/ml was efficiently attenuated by 10-200 μM of FeCl₂ at 3 and 5 days post-inoculation (dpi), but bacterial wilt by 10⁷ cfu/ml was only reduced by 200 μM of FeCl₂ at 3 and 5 dpi. These results suggest that iron nutrients can be included in the integrated disease management of tomato bacterial wilt.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.323-329
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• 2016

Water extract from spent mushroom substrate (WESMS) of Pleurotus eryngii suppressed bacterial wilt disease of tomato caused by Ralstonia solanacearum by 70% without any direct antibacterial activity against the pathogen. WESMS-treated tomato had increased contents of free phenolic compounds (increased by 3%) and total salicylic acid (increased by 75%), and significantly enhanced plant height, leaf number, and fresh weight compared to those of a water-treated tomato sample. These results suggest that the treatment of tomato with WESMS can suppress bacterial wilt disease by enhancing plant defense factors and overall plant health.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.263-269
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• 2009

Bacterial wilt, Fusarium wilt and Foot rot caused by Ralstonia solanacearum, Fusarium oxysporum, and Phytophthora capsici respectively, continue to be severe problems to tomato, potato and black pepper growers in Vietnam. Three bio-products, Bacillus vallismortis EXTN-1 (EXTN-1), Bacillus sp. and Paenibacillus sp. (ESSC) and Bacillus substilis (MFMF) were examined in greenhouse bioassay for the ability to reduce bacterial wilt, fusarium wilt and foot rot disease severity. While these bio-products significantly reduced disease severities, EXTN-1 was the most effective, providing a mean level of disease reduction 80.0 to 90.0% against bacterial wilt, fusarium wilt and foot rot diseases under greenhouse conditions. ESSC and MFMF also significantly reduced fusarium wilt, bacterial wilt and foot rot severity under greenhouse conditions. Bio-product, EXTN-1 with the greatest efficacy under greenhouse condition was tested for the ability to reduce bacterial wilt, fusarium wilt and foot rot under field condition at Song Phuong and Thuong Tin locations in Ha Tay province, Vietnam. Under field condition, EXTN-1 provided a mean level of disease reduction more than 45.0% against all three diseases compared to water treated control. Besides, EXTN-1 treatment increased the yield in tomato fruits 17.3% than water treated control plants.

• The Plant Pathology Journal
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• v.32 no.1
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• pp.58-64
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• 2016

Bacterial wilt of tomatoes caused by Ralstonia solanacearum is a devastating disease that limits the production of tomato in Korea. The best way to control this disease is using genetically resistant tomato plant. The resistance degree to R. solanacearum was evaluated for 285 tomato accessions conserved in the National Agrobiodiversity Center of Rural Development Administration. These accessions of tomato were originated from 23 countries. Disease severity of tomato accessions was investigated from 7 days to 14 days at an interval of 7 days after inoculation of R. solanacearum under greenhouse conditions. A total of 279 accessions of tomato germplasm were susceptible to R. solanacearum, resulting in wilt and death in 70 to 90% of these plants. Two tomato accessions were moderately resistant to R. solanacearum. Only four accessions showed high resistance against R. solanacearum. No distinct symptom of bacterial wilt appeared on the resistant tomato germplasms for up to 14 days after inoculation of R. solanacearum. Microscopy of resistant tomato stems infected with R. solanacearum revealed limited bacterial spread with thickening of pit membrane and gum production. Therefore, these four resistant tomato germplasms could be used in tomato breeding program against bacterial wilt.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.199-204
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• 2009

Three plant growth-promoting yeasts and two rhizobacteria were tested for controlling tomato wilt caused by Fusarium oxysporum f. sp. lycopersici under green-house and field conditions. Under greenhouse and field conditions, all treatments were significantly reduced disease severity of tomato wilt relative to the infected control. The highest disease reductions in pots (75.0, 67.4%) and field (52.5, 42.4%) were achieved by Azospirillum brasilense and Bacillus subtilis compared to infected control. Under field condition all treatments produced the highest tomato yield compared to the control plants inoculated with the pathogen.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.299-303
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• 2014

This study aims to isolate and identify the causal pathogen of tomato bacterial wilt in Egypt. In 2008, tomato plants showing typical symptoms of bacterial wilt disease with no foliar yellowing were observed in Minia, Assiut and Sohag governorates, Egypt. When cut stems of symptomatic plants were submerged in water, whitish ooze was evident and longitudinal sections showed a brown discoloration in the vascular tissues. Bacteria were isolated on triphenyl tetrazolium chloride medium and fifteen isolates shown typical morphological and cultural characteristics were confirmed as Ralstonia solanacearum biovar 2 race 1. Pathogenicity tests showed that all isolates proved to be pathogenic to tomato plants, varied from 52 to 97% wilting. This is the first report of R. solanacearum biovar 2 race 1 causing bacterial wilt in tomato crop in Egypt.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.386-396
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• 2013

Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide ($H_2O_2$) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion ($O_2{^-}$) and $H_2O_2$ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of $H_2O_2$ and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both $H_2O_2$ and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by $10^6$ and $10^7$ cfu/ml of R. solanacearum. $H_2O_2$- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by $H_2O_2$ and/or SNP with untreated control. Neither $H_2O_2$ nor SNP protect the tomato seedlings from the bacterial wilt, but $H_2O_2$ + SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that $H_2O_2$ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

• Research in Plant Disease
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• v.19 no.2
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• pp.108-113
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• 2013

Wilt damage on tomato plants caused by Ralstonia solanacearum has been increased as the areas of tomato cultivation increased during the warm seasons. Also, the tomato rootstocks used to prevent the disease occurrence are not effective in the highly prevailing regions. Therefore, bacterial wilt resistant eggplant rootstock EG203, collected from AVRDC, was tested for its effect to deter the Ralstonia solanacearum wilt disease in the greenhouses at Buyeo Tomato Experiment Station from 2003 to 2005, and at Gumi, Kyungpook province from 2009-2011. Planting of eggplant rootstock EG203 should be done three weeks before the planting of tomato scions so that they can have similar stem diameter (2.5-3.0 mm) and can be easily grafted. Both insertion and inarching grafting showed 93-96% success rates. In the greenhouse tests at Buyeo Tomato Experiment Station from 2003 to 2005, eggplant rootstock EG203-grafted tomatoes showed the disease occurrence of 4.3%. On the other hand, non-grafted or other commercial rootstock-grafted tomatoes showed disease occurrence of 58.0% and 25.0-36.7%, respectively. In the greenhouse tests at Gumi, Kyungpook province in 2009, the disease occurrence on the EG203-grafted and non-grafted tomatoes was 2-5% and 20-80%, respectively. In 2010, at Gumi, Kyungpook province, when the wilt disease occurred slightly, the tomatoes grafted with tomato rootstocks B-blocking and Chung-gang, and eggplant rootstock EG203 showed similar disease severities, but EG203-grafted tomatoes formed lately cluster, resulting in the reduction of yield compared to tomato-grafted tomatoes. In 2011, at Gumi, Kyungpook province, when the wilt disease occurred severely, the tomato rootstocks 'B-blocking' and Chung-gang and eggplant rootstock EG203-grafted tomatoes showed disease occurrences of 60-85% and 0-1%, respectively. Therefore, it was concluded that tomato rootstocks 'B-blocking' and 'Chung-gang' are more useful in the areas contaminated with low levels of pathogen and eggplant rootstock EG203 is more useful in the areas contaminated with high levels of pathogen.