Tomato Bacterial Wilt Disease Research Articles

Identification and application of Streptomyces microflavus G33 in compost to suppress tomato bacterial wilt disease

Tomato bacterial wilt caused by Ralstonia solanacearum is the most destructive disease impacting production. Application of bioorganic fertilizer (BOF) containing antagonistic microorganism to suppress tomato bacterial wilt disease may be a promising disease control strategy. Here, we used organic waste materials, specifically biogas residues, cattle manure and rice straw, in composting with antagonistic strain G33 isolated from the rhizosphere soil of a healthy tomato plant to produce BOF. Strain G33 was identified as Streptomyces microflavus by morphological and culturing traits and by 16S rRNA gene sequence analysis. We conducted a field experiment with control treatment, organic fertilizer and BOF-G33 to characterize suppression of tomato bacterial wilt disease. Our results indicate that the optimal combination containing (w/w) 40% biogas residues, 40% cattle manure and 20% rice straw can increase the nutrient contents of the compost product, prolong the thermophilic period and increase the decomposition rate of organic matter and the humification degree. A combination of strain G33 and mature compost produced under optimal conditions resulted in the spore number of 5.75 × 109 CFU/g on the sixth day of fermentation. Field experiments showed that BOF-G33 significantly decreased the incidence of tomato wilt; the disease biocontrol efficiency was 64.4%. In addition, application of the BOF-G33 significantly reduced the pathogenic R. solanacearum populations and increased the abundance of beneficial indigenous flora in the rhizosphere soil, which might have been the key factors in constraining the disease. In conclusion, this study showed that bioorganic fertilizer with Streptomyces microflavus G33 is a potential biocontrol agent for controlling tomato bacterial disease.

Evaluation of integrated management of bacterial wilt of tomato using grafting, biofumigant and plant resistance activator under field conditions

Bacterial wilt, caused by Ralstonia solanacearum, is a major and constant constraint in the production of tomatoes worldwide. A two-season field experiments, laid out in two separate orchards in a randomized complete block design and a split-split plot arrangement with three replications, was conducted to evaluate the integrated effect of grafting, thymol and acibenzolar-S-methyl (ASM) in the management of tomato bacterial wilt disease in a naturally infested soil. Beske and UC82-B tomato cultivars, susceptible to the pathogen, were grafted on a resistant tomato rootstock (Tomachiva) while thymol (0.7% w/v) was applied as a pre-plant soil fumigant. Grafted and non-grafted tomato received ASM as foliar spray after transplanting. Sole or combined application of the enhancers (thymol and ASM) had significant reduction of bacterial wilt incidence in both seasons, from the second to eight weeks after transplanting. At eighth week after transplanting, the effect of combined application of thymol and ASM translated to 100% and 90.3% disease reduction in early and late planting seasons, respectively. Grafted tomato, thymol and ASM combination produced an average yield of 74.3 and 86.9 ton/ha in early and 65.3 and 58.1 ton/ha in late planting seasons respectively. The findings indicated that integrated use of grafting, thymol (0.7% w/v) and ASM (30 µg/ml) could be of great benefit in the control of bacterial wilt of tomato.

Phage Cocktail Therapy: Multiple Ways to Suppress Pathogenicity

Phage cocktails have emerged as precision tools for controlling plant bacterial diseases. Wang et al. now report that phage cocktails decreased the occurrence of tomato bacterial wilt disease efficiently by infecting and destroying bacterial pathogens, selecting phage-resistant but slow-growing pathogen strains, and fostering bacterial species that are antagonistic to the pathogens.

Phage combination therapies for bacterial wilt disease in tomato.

Bacteriophages have been proposed as an alternative to pesticides to kill bacterial pathogens of crops. However, the efficacy of phage biocontrol is variable and poorly understood in natural rhizosphere microbiomes. We studied biocontrol efficacy of different phage combinations on Ralstonia solanacearum infection in tomato. Increasing the number of phages in combinations decreased the incidence of disease by up to 80% in greenhouse and field experiments during a single crop season. The decreased incidence of disease was explained by a reduction in pathogen density and the selection for phage-resistant but slow-growing pathogen strains, together with enrichment for bacterial species that were antagonistic toward R. solanacearum. Phage treatment did not affect the existing rhizosphere microbiota. Specific phage combinations have potential as precision tools to control plant pathogenic bacteria.

Rhizosphere bacteria assembly derived from fumigation and organic amendment triggers the direct and indirect suppression of tomato bacterial wilt disease

With no efficient method widely recognized for controlling or preventing tomato bacterial wilt, a devastating disease caused by the soil-borne bacterium Ralstonia solanacearum, tomato production is severely hindered. Therefore, the objective was thus to provide a strategy based on fumigation using ammonium bicarbonate along with organic amendment to reduce disease severity, and the impact of this treatment on the soil microbiome as well as the underlying mechanism leading to disease suppression were evaluated using high-throughput sequencing. Results showed that this combined strategy effectively controls tomato bacterial wilt disease despite the high abundance of R. solanacearum in both the bulk and rhizosphere soil in all treatments. The treatment led to significant changes in the soil bacterial and fungal communities, and at harvest time, fumigation and organic amendment equally affected the variation in the rhizosphere microbiome. Further, a shift in the rhizosphere bacterial community acted as the key factor directly and indirectly suppressing R. solanacearum and controlling bacterial wilt disease. In addition, Rhodanobacter, Terrimonas and Chitinophaga in the rhizosphere were the potential taxa involved in disease suppression. Both fumigation and organic amendment contributed to disease suppression by decreasing the abundance of R. solanacearum and altering the bacterial composition in combination with the stimulation of key bacterial taxa.

The RSc0454-Encoded FAD-Linked Oxidase Is Indispensable for Pathogenicity in Ralstonia solanacearum GMI1000.

Ralstonia solanacearum is the causal agent of bacterial wilt disease. Here, we report that a large FAD-linked oxidase encoded by RSc0454 in GMI1000 is required for pathogenicity. The FAD-linked oxidase encoded by RSc0454 is composed of 1,345 amino acids, including DUF3683, lactate dehydrogenase (LDH), and succinate dehydrogenase (SDH) domains. The RSc0454 protein showed both LDH and SDH activities. To investigate its role in pathogenicity, a deletion mutant of the RSc0454 gene was constructed in GMI1000, which was impaired in its ability to cause bacterial wilt disease in tomato. A single DUF3683, LDH, or SDH domain was insufficient to restore bacterial pathogenicity. Mutagenesis of the RSc0454 gene did not affect growth rate but caused cell aggregation at the bottom of the liquid nutrient medium, which was reversed by exogenous applications of lactate, fumarate, pyruvate, and succinate. qRT-PCR and promoter LacZ fusion experiments demonstrated that RSc0454 gene transcription was induced by lactate and fumarate (both substrates of LDH). Compared with the downregulation of the succinate dehydrogenase gene sdhBADC and the lactate dehydrogenase gene ldh, RSc0454 gene transcription was enhanced in planta. This suggests that the oxidase encoded by RSc0454 was involved in a redox balance, which is in line with the different living conditions of R. solanacearum.

Induced Defense Related Enzyme Activities of Tomato Plant by Indigenous Endophytic Bacteria and Challenged by Ralstonia Syzigii Subsp. Indonesiensis

Our previous research had screened 9 best indigenous endophytic isolates for their ability to control Ralstonia syzigii subsp. indonesiensis, the causal agents of bacterial wilt disease in tomato (Lycopersicon esculentum) in green house condition. Those 9 strains were Bacillus cereus EPL1.1.3, B. cereus TLE2.3, B. toyonensis EPL1.1.4, Serratia nematodiphila TLE1.1, B. anthracis SNE2.2, B. cereus E1.AB1.2, B. cereus E1AB2.1, Enterobacter cloacae subsp. dissolvens TLE2.2 and S. marcescens KLE3.3. The purposed of this study is to test the ability of the endophytic bacteria strains in increasing defense related enzyme activities of tomato. Bacterial strains were tested for its ability to induce the defense-related enzymes which were phenylalanine ammonia lyase (PAL), peroxidase (PO) and polyphenol oxidase (PPO) in roots and leaves of tomato plants. R. syzigii subsp. indonesiensis inoculated to host plants 7 days after the endophyte bacteria strains inoculation. Enzyme activities were recorded at 0, 1, 3, 5, 7, 9, 12 and 15 days after pathogen inoculation (dpi). It was observed that PAL, PO and PPO activities were significantly increased in all of the endophytic bacteria inoculated treatments compared to control plant. Activities of PAL in the leaves was fast similar to the roots; but PO activities was higher in the roots compared to that in the leaves, whereas PPO activities was higher in the leaves than in the roots. PAL and PO reached the maximum level at different time in the leaves (3 dpi and 15 dpi), in the roots (5 dpi and 12 dpi), whereas PPO in the leaves at 12 dpi and in the roots at 9 dpi.

Thymol and acibenzolar-s-methyl reduce incidence and severity of bacterial wilt of tomato caused by race I biovar III (R1B3) strain of Ralstonia solanacearum in Nigeria

In Nigeria, most strains of Ralstonia solanacearum, the causative agent of tomato bacterial wilt disease; belong to race 1 biovar III (RIB3). Control strategies to assuage its destructive effect are highly necessary. A randomised complete-block design (RCBD) was used for the experiment. Thymol (0.7%) and Acibenzolar-s-methyl (ASM, 30 and 15 µg/ml) were used. Results indicated that the combination of thymol and ASM recorded the highest numbers of days for fruiting in Beske which were 74 and 75 while 59 and 60 days were recorded for UC82-B in both early and late seasons, respectively. When thymol and/or ASM were applied, bacterial wilt disease incidence and disease severity were significantly reduced and this was translated to a significant yield increase when compared with the untreated control plots. The results suggested that the combined application of thymol and ASM could be advantageous to tomato-growing farmers where R. solanacearum is prevalent.

Genetics of tolerance to bacterial wilt disease in tomato (Solanum lycopersicum L.)

Tomato production in the Gangetic plains of eastern India is threatened by high incidence of bacterial wilt (BW) disease caused by Ralstonia solanacearum. Understanding the genetic control of tolerance through utilization of tolerant genotype is the prerequisite to frame effective resistant breeding strategy. Genetic control of host tolerance to BW disease was studied employing six generations (P1, P2, F1, F2, BC1, BC2) of two crosses between one tolerant (Utkal Kumari) and two susceptible (CLN-2498D and CLN-2777F) genotype(s) in presence of the predominant virulent strain (Biovar IIIA) of Ralstonia solanacearum through χ2 test and generation mean analysis. It emerged that tolerance to BW disease was conditioned predominantly by single dominant gene in two Tolerant × Susceptible crosses however, significance of scaling tests revealed involvement of duplicate epistasis suggesting somewhat complex inheritance pattern for the tolerance. Area under disease progress-curve (AUDPC) suggested that cumulative disease progress was less in tolerant genotypes of segregating generations. Duplicate epistasis controlling BW disease incidence suggested mild selection intensity in earlier generation, while intense in later generations of the segregating population in tomato. In this situation, modified bulk method of selection is recommended, in which selection is performed after attaining the homozygosity for maximum heterozygous loci. However, development of hybrids involving at least one tolerant parent is the best option for breeding tomato against BW disease.

Rhizobacteria Suppress Fusarium wilt and Early Blight Diseases in Tomato Grown with Organic Fertilizers

Due to the established toxic effects of agrochemical accumulation in humans, there is an increasing demand for organic agricultural production in Nigeria. The production of highly nutritious and daily consumed crops like tomato through organic farming (using biosupplements) would go a long way in reducing the risks associated with the consumption of inorganic pesticides and fertilizers. In order to investigate the effects of rhizobacterial biosupplement on the resistance and yield of tomato grown with organic fertilizers, the predominant rhizosphere bacteria associated with healthy tomato isolated in this study (Bacillus thuringiensis, Pseudomonas aeruginosa, Bacillus subtilis, Bacillus macerans and Bacillus cereus) were added as a consortium to improve the availability of organic nutrients to plants. Performance measures including the numbers of fruit, branches, leaves, plant height, days to first flowering and days to 50% flowering at 20.00, 17.67, 176.33, 73.33 cm, 70.43 and 78.00 were all better (higher or lower) in treated tomato plants than untreated set. A significant reduction in percentage prevalence was recorded for Fusarium wilt, as well as Early blight diseases on treated plants (seed treatment with rhizobacterial consortium) compared to plants grown from untreated seeds. However, seed treatment appeared to be less effective in the treatment of Bacterial wilt disease of tomato, with percentage prevalence of 41.70 and 42.90 recorded for treated and untreated plants at nine weeks after planting respectively. It could be concluded that the application of rhizobacterial consortium (as seed treatment) improved the yield and resistance of tomato to Fusarium wilt and Early blight diseases caused by Fusarium oxysporum and Alternaria solani respectively.

Outbreak of tomato wilt caused by Ralstonia solanacearum in Tamil Nadu, India and elucidation of its genetic relationship using multilocus sequence typing (MLST)

High incidence of wilt disease (35–45%) of tomato (Solanum lycopersicum L.) was recently observed in two different locations of Tamil Nadu state of India. Infected plants showed typical wilt symptoms which include sudden green wilting of foliage followed by drooping of leaves downwards. The characteristic white milky ooze observed on the cut end of infected stem indicated bacterial etiology. Upon isolation, bacterium produced white fluidal irregular colonies with characteristic pink center on 2, 3, 5 triphenyl tetrazolium chloride amended nutrient medium. The bacterium caused typical green wilting 4–5 days post inoculation (dpi) on one month old tomato plants. The identity of bacterium was confirmed as Ralstonia solanacearum using 16S rRNA gene sequences as well as by R. solanacearum specific PCR. Further studies confirmed that the bacterium belonged to race 1 and biovar 3. In depth genetic characterization using multilocus sequence typing (MLST) revealed that the wilt outbreaks in Tamil Nadu were caused by genetically distinct race 1 strains of R. solanacearum. While the isolate, TRsR found clustered with R. solanacearum isolates previously reported from Andaman and Nicobar Islands-India, TRsP is clustered with isolates reported from Kerala, India. The results of our MLST based genetic analysis clearly indicated horizontal spread of bacterial wilt disease of tomato as a consequence of pathogen migration with the expansion of cultivation in India.

A mathematical model for the dynamics and MCMC analysis of tomato bacterial wilt disease

In this paper, we formulate and analyze a mathematical model to investigate the transmission dynamics of tomato bacterial wilt disease (TBWD) in Mukono district, Uganda. We derive the basic reproduction number [Formula: see text] and prove the existence of a disease-free equilibrium point which is globally stable if [Formula: see text] and an endemic equilibrium which exists if [Formula: see text]. Model parameters are estimated using the Markov Chain Monte Carlo (MCMC) methods and robustness tested. The model parameters were observed to be identifiable. Numerical simulations show that soil solarization and sensitization of farmers can help to eliminate the disease in Uganda. A modified tomato bacterial wilt model with control terms is formulated.

Breeding tomato (Solanum lycopersicum L.) for resistance to biotic and abiotic stresses

Tomato (Solanum lycopersicum L.) is an important vegetable crop cultivated in the tropical and sub-tropical regions of the world. Low productivity in India is due to occurrence of both biotic and abiotic stresses. Among the biotic stresses, tomato leaf curl disease, bacterial wilt, early blight and Groundnut Bud Necrosis Virus disease have become serious production constraints causing considerable yield loss in the major tomato growing areas of the country. Adoption of multiple disease resistant varieties or F1 hybrids would be the most appropriate way to address these diseases. At ICAR-IIHR, Bengaluru systematic breeding strategies were employed to pyramid genes for resistance to early blight, bacterial wilt and tomato leaf curl diseases and to develop advanced breeding lines& F1 hybrids with triple disease resistance. Stable source of resistance to early blight and bi-partite begomo-virus (Tomato Leaf Curl New Delhi Virus) has been identified in Solanum habrochaites LA-1777. Validation with molecular markers linked to tomato leaf curl virus resistance revealed that LA-1777 carryTy2 and other putative resistant genes. Several high yielding dual purpose hybrids were also developed for fresh market and processing with high level of resistance to multiple diseases. Cherry tomato lines have also been bred for high TSS, total carotenoids, total phenols, flavonoids, vitamin C, acidity and lycopene content. IIHR-249-1, IIHR-2101 (Solanum habrochaites LA-1777), IIHR- 2866 and IIHR-2864 recorded high values for quality parameters like total carotenoids, lycopene, vitamin C, total phenols, flavonoids and TSS. Drought tolerant root stock has been developed by an interspecific cross between S. habrochaites LA-1777 and S. lycopersicum (15 SB SB). Resistant sources have also been identified against Tuta absoluta, a serious insect pest reported from major tomato growing areas in the country in recent time. High temperature tolerant breeding lines are in pipe line.

Root priming with Bacillus spp. against bacterial wilt disease of tomato caused by Ralstonia solanacearum

Bacillus spp. have long been used as biological control organisms against plant bacterial diseases but the mechanisms by which the bacteria confer protection against the pathogens are not properly understood. Among nine strains of Bacillus spp. three of them, viz. NBAII 63 (B. megaterium), NBAII 71 (B. cereus) and NBAII 65 (B. megaterium) were found highly inhibitory against R. solanacearum. These strains of Bacillus spp. produced indole acetic acid (IAA) and siderophore and solubilized the phosphorous. High amount of IAA (174.2 μg/ml) and siderophore (1.32μg/ml) production followed by the highest phosphorous solubilization (53.3 μg/ml) by the strain NBAII 63 were found. These three potential Bacillus strains showed the increased activity of defense related enzymes, viz. peroxidase (PO), polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL) and total phenols in pre treated tomato plants challenged with R. solanacearum. Significant activities of PO, PPO, PAL were observed at 8 days after the treatment of antagonist and declined gradually afterwards. The maximum phenol content (185 μg/g of plant tissue) was observed in the tomato plants whose roots were treated with Bacillus strain 63 at 8 days after inoculation treatment. These Bacillus strains could be used as potential biocontrol agent for the management of bacterial wilt disease of tomato.

Phenotypic and genotypic characterization of Clavibacter michiganensis subsp. michiganensis causing tomato bacterial canker and wilt disease in Turkey

Tomato bacterial canker and wilt disease caused by Clavibacter michiganensis subsp. michiganensis (Cmm) is among one of the major bacterial diseases associated with tomato (Solanum lycopersicum L.) in the western Mediterranean region of Turkey. A total of 118 Cmm isolates were obtained from the petiole and the main vein of leaves of different cultivars of diseased tomato plants, and these isolates were cultured in semiselective medium (mSCM). The identity of Cmm isolates was confirmed through gas chromatography-fatty acid methyl-esters (GC-FAME) analysis and polymerase chain reaction (PCR) using the primers, CMM5 and CMM6. The fatty acid analysis of all the Turkish isolates yielded major components that included anteisoheptadeconic acid (a15:0), palmitic acid (i16:0) and anteisoheptadeconic acid (a17:0); the analysis detected and categorized all the isolates into 10 different FAME groups. Among repetitive element sequence PCR (rep-PCR) analysis, Box primer yielded the most reproducible genomic profiles with band sizes that ranged from ~200 bp to 2 kb. The isolates were also separated into 12 groups by pulsed-field gel electrophoresis (PFGE) after digesting the total genomic DNA with SpeI, a rare cutting enzyme. The genome sizes of the different strains of Cmm were also determined after running unrestricted total genomic DNA, which yielded average values between 3.0 and 3.5 MB. All the Cmm isolates had pCM1 and pCM2 plasmids. This is the first report on the detailed characterization of the Cmm population in Turkey.

Identification and Management Challenges Associated with Ralstonia solanacearum (Smith), Causal Agent of Bacterial Wilt Disease of Tomato in Sub-Saharan Africa.

Tomato is the world's most consumed vegetable crop after potato and it is source of vitamins, minerals, fiber, lycopene, β-carotene and income. Despite its significant importance tomato can heavily be attacked by different pathogens including Ralstonia solanacearum that incites bacteria wilt disease. The disease is very devastating causing a considerable yield loss worldwide. The pathogen can survive in plant debris, infected plants and host weeds and spread from one field to another by irrigation or flood water, soil, farm equipment and workers and weeds which usually grow along waterways and it is difficult to manage due to complication in biology, nature of infestation and wide host range. In areas like the Sub-Saharan Africa where there exists a wide diversity of plant species, the pathogen becomes even more difficult to manage. It is on this basis that this review article, clearly discusses challenges for bacterial wilt disease identification and management in tomato farming systems with respect to the diagnosis methods used, pathogen genetic diversity and host range and pathogen survival mechanisms under different environment. The information will empower the responsible personnel involved in tomato production chain to have clear information about the pathogen and management options available against the disease in Sub-Saharan Africa.

Identification of a Pseudomonas putida as biocontrol agent for tomato bacterial wilt disease

A bacterial isolate, A1, was collected from the rhizosphere soil of cultivated peanuts. Based on its 16S rRNA sequence, this isolate was identified as a Pseudomonas putida strain. On minimal medium supplemented with diverse nutrient substrates, the P. putida A1 strain could use fructose and fructosan, trehalose, and inositol as sole carbon resources. The ability of these four carbon resources, as well as leaf and root exudates, to stimulate cell migration in a chemotaxis assay was investigated. P. putida A1 was labelled with GFP to study colonization on the root surface; this strain was found to aggregate around wound sites. In addition to forming biofilms in vitro, A1 showed antimicrobial activity against several plant pathogenic bacteria, including Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. o. pv. oryzicola, and X. citri subsp. citri. In evaluations of biocontrol potential of tomato bacterial wilt, this isolate delayed the appearance of wilt symptoms for 4days and reduced wilt disease severity. Overall, our results indicate that P. putida A1 could be an effective biocontrol agent for plant soil-borne diseases.

English

Many Gram-negative bacteria use N-acyl-homoserine lactone (AHLs) as quorum sensing (QS) signalling molecules to monitor their population density and to regulate gene expression in a density dependent manner. Recently, it has been shown that AHLs are detected by the plants and they trigger plant defense responses. In this study, N-octanoyl-L-homoserine lactone (C8-HSL) has been used as resistant inducer against bacterial wilt disease of tomato caused by Ralstonia solanacearum. The present investigation focused on the role of defense related enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase and lipoxygenase) in imparting resistance in tomato against R. solanacearum. Activities of these defense enzymes, increased in C8-HSL treated tomato plants, which were challenged with R. solanacearum. The transcripts accumulation studies for these enzymes were carried out using semi-quantitative reverse transcription PCR, with maximum mRNA accumulation in resistant cultivar upon treatment with C8-HSL. Quantitative real time-PCR (qRT-PCR) confirmed the maximum induction of all these four genes in C8-HSL treated plants. However, the expression of defense genes was higher in C8-HSL treated resistant cultivar than that of susceptible cultivar. Therefore, the results support the view that C8-HSL molecule enhances disease protection against R. solanacearum infection in tomato through the activation of defense genes. Key words: N-octanoyl-L-homoserine lactone, Ralstonia solanacearum, tomato, defense genes, quantitative real time-polymerase chain reaction (PCR).

Suppressive Effect of Water Extract from Spent Mushroom Substrate of Pleurotus eryngii against Tomato Bacterial Wilt Disease

Suppressive Effect of Water Extract from Spent Mushroom Substrate of Pleurotus eryngii against Tomato Bacterial Wilt Disease

Water Extract from Spent Mushroom Substrate of Hericium erinaceus Suppresses Bacterial Wilt Disease of Tomato

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 β-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.