Control Of Bacterial Wilt Research Articles

Stimuli-responsive sulfur-containing amino acid functionalized boron nitride nanosheets as nanocarriers via improved adhesion to enhance antibacterial performance against plant diseases

Bacterial wilt caused by Ralstonia solanacearum severely impacts agricultural production, urgently requiring effective control measures. Herein, we designed a strategy via boron nitride nanosheets with enhanced adhesion ability as nanocarriers to improve the antibacterial efficacy of active ingredients. To achieve this, we utilized three sulfur-containing amino acids (SAAs), including methionine (MET), cysteine (CYS), and cystine (CYST) for the simultaneously exfoliation and functionalization of boron nitride nanosheets (BNNS) through mechanochemical method, and compared their structure–activity relationship. The obtained BNNS-SAAs exhibited size around 160–250 nm and thickness near 1.5–2.0 nm. The presence of disulfide bond (S-S) within BNNS-CYS and BNNS-CYST promoted them with the responsiveness by redox stimuli. BNNS-CYST acquired highest functionalization degree of 63.44 % among three BNNS-SAAs. And tea tree essential oil (TTO) loading capacity within BNNS-SAAs was around 36.40–37.11 %. The existence of SAAs within BNNS significantly inhibited the volatilization of TTO via nanoconfinement effect fitting to Logistic model, specially, BNNS-CYST held with slowest release rate among the BN-based carriers, due to the stronger attachment or affinity. Furthermore, BNNS-CYST-TTO exhibited the most excellent synergistic antibacterial effect with the increased inhibition zone diameter by 26.89 % against Ralstonia solanacearum in comparison with pure TTO, with the minimum inhibition concentration reduced from 1.8 mg·mL−1 to 0.6 mg·mL−1. The enhanced antibacterial mechanism was proposed based on physical disruption via strong adhesion. BNNS-SAAs also presented superior adhesion and wettability on seed and foliar surfaces, and also promoted seed germination by providing more S nutrients, and exhibited no significant cytotoxicity. Our system provides a green and effective platform response to redox stimuli to load and release essential oils for application in bacterial wilt control.

A Mitogen-Activated Protein Kinase Pathway Is Required for Bacillus amyloliquefaciens PMB05 to Enhance Disease Resistance to Bacterial Soft Rot in Arabidopsis thaliana.

When a plant is infected by a pathogen, endogenous immune responses are initiated. When the initiation of these defense responses is induced by a pathogen-associated molecular pattern (PAMP) of a pathogen, it is called PAMP-triggered immunity (PTI). Previous studies have shown that Bacillus amyloliquefaciens PMB05 can enhance PTI signals and improve disease control of bacterial soft rot and wilt in Arabidopsis thaliana. In the context of controlling bacterial wilt disease, the involvement of a mitogen-activated protein kinase (MAPK) signaling pathway has been established. Nevertheless, it remains unclear whether this pathway is also required for B. amyloliquefaciens PMB05 in controlling bacterial soft rot. In this study, A. thaliana ecotype Columbia (Col-0) and its mutants on a MAPK pathway-related pathway were used as a model and established that the ability of B. amyloliquefaciens PMB05 to control soft rot requires the participation of the MAPK pathway. Moreover, the enhancement of disease resistance by PMB05 is highly correlated with the activation of reactive oxygen species generation and stomata closure, rather than callose deposition. The spray inoculation method was used to illustrate that PMB05 can enhance stomatal closure, thereby restricting invasion by the soft rot bacterium. This control mechanism has also been demonstrated to require the activation of the MAPK pathway. This study demonstrates that B. amyloliquefaciens PMB05 can accelerate stomata closure via the activation of the MAPK pathway during PTI, thereby reducing pathogen invasion and achieving disease resistance against bacterial soft rot.

Integrated genomic and functional analysis of Streptomyces sp. UP1A-1 for bacterial wilt control and solanaceae yield increase

Ralstonia solanacearum is one of the most destructive soil-borne pathogen, causing bacterial wilt to the solanaceae vegetables. Streptomyces sp. UP1A-1 isolated from healthy solanaceae rhizosphere soil, exhibited the lowest disease incidence and increased fruit yield of solanaceae vegetables. However, the genomic and functional properties of UP1A-1 are unclear. Therefore, we conducted the present study to elucidate the genomic characteristics of UP1A-1 by whole genome sequencing. The results indicate that the genome of Streptomyces sp. UP1A-1 consists of 8,252,902 bp and contains 72.42 % G + C. We identified the genes that confer plant growth promoting (PGP) function, which include those involved in siderophore production, indole-3-acetic acid biosynthesis, phosphate solubilization, nitrogen metabolism, and potassium metabolism. We also identified several other genes, such as chitinase, peroxidase, superoxide dismutase, catalase, proline biosynthesis, and glucose dehydrogenase, which are believed to be involved in the control of wilt disease. These genes revealed that the strain UP1A-1 has physiologically adapted to varied environmental conditions and could potentially control both abiotic and biotic stresses.

The Isolation, Identification and Efficacy of Bacillus velezensis XF-8 in Tomato bacterial Wilt Control

The Isolation, Identification and Efficacy of Bacillus velezensis XF-8 in Tomato bacterial Wilt Control

Application of Endophytic Bacteria from Tomato Stems to Control Bacterial Wilt Disease in Tomato and Enhance Plant Growth

Application of Endophytic Bacteria from Tomato Stems to Control Bacterial Wilt Disease in Tomato and Enhance Plant Growth

Isolation and identification of NEAU-CP5: A seed-endophytic strain of B. velezensis that controls tomato bacterial wilt

Bacterial wilt of tomato caused by Ralstonia solanacearum is a critical soilborne disease that drastically reduces yield. In the current study, an endophytic strain NEAU-CP5 with strong antagonistic activity against R. solanacearum was isolated from tomato seeds and characterized. The strain was identified as Bacillus velezensis based on 16S rRNA gene and whole genome sequence analysis. NEAU-CP5 can secrete amylase, protease, and cellulase, and also produce known antibacterial metabolites, including cyclo (leucylprolyl), cyclo (phenylalanyl-prolyl), cyclo (Pro-Gly), 3-benzyl-2,5-piperazinedione, pentadecanoic acid, eicosane, 2-methyoic acid, isovaleric acid, dibuty phthalate, and esters of fatty acids (HFDU), which may be responsible for its strong antibacterial activity. Fourteen gene clusters associated with antibacterial properties were also identified in the whole genome sequence of NEAU-CP5. Pot experiment demonstrated that the application of 108 CFU/mL NEAU-CP5 on tomato plants significantly reduced the incidence of tomato bacterial wilt by 68.36 ± 1.67 %. NEAU-CP5 also increased the activity of defense-related enzymes (CAT, POD, PPO, SOD, and PAL) in tomato plants. This is the first report of an effective control of bacterial wilt on tomato plants by B. velezensis and highlights the potential of NEAU-CP5 as a potential biocontrol agent for the management of tomato bacterial wilt.

G-C3N4@CuO electrostatic self-assembly toward Ralstonia solanacearum: Insights from cytomembrane and motility disruption.

Ralstonia solanacearum, a notorious and refractory bacterial plant pathogen, threatens multiple vegetable crops and causes significant economic loss in agriculture. Long-term use of traditional medicines not only increases the problem of drug resistance, but also causes great environmental pollution. Therefore, there is an urgent need to develop new agents with high efficacy and low toxicity. In this study, we have synthesized and characterized graphitic carbon nitride incorporated copper oxide composite (g-C3N4@CuO), which showed higher antimicrobial effect than graphitic carbon nitride nanosheets (g-C3N4 nanosheets) and copper oxide nanoparticles (CuONPs). Ralstonia solanacearum exposed to g-C3N4@CuO exhibited higher levels of oxygen toxicity, cell membrane damage, DNA damage, motility disruption and even cell death compared to g-C3N4 nanosheets and CuONPs. In addition, g-C3N4@CuO was more effective in the control of tobacco bacterial wilt than g-C3N4 nanosheets and CuONPs. Thus, this study provides a new perspective on g-C3N4@CuO control of bacterial diseases in crops, and the mechanism is related to the destruction of cell membrane damage and motility disruption. © 2024 Society of Chemical Industry.

The Win-Win Effects of an Invasive Plant Biochar on a Soil-Crop System: Controlling a Bacterial Soilborne Disease and Stabilizing the Soil Microbial Community Network.

Biochar is increasingly being recognized as an effective soil amendment to enhance plant health and improve soil quality, but the complex relationships among biochar, plant resistance, and the soil microbial community are not clear. In this study, biochar derived from an invasive plant (Solidago canadensis L.) was used to investigate its impacts on bacterial wilt control, soil quality, and microbial regulation. The results reveal that the invasive plant biochar application significantly reduced the abundance of Ralstonia solanacearum in the soil (16.8-32.9%) and wilt disease index (14.0-49.2%) and promoted tomato growth. The biochar treatment increased the soil organic carbon, nutrient availability, soil chitinase, and sucrase activities under pathogen inoculation. The biochar did not influence the soil bacterial community diversity, but significantly increased the relative abundance of beneficial organisms, such as Bacillus and Sphingomonas. Biochar application increased the number of nodes, edges, and the average degree of soil microbial symbiotic network, thereby enhancing the stability and complexity of the bacterial community. These findings suggest that the invasive plant biochar produces win-win effects on plant-soil systems by suppressing soilborne wilt disease, enhancing the stability of the soil microbial community network, and promoting resource utilization, indicating its good potential in sustainable soil management.

Effects of the invasion of Ralstonia solanacearum on soil microbial community structure in Wuhan, China.

This study investigated the change in the microbiome of tomato rhizosphere soils after the invasion of Ralstonia solanacearum and analyzed the correlation between microbes and soil physicochemical properties. Diversity analyses of the bacteria in healthy and diseased rhizosphere soil samples (HRS and DRS) revealed that HRS had a higher species diversity and were compositionally different from DRS (P ≤ 0.05). Substantial differences in the relative abundance of Actinobacteria (37.52% vs 28.96%, P ≤ 0.05) and Proteobacteria (29.20% vs 35.59%, P ≤ 0.05) were identified in HRS and DRS, respectively. Taxonomic composition analysis showed ten differentially abundant genera, and seven of them (Gaiella, Roseisolibacter, Solirubrobacter, Kribbella, Acidibacter, Actinomarinicola, and Marmoricola) are more abundant in HRS. Soil pH and enzyme activities were negatively correlated with the abundance of R. solanacearum. The contents of total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkaline nitrogen (alkaline N), available phosphorus (AP), available potassium (AK), NO3-N(NN), NH4+-N (AN), and organic matter (OM) were all significantly increased in DRS. The composition and richness of protozoa in the samples show significant differences. Cephalobus, Acrobeles, Heteromita, norank_Tylenchida, and Rotylenchulus were enriched in DRS. Microbial interaction networks revealed that the HRS networks were more complex than the DRS networks. Overall, the results of this study demonstrate that healthy soil has a more complex microbial community structure and higher enzyme activity, and the invasion of R. solanacearum damages the soil microbial system.IMPORTANCEHow does the invasion of Ralstonia solanacearum affect tomato rhizosphere bacteria and protozoa? Which microbial changes can affect the growth of R. solanacearum? To date, most research studies focus on bacteria, with little research on protozoa, and even less on the synergistic effects between protozoa and bacteria. Here, we analyzed the correlation between tomato rhizosphere bacterial and protozoan communities and soil physicochemical properties during the invasion of R. solanacearum. We found that the diversity and abundance of rhizosphere microorganisms in healthy rhizosphere soil samples (HRS) were significantly higher than those in diseased rhizosphere soil samples (DRS), and there were significant changes in soil pH and enzyme activity. Overall, in this study, the analysis of microbial changes during the invasion of R. solanacearum provides a theoretical basis for the prevention and control of bacterial wilt.

Integration of Rhizobacterial Isolates and Airone Chemical for Effective Management of Bacterial Wilt in Cucumber (Cucumis sativus)

The present study aimed to evaluate the efficacy of integrated disease management strategies against bacterial wilt, caused by Erwinia tracheiphila in cucumber (Cucumis sativus) within a controlled greenhouse environment. A total of 56 E. tracheiphila were recovered from the symptomatic cucumber plants among which 13 were tested highly virulent. Among six rhizobacterial isolates; Pseudomonas flurescens-3 (Pf-3), Pseudomonas putida-5 (Pu-5), Pseudomonas stutzeri-2 (Ps-2), Bacillus subtilis-1 (Bs-1), Bacillus safensis-2 (Bs-2), and Pseudomonas stutzeri-1 (Ps-1), tested in vitro using dual culture technique against extremely virulent strain of E. tracheiphila revealed Pf-3, Pu-5 and Bs-1 significantly reduced its growth. Two separate experiments were performed to investigate the synergistic effects of these PGPRs in combination with Airone chemical (active ingredients; Copper Oxychloride + Copper Hydroxide 20%SC by Swat Agro Chemicals, Pakistan) on disease severity and overall plant growth. In the first experiment, eight treatments were tested in a complete randomized design (CRD) with eight replications, focusing on the combination of Pf-3, Pu-5 and Bs-1. Results revealed that the combined application of Pf-3 and Pu-5 significantly outperformed other treatments, exhibiting substantial improvements in key growth parameters; vine length, number of leaves and branches per plant, and a remarkable reduction in disease severity compared to positive and negative controls. In the second experiment, Pf-3, Pu-5 and Bs-1 and Airone chemical were employed in seed and soil treatments to confer resistance to E. tracheiphila and suppress bacterial wilt. The treatment involving P.u-5 and Bs-1, along with a foliar spray of Airone, recorded the lowest disease severity and an increase in plant growth compared to the positive control. These findings suggest that the synergistic application of PGPR and Airone chemical holds promise for integrated disease management in cucumber, providing effective control of bacterial wilt while promoting plant growth. Moreover, the environmentally friendly nature of rhizobacterial-based formulations underscores their potential as safe alternatives for controlling soil-borne plant pathogens without adverse effects on human health or the environment

An Insight into the Prevention and Control Methods for Bacterial Wilt Disease in Tomato Plants

Continuous cropping is the primary cultivation method in Chinese facility agriculture, and the challenge of it stands as a global issue in soil remediation. Growing tomatoes continuously on the same plot for an extended period can result in outbreaks of tomato bacterial wilt. It is caused by the soil-borne bacterium Ralstonia solanacearum, a widespread plant pathogen that inflicts considerable damage on economically significant crops worldwide. Simultaneously, this plant pathogen proves extremely resilient, as it can adhere to plant residues and persist through the winter, continuing to infect plants in subsequent years. Scientists have dedicated considerable efforts towards finding effective methods to manage this disease. This article delineates the characteristics of tomato bacterial wilt and the various types of pathogenic bacteria involved. It systematically reviews the progress in research aimed at controlling tomato bacterial wilt, encompassing both physical and biological aspects concerning soil and plants. Emphasis is placed on the principles and current applications of these control measures, alongside proposed improvements to address their limitations. It is anticipated that the future of tomato bacterial wilt control will revolve around the development of a novel environmental protection system and efficient control strategies, focusing on microecological management and enhancing tomato resistance against bacterial wilt through breeding.

Biological Control of Potato Bacterial Wilt (Ralstonia solanacearum) Using Selected Plant Extracts

Abstract The current study evaluated the effect of methanol and water extracts of tobacco (Nicotiana tabacum L.), wild marigold (Tagetes minuta L.), and garlic (Allium sativum L.) at 50 mg·mL−1 applied at different frequencies (weekly, biweekly, and monthly) on the control of potato bacterial wilt under field conditions (two growing seasons in 2021). Weekly and biweekly application of methanol extracts from tobacco and wild marigold showed higher efficacy of biological control of the pathogen (58% and 57%) on aerial parts of potato plants than monthly application (48%). In potato tubers, weekly and biweekly application of methanol extracts caused higher biological control efficacy (75.92% and 67.39%) than monthly application (52.49%). Weekly and biweekly application of methanol extracts of tobacco and wild marigold also reduced postharvest infection and postharvest yield losses caused by potato bacterial wilt during the storage period, among other treatments. These experiments conclude that weekly or biweekly application of methanol extract from tobacco and wild marigold at 50 mg·mL−1 is a practical approach to control potato bacterial wilt in the field and storage.

A screening identifies harmine as a novel antibacterial compound against Ralstonia solanacearum.

Ralstonia solanacearum, the causal agent of bacterial wilt, is a devastating plant pathogenic bacterium that infects more than 450 plant species. Until now, there has been no efficient control strategy against bacterial wilt. In this study, we screened a library of 100 plant-derived compounds for their antibacterial activity against R. solanacearum. Twelve compounds, including harmine, harmine hydrochloride, citral, vanillin, and vincamine, suppressed bacterial growth of R. solanacearum in liquid medium with an inhibition rate higher than 50%. Further focus on harmine revealed that the minimum inhibitory concentration of this compound is 120 mg/L. Treatment with 120 mg/L of harmine for 1 and 2 h killed more than 90% of bacteria. Harmine treatment suppressed the expression of the virulence-associated gene xpsR. Harmine also significantly inhibited biofilm formation by R. solanacearum at concentrations ranging from 20 mg/L to 60 mg/L. Furthermore, application of harmine effectively reduced bacterial wilt disease development in both tobacco and tomato plants. Collectively, our results demonstrate the great potential of plant-derived compounds as antibacterial agents against R. solanacearum, providing alternative ways for the efficient control of bacterial wilt.

Research progress in biological control of tomato bacterial wilt.

Bacterial wilt caused by the infection of Ralstonia solanacearum, is one of the most harmful diseases to tomatoes, one of the most important greenhouse vegetables in China. R. solanacearum can survive and remain active in the deep soil for a long time, and the chemical control of tomato bacterial wilt is consequently limited. In this study, we introduced the characteristics of tomato bacterial wilt disease and the types of R. solanacearum, and systematically reviewed the research progresses of biological control methods from the aspects of botanical insecticides, agricultural antibiotics, biocontrol bacteria. We emphatically introduced the principle and current status of these methods, discussed the limitations and the improvement strategies, and prospected a new environmental protection and efficient biological control system based on micro-ecological regulation would be the development direction of biological control of tomato bacterial wilt.

Bacterial wilt suppressive composts: Significance of rhizosphere microbiome

Composts are often suppressive to several plant diseases, including the devastating bacterial wilt caused by Ralstonia solanacearum. However, the underlying mechanisms are still unclear. Herein, we carried out an experiment with 38 composts collected from different factories in China to study the interlinking among bacterial wilt suppression, the physicochemical properties and bacterial community of the compost, and bacterial community in the rhizosphere of tomato fertilized by compost. Totally 26 composts were suppressive to bacterial wilt, while six composts stimulated the disease. The control efficiency was neither correlated with physicochemical properties (TC, TN, P and K, pH or GI) nor bacterial community of compost, but with rhizosphere bacterial community (r = 0.17, p = 0.016). The control efficiency was also positive correlated with taxa (Rhizobium, Aeromicrobium) known suppressive to R. solanacearum. The mushroom spent or cow manure, from which the two composts were 100% and 77% in control efficiencies against bacterial wilt respectively were subject to a pilot-scale composting reaction. The reproduced composts from mushroom spent or cow manure were only 57% and 23% effective on the control of bacterial wilt, respectively. The analysis of bacterial communities revealed that the relative abundances of R. solanacearum were 28.4% for the control, but only 7.8%-7.9% for compost fertilized tomatoes. The compost from mushroom spent also exerted a strong effect on rhizosphere bacterial community. Taken together, most composts were suppressive to bacterial wilt possibly also by modifying rhizosphere bacterial community towards inhibiting the colonization of R. solanacearum and selecting for beneficial genera of Proteobacteria, Bacteroidetes and Actinobacteria.

Boosting the Biocontrol Efficacy of Bacillus amyloliquefaciens DSBA-11 through Physical and Chemical Mutagens to Control Bacterial Wilt Disease of Tomato Caused by Ralstonia solanacearum.

Bacterial wilt disease of tomato (Solanum lycopersicum L.), incited by Ralstonia solanacearum (Smith), is a serious agricultural problem in India. In this investigation, chemical mutagenic agents (NTG and HNO2 treatment) and ultraviolet (UV) irradiation have been used to enhance the antagonistic property of Bacillus amyloliquefaciens DSBA-11 against R. solanacearum UTT-25 towards an effective management of tomato wilt disease. The investigation established the fact that maximum inhibition to R. solanacearum UTT-25 was exerted by the derivative strain MHNO2-20 treated with nitrous acid (HNO2) and then by the derivative strain MNTG-21 treated with NTG. The exertion was significantly higher than that of the parent B. amyloliquefaciens DSBA-11. These two potential derivatives viz. MNTG-21, MHNO2-20 along with MUV-19, and a wild derivative strain of B. amyloliquefaciens i.e.,DSBA-11 were selected for GC/MS analysis. Through this analysis 18 major compounds were detected. Among the compounds thus detected, the compound 3-isobutyl hexahydropyrrolo (1,2), pyrazine-1,4-dione (4.67%) was at maximum proportion in the variant MHNO2-20 at higher retention time (RT) of 43.19 s. Bio-efficacy assessment observed a record of minimum intensity (9.28%) in wilt disease and the highest bio-control (88.75%) in derivative strain MHNO2-20-treated plants after 30 days of inoculation. The derivative strain MHNO2-20, developed by treating B. amyloliquefaciens with nitrous acid (HNO2), was therefore found to have a higher bio-efficacy to control bacterial wilt disease of tomato under glasshouse conditions than a wild-type strain.

Pseudomonas forestsoilum sp. nov. and P. tohonis biocontrol bacterial wilt by quenching 3-hydroxypalmitic acid methyl ester.

Bacterial wilt caused by Ralstonia solanacearum ranks the second top important bacterial plant disease worldwide. It is also the most important bacterial disease threatening the healthy development of Casuarina equisetifolia protection forest. 3-hydroxypalmitic acid methyl ester (3-OH PAME) functions as an important quorum sensing (QS) signal regulating the expression of virulence genes in R. solanacearum, and has been regarded as an ideal target for disease prevention and control. To screen native microorganisms capable of degrading 3-OH PAME, samples of C. equisetifolia branches and forest soil were collected and cultured in the medium containing 3-OH PAME as the sole carbon source. Bacteria with over 85% degradation rates of 3-OH PAME after 7-day incubation were further separated and purified. As a result, strain Q1-7 isolated from forest soil and strain Q4-3 isolated from C. equisetifolia branches were obtained and identified as Pseudomonas novel species Pseudomonas forestsoilum sp. nov. and P. tohonis, respectively, according to whole genome sequencing results. The degradation efficiencies of 3-OH PAME of strains Q1-7 and Q4-3 were 95.80% and 100.00% at 48 h, respectively. Both strains showed high esterase activities and inhibited R. solanacearum exopolysaccharide (EPS) and cellulase production. Application of strains Q1-7 and Q4-3 effectively protects C. equisetifolia, peanut and tomato plants from infection by R. solanacearum. Findings in this study provide potential resources for the prevention and control of bacterial wilt caused by R. solanacearum, as well as valuable materials for the identification of downstream quenching genes and the research and development of quenching enzymes for disease control.

Loop-mediated isothermal amplification (LAMP)/Cas12a assay for detection of Ralstonia solanacearum in tomato.

Introduction: Bacterial wilt (BW) caused by the aerobic, Gram-negative pathogenic species Ralstonia solanacearum (RS) is a major disease impacting commercial agriculture worldwide. Asian phylotype I of RS is the cause of tomato bacterial wilt, which has caused severe economic losses in southern China for many years. An urgent priority in control of bacterial wilt is development of rapid, sensitive, effective methods for detection of RS. Methods: We describe here a novel RS detection assay based on combination of loop-mediated isothermal amplification (LAMP) and CRISPR/Cas12a. crRNA1, with high trans-cleavage activity targeting hrpB gene, was selected out of four candidate crRNAs. Two visual detection techniques, involving naked-eye observation of fluorescence and lateral flow strips, were tested and displayed high sensitivity and strong specificity. Results and Discussion: The LAMP/Cas12a assay accurately detected RS phylotype Ⅰ in 14 test strains, and showed low detection limit (2.0 × 100 copies). RS in tomato stem tissue and soil samples from two field sites with suspected BW infection was identified accurately, suggesting potential application of LAMP/Cas12a assay as point-of-care test (POCT). The overall detection process took less than 2 h and did not require professional lab equipment. Our findings, taken together, indicate that LAMP/Cas12a assay can be developed as an effective, inexpensive technique for field detection and monitoring of RS.

Analysis of endophytic bacterial flora of mulberry cultivars susceptible and resistant to bacterial wilt using metagenomic sequencing and culture-dependent approach

Endophytes have a wide range of potential in maintaining plant health and sustainable agricultural environmental conditions. In this study, we analysed the diversity of endophytic bacteria in four mulberry cultivars with different resistance capacity against bacterial wilt using metagenomic sequencing and culture-dependent approaches. We further assessed the role of 11 shared genera in the control of bacterial wilt of mulberry. The results of the present study showed that Actinobacteria, Firmicutes, and Proteobacteria were the three dominant phyla in all communities, with the representative genera Acinetobacter and Pseudomonas. The diversity analysis showed that the communities of the highly and moderately resistant varieties were more diverse compared to those of the weakly resistant and susceptible varieties. The control tests of mulberry bacterial wilt showed that Pantoea, Atlantibacter, Stenotrophomonas, and Acinetobacter were effective, with a control rate of over 80%. Microbacterium and Kosakonia were moderately effective, with a control rate between 50 and 80%. At the same time, Escherichia, Lysinibacillus, Pseudomonas, and Rhizobium were found to be less effective, with a control rate of less than 40%. In conclusion, this study provides a reasonable experimental reference data for the control of bacterial wilt of mulberry.

Control of Bacterial Wilt (Ralstonia solanacearum) and Reduction of Ginger Yield Loss through Integrated Management Methods in Southwestern Ethiopia

Background: Bacterial wilt incited by Ralstonia solanacearum is the most important disease affecting ginger production in southwestern Ethiopia. The unavailability of disease-free planting materials, resistant cultivars, and effective chemical compounds are the key constraints in managing the disease. Objective: The study was initiated to determine the effect of integrated management methods on bacterial wilt disease and yield loss of ginger through combining hot water, bio-fumigation, soil-solarization and chemical pesticides. Methods: A total of seven treatment combinations comprising hot water, bio-fumigation, soil-solarization, Mancozeb, and bleaching powder were tested in a randomized complete block design in three replications. Data on disease incidence, growth, yield, and yield components were recorded from randomly selected plants. Results: The use of Mancozeb for seed socking and soil drenching combined with bio-fumigation and soil-solarization reduced the incidence of bacterial wilt by 63.3% and enhanced the rhizome yield by 66.8%. Rhizome and soil treatment using bleaching powder along with soil bio-fumigation also reduced the disease incidence by 38.9% and increased ginger yield by 61.5%. It also provided the highest (6678.7%) marginal rate of return of any treatment combination tested in the experiment. Disease incidence was highly significantly and inversely (r= -0.98**) correlated with rhizome yield. The regression slope estimated that 83.4% of ginger yield loss was associated with bacterial wilt disease. Conclusion: A combined application of Mancozeb, bio-fumigation and soil-solarization can be used to control ginger bacterial wilt. Alternatively, bleaching powder for rhizome and soil treatment in conjunction with bio-fumigation can be employed as an integrated management system against the disease.