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Baoan Song - One of the best experts on this subject based on the ideXlab platform.
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antiBacterial activities against rice Bacterial leaf blight and tomato Bacterial Wilt of 2 mercapto 5 substituted 1 3 4 oxadiazole thiadiazole derivatives
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Pei Li, Xia Yang, Deyu Hu, Baoan SongAbstract:In this study, a series of 2-mercapto-5-substituted-1,3,4-oxadiazole/thiadiazole derivatives were synthesized and evaluated for their antiBacterial activities against rice Bacterial leaf blight and tomato Bacterial Wilt caused by Xanthomonas oryzae pv. oryzae ( Xoo ) and Ralstonia solanacearum ( R. solanacearum ) via the turbidimeter test in vitro. AntiBacterial bioassays indicated that most compounds demonstrated appreciable antiBacterial bioactivities against Xoo and R. solanacearum . Among the title compounds, compound 4i demonstrated the best inhibitory effect against Xoo and R. solanacearum with half-maximal effective concentration (EC 50 ) values of 14.69 and 15.14 μg/mL, respectively, which were even better than those of commercial agents Bismerthiazol and Thiodiazole Copper. In vivo antiBacterial activities tests under greenhouse conditions revealed that the control efficiency of compound 4i against rice Bacterial leaf blight and tobacco Bacterial Wilt were better than those of Bismerthiazol and Thiodiazole Copper. Meanwhile, field trials also indicated that compound 4i demonstrated appreciable control efficiency against rice Bacterial leaf blight and tomato Bacterial Wilt.
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antiBacterial activities against rice Bacterial leaf blight and tomato Bacterial Wilt of 2 mercapto 5 substituted 1 3 4 oxadiazole thiadiazole derivatives
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Li Shi, Manni Gao, Xia Yang, Wei Xue, Linhong Jin, Baoan SongAbstract:In this study, a series of 2-mercapto-5-substituted-1,3,4-oxadiazole/thiadiazole derivatives were synthesized and evaluated for their antiBacterial activities against rice Bacterial leaf blight and tomato Bacterial Wilt caused by Xanthomonas oryzae pv. oryzae (Xoo) and Ralstonia solanacearum (R. solanacearum) via the turbidimeter test in vitro. AntiBacterial bioassays indicated that most compounds demonstrated appreciable antiBacterial bioactivities against Xoo and R. solanacearum. Among the title compounds, compound 4i demonstrated the best inhibitory effect against Xoo and R. solanacearum with half-maximal effective concentration (EC50) values of 14.69 and 15.14μg/mL, respectively, which were even better than those of commercial agents Bismerthiazol and Thiodiazole Copper. In vivo antiBacterial activities tests under greenhouse conditions revealed that the control efficiency of compound 4i against rice Bacterial leaf blight and tobacco Bacterial Wilt were better than those of Bismerthiazol and Thiodiazole Copper. Meanwhile, field trials also indicated that compound 4i demonstrated appreciable control efficiency against rice Bacterial leaf blight and tomato Bacterial Wilt.
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inhibition of tobacco Bacterial Wilt with sulfone derivatives containing an 1 3 4 oxadiazole moiety
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Feifei Han, Song Yang, Baoan SongAbstract:A series of new sulfone compounds containing the 1,3,4-oxadiazole moiety were designed and synthesized. Their structures were identified by 1H and 13C nuclear magnetic resonance and elemental analyses. AntiBacterial bioassays indicated that most compounds exhibited promising in vitro antiBacterial bioactivities against tobacco Bacterial Wilt at 200 μg/mL. The relationship between structure and antiBacterial activity was also discussed. Among the title compounds, 5′c, 5′h, 5′i, and 5′j could inhibit mycelia growth of Ralstonia solanacearum in vitro by approximately 50% (EC50) at 39.8, 60.3, 47.9, and 32.1 μg/mL, respectively. Among them, compound 5′j was identified as the most promising candidate due to its stronger effect than that of Kocide 3000 [Cu(OH)2] within the same concentration range. Field trials demonstrated that the control effect of compound 5′j against tobacco Bacterial Wilt was better than that of the commercial bactericide Saisentong. For the first time, the present work demonstrated that s...
Hafiz Abdul Samad Tahir - One of the best experts on this subject based on the ideXlab platform.
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bacillus volatiles adversely affect the physiology and ultra structure of ralstonia solanacearum and induce systemic resistance in tobacco against Bacterial Wilt
Scientific Reports, 2017Co-Authors: Hafiz Abdul Samad Tahir, Qin Gu, Huijun WuAbstract:Bacillus volatiles adversely affect the physiology and ultra-structure of Ralstonia solanacearum and induce systemic resistance in tobacco against Bacterial Wilt
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bacillus volatiles adversely affect the physiology and ultra structure of ralstonia solanacearum and induce systemic resistance in tobacco against Bacterial Wilt
Scientific Reports, 2017Co-Authors: Hafiz Abdul Samad Tahir, Yuedi Niu, Rong Huo, Xuewen GaoAbstract:Volatile organic compounds (VOCs) produced by various bacteria have significant potential to enhance plant growth and to control phytopathogens. Six of the most effective antagonistic Bacillus spp. were used in this study against Ralstonia solanacearum (Rsc) TBBS1, the causal agent of Bacterial Wilt disease in tobacco. Bacillus amyloliquefaciens FZB42 and Bacillus artrophaeus LSSC22 had the strongest inhibitory effect against Rsc. Thirteen VOCs produced by FZB42 and 10 by LSSC22 were identified using gas chromatography-mass spectrometry analysis. Benzaldehyde, 1,2-benzisothiazol-3(2 H)-one and 1,3-butadiene significantly inhibited the colony size, cell viability, and motility of pathogens and negatively influenced chemotaxis. Transmission and scanning electron microscopy revealed severe morphological and ultra-structural changes in cells of Rsc. Furthermore, VOCs altered the transcriptional expression level of PhcA (a global virulence regulator), type III secretion system (T3SS), type IV secretion system (T4SS), extracellular polysaccharides and chemotaxis-related genes, which are major contributors to pathogenicity, resulting in decreased Wilt disease. The VOCs significantly up-regulated the expression of genes related to Wilt resistance and pathogen defense. Over-expression of EDS1 and NPR1 suggest the involvement of SA pathway in induction of systemic resistance. Our findings provide new insights regarding the potential of antiBacterial VOCs as a biocontrol tool against Bacterial Wilt diseases.
Qirong Shen - One of the best experts on this subject based on the ideXlab platform.
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biofertilizer application triggered microbial assembly in microaggregates associated with tomato Bacterial Wilt suppression
Biology and Fertility of Soils, 2020Co-Authors: Menghui Dong, Zongzhuan Shen, Xuhui Deng, Yannan Ou, Mengli Zhao, Rong Li, Qirong ShenAbstract:Soil aggregates support diverse microbes due to heterogeneous micro-environment. A lot of researches have exhibited the difference of microbial composition and activity within different size soil aggregates, but the relative influences of these microbes and the mechanisms underlying their effects on plant health are still poorly understood. This study investigated the microbiomes within four soil aggregate fractions sampled from fields with different incidences of tomato Bacterial Wilt derived from three fertilization regimes (organic, bio-organic and chemical) and un-fertilized soil to decipher the mechanisms involved in disease suppression. A wet-sieving method was used to separate the aggregate fractions; Illumina MiSeq sequencing was used to characterize the soil microbiomes in field experiment, and real-time qPCR analysis was used in lab cultivation experiment to quantify the number of pathogens. Organic fertilization (OF) and bio-organic fertilization (BF) significantly decreased disease incidences compared with the effects of treatments with chemical fertilizer (CF) and those without fertilizer (CK). The microbial composition was significantly different between fertilizations and aggregate fractions; particularly, the Bacterial composition was significantly correlated with disease incidence. Different aggregate fractions contained disparate Bacterial taxa correlated with disease incidence. Only in the microaggregate (Mi), the Ralstonia genus’ relative abundance showed a significant and positive correlation with disease incidence. The lab cultivation experiment demonstrated that after a spiking of Ralstonia solanacearum, whole soil and the Mi from BF-treated soil showed a significant higher resistance against pathogen invasion than those from CF-treated soil. The correlation between pathogen abundance and disease incidence in the field experiment and the higher resistance of Mi fraction against pathogen indicates that the microaggregates are the key fraction for suppressing tomato Bacterial Wilt in bio-organic fertilization practice, providing novel insight into the manipulation of the soil microbiome.
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rhizobacterium bacillus amyloliquefaciens strain sqrt3 mediated induced systemic resistance controls Bacterial Wilt of tomato
Pedosphere, 2017Co-Authors: L I Chunyu, H U Weicong, Bin Pan, Yan Liu, Saifei Yuan, Yuanyuan Ding, L I Rong, Xinyan Zheng, Biao Shen, Qirong ShenAbstract:Abstract Tomato Bacterial Wilt caused by Ralstonia solanacearum seriously threats tomato growth in tropical and temperate regions around the world. This study reported an antagonistic Bacterial strain, Bacillus amyloliquefaciens strain SQRT3, isolated from the rhizosphere soil of tomato plants, which strongly inhibited in vitro growth of pathogenic R. solanacearum. The suppression of tomato Bacterial Wilt by strain SQRT3 was demonstrated under greenhouse conditions. Additionally, induced systemic resistance (ISR) in tomato as one of the potential disease suppression mechanisms was investigated in the plants inoculated with the isolated Bacterial strain SQRT3. The results showed that strain SQRT3 applied with R. solanacearum by drenching significantly reduced tomato Bacterial Wilt by 68.1% biocontrol efficiency (BE) and suppressed the R. solanacearum populations in the rhizosphere soil compared to the control only drenched with R. solanacearum. The BE of the isolated Bacterial strain SQRT3 against tomato Wilt increased to 84.1% by root-dipping. Tomato plants treated with both strain SQRT3 and R. solanacearum showed increases in activities of peroxidase and polyphenol oxidase compared with other treatments. The application of strain SQRT3 reduced membrane lipid peroxidation in tomato leaves. The expressions of marker genes for jasmonic acid- and salicylic acid-dependent signaling pathways were faster and stronger in tomato plants treated with both strain SQRT3 and R. solanacearum than in plants treated with either R. solanacearum or strain SQRT3 alone. Collectively, the findings indicated that strain SQRT3 can effectively control tomato Wilt.
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effects of bio organic fertilizer plus soil amendment on the control of tobacco Bacterial Wilt and composition of soil Bacterial communities
Biology and Fertility of Soils, 2014Co-Authors: Saifei Yuan, Biao Shen, Lili Wang, Junxiong Shi, Jun Zhao, Qirong ShenAbstract:Tobacco Bacterial Wilt (TBW) is caused by Ralstonia solanacearum (R. solanacearum), a severe pathogenic agent with a wide host range. In this study, lime + ammonium bicarbonate (L + AB), organic fertilizer (OF), bio-organic fertilizer (BOF), and integrated treatment (L + AB + BOF) were assessed for the ability to control TBW and to influence the composition of native soil Bacterial communities. The results showed that disease incidence of L + AB + BOF for two growth seasons in pot experiment was the lowest, with only 15.56 and 11.11 % at seasons 1 and 2, respectively. The integrated treatment could also significantly suppress TBW in the field, with a disease incidence of only 14.27 % compared with 35.41, 50.03, and 31.32 % in L + AB, OF, and BOF treatments, respectively. With application of the integrated treatment in pot and field experiments, the abundances of R. solanacearum were both significantly lower than those with other treatments. Denaturing gradient gel electrophoresis (DGGE) patterns showed that application of BOF significantly affected composition of Bacterial communities of rhizosphere. The analysis of 454 sequencing data showed that application of integrated treatment recruited more beneficial bacteria than other treatments, such as Bacillus, Paenibacillus, Arthrobacter, and Streptomyces, while the abundance of Ralstonia with the integrated treatment was decreased. Overall, these results suggested that application of integrated agricultural management could effectively suppress Bacterial Wilt by affecting the composition of Bacterial community and reducing the population of R. solanacearum.
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evaluation of bacillus fortified organic fertilizer for controlling tobacco Bacterial Wilt in greenhouse and field experiments
Applied Soil Ecology, 2014Co-Authors: Saifei Yuan, Qirong Shen, Lili Wang, Junxiong Shi, Maosheng Wang, Xingming Yang, Biao ShenAbstract:Abstract Bacterial Wilt caused by Ralstonia solanacearum is one of the most serious tobacco diseases worldwide, and no effective control measures are available to date. Three Bacillus isolates ( Bacillus amyloliquefaciens SQR-7 and SQR-101 and Bacillus methylotrophicus SQR-29) were obtained from the rhizosphere soil of tobacco. These bacilli exhibited strong inhibition against R. solanacearum and produced indole acetic acid and siderophores. The three antagonistic strains were used to fortify organic fertilizers to produce bioorganic fertilizers (BOFs named for each isolate) for the control of tobacco Bacterial Wilt. The application of BOFs delayed Wilt development and effectively decreased the disease incidence under both greenhouse and field conditions. The tobacco Bacterial Wilt control efficacy was 44.3%, 70.5%, and 85.1% using BOF101, BOF29, and BOF7 in the greenhouse. Although the control efficacies in the field were lower, the application of BOF7 still achieved 58.0% and 56.2% control efficacies in two years field experiments. The application of bioorganic fertilizer significantly ( p R. solanacearum in soil in both pot and field experiments, though the abundance of R. solanacearum increased as during the growth period of the tobacco plants. In general, the populations of the antagonistic Bacterial strains declined after soil application and as the tobacco plants grew; however, the density of SQR-7 and SQR-29 in the rhizosphere soil remained at a high level (≥10 6 cfu/g) in the later growth stages. Additionally, the application of bioorganic fertilizers promoted tobacco growth and increased the leaf yield.
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evaluation of rhizosphere bacteria and derived bio organic fertilizers as potential biocontrol agents against Bacterial Wilt ralstonia solanacearum of potato
Plant and Soil, 2013Co-Authors: Chuanyu Ding, Qirong Shen, Ruifu Zhang, Wei ChenAbstract:Potato Bacterial Wilt (Ralstonia solanacearum) is a soil-borne disease that affects the potato plant (Solanum tuberosum) worldwide and causes serious economic losses in southern China. The objective of this study is to study the effect of Bacterial antagonists and bio-organic fertilizers on potato Bacterial Wilt and rhizosphere soil microbial population. In the present study, pot and field experiments were conducted to evaluate the LH23 (Bacillus amyloliquefaciens) and LH36 (Bacillus subtilis) strains and their derived bio-organic fertilizers (BIO23 and BIO36) as potential biocontrol agents against potato Bacterial Wilt. BIO23 and BIO36 decreased the incidence of Bacterial Wilt disease and increased potato yields. In pot experiments, the disease incidence of BIO23 and BIO36 was 8.9 % and 11.1 % respectively, much lower than the control (57.7 %). The biocontrol efficiency of BIO23 was 84.6 %, which was the most successful treatment and BIO36 was the second with a biocontrol efficiency of 80.8 %. The increased percentages of potato yields when compared with the control were 63.5 % (BIO23), 64.7 % (BIO36) 34.8 % (LH23), 33.6 % (LH36) and 20.7 % (OF). The counts of antagonists, bacteria and actinobacteria in the rhizosphere soil were significantly increased in BIO23 and BIO36 treatments, whereas the counts of R. solanacearum and fungi in the soil in the both treatments decreased. In field experiments, 70 days after treatment, the biocontrol efficacies of BIO23 and BIO36 treatments were 92.0 % and 84.0 %, and the yield increases of BIO23 and BIO36 treatments were 42.3 % and 28.8 %, respectively, when compared with the organic fertilizer treatment. In addition, the changes in the microbial populations were the same as those observed in the greenhouse experiment. Potato Bacterial Wilt could be well controlled by the application bio-organic fertilizer containing a specific antagonist, mainly through the alternation of soil microbial community
Huijun Wu - One of the best experts on this subject based on the ideXlab platform.
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bacillus volatiles adversely affect the physiology and ultra structure of ralstonia solanacearum and induce systemic resistance in tobacco against Bacterial Wilt
Scientific Reports, 2017Co-Authors: Hafiz Abdul Samad Tahir, Qin Gu, Huijun WuAbstract:Bacillus volatiles adversely affect the physiology and ultra-structure of Ralstonia solanacearum and induce systemic resistance in tobacco against Bacterial Wilt
Caitilyn Allen - One of the best experts on this subject based on the ideXlab platform.
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the in planta transcriptome of ralstonia solanacearum conserved physiological and virulence strategies during Bacterial Wilt of tomato
Mbio, 2012Co-Authors: Jonathan M Jacobs, Lavanya Babujee, Fanhong Meng, Annett Milling, Caitilyn AllenAbstract:Plant xylem fluid is considered a nutrient-poor environment, but the Bacterial Wilt pathogen Ralstonia solanacearum is well adapted to it, growing to 10(8) to 10(9) CFU/g tomato stem. To better understand how R. solanacearum succeeds in this habitat, we analyzed the transcriptomes of two phylogenetically distinct R. solanacearum strains that both Wilt tomato, strains UW551 (phylotype II) and GMI1000 (phylotype I). We profiled Bacterial gene expression at ~6 × 10(8) CFU/ml in culture or in plant xylem during early tomato Bacterial Wilt pathogenesis. Despite phylogenetic differences, these two strains expressed their 3,477 common orthologous genes in generally similar patterns, with about 12% of their transcriptomes significantly altered in planta versus in rich medium. Several primary metabolic pathways were highly expressed during pathogenesis. These pathways included sucrose uptake and catabolism, and components of these pathways were encoded by genes in the scrABY cluster. A UW551 scrA mutant was significantly reduced in virulence on resistant and susceptible tomato as well as on potato and the epidemiologically important weed host Solanum dulcamara. Functional scrA contributed to pathogen competitive fitness during colonization of tomato xylem, which contained ~300 µM sucrose. scrA expression was induced by sucrose, but to a much greater degree by growth in planta. Unexpectedly, 45% of the genes directly regulated by HrpB, the transcriptional activator of the type 3 secretion system (T3SS), were upregulated in planta at high cell densities. This result modifies a regulatory model based on Bacterial behavior in culture, where this key virulence factor is repressed at high cell densities. The active transcription of these genes in Wilting plants suggests that T3SS has a biological role throughout the disease cycle. IMPORTANCE Ralstonia solanacearum is a widespread plant pathogen that causes Bacterial Wilt disease. It inflicts serious crop losses on tropical farmers, with major economic and human consequences. It is also a model for the many destructive microbes that colonize the water-conducting plant xylem tissue, which is low in nutrients and oxygen. We extracted bacteria from infected tomato plants and globally identified the biological functions that R. solanacearum expresses during plant pathogenesis. This revealed the unexpected presence of sucrose in tomato xylem fluid and the pathogen's dependence on host sucrose for virulence on tomato, potato, and the common weed bittersweet nightshade. Further, R. solanacearum was highly responsive to the plant environment, expressing several metabolic and virulence functions quite differently in the plant than in pure culture. These results reinforce the utility of studying pathogens in interaction with hosts and suggest that selecting for reduced sucrose levels could generate Wilt-resistant crops.
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Bacterial Wilt disease and the ralstonia solanacearum species complex
Bacterial wilt disease and the Ralstonia solanacearum species complex., 2005Co-Authors: Caitilyn Allen, Philippe Prior, A C HaywardAbstract:Contents: Preface. Introductory overviews: Research on Bacterial Wilt: a perspective on international linkages and access to the literature; the current Bacterial Wilt situation: a global overview - Epidemiology of Ralstonia solanacearum: introduction and prospectus on the survival of introduction and prospectus on the survival; Fate of Ralstonia solanacearum Biovar 2 as affected by conditions and soil treatments in temperate climate zones; Mechanization has contributed to the spread of Bacterial Wilt on flue-cured tobacco in the Southeastern USA; Processes in the development of a biocontrol agent against Bacterial Wilt; Colonization capacity of Ralstonia solanacearum; Tomato strains differing in aggressiveness on tomatoes and weeds; Introduction to Europe of Ralstonia solanacearum Biovar 2, Race 3 in Pelargonium zonale cuttings from Kenya; Seeds from infected tomato plants appear to be free from contamination by Ralstonia solanacearum when tested by PCR or microbiological assays; The viable but non-culturable state in Ralstonia solanacearum: is there a realistic threat to our strategic concepts? - Bacterial Wilt disease management: Management of Bacterial Wilt disease; Management of Bacterial Wilt in tomato with essential oils and systemic acquired resistance inducers; Monitoring of Bacterial Wilt in potato propagation material: a success story; Integrated control of potato Bacterial Wilt in Eastern Africa: the experience of African highlands initiative; Using Brassica spp. as biofumigants to reduce the population of Ralstonia solanacearum; Seed-plot technique: empowerment of farmers in production of Bacterial Wilt-free seed potato in Kenya and Uganda; Primary Bacterial Wilt study on tomato in vegetable areas of Ho Chi Minh City, Vietnam; Rhizome solarization and microwave treatment: ecofriendly methods for disinfecting ginger seed rhizomes; Management of Bacterial Wilt of potato using one-season rotation crops in South-Western Uganda; Potato Bacterial Wilt management: new prospects for an old problem - Breeding and deployment of Wilt-resistant crops: A broad review and perspective on breeding for resistance to Bacterial Wilt; Progress on genetic enhancement for resistance to groundnut Bacterial Wilt in China; Search for resistance to Bacterial Wilt in a Brazilian Capsicum germplasm collection; Solanum phureja and S. stenotomum are sources of resistance to Ralstonia solanacearum for somatic hybrids of potato; Assessment of resistance to Bacterial Wilt in CIP advanced potato clones; Screening long pepper (Piper spp.) resistance to Bacterial Wilt caused by Ralstonia solanacearum - Host plant response and disease development: Host resistance to Ralstonia solanacearum; Microscopic studies of root infection in resistant tomato cv. Hawaii 7996; Development of Bacterial Wilt resistant varieties and basis of resistance in eggplant (Solanum melongena); QTL mapping for Bacterial Wilt resistance in Hawaii 7996 using AFLP, RGA, and SSR markers; Genetic basis of resistance to Bacterial Wilt in Arabidopsi thaliana; Roles of the Hrp-secreted PopA protein in Ralstonia solanacearum interactions with plants - Pathogen genetics: A short history of the biochemical and genetic research on Ralstonia solanacearum pathogenesis; The Ralstonia solanacearum complete genome sequence: outputs and prospects; Genes involved in early Bacterial Wilt pathogenesis; Phase reversion from phenotype conversion mutants to wild type may be induced in Ralstonia solanacearum by a susceptible host-plant; Insertions in the avirulence gene AvrA alter the virulence of Ralstonia solanacearum on Nicotiana tabacum; Ralstonia solanacearum requires type-4 Pili for twitching motility, adherence, natural transformation and virulence; Understanding the molecular basis of Bacterial Wilt disease: a view from the inside out - R. solanacearum in banana and plantains: Bacterial Wilt diseases of banana: evolution and ecology; Comparative genome plasticity of tomato and banana strains o
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ralstonia solanacearum genes induced during growth in tomato an inside view of Bacterial Wilt
Molecular Microbiology, 2004Co-Authors: Darby G Brown, Caitilyn AllenAbstract:Summary The phytopathogen Ralstonia solanacearum has over 5000 genes, many of which probably facilitate Bacterial Wilt disease development. Using in vivo expression technology (IVET), we screened a library of 133 200 R. solanacearum strain K60 promoter fusions and isolated a 900 fusions expressed during Bacterial growth in tomato plants. Sequence analysis of 307 fusions revealed 153 unique in planta -expressed ( ipx ) genes. These genes included seven previously identified virulence genes ( pehR , vsrB , vsrD , rpoS , hrcC , pme and gspK ) as well as seven additional putative virulence factors. A significant number of ipx genes may reflect adaptation to the host xylem environment; 19.6% ipx genes are predicted to encode proteins with metabolic and/or transport functions, and 9.8% ipx genes encode proteins possibly involved in stress responses. Many ipx genes (18%) encode putative transmembrane proteins. A majority of ipx genes isolated encode proteins of unknown function, and 13% were unique to R. solanacearum . The ipx genes were variably induced in planta ; b b b -glucuronidase reporter gene expression analysis of a subset of 44 ipx fusions revealed that in planta expression levels were between two- and 37-fold higher than in culture. The expression of many ipx genes was subject to known R. solanacearum virulence regulators. Of 32 fusions tested, 28 were affected by at least one virulence regulator; several fusions were controlled by multiple regulators. Two ipx fusion strains isolated in this screen were reduced in virulence on tomato, indicating that gene(s) important for Bacterial Wilt pathogenesis were interrupted by the IVET insertion; mutations in other ipx genes are necessary to determine their roles in virulence and in planta growth. Collectively, this profile of ipx genes suggests that in its host, R. solanacearum confronts and overcomes a stressful and nutrient-poor environment.
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ralstonia solanacearum genes induced during growth in tomato an inside view of Bacterial Wilt
Molecular Microbiology, 2004Co-Authors: Darby G Brown, Caitilyn AllenAbstract:The phytopathogen Ralstonia solanacearum has over 5000 genes, many of which probably facilitate Bacterial Wilt disease development. Using in vivo expression technology (IVET), we screened a library of 133 200 R. solanacearum strain K60 promoter fusions and isolated approximately 900 fusions expressed during Bacterial growth in tomato plants. Sequence analysis of 307 fusions revealed 153 unique in planta-expressed (ipx) genes. These genes included seven previously identified virulence genes (pehR, vsrB, vsrD, rpoS, hrcC, pme and gspK) as well as seven additional putative virulence factors. A significant number of ipx genes may reflect adaptation to the host xylem environment; 19.6%ipx genes are predicted to encode proteins with metabolic and/or transport functions, and 9.8%ipx genes encode proteins possibly involved in stress responses. Many ipx genes (18%) encode putative transmembrane proteins. A majority of ipx genes isolated encode proteins of unknown function, and 13% were unique to R. solanacearum. The ipx genes were variably induced in planta; beta-glucuronidase reporter gene expression analysis of a subset of 44 ipx fusions revealed that in planta expression levels were between two- and 37-fold higher than in culture. The expression of many ipx genes was subject to known R. solanacearum virulence regulators. Of 32 fusions tested, 28 were affected by at least one virulence regulator; several fusions were controlled by multiple regulators. Two ipx fusion strains isolated in this screen were reduced in virulence on tomato, indicating that gene(s) important for Bacterial Wilt pathogenesis were interrupted by the IVET insertion; mutations in other ipx genes are necessary to determine their roles in virulence and in planta growth. Collectively, this profile of ipx genes suggests that in its host, R. solanacearum confronts and overcomes a stressful and nutrient-poor environment.
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Bacterial Wilt disease molecular and ecological aspects
1998Co-Authors: Philippe Prior, Caitilyn Allen, J G ElphinstoneAbstract:One Hundred and One Years of Research on Bacterial Wilt.- Bacterial Wilt: the Missing Element in International Banana Improvement Programs.- Chair's Perspective: Diversity of Ralstonia solanacearum.- Phylogeny, Diversity and Molecular Diagnostics of Ralstonia solanacearum.- Development of a Diagnostic Test Based on the Polymerase Chain Reaction (PCR) to Identify Strains of R. solanacearum Exhibiting the Biovar 2 Genotype.- Genetic Diversity of Ralstonia solanacearum Race 3 in Western Europe determined by AFLP, RC-PFGE and Rep-PCR.- Biogeographic Studies on Ralstonia solanacearum Race 1 and 3 by Genomic Fingerprinting.- Analysis of Genetic Variation of a Population of Banana Infecting Strains of Ralstonia solanacearum.- Genetic Diversity of Ralstonia solanacearum in Japan.- Diversity of Ralstonia solanacearum in Tomato Rhizosphere Soil.- Population Structure of Ralstonia solanacearum From a Disease Nursery and Tomato Production Fields in Taiwan.- Correlation of Aggressiveness with Genomic Variation in Ralstonia solanacearum Race.- Chair's Perspective:.- Molecular Methods for Detection and Discrimination of Ralstonia solanacearum.- Adaptation of Technology for Diagnosis and Detection ofRalstonia solanacearum in Malawi and Tanzania.- Efficiency of a Vacuum Infiltration Inoculation Procedure for Detecting Ralstonia solanacearum in Soil.- Developing Appropriate Detection Methods for Developing Countries.- Evaluation of Methods for Detection of Potato Seed Contamination by Ralstonia solanacearum.- Detection of Ralstonia solanacearum in Potato Tubers, Solanum dulcamara and Associated Irrigation Water.- Selection of Ralstonia solanacearum Race 3 Specific Monoclonal Antibodies from Combinatorial Libraries.- Experiences with Bacterial Brown Rot Ralstonia solanacearum Biovar 2, Race 3 in the Netherlands.- Directions for Future Research on Bacterial Pathogenicity.- Analysis of Extracellular Polysaccharide I In Culture and In Planta Using Immunological Methods: New Insights and Implications.- Regulation of Virulence by Endogenous Signal Molecules and the Importance of Extracellular Polysaccharide During Infection and Colonization.- Function and Regulation of Pectin-Degrading Enzymes in Bacterial Wilt Disease.- The Ralstonia solanacearum hrp Gene Region: Role of the Encoded Proteins in Interactions with Plants and Regulation of Gene Expression.- Relationship of Wild Type Strain Motility and Interaction with Host Plants in Ralstonia solanacearum.- Studies on the Molecular Basis for Pathogenicity and Host Specificity in Strains of Ralstonia solanacearum Pathogenic to Banana.- Chair's Perspective: Host Resistance.- Transcriptional Regulation and Function of hsr203J, an Hypersensitivity-Related Gene of Tobacco Activated in Respons to Ralstonia solanacearum.- An Anti-Ralstonia solanacearum Protein from Potato and Its Immunogold Localization In Vivo.- Involvement of Nitric Oxide in Ralstonia solanacearum-Induced Hypersensitive Reaction in Tobacco.- Correlation of Chemical Profiles of Xylem Fluid of Tomato to Resistance to Bacterial Wilt.- Behavior of Bioluminescent Ralstonia solanacearum YN5 Containing the luxCDABE in Tomatoes Susceptible and Resistant to Bacterial Wilt.- Genetic Analysis of Quantitative Resistance Loci (QRL) of Tomato Variety Hawaii 7996 in Taiwan.- Identification and Mapping of RRS1, a Single Recessive Locus in Arabidopsis thaliana that Confers Resistance to Ralstonia solanacearum.- Mi Introgression Lines as Tools for the Genetic Analysis of Bacterial Wilt Resistance in Tomato.- Genetics of Plant Resistance to Bacterial Wilt: Round Table Report.- Worldwide Evaluation of an International Set of Resistance Sources to Bacterial Wilt in Tomato.- Selection of Processing Tomato Progenies for Resistance to Ralstonia solanacearum.- Resistance Sources to Bacterial Wilt in Eggplant (Solanum melongena).- Breeding for Resistance to Bacterial Wilt of Potatoes in Brazil.- Relationship Between Latent Infection and Groundnut Bacterial Wilt Resistance.- Inheritance of Resistance to Bacterial Wilt in Chinese Dragon Groundnuts.- Resistance to Bacterial Wilt in Uganda.- Multiplication of Ralstonia solanacearum in Capsicum annuum.- Solanum tuberosum - S. commersonii Somatic Hybrids are Resistant to Brown Rot Caused by Ralstonia solanacearum.- Chairs' Perspectives on Biological Control and Epidemiology.- The Suppression of Ralstonia by Marigolds solanacearum.- Elements of Biocontrol of Tomato Bacterial Wilt solanacearum.- The Development of a Biological Control Agent against Ralstonia solanacearum Race 3 in Kenya.- A Tentative Explanation of the Distribution, on Reunion Island, of Bacterial Wilt Caused by Either Biovar 2 or Biovar 3 of Ralstonia solanacearum.- The Effect of Temperature, Storage Period and Inoculum Concentration on Symptom Development and Survival of Ralstonia solanacearum in Inoculated Tubers.- Epidemiology of Tomato Bacterial Wilt in Agreste Region of Pernambuco State, Brazil, in 1996/1997.- Current Situation of Bacterial Wilt (Ralstonia solanacearum Smith) in Cuba.- Factors Affecting the Population of Ralstonia solanacearum in a Naturally Infested Field Planted to Tobacco.- Disease Management Session Commentary.- The Usefulness of Potato Resistance to Ralstonia solanacearum, for the Integrated Control of Bacterial Wilt.- Bacterial Wilt in Brazil: Current Status and Control Methods.- Disease Management Strategies for Control of Bacterial Wilt of Tobacco in the Southeastern USA.- Relative Importance of Latent Tuber Infection and Soil Infestation by Ralstonia solanacearum on the Incidence of Bacterial Wilt of Potato.- Maintaining Scottish Seed Potato Production Free From Ralstonia solanacearum.- Weeds as Latent Hosts of Ralstonia solanacearum in Highland Uganda: Implications to Development of an Integrated Control Package for Bacterial Wilt.- Round Table on Bacterial Wilt (Brown Rot) of Potato.- List of Authors.
