Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strateg...Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strategies to control the disease.As a soilborne pathogen,R.solanacearum naturally infects plants via roots.A huge limitation in studying plant-R.solanacearum interactions is the large variation of R.solanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.Here,we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.This method is easy to use,takes about only 10 days from seed germination to the completion of inoculation assay,and requires less inoculum of bacteria as well as growth chamber space.We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns,resistance of defense-related plant mutants,and virulence of R.solanacearum mutants.Furthermore,we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.展开更多
BACKGROUND Ralstonia is a Gram-negative non-fermentative bacterium widespread in nature,and includes four species,Ralstonia pickettii,Ralstonia solanacearum,Ralstonia mannitolilytica,and Ralstonia insidiosa,which were...BACKGROUND Ralstonia is a Gram-negative non-fermentative bacterium widespread in nature,and includes four species,Ralstonia pickettii,Ralstonia solanacearum,Ralstonia mannitolilytica,and Ralstonia insidiosa,which were proposed in 2003.Ralstonia is mainly found in the external water environment,including municipal and medical water purification systems.This bacterium has low toxicity and is a conditional pathogen.It has been reported in recent years that infections due to Ralstonia are increasing.Previous studies have shown that most cases of infection are caused by Ralstonia pickettii,a few by Ralstonia mannitolilytica,and infections caused by Ralstonia insidiosa are rare.CASE SUMMARY A 2-year-old Chinese child suffered from intermittent fever and cough for 20 d and was admitted to hospital with bronchial pneumonia.Bronchoscopy and alveolar lavage fluid culture confirmed Ralstonia insidiosa pneumonia.The infection was well controlled after treatment with meropenem and azithromycin.CONCLUSION Ralstonia infections are increasing,and we report a rare case of Ralstonia insidiosa infection in a child.Clinicians should be vigilant about Ralstonia infections.展开更多
Silicon(Si) can increase plant resistance against bacterial wilt caused by Ralstonia solanacearum and enhance plant immune response. However, whether Si alleviates soil-borne disease stress through altering soil micro...Silicon(Si) can increase plant resistance against bacterial wilt caused by Ralstonia solanacearum and enhance plant immune response. However, whether Si alleviates soil-borne disease stress through altering soil microbial community component and diversity is not clear. In this study, effects of Si application under R. solanacearum inoculation with or without plant on soil bacterial and fungal communities were investigated through high-throughput pyrosequencing technique. The results showed that Si addition significantly reduced bacterial wilt incidence. However, Si did not reduce the amount of R. solanacearum in rhizosphere soil. Principal components analysis showed that soil microbial community composition was strongly influenced by Si addition. Total 63.7% bacterial operational taxonomic units(OTUs) and 43.8% fungal OTUs were regulated by Si addition regardless of the presence of tomato plants, indicating the independent effects of Si on soil microbial community. Si-added soil harbored a lower abundance of Fusarium, Pseudomonas, and Faecalibacterium. Our finding further demonstrated that exogenous Si could significantly influence soil microbial community component, and this may provide additional insight into the mechanism of Si-enhanced plant resistance against soil-borne pathogens.展开更多
Bacterial wilt, caused by Ralstonia solanacearum（Rs） is a serious soil-borne disease and silicon can enhance tomato resistance against this disease. However, few studies have focused on the mechanisms of Si-mediated...Bacterial wilt, caused by Ralstonia solanacearum（Rs） is a serious soil-borne disease and silicon can enhance tomato resistance against this disease. However, few studies have focused on the mechanisms of Si-mediated pathogen resistance from the rhizosphere perspective. In this study, two tomato genotypes, HYT（susceptible） and H7996（resistant）, were used to investigate the effects of silicon application on disease inhibition, root growth, and organic acid content in both roots and root exudates under R. solanacearum infection. The results showed that Si application significantly suppressed bacterial wilt in HYT, but had no effect in H7996. Silicon concentrations in roots, stems and leaves of tomato were significantly increased by Si treatment under R. solanacearum inoculation. In HYT, Si application increased root dry weight by 22.8-51.6% and leaf photosynthesis by 30.6-208.0%, and reduced the concentrations of citric acid in root exudates by 71.4% and in roots by 83.5%. However, organic acids did not influence R. solanacearum growth. Results also demonstrated that salicylic acid（SA） content in roots was significantly increased by silicon addition for H7996 and exogenous SA application could reduce bacterial wilt disease index. Collectively, these results suggest that Si-modulated phenolic compound metabolism in roots or root exudates, especially citric acid and SA, may be a potential mechanism in the amelioration of bacterial wilt disease by Si.展开更多
The tobacco Ralstonia Solanacearum were both cultured on nutrient agar plates and inoculated in seedling stage of tobacco, then treated with K1 and K2, two anti-bacterial agents, at a serial con-centrations to study t...The tobacco Ralstonia Solanacearum were both cultured on nutrient agar plates and inoculated in seedling stage of tobacco, then treated with K1 and K2, two anti-bacterial agents, at a serial con-centrations to study their inhibitory efficiency. The result indicated that K1 can inhibit R. Solanacearum growth entirely, at the concentration range from 1/50 to 1/5000. K2 can reach the same result at the concentration range from 1/50 to 1/50000. Compared with the control plates, K1, at the concentration 1/50000, had no significant differences, and the average number of colony per plate was 112-115. The immature tobacco shown wilt as soon as inoculated with R. Solanacearum, and recovered gradually after using K1, K2. The densities of microbial suspension, handled by K1, K2 within 10 hs, were both significantly lower than the controlled ones. The optical microscopy also shown that handled microbial body differed from the controlled, whose body was regular short, rod shape as opposed to the handled ones with irregular rod shape and damaged body. All the results indicated that K1 and K2 both had inhibitory effects on tobacco R. Solanacearum, and K2 was more efficient than K1.展开更多
[Objective]The paper was to optimize the tobacco planting area in Fuzhou City and to prevent the outbreak of tobacco bacterial wilt in large area.[Method]At the end of 2017,soil samples were collected from plots plann...[Objective]The paper was to optimize the tobacco planting area in Fuzhou City and to prevent the outbreak of tobacco bacterial wilt in large area.[Method]At the end of 2017,soil samples were collected from plots planned to be planted with tobacco in the following year in Yihuang,Guangchang,Lichuan and Le’an counties.[Result]Among 352 plots,116 plots were infected by Ralstonia solanacearum,while 236 plots were free of the pathogen,and the infected plots accounted for 32.95% of total plots.Among them,75 plots exceeded the order of magnitudes of 103,accounting for 21.31% of total plots and 64.66% of infected plots.It is suggested that the plots with an order of magnitude above 103 should be pretreated with quicklime or purple soil,or conducted crop rotation,or seeds must be directly abandoned;the dosage of biocontrol agents should be increased in planting.The plots with an order of magnitude below 103 should be pretreated with quicklime or purple soil,and the dosage of biocontrol agents should be increased in planting.[Conclusion]The results provide reliable theoretical basis and data support for soil improvement and bacterial wilt control.展开更多
This study is to investigate the role of lipid transfer protein （LTP1） gene of potato （Solanum tuberosum） in bacterial wilt （Ralstonia solanacearum） resistance. A novel cDNA clone encoding nsLTP was isolated fro...This study is to investigate the role of lipid transfer protein （LTP1） gene of potato （Solanum tuberosum） in bacterial wilt （Ralstonia solanacearum） resistance. A novel cDNA clone encoding nsLTP was isolated from cultivated potato （Solanum tuberosum） infected with R. solanacearum by 5＇-rapid amplification of cDNA ends （RACE）. The temporal and spatial expression of StLTPbl was studied during the early stages of potato-R, solanacearum interaction by reverse transcriptase PCR （RT-PCR） and Northern blotting. The sequence analysis of the cloned cDNA, named StLTPbl, showed 691 bp which encoded a type 1 nsLTP of 91 amino acids. Construction of a phylogenic tree showed that StLTPbl is well conserved in the coding region with high identity at the amino acid level with other Solanaceae nsLTPs. The temporal and spatial expression of StLTPbl was studied during the early stages of potato-R, solanacearum interaction. StLTPbl transcription is induced faster and transcripts accumulate to higher concentrations in resistant compared with susceptible genotypes by the pathogen. Dominant differences in the pathogen-induced gene expression pattern between the upper and lower leaves and stems were observed within the same genotypes. In situ hybridization results showed that the StLTPbl mRNA was localized in phloem cells of vascular tissues in potato leaf and stem tissues after pathogen infection. Salicylic acid, methyl jasmonate and abscisic acid could induce StLTPbl gene expression without significant difference between the upper and lower tissues. These abiotic elicitors could produce a long-lastingeffect on the StLTPbl during early stages of potato-R, solanacearum interaction. Differential expression of StLTPbl gene between resistance and susceptible potato genotypes in response to R. solanacearum suggests that this gene plays a key role in plant defense mechanisms.展开更多
基金This work was supported by the National Natural Science Foundation of China(32072399 and 32272641)the Fundamental Research Funds for the Central Universities(GK202201017 and GK202207024)the Program of Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests,China(MIMCP-202203).
文摘Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops,leading to huge losses in crop production every year.Understanding of plant-R.solanacearum interactions will aid to develop efficient strategies to control the disease.As a soilborne pathogen,R.solanacearum naturally infects plants via roots.A huge limitation in studying plant-R.solanacearum interactions is the large variation of R.solanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.Here,we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.This method is easy to use,takes about only 10 days from seed germination to the completion of inoculation assay,and requires less inoculum of bacteria as well as growth chamber space.We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns,resistance of defense-related plant mutants,and virulence of R.solanacearum mutants.Furthermore,we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.
文摘BACKGROUND Ralstonia is a Gram-negative non-fermentative bacterium widespread in nature,and includes four species,Ralstonia pickettii,Ralstonia solanacearum,Ralstonia mannitolilytica,and Ralstonia insidiosa,which were proposed in 2003.Ralstonia is mainly found in the external water environment,including municipal and medical water purification systems.This bacterium has low toxicity and is a conditional pathogen.It has been reported in recent years that infections due to Ralstonia are increasing.Previous studies have shown that most cases of infection are caused by Ralstonia pickettii,a few by Ralstonia mannitolilytica,and infections caused by Ralstonia insidiosa are rare.CASE SUMMARY A 2-year-old Chinese child suffered from intermittent fever and cough for 20 d and was admitted to hospital with bronchial pneumonia.Bronchoscopy and alveolar lavage fluid culture confirmed Ralstonia insidiosa pneumonia.The infection was well controlled after treatment with meropenem and azithromycin.CONCLUSION Ralstonia infections are increasing,and we report a rare case of Ralstonia insidiosa infection in a child.Clinicians should be vigilant about Ralstonia infections.
基金financially supported by grants from the National Natural Science Foundation of China (31370456)the Doctoral Foundation of the Ministry of Education of China (20124404110007)+1 种基金the Natural Science Foundation of Guangdong Province of China (S2012010010331 and 2017A030313177)the Project of International, as well as Hong Kong, Macao & Taiwan Science and Technology Cooperation Innovation Platform in Universities in Guangdong Province, China (2014KGJHZ004)
文摘Silicon(Si) can increase plant resistance against bacterial wilt caused by Ralstonia solanacearum and enhance plant immune response. However, whether Si alleviates soil-borne disease stress through altering soil microbial community component and diversity is not clear. In this study, effects of Si application under R. solanacearum inoculation with or without plant on soil bacterial and fungal communities were investigated through high-throughput pyrosequencing technique. The results showed that Si addition significantly reduced bacterial wilt incidence. However, Si did not reduce the amount of R. solanacearum in rhizosphere soil. Principal components analysis showed that soil microbial community composition was strongly influenced by Si addition. Total 63.7% bacterial operational taxonomic units(OTUs) and 43.8% fungal OTUs were regulated by Si addition regardless of the presence of tomato plants, indicating the independent effects of Si on soil microbial community. Si-added soil harbored a lower abundance of Fusarium, Pseudomonas, and Faecalibacterium. Our finding further demonstrated that exogenous Si could significantly influence soil microbial community component, and this may provide additional insight into the mechanism of Si-enhanced plant resistance against soil-borne pathogens.
基金financially supported by grants from the National Natural Science Foundation of China (31370456)the Natural Science Foundation of Guangdong Province, China (2017A030313177)
文摘Bacterial wilt, caused by Ralstonia solanacearum（Rs） is a serious soil-borne disease and silicon can enhance tomato resistance against this disease. However, few studies have focused on the mechanisms of Si-mediated pathogen resistance from the rhizosphere perspective. In this study, two tomato genotypes, HYT（susceptible） and H7996（resistant）, were used to investigate the effects of silicon application on disease inhibition, root growth, and organic acid content in both roots and root exudates under R. solanacearum infection. The results showed that Si application significantly suppressed bacterial wilt in HYT, but had no effect in H7996. Silicon concentrations in roots, stems and leaves of tomato were significantly increased by Si treatment under R. solanacearum inoculation. In HYT, Si application increased root dry weight by 22.8-51.6% and leaf photosynthesis by 30.6-208.0%, and reduced the concentrations of citric acid in root exudates by 71.4% and in roots by 83.5%. However, organic acids did not influence R. solanacearum growth. Results also demonstrated that salicylic acid（SA） content in roots was significantly increased by silicon addition for H7996 and exogenous SA application could reduce bacterial wilt disease index. Collectively, these results suggest that Si-modulated phenolic compound metabolism in roots or root exudates, especially citric acid and SA, may be a potential mechanism in the amelioration of bacterial wilt disease by Si.
文摘The tobacco Ralstonia Solanacearum were both cultured on nutrient agar plates and inoculated in seedling stage of tobacco, then treated with K1 and K2, two anti-bacterial agents, at a serial con-centrations to study their inhibitory efficiency. The result indicated that K1 can inhibit R. Solanacearum growth entirely, at the concentration range from 1/50 to 1/5000. K2 can reach the same result at the concentration range from 1/50 to 1/50000. Compared with the control plates, K1, at the concentration 1/50000, had no significant differences, and the average number of colony per plate was 112-115. The immature tobacco shown wilt as soon as inoculated with R. Solanacearum, and recovered gradually after using K1, K2. The densities of microbial suspension, handled by K1, K2 within 10 hs, were both significantly lower than the controlled ones. The optical microscopy also shown that handled microbial body differed from the controlled, whose body was regular short, rod shape as opposed to the handled ones with irregular rod shape and damaged body. All the results indicated that K1 and K2 both had inhibitory effects on tobacco R. Solanacearum, and K2 was more efficient than K1.
文摘[Objective]The paper was to optimize the tobacco planting area in Fuzhou City and to prevent the outbreak of tobacco bacterial wilt in large area.[Method]At the end of 2017,soil samples were collected from plots planned to be planted with tobacco in the following year in Yihuang,Guangchang,Lichuan and Le’an counties.[Result]Among 352 plots,116 plots were infected by Ralstonia solanacearum,while 236 plots were free of the pathogen,and the infected plots accounted for 32.95% of total plots.Among them,75 plots exceeded the order of magnitudes of 103,accounting for 21.31% of total plots and 64.66% of infected plots.It is suggested that the plots with an order of magnitude above 103 should be pretreated with quicklime or purple soil,or conducted crop rotation,or seeds must be directly abandoned;the dosage of biocontrol agents should be increased in planting.The plots with an order of magnitude below 103 should be pretreated with quicklime or purple soil,and the dosage of biocontrol agents should be increased in planting.[Conclusion]The results provide reliable theoretical basis and data support for soil improvement and bacterial wilt control.
基金grateful to Ren Caihong(College of Life Science,Shanxi Normal University of China)for technical assistance.This work was supported by National 863 Program(2003AA207130)Natural Science Foundation of Shanxi Province of China(20051042).
文摘This study is to investigate the role of lipid transfer protein （LTP1） gene of potato （Solanum tuberosum） in bacterial wilt （Ralstonia solanacearum） resistance. A novel cDNA clone encoding nsLTP was isolated from cultivated potato （Solanum tuberosum） infected with R. solanacearum by 5＇-rapid amplification of cDNA ends （RACE）. The temporal and spatial expression of StLTPbl was studied during the early stages of potato-R, solanacearum interaction by reverse transcriptase PCR （RT-PCR） and Northern blotting. The sequence analysis of the cloned cDNA, named StLTPbl, showed 691 bp which encoded a type 1 nsLTP of 91 amino acids. Construction of a phylogenic tree showed that StLTPbl is well conserved in the coding region with high identity at the amino acid level with other Solanaceae nsLTPs. The temporal and spatial expression of StLTPbl was studied during the early stages of potato-R, solanacearum interaction. StLTPbl transcription is induced faster and transcripts accumulate to higher concentrations in resistant compared with susceptible genotypes by the pathogen. Dominant differences in the pathogen-induced gene expression pattern between the upper and lower leaves and stems were observed within the same genotypes. In situ hybridization results showed that the StLTPbl mRNA was localized in phloem cells of vascular tissues in potato leaf and stem tissues after pathogen infection. Salicylic acid, methyl jasmonate and abscisic acid could induce StLTPbl gene expression without significant difference between the upper and lower tissues. These abiotic elicitors could produce a long-lastingeffect on the StLTPbl during early stages of potato-R, solanacearum interaction. Differential expression of StLTPbl gene between resistance and susceptible potato genotypes in response to R. solanacearum suggests that this gene plays a key role in plant defense mechanisms.
