Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effect...Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effects on R. solanacearum, we first assessed the impact of limonene on the physiological indicators of the pathogen and subsequently analyzed its transcriptome and metabolome. Our findings indicate that limonene has a potent inhibitory effect on R. solanacearum, and it also suppresses the formation of the bacterial community biofilm. Limonene primarily regulates the terpene biosynthesis pathway in R. solanacearum, thereby potentially affecting signal transduction in the pathogen and disrupting its normal growth and development. These results significantly enhance our understanding of limonene’s response to the induction of bacterial wilt and provide a reference for further prevention and control of R. solanacearum.展开更多
[ Objective ] The paper was to isolate and identify Ralstonia solanacearum from white burley, and determine its susceptibility to 6 fungicides. [ Mcth- od] Using the combination method of semiselective medium （PCCG）...[ Objective ] The paper was to isolate and identify Ralstonia solanacearum from white burley, and determine its susceptibility to 6 fungicides. [ Mcth- od] Using the combination method of semiselective medium （PCCG） and apolymerase chain reaction （PCR） technique, R. solanacearum in stalk of white burley from Dazhou City in Sichnan Province was isolated, and its biochemical type was identified. Through susceptibility test, the susceptibility of R. solanacearum to bismerthiazol, ethylicin, streptomycin, lime sulfur, 47% polylysine, 99% kojic acid was studied in laboratory. [Result] A total of 23 strains OfR. solanacearum were isolated, all belonging to biochemical type Ill. R. solanacearum obtained in the test were more susceptible to ethylicin, streptomycin and bismerthiazol, and ethylicin had good control effect against R. solanacearum with ECso of 0.086 ml/L. [ Conclusion ] The study provide theoretical basis for control of R. solanaceanon in white burley.展开更多
[ Objective] The paper was to screen Bacillus with strong antagonistic effect. [ Method] The diseased ginger and the surrounding soils were collected from Laiwu of Shandong Province, and the high-virulence strains of ...[ Objective] The paper was to screen Bacillus with strong antagonistic effect. [ Method] The diseased ginger and the surrounding soils were collected from Laiwu of Shandong Province, and the high-virulence strains of the pathogen of ginger blast （Ralstonia solanacearum） were isolated, Bacillus was used to carry out antagonistic test. [Result] Three strains LW-4, LW-7 and LW-32 had strong antagonistic effect against R. solanacearum, the area of their inhibition zone was larger than other strains. [ Conclusion] The study provided theoretical basis for the control of ginger blast.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
The psyllid Bactericera cockerelli was first reported in New Zealand in 2006 and spread quickly throughout all potato growing regions.In 2009,B.cockerelli was associated with the plant pathogenic bacterium Candidatus ...The psyllid Bactericera cockerelli was first reported in New Zealand in 2006 and spread quickly throughout all potato growing regions.In 2009,B.cockerelli was associated with the plant pathogenic bacterium Candidatus Liberibacter solanacearum,the putative causal agent of zebra chip disease in potato.Both the psyllid and the bacterium have non-crop host plants which can serve as reservoirs when the crop is not available.Growers apply different management strategies that fit integrated pest management programmes to manage B.cockerelli and subsequently lower incidence of zebra chip disease in potato crops.Despite best management efforts,complete control of B.cockerelli and zero incidence of zebra chip disease are not achievable at the current time.展开更多
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
This unique study evaluates the effects of Ralstonia solanacearum (Rs) induced biotic stress in two cultivars, Zingiber officinale (ginger) and Lycopersicon esculentum (tomato). They were grown in pots and hydroponic ...This unique study evaluates the effects of Ralstonia solanacearum (Rs) induced biotic stress in two cultivars, Zingiber officinale (ginger) and Lycopersicon esculentum (tomato). They were grown in pots and hydroponic systems with controls;to induce biotic stress, about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high in both plants;while they showed decreased starch and protein contents;phenolics showed a swing of decrease or increase between pot and hydroponic systems;and all plants in general showed higher (3-6 fold) proline content upon induction of biotic stress. Regarding oxidative stress isozymes (OSE), superoxide dismutase (EC 1.15.1.1) isozymes were normally 3, but treated hydroponics had 4 with comparable relative mobility values;peroxidase (EC 1.11.1.7) isozymes were generally 2, except for treated hydroponic tomato. Briefly, Rs induced biotic stress caused wilt symptoms in ginger, but did not affect tomato though its biochemical and OSE patterns especially in those grown as hydroponics were elicited to significantly higher levels.展开更多
文摘Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effects on R. solanacearum, we first assessed the impact of limonene on the physiological indicators of the pathogen and subsequently analyzed its transcriptome and metabolome. Our findings indicate that limonene has a potent inhibitory effect on R. solanacearum, and it also suppresses the formation of the bacterial community biofilm. Limonene primarily regulates the terpene biosynthesis pathway in R. solanacearum, thereby potentially affecting signal transduction in the pathogen and disrupting its normal growth and development. These results significantly enhance our understanding of limonene’s response to the induction of bacterial wilt and provide a reference for further prevention and control of R. solanacearum.
基金Supported by Sichuan Tobacco Monopoly Bureau Project ( 200901009)~~
文摘[ Objective ] The paper was to isolate and identify Ralstonia solanacearum from white burley, and determine its susceptibility to 6 fungicides. [ Mcth- od] Using the combination method of semiselective medium （PCCG） and apolymerase chain reaction （PCR） technique, R. solanacearum in stalk of white burley from Dazhou City in Sichnan Province was isolated, and its biochemical type was identified. Through susceptibility test, the susceptibility of R. solanacearum to bismerthiazol, ethylicin, streptomycin, lime sulfur, 47% polylysine, 99% kojic acid was studied in laboratory. [Result] A total of 23 strains OfR. solanacearum were isolated, all belonging to biochemical type Ill. R. solanacearum obtained in the test were more susceptible to ethylicin, streptomycin and bismerthiazol, and ethylicin had good control effect against R. solanacearum with ECso of 0.086 ml/L. [ Conclusion ] The study provide theoretical basis for control of R. solanaceanon in white burley.
文摘[ Objective] The paper was to screen Bacillus with strong antagonistic effect. [ Method] The diseased ginger and the surrounding soils were collected from Laiwu of Shandong Province, and the high-virulence strains of the pathogen of ginger blast （Ralstonia solanacearum） were isolated, Bacillus was used to carry out antagonistic test. [Result] Three strains LW-4, LW-7 and LW-32 had strong antagonistic effect against R. solanacearum, the area of their inhibition zone was larger than other strains. [ Conclusion] The study provided theoretical basis for the control of ginger blast.
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.
基金supported by the New Zealand Institute for Plant and Food Research Limited Internal Core fundingthe Plant Biosecurity Cooperative Research Centre (Australia) (CRC2079)the Sustainable Farming Fund (New Zealand, 09/143, 12/058, and 404861)Potatoes New Zealand Inc.
文摘The psyllid Bactericera cockerelli was first reported in New Zealand in 2006 and spread quickly throughout all potato growing regions.In 2009,B.cockerelli was associated with the plant pathogenic bacterium Candidatus Liberibacter solanacearum,the putative causal agent of zebra chip disease in potato.Both the psyllid and the bacterium have non-crop host plants which can serve as reservoirs when the crop is not available.Growers apply different management strategies that fit integrated pest management programmes to manage B.cockerelli and subsequently lower incidence of zebra chip disease in potato crops.Despite best management efforts,complete control of B.cockerelli and zero incidence of zebra chip disease are not achievable at the current time.
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This unique study evaluates the effects of Ralstonia solanacearum (Rs) induced biotic stress in two cultivars, Zingiber officinale (ginger) and Lycopersicon esculentum (tomato). They were grown in pots and hydroponic systems with controls;to induce biotic stress, about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high in both plants;while they showed decreased starch and protein contents;phenolics showed a swing of decrease or increase between pot and hydroponic systems;and all plants in general showed higher (3-6 fold) proline content upon induction of biotic stress. Regarding oxidative stress isozymes (OSE), superoxide dismutase (EC 1.15.1.1) isozymes were normally 3, but treated hydroponics had 4 with comparable relative mobility values;peroxidase (EC 1.11.1.7) isozymes were generally 2, except for treated hydroponic tomato. Briefly, Rs induced biotic stress caused wilt symptoms in ginger, but did not affect tomato though its biochemical and OSE patterns especially in those grown as hydroponics were elicited to significantly higher levels.
