This study was done to determine the causal organism of the pear blossom and bud blast in China. It was identified by a bacteriological test, electro-microscopic observation, Koch＇s postulate test, Biolog, fatty acid...This study was done to determine the causal organism of the pear blossom and bud blast in China. It was identified by a bacteriological test, electro-microscopic observation, Koch＇s postulate test, Biolog, fatty acid methyl esters （FAMEs）, and a polymerase chain reaction （PCR） test, and compared with the standard reference strains. Six representative strains out of 20 pathogenic bacterial isolates from 16 diseased samples showed characteristics similar to three standard strains of Pseudomonas syringae pv. syringae from Belgium. They were identified as P. syringae pv. syringae with a Biolog similarity of 0.57-0.86 and FAMEs similarity of 0.58-0.81. The bacterium was reisolated from the symptomatic plants and blossoms. Identification as P. syringae pv. syringae was confirmed by using PCR primers and sequence tests, and compared with the above-mentioned results. The data supported the fact that the pear blossom and bud blast in China could be caused by P. syringae pv. syringae.展开更多
[ Objective ] The paper was to confirrm the effect of hrpZpsg12 gene on the pathogenicity of Pseudomonas syringae pv. glycinea. [ Method ] hrpZpsg12 gene was cloned from P. syringae using PCR method. The knockout plas...[ Objective ] The paper was to confirrm the effect of hrpZpsg12 gene on the pathogenicity of Pseudomonas syringae pv. glycinea. [ Method ] hrpZpsg12 gene was cloned from P. syringae using PCR method. The knockout plasmid pKNOCK-Cm with suicide characteristics and cosmid pUFR034 with complementation func- tion were used to construct the mutation vector pKNOCK477-7 and complementary vector pUFR1026-68 of hrpZpsg12 gene, the mutant 477-1 and the functional com- plementation unit 1026-5 of the gene was also screened out. Three strains including wild-type Psg12, mutant 477-1 and complementary unit 1026-5 were simultane- ously inoculated into soybean leaves and tobacco leaves, then pathogenicity determination and hypersensitive reaction analysis were carried out. [ Result] All the inoculated leaves of soybean and tobacco produced reaction lesion. However, the sizes of reaction lesion were different. The lesion in the leaves inoculated with Psgl2 was relatively large, while the lesion in the leaves inoculated with 477-1 was relatively small; the lesion of complementary unit 1026-5 was similar to wild- type Psgl2. Analysis of reproduction quantity of bacteria in lesions showed that the reproduction quantity of wild-type Psg12 was the highest, while that of mutant 477-1 was the lowest. The reproduction quantity of complementary unit 1026-5 was similar to that of wild-type Psg12. [ Conclusion] hrpZpsg12 gene could enhance the pathogenicity of P. syrimgae on Soybean and produce hypersensitive response in tobacco.展开更多
Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two ge...Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.展开更多
Mulberry bacterial blight is caused by Pseudomonas syringae pv. mori. Coronatine （COR）, a phytotoxin and phytohormone produced by several strains of Pseudomonas syringae, is suggested to have an important role in pa...Mulberry bacterial blight is caused by Pseudomonas syringae pv. mori. Coronatine （COR）, a phytotoxin and phytohormone produced by several strains of Pseudomonas syringae, is suggested to have an important role in pathogen-plant interaction. The aim of our study was to examine the influence of COR on mul- berry in the process of pathogen infection. Results showed that COR could suppress stomatal closure induced by pathogen-associated molecular patterns （PAMPS）, assist pathogenic bacteria into the leaves, and promote bacterial proliferation in the tissues. High-concentration （1 μmol/L） exogenous COR and COR-producing bacterial pathogen induced chlorosis symptom and decrease of chlorophyll content, contrary to the effects of low-concentration （0.001 μmol/L） exogenous COR and non-COR-preducing bacterial pathogen. Treatments with COR and DC3000 enhanced the production of reactive oxygen species （ ROS）, namely, hydrogen peroxide （H2O2 ） and superexide anion （O2-）, but there were two H2O2 peaks at 1 -3 hpi and 8 -24 hpi in the DC3000-treated leaves while only one peak at 1 -3 h was observed 1 -3 h in the COR-treated ones. H202 could kill the pathogenic bacteria, on the other hand, it also acted as an upstream signaling molecule to promote nitric oxide （NO） production to further participate in the signaling pathway. Enzymatic antioxidant systems （superoxide dismutase, peroxidase and catalase） and defensive enzyme systems （lipoxygenase, polyphenol oxidase and phenylalnine ammonialyase） were activated by COR. Therefore, COR could cooperate on the inva- sion and proliferation of COR-producing bacterial pathogens, and induce the chloresis symptom in mulberry. At the same time, exogenously applied COR also could enhance the resistance to P. syringae pv. mori by production of signal molecules to activate signaling pathway and promoting defense-related metabolism.展开更多
Soybean bacterial spot disease caused by Pseudomonas syringae pv.Glycinea which is a bacterial disease seriously affects soybean yield.Ten soybean germplasms and recombinant inbred lines(RILs)population were used to i...Soybean bacterial spot disease caused by Pseudomonas syringae pv.Glycinea which is a bacterial disease seriously affects soybean yield.Ten soybean germplasms and recombinant inbred lines(RILs)population were used to identify the resistant trait after inoculated with P.sg(P.sgneau001)in this study.High-density genetic mapping was obtained by specific length amplified fragment sequencing(SLAF-seq)of 149 RILs population which was derived from the crossing between Charleston and Dongnong594.The results indicated that 10 germplasm resources had four resistant germplasms included highly resistant cultivar Charleston,four susceptible varieties included Dongnong594 and two moderately resistant cultivars.Five quantitative trait locus(QTLs)were detected in RILs population by the composite interval mapping(CIM)method,and located on Linkage Group(LG)D1b(chromosome two),LG C2(chromosome six)and LG H(chromosome 12),respectively.LOD scores ranged from 2.68 to 4.95 and the phenotypic variation percentage was from 6%to 11%.Six candidate genes were detected,according to the result of gene annotation information.Four of them had relationship with protein kinase activity,protein phosphorylation and leucine rich repeat(LRR)transmembrane protein,which had high expression after inoculated with P.sg by qRT-PCR.展开更多
Some Pseudomonas syringae pathovars secrete tabtoxin, a monocyclic β-lactam antibiotic, responsible for chlorosis, the principal halo blight symptom in susceptible plants as oats, rye, barley, wheat and sorghum, amon...Some Pseudomonas syringae pathovars secrete tabtoxin, a monocyclic β-lactam antibiotic, responsible for chlorosis, the principal halo blight symptom in susceptible plants as oats, rye, barley, wheat and sorghum, among other. Here, we demonstrated that the production of tabtoxin in a P. syringae strain increased at least 150%, when choline, betaine or dimethylglycine were used as nitrogen source, or when choline was added as osmoprotectant in hyperosmolar culture media. Besides, we investigated the induction of phosphorylcholine phosphatase (PchP) activity when choline or its metabolites were used as nitrogen sources. PchP is an enzyme involved in Pseudomonas aeruginosa pathogenesis through its contribution to the breakdown of choline-containing compounds of the host cells. Considering these results and that the success of a pathogenic microorganism depends on its ability to survive and proliferate in its target tissue, we propose that choline is one of the plant signals that contribute to establishment of the infection by tabtoxin-producing strains of P. syringae.展开更多
基金the National High Technology Research and Development Program of China (2006AA10A211)National Natural Science Foundation of China (30671397)Hangzhou Agricultural Development Foundation,China (2007-2008)
文摘This study was done to determine the causal organism of the pear blossom and bud blast in China. It was identified by a bacteriological test, electro-microscopic observation, Koch＇s postulate test, Biolog, fatty acid methyl esters （FAMEs）, and a polymerase chain reaction （PCR） test, and compared with the standard reference strains. Six representative strains out of 20 pathogenic bacterial isolates from 16 diseased samples showed characteristics similar to three standard strains of Pseudomonas syringae pv. syringae from Belgium. They were identified as P. syringae pv. syringae with a Biolog similarity of 0.57-0.86 and FAMEs similarity of 0.58-0.81. The bacterium was reisolated from the symptomatic plants and blossoms. Identification as P. syringae pv. syringae was confirmed by using PCR primers and sequence tests, and compared with the above-mentioned results. The data supported the fact that the pear blossom and bud blast in China could be caused by P. syringae pv. syringae.
基金Supported by Scientific Research Foundation Project of Jilin Agricultural University" hrpZ Psg12 Protein Function of Pseudomonas syringae pv.glycinea" (384)Major Project of Cultivation of Genetically Modified Biological New Varieties of "Eleventh Five-Year Plan" of Ministry of Agriculture"Cultivation of New Transgenic Varieties of Soybean with Diseases and Pests Resistance"(2008ZX08004-004)~~
文摘[ Objective ] The paper was to confirrm the effect of hrpZpsg12 gene on the pathogenicity of Pseudomonas syringae pv. glycinea. [ Method ] hrpZpsg12 gene was cloned from P. syringae using PCR method. The knockout plasmid pKNOCK-Cm with suicide characteristics and cosmid pUFR034 with complementation func- tion were used to construct the mutation vector pKNOCK477-7 and complementary vector pUFR1026-68 of hrpZpsg12 gene, the mutant 477-1 and the functional com- plementation unit 1026-5 of the gene was also screened out. Three strains including wild-type Psg12, mutant 477-1 and complementary unit 1026-5 were simultane- ously inoculated into soybean leaves and tobacco leaves, then pathogenicity determination and hypersensitive reaction analysis were carried out. [ Result] All the inoculated leaves of soybean and tobacco produced reaction lesion. However, the sizes of reaction lesion were different. The lesion in the leaves inoculated with Psgl2 was relatively large, while the lesion in the leaves inoculated with 477-1 was relatively small; the lesion of complementary unit 1026-5 was similar to wild- type Psgl2. Analysis of reproduction quantity of bacteria in lesions showed that the reproduction quantity of wild-type Psg12 was the highest, while that of mutant 477-1 was the lowest. The reproduction quantity of complementary unit 1026-5 was similar to that of wild-type Psg12. [ Conclusion] hrpZpsg12 gene could enhance the pathogenicity of P. syrimgae on Soybean and produce hypersensitive response in tobacco.
基金supported by the grants from the Genetically Modified Organisms Breeding Major Projects, China (2014ZX0800905B)the Fundamental Research Funds for the Central Universities, Chinathe Program for New Century 151 Talents of Zhejiang Province, China
文摘Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.
基金Supported by the Science and Technology Support Program of the Jiangsu Province(BE2012365)the Modern Agro-industry Technology Research System of China(CARS-22)
文摘Mulberry bacterial blight is caused by Pseudomonas syringae pv. mori. Coronatine （COR）, a phytotoxin and phytohormone produced by several strains of Pseudomonas syringae, is suggested to have an important role in pathogen-plant interaction. The aim of our study was to examine the influence of COR on mul- berry in the process of pathogen infection. Results showed that COR could suppress stomatal closure induced by pathogen-associated molecular patterns （PAMPS）, assist pathogenic bacteria into the leaves, and promote bacterial proliferation in the tissues. High-concentration （1 μmol/L） exogenous COR and COR-producing bacterial pathogen induced chlorosis symptom and decrease of chlorophyll content, contrary to the effects of low-concentration （0.001 μmol/L） exogenous COR and non-COR-preducing bacterial pathogen. Treatments with COR and DC3000 enhanced the production of reactive oxygen species （ ROS）, namely, hydrogen peroxide （H2O2 ） and superexide anion （O2-）, but there were two H2O2 peaks at 1 -3 hpi and 8 -24 hpi in the DC3000-treated leaves while only one peak at 1 -3 h was observed 1 -3 h in the COR-treated ones. H202 could kill the pathogenic bacteria, on the other hand, it also acted as an upstream signaling molecule to promote nitric oxide （NO） production to further participate in the signaling pathway. Enzymatic antioxidant systems （superoxide dismutase, peroxidase and catalase） and defensive enzyme systems （lipoxygenase, polyphenol oxidase and phenylalnine ammonialyase） were activated by COR. Therefore, COR could cooperate on the inva- sion and proliferation of COR-producing bacterial pathogens, and induce the chloresis symptom in mulberry. At the same time, exogenously applied COR also could enhance the resistance to P. syringae pv. mori by production of signal molecules to activate signaling pathway and promoting defense-related metabolism.
基金Supported by the National Key R&D Program of China(2016YFD0100201)Science Foundation for Distinguished Young Scholars of Heilongjiang Province(JC2016004)Harbin Science Technology Project(2015RQXXJ018)。
文摘Soybean bacterial spot disease caused by Pseudomonas syringae pv.Glycinea which is a bacterial disease seriously affects soybean yield.Ten soybean germplasms and recombinant inbred lines(RILs)population were used to identify the resistant trait after inoculated with P.sg(P.sgneau001)in this study.High-density genetic mapping was obtained by specific length amplified fragment sequencing(SLAF-seq)of 149 RILs population which was derived from the crossing between Charleston and Dongnong594.The results indicated that 10 germplasm resources had four resistant germplasms included highly resistant cultivar Charleston,four susceptible varieties included Dongnong594 and two moderately resistant cultivars.Five quantitative trait locus(QTLs)were detected in RILs population by the composite interval mapping(CIM)method,and located on Linkage Group(LG)D1b(chromosome two),LG C2(chromosome six)and LG H(chromosome 12),respectively.LOD scores ranged from 2.68 to 4.95 and the phenotypic variation percentage was from 6%to 11%.Six candidate genes were detected,according to the result of gene annotation information.Four of them had relationship with protein kinase activity,protein phosphorylation and leucine rich repeat(LRR)transmembrane protein,which had high expression after inoculated with P.sg by qRT-PCR.
文摘Some Pseudomonas syringae pathovars secrete tabtoxin, a monocyclic β-lactam antibiotic, responsible for chlorosis, the principal halo blight symptom in susceptible plants as oats, rye, barley, wheat and sorghum, among other. Here, we demonstrated that the production of tabtoxin in a P. syringae strain increased at least 150%, when choline, betaine or dimethylglycine were used as nitrogen source, or when choline was added as osmoprotectant in hyperosmolar culture media. Besides, we investigated the induction of phosphorylcholine phosphatase (PchP) activity when choline or its metabolites were used as nitrogen sources. PchP is an enzyme involved in Pseudomonas aeruginosa pathogenesis through its contribution to the breakdown of choline-containing compounds of the host cells. Considering these results and that the success of a pathogenic microorganism depends on its ability to survive and proliferate in its target tissue, we propose that choline is one of the plant signals that contribute to establishment of the infection by tabtoxin-producing strains of P. syringae.
