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1.
Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, one of the most widespread and destructive bacterial diseases in rice. In order to understand
the gene of zinc uptake regulator (zur) involved in virulence of the pathogen in rice, we generated a mutant OSZRM by homologous suicide plasmid integration. The
mutant failed to grow in NYGB medium supplemented with Zn2+ or Fe3+ at a concentration of 500 μM or 6 mM, whereas the wild-type strain grew well at the same conditions. The zur mutant was hypersensitive to hydrogen peroxide and exhibited reduction catalase activity and the production of extracellular
polysaccharide (EPS). Interestingly, the mutant showed a reduction in virulence on rice but still kept triggering hypersensitive
response (HR) in tobacco. When the mutant was complemented with the zur gene, the response was recovered to wild-type. These results suggested that zur gene is a functional member of the Zur regulator family that controls zinc and iron homeostasis, oxidative stress, and EPS
production, which is necessary for virulence in X. oryzae pv. oryzae.
Wanfeng Yang and Yan Liu contributed equally to this work 相似文献
2.
Genome sequence analysis of Xanthomonas
oryzae pv. oryzae has revealed a cluster of 12 ORFs that are closely related to the gum gene cluster of Xanthomonas campestris pv. campestris. The gum gene cluster of X. oryzae encodes proteins involved in xanthan production; however, there is little experimental evidence supporting this. In this
study, biochemical analyses of xanthan produced by a defined set of X. oryzae
gum mutant strains allowed us to preliminarily assign functions to most of the gum gene products: biosynthesis of the pentasaccharide repeating unit for GumD, GumM, GumH, GumK, and GumI, xanthan polymerization
and transport for GumB, GumC, GumE, and GumJ, and modification of the pentasaccharide repeating unit for GumF, GumG, and GumL.
In addition, we found that the exopolysaccharides are essential but not specific for the virulence of X. oryzae.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Sang-Yoon Kim and Jeong-Gu Kim contributed equally to this work. 相似文献
3.
Xanthomonas oryzae pv. oryzae is the pathogen that causes bacterial leaf blight in rice. Bacterial leaf blight is the main cause for severe rice underproduction
in many countries. However, with conventional methods it is difficult to quickly and reliably distinguish this pathogen from
other closely related pathogenic bacteria, especially X. oryzae pv. oryzicola, the causal organism of bacterial leaf streak in rice. We have developed a novel and highly sensitive real-time method for
the identification of this specific bacteria based on a TaqMan probe. This probe is designed to recognize the sequence of
a putative siderophore receptor gene cds specific to X. oryzae pv. oryzae, and can be identified from either a bacterial culture or naturally infected rice seeds and leaves in only 2 h. The sensitivity
of the method is 100 times higher than that of the current polymerase chain reaction (PCR) gel electrophoresis method for
diagnosis. 相似文献
4.
5.
Background
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight disease. Xoo produces a range of virulence factors, including EPS, extracellular enzyme, iron-chelating siderophores, and type III-secretion dependent effectors, which are collectively essential for virulence. Genetic and genomics evidence suggest that Xoo might use the diffusible signal factor (DSF) type quorum sensing (QS) system to regulate the virulence factor production. However, little is known about the chemical structure of the DSF-like signal(s) produced by Xoo and the factors influencing the signal production. 相似文献6.
Lim SH So BH Wang JC Song ES Park YJ Lee BM Kang HW 《Journal of microbiology (Seoul, Korea)》2008,46(2):214-220
Bacterial blight (BB) of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is the most devastating bacterial disease in rice. A virulence-attenuated mutant strain HNU89K9 of X. oryzae pv. oryzae (KACC10331), with a transposon insertion in the pilQ gene was used for this study. The pilQ was involved in the gene cluster pilMNOPQ of the Xoo genome. Growth rate of the pilQ mutant was similar to that of wild-type. At level of amino acids, PilQ of Xoo showed that a high sequence identities more than 94% and 70% to Xanthomonas species and to Xyllela fastidiosa, respectively but a low sequence homology less than 30% to other bacterial species. The twitching motility forming a marginal fringe on PSA media was observed on colony of the wild-type strain KACC10331, but not in mutant HNU89K9. Wild-type Xoo cells formed a biofilm on the surface of the PVC plastic test tube, while the mutant strain HNU89K9 did not form a biofilm. The results suggest that the pilQ gene of X. oryzae pv. oryzae plays a critical role in pathogenicity, twitching motility, and biofilm formation. 相似文献
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8.
The rice host sensor, XA21, confers robust resistance to most strains of Xanthomonas oryzae pv. oryzae (Xoo), the casual agent of bacterial blight disease. Using in planta fluorescence imaging of Xoo strain PXO99Az expressing a green fluorescent protein (Xoo-gfp) we show that XA21 restricts Xoo spread at the point of infection. This noninvasive and quantitative method to measure spatial distribution of Xoo populations in planta facilitates detailed assessment of plant disease resistance. 相似文献
9.
Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, is known to produce phytotoxic polysaccharides. The extracellular polysaccharide (EPS)
was isolated from virulent (BXO1) and virulence-deficient gum G mutant (BXO1002) strains of X. oryzae pv. oryzae and characterized using fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR). Data from the FT-IR suggested
that the aldehyde (R-CHO) group and C=O of acid anhydride are present in BXO1 but absent in BXO1002. The 1H-NMR spectra showed the presence of an acetyl amine of hexose or pentose, free amines of glucose, an β-anomeric carbon of
hexose and pentose, hydrogen next to hydroxyl group, an acetyl amine of hexose and pentose in the polysaccharides of both
BXO1 and BXO1002, and the absence of α-anomeric carbon of hexose or pentose and the glucuronic acid in the polysaccharides
produced by BXO1002. The test for glucuronic acid also confirmed the absence of glucuronic acid in the polysaccharides of
BXO1002 and the presence glucuronic acid (32 μg/mg) in the polysaccharides produced by BXO1.
Received: 14 May 2002 / Accepted: 21 June 2002 相似文献
10.
11.
Shen Chen Zhanghui Huang Liexian Zeng Jianyuan Yang Qiongguang Liu Xiaoyuan Zhu 《Molecular breeding : new strategies in plant improvement》2008,22(3):433-441
Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a devastating disease in rice worldwide. The resistance gene Xa7, which provides dominant resistance against the pathogen with avirulence (Avr) gene AvrXa7, has proved to be durably resistant to BB. A set of SSR markers were selected from the “gramene” database based on the Xa7 gene initial mapping region on chromosome 6. These markers were used to construct a high-resolution genetic map of the chromosomal
region surrounding the Xa7 gene. An F2 mapping population with 721 highly susceptible individuals derived from a cross between the near isogenic lines (NILs) IRBB7
and IR24 were constructed to localize the Xa7 gene. In a primary analysis with eleven polymorphic SSR markers, Xa7 was located in approximately the 0.28-cM region. To walk closer to the target gene, recombinant F2 individuals were tested using newly developed STMS (sequence tagged microsatellite) markers. Finally, the Xa7 gene was mapped to a 0.21-cM interval between the markers GDSSR02 and RM20593. The Xa7-linked markers were landed on the reference sequence of cv. Nipponbare through bioinformatics analysis. A contig map corresponding
to the Xa7 gene was constructed. The target gene was assumed to span an interval of approximately 118.5-kb which contained a total of
fourteen genes released by the TIGR Genome Annotation Version 5.0. Candidate-gene analysis of Xa7 revealed that the fourteen genes encode novel domains that have no amino acid sequence similar to other cloned Xa(xa) genes.
Shen Chen and Zhanghui Huang are contributed equally to this work. 相似文献
12.
Mauricio Soto-Suárez Diana Bernal Carolina González Boris Szurek Romain Guyot Joe Tohme Valérie Verdier 《BMC microbiology》2010,10(1):170
Background
Bacterial leaf blight causes significant yield losses in rice crops throughout Asia and Africa. Although both the Asian and African strains of the pathogen, Xanthomonas oryzae pv. oryzae (Xoo), induce similar symptoms, they are nevertheless genetically different, with the African strains being more closely related to the Asian X. oryzae pv. oryzicola (Xoc). 相似文献13.
14.
A basidiomyetous yeast strain RO-203, which formed orange-red colored colonies, was isolated from a sample of paddy rice crops at the ripe stage in Japan. Morphological, physiological and biochemical characterization indicated that this strain belonged to the genus Rhodotorula. Molecular taxonomic analysis based on the 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequences showed that RO-203 represents an undescribed yeast species, for which the name Rhodotorula oryzae sp. nov. is proposed (type strain: AS 2.2363T = MAFF 516128T). The new species clustered in a branch together with Sakaguchia dacryoidea in phylogenetic trees based on the D1/D2 and ITS sequences. These two species differed by 2.3% and 12% nucleotide divergences in the D1/D2 and ITS regions, respectively. 相似文献
15.
Adachi T Ito J Kawata K Kaya M Ishida H Sahara H Hata Y Ogino C Fukuda H Kondo A 《Applied microbiology and biotechnology》2008,81(4):711-719
A novel cell-surface display system was constructed in Aspergillus oryzae. Each of the five genes encoding the putative cell-wall-localized protein from the A. oryzae genome was cloned and these cell-surface anchor functions were examined by fusion to the C-terminal of the green fluorescent
protein (GFP). Using the MP1 and CWP proteins as anchor proteins, GFP signals were strongly observed on the cell surface of
recombinant A. oryzae. When these proteins were used as anchor proteins for cell-surface display of β-glucosidase from A. oryzae, enzyme activity was detected on the cell surface. In particular, β-glucosidase activity of recombinant A. oryzae using MP1, a putative glycosylphosphatidylinositol (GPI) anchor protein was higher than CWP. Based on these results, it was
concluded that the MP1 protein can act as a GPI-anchor protein in A. oryzae, and the proposed cell-surface display system using MP1 allows for the display of heterogeneous and endogenous proteins. 相似文献
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17.
Liu X Yang Q Lin F Hua L Wang C Wang L Pan Q 《Molecular genetics and genomics : MGG》2007,278(4):403-410
Blast, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most devastating diseases of rice worldwide. The Chinese native cultivar (cv.) Q15 expresses the broad-spectrum
resistance to most of the isolates collected from China. To effectively utilize the resistance, three rounds of linkage analysis
were performed in an F2 population derived from a cross of Q15 and a susceptible cv. Tsuyuake, which segregated into 3:1 (resistant/susceptible)
ratio. The first round of linkage analysis employing simple sequence repeat (SSR) markers was carried out in the F2 population through bulked-segregant assay. A total of 180 SSR markers selected from each chromosome equally were surveyed.
The results revealed that only two polymorphic markers, RM247 and RM463, located on chromosome 12, were linked to the resistance
(R) gene. To further define the chromosomal location of the R gene locus, the second round of linkage analysis was performed using additional five SSR markers, which located in the region
anchored by markers RM247 and RM463. The locus was further mapped to a 0.27 cM region bounded by markers RM27933 and RM27940
in the pericentromeric region towards the short arm. For fine mapping of the R locus, seven new markers were developed in the smaller region for the third round of linkage analysis, based on the reference
sequences. The R locus was further mapped to a 0.18 cM region flanked by marker clusters 39M11 and 39M22, which is closest to, but away from
the Pita/Pita
2 locus by 0.09 cM. To physically map the locus, all the linked markers were landed on the respective bacterial artificial
chromosome clones of the reference cv. Nipponbare. Sequence information of these clones was used to construct a physical map
of the locus, in silico, by bioinformatics analysis. The locus was physically defined to an interval of ≈37 kb. To further
characterize the R gene, five R genes mapped near the locus, as well as 10 main R genes those might be exploited in the resistance breeding programs, were selected for differential tests with 475 Chinese
isolates. The R gene carrier Q15 conveys resistances distinct from those conditioned by the carriers of the 15 R genes. Together, this valuable R gene was, therefore, designated as Pi39(t). The sequence information of the R gene locus could be used for further marker-based selection and cloning.
Xinqiong Liu and Qinzhong Yang contributed equally to this work. 相似文献
18.
Pathogenesis-related (PR) proteins play an important role in the disease resistance response. To better understand the function
of rice PR proteins, we examined the expressions of ten PR proteins in rice leaves at different developmental stages with
or without the interaction between rice and Xanthomonas oryzae pv. oryzae (Xoo). The results showed that most of the PR proteins were expressed in rice leaves in normal growth conditions, suggesting that
they play a role in rice growth. Six out of ten PR proteins (PR1, PR2, PR3, PR4b, PR8, and PR-pha) showed enhanced expression
in Xa21-mediated resistance responses at late stages after inoculation with Xoo. The remaining four PR proteins (PR5, PR6, PR15, and PR16) did not show changes in expression in the resistance response.
The expressions of PR proteins in the resistance reaction were further compared with those in the susceptible reaction and
a mock treatment. Interestingly, several of the PR proteins were expressed at the highest levels in the susceptible reaction
and at the lowest levels in the mock treatment. Among the other four PR proteins, PR5 and PR16 showed changes in the abundance
only in the susceptible response, while PR6 and PR15 showed no detectable difference in expression. These data provide fundamental
knowledge about the expression of PR proteins in the interaction between rice and Xoo. 相似文献
19.
Michielse CB Salim K Ragas P Ram AF Kudla B Jarry B Punt PJ van den Hondel CA 《Molecular genetics and genomics : MGG》2004,271(4):499-510
Two transformation systems, based on the use of CaCl2/PEG and Agrobacterium tumefaciens, respectively, were developed for the zygomycete Rhizopus oryzae. Irrespective of the selection marker used, a pyr4 marker derived from R. niveus or a dominant amdS+ marker from Aspergillus nidulans, and irrespective of the configuration of the transforming DNA (linear or circular), the transformants obtained with the CaCl2/PEG transformation method were found to carry multiple copies of tandemly linked vector molecules, which failed to integrate into the genomic DNA. Furthermore, these transformants displayed low mitotic stability. In contrast, transformants obtained by Agrobacterium-mediated transformation were mitotically stable, even under non-selective conditions. Detailed analysis of these transformants revealed that the transforming DNA had integrated into the genome of R. oryzae at a single locus in independently obtained transformants. In addition, truncation of the transforming DNA was observed, resulting in the integration of the R. niveus pyr4 marker gene, but not the second gene located on the transferred DNA. Modification of the transforming DNA, resulting in partial resistance to restriction enzyme digestion, was observed in transformants obtained with the CaCl2/PEG transformation method, suggesting that a specific genome defence mechanism may exist in R. oryzae. It is likely that the unique mechanism used by A. tumefaciens to deliver its transferred DNA to its hosts facilitates bypass of the host defence mechanisms, thus allowing the DNA to integrate into the chromosomal genome.An erratum to this article can be found at
Communicated by C. P. Hollenberg 相似文献
20.
Erwinia amylovora causes fire blight of apple, pear, and other members of the Rosaceae family. The enzyme LuxS catalyzes the last step in the
production of autoinducer-2 (AI-2), a molecule implicated with quorum sensing in many bacterial species. It is now well recognized
that LuxS also plays a central role in sulfur metabolism and in the activated methyl cycle, which is responsible for the generation
of S-adenosyl-l-methionine. A research paper has reported that luxS is not involved with quorum sensing in Er. amylovora, but in our study, Er. amylovora strain NCPPB1665 (Ea1665) produced luxS-dependent extracellular AI-2 activity. Additionally, the maximal AI-2 activity occurred during late-exponential and early-stationary
growth phases and diminished during the stationary phase. The luxS mutant of Ea1665 was constructed, and the phenotypes of a defined luxS mutant have been characterized. Inactivation of luxS in Ea1665 impaired motility, extracellular polysaccharide (EPS) production, and tolerance for hydrogen peroxide, and reduced virulence
on pear leaves.
Yan Gao and Junxian Song contributed equally to this research. 相似文献