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Li R, Ren P, Zhang D, Cui P, Zhu G, Xian X, Tang J, Lu G. HpaP divergently regulates the expression of hrp genes in Xanthomonas oryzae pathovars oryzae and oryzicola. MOLECULAR PLANT PATHOLOGY 2023; 24:44-58. [PMID: 36260328 PMCID: PMC9742497 DOI: 10.1111/mpp.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
The bacterial pathogens Xanthomonas oryzae pathovars oryzae (Xoo) and oryzicola (Xoc) cause leaf blight and leaf streak diseases on rice, respectively. Pathogenesis is largely defined by the virulence genes harboured in the pathogen genome. Recently, we demonstrated that the protein HpaP of the crucifer pathogen Xanthomonas campestris pv. campestris is an enzyme with both ATPase and phosphatase activities, and is involved in regulating the synthesis of virulence factors and the induction of the hypersensitive response (HR). In this study, we investigated the role of HpaP homologues in Xoo and Xoc. We showed that HpaP is required for full virulence of Xoo and Xoc. Deletion of hpaP in Xoo and Xoc led to a reduction in virulence and alteration in the production of virulence factors, including extracellular polysaccharide and cell motility. Comparative transcriptomics and reverse transcription-quantitative PCR assays revealed that in XVM2 medium, a mimic medium of the plant environment, the expression levels of hrp genes (for HR and pathogenicity) were enhanced in the Xoo hpaP deletion mutant compared to the wild type. By contrast, in the same growth conditions, hrp gene expression was decreased in the Xoc hpaP deletion mutant compared to the wild type. However, an opposite expression pattern was observed when the pathogens grew in planta, where the expression of hrp genes was reduced in the Xoo hpaP mutant but increased in the Xoc hpaP mutant. These findings indicate that HpaP plays a divergent role in Xoo and Xoc, which may lead to the different infection strategies employed by these two pathogens.
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Affiliation(s)
- Rui‐Fang Li
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Pei‐Dong Ren
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Da‐Pei Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Ping Cui
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Gui‐Ning Zhu
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Xiao‐Yong Xian
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
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Mohsin A, Akyliyaevna KA, Zaman WQ, Hussain MH, Mohsin MZ, Al-Rashed S, Tan X, Tian X, Aida K, Tariq M, Haider MS, Khan IM, Niazi S, Zhuang Y, Guo M. Kinetically modelled approach of xanthan production using different carbon sources: A study on molecular weight and rheological properties of xanthan. Int J Biol Macromol 2021; 193:1226-1236. [PMID: 34743029 DOI: 10.1016/j.ijbiomac.2021.10.163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/15/2021] [Accepted: 10/21/2021] [Indexed: 11/15/2022]
Abstract
The present study emphasizes improving the overall yield, productivity and quality of xanthan by Xanthomonas campestris using different carbon sources via optimizing the fermentation media and kinetic modelling work. After optimization, six carbon sources and one nitrogen source were selected for xanthan production in 5 L bioreactor. Kinetic modelling was applied to assess the experimental fermentation data and to check its influence on scale-up production. In this work, xanthan production reached 40.65 g/L with a growth-associated rate constant (α) of 2.831, and highest specific growth rate (μm) of 0.37/h while using maltose as the sole carbon source. Furthermore, rheological properties were determined, and Herschel-Bulkley model was employed to assess the experimental data. Interestingly, xanthan obtained from sucrose and glucose showed the highest yield stress (τ0) of 12.50 ± 0.31 and 7.17 ± 0.21. Moreover, the highest xanthan molecular weight of 3.53 × 107 and 3.25 × 107 g/mol were also found with sucrose and glucose. At last, the proposed mechanism of sugar metabolism and xanthan biosynthesis pathway were described. Conclusively, maltose appeared as the best carbon source for maximum xanthan production: while sucrose and glucose gave qualitatively best results. In short, this systematically modelled approach maximizes the potential output and provides a solid base for continuous cultivation of xanthan at large-scale production.
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Affiliation(s)
- Ali Mohsin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Kanagat Akbota Akyliyaevna
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Department of Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
| | - Waqas Qamar Zaman
- Institute of Environmental Sciences and Engineering, School of Civil and Environmental Engineering, National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan
| | - Muhammad Hammad Hussain
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Muhammad Zubair Mohsin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Sarah Al-Rashed
- Department of Botany and Microbiology, College of Science, King Saud University, P.O 2455, Riyadh 11451, Saudi Arabia
| | - Xin Tan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Xiwei Tian
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Kistaubayeva Aida
- Department of Biotechnology, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan
| | - Muhammad Tariq
- Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Muhammad Salman Haider
- Applied Science Research Institute, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Department of Chemical Engineering, University of Gujrat, HH Campus, 50700 Gujrat, Pakistan
| | - Imran Mahmood Khan
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
| | - Sobia Niazi
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China.
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3
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Zhou T, Song YC, Feng MQ, Tan RX. Cloning, expression and biochemical characterization of UDP-glucose 6-dehydrogenase, a key enzyme in the biosynthesis of an anti-tumor polysaccharide from the marine fungus Phoma herbarum YS4108. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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4
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Sato K, Kido N, Murakami Y, Hoover CI, Nakayama K, Yoshimura F. Lipopolysaccharide biosynthesis-related genes are required for colony pigmentation of Porphyromonas gingivalis. MICROBIOLOGY-SGM 2009; 155:1282-1293. [PMID: 19332829 DOI: 10.1099/mic.0.025163-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The periodontopathic bacterium Porphyromonas gingivalis forms pigmented colonies when incubated on blood agar plates as a result of accumulation of mu-oxo haem dimer on the cell surface. Gingipain-adhesin complexes are responsible for production of mu-oxo haem dimer from haemoglobin. Non-pigmented mutants (Tn6-5, Tn7-1, Tn7-3 and Tn10-4) were isolated from P. gingivalis by Tn4351 transposon mutagenesis [Hoover & Yoshimura (1994), FEMS Microbiol Lett 124, 43-48]. In this study, we found that the Tn6-5, Tn7-1 and Tn7-3 mutants carried Tn4351 DNA in a gene homologous to the ugdA gene encoding UDP-glucose 6-dehydrogenase, a gene encoding a putative group 1 family glycosyltransferase and a gene homologous to the rfa gene encoding ADP heptose-LPS heptosyltransferase, respectively. The Tn10-4 mutant carried Tn4351 DNA at the same position as that for Tn7-1. Gingipain activities associated with cells of the Tn7-3 mutant (rfa) were very weak, whereas gingipain activities were detected in the culture supernatants. Immunoblot and mass spectrometry analyses also revealed that gingipains, including their precursor forms, were present in the culture supernatants. A lipopolysaccharide (LPS) fraction of the rfa deletion mutant did not show the ladder pattern that was usually seen for the LPS of the wild-type P. gingivalis. A recombinant chimera gingipain was able to bind to an LPS fraction of the wild-type P. gingivalis in a dose-dependent manner. These results suggest that the rfa gene product is associated with biosynthesis of LPS and/or cell-surface polysaccharides that can function as an anchorage for gingipain-adhesin complexes.
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Affiliation(s)
- Keiko Sato
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Nobuo Kido
- Division of Plant Growth Physiology, Nagoya University Graduate School of Biological Sciences, Furou-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yukitaka Murakami
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Charles I Hoover
- University of California, San Francisco, CA 94143-0512, USA.,Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Nagasaki 852-8588, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan
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5
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Vorhölter FJ, Schneiker S, Goesmann A, Krause L, Bekel T, Kaiser O, Linke B, Patschkowski T, Rückert C, Schmid J, Sidhu VK, Sieber V, Tauch A, Watt SA, Weisshaar B, Becker A, Niehaus K, Pühler A. The genome of Xanthomonas campestris pv. campestris B100 and its use for the reconstruction of metabolic pathways involved in xanthan biosynthesis. J Biotechnol 2008; 134:33-45. [PMID: 18304669 DOI: 10.1016/j.jbiotec.2007.12.013] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 12/04/2007] [Accepted: 12/24/2007] [Indexed: 10/22/2022]
Abstract
The complete genome sequence of the Xanthomonas campestris pv. campestris strain B100 was established. It consisted of a chromosome of 5,079,003bp, with 4471 protein-coding genes and 62 RNA genes. Comparative genomics showed that the genes required for the synthesis of xanthan and xanthan precursors were highly conserved among three sequenced X. campestris pv. campestris genomes, but differed noticeably when compared to the remaining four Xanthomonas genomes available. For the xanthan biosynthesis genes gumB and gumK earlier translational starts were proposed, while gumI and gumL turned out to be unique with no homologues beyond the Xanthomonas genomes sequenced. From the genomic data the biosynthesis pathways for the production of the exopolysaccharide xanthan could be elucidated. The first step of this process is the uptake of sugars serving as carbon and energy sources wherefore genes for 15 carbohydrate import systems could be identified. Metabolic pathways playing a role for xanthan biosynthesis could be deduced from the annotated genome. These reconstructed pathways concerned the storage and metabolization of the imported sugars. The recognized sugar utilization pathways included the Entner-Doudoroff and the pentose phosphate pathway as well as the Embden-Meyerhof pathway (glycolysis). The reconstruction indicated that the nucleotide sugar precursors for xanthan can be converted from intermediates of the pentose phosphate pathway, some of which are also intermediates of glycolysis or the Entner-Doudoroff pathway. Xanthan biosynthesis requires in particular the nucleotide sugars UDP-glucose, UDP-glucuronate, and GDP-mannose, from which xanthan repeat units are built under the control of the gum genes. The updated genome annotation data allowed reconsidering and refining the mechanistic model for xanthan biosynthesis.
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Affiliation(s)
- Frank-Jörg Vorhölter
- Universität Bielefeld, Biologie VI (Genetik), Universitätsstr. 25, D-33615 Bielefeld, Germany
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6
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da Silva FR, Vettore AL, Kemper EL, Leite A, Arruda P. Fastidian gum: the Xylella fastidiosa exopolysaccharide possibly involved in bacterial pathogenicity. FEMS Microbiol Lett 2001; 203:165-71. [PMID: 11583843 DOI: 10.1111/j.1574-6968.2001.tb10836.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The Gram-negative bacterium Xylella fastidiosa was the first plant pathogen to be completely sequenced. This species causes several economically important plant diseases, including citrus variegated chlorosis (CVC). Analysis of the genomic sequence of X. fastidiosa revealed a 12 kb DNA fragment containing an operon closely related to the gum operon of Xanthomonas campestris. The presence of all genes involved in the synthesis of sugar precursors, existence of exopolysaccharide (EPS) production regulators in the genome, and the absence of three of the X. campestris gum genes suggested that X. fastidiosa is able to synthesize an EPS different from that of xanthan gum. This novel EPS probably consists of polymerized tetrasaccharide repeating units assembled by the sequential addition of glucose-1-phosphate, glucose, mannose and glucuronic acid on a polyprenol phosphate carrier.
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Affiliation(s)
- F R da Silva
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6010, CEP 13083-970, Campinas, São Paulo, Brazil
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7
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Chang KW, Weng SF, Tseng YH. UDP-glucose dehydrogenase gene of Xanthomonas campestris is required for virulence. Biochem Biophys Res Commun 2001; 287:550-5. [PMID: 11554764 DOI: 10.1006/bbrc.2001.5591] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Xanthomonas campestris pv. campestris (Xc) is the casual agent of black rot in crucifers. The Xc gene (udgH) coding for UDP-glucose dehydrogenase, an enzyme catalyzing the conversion of UDP-glucose to UDP-glucuronic acid, was previously shown to be required for the biosynthesis of xanthan gum, a substance necessary for the bacterium to cause disease. In this study, the transcription start site of the udgH was determined and the promoter activity monitored by the xylE reporter system indicated that expression of the udgH increases following cell growth and that the udgH gene may possess a second promoter that is responsive to stationary-phase change retaining high levels of expression. Results of Southern hybridization suggest that the udgH gene may be ubiquitous in Xanthomonas, coincident with the notion that members of this genus are capable of xanthan gum biosynthesis. Mutation of the udgH gene in Xc and X. campestris pv. vesicatoria, the casual agent of leaf spot in pepper and tomato, was found to cause a loss of virulence.
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Affiliation(s)
- K W Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
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8
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Tseng YH, Choy KT, Hung CH, Lin NT, Liu JY, Lou CH, Yang BY, Wen FS, Weng SF, Wu JR. Chromosome map of Xanthomonas campestris pv. campestris 17 with locations of genes involved in xanthan gum synthesis and yellow pigmentation. J Bacteriol 1999; 181:117-25. [PMID: 9864320 PMCID: PMC103539 DOI: 10.1128/jb.181.1.117-125.1999] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
No plasmid was detected in Xanthomonas campestris pv. campestris 17, a strain of the causative agent of black rot in cruciferous plants isolated in Taiwan. Its chromosome was cut by PacI, PmeI, and SwaI into five, two, and six fragments, respectively, and a size of 4.8 Mb was estimated by summing the fragment lengths in these digests. Based on the data obtained from partial digestion and Southern hybridization using probes common to pairs of the overlapping fragments or prepared from linking fragments, a circular physical map bearing the PacI, PmeI, and SwaI sites was constructed for the X. campestris pv. campestris 17 chromosome. Locations of eight eps loci involved in exopolysaccharide (xanthan gum) synthesis, two rrn operons each possessing an unique I-CeuI site, one pig cluster required for yellow pigmentation, and nine auxotrophic markers were determined, using mutants isolated by mutagenesis with Tn5(pfm)CmKm. This transposon contains a polylinker with sites for several rare-cutting restriction endonucleases located between the chloramphenicol resistance and kanamycin resistance (Kmr) genes, which upon insertion introduced additional sites into the chromosome. The recA and tdh genes, with known sequences, were mapped by tagging with the polylinker-Kmr segment from Tn5(pfm)CmKm. This is the first map for X. campestris and would be useful for genetic studies of this and related Xanthomonas species.
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Affiliation(s)
- Y H Tseng
- Institute of Molecular Biology and Department of Botany, National Chung Hsing University, Taichung 402, Taiwan.
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9
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Kereszt A, Kiss E, Reuhs BL, Carlson RW, Kondorosi A, Putnoky P. Novel rkp gene clusters of Sinorhizobium meliloti involved in capsular polysaccharide production and invasion of the symbiotic nodule: the rkpK gene encodes a UDP-glucose dehydrogenase. J Bacteriol 1998; 180:5426-31. [PMID: 9765575 PMCID: PMC107592 DOI: 10.1128/jb.180.20.5426-5431.1998] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The production of exopolysaccharide (EPS) was shown to be required for the infection process by rhizobia that induce the formation of indeterminate nodules on the roots of leguminous host plants. In Sinorhizobium meliloti (also known as Rhizobium meliloti) Rm41, a capsular polysaccharide (KPS) analogous to the group II K antigens of Escherichia coli can replace EPS during symbiotic nodule development and serve as an attachment site for the strain-specific bacteriophage phi16-3. The rkpA to -J genes in the chromosomal rkp-1 region code for proteins that are involved in the synthesis, modification, and transfer of an as-yet-unknown lipophilic molecule which might function as a specific lipid carrier during KPS biosynthesis. Here we report that with a phage phi16-3-resistant population obtained after random Tn5 mutagenesis, we have identified novel mutants impaired in KPS production by genetic complementation and biochemical studies. The mutations represent two novel loci, designated the rkp-2 and rkp-3 regions, which are required for the synthesis of rhizobial KPS. The rkp-2 region harbors two open reading frames (ORFs) organized in monocistronic transcription units. Although both genes are required for normal lipopolysaccharide production, only the second one, designated rkpK, is involved in the synthesis of KPS. We have demonstrated that RkpK possesses UDP-glucose dehydrogenase activity, while the protein product of ORF1 might function as a UDP-glucuronic acid epimerase.
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Affiliation(s)
- A Kereszt
- Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, H-6701 Szeged, Hungary
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10
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Chang KH, Wen FS, Tseng TT, Lin NT, Yang MT, Tseng YH. Sequence analysis and expression of the filamentous phage phi Lf gene I encoding a 48-kDa protein associated with host cell membrane. Biochem Biophys Res Commun 1998; 245:313-8. [PMID: 9571147 DOI: 10.1006/bbrc.1998.8432] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One viral strand of phi Lf, a filamentous phage of Xanthomonas campestris pv.campestris, the open reading frame (ORF440) behind gene VI was identified as gene I. This gene codes for pI protein (440 aa, 48 kDa) which was shown to be membrane-bound in the phi Lf-infected host cell by Western blot analysis using the antibody raised against the protein expressed in Escherichia coli. Its predicted amino acid sequence has a nucleotide-binding motif in the N-terminal 97 aa and a membrane-spanning domain (aa 221 to 236). These structural features are characteristic of pIs of several filamentous phages which are transmembrane proteins required for phage assembly. Thus far, nine phi Lf genes have been identified which are organized in the order GII-gX-gV-gVII-gIX-gVIII-gIII-gVI-gI, similar to the genome organization of E. coli filamentous phages.
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Affiliation(s)
- K H Chang
- Institute of Molecular Biology, National Chung Hsing University, Taiwan
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11
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Weng SF, Liu YS, Lin JW, Tseng YH. Transcriptional analysis of the threonine dehydrogenase gene of Xanthomonas campestris. Biochem Biophys Res Commun 1997; 240:523-9. [PMID: 9398597 DOI: 10.1006/bbrc.1997.7686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The nucleotide sequence has previously been determined for the Xanthomonas campestris pv. campestris gene coding for threonine dehydrogenase (tdh). Flanking this gene are the upstream region possessing promoter activity and the downstream perfect inverted repeat having potential to form a stem-loop structure which resembles a transcription terminator. In addition, Northern blot analysis suggested the transcript of this gene to be monocistronic. In the present study, the essential region for promoter activity was narrowed down to a stretch of 57 bp which still retained 84% of the promoter activity. The first nucleotide to be transcribed is the guanosine at 30 nt upstream from the proposed tdh start codon. The putative terminator exhibited transcriptional termination activity bidirectionally in both Escherichia coli and X. campestris. These observations indicate that the transcriptional structure of X. campestris tdh is different from that of E. coli where tdh and kbl are organized into the tdh operon. Furthermore, the expression of tdh in X. campestris is repressed by leucine, a situation different from that in E. coli where leucine induces the expression of tdh operon.
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MESH Headings
- Alcohol Oxidoreductases/chemistry
- Alcohol Oxidoreductases/genetics
- Base Sequence
- Blotting, Northern
- Codon, Initiator/genetics
- Escherichia coli/chemistry
- Escherichia coli/genetics
- Gene Expression Regulation, Bacterial/genetics
- Genes, Bacterial/genetics
- Leucine/pharmacology
- Molecular Sequence Data
- Nucleic Acid Conformation
- Peptide Chain Initiation, Translational/genetics
- Plasmids
- Promoter Regions, Genetic/genetics
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- Repetitive Sequences, Nucleic Acid/genetics
- Sequence Analysis, DNA
- Terminator Regions, Genetic/genetics
- Transcription, Genetic/genetics
- Xanthomonas campestris/enzymology
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Affiliation(s)
- S F Weng
- Institute of Molecular Biology, National Chung Hsing University, Taiwan, Republic of China
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12
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Liu TJ, Wen FS, Tseng TT, Yang MT, Lin NT, Tseng YH. Identification of gene VI of filamentous phage phi Lf coding for a 10-kDa minor coat protein. Biochem Biophys Res Commun 1997; 239:752-5. [PMID: 9367841 DOI: 10.1006/bbrc.1997.7548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
ORF95 in the filamentous phage phi Lf genome, locating behind gIII, was identified to be the gene (gVI) coding for minor coat protein pVI (95 amino acids, 10,245 dal). It was shown to be virion associated by Western blot analysis of chloroform-treated phage particles. Computer analysis predicted two transmembrane regions for this protein. Since no signal peptide was suggested and the size estimated by SDS-polyacrylamide gel electrophoresis matches that deduced from nucleotide sequence, it appears to be incorporated into the phage particle as its primary translational product. After completion of this study, eight genes organizing into an order of gVII-gX-gV-gVII-gIX-gIII-gIII-gVI have been identified for phi Lf.
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Affiliation(s)
- T J Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
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13
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Liu YS, Tseng YH, Lin JW, Weng SF. Molecular characterization of the gene coding for threonine dehydrogenase in Xanthomonas campestris. Biochem Biophys Res Commun 1997; 235:300-5. [PMID: 9199186 DOI: 10.1006/bbrc.1997.6778] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Xanthomonas campestris pv. campestris 17 gene tdh, which codes for the threonine dehydrogenase (TDH), was cloned and sequenced. The deduced gene product, a polypeptide consisting of 340 amino acids (Mr = 37,048), has 63.5% identity to the E. coli TDH in amino acid sequence and shares residue conservation with the alcohol/polyol dehydrogenases from different organisms. TDH activity was not detectable in the tdh mutant constructed by gene replacement; however, the enzyme activity in the mutant complemented in trans by a plasmid containing the complete tdh sequence was increased by 15 folds over Xc17. Northern blot analysis detected an mRNA with a size similar to that of the Xc17 tdh coding region, suggesting that the tdh gene-containing transcript may be monocistronic.
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Affiliation(s)
- Y S Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, Republic of China
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Chou FL, Chou HC, Lin YS, Yang BY, Lin NT, Weng SF, Tseng YH. The Xanthomonas campestris gumD gene required for synthesis of xanthan gum is involved in normal pigmentation and virulence in causing black rot. Biochem Biophys Res Commun 1997; 233:265-9. [PMID: 9144435 DOI: 10.1006/bbrc.1997.6365] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A cloned 4.1-kb EcoRI fragment from Xanthomonas campestris pv. campestris was previously shown to complement the non-mucoid mutant P22 and increase xanthan gum production after being transformed into the wild-type strain Xc17. The gene responsible for these effects was identified, sequenced, and shown to be the gumD gene which has previously been proposed to encode glucose transferase activity, an enzyme required for adding the first glucose residue to the isoprenoid glycosyl carrier lipid during xanthan synthesis. A gumD mutant, isolated from Xc17 by gene replacement, was shown to possess altered pigment xanthomonadin profiles and exhibit reduced virulence in causing black rot in broccoli. This study appears to be the first to demonstrate that interruption of a gene required for xanthan synthesis can lead to reduced virulence of X. campestris.
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Affiliation(s)
- F L Chou
- Department of Botany and Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, Republic of China
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15
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Tseng YS, Yu CT, Tseng YH, Yang MT. Cloning, sequencing, and expression of the rpoD gene encoding the primary sigma factor of Xanthomonas campestris. Biochem Biophys Res Commun 1997; 232:712-8. [PMID: 9126341 DOI: 10.1006/bbrc.1997.6272] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A DNA fragment encoding the primary sigma factor from Xanthomonas campestris pv. campestris was cloned and sequenced. The gene (rpoD) encodes a polypeptide of 622 amino acids with a calculated MW of 70,700. The deduced amino acid sequence exhibits extensive sequence homology to the conserved regions of the primary sigma factors from bacteria. The gene product expressed in Escherichia coli, detected by Western blot analysis, had a MW similar to that estimated for the purified protein in SDS-PAGE. The NH2-terminal amino acid sequence determined chemically matched with that deduced from the nucleotide sequence of the rpoD gene. The calculated pI value (9.31) for the X. campestris primary sigma factor is much higher than the values observed for the analogous proteins from other bacteria.
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Affiliation(s)
- Y S Tseng
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, Republic of China
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16
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Increase of xanthan production by self-cloning of a 3.0-kb EcoRI-KpnI chromosomal fragment in Xanthomonas campestris. Biotechnol Lett 1996. [DOI: 10.1007/bf00129959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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