scholarly journals Mutagenesis of all Eight avr Genes in Xanthomonas campestris pv. campestris Had No Detected Effect on Pathogenicity, But One avr Gene Affected Race Specificity

2005 ◽  
Vol 18 (12) ◽  
pp. 1306-1317 ◽  
Author(s):  
Adriana Castañeda ◽  
Joseph D. Reddy ◽  
Basma El-Yacoubi ◽  
Dean W. Gabriel
Keyword(s):  
Xanthomonas Campestris ◽  
Subtractive Hybridization ◽  
Wild Type ◽  
Differential Host ◽  
Reading Frame ◽  
Race Specificity ◽  
Avr Gene ◽  
Xanthomonas Campestris Pv Campestris ◽  
Avr Genes ◽  
Insertion Mutations

Suppression subtractive hybridization (SSH) was used to identify genes present in the systemic crucifer black rot pathogen Xanthomonas campestris pv. campestris 528T but missing from the nonsystemic crucifer leaf spot pathogen, X. campestris pv. armoraciae 417. Among the DNA fragments unique to 528T was Xcc2109, one of eight putative avr genes identified in the published 528T genome (NC_003902). Individual and sequential deletion, insertion mutations, or both of all eight 528T avr gene loci were made, but no change in pathogenicity was observed with any combination of avr mutations, including a strain with all eight avr genes deleted. However, insertion or deletion mutants affecting the Xcc2109 locus lost avirulence (i.e., became virulent) on Florida Mustard, an X. campestris pv. campestris race-determining, differential host. The Xcc2109 open reading frame as annotated was cloned and found to be nonfunctional. A longer gene, encompassing Xcc2109 and here designated avrXccFM, was cloned and found to complement the Xcc2109 mutants and to confer avirulence to two additional wild-type X. campestris pv. campestris strains, thereby changing their races. Resistance in Florida Mustard to 528T strains carrying avrXccFM occurred without a typical hypersensitive response (HR) on leaves, although a vascular HR was observed in seedlings.

scholarly journals Glyceraldehyde-3-phosphate dehydrogenase of Xanthomonas campestris pv. campestris is required for extracellular polysaccharide production and full virulence

Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1602-1612 ◽  
Author(s):  
Guang-Tao Lu ◽  
Jia-Ri Xie ◽  
Lei Chen ◽  
Jiang-Ru Hu ◽  
Shi-Qi An ◽  
...  
Keyword(s):  
Carbon Source ◽  
Xanthomonas Campestris ◽  
Sole Carbon Source ◽  
Extracellular Polysaccharide ◽  
Open Reading Frame ◽  
Deficient Mutant ◽  
Wild Type ◽  
Reading Frame ◽  
Phosphofructokinase Activity ◽  
Xanthomonas Campestris Pv Campestris

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays an important role in glucose catabolism, converting glyceraldehyde 3-phosphates to 1,3-bisphosphoglycerates. Open reading frame (ORF) XC_0972 in the genome of Xanthomonas campestris pv. campestris (Xcc) strain 8004 is the only ORF in this strain annotated to encode a GAPDH. In this work, we have demonstrated genetically that this ORF encodes a unique GAPDH in Xcc strain 8004, which seems to be constitutively expressed. A GAPDH-deficient mutant could still grow in medium with glucose or other sugars as the sole carbon source, and no phosphofructokinase activity was detectable in strain 8004. These facts suggest that Xcc may employ the Entner–Doudoroff pathway, but not glycolysis, to utilize glucose. The mutant could not utilize pyruvate as sole carbon source, whereas the wild-type could, implying that the GAPDH of Xcc is involved in gluconeogenesis. Furthermore, inactivation of the Xcc GAPDH resulted in impairment of bacterial growth and virulence in the host plant, and reduction of intracellular ATP and extracellular polysaccharide (EPS). This reveals that GAPDH is required for EPS production and full pathogenicity of Xcc.

scholarly journals XpsG, the major pseudopilin in Xanthomonas campestris pv. campestris, forms a pilus-like structure between cytoplasmic and outer membranes

2002 ◽  
Vol 365 (1) ◽  
pp. 205-211 ◽  
Author(s):  
Nien-Tai HU ◽  
Wei-Ming LEU ◽  
Meng-Shiunn LEE ◽  
Avon CHEN ◽  
Shu-Chung CHEN ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Klebsiella Oxytoca ◽  
Subcellular Fractionation ◽  
Soluble Form ◽  
Wild Type ◽  
Outer Membranes ◽  
Extracellular Milieu ◽  
Large Complex ◽  
Xanthomonas Campestris Pv Campestris

GspG, -H, -I, -J and -K proteins are members of the pseudopilin family. They are the components required for the type II secretion pathway, which translocates proteins across the outer membrane of Gram-negative bacteria to the extracellular milieu. They were predicted to form a pilus-like structure, and this has been shown for PulG of Klebsiella oxytoca by using electron microscopy. In the present study, we performed biochemical analyses of the XpsG protein of Xanthomonas campestris pv. campestris and observed that it is a pillar-like structure spanning the cytoplasmic and outer membranes. Subcellular fractionation revealed a soluble form (SF) of XpsG, in addition to the membrane form. Chromatographic analysis of SF XpsG in the absence of a detergent indicated that it is part of a large complex (>440kDa). In vitro studies indicated that XpsG is prone to aggregate in the absence of a detergent. We isolated and characterized a non-functional mutant defective in forming the large complex. It did not interfere with the function of wild-type XpsG and was not detectable in the SF. Moreover, unlike wild-type XpsG, which was distributed in both the cytoplasmic and outer membranes, it appeared only in the cytoplasmic membrane. When wild-type XpsG was co-expressed with His6-tagged XpsH but not with untagged XpsH, SF XpsG bound to nickel and co-eluted with XpsH. This result suggests the presence of other pseudopilin components in the XpsG-containing large-sized molecules.

scholarly journals 5 S rRNA is involved in fidelity of translational reading frame.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 95-105
Author(s):  
J D Dinman ◽  
R B Wickner
Keyword(s):  
Rdna Locus ◽  
Wild Type ◽  
Lacz Reporter ◽  
Lacz Expression ◽  
Lacz Reporter Gene ◽  
Ribosomal Frameshifting ◽  
Reading Frame ◽  
Episomal Vector ◽  
Electrophoretic Mobilities ◽  
Insertion Mutations

Abstract Chromosomal mutants (maintenance of frame = mof) in which the efficiency of -1 ribosomal frameshifting is increased can be isolated using constructs in which lacZ expression is dependent upon a -1 shift of reading frame. We isolate a new mof mutation, mof9, in Saccharomyces cerevisiae and show that it is complemented by both single and multi-copy 5 S rDNA clones. Two independent insertion mutations in the rDNA locus (rDNA::LEU2 and rDNA::URA3) also display the Mof- phenotype and are also complemented by single and multi-copy 5 S rDNA clones. Mutant 5 S rRNAs expressed from a plasmid as 20-50% of total 5 S rRNA in a wild-type host also induced the Mof- phenotype. The increase in frameshifting is greatest when the lacZ reporter gene is expressed on a high copy, episomal vector. No differences were found in 5 S rRNA copy number or electrophoretic mobilities in mof9 strains. Both mof9 and rDNA::LEU2 increase the efficiency of +1 frameshifting as well but have no effect on readthrough of UAG or UAA termination codons, indicating that not all translational specificity is affected. These data suggest a role for 5 S rRNA in the maintenance of frame in translation.

scholarly journals DsbB Is Required for the Pathogenesis Process of Xanthomonas campestris pv. campestris

2008 ◽  
Vol 21 (8) ◽  
pp. 1036-1045 ◽  
Author(s):  
Bo-Le Jiang ◽  
Jiao Liu ◽  
Li-Feng Chen ◽  
Ying-Ying Ge ◽  
Xiao-Hong Hang ◽  
...  
Keyword(s):  
Disulfide Bond ◽  
Xanthomonas Campestris ◽  
Bond Formation ◽  
Disulfide Bond Formation ◽  
In Planta ◽  
Secretion Systems ◽  
Reading Frame ◽  
Type Iii Secretion Systems ◽  
Rot Disease ◽  
Xanthomonas Campestris Pv Campestris

The DsbA/DsbB oxidation pathway is one of the two pathways that catalyze disulfide bond formation of proteins in the periplasm of gram-negative bacteria. It has been demonstrated that DsbA is essential for multiple virulence factors of several animal bacterial pathogens. In this article, we present genetic evidence to show that the open reading frame XC_3314 encodes a DsbB protein that is involved in disulfide bond formation in periplasm of Xanthomonas campestris pv. campestris, the causative agent of crucifer black rot disease. The dsbB mutant of X. campestris pv. campestris exhibited attenuation in virulence, hypersensitive response, cell motility, and bacterial growth in planta. Furthermore, mutation in the dsbB gene resulted in ineffective type II and type III secretion systems as well as flagellar assembly. These findings reveal that DsbB is required for the pathogenesis process of X. campestris pv. campestris.

scholarly journals Xanthomonas oryzae pv. Oryzae Avirulence Genes Contribute Differently and Specifically to Pathogen Aggressiveness

2000 ◽  
Vol 13 (12) ◽  
pp. 1322-1329 ◽  
Author(s):  
Jianfa Bai ◽  
Seong-Ho Choi ◽  
Grisel Ponciano ◽  
Hei Leung ◽  
Jan E. Leach
Keyword(s):  
Gene Family ◽  
Type Strain ◽  
Wild Type Strain ◽  
Family Members ◽  
Xanthomonas Oryzae ◽  
Wild Type ◽  
Homologous Genes ◽  
Avr Gene ◽  
Avr Genes ◽  
Pathogen Aggressiveness

Genomic copies of three Xanthomonas oryzae pv. oryzae avirulence (avr) genes, avrXa7, avrXa10, and avrxa5, and four homologous genes, aB3.5, aB3.6, aB4.3, and aB4.5, were mutagenized individually or in combination to study the roles of avr genes in one component of pathogen fitness, i.e., aggressiveness or the amount of disease X. oryzae pv. oryzae causes in susceptible rice lines. These X. oryzae pv. oryzae genes are members of the highly related Xanthomonas avrBs3 gene family. Compared to the wild-type strain, X. oryzae pv. oryzae strains with mutations in avrXa7, avrxa5, and the four homologous genes caused shorter lesions on rice line IR24, which contains no resistance genes relevant to the wild-type strain. The contribution of each gene to lesion length varied, with avrXa7 contributing the most and avrXa10 showing no measurable effect on aggressiveness. The functional, plasmidborne copies of avrXa7, aB4.5, and avrxa5 restored aggressiveness only to strains with mutations in avrXa7, aB4.5, and avrxa5, respectively. Mutations in avrXa7 were not complemented by plasmids carrying any other avr gene family members. These data indicate that some, but not all, avr family members contribute to pathogen aggressiveness and that the contributions are quantitatively different. Furthermore, despite their sequence similarity, the aggressiveness functions of these gene family members are not interchangeable. The results suggest that selection and pyramiding resistance genes can be guided by the degree of fitness penalty that is empirically determined in avr gene mutations.

scholarly journals The Zur of Xanthomonas campestris Is Involved in Hypersensitive Response and Positively Regulates the Expression of the hrp Cluster Via hrpX But Not hrpG

2009 ◽  
Vol 22 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Dong-Liang Huang ◽  
Dong-Jie Tang ◽  
Qing Liao ◽  
Xiao-Qian Li ◽  
Yong-Qiang He ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Hypersensitive Response ◽  
Reverse Transcription ◽  
Xanthomonas Campestris ◽  
Zinc Homeostasis ◽  
Wild Type ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Xanthomonas Campestris Pv Campestris

In bacteria, Zur is a key regulator for zinc homeostasis. Our previous work has shown that, in the phytopathogen Xanthomonas campestris pv. campestris, in addition to regulating zinc homeostasis, Zur is essential for full virulence. Here, we demonstrate that the X. campestris pv. campestris Zur is involved in hypersensitive response (HR) and positively regulates the transcription of hrpA to hrpF operons and hrpX but not hrpG. Constitutively expressing hrpX but not hrpG in the zur mutant could bypass the requirement of Zur for the expression of hrpA to hrpF operons and the induction of wild-type HR, indicating that Zur controls the expression of hrp cluster via hrpX. Promoter-gusA reporter and semiquantitative reverse-transcription polymerase chain reaction analyses revealed that HrpG controls the expression of hrpX and HrpX regulates the expression of all the six hrp operons (hrpA to hrpF) in X. campestris pv. campestris.

scholarly journals Identification of a Pathogenicity Locus, rpfA, in Erwinia carotovora subsp. carotovora That Encodes a Two-Component Sensor-Regulator Protein

1997 ◽  
Vol 10 (3) ◽  
pp. 407-415 ◽  
Author(s):  
Reid D. Frederick ◽  
Jiliang Chiu ◽  
Jeffrey L. Bennetzen ◽  
Autar K. Handa
Keyword(s):  
Xanthomonas Campestris ◽  
Genetic Locus ◽  
Cellulase Activity ◽  
Pectate Lyase ◽  
Erwinia Carotovora ◽  
Cellulase Production ◽  
Extracellular Protease ◽  
Wild Type ◽  
Reading Frame ◽  
Two Component

A mutant of Erwinia carotovora subsp. carotovora, AH2552, created by a Mud1 insertion was found to be reduced in plant pathogenicity and deficient in extracellular protease and cellulase activity, although it produced normal levels of pectate lyase and polygalacturonase. A cosmid clone, pEC462, was isolated from a wild-type E. carotovora subsp. carotovora DNA library that concomitantly restored pathogenicity and protease and cellulase activities of AH2552 to wild-type levels when present in trans. The genetic locus that was disrupted in AH2552 by insertion of Mud1 has been designated rpfA, for regulator of pathogenicity factors. Sequencing of the rpfA region identified an open reading frame of 2,787 bp, and the predicted 929-amino acid polypeptide shared high identity with several two-component sensor-regulator proteins: BarA from Escherichia coli, ApdA from Pseudomonas fluorescens, PheN from P. tolaasii, RepA from P. viridiflava, LemA from P. syringae pv. syringae, and RpfC from Xanthomonas campestris pv. campestris. The RpfA locus described in this study encodes a putative sensor kinase protein that is involved in both extracellular protease and cellulase production and the pathogenicity of E. carotovora subsp. carotovora on potato tubers.

scholarly journals The Zinc Uptake Regulator Zur Is Essential for the Full Virulence of Xanthomonas campestris pv. campestris

2005 ◽  
Vol 18 (7) ◽  
pp. 652-658 ◽  
Author(s):  
Dong-Jie Tang ◽  
Xiang-Jiang Li ◽  
Yong-Qiang He ◽  
Jia-Xun Feng ◽  
Baoshan Chen ◽  
...  
Keyword(s):  
Type Strain ◽  
Xanthomonas Campestris ◽  
Wild Type Strain ◽  
Extracellular Polysaccharide ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Uptake System ◽  
Rich Medium ◽  
Wild Type ◽  
Xanthomonas Campestris Pv Campestris

Zur is a regulator of the high-affinity zinc uptake system in many bacteria. In Xanthomonas campestris pv. campestris 8004, a putative protein encoded by the open reading frame designated as XC1430 shows 42% amino acid similarity with the Zur of Escherichia coli. An XC1430-disrupted mutant 1430nk was constructed by homologous suicide plasmid integration. 1430nk failed to grow in rich medium supplemented with Zn2+ at a concentration of 400 μM and in nonrich medium supplemented with Zn2+ at a concentration of 110 μM, whereas the wild-type strain grew well in the same conditions. In rich medium with 400 μM Zn2+, 1430nk accumulated significantly more Zn2+ than the wild-type strain. 1430nk showed a reduction in virulence on the host plant Chinese radish (Raphanus sativus L. var. radiculus Pers.) and produced less extracellular polysaccharide (EPS) than did the wild-type strain in the absence of added zinc. These results revealed that XC1430 is a functional member of the Zur regulator family that controls zinc homeostasis, EPS production, and virulence in X. campestris pv. campestris.

BIOCHEMICAL IDENTIFICATION OF PATOVARS OF THE PATHOGEN OF VASCULAR BACTERIOSIS OF THE CRUCIFEROUS XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS

2020 ◽  
Vol 15 (1) ◽  
pp. 82-88
Author(s):  
Mikhail Kuznetsov ◽  
◽  
Anatoly Scherbakov ◽  
Elena Gorelnikova ◽  
Nadezhda Chervyakova ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Biochemical Identification ◽  
Xanthomonas Campestris Pv Campestris
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