# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 6355 | 0 | 0.9951 | Regulation of resistance to copper in Xanthomonas axonopodis pv. vesicatoria. Copper-resistant strains of Xanthomonas axonopodis pv. vesicatoria were previously shown to carry plasmid-borne copper resistance genes related to the cop and pco operons of Pseudomonas syringae and Escherichia coli, respectively. However, instead of the two-component (copRS and pcoRS) systems determining copper-inducible expression of the operons in P. syringae and E. coli, a novel open reading frame, copL, was found to be required for copper-inducible expression of the downstream multicopper oxidase copA in X. axonopodis. copL encodes a predicted protein product of 122 amino acids that is rich in histidine and cysteine residues, suggesting a possible direct interaction with copper. Deletions or frameshift mutations within copL, as well as an amino acid substitution generated at the putative start codon of copL, caused a loss of copper-inducible transcriptional activation of copA. A nonpolar insertion of a kanamycin resistance gene in copL resulted in copper sensitivity in the wild-type strain. However, repeated attempts to complement copL mutations in trans failed. Analysis of the genomic sequence databases shows that there are copL homologs upstream of copAB genes in X. axonopodis pv. citri, X. campestris pv. campestris, and Xylella fastidiosa. The cloned promoter area upstream of copA in X. axonopodis pv. vesicatoria did not function in Pseudomonas syringae or in E. coli, nor did the P. syringae cop promoter function in Xanthomonas. However, a transcriptional fusion of the Xanthomonas cop promoter with the Pseudomonas copABCDRS was able to confer resistance to copper in Xanthomonas, showing divergence in the mechanisms of regulation of the resistance to copper in phytopathogenic bacteria. | 2005 | 15691931 |
| 64 | 1 | 0.9951 | Mutational analysis of the Arabidopsis RPS2 disease resistance gene and the corresponding pseudomonas syringae avrRpt2 avirulence gene. Plants have evolved a large number of disease resistance genes that encode proteins containing conserved structural motifs that function to recognize pathogen signals and to initiate defense responses. The Arabidopsis RPS2 gene encodes a protein representative of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of plant resistance proteins. RPS2 specifically recognizes Pseudomonas syringae pv. tomato strains expressing the avrRpt2 gene and initiates defense responses to bacteria carrying avrRpt2, including a hypersensitive cell death response (HR). We present an in planta mutagenesis experiment that resulted in the isolation of a series of rps2 and avrRpt2 alleles that disrupt the RPS2-avrRpt2 gene-for-gene interaction. Seven novel avrRpt2 alleles incapable of eliciting an RPS2-dependent HR all encode proteins with lesions in the C-terminal portion of AvrRpt2 previously shown to be sufficient for RPS2 recognition. Ten novel rps2 alleles were characterized with mutations in the NBS and the LRR. Several of these alleles code for point mutations in motifs that are conserved among NBS-LRR resistance genes, including the third LRR, which suggests the importance of these motifs for resistance gene function. | 2001 | 11204781 |
| 9983 | 2 | 0.9950 | A new drug design strategy: Killing drug resistant bacteria by deactivating their hypothetical genes. Despite that a bacterial genome is complicated by large numbers of horizontally transferred (HT) genes and function unknown hypothetical (FUN) genes, the Genic-Transcriptional-Stop-Signals-Ratio (TSSR) of a genome shows that HT and FUN genes are complementary to all other genes in the genome. When HT or certain FUN genes are omitted from the Escherichia coli K-12 genome, its Genomic-TSSR value becomes totally incomparable to other E. coli strains. The Genic-TSSR correlation tree of a pathogen shows that some FUN genes would form a unique cluster. Removing these genes by site-specific mutation or gene-knockout should lead to the demise of this pathogen. | 2016 | 27901648 |
| 6356 | 3 | 0.9950 | Contribution of chloride channel permease to fluoride resistance in Streptococcus mutans. Genes encoding fluoride transporters have been identified in bacterial and archaeal species. The genome sequence of the cariogenic Streptococcus mutans bacteria suggests the presence of a putative fluoride transporter, which is referred to as a chloride channel permease. Two homologues of this gene (GenBank locus tags SMU_1290c and SMU_1289c) reside in tandem in the genome of S. mutans The aim of this study was to determine whether the chloride channel permeases contribute to fluoride resistance. We constructed SMU_1290c- and SMU_1289c-knockout S. mutans UA159 strains. We also constructed a double-knockout strain lacking both genes. SMU_1290c or SMU_1289c was transformed into a fluoride transporter- disrupted Escherichia coli strain. All bacterial strains were cultured under appropriate conditions with or without sodium fluoride, and fluoride resistance was evaluated. All three gene-knockout S. mutans strains showed lower resistance to sodium fluoride than did the wild-type strain. No significant changes in resistance to other sodium halides were recognized between the wild-type and double-knockout strains. Both SMU_1290c and SMU_1289c transformation rescued fluoride transporter-disrupted E. coli cell from fluoride toxicity. We conclude that the chloride channel permeases contribute to fluoride resistance in S. mutans. | 2016 | 27190286 |
| 369 | 4 | 0.9950 | A gene fusion system using the aminoglycoside 3'-phosphotransferase gene of the kanamycin-resistance transposon Tn903: use in the yeast Kluyveromyces lactis and Saccharomyces cerevisiae. The aminoglycoside 3'-phosphotransferase type I (APHI)-coding gene of the bacterial transposon Tn903 confers resistance to kanamycin on bacteria and resistance to geneticin (G418) on many eukaryotes. We developed an APHI fusion system that can be used in the study of gene expression in these organisms, particularly in yeasts. The first 19 codons of the KmR (APHI) gene can be deleted, and replaced by other genes in a continuous reading frame, without loss of APH activity. Examples of vector constructions are given which are adapted to the yeast Kluyveromyces lactis transformation system. Their derivatives containing the 2 mu origin of replication can also be used in Saccharomyces cerevisiae. | 1988 | 2853096 |
| 548 | 5 | 0.9950 | Mammalian antioxidant protein complements alkylhydroperoxide reductase (ahpC) mutation in Escherichia coli. The MER5 [now called the Aop1 (antioxidant protein 1) gene] was cloned as a transiently expressed gene of murine erythroleukaemia (MEL) cell differentiation and its antisense expression inhibited differentiation of MEL cells. We found that the Aop1 gene shows significant nucleotide sequence similarity to the gene coding for the C22 subunit of Salmonella typhimurium alkylhydroperoxide reductase, which is also found in other bacteria, suggesting it functions as an antioxidant protein. Expression of the Aop1 gene product in E. coli deficient in the C22-subunit gene rescued resistance of the bacteria to alkylhydroperoxide. The human and mouse Aop1 genes are highly conserved, and they mapped to the regions syntenic between mouse and human chromosomes. Sequence comparisons with recently cloned mammalian Aop1 homologues suggest that these genes consist of a family that is responsible for regulation of cellular proliferation, differentiation and antioxidant functions. | 1995 | 7733872 |
| 65 | 6 | 0.9949 | Isolation of phytoalexin-deficient mutants of Arabidopsis thaliana and characterization of their interactions with bacterial pathogens. A genetic approach was used to assess the extent to which a particular plant defense response, phytoalexin biosynthesis, contributes to Arabidopsis thaliana resistance to Pseudomonas syringae pathogens. The A. thaliana phytoalexin, camalexin, accumulated in response to infection by various P. syringae strains. No correlation between pathogen avirulence and camalexin accumulation was observed. A biochemical screen was used to isolate three mutants of A. thaliana ecotype Columbia that were phytoalexin deficient (pad mutants). The mutations pad1, pad2, and pad3 were found to be recessive alleles of three different genes. pad1 and pad2 were mapped to chromosome IV and pad3 was mapped to chromosome III. Infection of pad mutant plants with strains carrying cloned avirulence genes revealed that the pad mutations did not affect the plants' ability to restrict the growth of these strains. This result strongly suggests that in A. thaliana, phytoalexin biosynthesis is not required for resistance to avirulent P. syringae pathogens. Two of the pad mutants displayed enhanced sensitivity to isogenic virulent P. syringae pathogens, suggesting that camalexin may serve to limit the growth of virulent bacteria. | 1994 | 8090752 |
| 61 | 7 | 0.9949 | RPS2 of Arabidopsis thaliana: a leucine-rich repeat class of plant disease resistance genes. Plant disease resistance genes function is highly specific pathogen recognition pathways. PRS2 is a resistance gene of Arabidopsis thaliana that confers resistance against Pseudomonas syringae bacteria that express avirulence gene avrRpt2. RPS2 was isolated by the use of a positional cloning strategy. The derived amino acid sequence of RPS2 contains leucine-rich repeat, membrane-spanning, leucine zipper, and P loop domains. The function of the RPS2 gene product in defense signal transduction is postulated to involve nucleotide triphosphate binding and protein-protein interactions and may also involve the reception of an elicitor produced by the avirulent pathogen. | 1994 | 8091210 |
| 373 | 8 | 0.9949 | The ybiT gene of Erwinia chrysanthemi codes for a putative ABC transporter and is involved in competitiveness against endophytic bacteria during infection. We investigated the role in bacterial infection of a putative ABC transporter, designated ybiT, of Erwinia chrysanthemi AC4150. The deduced sequence of this gene showed amino acid sequence similarity with other putative ABC transporters of gram-negative bacteria, such as Escherichia coli and Pseudomonas aeruginosa, as well as structural similarity with proteins of Streptomyces spp. involved in resistance to macrolide antibiotics. The gene contiguous to ybiT, designated as pab (putative antibiotic biosynthesis) showed sequence similarity with Pseudomonas and Streptomyces genes involved in the biosynthesis of antibiotics. A ybiT mutant (BT117) was constructed by marker exchange. It retained full virulence in potato tubers and chicory leaves, but it showed reduced ability to compete in planta against the wild-type strain or against selected saprophytic bacteria. These results indicate that the ybiT gene plays a role in the in planta fitness of the bacteria. | 2002 | 11916677 |
| 372 | 9 | 0.9949 | A chromosomal locus required for copper resistance, competitive fitness, and cytochrome c biogenesis in Pseudomonas fluorescens. A chromosomal locus required for copper resistance and competitive fitness was cloned from a strain of Pseudomonas fluorescens isolated from copper-contaminated agricultural soil. Sequence analysis of this locus revealed six open reading frames with homology to genes involved in cytochrome c biogenesis in other bacteria, helC, cycJ, cycK, tipB, cycL, and cycH, with the closest similarity being to the aeg-46.5(yej) region of the Escherichia coli chromosome. The proposed functions of these genes in other bacteria include the binding, transport, and coupling of heme to apocytochrome c in the periplasm of these Gram-negative bacteria. Putative heme-binding motifs were present in the predicted products of cycK and cycL, and TipB contained a putative disulfide oxidoreductase active site proposed to maintain the heme-binding site of the apocytochrome in a reduced state for ligation of heme. Tn3-gus mutagenesis showed that expression of the genes was constitutive but enhanced by copper, and confirmed that the genes function both in copper resistance and production of active cytochrome c. However, two mutants in cycH were copper-sensitive and oxidase-positive, suggesting that the functions of these genes, rather than cytochrome c oxidase itself, were required for resistance to copper. | 1996 | 8692990 |
| 44 | 10 | 0.9948 | The ubiquitin pathway is required for innate immunity in Arabidopsis. Plant defences require a multitude of tightly regulated resistance responses. In Arabidopsis, the unique gain-of-function mutant suppressor of npr1-1 constitutive 1 (snc1) carries a point mutation in a Resistance (R)-gene, resulting in constitutive activation of defence responses without interaction with pathogens. This has allowed us to identify various downstream signalling components essential in multiple defence pathways. One mutant that suppresses snc1-mediated constitutive resistance is modifier of snc1 5 (mos5), which carries a 15-bp deletion in UBA1, one of two ubiquitin-activating enzyme genes in Arabidopsis. A mutation in UBA2 does not suppress snc1, suggesting that these two genes are not equally required in Arabidopsis disease resistance. On the other hand, a mos5 uba2 double mutant is lethal, implying partial redundancy of the two homologues. Apart from affecting snc1-mediated resistance, mos5 also exhibits enhanced disease susceptibility to a virulent pathogen and is impaired in response to infection with avirulent bacteria carrying the protease elicitor AvrRpt2. The mos5 mutation in the C-terminus of UBA1 might affect binding affinity of the downstream ubiquitin-conjugating enzymes, thus perturbing ubiquitination of target proteins. Furthermore, SGT1b and RAR1, which are necessary for resistance conferred by the SNC1-related R-genes RPP4 and RPP5, are dispensable in snc1-mediated resistance. Our data reveal the definite requirement for the ubiquitination pathway in the activation and downstream signalling of several R-proteins. | 2007 | 17217463 |
| 63 | 11 | 0.9947 | RPS2, an Arabidopsis disease resistance locus specifying recognition of Pseudomonas syringae strains expressing the avirulence gene avrRpt2. A molecular genetic approach was used to identify and characterize plant genes that control bacterial disease resistance in Arabidopsis. A screen for mutants with altered resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) expressing the avirulence gene avrRpt2 resulted in the isolation of four susceptible rps (resistance to P. syringae) mutants. The rps mutants lost resistance specifically to bacterial strains expressing avrRpt2 as they retained resistance to Pst strains expressing the avirulence genes avrB or avrRpm1. Genetic analysis indicated that in each of the four rps mutants, susceptibility was due to a single mutation mapping to the same locus on chromosome 4. Identification of a resistance locus with specificity for a single bacterial avirulence gene suggests that this locus, designated RPS2, controls specific recognition of bacteria expressing the avirulence gene avrRpt2. Ecotype Wü-0, a naturally occurring line that is susceptible to Pst strains expressing avrRpt2, appears to lack a functional allele at RPS2, demonstrating that there is natural variation at the RPS2 locus among wild populations of Arabidopsis. | 1993 | 8400869 |
| 371 | 12 | 0.9947 | Single amino acid substitutions in the enzyme acetolactate synthase confer resistance to the herbicide sulfometuron methyl. Sulfometuron methyl, a sulfonylurea herbicide, blocks growth of bacteria, yeast, and higher plants by inhibition of acetolactate synthase (EC 4.1.3.18), the first common enzyme in the biosynthesis of branched-chain amino acids. Spontaneous mutations that confer increased resistance to the herbicide were obtained in cloned genes for acetolactate synthase from Escherichia coli and Saccharomyces cerevisiae. The DNA sequence of a bacterial mutant gene and a yeast mutant gene revealed single nucleotide differences from their respective wild-type genes. The mutations result in single amino acid substitutions in the structurally homologous aminoterminal regions of the two proteins, but at different positions. The bacterial mutation results in reduced levels of acetolactate synthase activity, reduced sensitivity to sulfometuron methyl, and unaltered resistance to feedback inhibition by valine. The yeast mutation results in unaltered levels of acetolactate synthase activity, greatly reduced sensitivity to sulfometuron methyl, and slightly reduced sensitivity to valine. | 1986 | 16593715 |
| 163 | 13 | 0.9946 | Copper resistance in the cold: Genome analysis and characterisation of a P(IB-1) ATPase in Bizionia argentinensis. Copper homeostasis is a fundamental process in organisms, characterised by unique pathways that have evolved to meet specific needs while preserving core resistance mechanisms. While these systems are well-documented in model bacteria, information on copper resistance in species adapted to cold environments is scarce. This study investigates the potential genes related to copper homeostasis in the genome of Bizionia argentinensis (JUB59-T), a psychrotolerant bacterium isolated from Antarctic seawater. We identified several genes encoding proteins analogous to those crucial for copper homeostasis, including three sequences of copper-transport P1B-type ATPases. One of these, referred to as BaCopA1, was chosen for cloning and expression in Saccharomyces cerevisiae. BaCopA1 was successfully integrated into yeast membranes and subsequently extracted with detergent. The purified BaCopA1 demonstrated the ability to catalyse ATP hydrolysis at low temperatures. Structural models of various BaCopA1 conformations were generated and compared with mesophilic and thermophilic homologous structures. The significant conservation of critical residues and structural similarity among these proteins suggest a shared reaction mechanism for copper transport. This study is the first to report a psychrotolerant P1B-ATPase that has been expressed and purified in a functional form. | 2024 | 38943264 |
| 62 | 14 | 0.9946 | Different requirements for EDS1 and NDR1 by disease resistance genes define at least two R gene-mediated signaling pathways in Arabidopsis. The Arabidopsis genes EDS1 and NDR1 were shown previously by mutational analysis to encode essential components of race-specific disease resistance. Here, we examined the relative requirements for EDS1 and NDR1 by a broad spectrum of Resistance (R) genes present in three Arabidopsis accessions (Columbia, Landsberg-erecta, and Wassilewskija). We show that there is a strong requirement for EDS1 by a subset of R loci (RPP2, RPP4, RPP5, RPP21, and RPS4), conferring resistance to the biotrophic oomycete Peronospora parasitica, and to Pseudomonas bacteria expressing the avirulence gene avrRps4. The requirement for NDR1 by these EDS1-dependent R loci is either weak or not measurable. Conversely, three NDR1-dependent R loci, RPS2, RPM1, and RPS5, operate independently of EDS1. Another RPP locus, RPP8, exhibits no strong exclusive requirement for EDS1 or NDR1 in isolate-specific resistance to P. parasitica, although resistance is compromised weakly by eds1. Similarly, resistance conditioned by two EDS1-dependent RPP genes, RPP4 and RPP5, is impaired partially by ndr1, implicating a degree of pathway cross-talk. Our results provide compelling evidence for the preferential utilization of either signaling component by particular R genes and thus define at least two disease resistance pathways. The data also suggest that strong dependence on EDS1 or NDR1 is governed by R protein structural type rather than pathogen class. | 1998 | 9707643 |
| 69 | 15 | 0.9946 | Interfering TAL effectors of Xanthomonas oryzae neutralize R-gene-mediated plant disease resistance. Plant pathogenic bacteria of the genus Xanthomonas possess transcription activator-like effectors (TALEs) that activate transcription of disease susceptibility genes in the host, inducing a state of disease. Here we report that some isolates of the rice pathogen Xanthomonas oryzae use truncated versions of TALEs (which we term interfering TALEs, or iTALEs) to overcome disease resistance. In comparison with typical TALEs, iTALEs lack a transcription activation domain but retain nuclear localization motifs and are expressed from genes that were previously considered pseudogenes. We show that the rice gene Xa1, encoding a nucleotide-binding leucine-rich repeat protein, confers resistance against X. oryzae isolates by recognizing multiple TALEs. However, the iTALEs present in many isolates interfere with the otherwise broad-spectrum resistance conferred by Xa1. Our findings illustrate how bacterial effectors that trigger disease resistance in the host can evolve to interfere with the resistance process and, thus, promote disease. | 2016 | 27811915 |
| 448 | 16 | 0.9946 | Gene-for-gene interactions of five cloned avirulence genes from Xanthomonas campestris pv. malvacearum with specific resistance genes in cotton. A total DNA clone bank of a strain of Xanthomonas campestris pv. malvacearum (Xcm) was constructed in the cosmid vector pSa747 and transfected into Escherichia coli. The Xcm strain carries at least nine identifiable avirulence (A) genes. Clones in E. coli were mated individually into a recombination-proficient Xcm isolate carrying no known A genes. Screening was for incompatibility on congenic cotton host lines that differ by single specific resistance (R) genes. Ten different cosmid clones conferring race-specific avirulence were recovered. In most cases, the same A gene clone was recovered independently several times. Using the congenic host lines and the merodiploid transconjugant pathogen strains, five of the A genes were shown to specifically interact, gene-for-gene, with individual R genes in the congenic cotton lines. Some A/R gene interactions appeared qualitatively different from others, suggesting that the physiological mechanism(s) of gene-for-gene specified incompatibility may be unique to the interactive gene pair. All A genes appeared to be chromosomally determined, three were found linked on a single 32-kilobase clone, and the rest were spaced more than 31 kilobases apart. Colinearity of the cosmid inserts with the Xcm recipient (carrying no known A genes) chromosome was demonstrated in two of the three tested. This and other evidence suggests that at least some A genes in bacteria may have the equivalent of virulence (a) alleles. The genetics of race specificity in this phytopathogenic bacterium appeared in all respects to be identical to that found in phytopathogenic fungi. | 1986 | 16593751 |
| 447 | 17 | 0.9945 | The root knot nematode resistance gene Mi from tomato is a member of the leucine zipper, nucleotide binding, leucine-rich repeat family of plant genes. The Mi locus of tomato confers resistance to root knot nematodes. Tomato DNA spanning the locus was isolated as bacterial artificial chromosome clones, and 52 kb of contiguous DNA was sequenced. Three open reading frames were identified with similarity to cloned plant disease resistance genes. Two of them, Mi-1.1 and Mi-1.2, appear to be intact genes; the third is a pseudogene. A 4-kb mRNA hybridizing with these genes is present in tomato roots. Complementation studies using cloned copies of Mi-1.1 and Mi-1.2 indicated that Mi-1.2, but not Mi-1.1, is sufficient to confer resistance to a susceptible tomato line with the progeny of transformants segregating for resistance. The cloned gene most similar to Mi-1.2 is Prf, a tomato gene required for resistance to Pseudomonas syringae. Prf and Mi-1.2 share several structural motifs, including a nucleotide binding site and a leucine-rich repeat region, that are characteristic of a family of plant proteins, including several that are required for resistance against viruses, bacteria, fungi, and now, nematodes. | 1998 | 9707531 |
| 125 | 18 | 0.9945 | ROD1, a novel gene conferring multiple resistance phenotypes in Saccharomyces cerevisiae. Glutathione-dependent detoxification reactions are catalyzed by the enzyme glutathione S-transferase and are important in drug resistance in organisms ranging from bacteria to humans. The yeast Issatchenkia orientalis expresses a glutathione S-transferase (GST) protein that is induced when the GST substrate o-dinitrobenzene (o-DNB) is added to the culture. In this study, we show that overproduction of the I. orientalis GST in Saccharomyces cerevisiae leads to an increase in o-dinitrobenzene resistance in S. cerevisiae cells. To recover genes that influence o-DNB resistance in S. cerevisiae, a high copy plasmid library was screened for loci that elevate o-DNB tolerance. One gene was recovered and designated ROD1 (resistance to o-dinitrobenzene). This locus was found to encode a novel protein with no significant sequence similarity with proteins of known function in the data base. An epitope-tagged version of Rod1p was produced in S. cerevisiae and shown to function properly. Subcellular fractionation experiments indicated that this factor was found in the particulate fraction by differential centrifugation. Overproduction of Rod1p leads to resistance to not only o-DNB but also zinc and calcium. Strains that lack the ROD1 gene are hypersensitive to these same compounds. Rod1p represents a new type of molecule influencing drug tolerance in eukaryotes. | 1996 | 8621680 |
| 178 | 19 | 0.9945 | Molecular basis of bacterial resistance to organomercurial and inorganic mercuric salts. Bacteria mediate resistance to organomercurial and inorganic mercuric salts by metabolic conversion to nontoxic elemental mercury, Hg(0). The genes responsible for mercury resistance are organized in the mer operon, and such operons are often found in plasmids that also bear drug resistance determinants. We have subcloned three of these mer genes, merR, merB, and merA, and have studied their protein products via protein overproduction and purification, and structural and functional characterization. MeR is a metalloregulatory DNA-binding protein that acts as a repressor of both its own and structural gene transcription in the absence of Hg(II); in addition it acts as a positive effector of structural gene transcription when Hg(II) is present. MerB, organomercury lyase, catalyzes the protonolytic fragmentation of organomercurials to the parent hydrocarbon and Hg(II) by an apparent SE2 mechanism. MerA, mercuric ion reductase, is an FAD-containing and redox-active disulfide-containing enzyme with homology to glutathione reductase. It has evolved the unique catalytic capacity to reduce Hg(II) to Hg(0) and thereby complete the detoxification scheme. | 1988 | 3277886 |