| the reaction of near-isogenic lines of flax to the rust fungus melampsora lini. ii. biochemical studies. | | 1974 | 4207492 |
| changes in the transcription pattern of flax cotyledons after inoculation with flax rust. | the rate of (32)p incorporation into rna fractions of flax cotyledons (linum usitatissimum l. var. bison) was found to increase two- to three-fold by 48h after inoculation with flax rust [melampsora lini (pers.) lev., race no. 3]. this was accompanied by a change in the nucleotide composition of the newly transcribed sodium chloride-soluble rna fraction. a comparison of the nucleotide composition of the rna synthesized in the host-parasite complex at different stages of development indicated the ... | 1971 | 5126907 |
| lipids of rust fungi. i. lipid metabolism of germinating flax rust uredospores. | | 1967 | 6048378 |
| the l6 gene for flax rust resistance is related to the arabidopsis bacterial resistance gene rps2 and the tobacco viral resistance gene n. | the l6 rust resistance gene from flax was cloned after tagging with the maize transposable element activator. the gene is predicted to encode two products of 1294 and 705 amino acids that result from alternatively spliced transcripts. the longer product is similar to the products of two other plant disease resistance genes, the tobacco mosaic virus resistance gene n of tobacco and the bacterial resistance gene rps2 of arabidopsis. the similarity involves the presence of a nucleotide (atp/gtp) bi ... | 1995 | 7549479 |
| isolation of a flax (linum usitatissimum) gene induced during susceptible infection by flax rust (melampsora lini). | in a susceptible infection of flax (linum usitatissimum), the obligate rust pathogen (melampsora lini) can grow in the leaf without triggering the hypersensitive resistance response. the rust establishes specialized structures (haustoria) in plant mesophyll cells and induces changes in plant subcellular organization. subtraction hybridization methods were used to isolate cdna clones of mrnas that have altered expression in infected leaves. most of the cdnas recovered were of fungal origin, but o ... | 1995 | 7655501 |
| heteroduplex molecules formed between allelic sequences cause nonparental rapd bands. | primers (10-mers) of random sequence were used to amplify rapd bands from genomic dna of an f1 strain of flax rust (melampsora lini) and its two parent strains. one primer out of 160 tested was unusual in that it amplified a product from f1 dna that was not amplified from either parental dnas. the same primer also generated two rapd bands that segregated as codominant alleles amongst f2 progeny. the nonparental band was only generated from dnas of f2 individuals that were heterozygous for these ... | 1994 | 8202363 |
| nucleotide sequence relationships of double-stranded rnas in flax rust, melampsora lini. | flax rust, melampsora lini strain sp6, contains 11 double-stranded (ds) rna molecules with a total length of about 25 kbp. the dsrnas are inherited in three genetic units: the l unit comprising a single 5.2 kbp dsrna and contained within a 40-nm virus-like particle, and the a and b units each consisting of five dsrnas (a1-a5, and b1-b5) ranging in size from 1.2 to 2.7 kbp. this paper reports the isolation of a cdna library representing 10 of the 11 dsrnas. by nucleic-acid hybridization technique ... | 1993 | 8299159 |
| inactivation of the flax rust resistance gene m associated with loss of a repeated unit within the leucine-rich repeat coding region. | the m rust resistance gene from flax was cloned after two separate approaches, an analysis of spontaneous m mutants with an l6 gene-derived dna probe and tagging with the maize transposon activator, independently identified the same gene. the gene encodes a protein of the nucleotide binding site leucine-rich repeat class and is related (86% nucleotide identity) to the unlinked l6 rust resistance gene. in contrast to the l locus, which contains a single gene with multiple alleles, approximately 1 ... | 1997 | 9144966 |
| fungal avirulence genes: structure and possible functions. | avirulence (avr) genes exist in many fungi that share a gene-for-gene relationship with their host plant. they represent unique genetic determinants that prevent fungi from causing disease on plants that possess matching resistance (r) genes. interaction between elicitors (primary or secondary products of avr genes) and host receptors in resistant plants causes induction of various defense responses often involving a hypersensitive response. avr genes have been successfully isolated by reverse g ... | 1998 | 9756710 |
| a flax transposon identified in two spontaneous mutant alleles of the l6 rust resistance gene. | two spontaneous mutant alleles of the l6 flax rust resistance gene, 16-x3a and 16-x117, contain the same transposable element designated dlute (defective linum usitatissimum transposable element). the element is 314 bp long, 70% at-rich and, because it contains no extended open reading frame, is probably non-autonomous. it has 14 bp imperfect terminal inverted repeats related to those in the ac family of plant transposons and, like ac, causes 8 bp target site duplications upon insertion. multipl ... | 1998 | 9881156 |
| identification of regions in alleles of the flax rust resistance gene l that determine differences in gene-for-gene specificity. | thirteen alleles (l, l1 to l11, and lh) from the flax l locus, which encode toll/interleukin-1 receptor homology-nucleotide binding site-leucine-rich repeat (tir-nbs-lrr) rust resistance proteins, were sequenced and compared to provide insight into their evolution and into the determinants of gene-for-gene resistance specificity. the predicted l6 and l11 proteins differ solely in the lrr region, whereas l6 and l7 differ solely in the tir region. thus, specificity differences between alleles can ... | 1999 | 10072407 |
| analysis of alternative transcripts of the flax l6 rust resistance gene. | the l6 rust resistance gene from flax generates at least four transcript classes by alternative splicing of the third intron. the most abundant transcript class encodes a resistance protein containing domains that include nucleotide binding site motifs and a leucine-rich repeat region (nbs-lrr). the remaining three transcript classes encode truncated products which lack most of the c-terminal part of the protein containing the leucine-rich region (lrr). the four transcript classes occur in all p ... | 1999 | 10097386 |
| regions outside of the leucine-rich repeats of flax rust resistance proteins play a role in specificity determination. | multiple alleles controlling different gene-for-gene flax rust resistance specificities occur at the l locus of flax. at least three distinct regions can be recognized in the predicted protein products: the toll/interleukin-1 receptor homology (tir) region, a nucleotide binding site (nbs) region, and a leucine-rich repeat (lrr) region. replacement of the tir-encoding region of the l6 allele with the corresponding regions of l2 or lh by recombination changed the specificity of the allele from l6 ... | 2000 | 10948256 |
| [plants and pathogenic agents, a refined and dangerous relationship: the example of fungi]. | plant-fungus interactions are highly diverse, either being beneficial to the host plant such as those leading to mycorhizal symbiosis, or very detrimental when leading to severe diseases. since the beginning of agriculture, improvement of plant resistance to pathogens has remained a major challenge. breeding for resistance, first conducted empirically in the past centuries, was then performed on a more theoretical basis after the statement of heredity laws by mendel at the end of the xixth centu ... | 2001 | 11570277 |
| advances in plant health management in the twentieth century. | plant health management is the science and practice of understanding and overcoming the succession of biotic and abiotic factors that limit plants from achieving their full genetic potential as crops, ornamentals, timber trees, or other uses. although practiced as long as agriculture itself, as a science-based concept, plant heath management is even younger than integrated pest management (ipm), and includes and builds upon but is not a replacement for ipm. probably the greatest collection of su ... | 2000 | 11701838 |
| a plant gene up-regulated at rust infection sites. | expression of the fis1 gene from flax (linum usitatissimum) is induced by a compatible rust (melampsora lini) infection. infection of transgenic plants containing a beta-glucuronidase (gus) reporter gene under the control of the fis1 promoter showed that induction is highly localized to those leaf mesophyll cells within and immediately surrounding rust infection sites. the level of induction reflects the extent of fungal growth. in a strong resistance reaction, such as the hypersensitive fleck m ... | 2002 | 12011348 |
| local adaptation in the linum marginale-melampsora lini host-pathogen interaction. | the potential for local adaptation between pathogens and their hosts has generated strong theoretical and empirical interest with evidence both for and against local adaptation reported for a range of systems. we use the linum marginale-melampsora lini plant-pathogen system and a hierarchical spatial structure to investigate patterns of local adaptation within a metapopulation characterised by epidemic dynamics and frequent extinction of pathogen populations. based on large sample sizes and comp ... | 2002 | 12206236 |
| [specific molecular markers of the rust resistance gene m4 in flax]. | flax (linum usitatissimum l.) is an important fiber and oil-producing crop. flax rust, caused by melampsora lini ehrenb. lev., occurs worldwide and can cause severe losses in seed yield and fiber quality. in order to identify molecular markers linked to the flax rust resistant gene m4, rapd analysis of nm4, a near-isogenic line containing the m4 gene, and the recurrent parent bison was carried out with 540 decamer primers. the primer opa18 could stably amplify a specific fragment, opa18(432), in ... | 2002 | 12561479 |
| evolution of virulence in a plant host-pathogen metapopulation. | in a wild plant-pathogen system, host resistance and pathogen virulence varied markedly among local populations. broadly virulent pathogens occurred more frequently in highly resistant host populations, whereas avirulent pathogens dominated susceptible populations. experimental inoculations indicated a negative trade-off between spore production and virulence. the nonrandom spatial distribution of pathogens, maintained through time despite high pathogen mobility, implies that selection favors vi ... | 2003 | 12637745 |
| production of aerial mycelium and uredospores by melampsora lini (pers.) lev. on flax leaves in tissue culture. | | 1957 | 13472507 |
| enzymes of the glyoxylate cycle in germinating uredospores of melampsora lini (pers.) lev. | | 1961 | 13701559 |
| utilization of labelled substrates by the mycelium and uredospores of flax rust. | | 1959 | 13839887 |
| enzymatic hydration of cis-9, 10-epoxyoctadecanoic acid by cell-free extracts of germinating flax rust uredospores. | | 1963 | 13953155 |
| tobacco transgenic for the flax rust resistance gene l expresses allele-specific activation of defense responses. | tobacco was transformed with three different alleles (l2, l6, and l10) of the flax rust resistance gene l, a member of the toll interleukin-1 receptor, nucleotide-binding site, leucine-rich repeat (tir-nbs-lrr) class of plant disease resistance genes. l6 transgenics had a stunted phenotype, expressed several defense response genes constitutively, and had increased resistance to the fungus cercospora nicotianae and the oomycete phytophthora parasitica pv. nicotianae. l2 and l10 transgenics, with ... | 2004 | 14964536 |
| the melampsora lini avrl567 avirulence genes are expressed in haustoria and their products are recognized inside plant cells. | the linum usitatissimum (flax) l gene alleles, which encode nucleotide binding site-leu rich repeat class intracellular receptor proteins, confer resistance against the melampsora lini (flax rust) fungus. at least 11 different l resistance specificities are known, and the corresponding avirulence genes in m. lini map to eight independent loci, some of which are complex and encode multiple specificities. we identified an m. lini cdna marker that cosegregates in an f2 rust family with a complex lo ... | 2004 | 14973158 |
| advances in the molecular genetic analysis of the flax-flax rust interaction. | the l6 and m rust-resistance genes, representing two of the five rust-resistance gene loci in flax (linum usitatissimum), have been cloned. the molecular data are fully consistent with earlier genetic data: the l locus is a single gene with multiple alleles expressing different rust resistance specificities, and the m locus is complex, containing an array of about 15 similar genes. thus, while l6 and m resistance genes have 86% nucleotide identity, their locus structure is very different. these ... | 1997 | 15012524 |
| the gene product specified by a double stranded rna in the flax rust (melampsora lini) is expressed during rust growth. | strain sp6 of the flax rust (melampsora lini) contains 11 double-stranded rnas (dsrnas) of unknown function. a large open-reading frame (b3orf1 in dsrna b3 encodes a polypeptide of 614 amino acids, and using an antiserum raised against the b3orf1-glutathione s-transferase fusion protein prepared from a bacterial expression system, we have detected the presence of a 67 kda polypeptide in rust urediospores. this polypeptide, identical in size to that of the predicted translation product of b3orf1 ... | 2004 | 15550768 |
| evolutionary relationships among beta-tubulin gene sequences of basidiomycetous fungi. | 36 fungal beta-tubulin sequences were analysed to study the evolution of this gene and the phylogeny of basidiomycetes. the analysis comprises a representative selection of all major lineages of basidiomycetous fungi and some selected ascomycetes for comparison. intron positions vary between the different lineages, but seem to be conserved in the hymenomycetes and ustilaginomycetes. the most conserved regions seem to be highly susceptible for introns. splicing and branching sites of the introns ... | 2004 | 15587059 |
| autoactive alleles of the flax l6 rust resistance gene induce non-race-specific rust resistance associated with the hypersensitive response. | l6 is a nucleotide binding site-leucine rich repeat (nbs-lrr) gene that confers race-specific resistance in flax (linum usitatissimum) to strains of flax rust (melampsora lini) that carry avirulence alleles of the avrl567 gene but not to rust strains that carry only the virulence allele. several mutant and recombinant forms of l6 were made that altered either the methionine-histidine-aspartate (mhd) motif conserved in the nbs domain of resistance proteins or exchanged the short domain c-terminal ... | 2005 | 15986927 |
| a rust-inducible gene from flax (fis1) is involved in proline catabolism. | a gene fis1 from flax (linum usitatissimum), which is induced in mesophyll cells at the site of rust (melampsora lini) infection, is also expressed in vascular tissue, particularly in floral structures of healthy plants. this paper reports that the promoter controlling this expression is contained within 282 bp 5' to the coding region and that fis1 gene induction is specifically by the rust pathogen and not by other fungal pathogens or by wounding. the fis1 gene has 73% homology with an arabidop ... | 2006 | 16079997 |
| haustorially expressed secreted proteins from flax rust are highly enriched for avirulence elicitors. | rust fungi, obligate biotrophs that cause disease and yield losses in crops such as cereals and soybean (glycine max), obtain nutrients from the host through haustoria, which are specialized structures that develop within host cells. resistance of flax (linum usitatissimum) to flax rust (melampsora lini) involves the induction of a hypersensitive cell death response at haustoria formation sites, governed by gene-for-gene recognition between host resistance and pathogen avirulence genes. we ident ... | 2006 | 16326930 |
| changes in the ribonuclease activity of flax cotyledons following inoculation with flax rust. | there was a significant increase in the ribonuclease activity of both resistant (bombay) and susceptible (bison) varieties of flax (linum usitatissimum l.) 3 to 4 days after inoculation with flax rust (melampsora lini [pers.] lev., race no. 3). a second and much greater increase in the activity of this enzyme occurred only in the susceptible host at later stages of disease development. while a similar increase in ribonuclease level was also caused by mechanical injury, evidence is presented show ... | 1972 | 16658137 |
| changes in two ribonuclease isozymes during rust infection of flax cotyledons. | a ribonuclease fraction previously purified from flax by gel filtration was further resolved into two components by hydroxyl apatite chromatography. these were homogeneous with respect to electrophoresis and isoelectric focusing. both enzymes are of rnase i type but differ in substrate specificity, kinetic properties, ph response, and isoelectric point.the two rnase isozymes show consistent properties when extracted from variety bison (susceptible) or variety bombay (resistant) with or without i ... | 1982 | 16662159 |
| direct protein interaction underlies gene-for-gene specificity and coevolution of the flax resistance genes and flax rust avirulence genes. | plant resistance proteins (r proteins) recognize corresponding pathogen avirulence (avr) proteins either indirectly through detection of changes in their host protein targets or through direct r-avr protein interaction. although indirect recognition imposes selection against avr effector function, pathogen effector molecules recognized through direct interaction may overcome resistance through sequence diversification rather than loss of function. here we show that the flax rust fungus avrl567 g ... | 2006 | 16731621 |
| soil calcium and plant disease in serpentine ecosystems: a test of the pathogen refuge hypothesis. | ecologists have long sought mechanistic explanations for the patterns of plant distribution and endemism associated with serpentine soils. we conducted the first empirical test of the serpentine pathogen refuge hypothesis, which posits that the low levels of calcium found in serpentine soils provide associated plants with a refuge from attack by pathogens. we measured the range of soil calcium concentrations experienced by 16 wild population of california dwarf flax (hesperolinon californicum) a ... | 2007 | 17024377 |
| the use of co2+ for crystallization and structure determination, using a conventional monochromatic x-ray source, of flax rust avirulence protein. | metal-binding sites are ubiquitous in proteins and can be readily utilized for phasing. it is shown that a protein crystal structure can be solved using single-wavelength anomalous diffraction based on the anomalous signal of a cobalt ion measured on a conventional monochromatic x-ray source. the unique absorption edge of cobalt (1.61 a) is compatible with the cu k alpha wavelength (1.54 a) commonly available in macromolecular crystallography laboratories. this approach was applied to the determ ... | 2007 | 17329816 |
| flax rust resistance gene specificity is based on direct resistance-avirulence protein interactions. | genetic studies of the flax-flax rust interaction led to the formulation of the gene-for-gene hypothesis and identified resistance genes (r) in the host plant and pathogenicity genes, including avirulence (avr) and inhibitor of avirulence genes (i), in the rust pathogen. r genes have now been cloned from four of the five loci in flax and all encode proteins of the toll, interleukin-1 receptor, r gene-nucleotide binding site-leucine-rich repeat (tir-nbs-lrr) class. avr genes have been cloned from ... | 2007 | 17430087 |
| purification of the m flax-rust resistance protein expressed in pichia pastoris. | the m flax-rust resistance (r) gene is predicted to encode a 150-kda protein of the toll-interleukin-like receptor-nucleotide binding site-leucine rich repeat (tir-nbs-lrr) class of plant disease resistance proteins and provides resistance against the melampsora lini (flax rust) fungus carrying the avrm avirulence gene. the extremely low level of this class of r proteins found in plant tissue has precluded their biochemical and structural analysis, and the study of these proteins has been largel ... | 2007 | 17461785 |
| the m flax rust resistance pre-mrna is alternatively spliced and contains a complex upstream untranslated region. | alternative splicing is an important step in controlling gene expression and has been shown to occur for a number of plant disease resistance (r) genes. the specific biological role of alternatively spliced transcripts from most r genes is unknown, yet in two cases it is clear that functional disease resistance cannot be activated without them. we report 12 splice isoforms of the m flax rust resistance gene, a tir-nbs-lrr class of r gene. collectively, these isoforms are predicted to encode at l ... | 2007 | 17534592 |
| evolutionary diversification through hybridization in a wild host-pathogen interaction. | coevolutionary outcomes between interacting species are predicted to vary across landscapes, as environmental conditions, gene flow, and the strength of selection vary among populations. using a combination of molecular, experimental, and field approaches, we describe how broad-scale patterns of environmental heterogeneity, genetic divergence, and regional adaptation have the potential to influence coevolutionary processes in the linum marginale-melampsora lini plant-pathogen interaction. we sho ... | 2007 | 17598744 |
| clinal resistance structure and pathogen local adaptation in a serpentine flax-flax rust interaction. | because disease resistance is a hallmark signature of pathogen-mediated selection pressure on hosts, studies of resistance structure (the spatial distribution of disease resistance genes among conspecific host populations) can provide valuable insights into the influence of pathogens on host evolution and spatial variation in the magnitude of their effects. to date few studies of wild plant-pathogen interactions have characterized resistance structure by sampling across the host's biogeographic ... | 2007 | 17683425 |
| the role of secreted proteins in diseases of plants caused by rust, powdery mildew and smut fungi. | five unrelated avirulence (avr) gene families have been cloned from flax rust and barley powdery mildew, fungal pathogens that make close contact with living host plant cells using specialized feeding structures called haustoria. transgenic expression studies indicate avr proteins are recognized by disease resistance (r) proteins within host cells, which suggests that avr proteins are transported via an as yet unidentified route from the fungus to the host during infection. recognition of flax r ... | 2007 | 17698407 |
| relation of antigens of melampsora lini and linum usitatissimum to resistance and susceptibility. | a specific antigen was found in each of four races of melampsora lini and four rust-differentiating varieties of linum usitatissimum. avirulence and virulence were related to resistance and susceptibility through the specific rust antigens. a race was virulent to varieties containing its specific rust antigen as a minor constituent, and avirulent to varieties lacking that antigen. no such correlation was found with flax antigens. | 1960 | 17732689 |
| mutations in flax rust induced by ultraviolet radiation. | | 1956 | 17747204 |
| multiple mating-type specificities in the flax rust melampsora lini. | the results of selfing and intercrossing two strains of the flax rust fungus melampsora lini indicate that this species does not possess a simple(+) and(-) mating system. instead, the data are consistent with the assumption that the genetic control of mating type in melampsora lini is similar to that in the mushroom schizophyllum commune, in which mating type is determined by two factors, each of which is controlled by two linked loci. | 1980 | 17831369 |
| crystal structures of flax rust avirulence proteins avrl567-a and -d reveal details of the structural basis for flax disease resistance specificity. | the gene-for-gene mechanism of plant disease resistance involves direct or indirect recognition of pathogen avirulence (avr) proteins by plant resistance (r) proteins. flax rust (melampsora lini) avrl567 avirulence proteins and the corresponding flax (linum usitatissimum) l5, l6, and l7 resistance proteins interact directly. we determined the three-dimensional structures of two members of the avrl567 family, avrl567-a and avrl567-d, at 1.4- and 2.3-a resolution, respectively. the structures of b ... | 2007 | 17873095 |
| stage-specific gene expression during urediniospore germination in puccinia striiformis f. sp tritici. | puccinia striiformis f. sp. tritici is an obligate biotrophic pathogen that causes leaf stripe rust on wheat. although it is critical to understand molecular mechanisms of pathogenesis in the wheat stripe rust fungus for developing novel disease management strategies, little is known about its genome and gene functions due to difficulties in molecular studies with this important pathogen. to identify genes expressed during early infection stages, in this study we constructed a cdna library with ... | 2008 | 18447959 |
| population structure and diversity in sexual and asexual populations of the pathogenic fungus melampsora lini. | many pathogens undergo both sexual and asexual reproduction to varying degrees, yet the ecological, genetic and evolutionary consequences of different reproductive strategies remain poorly understood. here we investigate the population genetic structure of wild populations of the plant pathogen melampsora lini on its host linum marginale, using amplified fragment length polymorphism (aflp) markers, two genes underlying pathogen virulence, and phenotypic variation in virulence. in australia, m. l ... | 2008 | 18573166 |
| positive selection in avrp4 avirulence gene homologues across the genus melampsora. | pathogen genes involved in interactions with their plant hosts are expected to evolve under positive darwinian selection or balancing selection. in this study a single copy avirulence gene, avrp4, in the plant pathogen melampsora lini, was used to investigate the evolution of such a gene across species. partial translation elongation factor 1-alpha sequences were obtained to establish phylogenetic relationships among the melampsora species. we amplified avrp4 homologues from species pathogenic o ... | 2009 | 19457888 |
| diversity and evolution of effector loci in natural populations of the plant pathogen melampsora lini. | genetic variation for pathogen infectivity is an important driver of disease incidence and prevalence in both natural and managed systems. here, we use the interaction between the rust pathogen, melampsora lini, and two host plants, linum marginale and linum usitatissimum, to examine how host-pathogen interactions influence the maintenance of polymorphism in genes underlying pathogen virulence. extensive sequence variation at two effector loci (avrp123, avrp4) was found in m. lini isolates colle ... | 2009 | 19633228 |
| edaphic quality and plant-pathogen interactions: effects of soil calcium on fungal infection of a serpentine flax. | spatial variation in the frequency and outcome of interspecific interactions is thought to play a central role in shaping geographic patterns of biodiversity. previous empirical studies and modeling exercises suggest that negative species interactions should occur with greater frequency and intensity in high-quality/low-stress environments. i tested this hypothesis through a four-year epidemiological study of interactions between the plant hesperolinon californicum and the pathogenic rust fungus ... | 2009 | 19694134 |
| fungal effector proteins: past, present and future. | the pioneering research of harold flor on flax and the flax rust fungus culminated in his gene-for-gene hypothesis. it took nearly 50 years before the first fungal avirulence (avr) gene in support of his hypothesis was cloned. initially, fungal avr genes were identified by reverse genetics and map-based cloning from model organisms, but, currently, the availability of many sequenced fungal genomes allows their cloning from additional fungi by a combination of comparative and functional genomics. ... | 2009 | 19849781 |
| transformation of the flax rust fungus, melampsora lini: selection via silencing of an avirulence gene. | rust fungi cause devastating diseases on many important food crops, with a damaging stem rust epidemic currently affecting wheat production in africa and the middle east. these parasitic fungi propagate exclusively on plants, precluding the use of many biotechnological tools available for other culturable fungi. in particular the lack of a stable transformation system has been an impediment to the genetic manipulation required for molecular analysis of rust pathogenicity. we have developed an ag ... | 2010 | 19874543 |
| the avrm effector from flax rust has a structured c-terminal domain and interacts directly with the m resistance protein. | in plant immunity, recognition of pathogen effectors by plant resistance proteins leads to the activation of plant defenses and a localized cell death response. the avrm effector from flax rust is a small secreted protein that is recognized by the m resistance protein in flax. here, we investigate the mechanism of m-avrm recognition and show that these two proteins directly interact in a yeast two-hybrid assay, and that this interaction correlates with the recognition specificity observed for ea ... | 2010 | 19958138 |
| relationships between rust resistance genes at the m locus in flax. | genes at the m locus in flax (linum usitatissimum) that confer resistance to flax rust (melampsora lini) occur in complex haplotypes containing up to 15 related genes or gene fragments. we have cloned two additional functional resistance genes at this locus, m1 and m3, by transposon tagging and candidate gene approaches, and investigated the genetic relationships between four genes (m, m1, m3 and m4) by recombination analysis. m1 and m3, like m, are members of the nucleotide binding site, leucin ... | 2010 | 20078773 |
| further analysis of gene-for-gene disease resistance specificity in flax. | summary the flax rust resistance gene l, a nucleotide binding site, leucine-rich repeat (nbs-lrr) class of plant resistance gene, has 12 characterized alleles with different gene-for-gene resistance specificities. here the specificities of presumptive l1, l5, l8 and l11 genomic clones are confirmed by transgenic expression. l6 and l11 differ by 33 amino acids, 32 in the lrr region and one in the c-terminal non-lrr region, and recognize unrelated avirulence proteins, avrl567 and avrl11, respectiv ... | 2007 | 20507482 |
| rust of flax and linseed caused by melampsora lini. | summary: melampsora lini, while of economic importance as the causal agent of rust disease of flax and linseed, has for several decades been the 'model' rust species with respect to genetic studies of avirulence/virulence. studies by harold flor demonstrated that single pairs of allelic genes determine the avirulence/virulence phenotype on host lines with particular resistance genes and led him to propose his famous 'gene-for-gene' hypothesis. flor's inheritance studies, together with those subs ... | 2007 | 20507505 |
| internalization of flax rust avirulence proteins into flax and tobacco cells can occur in the absence of the pathogen. | translocation of pathogen effector proteins into the host cell cytoplasm is a key determinant for the pathogenicity of many bacterial and oomycete plant pathogens. a number of secreted fungal avirulence (avr) proteins are also inferred to be delivered into host cells, based on their intracellular recognition by host resistance proteins, including those of flax rust (melampsora lini). here, we show by immunolocalization that the flax rust avrm protein is secreted from haustoria during infection a ... | 2010 | 20525849 |
| lipid binding activities of flax rust avrm and avrl567 effectors. | effectors are pathogen-encoded proteins that are thought to facilitate infection by manipulation of host cells. evidence showing that the effectors of some eukaryotic plant pathogens are able to interact directly with cytoplasmic host proteins indicates that translocation of these proteins into host cells is an important part of infection. recently, we showed that the flax rust effectors avrm and avrl567 are able to internalize into plant cells in the absence of the pathogen. further, n-terminal ... | 2010 | 20855950 |
| partial resistance in the linum-melampsora host-pathogen system: does partial resistance make the red queen run slower? | five levels of disease expression were scored in a cross-inoculation study of 120 host and 60 pathogen lines of wild flax linum marginale and its rust fungus melampsora lini sampled from six natural populations. patterns of partial resistance showed clear evidence of gene-for-gene interactions, with particular levels of partial resistance occurring in specific host-pathogen combinations. sympatric and putatively more highly coevolved host-pathogen combinations had a lower frequency of partial re ... | 2010 | 21029078 |
| co-evolutionary interactions between host resistance and pathogen effector genes in flax rust disease. | plant-pathogen co-evolutionary selection processes are continuous, complex and occur across many spatial and temporal scales. comprehensive studies of the flax-flax rust pathosystem have led to the postulation of the gene-for-gene model, a genetic paradigm describing recognition events between host disease resistance proteins and pathogen effector proteins. the identification of directly interacting fungal effector proteins and plant disease resistance proteins in this pathosystem has facilitate ... | 2010 | 21118351 |
| spatial variation in disease resistance: from molecules to metapopulations. | variation in disease resistance is a widespread phenomenon in wild plant-pathogen associations. here, we review current literature on natural plant-pathogen associations to determine how diversity in disease resistance is distributed at different hierarchical levels - within host individuals, within host populations, among host populations at the metapopulation scale and at larger regional scales.we find diversity in resistance across all spatial scales examined. furthermore, variability seems t ... | 2011 | 21243068 |
| structural and functional analysis of a plant resistance protein tir domain reveals interfaces for self-association, signaling, and autoregulation. | the toll/interleukin-1 receptor (tir) domain occurs in animal and plant immune receptors. in the animal toll-like receptors, homodimerization of the intracellular tir domain is required for initiation of signaling cascades leading to innate immunity. by contrast, the role of the tir domain in cytoplasmic nucleotide-binding/leucine-rich repeat (nb-lrr) plant immune resistance proteins is poorly understood. l6 is a tir-nb-lrr resistance protein from flax (linum usitatissimum) that confers resistan ... | 2011 | 21402359 |
| an autoactive mutant of the m flax rust resistance protein has a preference for binding atp, while wild-type m protein has a preference for binding adp. | resistance (r) proteins are key regulators of the plant innate immune system and are capable of pathogen detection and activation of the hypersensitive cell death immune response. to understand the molecular mechanism of r protein activation we undertook a phenotypic and biochemical study of the flax nb-arc-lrr protein, m. using agrobacterium -mediated transient expression in flax cotyledons, site-directed mutations of key residues within the p-loop, kinase-2 and mhd motifs within the nb-arc dom ... | 2011 | 21539434 |
| molecular characterization of beta-tubulin from phakopsora pachyrhizi, the causal agent of asian soybean rust. | β-tubulins are structural components of microtubules and the targets of benzimidazole fungicides used to control many diseases of agricultural importance. intron polymorphisms in the intron-rich genes of these proteins have been used in phylogeographic investigations of phytopathogenic fungi. in this work, we sequenced 2764 nucleotides of the β-tubulin gene (pp tubb) in samples of phakopsora pachyrhizi collected from seven soybean fields in brazil. pp tubb contained an open reading frame of 1341 ... | 2010 | 21637494 |
| recognition events and host-pathogen co-evolution in gene-for-gene resistance to flax rust. | the outcome of infection of individual plants by pathogenic organisms is governed by complex interactions between the host and pathogen. these interactions are the result of long-term co-evolutionary processes involving selection and counterselection between plants and their pathogens. these processes are ongoing, and occur at many spatio-temporal scales, including genes and gene products, cellular interactions within host individuals, and the dynamics of host and pathogen populations. however, ... | 2009 | 21760756 |
| 454-pyrosequencing of coffea arabica leaves infected by the rust fungus hemileia vastatrix reveals in planta-expressed pathogen-secreted proteins and plant functions in a late compatible plant-rust interaction. | coffee (coffea arabica l.), one of the key export and cash crops in tropical and subtropical countries, suffers severe losses from the rust fungus hemileia vastatrix. the transcriptome of h. vastatrix was analysed during a compatible interaction with coffee to obtain an exhaustive repertoire of the genes expressed during infection and to identify potential effector genes. large-scale sequencing (454-gs-flex titanium) of mixed coffee and rust cdnas obtained from 21-day rust-infected leaves genera ... | 2011 | 21726390 |
| n-terminal motifs in some plant disease resistance proteins function in membrane attachment and contribute to disease resistance. | to investigate the role of n-terminal domains of plant disease resistance proteins in membrane targeting, the n-termini of a number of arabidopsis and flax disease resistance proteins were fused to gfp and the fusion proteins localized in planta using confocal microscopy. the n-termini of the arabidopsis rpp1-wsb and rps5 resistance proteins and the pbs1 protein, which is required for rps5 resistance, targeted gfp to the plasma membrane, and mutation of predicted myristoylation and potential pal ... | 2011 | 22046960 |
| crystallization and x-ray diffraction analysis of the c-terminal domain of the flax rust effector protein avrm. | the flax rust effector avrm is a secreted protein of unknown fold that is recognized by the m resistance protein in flax. in order to investigate the structural basis of the avrm-m interaction and possible virulence-associated functions of avrm, the c-terminal domains of two different avrm variants (avrm-a and avrm) were crystallized. crystals of native avrm-a were obtained using pentaerythritol ethoxylate (15/4 eo/oh) as a precipitant and diffracted x-rays to 2.9 å resolution. selenomethionine- ... | 2011 | 22139177 |
| nonhost resistance of rice to rust pathogens. | rice is atypical in that it is an agricultural cereal that is immune to fungal rust diseases. this report demonstrates that several cereal rust species (puccinia graminis f. sp tritici, p. triticina, p. striiformis, and p. hordei) can infect rice and produce all the infection structures necessary for plant colonization, including specialized feeding cells (haustoria). some rust infection sites are remarkably large and many plant cells are colonized, suggesting that nutrient uptake occurs to supp ... | 2011 | 21899436 |