| pisatin demethylase genes are on dispensable chromosomes while genes for pathogenicity on carrot and ripe tomato are on other chromosomes in nectria haematococca. | studies on the wide-host-range fungus nectria haematococca mp vi have shown a linkage between virulence on pea and five of nine pda genes that encode the ability to detoxify the pea phytoalexin, pisatin. most of the pda genes are on chromosomes of approximately 1.6 megabases (mb) and two of these genes, pda1-2 and pda6-1, have been demonstrated to reside on approximately 1.6-mb chromosomes that can be lost during meiosis. prior studies also have shown that the dispensable chromosome carrying pda ... | 2002 | 12182342 |
| distribution of the pea pathogenicity ( pep) genes in the fungus nectria haematococca mating population vi. | previous studies identified a cluster of six genes that are expressed in the fungus nectria haematococca mating population vi during infection of pea. four of these genes were shown to contribute to pathogenicity on pea and were called pep genes for pea pathogenicity. the cluster is located on a "conditionally dispensable" (cd) chromosome and has features similar to bacterial pathogenicity islands. in this study, the occurrence and location of members of the pep cluster were analyzed in laborato ... | 2002 | 12073092 |
| physical map of a conditionally dispensable chromosome in nectria haematococca mating population vi and location of chromosome breakpoints. | certain isolates of the plant pathogenic fungus nectria haematococca mating population (mp) vi contain a 1.6-mb conditionally dispensable (cd) chromosome carrying the phytoalexin detoxification genes mak1 and pda6-1. this chromosome is structurally unstable during sexual reproduction. as a first step in our analysis of the mechanisms underlying this chromosomal instability, hybridization between overlapping cosmid clones was used to construct a map of the mak1 pda6-1 chromosome. the map consists ... | 2000 | 10880471 |
| visualization of a conditionally dispensable chromosome in the filamentous ascomycete nectria haematococca by fluorescence in situ hybridization. | supernumerary chromosomes, termed "conditionally dispensable" (cd) chromosomes, are known in nectria haematococca. because these cd chromosomes had been revealed solely by pulsed-field gel electrophoresis, their morphological properties were unknown. in this study, we visualized a 1.6-mb cd chromosome of this fungus by three different types of fluorescence in situ hybridization. the cd chromosome at mitotic metaphase was similar in its appearance to the other chromosomes in the genome. heterochr ... | 1999 | 10361031 |
| a cytoplasmic dynein required for mitotic aster formation in vivo. | an astral pulling force helps to elongate the mitotic spindle in the filamentous ascomycete, nectria haematococca. evidence is mounting that dynein is required for the formation of mitotic spindles and asters. obviously, this would be an important mitotic function of dynein, since it would be a prerequisite for astral force to be applied to a spindle pole. missing from the evidence for such a role of dynein in aster formation, however, has been a dynein mutant lacking mitotic asters. to determin ... | 1998 | 9701559 |
| inducing the loss of conditionally dispensable chromosomes in nectria haematococca during vegetative growth. | a procedure for inducing and detecting the loss of conditionally dispensable (cd) chromosomes in filamentous fungi during vegetative growth was developed using nectria haematococca mating population vi as a model. cd chromosomes in two different isolates of n. haematococca were tagged via integrative transformation with a gene conferring resistance to hygromycin b. in each case the transformation vector included chromosome-specific dna in order to direct its homologous recombination with the des ... | 1998 | 9560438 |
| a fungal kinesin required for organelle motility, hyphal growth, and morphogenesis. | a gene (nhkin1) encoding a kinesin was cloned from nectria haematococca genomic dna by polymerase chain reaction amplification, using primers corresponding to conserved regions of known kinesin-encoding genes. sequence analysis showed that nhkin1 belongs to the subfamily of conventional kinesins and is distinct from any of the currently designated kinesin-related protein subfamilies. deletion of nhkin1 by transformation-mediated homologous recombination caused several dramatic phenotypes: a 50% ... | 1998 | 9436993 |
| expression of the pisatin detoxifying genes (pda) of nectria haematococca in vitro and in planta. | the phytopathogenic fungus nectria haematococca detoxifies pisatin, a phytoalexin produced by pea. pisatin demethylating ability (a phenotype called pda) is due to pisatin demethylase (pdm) and the genes encoding this enzyme are called pda. some isolates rapidly acquire a high to moderate rate of pisatin demethylating activity culture in response to pisatin (phenotypes pdash and pdasm), while other isolates only slowly demethylate pisatin (phenotype pdall). here we report that pda-specific rna l ... | 1996 | 8755624 |
| microbial transformations of steroids--x. cytochromes p-450 11 alpha-hydroxylase and c17-c20 lyase and a 1-ene dehydrogenase transform steroids in nectria haematococca. | nectria haematococca contains four enzymes that metabolise exogenous steroids. two of these are microsomal cytochromes p-450 which act sequentially on progesterone producing firstly, by side-chain cleavage, the c19 steroid androstenedione (c17-c20 lyase), and then, in a subsequent set of transformations, 11 alpha-hydroxylated derivatives (11 alpha-hydroxylase). two other conversions occur after side-chain cleavage. unsaturation, in the form of a double bond at c1-c2, is introduced into the a rin ... | 1996 | 8836168 |
| nrs1, a repetitive element linked to pisatin demethylase genes on a dispensable chromosome of nectria haematococca. | we have identified a repetitive dna element in nectria haematococca mating population vi, isolate t-2. this repetitive sequence has been called nrs1. dna hybridization analysis indicates the sequence is found in several isolates of the fungus pathogenic to pisum sativum. a 2,027-bp clone containing the nrs1-2 allele contains a long polya sequence, imperfect rna polymerase iii promoter sequences, multiple inverted repeats, and the potential for extensive secondary structure similar to known rna p ... | 2010 | 8589408 |
| a gene from the fungal plant pathogen nectria haematococca that encodes the phytoalexin-detoxifying enzyme pisatin demethylase defines a new cytochrome p450 family. | the gene pdat9 from the fungus nectria haematococca encodes pisatin demethylase, an enzyme that detoxifies the phytoalexin pisatin, an antimicrobial compound produced by pea in response to infection by this plant pathogen. pdat9 was found to contain an open reading frame (orf) encoding 515 amino acids and four introns of 52-58 nucleotides each within its coding region. the amino acid sequence f-g-a-g-s-r-s-c-i-g, indicative of the "fifth ligand binding site" present in all cytochrome p450s, occu ... | 1994 | 8208242 |
| a new deoxyfusarubin produced by the fungus nectria haematococca. synthesis of the two isomeric deoxyanhydronaphthopyranones from toralactone. | | 1992 | 1468990 |
| autonomously replicating plasmids and chromosome rearrangement during transformation of nectria haematococca. | a previously described, autonomously replicating plasmid was examined for its ability to replicate in the plant pathogenic fungus, nectria haematococca (nh). the plasmid, pfolt4r4, replicates as a linear molecule, contains a subterminal inverted repeat, as well as the repeated hexanucleotide telomere consensus sequence, ttaggg, at both ends, and increases frequency of fungal transformation approximately 100-fold compared to a similar integrative plasmid, phrc. transformation of nh occurs by way ... | 1992 | 1644317 |
| a fungal gene for antibiotic resistance on a dispensable ("b") chromosome. | a family of cytochrome p-450 (pda) genes in the pathogenic fungus nectria haematococca is responsible for the detoxification of the phytoalexin pisatin, an antimicrobial compound produced by garden pea (pisum sativum l.). the pda6 gene was mapped by electrophoretic karyotype analysis to a small meiotically unstable chromosome that is dispensable for normal growth. such traits are typical of b chromosomes. the strains of nectria studied here have no sequences that are homologous to the pda family ... | 1991 | 1763326 |
| f nuclear magnetic resonance analysis of 5-fluorouracil metabolism in four differently pigmented strains of nectria haematococca. | f nuclear magnetic resonance spectroscopy was used to study the metabolism of 5-fluorouracil in four strains of nectria haematococca which displayed similar sensitivities to growth inhibition by this compound but differed in their pigmentation. the major metabolites, 5-fluorouridine and alpha-fluoro-beta-alanine, were excreted into the medium by all four strains. the classical ribofluoronucleotides (5-fluorouridine-5'-monophosphate, -diphosphate, and -triphosphate) and alpha-fluoro-beta-alanine ... | 1991 | 16348609 |
| organelle motility within mitotic asters of the fungus nectria haematococca. | the mitotic asters of the fungus, nectria haematococca, pull on the spindle pole bodies during anaphase b and help to elongate the central spindle. because these asters are invisible in vivo, studies of their functions during mitosis have been limited. invisible asters in other organisms can be studied in vivo because of visible, membranous organelles that are held or transported within them. this is the first report of intra-astral motility of organelles in a fungus, and it lays the foundation ... | 1991 | 1666364 |
| direct experimental evidence for the existence, structural basis and function of astral forces during anaphase b in vivo. | the existence, structural basis and function of astral forces that are active during anaphase b in the fungus, nectria haematococca, were revealed by experiments performed on living cells. when one of the two asters of a mitotic apparatus was damaged, the entire mitotic apparatus migrated rapidly in the direction of the opposing astral forces, showing that the force that accelerated spindle pole body separation in earlier experiments is located in the asters. when a strong solution of the antimi ... | 1991 | 1757488 |
| identification and chromosomal locations of a family of cytochrome p-450 genes for pisatin detoxification in the fungus nectria haematococca. | the ability to detoxify the phytoalexin, pisatin, an antimicrobial compound produced by pea (pisum sativum l.), is one requirement for pathogenicity of the fungus nectria haematococca on this plant. detoxification is mediated by a cytochrome p-450, pisatin demethylase, encoded by any one of six pda genes, which differ with respect to the inducibility and level of pisatin demethylase activity they confer, and which are associated with different levels of virulence on pea. a previously cloned pda ... | 1991 | 2034215 |
| 6-o-demethyl-5-deoxyfusarubin and its anhydro derivative produced by a mutant of the fungus nectria haematococca blocked in fusarubin biosynthesis. | 6-o-demethyl-5-deoxyfursarubin and 6-o-demethyl-5-deoxyanhydrofusarubin have been isolated from the mutant redd169.yely9 of the fungus nectria haematococca blocked in fusarubin biosynthesis. these products were identified on the basis of physico-chemical data by comparison with known substances. | 1991 | 2001980 |
| 19f nuclear magnetic resonance analysis of 5-fluorouracil metabolism in wild-type and 5-fluorouracil-resistant nectria haematococca. | a mutant (fura3) was isolated from the s1 wild-type strain of nectria haematococca on the basis of its resistance to 5-fluorouracil (5fu). this mutant has greatly reduced activity of uracil phosphoribosyltransferase, a pyrimidine salvage enzyme catalyzing the synthesis of ump from uracil. the metabolism of 5fu was examined in both strains by using 19f nuclear magnetic resonance spectroscopy. in the s1 strain, 5fu appears to be metabolized by two pathways operating simultaneously: (i) conversion ... | 1989 | 2604390 |
| role of oxygenases in pisatin biosynthesis and in the fungal degradation of maackiain. | some isolates of the plant pathogen nectria haematococca detoxify the isoflavonoid phytoalexin (-)maackiain by hydroxylation at carbon 6a. precursor feeding studies strongly suggest that the penultimate step in (+)pisatin biosynthesis by pisum sativum is 6a-hydroxylation of (+)maackiain. we have used (18)o labeling to test the involvement of oxygenases in these two reactions. when fungal metabolism of maackiain took place under (18)o(2), the product was labeled with 99% efficiency; no label was ... | 1987 | 16665251 |
| solubilization and reconstitution of pisatin demethylase, a cytochrome p-450 from the pathogenic fungus nectria haematococca. | some isolates of the fungus nectria haematococca berk. and br. can demethylate pisatin, a phytoalexin from pea (pisum sativum l.). pisatin demethylation appears to be necessary for tolerance to pisatin and virulence on pea, and is catalyzed by a microsomal cytochrome p-450. we now report solubilization of this enzyme from n. haematococca microsomes. pisatin demethylase activity was obtained in the high speed supernatant of detergent treated microsomes, if detergent was removed before assay. the ... | 1984 | 16663674 |
| detoxification of the phytoalexin pisatin by a fungal cytochrome p-450. | the fungus nectria haematococca, a pathogen of garden pea (pisum sativum), can demethylate pisatin, an antimicrobial compound synthesized by infected pea tissue. the phenolic product is less toxic than pisatin to many microorganisms. cell extracts catalyzing pisatin demethylation were obtained from n. haematococca, and the properties of the reaction were examined. the enzyme activity was greatest in the high-speed pellet fraction, in which rates up to 20 nmol/min/mg protein were observed. the km ... | 1983 | 6870275 |
| action spectrum of the photoinduced sexual stage in the fungus nectria haematococca berk. and br. var cucurbitae (snyder and hansen) dingley. | an action spectrum was determined for the photoinduced formation of perithecia in a homothallic strain of nectria haematococca berk. and br. var. cucurbitae (snyder and hansen) dingley. dose-response curves for perithecial formation were obtained from 340 to 510 nanometers at 10-nanometer intervals. radiation longer than 510 nanometers was not effective for inducing perithecial formation. the action spectrum indicated peaks of activity near 360, 440, and 480 nanometers with shoulders near 420 an ... | 1972 | 16657931 |
| genetic analysis of dodine resistance in nectria haematococca (syn. hypomyces solani). | | 1970 | 5519659 |
| photoinduced perithecial formation by nectria haematococca on media containing either l-tyrosine; l-phenylalanine; or d-glucose+nano3 as sole carbon and nitrogen sources. | | 1969 | 5344738 |