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Sample records for rust fungus uromyces

  1. A putative amino acid transporter is specifically expressed in haustoria of the rust fungus Uromyces fabae.

    Science.gov (United States)

    Hahn, M; Neef, U; Struck, C; Göttfert, M; Mendgen, K

    1997-05-01

    A cDNA library constructed from haustoria of the rust fungus Uromyces fabae was screened for clones that are differentially expressed in haustoria. One family of cDNAs (in planta-induced gene 2 [PIG2] was isolated and found to encode a protein with high homologies to fungal amino acid transporters. A cDNA clone containing the complete coding region of PIG2 and the corresponding genomic clone were isolated and sequenced, revealing the presence of 17 introns in the PIG2 gene. Expression of PIG2 mRNA appeared to be restricted to haustoria. With antibodies raised against synthetic peptides, the PIG2-encoded protein was found in membranes fractions of isolated haustoria but not of germinated rust spores. With immunofluorescence microscopy, the putative amino acid transporter was localized to plasma membranes of the haustorial bodies, but not detected in the haustorial neck, haustorial mother cells, or intercellular fungal hyphae growing within infected leaf tissue. These data present for the first time molecular evidence that the rust haustorium plays a special role in the uptake of nutrients from an infected host cell.

  2. The rust fungus Uromyces geranii (DC. Lev. localization and impact on anatomy of the host plant Geranium sanguineum L.

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    Emma Biruliova

    2013-04-01

    Full Text Available The investigations on the rust fungus Uromyces geranii (DC. Lev. influence on the anatomy of the vegetative organs of the host plantGeranium sanguineumL. (Geraniaceae were conducted. The local and endophytic arrangement of U. geraniiin the tissues of the host plant were identified. The tissues hypertrophy and organs deformation in G. sanguineum were revealed as a consequences of the fungus U. geraniiinfluence as well as increment of pericyclic ring sclerenchyma lignification in the stem. While the mature aecia and uredinia on the stem cause the epidermis tears and fill the primary cortex up to the stele.

  3. Characterization of a developmentally regulated amino acid transporter (AAT1p) of the rust fungus Uromyces fabae

    OpenAIRE

    Struck, Christine; Ernst, Michael; Hahn, Matthias

    2002-01-01

    In the rust fungus Uromyces fabae, invasion of the host plant and haustorium formation are accompanied by the activation of many genes (PIGs = in planta induced genes). In addition to the previously described AAT2 (PIG2), AAT1 (PIG27) was found to encode a protein with a high similarity to fungal amino acid permeases. AAT1 transcripts are present in germinated hyphae and throughout the mycelium later in the infection process, but occur at the highest levels in haustoria. Expression of AAT1p i...

  4. Characterization of a developmentally regulated amino acid transporter (AAT1p) of the rust fungus Uromyces fabae.

    Science.gov (United States)

    Struck, Christine; Ernst, Michael; Hahn, Matthias

    2002-01-01

    summary In the rust fungus Uromyces fabae, invasion of the host plant and haustorium formation are accompanied by the activation of many genes (PIGs =in planta induced genes). In addition to the previously described AAT2 (PIG2), AAT1 (PIG27) was found to encode a protein with a high similarity to fungal amino acid permeases. AAT1 transcripts are present in germinated hyphae and throughout the mycelium later in the infection process, but occur at the highest levels in haustoria. Expression of AAT1p in a histidine uptake-defective yeast mutant revealed energy-dependent transport of (14)C-histidine, with a K(M) value of 25.8 microm. In addition, complementation analysis revealed AAT1-dependent transport for lysine. Using Xenopus oocytes as expression system, AAT1p-dependent symport of protons with a broad spectrum of amino acids was observed, with the highest activities obtained with histidine and lysine. These results confirm that in rust fungi, the expression of amino acid transporters is developmentally regulated and occurs preferentially in the parasitic phase of development.

  5. The Plasma Membrane H+-ATPase from the Biotrophic Rust Fungus Uromyces fabae : molecular Characterization of the Gene (PMA1) and Functional Expression of the Enzyme in Yeast

    OpenAIRE

    Struck, Christine; Siebels, Claudia; Rommel, Oliver; Wernitz, Marcus; Hahn, Matthias

    1998-01-01

    To study the molecular basis of biotrophic nutrient uptake by plant parasitic rust fungi, the gene (Uf-PMA1) encoding the plasma membrane H+-ATPase from Uromyces fabae was isolated. Uf-PMA1 exists probably as a single gene. However, two nearly identical sequences were identified; the similarity apparently is due to two Uf-PMA1 alleles in the dikaryotic hyphae. Multiple Uf-PMA1 transcripts were observed during early rust development, and reduced amounts of a single Uf-PMA1 mRNA were observed i...

  6. Kinetic studies on the control of the bean rust fungus (Uromyces phaseoli L.) by an inhibitor of polyamine biosynthesis

    Science.gov (United States)

    Rajam, M. V.; Weinstein, L. H.; Galston, A. W.

    1986-01-01

    alpha-Difluoromethylornithine (DFMO), a specific and irreversible inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase, effectively inhibits mycelial growth of several phytopathogenic fungi on defined media in vitro and provides systemic protection of bean plants against infection by Uromyces phaseoli L. race 0 (MV Rajam, AW Galston 1985 Plant Cell Physiol 26: 683-692; MV Rajam et al. 1985 Proc Natl Acad Sci USA 82: 6874-6878). We now find that application of 0.5 millimolar DFMO to unifoliolate leaves of Pinto beans up to 3 days after inoculation with uredospores of U. phaseoli completely inhibits the growth of the pathogen, while application 4 or 5 days after inoculation results in partial protection against the pathogen. Spores do not germinate on the surface of unifoliolate leaves treated with DFMO 1 day before infection, but addition of spermidine to the DFMO treatments partially reverses the inhibitory effect. The titer of polyamines in bean plants did not decline after DFMO treatment; rather, putrescine and spermidine contents actually rose, probably due to the known but paradoxical stimulation of arginine decarboxylase activity by DFMO.

  7. Shotgun identification of proteins from uredospores of the bean rust Uromyces appendiculatus.

    Science.gov (United States)

    Cooper, Bret; Garrett, Wesley M; Campbell, Kimberly B

    2006-04-01

    We are interested in learning more about the proteome of Uromyces appendiculatus, the fungus that causes common bean rust. Knowledge of the proteins that differentiate life-cycle stages and distinguish infectious bodies such as uredospores, germlings, appressoria, and haustoria may be used to define host-pathogen interactions or serve as targets for chemical inhibition of the fungus. We have used 2-D nanoflowLC-MS/MS to identify more than 400 proteins from asexual uredospores. A majority of the proteins appear to have roles in protein folding or protein catabolism. We present a model by which an abundance of heat shock proteins and translation elongation factors may enhance a spore's ability to survive environmental stresses and rapidly initiate protein production upon germination.

  8. In situ chlorophyll fluorescence kinetics as a tool to quantify effects on photosynthesis in Euphorbia cyparissias by a parasitic infection of the rust fungus Uromyces pisi.

    Science.gov (United States)

    Zhori, Alba; Meco, Marjol; Brandl, Helmut; Bachofen, Reinhard

    2015-11-21

    Photosynthesis is the key process for plant growth and development. The determination of chlorophyll fluorescence kinetics allows the quantification of effects on photosynthetic processes triggered by environmental stress factors such as, e.g., the infection by fungal phytopathogens. The technique is non-invasive, rapid and well suited for experimental field work. Healthy and Uromyces-infected plants of Euphorbia cyparissias were monitored directly in situ in the field using rapid fluorescence kinetics. Non-infected healthy plants show a typical maximum value for the relative variable fluorescence Fv/Fm of around 0.8 with occasional variation between the leaves from the plant top towards the base, while infected plants exhibited a strong gradient to low values at the base. The photosynthetic performance index (PI) showed a higher heterogeneity within the leaves in both plant types. The non-invasive and rapid measurement of chlorophyll fluorescence induction allows characterizing the photosynthetic capacity of healthy and infected plants and of parts of them directly in the field. The PI, is highly sensitive not only concerning infection, but also towards other local environmental influences.

  9. Association of Faba Bean Rust ( Uromyces viciae-fabae ) with ...

    African Journals Online (AJOL)

    ... stage and field management practices. The mean incidence of the disease varied from 44.6% in Bedeno to 98% in Tullo, while severity of the disease varied from 12.7% in Bedeno to 65% in Gorogutu and Kurfachale districts. Logistic regression analysis for the association of rust incidence and severity with environmental ...

  10. Species of the genus Uromyces (Basidiomycota: Pucciniales) from ...

    African Journals Online (AJOL)

    During a survey of rust fungi from Leepa Valley, Azad Jammu and Kashmir (AJ and K), Pakistan, four species of Uromyces were found parasitizing four plant species. These include Uromyces appendiculatus on Vigna mungo, Uromyces capitatus on Desmodium elegans, Uromyces penniseti on Pennisetum lanatum and ...

  11. Protection against common bean rust conferred by a gene silencing method

    Science.gov (United States)

    Rust disease of the dry bean plant, Phaseolus vulgaris, is caused by the fungus Uromyces appendiculatus. The fungus acquires its nutrients and energy from bean leaves using a specialized cell structure, the haustorium, through which it secretes effector proteins that contribute to pathogenicity by ...

  12. Genome-wide profiling of histone modifications (H3K9me2 and H4K12ac) and gene expression in rust (uromyces appendiculatus) inoculated common bean (Phaseolus vulgaris L)

    OpenAIRE

    Ayyappan, Vasudevan; Kalavacharla, Venu (Kal); Thimmapuram, Jyothi; Bhide, Ketaki P; Sripathi, Venkateswara R.

    2015-01-01

    Histone modifications such as methylation and acetylation play a significant role in controlling gene expression in unstressed and stressed plants. Genome-wide analysis of such stress-responsive modifications and genes in non-model crops is limited. We report the genome-wide profiling of histone methylation (H3K9me2) and acetylation (H4K12ac) in common bean (Phaseolus vulgaris L.) under rust (Uromyces appendiculatus) stress using two high-throughput approaches, chromatin immunoprecipitation s...

  13. Differential response by Melaleuca quinquenervia trees to attack by the rust fungus Puccinia psidii in Florida

    Science.gov (United States)

    Melaleuca quinquenervia (melaleuca, paperbark tree) is an exotic invasive tree in Florida, Hawaii, and some Caribbean islands. Puccinia psidii (guava rust-fungus) is a Neotropical rust fungus, reported to attack many species in the Myrtaceae and one genus in the Heteropyxidaceae, both members of the...

  14. Genome-Wide Profiling of Histone Modifications (H3K9me2 and H4K12ac and Gene Expression in Rust (Uromyces appendiculatus Inoculated Common Bean (Phaseolus vulgaris L..

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    Vasudevan Ayyappan

    Full Text Available Histone modifications such as methylation and acetylation play a significant role in controlling gene expression in unstressed and stressed plants. Genome-wide analysis of such stress-responsive modifications and genes in non-model crops is limited. We report the genome-wide profiling of histone methylation (H3K9me2 and acetylation (H4K12ac in common bean (Phaseolus vulgaris L. under rust (Uromyces appendiculatus stress using two high-throughput approaches, chromatin immunoprecipitation sequencing (ChIP-Seq and RNA sequencing (RNA-Seq. ChIP-Seq analysis revealed 1,235 and 556 histone methylation and acetylation responsive genes from common bean leaves treated with the rust pathogen at 0, 12 and 84 hour-after-inoculation (hai, while RNA-Seq analysis identified 145 and 1,763 genes differentially expressed between mock-inoculated and inoculated plants. The combined ChIP-Seq and RNA-Seq analyses identified some key defense responsive genes (calmodulin, cytochrome p450, chitinase, DNA Pol II, and LRR and transcription factors (WRKY, bZIP, MYB, HSFB3, GRAS, NAC, and NMRA in bean-rust interaction. Differential methylation and acetylation affected a large proportion of stress-responsive genes including resistant (R proteins, detoxifying enzymes, and genes involved in ion flux and cell death. The genes identified were functionally classified using Gene Ontology (GO and EuKaryotic Orthologous Groups (KOGs. The Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analysis identified a putative pathway with ten key genes involved in plant-pathogen interactions. This first report of an integrated analysis of histone modifications and gene expression involved in the bean-rust interaction as reported here provides a comprehensive resource for other epigenomic regulation studies in non-model species under stress.

  15. Genome-Wide Profiling of Histone Modifications (H3K9me2 and H4K12ac) and Gene Expression in Rust (Uromyces appendiculatus) Inoculated Common Bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Ayyappan, Vasudevan; Kalavacharla, Venu; Thimmapuram, Jyothi; Bhide, Ketaki P; Sripathi, Venkateswara R; Smolinski, Tomasz G; Manoharan, Muthusamy; Thurston, Yaqoob; Todd, Antonette; Kingham, Bruce

    2015-01-01

    Histone modifications such as methylation and acetylation play a significant role in controlling gene expression in unstressed and stressed plants. Genome-wide analysis of such stress-responsive modifications and genes in non-model crops is limited. We report the genome-wide profiling of histone methylation (H3K9me2) and acetylation (H4K12ac) in common bean (Phaseolus vulgaris L.) under rust (Uromyces appendiculatus) stress using two high-throughput approaches, chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq). ChIP-Seq analysis revealed 1,235 and 556 histone methylation and acetylation responsive genes from common bean leaves treated with the rust pathogen at 0, 12 and 84 hour-after-inoculation (hai), while RNA-Seq analysis identified 145 and 1,763 genes differentially expressed between mock-inoculated and inoculated plants. The combined ChIP-Seq and RNA-Seq analyses identified some key defense responsive genes (calmodulin, cytochrome p450, chitinase, DNA Pol II, and LRR) and transcription factors (WRKY, bZIP, MYB, HSFB3, GRAS, NAC, and NMRA) in bean-rust interaction. Differential methylation and acetylation affected a large proportion of stress-responsive genes including resistant (R) proteins, detoxifying enzymes, and genes involved in ion flux and cell death. The genes identified were functionally classified using Gene Ontology (GO) and EuKaryotic Orthologous Groups (KOGs). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified a putative pathway with ten key genes involved in plant-pathogen interactions. This first report of an integrated analysis of histone modifications and gene expression involved in the bean-rust interaction as reported here provides a comprehensive resource for other epigenomic regulation studies in non-model species under stress.

  16. Microsatellite DNA suggests regional structure in the fusiform rust fungus Cronartium quercuum f. sp fusiforme

    Science.gov (United States)

    T.L Kubisiak; J.H. Roberds; P.C. Spaine; R.L. Doudrick

    2004-01-01

    This paper reports results obtained from microsatellite DNA analysis of genetic structure for populations of the native fungus Cronartium quercuum f. sp fusiforme infecting loblolly pine (Pinus taeda L.) over much of this host's natural range. Mostly all fusiform rust galls formed under field conditions are...

  17. Prehaustorial resistance to the wheat leaf rust fungus, Puccinia triticina, in Triticum monococcum (s.s.)

    NARCIS (Netherlands)

    Anker, C.C.; Niks, R.E.

    2001-01-01

    Diploid wheat, Triticum monococcum s.l., is a host for the wheat leaf rust fungus, Puccinia triticina. Some accessions have been reported to show a high degree of prehaustorial resistance. This is non-hypersensitivity resistance, which acts before the formation of haustoria by the pathogen. To

  18. Breeding for common bean (Phaseolus vulgaris L.) rust resistance in Brazil.

    OpenAIRE

    SOUZA, T. L. P. O.; FALEIRO, F. G.; DESSAUNE, S. N.; PAULA JUNIOR, T. J. de; MOREIRA, M. A.; E. G. BARROS

    2013-01-01

    Common bean is an economically, nutritionally, and socially important crop. It is grown in distinct regions and different seasons around the world by subsistence level farmers with low-technology input as well as by farmers that use high input technologies. One important factor that can limit the bean growing and drastically affect grain yields is the high number of destructive pathogens that attack and cause serious damage to the crop. Among them is bean rust, incited by the fungus Uromyces ...

  19. Host status of false brome grass to the leaf rust fungus Puccinia brachypodii and the stripe rust fungus P. Striiformis

    NARCIS (Netherlands)

    Barbieri, M.; Marcel, T.C.; Niks, R.E.

    2011-01-01

    Purple false brome grass (Brachypodium distachyon) has recently emerged as a model system for temperate grasses and is also a potential model plant to investigate plant interactions with economically important pathogens such as rust fungi. We determined the host status of five Brachypodium species

  20. Effector-mining in the poplar rust fungus Melampsora larici populina secretome

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    Cecile eLorrain

    2015-12-01

    Full Text Available The poplar leaf rust fungus, Melampsora larici-populina has been established as a tree-microbe interaction model. Understanding the molecular mechanisms controlling infection by pathogens appears essential for durable management of tree plantations. In biotrophic plant parasites, effectors are known to condition host cell colonization. Thus, investigation of candidate secreted effector proteins is a major goal in the poplar-poplar rust interaction. Unlike oomycetes, fungal effectors do not share conserved motifs and candidate prediction relies on a set of a priori criteria established from reported bona fide effectors. Secretome prediction, genome-wide analysis of gene families and transcriptomics of M. larici-populina have led to catalogues of more than a thousand secreted proteins. Automatized effector mining pipelines hold great promise for rapid and systematic identification and prioritization of candidate secreted effector proteins for functional characterization. In this review, we report on and discuss the current status of the poplar rust fungus secretome and prediction of candidate effectors in this species.

  1. Major transcriptome reprogramming underlies floral mimicry induced by the rust fungus Puccinia monoica in Boechera stricta.

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    Liliana M Cano

    Full Text Available Pucciniamonoica is a spectacular plant parasitic rust fungus that triggers the formation of flower-like structures (pseudoflowers in its Brassicaceae host plant Boecherastricta. Pseudoflowers mimic in shape, color, nectar and scent co-occurring and unrelated flowers such as buttercups. They act to attract insects thereby aiding spore dispersal and sexual reproduction of the rust fungus. Although much ecological research has been performed on P. monoica-induced pseudoflowers, this system has yet to be investigated at the molecular or genomic level. To date, the molecular alterations underlying the development of pseudoflowers and the genes involved have not been described. To address this, we performed gene expression profiling to reveal 256 plant biological processes that are significantly altered in pseudoflowers. Among these biological processes, plant genes involved in cell fate specification, regulation of transcription, reproduction, floral organ development, anthocyanin (major floral pigments and terpenoid biosynthesis (major floral volatile compounds were down-regulated in pseudoflowers. In contrast, plant genes involved in shoot, cotyledon and leaf development, carbohydrate transport, wax biosynthesis, cutin transport and L-phenylalanine metabolism (pathway that results in phenylethanol and phenylacetaldehyde volatile production were up-regulated. These findings point to an extensive reprogramming of host genes by the rust pathogen to induce floral mimicry. We also highlight 31 differentially regulated plant genes that are enriched in the biological processes mentioned above, and are potentially involved in the formation of pseudoflowers. This work illustrates the complex perturbations induced by rust pathogens in their host plants, and provides a starting point for understanding the molecular mechanisms of pathogen-induced floral mimicry.

  2. The haustorial transcriptomes of Uromyces appendiculatus and Phakopsora pachyrhizi and their candidate effector families.

    Science.gov (United States)

    Link, Tobias I; Lang, Patrick; Scheffler, Brian E; Duke, Mary V; Graham, Michelle A; Cooper, Bret; Tucker, Mark L; van de Mortel, Martijn; Voegele, Ralf T; Mendgen, Kurt; Baum, Thomas J; Whitham, Steven A

    2014-05-01

    Haustoria of biotrophic rust fungi are responsible for the uptake of nutrients from their hosts and for the production of secreted proteins, known as effectors, which modulate the host immune system. The identification of the transcriptome of haustoria and an understanding of the functions of expressed genes therefore hold essential keys for the elucidation of fungus-plant interactions and the development of novel fungal control strategies. Here, we purified haustoria from infected leaves and used 454 sequencing to examine the haustorial transcriptomes of Phakopsora pachyrhizi and Uromyces appendiculatus, the causal agents of soybean rust and common bean rust, respectively. These pathogens cause extensive yield losses in their respective legume crop hosts. A series of analyses were used to annotate expressed sequences, including transposable elements and viruses, to predict secreted proteins from the assembled sequences and to identify families of candidate effectors. This work provides a foundation for the comparative analysis of haustorial gene expression with further insights into physiology and effector evolution. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  3. Cloning of a putative hypersensitive induced reaction gene from wheat infected by stripe rust fungus.

    Science.gov (United States)

    Yu, Xiu-Mei; Yu, Xiu-Dao; Qu, Zhi-Peng; Huang, Xin-Jie; Guo, Jun; Han, Qing-Mei; Zhao, Jie; Huang, Li-Li; Kang, Zhen-Sheng

    2008-01-15

    The hypersensitive response (HR) is one of the most efficient forms of plant defense against biotrophic pathogens and results in localized cell death and the formation of necrotic lesions. In this study, a novel putative hypersensitive induced reaction (HIR) gene from wheat leaves infected by incompatible stripe rust pathogen CY23, designated as Ta-hir1, was identified by using rapid amplification of cDNA ends (RACE). Ta-hir1 encodes 284 amino acids, with a predicted molecular mass of 31.31 KDa. A phylogenetic analysis showed that Ta-hir1 was highly homologous to Hv-hir1 from barley at both cDNA and deduced amino-acid levels. Amino-acid sequence analysis of the wheat HIR protein indicated the presence of the SPFH (Stomatins, Prohibitins, Flotillins and HflK/C) protein domain typical for stomatins which served as a negative regulator of univalent cation permeability, especially for potassium. The expression profile of the Ta-hir1 transcript detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time polymerase chain reaction (real time-PCR), respectively, showed that the highest expression occurred 48 h post inoculation (hpi), which is consistent with our previous histopathology observations during the stripe rust fungus-wheat incompatible reaction.

  4. Unveiling common responses of Medicago truncatula to appropriate and inappropriate rust species

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    Maria Carlota eVaz Patto

    2014-11-01

    Full Text Available Little is known about the nature of effective defense mechanisms in legumes to pathogens of remotely related plant species. Some rust species are among pathogens with broad host range causing dramatic losses in various crop plants. To understand and compare the different host and nonhost resistance responses of legume species against rusts, we characterized the reaction of the model legume Medicago truncatula to one appropriate (Uromyces striatus and two inappropriate (U. viciae-fabae and U. lupinicolus rusts. We found that similar pre and post-haustorial mechanisms of resistance appear to be operative in M. truncatula against appropriate and inappropriate rust fungus. The appropriate U. striatus germinated better on M. truncatula accessions then the inappropriate U. viciae-fabae and U. lupinicolus, but once germinated, germ tubes of the three rusts had a similar level of success in finding stomata and forming an appressoria over a stoma. However responses to different inappropriate rust species also showed some specificity, suggesting a combination of non specific and specific responses underlying this legume nonhost resistance to rust fungi. Further genetic and expression analysis studies will contribute to the development of the necessary molecular tools to use the present information on host and nonhost resistance mechanisms to breed for broad-spectrum resistance to rust in legume species.

  5. Gene discovery in EST sequences from the wheat leaf rust fungus Puccinia triticina sexual spores, asexual spores and haustoria, compared to other rust and corn smut fungi

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    Wynhoven Brian

    2011-03-01

    Full Text Available Abstract Background Rust fungi are biotrophic basidiomycete plant pathogens that cause major diseases on plants and trees world-wide, affecting agriculture and forestry. Their biotrophic nature precludes many established molecular genetic manipulations and lines of research. The generation of genomic resources for these microbes is leading to novel insights into biology such as interactions with the hosts and guiding directions for breakthrough research in plant pathology. Results To support gene discovery and gene model verification in the genome of the wheat leaf rust fungus, Puccinia triticina (Pt, we have generated Expressed Sequence Tags (ESTs by sampling several life cycle stages. We focused on several spore stages and isolated haustorial structures from infected wheat, generating 17,684 ESTs. We produced sequences from both the sexual (pycniospores, aeciospores and teliospores and asexual (germinated urediniospores stages of the life cycle. From pycniospores and aeciospores, produced by infecting the alternate host, meadow rue (Thalictrum speciosissimum, 4,869 and 1,292 reads were generated, respectively. We generated 3,703 ESTs from teliospores produced on the senescent primary wheat host. Finally, we generated 6,817 reads from haustoria isolated from infected wheat as well as 1,003 sequences from germinated urediniospores. Along with 25,558 previously generated ESTs, we compiled a database of 13,328 non-redundant sequences (4,506 singlets and 8,822 contigs. Fungal genes were predicted using the EST version of the self-training GeneMarkS algorithm. To refine the EST database, we compared EST sequences by BLASTN to a set of 454 pyrosequencing-generated contigs and Sanger BAC-end sequences derived both from the Pt genome, and to ESTs and genome reads from wheat. A collection of 6,308 fungal genes was identified and compared to sequences of the cereal rusts, Puccinia graminis f. sp. tritici (Pgt and stripe rust, P. striiformis f. sp

  6. Patterns of genomic variation in the poplar rust fungus Melampsora larici-populina identify pathogenesis-related factors

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    Antoine ePersoons

    2014-09-01

    Full Text Available Melampsora larici-populina is a fungal pathogen responsible for foliar rust disease on poplar trees, which causes damage to forest plantations worldwide, particularly in Northern Europe. The reference genome of the isolate 98AG31 was previously sequenced using a whole genome shotgun strategy, revealing a large genome of 101 megabases containing 16,399 predicted genes, which included secreted protein genes representing poplar rust candidate effectors. In the present study, the genomes of 15 isolates collected over the past 20 years throughout the French territory, representing distinct virulence profiles, were characterized by massively parallel sequencing to assess genetic variation in the poplar rust fungus. Comparison to the reference genome revealed striking structural variations. Analysis of coverage and sequencing depth identified large missing regions between isolates related to the mating type loci. More than 611,824 single-nucleotide polymorphism (SNP positions were uncovered overall, indicating a remarkable level of polymorphism. Based on the accumulation of non-synonymous substitutions in coding sequences and the relative frequencies of synonymous and non-synonymous polymorphisms (i.e. PN/PS, we identify candidate genes that may be involved in fungal pathogenesis. Correlation between non-synonymous SNPs in genes encoding secreted proteins and pathotypes of the studied isolates revealed candidate genes potentially related to virulences 1, 6 and 8 of the poplar rust fungus.

  7. Ultrastructure of the Rust Fungus Puccinia miscanthi in the Teliospore Stage Interacting with the Biofuel Plant Miscanthus sinensis

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    Ki Woo Kim

    2015-09-01

    Full Text Available Interaction of the the rust fungus Puccinia miscanthi with the biofuel plant Miscanthus sinensis during the teliospore phase was investigated by light and electron microscopy. P. miscanthi telia were oval-shaped and present on both the adaxial and abaxial leaf surfaces. Teliospores were brown, one-septate (two-celled, and had pedicels attached to one end. Transmission electron microscopy revealed numerous electron-translucent lipid globules in the cytoplasm of teliospores. Extensive cell wall dissolution around hyphae was not observed in the host tissues beneath the telia. Hyphae were found between mesophyll cells in the leaf tissues as well as in host cells. Intracellular hyphae, possibly haustoria, possessed electron-dense fungal cell walls encased by an electron-transparent fibrillar extrahaustorial sheath that had an electron-dense extrahaustorial membrane. The infected host cells appeared to maintain their membrane-bound structures such as nuclei and chloroplasts. These results suggest that the rust fungus maintains its biotrophic phase with most mesophyll cells of M. sinensis. Such a nutritional mode would permit the rust fungus to obtain food reserves for transient growth in the course of host alteration.

  8. Protection Against Common Bean Rust Conferred by a Gene-Silencing Method.

    Science.gov (United States)

    Cooper, Bret; Campbell, Kimberly B

    2017-08-01

    Rust disease of the dry bean plant, Phaseolus vulgaris, is caused by the fungus Uromyces appendiculatus. The fungus acquires its nutrients and energy from bean leaves using a specialized cell structure, the haustorium, through which it secretes effector proteins that contribute to pathogenicity by defeating the plant immune system. Candidate effectors have been identified by DNA sequencing and motif analysis, and some candidates have been observed in infected leaves by mass spectrometry. To assess their roles in pathogenicity, we have inserted small fragments of genes for five candidates into Bean pod mottle virus. Plants were infected with recombinant virus and then challenged with U. appendiculatus. Virus-infected plants expressing gene fragments for four of five candidate effectors accumulated lower amounts of rust and had dramatically less rust disease. By contrast, controls that included a fungal gene fragment for a septin protein not expressed in the haustorium died from a synergistic reaction between the virus and the fungus. The results imply that RNA generated in the plant moved across the fungal haustorium to silence effector genes important to fungal pathogenicity. This study shows that four bean rust fungal genes encode pathogenicity determinants and that the expression of fungal RNA in the plant can be an effective method for protecting bean plants from rust.

  9. Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection

    OpenAIRE

    Nguyen Henry T; Cooper Bret; Xu Dong; Scheffler Brian; Campbell Kimberly B; Joshi Trupti; Thibivilliers Sandra; Stacey Gary

    2009-01-01

    Abstract Background Phaseolus vulgaris (common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized. Results A subtractive bean cDNA library composed of 10,5...

  10. Development of monitoring method of coffee leaf rust fungus (Hemileia vastatrix) infected area using satellite remote sensing

    Science.gov (United States)

    Katsuhama, N.; Ikeda, K.; Imai, M.; Watanabe, K.; Marpaung, F.; Yoshii, T.; Naruse, N.; Takahashi, Y.

    2016-12-01

    Since 2008, coffee leaf rust fungus (Hemileia vastatrix) has expanded its infection in Latin America, and early trimming and burning infected trees have been only effective countermeasures to prevent spreading infection. Although some researchers reported a case about the monitoring of coffee leaf rust using satellite remote sensing in 1970s, the spatial resolution was unsatisfied, and therefore, further technological development has been required. The purpose of this research is to develop effective method of discovering coffee leaf rust infected areas using satellite remote sensing. Annual changes of vegetation indices, i.e. Normalized Difference Vegetation Index (NDVI) and Modified Structure Insensitive Pigment Index (MSIPI), around Cuchumatanes Mountains, Republic of Guatemala, were analyzed by Landsat 7 images. Study fields in the research were limited by the coffee farm areas based on a previous paper about on site surveys in different damage areas. As the result of the analysis, the annual change of NDVI at the coffee farm areas with damages tended to be lower than those without damages. Moreover, the decline of NDVI appear from 2008 before the damage was reported. On the other hand, the change of MSIPI had no significant difference. NDVI and MSIPI are mainly related to the amount of chlorophyll and carotenoid in the leaves respectively. This means that the infected coffee leaves turned yellow without defoliation. This situation well matches the symptom of coffee leaf rust. The research concluded that the property of infected leaves turning yellow is effective to monitoring of infection areas by satellite remote sensing.

  11. Early insights into the genome sequence of Uromyces fabae

    Directory of Open Access Journals (Sweden)

    Tobias eLink

    2014-10-01

    Full Text Available Uromyces fabae is a major pathogen of broad bean, Vicia faba. U. fabae has served as a model among rust fungi to elucidate the development of infection structures, expression and secretion of cell wall degrading enzymes and gene expression. Using U. fabae, enormous progress was made regarding nutrient uptake and metabolism and in the search for secreted proteins and effectors. Here, we present results from a genome survey of U. fabae. Paired end Illumina sequencing provided 53 Gb of data. An assembly gave 59,735 scaffolds with a total length of 216 Mb. K-mer analysis estimated the genome size to be 329 Mb. Of a representative set of 23,153 predicted proteins we could annotate 10,209, and predict 599 secreted proteins. Clustering of the protein set indicates families of highly likely effectors. We also found new homologs of RTP1p, a prototype rust effector. The U. fabae genome will be an important resource for comparative analyses with U. appendiculatus and P. pachyrhizi and provide information regarding the phylogenetic relationship of the genus Uromyces with respect to other rust fungi already sequenced, namely Puccinia graminis f. sp. tritici, P. striiformis f. sp. tritici, Melampsora lini, and Melampsora larici-populina.

  12. Tracking the footsteps of an invasive plant pathogen: Intercontinental phylogeographic structure of the white-pine-blister-rust fungus, Cronartium ribicola

    Science.gov (United States)

    Bryce A. Richardson; Mee-Sook Kim; Ned B. Klopfenstein; Yuko Ota; Kwan Soo Woo; Richard C. Hamelin

    2009-01-01

    Presently, little is known about the worldwide genetic structure, diversity, or evolutionary relationships of the white-pineblister-rust fungus, Cronartium ribicola. A collaborative international effort is underway to determine the phylogeographic relationships among Asian, European, and North American sources of C. ribicola and...

  13. RAPD markers linked to a block of genes conferring rust resistance to the common bean

    Directory of Open Access Journals (Sweden)

    Faleiro Fábio Gelape

    2000-01-01

    Full Text Available Rust, caused by the fungus Uromyces appendiculatus, may cause a significant loss to common bean (Phaseolus vulgaris L. yield. RAPD markers tightly linked to the resistance genes may be used in breeding programs to aid the development of rust-resistant bean cultivars. In this sense, the objective of the present work was to identify RAPD markers linked to a rust resistance gene block present in the cultivar Ouro Negro. Two hundred and fourteen F2 individuals from a cross between the resistant cultivar Ouro Negro and the susceptible cultivar US Pinto 111 were inoculated with a mixture of eight races of U. appendiculatus. The segregation ratio obtained suggested that resistance is monogenic and dominant. Bulked segregant analysis was used in conjunction with the RAPD technique to search for markers linked to rust resistance genes. Two molecular markers flanking the rust resistance gene block were identified, one at 5.8 ± 1.6 cM (OX11(630 and the other at 7.7 ± 1.7 cM (OF10(1,050 of the gene. Simulated indirect selection efficiency in the F2 population using the two markers was 100%. The molecular markers identified in this work are currently being used for the selection of disease-resistant plants in the commom bean breeding program of the Federal University of Viçosa.

  14. Putative Rust Fungal Effector Proteins in Infected Bean and Soybean Leaves.

    Science.gov (United States)

    Cooper, Bret; Campbell, Kimberly B; Beard, Hunter S; Garrett, Wesley M; Islam, Nazrul

    2016-05-01

    The plant-pathogenic fungi Uromyces appendiculatus and Phakopsora pachyrhizi cause debilitating rust diseases on common bean and soybean. These rust fungi secrete effector proteins that allow them to infect plants, but their effector repertoires are not understood. The discovery of rust fungus effectors may eventually help guide decisions and actions that mitigate crop production loss. Therefore, we used mass spectrometry to identify thousands of proteins in infected beans and soybeans and in germinated fungal spores. The comparative analysis between the two helped differentiate a set of 24 U. appendiculatus proteins targeted for secretion that were specifically found in infected beans and a set of 34 U. appendiculatus proteins targeted for secretion that were found in germinated spores and infected beans. The proteins specific to infected beans included family 26 and family 76 glycoside hydrolases that may contribute to degrading plant cell walls. There were also several types of proteins with structural motifs that may aid in stabilizing the specialized fungal haustorium cell that interfaces the plant cell membrane during infection. There were 16 P. pachyrhizi proteins targeted for secretion that were found in infected soybeans, and many of these proteins resembled the U. appendiculatus proteins found in infected beans, which implies that these proteins are important to rust fungal pathology in general. This data set provides insight to the biochemical mechanisms that rust fungi use to overcome plant immune systems and to parasitize cells.

  15. Genome-Wide Profiling of Histone Modifications (H3K9me2 and H4K12ac) and Gene Expression in Rust (Uromyces appendiculatus) Inoculated Common Bean (Phaseolus vulgaris L.)

    National Research Council Canada - National Science Library

    Ayyappan, Vasudevan; Kalavacharla, Venu; Thimmapuram, Jyothi; Bhide, Ketaki P; Sripathi, Venkateswara R; Smolinski, Tomasz G; Manoharan, Muthusamy; Thurston, Yaqoob; Todd, Antonette; Kingham, Bruce

    2015-01-01

    ...) and RNA sequencing (RNA-Seq). ChIP-Seq analysis revealed 1,235 and 556 histone methylation and acetylation responsive genes from common bean leaves treated with the rust pathogen at 0, 12 and 84 hour-after-inoculation (hai...

  16. Genome-Wide Profiling of Histone Modifications (H3K9me2 and H4K12ac) and Gene Expression in Rust (Uromyces appendiculatus) Inoculated Common Bean (Phaseolus vulgaris L.): e0132176

    National Research Council Canada - National Science Library

    Vasudevan Ayyappan; Venu Kalavacharla; Jyothi Thimmapuram; Ketaki P Bhide; Venkateswara R Sripathi; Tomasz G Smolinski; Muthusamy Manoharan; Yaqoob Thurston; Antonette Todd; Bruce Kingham

    2015-01-01

    ...) and RNA sequencing (RNA-Seq). ChIP-Seq analysis revealed 1,235 and 556 histone methylation and acetylation responsive genes from common bean leaves treated with the rust pathogen at 0, 12 and 84 hour-after-inoculation (hai...

  17. An evaluation of the rust fungus Gymnoconia nitensas a potential biological control agent for alien Rubus species in Hawaii

    Science.gov (United States)

    Gardner, D.E.; Hodges, C.S.; Killgore, E.; Anderson, R.C.

    1997-01-01

    The rust fungus Gymnoconia nitens infects blackberry (Rubus argutus) systemically in regions of the continental United States, producing bright yellow–orange masses of spores on newly developing floricanes during springtime. In tests to determine the suitability of this rust as a biological control agent for R. penetransin Hawaii, a species now thought to be conspecific with R. argutus,rooted cuttings of the Hawaiian plants were grown at North Carolina State University, inoculated, and observed. Other introduced weedy Rubus spp. in Hawaii, including R. ellipticus, R. rosifolius, and R. glaucus,as well as the two endemic species R. hawaiensis and R. macraei,also were inoculated. No species of Rubusare of commercial importance in Hawaii, but the protection of the native species, of which R. macraei is rare, was of utmost concern. The native Hawaiian species did not survive well in North Carolina in this study, however. Later availability of a plant pathogen containment laboratory in Hawaii enabled similar tests to be conducted at that facility. In addition to the above species, R. spectabilis (salmonberry), a species native to the Pacific Northwest with which the Hawaiian Rubus spp. are thought to share a common ancestor, was inoculated in Hawaii. Infection with G. nitens under natural field conditions becomes apparent only when sporulation occurs on floricanes the second year following infection. However, experimental inoculation led to early responses of chlorotic leaf flecking and puckering, leaf and stem contortion, and stem gall formation, indicating the sensitivity of R. penetrans (=R. argutus), R. hawaiensis, and R. macraei to this rust. Apparent systemic infection also resulted in sporulation on one plant of R. macraei. Ability to attack the endemic species suggests that G. nitens would not be suitable for release in Hawaii as a biological control agent, at least on the islands with populations of the native species.

  18. Interaction of Uromyces phaseoli and Meloidogyne incognita on Bean.

    Science.gov (United States)

    Bookbinder, M G; Bloom, J R

    1980-07-01

    Uromyces phaseoli, the causal agent of bean rust, suppressed shoot and root growth of three bean cultivars, reducing root weight more than shoot weight. The greatest suppression of root weight was on the cultivar that appeared most susceptible by visual ratings of shoot symptoms. Meloidogyne incognita suppressed shoot and root growth of all test cultivars; root weight reductions differed among cultivars identical in susceptibility to this pathogen in root-gall rating tests. Infection of plants with both pathogens suppressed plant weights significantly more than did infection by either pathogen alone, evidencing an additive effect. U. phaseoli and M. incognita on the same plant influenced the reproduction of one another, presumably through effects on the host. Fungal uredia were reduced in size and sporulation capacity; M. incognita produced fewer root galls, and fewer eggs per egg mass.

  19. Marker-assisted molecular profiling and RNA-Seq reveal a disease resistance cluster associated with Uromyces appendiculatus infection in common bean Phaseolus vulgaris L

    Science.gov (United States)

    Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of common bean. The Ur-3 locus provides race specific resistance to fungal rust along wit...

  20. Marker-Assisted Molecular Profiling, Deletion Mutant Analysis, and RNA-Seq Reveal a Disease Resistance Cluster Associated with Uromyces appendiculatus Infection in Common Bean Phaseolus vulgaris L.

    OpenAIRE

    Todd, Antonette R.; Donofrio, Nicole; Sripathi, Venkateswara R.; McClean, Phillip E.; Lee, Rian K.; Pastor-Corrales, Marcial; Kalavacharla, Venu

    2017-01-01

    Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance to virulent strains or races of the bean rust pathogen along with Crg, (Complements resistance gene), which is required for Ur-3-mediated rust resistance. In this study, we inoculated two common bean genotypes (resist...

  1. Evaluation of Snap Bean Genotypes Combining Rust Resistance and Heat Tolerance Traits in East Africa

    Science.gov (United States)

    The major biotic and abiotic constraints to snap bean production in East Africa include diseases such as common bean rust (caused by Uromyces appendiculatus) and high ambient temperatures that cause heat stress. Rust resistant snap beans that perform well under both cool and hot agro-ecological cond...

  2. Investigating the host-range of the rust fungus Puccinia psidii sensu lato across tribes of the family Myrtaceae present in Australia.

    Science.gov (United States)

    Morin, Louise; Aveyard, Ruth; Lidbetter, Jonathan R; Wilson, Peter G

    2012-01-01

    The exotic rust fungus Puccinia psidii sensu lato was first detected in Australia in April 2010. This study aimed to determine the host-range potential of this accession of the rust by testing its pathogenicity on plants of 122 taxa, representative of the 15 tribes of the subfamily Myrtoideae in the family Myrtaceae. Each taxon was tested in two separate trials (unless indicated otherwise) that comprised up to five replicates per taxon and six replicates of a positive control (Syzygium jambos). No visible symptoms were observed on the following four taxa in either trial: Eucalyptus grandis×camaldulensis, E. moluccana, Lophostemon confertus and Sannantha angusta. Only small chlorotic or necrotic flecks without any uredinia (rust fruiting bodies) were observed on inoculated leaves of seven other taxa (Acca sellowiana, Corymbia calophylla 'Rosea', Lophostemon suaveolens, Psidium cattleyanum, P. guajava 'Hawaiian' and 'Indian', Syzygium unipunctatum). Fully-developed uredinia were observed on all replicates across both trials of 28 taxa from 8 tribes belonging to the following 17 genera: Agonis, Austromyrtus, Beaufortia, Callistemon, Calothamnus, Chamelaucium, Darwinia, Eucalyptus, Gossia, Kunzea, Leptospermum, Melaleuca, Metrosideros, Syzygium, Thryptomene, Tristania, Verticordia. In contrast, the remaining 83 taxa inoculated, including the majority of Corymbia and Eucalyptus species, developed a broad range of symptoms, often across the full spectrum, from fully-developed uredinia to no visible symptoms. These results were encouraging as they indicate that some levels of genetic resistance to the rust possibly exist in these taxa. Overall, our results indicated no apparent association between the presence or absence of disease symptoms and the phylogenetic relatedness of taxa. It is most likely that the majority of the thousands of Myrtaceae species found in Australia have the potential to become infected to some degree by the rust, although this wide host range may

  3. A novel beta-glucosidase in Uromyces fabae : feast or fight?

    OpenAIRE

    Haerter, Ariane C.; Voegele, Ralf T.

    2004-01-01

    Efficient nutrient mobilization is a key element for biotrophic plant parasites such as the rust fungi. In the course of a cDNA library screen for elements involved in sugar utilization in Uromyces fabae, we identified a sequence with homology to beta-glucosidases. Full-length genomic and cDNA clones of the gene, termed BGL1, were isolated and sequenced. The BGL1 gene comprises 3,372 nucleotides, including nine introns. The open reading frame encompasses 2,532 bases and codes for a polypeptid...

  4. Control of Bean Rust using Antibiotics Produced by Bacillus and ...

    African Journals Online (AJOL)

    Antibiotic culture filtrates produced by Bacillus (CA5) and Streptomyces spp. were tested for translocation and persistence when applied on snap beans inoculated with rust (Uromyces appendiculatus) in greenhouse pot experiments. The antibiotics were applied on the first trifoliate leaves and translocation was assessed as ...

  5. Control of Bean Rust using Antibiotics Produced by Bacillus and ...

    African Journals Online (AJOL)

    MICHAEL

    ABSTRACT: Antibiotic culture filtrates produced by Bacillus (CA5) and Streptomyces spp. were tested for translocation and persistence when applied on snap beans inoculated with rust (Uromyces appendiculatus) in greenhouse pot experiments. The antibiotics were applied on the first trifoliate leaves and translocation was ...

  6. Fine Mapping of Ur-3, a Historically Important Rust Resistance Locus in Common Bean

    OpenAIRE

    Hurtado-Gonzales, Oscar P.; Giseli Valentini; Gilio, Thiago A. S.; Martins, Alexandre M; Qijian Song; Pastor-Corrales, Marcial A.

    2016-01-01

    Bean rust, caused by Uromyces appendiculatus, is a devastating disease of common bean (Phaseolus vulgaris) in the Americas and Africa. The historically important Ur-3 gene confers resistance to many races of the highly variable bean rust pathogen that overcome other rust resistance genes. Existing molecular markers tagging Ur-3 for use in marker-assisted selection produce false results. Here, we describe the fine mapping of the Ur-3 locus for the development of highly accurate markers linked ...

  7. Targeting gene combinations for broad spectrum rust resistance in heat tolerant snap beans developed for tropical environments

    Science.gov (United States)

    The Common bean rust disease, caused by Uromyces appendiculatus, and heat stress, caused by high ambient temperature, constrain snap bean (Phaseolus vulgaris L.) production in many areas in tropical and temperate zones. Bean rust and heat stress often occur within the same production regions, such ...

  8. Tagging and mapping of SSR marker for rust resistance gene in lentil (Lens culinaris Medikus subsp. culinaris).

    Science.gov (United States)

    Dikshit, H K; Singh, Akanksha; Singh, D; Aski, M; Jain, Neelu; Hegde, V S; Basandrai, A K; Basandrai, D; Sharma, T R

    2016-06-01

    Lentil, as an economical source of protein, minerals and vitamins, plays important role in nutritional security of the common man. Grown mainly in West Asia, North Africa (WANA) region and South Asia, it suffers from several biotic stresses such as wilt, rust, blight and broomrape. Lentil rust caused by autoecious fungus Uromyces viciae fabae (Pers.) Schroet is a serious lentil disease in Algeria, Bangladesh, Ethiopia, India, Italy, Morocco, Pakistan and Nepal. The disease symptoms are observed during flowering and early podding stages. Rust causes severe yield losses in lentil. It can only be effectively controlled by identifying the resistant source, understanding its inheritance and breeding for host resistance. The obligate parasitic nature of pathogen makes it difficult to maintain the pathogen in culture and to apply it to screen segregating progenies under controlled growth conditions. Hence, the use of molecular markers will compliment in identification of resistant types in different breeding programs. Here, we studied the inheritance of resistance to rust in lentil using F₁, F₂ and F₂:₃ from cross PL 8 (susceptible) x L 4149 (resistant) varieties. The phenotyping of lentil population was carried out at Sirmour, India. The result of genetic analysis revealed that a single dominant gene controls rust resistance in lentil genotype L 4149. The F2 population from this cross was used to tag and map the rust resistance gene using SSR and SRAP markers. Markers such as 270 SRAP and 162 SSR were studied for polymorphism and 101 SRAP and 33 SSRs were found to be polymorphic between the parents. Two SRAP and two SSR markers differentiated the resistant and susceptible bulks. SSR marker Gllc 527 was estimated to be linked to rust resistant locus at a distance of 5.9 cM. The Gllc 527 marker can be used for marker assisted selection for rust resistance; however, additional markers closer to rust resistant locus are required. The markers linked to the rust

  9. Economic analysis of the proposed rule to prevent arrival of new genetic strains of the rust fungus Puccinia psidii in Hawai'i.

    Science.gov (United States)

    Burnett, Kimberly; D'Evelyn, Sean; Loope, Lloyd; Wada, Christopher A.

    2012-01-01

    Since its first documented introduction to Hawai‘i in 2005, the rust fungus P. psidii has already severely damaged Syzygium jambos (Indian rose apple) trees and the federally endangered Eugenia koolauensis (nioi). Fortunately, the particular strain has yet to cause serious damage to ‘ōhi‘a, which comprises roughly 80% of the state’s native forests and covers 400,000 ha. Although the rust has affected less than 5% of Hawaii’s ‘ōhi‘a trees thus far, the introduction of more virulent strains and the genetic evolution of the current strain are still possible. Since the primary pathway of introduction is Myrtaceae plant material imported from outside the state, potential damage to ‘ohi‘a can be minimized by regulating those high-risk imports. We discuss the economic impact on the state’s florist, nursery, landscaping, and forest plantation industries of a proposed rule that would ban the import of non-seed Myrtaceae plant material and require a one-year quarantine of seeds. Our analysis suggests that the benefits to the forest plantation industry of a complete ban on non-seed material would likely outweigh the costs to other affected sectors, even without considering the reduction in risk to ‘ōhi‘a. Incorporating the value of ‘ōhi‘a protection would further increase the benefit-cost ratio in favor of an import ban.

  10. Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection

    Science.gov (United States)

    Thibivilliers, Sandra; Joshi, Trupti; Campbell, Kimberly B; Scheffler, Brian; Xu, Dong; Cooper, Bret; Nguyen, Henry T; Stacey, Gary

    2009-01-01

    Background Phaseolus vulgaris (common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized. Results A subtractive bean cDNA library composed of 10,581 unisequences was constructed and enriched in sequences regulated by either bean rust race 41, a virulent strain, or race 49, an avirulent strain on cultivar Early Gallatin carrying the resistance gene Ur-4. The construction of this library allowed the identification of 6,202 new bean ESTs, significantly adding to the available sequences for this plant. Regulation of selected bean genes in response to bean rust infection was confirmed by qRT-PCR. Plant gene expression was similar for both race 41 and 49 during the first 48 hours of the infection process but varied significantly at the later time points (72–96 hours after inoculation) mainly due to the presence of the Avr4 gene in the race 49 leading to a hypersensitive response in the bean plants. A biphasic pattern of gene expression was observed for several genes regulated in response to fungal infection. Conclusion The enrichment of the public database with over 6,000 bean ESTs significantly adds to the genomic resources available for this important crop plant. The analysis of these genes in response to bean rust infection provides a foundation for further studies of the mechanism of fungal disease resistance. The expression pattern of 90 bean genes upon rust infection shares several features with other legumes infected by biotrophic fungi. This finding suggests that the P. vulgaris-U. appendiculatus pathosystem could serve as a model to explore legume-rust interaction. PMID:19397807

  11. Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection.

    Science.gov (United States)

    Thibivilliers, Sandra; Joshi, Trupti; Campbell, Kimberly B; Scheffler, Brian; Xu, Dong; Cooper, Bret; Nguyen, Henry T; Stacey, Gary

    2009-04-27

    Phaseolus vulgaris (common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized. A subtractive bean cDNA library composed of 10,581 unisequences was constructed and enriched in sequences regulated by either bean rust race 41, a virulent strain, or race 49, an avirulent strain on cultivar Early Gallatin carrying the resistance gene Ur-4. The construction of this library allowed the identification of 6,202 new bean ESTs, significantly adding to the available sequences for this plant. Regulation of selected bean genes in response to bean rust infection was confirmed by qRT-PCR. Plant gene expression was similar for both race 41 and 49 during the first 48 hours of the infection process but varied significantly at the later time points (72-96 hours after inoculation) mainly due to the presence of the Avr4 gene in the race 49 leading to a hypersensitive response in the bean plants. A biphasic pattern of gene expression was observed for several genes regulated in response to fungal infection. The enrichment of the public database with over 6,000 bean ESTs significantly adds to the genomic resources available for this important crop plant. The analysis of these genes in response to bean rust infection provides a foundation for further studies of the mechanism of fungal disease resistance. The expression pattern of 90 bean genes upon rust infection shares several features with other legumes infected by biotrophic fungi. This finding suggests that the P. vulgaris-U. appendiculatus pathosystem could serve as a model to explore legume-rust interaction.

  12. Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection

    Directory of Open Access Journals (Sweden)

    Nguyen Henry T

    2009-04-01

    Full Text Available Abstract Background Phaseolus vulgaris (common bean is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust, have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized. Results A subtractive bean cDNA library composed of 10,581 unisequences was constructed and enriched in sequences regulated by either bean rust race 41, a virulent strain, or race 49, an avirulent strain on cultivar Early Gallatin carrying the resistance gene Ur-4. The construction of this library allowed the identification of 6,202 new bean ESTs, significantly adding to the available sequences for this plant. Regulation of selected bean genes in response to bean rust infection was confirmed by qRT-PCR. Plant gene expression was similar for both race 41 and 49 during the first 48 hours of the infection process but varied significantly at the later time points (72–96 hours after inoculation mainly due to the presence of the Avr4 gene in the race 49 leading to a hypersensitive response in the bean plants. A biphasic pattern of gene expression was observed for several genes regulated in response to fungal infection. Conclusion The enrichment of the public database with over 6,000 bean ESTs significantly adds to the genomic resources available for this important crop plant. The analysis of these genes in response to bean rust infection provides a foundation for further studies of the mechanism of fungal disease resistance. The expression pattern of 90 bean genes upon rust infection shares several features with other legumes infected by biotrophic fungi. This finding suggests that the P. vulgaris-U. appendiculatus pathosystem could serve as a model to explore legume-rust interaction.

  13. 77 FR 46339 - Chrysanthemum White Rust Regulatory Status and Restrictions

    Science.gov (United States)

    2012-08-03

    ... Chrysanthemum White Rust Regulatory Status and Restrictions AGENCY: Animal and Plant Health Inspection Service... chrysanthemum white rust (CWR) outbreaks and the importation of plant material that is a host of CWR... filamentous rust fungus and obligate parasite that is the causal agent of chrysanthemum white rust (CWR), an...

  14. Genetic structure of the poplar rust fungus Melampsora larici-populina: evidence for isolation by distance in Europe and recent founder effects overseas.

    Science.gov (United States)

    Barrès, Benoît; Halkett, Fabien; Dutech, Cyril; Andrieux, Axelle; Pinon, Jean; Frey, Pascal

    2008-09-01

    Dispersal has a great impact on the genetic structure of populations, but remains difficult to estimate by direct measures. In particular, gradual and stochastic dispersal are often difficult to assess and to distinguish, although they have different evolutionary consequences. Plant pathogens, especially rust fungi, are suspected to display both dispersal modes, though on different spatial scales. In this study, we inferred dispersal capacities of the poplar rust fungus Melampsora larici-populina by examining the genetic diversity and structure of 13 populations from eight European and two overseas countries in the Northern hemisphere. M. larici-populina was sampled from both cultivated hybrid poplars and on the wild host, Populus nigra. The populations were analyzed with 11 microsatellite and 8 virulence markers. Although isolates displayed different virulence profiles according to the host plant, neutral markers revealed little population differentiation with respect to the type of host. This suggests an absence of reproductive isolation between populations sampled from cultivated and wild poplars. Conversely, studying the relationship between geographic and genetic structure allowed us to distinguish between isolation by distance (IBD) patterns and long distance dispersal (LDD) events. The European populations exhibited a significant IBD pattern, suggesting a regular and gradual dispersal of the pathogen over this spatial scale. Nonetheless, the genetic differentiation between these populations was low, suggesting an important gene flow on a continental scale. The two overseas populations from Iceland and Canada were shown to result from rare LDD events, and exhibited signatures of strong founder effects. Furthermore, the high genetic differentiation between both populations suggested that these two recent introductions were independent. This study illustrated how the proper use of population genetics methods can enable contrasted dispersal modes to be revealed.

  15. Identification of markers associated with genes for rust resistance in lens culinaris medik

    Science.gov (United States)

    Lentil rust caused by Uromyces vicia-fabae (Pers.) Schroet is one of the most important diseases of lentil in South Asia, North Africa and East Africa. This disease is usually observed during late flowering and early podding stages. Early infection accompanied by favorable environmental conditions c...

  16. Confocal microscopy of Spitzenkörper dynamics during growth and differentiation of rust fungi

    NARCIS (Netherlands)

    Dijksterhuis, J

    The membrane-selective fluorescent dye FM4-64, N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)py ridium dibromide, was used to stain the apical vesicle cluster within the specialized Spitzenkorper of the germ tube of the rust fungi Uromyces vignae and Puccinia graminis f. sp.

  17. Amino acid uptake in rust fungi

    Science.gov (United States)

    Struck, Christine

    2015-01-01

    The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia, or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid transporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways. PMID:25699068

  18. Amino acid uptake in rust fungi

    Directory of Open Access Journals (Sweden)

    Christine eStruck

    2015-02-01

    Full Text Available The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid tranporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways.

  19. Phylogenetic studies in Ravenelia esculenta and related rust fungi

    OpenAIRE

    Gandhe, K. R.; Kuvalekar, Aniket

    2007-01-01

    Ravenelia esculenta Naras. and Thium. is a rust fungus, which infects mostly thorns, inflorescences, flowers and fruits of Acacia eburnea Willd. Aecial stages of the rust produce hypertrophy in infected parts. DNA of the rust fungus was isolated from aeciospores by ‘freeze thaw’ method. 18S rDNA was amplified and sequenced by automated DNA sequencer. BLAST of the sequence at NCBI retrieved 96 sequences producing significant alignments. Multiple sequence alignment of these sequences was done b...

  20. 75 FR 29191 - Black Stem Rust; Additions of Rust-Resistant Varieties

    Science.gov (United States)

    2010-05-25

    ... by a fungus that reduces the quality and yield of infected wheat, oat, barley, and rye crops. In... to the list of rust-resistant Mahonia species or cultivars. The nursery and floriculture industries... determined to be rust-resistant. The introduction and spread of plant pests can result in damage to crops and...

  1. Species of the genus Uromyces (Basidiomycota: Pucciniales) from ...

    African Journals Online (AJOL)

    use

    2011-06-10

    Jun 10, 2011 ... Uromyces penniseti S. Ahmad, Biologia, Lahore 6(2): 125 (1961). [1960] (Figure 3). Spermogonia and aecia not seen. Uredinia amphigenous, scattered, covered by ruptured epidermis, golden brown, naked,. 0.08 - 0.1 × 0.095 - 0.15 mm. Urediniospores globose to subglobose or ovoid, pale brown, 18 - 24 ...

  2. Genome-Wide Analysis of Simple Sequence Repeats and Efficient Development of Polymorphic SSR Markers Based on Whole Genome Re-Sequencing of Multiple Isolates of the Wheat Stripe Rust Fungus.

    Science.gov (United States)

    Luo, Huaiyong; Wang, Xiaojie; Zhan, Gangming; Wei, Guorong; Zhou, Xinli; Zhao, Jing; Huang, Lili; Kang, Zhensheng

    2015-01-01

    The biotrophic parasitic fungus Puccinia striiformis f. sp. tritici (Pst) causes stripe rust, a devastating disease of wheat, endangering global food security. Because the Pst population is highly dynamic, it is difficult to develop wheat cultivars with durable and highly effective resistance. Simple sequence repeats (SSRs) are widely used as molecular markers in genetic studies to determine population structure in many organisms. However, only a small number of SSR markers have been developed for Pst. In this study, a total of 4,792 SSR loci were identified using the whole genome sequences of six isolates from different regions of the world, with a marker density of one SSR per 22.95 kb. The majority of the SSRs were di- and tri-nucleotide repeats. A database containing 1,113 SSR markers were established. Through in silico comparison, the previously reported SSR markers were found mainly in exons, whereas the SSR markers in the database were mostly in intergenic regions. Furthermore, 105 polymorphic SSR markers were confirmed in silico by their identical positions and nucleotide variations with INDELs identified among the six isolates. When 104 in silico polymorphic SSR markers were used to genotype 21 Pst isolates, 84 produced the target bands, and 82 of them were polymorphic and revealed the genetic relationships among the isolates. The results show that whole genome re-sequencing of multiple isolates provides an ideal resource for developing SSR markers, and the newly developed SSR markers are useful for genetic and population studies of the wheat stripe rust fungus.

  3. Genome-Wide Analysis of Simple Sequence Repeats and Efficient Development of Polymorphic SSR Markers Based on Whole Genome Re-Sequencing of Multiple Isolates of the Wheat Stripe Rust Fungus.

    Directory of Open Access Journals (Sweden)

    Huaiyong Luo

    Full Text Available The biotrophic parasitic fungus Puccinia striiformis f. sp. tritici (Pst causes stripe rust, a devastating disease of wheat, endangering global food security. Because the Pst population is highly dynamic, it is difficult to develop wheat cultivars with durable and highly effective resistance. Simple sequence repeats (SSRs are widely used as molecular markers in genetic studies to determine population structure in many organisms. However, only a small number of SSR markers have been developed for Pst. In this study, a total of 4,792 SSR loci were identified using the whole genome sequences of six isolates from different regions of the world, with a marker density of one SSR per 22.95 kb. The majority of the SSRs were di- and tri-nucleotide repeats. A database containing 1,113 SSR markers were established. Through in silico comparison, the previously reported SSR markers were found mainly in exons, whereas the SSR markers in the database were mostly in intergenic regions. Furthermore, 105 polymorphic SSR markers were confirmed in silico by their identical positions and nucleotide variations with INDELs identified among the six isolates. When 104 in silico polymorphic SSR markers were used to genotype 21 Pst isolates, 84 produced the target bands, and 82 of them were polymorphic and revealed the genetic relationships among the isolates. The results show that whole genome re-sequencing of multiple isolates provides an ideal resource for developing SSR markers, and the newly developed SSR markers are useful for genetic and population studies of the wheat stripe rust fungus.

  4. TaLHY, a 1R-MYB Transcription Factor, Plays an Important Role in Disease Resistance against Stripe Rust Fungus and Ear Heading in Wheat.

    Directory of Open Access Journals (Sweden)

    Zijin Zhang

    Full Text Available LHY (late elongated hypocotyl is an important gene that regulates and controls biological rhythms in plants. Additionally, LHY is highly expressed in the SSH (suppression subtractive hybridization cDNA library-induced stripe rust pathogen (CYR32 in our previous research. To identify the function of the LHY gene in disease resistance against stripe rust, we used RACE-PCR technology to clone TaLHY in the wheat variety Chuannong19. The cDNA of TaLHY is 3085 bp long with an open reading frame of 1947 bp. TaLHY is speculated to encode a 70.3 kDa protein of 648 amino acids , which has one typical plant MYB-DNA binding domain; additionally, phylogenetic tree shows that TaLHY has the highest homology with LHY of Brachypodium distachyon(BdLHY-like. Quantitative fluorescence PCR indicates that TaLHY has higher expression in the leaf, ear and stem of wheat but lower expression in the root. Infestation of CYR32 can result in up-regulated expression of TaLHY, peaking at 72 h. Using VIGS (virus-induced gene silencing technology to disease-resistant wheat in the fourth leaf stage, plants with silenced TaLHY cannot complete their heading stage. Through the compatible interaction with the stripe rust physiological race CYR32, Chuannong 19 loses its immune capability toward the stripe rust pathogen, indicating that TaLHY may regulate and participate in the heading of wheat, as well as the defense responses against stripe rust infection.

  5. TaLHY, a 1R-MYB Transcription Factor, Plays an Important Role in Disease Resistance against Stripe Rust Fungus and Ear Heading in Wheat.

    Science.gov (United States)

    Zhang, Zijin; Chen, Jieming; Su, Yongying; Liu, Hanmei; Chen, Yanger; Luo, Peigao; Du, Xiaogang; Wang, Dan; Zhang, Huaiyu

    2015-01-01

    LHY (late elongated hypocotyl) is an important gene that regulates and controls biological rhythms in plants. Additionally, LHY is highly expressed in the SSH (suppression subtractive hybridization) cDNA library-induced stripe rust pathogen (CYR32) in our previous research. To identify the function of the LHY gene in disease resistance against stripe rust, we used RACE-PCR technology to clone TaLHY in the wheat variety Chuannong19. The cDNA of TaLHY is 3085 bp long with an open reading frame of 1947 bp. TaLHY is speculated to encode a 70.3 kDa protein of 648 amino acids , which has one typical plant MYB-DNA binding domain; additionally, phylogenetic tree shows that TaLHY has the highest homology with LHY of Brachypodium distachyon(BdLHY-like). Quantitative fluorescence PCR indicates that TaLHY has higher expression in the leaf, ear and stem of wheat but lower expression in the root. Infestation of CYR32 can result in up-regulated expression of TaLHY, peaking at 72 h. Using VIGS (virus-induced gene silencing) technology to disease-resistant wheat in the fourth leaf stage, plants with silenced TaLHY cannot complete their heading stage. Through the compatible interaction with the stripe rust physiological race CYR32, Chuannong 19 loses its immune capability toward the stripe rust pathogen, indicating that TaLHY may regulate and participate in the heading of wheat, as well as the defense responses against stripe rust infection.

  6. Coupling- and repulsion-phase RAPDs for marker-assisted selection of PI 181996 rust resistance in common bean.

    Science.gov (United States)

    Johnson, E; Miklas, P N; Stavely, J R; Martinez-Cruzado, J C

    1995-04-01

    The Guatemalan black bean (Phaseolus vulgaris L.) plant introduction (PI) 181996 is resistant to all known US races of the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger var. appendiculatus [syn. U. phaseoli (Reben) Wint.]. We report on two random amplified polymorphic DNA (RAPD) markers OAC20490 tightly linked (no recombinants) in coupling phase and OAE19890 linked in repulsion phase (at 6.2±2.8 cM) to PI 181996 rust resistance. These RAPDs, generated by single decamer primers in the polymerase chain reaction, were identified in near-isogenic bulks of non-segregating resistant and susceptible BC4F2 (NX-040*4/PI 181996) lines. Linkage of the RAPD markers was confirmed by screening 19 BC4F2 and 57 BC4F3 individuals segregating for PI 181996 resistance. Utility of the RAPDs OAC20490 and OAE19890 was investigated in a diverse group of common bean cultivars and lines. All cultivars into which the PI 181996 resistance was introgressed had the RAPD OAC20490. A RAPD similar in size to OAC20490, observed in some susceptible common bean lines, was confirmed by Southern blotting to be homologous to the RAPD OAC20490. Use of the RAPDs OAC20490 and OAE19890 in marker-assisted selection (MAS) is proposed. The coupling-phase RAPD is most useful for MAS of resistant BCnF1individuals during traditional backcross breeding. The repulsion-phase RAPD has greatest utility in MAS of homozygous-resistant individuals in F2 or later-segregating generations.

  7. Marker-Assisted Molecular Profiling, Deletion Mutant Analysis, and RNA-Seq Reveal a Disease Resistance Cluster Associated with Uromyces appendiculatus Infection in Common Bean Phaseolus vulgaris L.

    Science.gov (United States)

    Todd, Antonette R; Donofrio, Nicole; Sripathi, Venkateswara R; McClean, Phillip E; Lee, Rian K; Pastor-Corrales, Marcial; Kalavacharla, Venu Kal

    2017-05-23

    Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance to virulent strains or races of the bean rust pathogen along with Crg, (Complements resistance gene), which is required for Ur-3-mediated rust resistance. In this study, we inoculated two common bean genotypes (resistant "Sierra" and susceptible crg) with rust race 53 of U. appendiculatus, isolated leaf RNA at specific time points, and sequenced their transcriptomes. First, molecular markers were used to locate and identify a 250 kb deletion on chromosome 10 in mutant crg (which carries a deletion at the Crg locus). Next, we identified differential expression of several disease resistance genes between Mock Inoculated (MI) and Inoculated (I) samples of "Sierra" leaf RNA within the 250 kb delineated region. Both marker assisted molecular profiling and RNA-seq were used to identify possible transcriptomic locations of interest regarding the resistance in the common bean to race 53. Identification of differential expression among samples in disease resistance clusters in the bean genome may elucidate significant genes underlying rust resistance. Along with preserving favorable traits in the crop, the current research may also aid in global sustainability of food stocks necessary for many populations.

  8. Reaction of common bean varieties ( Phaseolus vulgaris L. to the infection for Uromyces phaseoli (Pers. Wint var. typica Arth

    Directory of Open Access Journals (Sweden)

    Arth Cabrera

    2014-01-01

    Full Text Available It was evaluated the reaction of twenty-five common bean varieties to Uromyces phaseoli (Pers.Wintvar. typica Arth infection using the methodology informed by the Colombian International Center of Tropical Agriculture (CIAT. These experiments were developed in the Agricultural Experimental Station belonging to the Agricultural Sciences Faculty of Las Villas Central University, under a design of random blocks with four repetitions in the period between January to April 2011. The evaluations of infection intensity and pustule type were carried out weekly starting from the beginning of disease symptoms in 15 plants for varieties. Results evidenced differences in the response of varieties as well as a different behavior to the infection for this phytopathogen fungus. Guama 23 variety was classified as resistant highly to the infection for U. phaseoli. This work constitutes a fundamental tool for future programs on genetic improvement of common bean cultivation in Cuba.

  9. Rust essentials

    CERN Document Server

    Balbaert, Ivo

    2015-01-01

    This book is intended for software developers interested in systems level and application programming, and are looking for a quick entry into using Rust and understanding the core features of the framework. It is assumed that you have a basic understanding of Java, C#, Ruby, Python or JavaScript.

  10. Fighting Asian soybean rust

    Directory of Open Access Journals (Sweden)

    Caspar eLangenbach

    2016-06-01

    Full Text Available Phakopsora pachyrhizi is a biotrophic fungus provoking Asian soybean rust (SBR disease. SBR poses a major threat to global soybean production. Though several resistance genes provided soybean immunity to certain P. pachyrhizi races, the pathogen swiftly overcame this resistance. Therefore, fungicides are the only current means to control SBR. However, insensitivity to fungicides is soaring in P. pachyrhizi and, therefore, alternative measures are needed for SBR control. In this article, we discuss the different approaches for fighting SBR and their potential, disadvantages, and advantages over other measures. These encompass conventional breeding for SBR resistance, transgenic approaches, exploitation of transcription factors, secondary metabolites, and antimicrobial peptides, RNAi/HIGS, and biocontrol strategies. It seems that an integrating approach exploiting different measures is likely to provide the best possible means for the effective control of SBR.

  11. Scaling of photosynthesis and constitutive and induced volatile emissions with severity of leaf infection by rust fungus (Melampsora larici-populina) in Populus balsamifera var. suaveolens.

    Science.gov (United States)

    Jiang, Yifan; Ye, Jiayan; Veromann, Linda-Liisa; Niinemets, Ülo

    2016-07-01

    Fungal infections result in decreases in photosynthesis, induction of stress and signaling volatile emissions and reductions in constitutive volatile emissions, but the way different physiological processes scale with the severity of infection is poorly known. We studied the effects of infection by the obligate biotrophic fungal pathogen Melampsora larici-populina Kleb., the causal agent of poplar leaf rust disease, on photosynthetic characteristics, and constitutive isoprene and induced volatile emissions in leaves of Populus balsamifera var. suaveolens (Fisch.) Loudon. exhibiting different degrees of damage. The degree of fungal damage, quantified by the total area of chlorotic and necrotic leaf areas, varied between 0 (noninfected control) and ∼60%. The rates of all physiological processes scaled quantitatively with the degree of visual damage, but the scaling with damage severity was weaker for photosynthetic characteristics than for constitutive and induced volatile release. Over the whole range of damage severity, the net assimilation rate per area (AA) decreased 1.5-fold, dry mass per unit area 2.4-fold and constitutive isoprene emissions 5-fold, while stomatal conductance increased 1.9-fold and dark respiration rate 1.6-fold. The emissions of key stress and signaling volatiles (methanol, green leaf volatiles, monoterpenes, sesquiterpenes and methyl salicylate) were in most cases nondetectable in noninfested leaves, and increased strongly with increasing the spread of infection. The moderate reduction in AA resulted from the loss of photosynthetically active biomass, but the reduction in constitutive isoprene emissions and the increase in induced volatile emissions primarily reflected changes in the activities of corresponding biochemical pathways. Although all physiological alterations in fungal-infected leaves occurred in a stress severity-dependent manner, modifications in primary and secondary metabolic pathways scaled differently due to contrasting

  12. Characterization of a pathogenesis-related thaumatin-like protein gene TaPR5 from wheat induced by stripe rust fungus.

    Science.gov (United States)

    Wang, Xiaojie; Tang, Chunlei; Deng, Lin; Cai, Gaolei; Liu, Xinying; Liu, Bo; Han, Qingmei; Buchenauer, Heinrich; Wei, Guorong; Han, Dejun; Huang, Lili; Kang, Zhensheng

    2010-05-01

    Pathogenesis-related (PR) proteins, induced in plants in response to various biotic and abiotic stresses, have been assumed to play a role in plant defense system. Proteins of the PR5 family, also named thaumatin-like proteins (TLPs), have been detected in numerous plant species. In this research, a novel PR5 gene, designated as TaPR5, was isolated and characterized from wheat leaves (cv. Suwon 11) infected by the stripe rust pathotype CY23 (incompatible interaction) using the rapid amplification of cDNA ends (RACE). TaPR5 was predicted to encode a protein of 173 amino acids with an estimated molecular mass of 17.6 kDa and a theoretical pI of 4.64. The deduced amino acid sequence of TaPR5 showed a significant sequence similarity with PR5 and TLPs from barley and other plants and contained a putative signal peptide at the amino terminus. Southern blot analysis indicated that TaPR5 is coded by a single-copy gene. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that TaPR5 transcript is significantly induced and upregulated in the incompatible interaction while in the compatible interaction a relative low level of the transcript was detected. TaPR5 was also induced by phytohormones (SA, JA and ABA) and stress stimuli (wounding, cold temperature and high salinity). Using an assay of onion epidermal cells indicated accumulation of TaPR5 protein in the apoplast. The immunocytochemical method showed that the TaPR5 protein was detected on cell walls of wheat leaves in the incompatible interaction at markedly higher labeling density compared with the compatible interaction.

  13. Rust Converters

    Science.gov (United States)

    1987-11-01

    phosphate and a ferric tannate , respectively, forming an adherent substrate which may then be coated with a bituminous coating. The ensuing experiments...pre-corroded substrate. Phosphoric acid and tannic acid based rust con- verters chemically change the composition of the ferrous oxide to a ferric ...resistance (reverse)." Steel Structures Painting Council, Surface Preparation, Specification No. 2 (SSPC-SP2), "Hand Tool Cleaning" Tests performed on

  14. Abnormal germling development by brown rust and powdery mildew on cer barley mutants

    NARCIS (Netherlands)

    Rubiales, D.; Ramirez, M.C.; Carver, T.L.W.; Niks, R.E.

    2001-01-01

    The barley leaf rust fungus forms appressoria over host leaf stomata and penetrates via the stomatal pore. High levels of avoidance to leaf rust fungi have been described in some wild accessions of Hordeum species where a prominent wax layer on the stomata inhibits triggering of fungal appressorium

  15. Bulked fusiform rust inocula and Fr gene interactions in loblolly pine

    Science.gov (United States)

    Fikret Isik; Henry Amerson; Saul Garcia; Ross Whetten; Steve. McKeand

    2012-01-01

    Fusiform rust disease in loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm. var elliottii) pine plantations in the southern United States causes multi-million dollar annual losses. The disease is endemic to the region. The fusiform rust fungus (Cronartium quercuum sp.

  16. Resistance to white pine blister rust in Pinus flexilis and P

    Science.gov (United States)

    Anna W. Schoettle; Richard A. Sniezko; Angelia Kegley; Jerry Hill; Kelly S. Burns

    2010-01-01

    The non-native fungus Cronartium ribicola, that causes white pine blister rust (WPBR), is impacting or threatening limber pine, Pinus flexilis, and Rocky Mountain bristlecone pine, Pinus aristata. In the Southern Rockies, where the rust invasion is still expanding, we have the opportunity to be proactive and prepare the landscape for invasion. Genetic...

  17. Responding to the soybean rust epidemic in sub-Saharan Africa: A ...

    African Journals Online (AJOL)

    Soybean rust (Phakopsora pachyrhizi Sydow), a major threat to soybean production, is a new pathogen on the African continent, where it is increasingly threatening soybean production. The fungus is highly variable, and this complicates most disease management strategies. Most research on soybean rust, ...

  18. Biology and pathology of Ribes and their implications for management of white pine blister rust

    Science.gov (United States)

    P. J. Zambino

    2010-01-01

    Ribes (currants and gooseberries) are telial hosts for the introduced and invasive white pine blister rust fungus, Cronartium ribicola. Knowledge of wild and introduced Ribes helps us understand the epidemiology of blister rust on its aecial hosts, white pines, and develop disease control and management strategies. Ribes differ by species in their contribution to...

  19. Virulence diversity of Uromyces Appendiculatus in the Highlands of Guatemala

    Science.gov (United States)

    The common bean is planted throughout Guatemala, especially in the highlands of the South East, North East, and South West regions. In these regions, temperatures fluctuate between 16 y 20 °C and the average rain precipitation is about 1000 mm. These conditions are optimum for the rust disease and b...

  20. Teste de resistência ao Uromyces appendiculatus por meio da inoculação do patógeno em folhas destacadas do feijoeiro = Resistance test to Uromyces appendiculatus through pathogen inoculation in common bean detached leaves

    Directory of Open Access Journals (Sweden)

    Thiago Lívio Pessoa Oliveira de Souza

    2009-04-01

    Full Text Available É proposta uma nova metodologia para inoculação de Uromyces appendiculatus a fim de avaliar a resistência do feijoeiro à ferrugem. As linhagens Golden Gate Wax (gene Ur-6 e Ouro Negro (gene Ur-ON foram cruzadas para a obtenção de uma população F2, que foiinoculada com a raça 29-3 de U. appendiculatus. Essa raça é incompatível com Ouro Negro e compatível com Golden Gate Wax. Folhas primárias das plantas F2 foram destacadas dez dias após a semeadura e inoculadas por submersão em suspensão de inóculo. Posteriormente, cada folha foi transferida para uma placa de Petri contendo papel de filtro umedecido com água destilada, e as placas foram, então, incubadas em BOD a 20°C, em regime de 12h de luz dia-1. A umidade nointerior das placas foi mantida pela adição de 1,5 mL de água destilada em intervalos de três dias. Como controle, as folhas primárias remanescentes das plantas F2, no mesmo estágio dedesenvolvimento, foram inoculadas utilizando o método convencional de inoculação. Ambos os procedimentos de inoculação foram eficientes para avaliar a reação do feijoeiro ao U. appendiculatus. Em ambos os métodos, a análise fenotípica da população F2 confirmou anatureza monogênica dominante da resistência à ferrugem conferida pelo gene Ur-ON.A new methodology of inoculating Uromyces appendiculatusin tests aimed at evaluation of common bean resistance to rust is proposed. The common bean lines Golden Gate Wax (gene Ur-6 and Ouro Negro (gene Ur-ON were crossed to obtain a F2 population, which was inoculated with race 29-3 of U. appendiculatus. Race 29-3 is incompatible with ‘Ouro Negro’ and compatible with ‘Golden Gate Wax’. Primary leaves of ten-days-old F2 plants were detached and inoculated by immersion into an inoculum suspension. Immediatelyfollowing immersion, each F2 leaf was placed in a Petri dish containing a filter paper previously moistened with distilled water. These dishes were incubated in a BOD

  1. Impact of ectomycorrhizal colonization and rust infection on the secondary metabolism of poplar (Populus trichocarpa x deltoides).

    Science.gov (United States)

    Pfabel, Cornelia; Eckhardt, Kai-Uwe; Baum, Christel; Struck, Christine; Frey, Pascal; Weih, Martin

    2012-11-01

    Fungal colonization can significantly affect the secondary metabolism of the host plants. We tested the impact of a common below-ground symbiosis, i.e., ectomycorrhiza formation, on poplar leaf chemical components that are involved in the defence against a common disease, i.e., rust fungi, in N-deficient soil. A rust-susceptible poplar clone (Populus trichocarpa × deltoides 'Beaupré') was (a) non-associated with ectomycorrhizal fungus (EM) Hebeloma mesophaeum (Pers.) Quélet MÜN and non-infected with rust fungus Melampsora larici-populina Kleb. (isolate 98AG31), (b) associated with EM, (c) inoculated with rust fungus and (d) associated with EM and inoculated with rust fungus. Poplar leaves were analysed by photometric and mass spectrometric techniques (liquid chromatography-tandem mass spectrometry (LC-MS/MS), pyrolysis-field ionization mass spectrometry (Py-FIMS)). Both rust infection and mycorrhiza formation led to increased proportions of condensed tannins in relation to total phenolics (13% in the control, 18-19% in the fungal treatments). In contrast, salicylic acid concentration (6.8 µg g(-1) in the control) was higher only in the rust treatments (17.9 and 25.4 µg g(-1) with rust infection). The Py-FIMS analysis revealed that the rust-infected treatments were significantly separated from the non-rust-infected treatments on the basis of six flavonoids and one lipid. The relative abundance of these components, which have known functions in plant defence, was decreased after rust infection of non-mycorrhizal plants, but not in mycorrhizal plants. The results indicate that the ectomycorrhizal formation compensated the rust infection by a decrease in the flavonoid syntheses. The study provides new evidence for an interactive response of mycorrhizal colonization and infection with rust fungi in the metabolism of poplar.

  2. Sources of stem rust resistance in Ethiopian tetraploid wheat ...

    African Journals Online (AJOL)

    Stem or black rust of wheat caused by the fungus Puccinia graminis f. sp. tritici Ericks and Henn (Pgt) is an important disease on wheat worldwide. Pgt is an obligate biotroph, heteroceous in its life cycle and heterothallic in mating type. Seedlings of 41 emmer (Triticum dicoccum), 56 durum (T. durum) wheat accessions were ...

  3. White pine blister rust in the interior Mountain West

    Science.gov (United States)

    Kelly Burns; Jim Blodgett; Dave Conklin; Brian Geils; Jim Hoffman; Marcus Jackson; William Jacobi; Holly Kearns; Anna Schoettle

    2010-01-01

    White pine blister rust is an exotic, invasive disease of white, stone, and foxtail pines (also referred to as white pines or five-needle pines) in the genus Pinus and subgenus Strobus (Price and others 1998). Cronartium ribicola, the fungus that causes WPBR, requires an alternate host - currants and gooseberries in the genus Ribes and species of Pedicularis...

  4. White pine blister rust resistance research in Minnesota and Wisconsin

    Science.gov (United States)

    Andrew David; Paul Berrang; Carrie Pike

    2012-01-01

    The exotic fungus Cronartium ribicola causes the disease white pine blister rust on five-needled pines throughout North America. Although the effects of this disease are perhaps better known on pines in the western portion of the continent, the disease has also impacted regeneration and growth of eastern white pine (Pinus strobus L. ...

  5. Morphology of germlings of urediniospores and its value for the identification and classification of grass rust fungi

    NARCIS (Netherlands)

    Swertz, C.A.

    1994-01-01

    The identification and classification of grass rust fungi is often difficult since most traditionally used morphological characters are quantitative and subjective. Besides, when using the host range as a taxonomic criterion, it is important to realize that a rust fungus may have jumped to

  6. Frequency and distribution of the brown rust resistance gene Bru1 and implications for the Louisiana sugarcane breeding programme

    Science.gov (United States)

    Brown rust, caused by the fungus Puccinia melanocephala, is an important disease of sugarcane posing an increasing threat to sugarcane industries worldwide. A major gene, Bru1, has been shown to contribute a significant proportion of brown rust resistance in multiple sugarcane industries. The recent...

  7. Tracking the distribution of Puccinia psidii genotypes that cause rust disease on diverse myrtaceous trees and shrubs

    Science.gov (United States)

    Amy L. Ross-Davis; Rodrigo N. Graca; Acelino C. Alfenas; Tobin L. Peever; Jack W. Hanna; Janice Y. Uchida; Rob D. Hauff; Chris Y. Kadooka; Mee-Sook Kim; Phil G. Cannon; Shigetou Namba; Nami Minato; Sofia Simeto; Carlos A. Perez; Min B. Rayamajhi; Mauricio Moran; D. Jean Lodge; Marcela Arguedas; Rosario Medel-Ortiz; M. Armando Lopez-Ramirez; Paula Tennant; Morag Glen; Ned B. Klopfenstein

    2014-01-01

    Puccinia psidii Winter (Basidiomycota, Uredinales) is a biotrophic rust fungus that was first reported in Brazil from guava in 1884 (Psidium guajava; Winter 1884) and later from eucalypt in 1912 (Joffily 1944). Considered to be of neotropical origin, the rust has also been reported to infect diverse myrtaceous hosts elsewhere in South America, Central America, the...

  8. Screening and incorporation of rust resistance from Allium cepa into bunching onion (Allium fistulosum) via alien chromosome addition.

    Science.gov (United States)

    Wako, Tadayuki; Yamashita, Ken-ichiro; Tsukazaki, Hikaru; Ohara, Takayoshi; Kojima, Akio; Yaguchi, Shigenori; Shimazaki, Satoshi; Midorikawa, Naoko; Sakai, Takako; Yamauchi, Naoki; Shigyo, Masayoshi

    2015-04-01

    Bunching onion (Allium fistulosum L.; 2n = 16), bulb onion (Allium cepa L. Common onion group), and shallot (Allium cepa L. Aggregatum group) cultivars were inoculated with rust fungus, Puccinia allii, isolated from bunching onion. Bulb onions and shallots are highly resistant to rust, suggesting they would serve as useful resources for breeding rust resistant bunching onions. To identify the A. cepa chromosome(s) related to rust resistance, a complete set of eight A. fistulosum - shallot monosomic alien addition lines (MAALs) were inoculated with P. allii. At the seedling stage, FF+1A showed a high level of resistance in controlled-environment experiments, suggesting that the genes related to rust resistance could be located on shallot chromosome 1A. While MAAL, multi-chromosome addition line, and hypoallotriploid adult plants did not exhibit strong resistance to rust. In contrast to the high resistance of shallot, the addition line FF+1A+5A showed reproducibly high levels of rust resistance.

  9. Fine Mapping of Ur-3, a Historically Important Rust Resistance Locus in Common Bean

    Directory of Open Access Journals (Sweden)

    Oscar P. Hurtado-Gonzales

    2017-02-01

    Full Text Available Bean rust, caused by Uromyces appendiculatus, is a devastating disease of common bean (Phaseolus vulgaris in the Americas and Africa. The historically important Ur-3 gene confers resistance to many races of the highly variable bean rust pathogen that overcome other rust resistance genes. Existing molecular markers tagging Ur-3 for use in marker-assisted selection produce false results. Here, we describe the fine mapping of the Ur-3 locus for the development of highly accurate markers linked to Ur-3. An F2 population from the cross Pinto 114 (susceptible × Aurora (resistant with Ur-3 was evaluated for its reaction to four different races of U. appendiculatus. A bulked segregant analysis using the SNP chip BARCBEAN6K_3 placed the approximate location of Ur-3 in the lower arm of chromosome Pv11. Specific SSR and SNP markers and haplotype analysis of 18 sequenced bean varieties positioned Ur-3 in a 46.5 kb genomic region from 46.96 to 47.01 Mb on Pv11. We discovered in this region the SS68 KASP marker that was tightly linked to Ur-3. Validation of SS68 on a panel of 130 diverse common bean cultivars containing all known rust resistance genes revealed that SS68 was highly accurate and produced no false results. The SS68 marker will be of great value in pyramiding Ur-3 with other rust resistance genes. It will also significantly reduce time and labor associated with the current phenotypic detection of Ur-3. This is the first utilization of fine mapping to discover markers linked to rust resistance in common bean.

  10. Fine Mapping of Ur-3, a Historically Important Rust Resistance Locus in Common Bean.

    Science.gov (United States)

    Hurtado-Gonzales, Oscar P; Valentini, Giseli; Gilio, Thiago A S; Martins, Alexandre M; Song, Qijian; Pastor-Corrales, Marcial A

    2017-02-09

    Bean rust, caused by Uromyces appendiculatus, is a devastating disease of common bean (Phaseolus vulgaris) in the Americas and Africa. The historically important Ur-3 gene confers resistance to many races of the highly variable bean rust pathogen that overcome other rust resistance genes. Existing molecular markers tagging Ur-3 for use in marker-assisted selection produce false results. Here, we describe the fine mapping of the Ur-3 locus for the development of highly accurate markers linked to Ur-3 An F2 population from the cross Pinto 114 (susceptible) × Aurora (resistant with Ur-3) was evaluated for its reaction to four different races of U. appendiculatus A bulked segregant analysis using the SNP chip BARCBEAN6K_3 placed the approximate location of Ur-3 in the lower arm of chromosome Pv11. Specific SSR and SNP markers and haplotype analysis of 18 sequenced bean varieties positioned Ur-3 in a 46.5 kb genomic region from 46.96 to 47.01 Mb on Pv11. We discovered in this region the SS68 KASP marker that was tightly linked to Ur-3 Validation of SS68 on a panel of 130 diverse common bean cultivars containing all known rust resistance genes revealed that SS68 was highly accurate and produced no false results. The SS68 marker will be of great value in pyramiding Ur-3 with other rust resistance genes. It will also significantly reduce time and labor associated with the current phenotypic detection of Ur-3 This is the first utilization of fine mapping to discover markers linked to rust resistance in common bean. Copyright © 2017 Hurtado-Gonzales et al.

  11. Wheat Rust Toolbox Related to New Initiatives on Yellow Rust

    DEFF Research Database (Denmark)

    Hansen, Jens Grønbech; Lassen, Poul

    A wheat rust toolbox was developed in the frame of the Borlaug Global Rust Initiative (BGRI) to support the early warning and monitoring of stem rust on a global scale. The toolbox consists of a number of databases and web applications for data management, quality control, dissemination and display......-report/en/). The Wheat rust toolbox is one of several International research platforms hosted by Aarhus University, and it uses the same ICT framework and databases as EuroWheat (www.eurowheat.org) and EuroBlight (www.EuroBlight.net). The Wheat Rust Toolbox will also serve the Global Rust Reference Centre (GRRC) as well...... as several other Institutions and information platforms in the Durable Rust Resistance in Wheat project under the BGRI. From the outset the databases and information tools were developed to handle all three rust types. The EuroWheat platform already contains data on yellow rust pathotypes from Europe (1993...

  12. Derivation of host and pathogen genotypes in the fusiform rust pathosystem on slash pine using a complimentary genetics model and diallel data

    Science.gov (United States)

    H.E. Stelzel; Robert L. Doudrick; Thomas L. Kubisiak

    1997-01-01

    Seedlings from 20, full-sib families five-parent slash pine diallel were inoculated using two, single urediniospore-derived cultures of the fusiform rust fungus on two different dates during the 1994 growing season. Presence or absence of fusiform rust galls was recorded for each inoculated seedling at nine months post-inoculation and percent infection levels for each...

  13. Climate change impacts on coffee rust disease

    Science.gov (United States)

    Alfonsi, W. M. V.; Koga-Vicente, A.; Pinto, H. S.; Alfonsi, E. L., Sr.; Coltri, P. P.; Zullo, J., Jr.; Patricio, F. R.; Avila, A. M. H. D.; Gonçalves, R. R. D. V.

    2016-12-01

    Changes in climate conditions and in extreme weather events may affect the food security due to impacts in agricultural production. Despite several researches have been assessed the impacts of extremes in yield crops in climate change scenarios, there is the need to consider the effects in pests and diseases which increase losses in the sector. Coffee Arabica is an important commodity in world and plays a key role in Brazilian agricultural exports. Although the coffee crop has a world highlight, its yield is affected by several factors abiotic or biotic. The weather as well pests and diseases directly influence the development and coffee crop yield. These problems may cause serious damage with significant economic impacts. The coffee rust, caused by the fungus Hemileia vastarix,is among the diseases of greatest impact for the crop. The disease emerged in Brazil in the 70s and is widely spread in all producing regions of coffee in Brazil, and in the world. Regions with favorable weather conditions for the pathogen may exhibit losses ranging from 30% to 50% of the total grain production. The evaluation of extreme weather events of coffee rust disease in futures scenarios was carried out using the climatic data from CMIP5 models, data field of coffee rust disease incidence and, incubation period simulation data for Brazilian municipalities. Two Regional Climate Models were selected, Eta-HadGEM2-ES and Eta-MIROC5, and the Representative Concentration Pathways 8.5 w/m2 was adopted. The outcomes pointed out that in these scenarios the period of incubation tends to decrease affecting the coffee rust disease incidence, which tends to increase. Nevertheless, the changing in average trends tends to benefit the reproduction of the pathogen. Once the temperature threshold for the disease reaches the adverse conditions it may be unfavorable for the incidence.

  14. Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen

    Directory of Open Access Journals (Sweden)

    Cheng Yulin

    2012-06-01

    Full Text Available Abstract Background Non-host resistance (NHR confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens. Results In this study, the basis of NHR in broad bean (Vicia faba L. against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst, was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection. Conclusions The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal

  15. An analysis of the risk of introduction of additional strains of the rust puccinia psidii Winter ('Ohi'a Rust) to Hawai'i

    Science.gov (United States)

    Loope, Lloyd; La Rosa, Anne Marie

    2010-01-01

    In April 2005, the rust fungus Puccinia psidii (most widely known as guava rust or eucalyptus rust) was found in Hawai'i. This was the first time this rust had been found outside the Neotropics (broadly-defined, including subtropical Florida, where the rust first established in the 1970s). First detected on a nursery-grown 'ohi'a plant, it became known as ''ohi'a rust'in Hawai'i. The rust spread rapidly and by August 2005 had been found throughout the main Hawaiian Islands. The rust probably reached Hawai'i via the live plant trade or via the foliage trade. In Hawai'i, the rust has infected three native plant species and at least eight non-native species. Effects have been substantial on the endangered endemic plant Eugenia koolauensis and the introduced rose apple, Syzygium jambos. Billions of yellow, asexual urediniospores are produced on rose apple, but a complete life cycle (involving sexual reproduction) has not yet been observed. The rust is autoecious (no alternate host known) on Myrtaceae. The strain introduced into Hawai'i is found sparingly on 'ohi'a (Metrosideros polymorpha), the dominant tree of Hawai'i's forests, with sporadic damage detected to date. The introduction of a rust strain that causes widespread damage to 'ohi'a would be catastrophic for Hawai'i's native biodiversity. Most imports of material potentially contaminated with rust are shipped to Hawai'i from Florida and California (from which P. psidii was reported in late 2005 by Mellano, 2006). Florida is known to have multiple strains. The identity of the strain or strains in California is unclear, but one of them is known to infect myrtle, Myrtus communis, a species commonly imported into Hawai'i. It is important to ecosystem conservation and commercial forestry that additional rust strains or genotypes be prevented from establishing in Hawai'i. The purpose of this analysis of risk is to evaluate the need for an interim rule by the Hawai'i Department of Agriculture to regulate plant

  16. URS Brava – a new oat cultivar with partial resistance to crown rust

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Federizzi

    2015-08-01

    Full Text Available The cultivar URS Brava, obtained from a simple cross between the line ‘UFRGS 995078-2’ and the cultivar ‘URS 21’, shows high grain yield and stability, high grain quality, desirable agronomical traits and partial resistance to crown rust, caused by the fungus Puccinia coronata f. sp. avenae.

  17. Label-Free Detection of Soybean Rust Spores using Photonic Crystal Biosensors

    Science.gov (United States)

    Soybean rust, caused by the fungus Phakopsora pachyrhizi, is one of the most devastating foliar diseases affecting soybeans grown worldwide. The disease was reported for the first time in the United States in 2004. Early spore detection, prior to the appearance of visible symptoms, is critical to ef...

  18. Interrelations between citrus rust mite, Hirsutella thompsonii and greasy spot on citrus in Surinam

    NARCIS (Netherlands)

    Brussel, van E.W.

    1975-01-01

    Counts of citrus rust mite (Phyllocoptruta oleivora (Ashm.)) on leaves and fruit of citrus rose to a peak in the two dry seasons, the build up taking 4-5 weeks. It then decreased partly through infection by the entomogenous fungus

  19. Distribution of Ribes, an alternate host of white pine blister rust, in Colorado and Wyoming

    Science.gov (United States)

    Holly S. J. Kearns; William R. Jacobi; Kelly S. Burns; Brian W. Geils

    2008-01-01

    Ribes (currants and gooseberries) are alternate hosts for Cronartium ribicola, the invasive fungus that causes blister rust of white pines (Pinus, subgenus Strobus) in the Rocky Mountain region of Colorado and Wyoming. The location, species, and density of Ribes can affect...

  20. REVIEW - Advances on molecular studies of the interaction soybean - Asian rust

    Directory of Open Access Journals (Sweden)

    Aguida Maria Alves Pereira Morales

    2012-01-01

    Full Text Available Effective management practices are essential for controlling rust outbreaks. The main control methodused is the application of fungicides, which increases substantially the cost of production and is harmful to theenvironment. Prevention is still the best way to avoid more significant losses in soybean yields. Alternatives,such as planting resistant varieties to the fungus, are also important. The use of resistant or tolerant varietiesis the most promising method for controlling Asian soybean rust. Recently, five dominant genes resistant to soybean rust were described: Rpp1, Rpp2, Rpp3, Rpp4 and Rpp5. However, little is known about the molecular interaction among soybean plant and soybean rust and on the molecular pathway triggered by pathogen recognition. Understanding the molecular mechanisms involved in defense responses is of primary importance for planning strategies to control stress and, consequently, to increase plant adaptation to limiting conditions

  1. SCAR markers linked to the common bean rust resistance gene Ur-13.

    Science.gov (United States)

    Mienie, C M S; Liebenberg, M M; Pretorius, Z A; Miklas, P N

    2005-09-01

    Rust in common bean (Phaseolus vulgaris L.) is caused by Uromyces appendiculatus Pers.:Pers. (Unger) which exhibits a high level of pathogenic diversity. Resistance to this disease is conditioned by a considerable number of genes. Pyramiding resistance genes is desirable and could be simplified by the use of molecular markers closely linked to the genes. The resistance gene Ur-13, present in the South African large seeded cultivar Kranskop, has been used extensively in the local breeding program. The purpose of this study was the development of a molecular marker linked to Ur-13. An F(2) population derived from a cross between Kranskop and a susceptible (South African) cultivar Bonus was used in combination with bulked segregant analysis utilizing the amplified fragment length polymorphism (AFLP) technique. Seven AFLP fragments linked significantly to the rust resistance and five were successfully converted to sequence characterized amplified region (SCAR) markers. The co-dominant SCAR markers derived from a 405 bp EAACMACC fragment, KB 126, was located 1.6 cM from the gene. Two additional SCAR markers and one cleaved amplified polymorphic sequence marker were located further from the gene. The gene was mapped to linkage group B8 on the BAT 93/Jalo EEP 558 core map (chromosome 3).

  2. A novel fungal hyperparasite of Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust.

    Directory of Open Access Journals (Sweden)

    Gangming Zhan

    Full Text Available Puccinia striiformis f. sp. tritici (Pst, the causal fungus of wheat stripe rust, was previously reported to be infected by Lecanicillium lecanii, Microdochium nivale and Typhula idahoensis. Here, we report a novel hyperparasite on Pst. This hyperparasitic fungus was identified as Cladosporium cladosporioides (Fresen. GA de Vries based on morphological characteristics observed by light and scanning electron microscopy together with molecular data. The hyperparasite reduced the production and viability of urediniospores and, therefore, could potentially be used for biological control of wheat stripe rust.

  3. Phylogenetic studies in Ravenelia esculenta and related rust fungi.

    Science.gov (United States)

    Gandhe, K R; Kuvalekar, Aniket

    2007-09-01

    Ravenelia esculenta Naras. and Thium. is a rust fungus, which infects mostly thorns, inflorescences, flowers and fruits of Acacia eburnea Willd. Aecial stages of the rust produce hypertrophy in infected parts. DNA of the rust fungus was isolated from aeciospores by 'freeze thaw' method. 18S rDNA was amplified and sequenced by automated DNA sequencer. BLAST of the sequence at NCBI retrieved 96 sequences producing significant alignments. Multiple sequence alignment of these sequences was done by ClustalW. Phylogenetic analysis was done by using MEGA 3.1. UPGMA Minimum Evolution tree with bootstrap value of 1000 replicates was constructed using these sequences. From phylogenetic tree it is observed that Ravenelia esculenta and the genus Gymnosporangium share a common ancestry, though Ravenelia esculenta is autoecious on angiosperm and the genus Gymnosporangium is heteroecious with pycnia, aecia on angiosperm and uredia, telia on gymnosperm. Two major clades are recognized which are based on the nature of aecial host (gymnosperm or angiosperm). These clades were also showing shift from pteridophytes to angiosperms as telial hosts. The tree can be interpreted in the other way also where there is separation of 14 families of Uredinales depending upon nature of teliospores, nature of aeciospores and structure of pycnia. These studies determine the phylogenetic position of Ravenelia esculenta among other rust fungi besides broad separation of Uredinales into two clades. These studies also show that there is phylogenetic correlation between molecular and morphological data. This is first report of DNA sequencing and phylogenetic positioning in genus Ravenelia from India.

  4. Nail Fungus

    Science.gov (United States)

    ... cause is a type of fungus called dermatophyte. Yeast and molds also can cause nail infections. Fungal ... more years of exposure to fungi and slower growing nails Sweating heavily Having a history of athlete's ...

  5. Identification and potential use of a molecular marker for rust resistance in common bean.

    Science.gov (United States)

    Miklas, P N; Stavely, J R; Kelly, J D

    1993-02-01

    The Up 2 gene of common bean (Phaseolus Vulgaris L.) is an important source of dominant genetic resistance to the bean rust pathogen [Uromyces appendiculatus (Pers. ex Pers.) Unger var 'appendiculatus' [syn U. Phaseoli (Reben) Wint.]. Up 2 in combination with other rust resistance genes may be used to obtain potentially stable genetic resistance. It is difficult, however, to combine rust resistance genes effective against a single race due to epistatic interactions that frequently occur between them. A strategy that employed bulked DNA samples formed separately from the DNA of three BC6F2 individuals with Up 2 and three without Up 2 as contrasting near-isogenic lines (NILs) was used to identify random amplified polymorphic DNA fragments (RAPDs) tightly linked to the Up 2 locus. Only 1 of 931 fragments amplified by 167 10-mer primers of arbitrary sequence in the polymerase chain reaction (PCR) was polymorphic. The RAPD marker (OA141100) amplified by the 5'-TCTGTGCTGG-3' primer was repeatable and its presence and absence easy to score. No recombination was observed between OA141100 and the dominant Up 2 allele within a segregating BC6F2 population of 84 individuals. This result suggests that OA141100 and Up 2 are tightly linked. Andean and Mesoamerican bean germ plasm, with and without the Up 2 allele, were assayed for the presence of OA141100. Apparently, the marker is of Andean origin because all Andean lines, with or without the Up 2 allele, contained the marker, and the marker was absent in all Mesoamerican germ plasm except the lines to which Up-2 had been purposely transferred. These results suggest that OA141100 will be most useful for pyramiding Up 2 with other rust resistance genes into germ plasm of Mesoamerican origin where the marker does not traditionally exist. The use of bulked DNA samples may have concentrated resources toward the identification of RAPDs that were tightly linked to the target locus. Marker-based selection may provide an alternative to

  6. Ricoseius loxocheles, a phytoseiid mite that feeds on coffee leaf rust.

    Science.gov (United States)

    Oliveira, Cleber M; Ferreira, João A M; Oliveira, Rafael M; Santos, Francisco O; Pallini, Angelo

    2014-10-01

    One of the most important diseases of coffee plants is the coffee leaf rust fungus Hemileia vastatrix Berkeley and Broome (Uredinales). It can cause 30 % yield loss in some varieties of Coffea arabica (L.). Besides fungus, the coffee plants are attacked by phytophagous mites. The most common species is the coffee red mite, Oligonychus ilicis McGregor (Acari: Tetranychidae). Predatory mites of the Phytoseiidae family are well-known for their potential to control herbivorous mites and insects, but they can also develop and reproduce on various other food sources, such as plant pathogenic fungi. In a field survey, we found Ricoseius loxocheles (De Leon) (Acari: Phytoseiidae) on the necrotic areas caused by the coffee leaf rust fungus during the reproductive phase of the pathogen. We therefore assessed the development, survivorship and reproduction of R. loxocheles feeding on coffee leaf rust fungus and measured predation and oviposition of this phytoseiid having coffee red mite as prey under laboratory conditions. The mite fed, survived, developed and reproduced successfully on this pathogen but it was not able to prey on O. ilicis. Survival and oviposition with only prey were the same as without food. This phytoseiid mite does not really use O. ilicis as food. It is suggested that R. loxocheles is one phytoseiid that uses fungi as a main food source.

  7. QTLs for resistance to the false brome rust Puccinia brachypodii in the model grass Brachypodium distachyon L.

    NARCIS (Netherlands)

    Barbieri, M.; Marcel, T.C.; Niks, R.E.; Francia, E.; Pasquariello, M.; Mazzamurro, V.; Garvin, D.F.; Pecchioni, N.

    2012-01-01

    The potential of the model grass Brachypodium distachyon L. (Brachypodium) for studying grass–pathogen interactions is still underexploited. We aimed to identify genomic regions in Brachypodium associated with quantitative resistance to the false brome rust fungus Puccinia brachypodii. The inbred

  8. Tandem selection for fusiform rust sisease resistance to develop a clonal elite breeding population of loblolly pine

    Science.gov (United States)

    Steve McKeand; Saul Garcia; Josh Steiger; Jim Grissom; Ross Whetten; Fikret. Isik

    2012-01-01

    The elite breeding populations of loblolly pine (Pinus taeda L.) in the North Carolina State University Cooperative Tree Improvement Program are intensively managed for short-term genetic gain. Fusiform rust disease, caused by the fungus Cronartium quercuum f. sp. fusiforme, is the most economically...

  9. Rust disease of eucalypts, caused by Puccinia psidii, did not originate via host jump from guava in Brazil

    Science.gov (United States)

    Rodrigo N. Graca; Amy L. Ross-Davis; Ned B. Klopfenstein; Mee-Sook Kim; Tobin L. Peever; Phil G. Cannon; Cristina P. Aun; Eduardo G. Mizubuti; Acelino C. Alfenas

    2013-01-01

    The rust fungus, Puccinia psidii, is a devastating pathogen of introduced eucalypts (Eucalyptus spp.) in Brazil where it was first observed in 1912. This pathogen is hypothesized to be endemic to South and Central America and to have first infected eucalypts via a host jump from native guava (Psidium guajava). Ten microsatellite markers were used to genotype 148 P....

  10. Non-Ribes alternate hosts of white pine blister rust: What this discovery means to whitebark pine

    Science.gov (United States)

    Paul J. Zambino; Bryce A. Richardson; Geral I. McDonald; Ned B. Klopfenstein; Mee-Sook. Kim

    2006-01-01

    From early to present-day outbreaks, white pine blister rust caused by the fungus Cronartium ribicola, in combination with mountain pine beetle outbreaks and fire exclusion has caused ecosystem-wide effects for all five-needled pines (McDonald and Hoff 2001). To be successful, efforts to restore whitebark pine will require sound management decisions that incorporate an...

  11. Anti-rust product poisoning

    Science.gov (United States)

    ... agents Hydrocarbons Hydrochloric acid Nitrites Oxalic acid Phosphoric acid ... red blood cells) Too much or too little acid in the blood, which ... anti-rust products come from inhaling the substance. LUNGS AND ...

  12. Durability of resistance to rust in sunflower: Implications for resistance breeding

    Directory of Open Access Journals (Sweden)

    Llamas José María

    2010-01-01

    Full Text Available Sunflower rust is caused by Puccinia helianthi Schw. and is an important disease in Argentina, Australia, Canada, Egypt, Israel, Turkey, USA and the former USSR. Sunflower rust is a macrocyclic, heterothallic and autoecious fungus, surviving mainly in plant debris in soil in the form of teliospores. New races of P. helianthi are continuously evolving and overcoming resistance genes, resulting in a continuous threat for the crop. The deployment of hybrids with simple resistances has exacerbated this problem. Combination of the appropriate R-genes could result in a resistance more difficult to overcome. The identification and characterization of new durable sources of sunflower rust resistance is a high priority for both researchers and industry. There is a possibility of breeding for high coumarin content to improve resistance at early stages of fungal development.

  13. REVIEW - Advances on molecular studies of the interaction soybean - Asian rust

    OpenAIRE

    Aguida Maria Alves Pereira Morales; Aluízio Borém; Graham, Michelle A; Ricardo Vilela Abdelnoor

    2012-01-01

    Effective management practices are essential for controlling rust outbreaks. The main control methodused is the application of fungicides, which increases substantially the cost of production and is harmful to theenvironment. Prevention is still the best way to avoid more significant losses in soybean yields. Alternatives,such as planting resistant varieties to the fungus, are also important. The use of resistant or tolerant varietiesis the most promising method for controlling Asian soybean ...

  14. Quantification and Gene Expression Analysis of Histone Deacetylases in Common Bean during Rust Fungal Inoculation.

    Science.gov (United States)

    Melmaiee, Kalpalatha; Kalavacharla, Venu Kal; Brown, Adrianne; Todd, Antonette; Thurston, Yaqoob; Elavarthi, Sathya

    2015-01-01

    Histone deacetylases (HDACs) play an important role in plant growth, development, and defense processes and are one of the primary causes of epigenetic modifications in a genome. There was only one study reported on epigenetic modifications of the important legume crop, common bean, and its interaction with the fungal rust pathogen Uromyces appendiculatus prior to this project. We measured the total active HDACs levels in leaf tissues and observed expression patterns for the selected HDAC genes at 0, 12, and 84 hours after inoculation in mock inoculated and inoculated plants. Colorimetric analysis showed that the total amount of HDACs present in the leaf tissue decreased at 12 hours in inoculated plants compared to mock inoculated control plants. Gene expression analyses indicated that the expression pattern of gene PvSRT1 is similar to the trend of total active HDACs in this time course experiment. Gene PvHDA6 showed increased expression in the inoculated plants during the time points measured. This is one of the first attempts to study expression levels of HDACs in economically important legumes in the context of plant pathogen interactions. Findings from our study will be helpful to understand trends of total active HDACs and expression patterns of these genes under study during biotic stress.

  15. Quantification and Gene Expression Analysis of Histone Deacetylases in Common Bean during Rust Fungal Inoculation

    Directory of Open Access Journals (Sweden)

    Kalpalatha Melmaiee

    2015-01-01

    Full Text Available Histone deacetylases (HDACs play an important role in plant growth, development, and defense processes and are one of the primary causes of epigenetic modifications in a genome. There was only one study reported on epigenetic modifications of the important legume crop, common bean, and its interaction with the fungal rust pathogen Uromyces appendiculatus prior to this project. We measured the total active HDACs levels in leaf tissues and observed expression patterns for the selected HDAC genes at 0, 12, and 84 hours after inoculation in mock inoculated and inoculated plants. Colorimetric analysis showed that the total amount of HDACs present in the leaf tissue decreased at 12 hours in inoculated plants compared to mock inoculated control plants. Gene expression analyses indicated that the expression pattern of gene PvSRT1 is similar to the trend of total active HDACs in this time course experiment. Gene PvHDA6 showed increased expression in the inoculated plants during the time points measured. This is one of the first attempts to study expression levels of HDACs in economically important legumes in the context of plant pathogen interactions. Findings from our study will be helpful to understand trends of total active HDACs and expression patterns of these genes under study during biotic stress.

  16. Identification of RAPD markers linked to a major rust resistance gene block in common bean.

    Science.gov (United States)

    Haley, S D; Miklas, P N; Stavely, J R; Byrum, J; Kelly, J D

    1993-05-01

    Rust in bean (Phaseolus vulgaris L.), caused byUromyces appendiculatus (Pers.) Unger var.appendiculatus [ =U. phaseoli (Reben) Wint.], is a major disease problem and production constraint in many parts of the world. The predominant form of genetic control of the pathogen is a series of major genes which necessitate the development of efficient selection strategies. Our objective was focused on the identification of RAPD (random amplified polymorphic DNA) markers linked to a major bean rust resistance gene block enabling marker-based selection and facilitating resistance gene pyramiding into susceptible bean germplasm. Using pooled DNA samples of genotyped individuals from two segregating populations, we identified two RAPD markers linked to the gene block of interest. One such RAPD, OF10970 (generated by a 5'-GGAAGCTTGG-3' decamer), was found to be closely linked (2.15±1.50 centi Morgans) in coupling with the resistance gene block. The other identified RAPD, OI19460 (generated by a 5'-AATGCGGGAG-3' decamer), was shown to be more tightly linked (also in coupling) than OF10970 as no recombinants were detected among 97 BC6F2 segregating individuals in the mapping population. Analysis of a collection of resistant and susceptible cultivars and experimental lines, of both Mesoamerican and Andean origin, revealed that: (1) recombination between OF10970 and the gene block has occurred as evidenced by the presence of the DNA fragment in several susceptible genotypes, (2) recombination between OI19460 and the gene block has also occurred indicating that the marker is not located within the gene block itself, and (3) marker-facilitated selection using these RAPD markers, and another previously identified, will enable gene pyramiding in Andean germplasm and certain Mesoamerican bean races in which the resistance gene block does not traditionally exist. Observations of variable recombination among Mesoamerican bean races suggested suppression of recombination between

  17. A summary of information on the rust Puccinia psidii Winter (guava rust) with emphasis on means to prevent introduction of additional strains to Hawaii

    Science.gov (United States)

    Loope, Lloyd

    2010-01-01

    The neotropical rust fungus Puccinia psidii(P. psidii) was originally described from the host common guava in its native Brazil but has been found since on hosts throughout the myrtle family (Myrtaceae), including a dramatic host jump to nonnative Eucalyptus plantations. Most rust fungi are able to live only on a very narrow range of host species. P. psidii is unusual both for having a broad host range and for the intensity of its damage to susceptible young growth. This rust first got a foothold in the United States in Florida more than three decades ago. The U.S. Department of Agriculture (USDA) has since considered it a nonactionable, nonreportable pest. Hawaii and Florida are the only two states with native species in the myrtle family. Over a period of 30 years, this rust has done little damage to any of the scattered native Myrtaceae in Florida, although the host range of the rust has gradually grown to about 30 mostly nonnative species in the family, apparently because of increasing genetic variety of the rust by repeated introductions. However, Florida’s native Myrtaceae are among the roughly 1,100 neotropical species that are largely resistant to P. psidii. The 3,000 species of non-neotropical Myrtaceae of the Pacific, Australia, Asia, and Africa are expected to prove much more vulnerable to P. psidii. Little is known about the genetics or genetic strains of P. psidii, although existing literature shows that there are numerous strains that have differential ability to infect suites of host plants.

  18. De novo assembly and phasing of dikaryotic genomes from two isolates of Puccinia coronata f. sp. avenae, the causal agent of oat crown rust

    Science.gov (United States)

    Oat crown rust, caused by the fungus Puccinia coronata f. sp. avenae (Pca), is a devastating disease that impacts worldwide oat production. For much of its life cycle Pca is dikaryotic with two separate haploid nuclei that may vary in virulence genotypes, which highlights the importance of understan...

  19. Strategies for Wheat Stripe Rust Pathogenicity Identified by Transcriptome Sequencing.

    Directory of Open Access Journals (Sweden)

    Diana P Garnica

    Full Text Available Stripe rust caused by the fungus Puccinia striiformis f.sp. tritici (Pst is a major constraint to wheat production worldwide. The molecular events that underlie Pst pathogenicity are largely unknown. Like all rusts, Pst creates a specialized cellular structure within host cells called the haustorium to obtain nutrients from wheat, and to secrete pathogenicity factors called effector proteins. We purified Pst haustoria and used next-generation sequencing platforms to assemble the haustorial transcriptome as well as the transcriptome of germinated spores. 12,282 transcripts were assembled from 454-pyrosequencing data and used as reference for digital gene expression analysis to compare the germinated uredinospores and haustoria transcriptomes based on Illumina RNAseq data. More than 400 genes encoding secreted proteins which constitute candidate effectors were identified from the haustorial transcriptome, with two thirds of these up-regulated in this tissue compared to germinated spores. RT-PCR analysis confirmed the expression patterns of 94 effector candidates. The analysis also revealed that spores rely mainly on stored energy reserves for growth and development, while haustoria take up host nutrients for massive energy production for biosynthetic pathways and the ultimate production of spores. Together, these studies substantially increase our knowledge of potential Pst effectors and provide new insights into the pathogenic strategies of this important organism.

  20. Allelic variation at loci controlling stripe rust resistance in spring wheat

    Indian Academy of Sciences (India)

    2014-08-20

    Aug 20, 2014 ... Wheat (Triticum aestivum L.) rusts have been one of the main yield limiting factors in wheat cultivation throughout the world. Three kinds of rust diseases that attack wheat crop are leaf (brown) rust, stripe (yellow) rust and stem (black) rust. Leaf rust is caused by Puccinia triticina f.sp. tritici; stripe rust is ...

  1. Crg, a gene required for Ur-3-mediated rust resistance in common bean, maps to a resistance gene analog cluster.

    Science.gov (United States)

    Kalavacharia, V; Stavely, J R; Myers, J R; McClean, P E

    2000-11-01

    Race-specific resistance to the bean rust pathogen (Uromyces appendiculatus) is provided by a number of loci in common bean (Phaseolus vulgaris). The Ur-3 locus controls hypersensitive resistance (HR) to 44 of the 89 races curated in the United States. To better understand resistance mediated by this locus, we developed new genetic material for analysis. We developed a population of mutagenized seed of cv. Sierra (genotype = Ur-3 ur-4 ur-6) that was screened with a bean rust race that is normally incompatible (HR response) on Ur-3 genotypes. We discovered two mutants of common bean, crg and ur3-delta3, in which uredinia formed on leaves (a compatible interaction) following infection. The F1 generation from a cross of these two mutants expressed the HR response, and the F2 generation segregated in a ratio of 9:7 (HR/uredinia formation). Therefore, the two genes are unlinked. Further genetic analysis determined that the mutation in ur3-delta3 was in the Ur-3 locus, and the mutation in crg was in a newly discovered gene given the symbol Crg (Complements resistance gene). Each mutation was inherited in a recessive manner. Unlike ur3-delta3, crg expressed reduced compatibility to bean rust races 49 and 47 that are normally fully compatible on genotypes, such as Sierra, that are homozygous recessive at the Ur-4 and Ur-6 loci. This suggests a gene mutated in crg is normally a positive compatibility factor for the bean-bean rust interaction. Polymerase chain reaction analysis of crg with primers to common bean resistance gene analogs (RGA) that contain a nucleotide-binding site sequence similar to those found in a number of plant disease resistance genes revealed that crg is missing the SB1 RGA, but not the linked SB3 and SB5 RGAs. Genetic analyses revealed that Crg cosegregates with the SB1 RGA. These results demonstrate that Crg is located near a RGA cluster in the common bean genome.

  2. Rust-Bio: a fast and safe bioinformatics library

    NARCIS (Netherlands)

    J. Köster (Johannes)

    2015-01-01

    textabstractWe present Rust-Bio, the first general purpose bioinformatics library for the innovative Rust programming language. Rust-Bio leverages the unique combination of speed, memory safety and high-level syntax offered by Rust to provide a fast and safe set of bioinformatics algorithms and data

  3. [Influence of salicylic and succinic acids on the cytophysiological reactions of wheat infected by brown rust].

    Science.gov (United States)

    Plotnikova, L Ia; Shtubeĭ, T Iu

    2009-01-01

    The influence of the salicylic and succinic acids on the cytophysiological reactions of the plants and cellular structures of the fungus were investigated using the model of common wheat Triticum aestivum L. infected by brown rust. The experiments were performed on seedlings of the isogenic line of var. Thatcher with resistant gene Lr19. The salicylic and succinic acids accelerated and enhanced to a different extent the generation of active oxygen species and synthesis of callose and phenylpropanoids by the plant cells contacting with cellular structures of avirulent and virulent fungal clones.

  4. Rust in Plumeria spp. (Apocynaceae in the State of Mato Grosso do Sul, Brazil.

    Directory of Open Access Journals (Sweden)

    Cassia de Carvalho

    2014-11-01

    Full Text Available Frangipani (Plumeria spp. is a plant widely used in urban ornamentation, due to its hardiness, easy handling and exuberance of its flowers. Plumeria spp. Leaves were collected in Dourados, MS, Brazil, with typical symptoms and signs of the presence of rust: powdery yellowish uredinias in the abaxial and chlorotic and necrotic spots on the adaxial surface of the leaves, sometimes resulting in leaf abscission. The present study aims to record the occurrence of the disease in the State of Mato Grosso do Sul. Microscopic observations and measurements of uredinospores and teliospores confirmed that the fungus infecting plants was Coleosporium plumeriae.

  5. Molecular and genetic study of wheat rusts

    African Journals Online (AJOL)

    Nicholas Le Maitre

    The effect of selection can be reduced by several methods. ... sition of the current and future rust population. In order to ... pathogen population structure, population genetic studies ..... The lack of diversity is probably due to reasons simi-.

  6. substitution line for resistance to stripe rust

    Indian Academy of Sciences (India)

    2011-08-19

    2D) substitution line for resistance to stripe rust. MENGPING LEI, GUANGRONG LI, SUFEN ZHANG, CHENG LIU and ZUJUN YANG. ∗. School of Life Science and Technology, University of Electronic Science and Technology ...

  7. Een oase van rust op de boerderij

    NARCIS (Netherlands)

    Noorduyn, L.

    2010-01-01

    Rust is wat consumenten zoeken op een boerderij. Of ze er nou producten kopen of gaan boerengolfen. Dat komt naar voren uit onderzoek van Wageningen UR naar de beleving van consumenten die een boerderij bezoeken

  8. Occurrence of Rust on Peucedanum japonicum Caused by Puccinia jogashimensis in Korea

    Directory of Open Access Journals (Sweden)

    Sug-Ju Ko

    2015-12-01

    Full Text Available During July to November 2014, severe rust infection was consistently found on Peucedanum japonicum growing farm in Yeosu, Korea. The rust was observed mainly on lower leaf surfaces. Symptoms of typical plants included yellow-orange rust pustules were observed on the petiole and leaf surface with small yellowish to chlorotic lesions on the upper surface. No symptom was observed on flowers. Uredinia were occurred amphigenous on leaf surface, and occasionally caulicolous, scattered or loosely aggregate, rounded to oblong, 0.4 to 4 mm in diameter, covered by epidermis, then naked, surrounded by ruptured epidermis, pulverulent, and brown. Urediniospores were ovate-ellipsoid, ellipsoid or subglobose, light brown, 20 to 45 ×15 to 35 µm, walls 2 to 4 µm thick. The resulting sequences were deposited in GenBank with accession No. KT778808, KT778809, and KT778810, respectively. Since this was the first accession of 28S sequence Puccinia jogashimensis, there was no exact match in GenBank nucleotide database. On the basis of the morphological characteristics and phylogenetic analyses of 28S rDNA, the fungus was identified as P. jogashimensis. To our knowledge, this is the first confirmed report on the occurrence of P. jogashimensis on P. japonicum in Korea.

  9. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    PUNEET INDER TOOR

    Abstract. A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcross- recombinant inbred line (BC-RIL) population derived from the cross of a ...

  10. 77 FR 65840 - Chrysanthemum White Rust Regulatory Status and Restrictions

    Science.gov (United States)

    2012-10-31

    ... Chrysanthemum White Rust Regulatory Status and Restrictions AGENCY: Animal and Plant Health Inspection Service... whether and how we should amend our process for responding to domestic chrysanthemum white rust (CWR... chrysanthemum white rust (CWR) outbreaks and the importation of plant material that is a host of CWR. CWR is an...

  11. Aspects of durable resistance in wheat to yellow rust

    NARCIS (Netherlands)

    Danial, D.L.

    1994-01-01

    In Kenya, the number of virulence factors of the yellow rust populations showed a considerable increase and a wide variability. Selecting for complete to near complete resistance to yellow rust and other cereal rust diseases, was followed by a rapid erosion of resistance.

    Partial

  12. Development of RAPD based markers for wheat rust resistance ...

    African Journals Online (AJOL)

    Rust diseases are the major cause of low yield of wheat in Pakistan. Wheat breeders all over the world as well as in Pakistan are deriving rust resistance genes from alien species like Triticum ventricosum and introducing them in common wheat (Triticum aestivum). One such example is the introgression of rust resistance ...

  13. Molecular and genetic study of wheat rusts | Le Maitre | African ...

    African Journals Online (AJOL)

    Puccinia triticina, Puccinia graminis and Puccinia striiformis cause leaf, stem and yellow rust, respectively. Wheat rusts can cause losses as high as 70%. The rusts ability to evolve fungicide resistance has resulted in the use of resistant cultivars as the primary method of control. Breeding resistant cultivars is a long process ...

  14. Development of wheat germplasm for stem rust resistance in eastern ...

    African Journals Online (AJOL)

    Wheat (Triticum aestivum) rust outbreak is the primary production constraint in Eastern Africa. Ethiopia, Kenya and Uganda are hot spots for the epidemic of rusts, due to higher rates of evolution of new pathogen races, especially of the virulent stem rust (Puccinia graminis) race, Ug99. The objective of this study was to ...

  15. A High-Density Integrated DArTseq SNP-Based Genetic Map of Pisum fulvum and Identification of QTLs Controlling Rust Resistance

    Directory of Open Access Journals (Sweden)

    Eleonora Barilli

    2018-02-01

    Full Text Available Pisum fulvum, a wild relative of pea is an important source of allelic diversity to improve the genetic resistance of cultivated species against fungal diseases of economic importance like the pea rust caused by Uromyces pisi. To unravel the genetic control underlying resistance to this fungal disease, a recombinant inbred line (RIL population was generated from a cross between two P. fulvum accessions, IFPI3260 and IFPI3251, and genotyped using Diversity Arrays Technology. A total of 9,569 high-quality DArT-Seq and 8,514 SNPs markers were generated. Finally, a total of 12,058 markers were assembled into seven linkage groups, equivalent to the number of haploid chromosomes of P. fulvum and P. sativum. The newly constructed integrated genetic linkage map of P. fulvum covered an accumulated distance of 1,877.45 cM, an average density of 1.19 markers cM−1 and an average distance between adjacent markers of 1.85 cM. The composite interval mapping revealed three QTLs distributed over two linkage groups that were associated with the percentage of rust disease severity (DS%. QTLs UpDSII and UpDSIV were located in the LGs II and IV respectively and were consistently identified both in adult plants over 3 years at the field (Córdoba, Spain and in seedling plants under controlled conditions. Whenever they were detected, their contribution to the total phenotypic variance varied between 19.8 and 29.2. A third QTL (UpDSIV.2 was also located in the LGIVand was environmentally specific as was only detected for DS % in seedlings under controlled conditions. It accounted more than 14% of the phenotypic variation studied. Taking together the data obtained in the study, it could be concluded that the expression of resistance to fungal diseases in P. fulvum originates from the resistant parent IFPI3260.

  16. The Big Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research.

    Science.gov (United States)

    McCook, Stuart; Vandermeer, John

    2015-09-01

    Since 2008, there has been a cluster of outbreaks of the coffee rust (Hemileia vastatrix) across the coffee-growing regions of the Americas, which have been collectively described as the Big Rust. These outbreaks have caused significant hardship to coffee producers and laborers. This essay situates the Big Rust in a broader historical context. Over the past two centuries, coffee farmers have had to deal with the "curse of the Red Queen"-the need to constantly innovate in the face of an increasing range of threats, which includes the rust. Over the 20th century, particularly after World War II, national governments and international organizations developed a network of national, regional, and international coffee research institutions. These public institutions played a vital role in helping coffee farmers manage the rust. Coffee farmers have pursued four major strategies for managing the rust: bioprospecting for resistant coffee plants, breeding resistant coffee plants, chemical control, and agroecological control. Currently, the main challenge for researchers is to develop rust control strategies that are both ecologically and economically viable for coffee farmers, in the context of a volatile, deregulated coffee industry and the emergent challenges of climate change.

  17. The gene Sr33, an ortholog of barley Mla genes, encodes resistance to wheat stem rust race Ug99.

    Science.gov (United States)

    Periyannan, Sambasivam; Moore, John; Ayliffe, Michael; Bansal, Urmil; Wang, Xiaojing; Huang, Li; Deal, Karin; Luo, Mingcheng; Kong, Xiuying; Bariana, Harbans; Mago, Rohit; McIntosh, Robert; Dodds, Peter; Dvorak, Jan; Lagudah, Evans

    2013-08-16

    Wheat stem rust, caused by the fungus Puccinia graminis f. sp. tritici, afflicts bread wheat (Triticum aestivum). New virulent races collectively referred to as "Ug99" have emerged, which threaten global wheat production. The wheat gene Sr33, introgressed from the wild relative Aegilops tauschii into bread wheat, confers resistance to diverse stem rust races, including the Ug99 race group. We cloned Sr33, which encodes a coiled-coil, nucleotide-binding, leucine-rich repeat protein. Sr33 is orthologous to the barley (Hordeum vulgare) Mla mildew resistance genes that confer resistance to Blumeria graminis f. sp. hordei. The wheat Sr33 gene functions independently of RAR1, SGT1, and HSP90 chaperones. Haplotype analysis from diverse collections of Ae. tauschii placed the origin of Sr33 resistance near the southern coast of the Caspian Sea.

  18. Polyphenoloxidase activity in coffee leaves and its role in resistance against the coffee leaf miner and coffee leaf rust.

    Science.gov (United States)

    Melo, Geraldo Aclécio; Shimizu, Milton Massao; Mazzafera, Paulo

    2006-02-01

    In plants, PPO has been related to defense mechanism against pathogens and insects and this role was investigated in coffee trees regarding resistance against a leaf miner and coffee leaf rust disease. PPO activity was evaluated in different genotypes and in relation to methyl-jasmonate (Meja) treatment and mechanical damage. Evaluations were also performed using compatible and incompatible interactions of coffee with the fungus Hemileia vastatrix (causal agent of the leaf orange rust disease) and the insect Leucoptera coffeella (coffee leaf miner). The constitutive level of PPO activity observed for the 15 genotypes ranged from 3.8 to 88 units of activity/mg protein. However, no direct relationship was found with resistance of coffee to the fungus or insect. Chlorogenic acid (5-caffeoylquinic acid), the best substrate for coffee leaf PPO, was not related to resistance, suggesting that oxidation of other phenolics by PPO might play a role, as indicated by HPLC profiles. Mechanical damage, Meja treatment, H. vastatrix fungus inoculation and L. coffeella infestation caused different responses in PPO activity. These results suggest that coffee resistance may be related to the oxidative potential of the tissue regarding the phenolic composition rather than simply to a higher PPO activity.

  19. Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat.

    Science.gov (United States)

    Kaur, Jagdeep; Fellers, John; Adholeya, Alok; Velivelli, Siva L S; El-Mounadi, Kaoutar; Nersesian, Natalya; Clemente, Thomas; Shah, Dilip

    2017-02-01

    Rust fungi of the order Pucciniales are destructive pathogens of wheat worldwide. Leaf rust caused by the obligate, biotrophic basidiomycete fungus Puccinia triticina (Pt) is an economically important disease capable of causing up to 50 % yield losses. Historically, resistant wheat cultivars have been used to control leaf rust, but genetic resistance is ephemeral and breaks down with the emergence of new virulent Pt races. There is a need to develop alternative measures for control of leaf rust in wheat. Development of transgenic wheat expressing an antifungal defensin offers a promising approach to complement the endogenous resistance genes within the wheat germplasm for durable resistance to Pt. To that end, two different wheat genotypes, Bobwhite and Xin Chun 9 were transformed with a chimeric gene encoding an apoplast-targeted antifungal plant defensin MtDEF4.2 from Medicago truncatula. Transgenic lines from four independent events were further characterized. Homozygous transgenic wheat lines expressing MtDEF4.2 displayed resistance to Pt race MCPSS relative to the non-transgenic controls in growth chamber bioassays. Histopathological analysis suggested the presence of both pre- and posthaustorial resistance to leaf rust in these transgenic lines. MtDEF4.2 did not, however, affect the root colonization of a beneficial arbuscular mycorrhizal fungus Rhizophagus irregularis. This study demonstrates that the expression of apoplast-targeted plant defensin MtDEF4.2 can provide substantial resistance to an economically important leaf rust disease in transgenic wheat without negatively impacting its symbiotic relationship with the beneficial mycorrhizal fungus.

  20. Leaf Rust of Wheat: Pathogen Biology, Variation and Host Resistance

    Directory of Open Access Journals (Sweden)

    James Kolmer

    2013-01-01

    Full Text Available Rusts are important pathogens of angiosperms and gymnosperms including cereal crops and forest trees. With respect to cereals, rust fungi are among the most important pathogens. Cereal rusts are heteroecious and macrocyclic requiring two taxonomically unrelated hosts to complete a five spore stage life cycle. Cereal rust fungi are highly variable for virulence and molecular polymorphism. Leaf rust, caused by Puccinia triticina is the most common rust of wheat on a worldwide basis. Many different races of P. triticina that vary for virulence to leaf rust resistance genes in wheat differential lines are found annually in the US. Molecular markers have been used to characterize rust populations in the US and worldwide. Highly virulent races of P. triticina are selected by leaf rust resistance genes in the soft red winter wheat, hard red winter wheat and hard red spring wheat cultivars that are grown in different regions of the US. Cultivars that only have race-specific leaf rust resistance genes that are effective in seedling plants lose their effective resistance and become susceptible within a few years of release. Cultivars with combinations of race non-specific resistance genes have remained resistant over a period of years even though races of the leaf rust population have changed constantly.

  1. Influence of Environmental Conditions and Genetic Background of Arabica Coffee (C. arabica L) on Leaf Rust (Hemileia vastatrix) Pathogenesis

    Science.gov (United States)

    Toniutti, Lucile; Breitler, Jean-Christophe; Etienne, Hervé; Campa, Claudine; Doulbeau, Sylvie; Urban, Laurent; Lambot, Charles; Pinilla, Juan-Carlos H.; Bertrand, Benoît

    2017-01-01

    Global warming is a major threat to agriculture worldwide. Between 2008 and 2013, some coffee producing countries in South and Central America suffered from severe epidemics of coffee leaf rust (CLR), resulting in high economic losses with social implications for coffee growers. The climatic events not only favored the development of the pathogen but also affected the physiological status of the coffee plant. The main objectives of the study were to evaluate how the physiological status of the coffee plant modified by different environmental conditions impact on the pathogenesis of CLR and to identify indicators of the physiological status able to predict rust incidence. Three rust susceptible genotypes (one inbred line and two hybrids) were grown in controlled conditions with a combination of thermal regime (TR), nitrogen and light intensity close to the field situation before being inoculated with the rust fungus Hemileia vastatrix. It has been demonstrated that a TR of 27-22°C resulted in 2000 times higher sporulation than with a TR of 23–18°C. It has been also shown that high light intensity combined with low nitrogen fertilization modified the CLR pathogenesis resulting in huge sporulation. CLR sporulation was significantly lower in the F1 hybrids than in the inbred line. The hybrid vigor may have reduced disease incidence. Among the many parameters studied, parameters related to photosystem II and photosynthetic electron transport chain components appeared as indicators of the physiological status of the coffee plant able to predict rust sporulation intensity. Taken together, these results show that CLR sporulation not only depends on the TR but also on the physiological status of the coffee plant, which itself depends on agronomic conditions. Our work suggests that vigorous varieties combined with a shaded system and appropriate nitrogen fertilization should be part of an agro-ecological approach to disease control. PMID:29234340

  2. The poplar Rust-Induced Secreted Protein (RISP inhibits the growth of the leaf rust pathogen Melampsora larici-populina and triggers cell culture alkalinisation

    Directory of Open Access Journals (Sweden)

    Benjamin ePetre

    2016-02-01

    Full Text Available Plant cells secrete a wide range of proteins in extracellular spaces in response to pathogen attack. The poplar Rust-Induced Secreted Protein (RISP is a small cationic protein of unknown function that was identified as the most induced gene in poplar leaves during immune responses to the leaf rust pathogen Melampsora larici-populina, an obligate biotrophic parasite. Here, we combined in planta and in vitro molecular biology approaches to tackle the function of RISP. Using a RISP-mCherry fusion transiently expressed in Nicotiana benthamiana leaves, we demonstrated that RISP is secreted into the apoplast. A recombinant RISP specifically binds to M. larici-populina urediniospores and inhibits their germination. It also arrests the growth of the fungus in vitro and on poplar leaves. Interestingly, RISP also triggers poplar cell culture alkalinisation and is cleaved at the C-terminus by a plant-encoded mechanism. Altogether our results indicate that RISP is an antifungal protein that has the ability to trigger cellular responses.

  3. Identification of Green Rust in Groundwater

    DEFF Research Database (Denmark)

    Christiansen, Bo C.; Balic Zunic, Tonci; Dideriksen, Knud

    2009-01-01

    Green rust, a family of Fe(II),Fe(III) layered double hydroxides, is believed to be present in environments close to the Fe(II)/Fe(III) transition zone. Attempts to identify members of this family in nature have proven difficult because the material is oxidized after only a few minutes exposure t...

  4. Endoplasmic reticulum subcompartments in a plant parasitic fungus and in baker's yeast: differential distribution of lumenal proteins.

    Science.gov (United States)

    Bachem, U; Mendgen, K

    1995-06-01

    His-Asp-Glu-Leu (HDEL)-bearing proteins were quantified in different endoplasmic reticulum (ER) subcompartments of Saccharomyces cerevisiae and the plant parasite Uromyces viciae-fabae by immuno-electron microscopy (immuno-EM). In both fungi, the immunogold labeling of these proteins within the ER was three times greater than within the nuclear envelope. In U. viciae-fabae, the ER in germinating uredospores differed from the ER in fungal structures produced within the plant, e.g., haustoria. In haustoria, the cisternal ER differentiated large tubular-vesicular complexes (TVC). TVC contained higher levels of HDEL-bearing proteins than ordinary ER cisternae. ELISA readings also indicated an increased concentration of these proteins in isolated haustoria compared to germinating uredospores. In S. cerevisiae, the ER was differentiated into cortical and internal regions. Immuno-EM revealed that labeling of the binding protein (BiP) was lower in the ER of the cell cortex. Heat shock increased BiP signals, but the relative distribution within the ER did not change. Our results suggest that ER subcompartments can be differentiated by immunogold labeling of proteins with a retention signal. In special cases, such as in the parasitic phase of rust fungi, these proteins accumulate to higher levels in ER subcompartments, probably as a response to plant-induced stress.

  5. Melampsora rust on Salix in short rotation cultivation. Plant protection against fungi and bacteria in deciduous plantations. Final report for the period 1997-1999; Melampsora-rost paa Salix i energiskogsodling. Vaextskydd i intensivodlad loevskog mot svampar och bakterier. Slutrapport foer perioden 1997-1999

    Energy Technology Data Exchange (ETDEWEB)

    Ramstedt, Mauritz [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Plant Pathology and Biological Control Unit

    2000-04-01

    The project has focussed on the diseases of Salix in short rotation forestry, with emphasis on the rust fungus, Melampsora ssp., which could be responsible for significant loss in production and dieback of plants. We have studied the virulence patterns of the rust population (rust pathotypes) to be able to give qualified support for analysis of field trials for resistance and advice for choice of breeding strategies. The rust population includes a large number of pathotypes and the variousness indicate a high capacity to adapt to new clones or plantation strategies. The sexual cycle is of crucial importance and gives the rust the property of recombination and exchange of virulence factors every season. The idea with clonal mixtures instead of monoclonal plantations is evaluated on Northern Ireland. The records of pathotypes and genotypes in the rust population in these trials, would after a repeated assessment and analysis give valuable indications concerning the development and selection of rust in relation to plantation design. The question is if a clonal mixture affects the infection pressure or if surrounding plantations and long distance spore migration will eliminate this effect. An analysis of the rust population on european willows in Chile is also performed to study the role of local adaptation and selection as compared to long distance migration of spores. The rust is pathotyped and analysed by AFLP to reveal the relatedness with european rust and analyze the level of long distance exchange. Possible exchange of virulence factors between the continents is of utmost importance for the outcome of the resistance breeding and longevity of the new more resistant clones.

  6. QTLs for resistance to the false brome rust Puccinia brachypodii in the model grass Brachypodium distachyon L.

    Science.gov (United States)

    Barbieri, Mirko; Marcel, Thierry C; Niks, Rients E; Francia, Enrico; Pasquariello, Marianna; Mazzamurro, Valentina; Garvin, David F; Pecchioni, Nicola

    2012-02-01

    The potential of the model grass Brachypodium distachyon L. (Brachypodium) for studying grass-pathogen interactions is still underexploited. We aimed to identify genomic regions in Brachypodium associated with quantitative resistance to the false brome rust fungus Puccinia brachypodii . The inbred lines Bd3-1 and Bd1-1, differing in their level of resistance to P. brachypodii, were crossed to develop an F(2) population. This was evaluated for reaction to a virulent isolate of P. brachypodii at both the seedling and advanced growth stages. To validate the results obtained on the F(2), resistance was quantified in F(2)-derived F(3) families in two experiments. Disease evaluations showed quantitative and transgressive segregation for resistance. A new AFLP-based Brachypodium linkage map consisting of 203 loci and spanning 812 cM was developed and anchored to the genome sequence with SSR and SNP markers. Three false brome rust resistance QTLs were identified on chromosomes 2, 3, and 4, and they were detected across experiments. This study is the first quantitative trait analysis in Brachypodium. Resistance to P. brachypodii was governed by a few QTLs: two acting at the seedling stage and one acting at both seedling and advanced growth stages. The results obtained offer perspectives to elucidate the molecular basis of quantitative resistance to rust fungi.

  7. Expression of a synthetic rust fungal virus cDNA in yeast.

    Science.gov (United States)

    Cooper, Bret; Campbell, Kimberly B; Garrett, Wesley M

    2016-01-01

    Mycoviruses are viruses that infect fungi. Recently, mycovirus-like RNAs were sequenced from the fungus Phakopsora pachyrhizi, the causal agent of soybean rust. One of the RNAs appeared to represent a novel mycovirus and was designated Phakopsora pachyrhizi virus 2383 (PpV2383). The genome of PpV2383 resembles Saccharomyces cerevisiae virus L-A, a double-stranded (ds) RNA mycovirus of yeast. PpV2383 encodes two major, overlapping open reading frames with similarity to gag (capsid protein) and pol (RNA-dependent RNA polymerase), and a -1 ribosomal frameshift is necessary for the translation of a gag-pol fusion protein. Phylogenetic analysis of pol relates PpV2383 to members of the family Totiviridae, including L-A. Because the obligate biotrophic nature of P. pachyrhizi makes it genetically intractable for in vivo analysis and because PpV2383 is similar to L-A, we synthesized a DNA clone of PpV2383 and tested its infectivity in yeast cells. PpV2383 RNA was successfully expressed in yeast, and mass spectrometry confirmed the translation of gag and gag-pol fusion proteins. There was, however, no production of PpV2383 dsRNA, the evidence of viral replication. Neither the presence of endogenous L-A nor the substitution of the 5' and 3' untranslated regions with those from L-A was sufficient to rescue replication of PpV2383. Nevertheless, the proof of transcription and translation from the clone in vivo are steps toward confirming that PpV2383 is a mycovirus. Further development of a surrogate biological system for the study of rust mycoviruses is necessary, and such research may facilitate biological control of rust diseases.

  8. Annotation of a hybrid partial genome of the coffee rust (Hemileia vastatrix) contributes to the gene repertoire catalog of the Pucciniales.

    Science.gov (United States)

    Cristancho, Marco A; Botero-Rozo, David Octavio; Giraldo, William; Tabima, Javier; Riaño-Pachón, Diego Mauricio; Escobar, Carolina; Rozo, Yomara; Rivera, Luis F; Durán, Andrés; Restrepo, Silvia; Eilam, Tamar; Anikster, Yehoshua; Gaitán, Alvaro L

    2014-01-01

    Coffee leaf rust caused by the fungus Hemileia vastatrix is the most damaging disease to coffee worldwide. The pathogen has recently appeared in multiple outbreaks in coffee producing countries resulting in significant yield losses and increases in costs related to its control. New races/isolates are constantly emerging as evidenced by the presence of the fungus in plants that were previously resistant. Genomic studies are opening new avenues for the study of the evolution of pathogens, the detailed description of plant-pathogen interactions and the development of molecular techniques for the identification of individual isolates. For this purpose we sequenced 8 different H. vastatrix isolates using NGS technologies and gathered partial genome assemblies due to the large repetitive content in the coffee rust hybrid genome; 74.4% of the assembled contigs harbor repetitive sequences. A hybrid assembly of 333 Mb was built based on the 8 isolates; this assembly was used for subsequent analyses. Analysis of the conserved gene space showed that the hybrid H. vastatrix genome, though highly fragmented, had a satisfactory level of completion with 91.94% of core protein-coding orthologous genes present. RNA-Seq from urediniospores was used to guide the de novo annotation of the H. vastatrix gene complement. In total, 14,445 genes organized in 3921 families were uncovered; a considerable proportion of the predicted proteins (73.8%) were homologous to other Pucciniales species genomes. Several gene families related to the fungal lifestyle were identified, particularly 483 predicted secreted proteins that represent candidate effector genes and will provide interesting hints to decipher virulence in the coffee rust fungus. The genome sequence of Hva will serve as a template to understand the molecular mechanisms used by this fungus to attack the coffee plant, to study the diversity of this species and for the development of molecular markers to distinguish races/isolates.

  9. Annotation of a hybrid partial genome of the Coffee Rust (Hemileia vastatrix contributes to the gene repertoire catalogue of the Pucciniales

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Cristancho

    2014-10-01

    Full Text Available Coffee leaf rust caused by the fungus Hemileia vastatrix is the most damaging disease to coffee worldwide. The pathogen has recently appeared in multiple outbreaks in coffee producing countries resulting in significant yield losses and increases in costs related to its control. New races/isolates are constantly emerging as evidenced by the presence of the fungus in plants that were previously resistant. Genomic studies are opening new avenues for the study of the evolution of pathogens, the detailed description of plant-pathogen interactions and the development of molecular techniques for the identification of individual isolates. For this purpose we sequenced 8 different H. vastatrix isolates using NGS technologies and gathered partial genome assemblies due to the large repetitive content in the coffee rust hybrid genome; 74.4% of the assembled contigs harbor repetitive sequences. A hybrid assembly of 333Mb was built based on the 8 isolates; this assembly was used for subsequent analyses.Analysis of the conserved gene space showed that the hybrid H. vastatrix genome, though highly fragmented, had a satisfactory level of completion with 91.94% of core protein-coding orthologous genes present. RNA-Seq from urediniospores was used to guide the de novo annotation of the H. vastatrix gene complement. In total, 14,445 genes organized in 3,921 families were uncovered; a considerable proportion of the predicted proteins (73.8% were homologous to other Pucciniales species genomes. Several gene families related to the fungal lifestyle were identified, particularly 483 predicted secreted proteins that represent candidate effector genes and will provide interesting hints to decipher virulence in the coffee rust fungus. The genome sequence of Hva will serve as a template to understand the molecular mechanisms used by this fungus to attack the coffee plant, to study the diversity of this species and for the development of molecular markers to distinguish

  10. Genomic Prediction of Genetic Values for Resistance to Wheat Rusts

    Directory of Open Access Journals (Sweden)

    Leonardo Ornella

    2012-11-01

    Full Text Available Durable resistance to the rust diseases of wheat ( L. can be achieved by developing lines that have race-nonspecific adult plant resistance conferred by multiple minor slow-rusting genes. Genomic selection (GS is a promising tool for accumulating favorable alleles of slow-rusting genes. In this study, five CIMMYT wheat populations evaluated for resistance were used to predict resistance to stem rust ( and yellow rust ( using Bayesian least absolute shrinkage and selection operator (LASSO (BL, ridge regression (RR, and support vector regression with linear or radial basis function kernel models. All parents and populations were genotyped using 1400 Diversity Arrays Technology markers and different prediction problems were assessed. Results show that prediction ability for yellow rust was lower than for stem rust, probably due to differences in the conditions of infection of both diseases. For within population and environment, the correlation between predicted and observed values (Pearson’s correlation [ρ] was greater than 0.50 in 90% of the evaluations whereas for yellow rust, ρ ranged from 0.0637 to 0.6253. The BL and RR models have similar prediction ability, with a slight superiority of the BL confirming reports about the additive nature of rust resistance. When making predictions between environments and/or between populations, including information from another environment or environments or another population or populations improved prediction.

  11. Orange rust in sugarcane: molecular identification in Rio de Janeiro State

    Directory of Open Access Journals (Sweden)

    Carla Vanessa Borges Castro

    2013-09-01

    Full Text Available Sugarcane (Saccharum spp. cultivation is one of the major agricultural activities in the Brazilian states. This study aimed to molecularly identify the pathogen associated with rust in sugarcane cultivars in the state of Rio de Janeiro and to suggest a control strategy. Among the 14 PCR-tested cultivars, Puccinia kuehnii infection was identified for RB947520, RB92606, RB835486, RB72454, SP89-11I5, SP83-2847, both from infected leaf sample and from urediniospores. Puccinia kuehnii was not detected by PCR for the cultivars RB955971, RB951541, RB92579, RB867515, RB855536, SP91-1049, SP80-3280, SP80-1816. This is the first molecular detection of this fungus in the state of Rio de Janeiro for six of the 14 analyzed cultivars.

  12. A pigeonpea gene confers resistance to Asian soybean rust in soybean.

    Science.gov (United States)

    Kawashima, Cintia G; Guimarães, Gustavo Augusto; Nogueira, Sônia Regina; MacLean, Dan; Cook, Doug R; Steuernagel, Burkhard; Baek, Jongmin; Bouyioukos, Costas; Melo, Bernardo do V A; Tristão, Gustavo; de Oliveira, Jamile Camargos; Rauscher, Gilda; Mittal, Shipra; Panichelli, Lisa; Bacot, Karen; Johnson, Ebony; Iyer, Geeta; Tabor, Girma; Wulff, Brande B H; Ward, Eric; Rairdan, Gregory J; Broglie, Karen E; Wu, Gusui; van Esse, H Peter; Jones, Jonathan D G; Brommonschenkel, Sérgio H

    2016-06-01

    Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is one of the most economically important crop diseases, but is only treatable with fungicides, which are becoming less effective owing to the emergence of fungicide resistance. There are no commercial soybean cultivars with durable resistance to P. pachyrhizi, and although soybean resistance loci have been mapped, no resistance genes have been cloned. We report the cloning of a P. pachyrhizi resistance gene CcRpp1 (Cajanus cajan Resistance against Phakopsora pachyrhizi 1) from pigeonpea (Cajanus cajan) and show that CcRpp1 confers full resistance to P. pachyrhizi in soybean. Our findings show that legume species related to soybean such as pigeonpea, cowpea, common bean and others could provide a valuable and diverse pool of resistance traits for crop improvement.

  13. Characterization and selection of location for resistance to sugarcane brown rust disease under cuban conditions

    Directory of Open Access Journals (Sweden)

    Joaquín Montalván Delgado

    2016-01-01

    Full Text Available The sugarcane brown rust disease is caused by fungus Puccinia melanocephala Sydow & P. Sydow and it is one of the more importance diseases. The environment where the sugarcane is cultivated is constituted by numerous factors and its combination contributes to the formation of different development and production conditions, what influences in the varietal disease resistance. With the objective of to characterize and to define the resistance tests location to the brown rust disease were carried out experiments in 6 location of the country. Eleven varieties and six patterns were studied. The climatic variables were analyzed during the period in each location and they were carried out evaluations in different ages of the plant and number of the leaves. The quantity of pustules, long of the most frequent pustules, size of the biggest pustules and area per - centage occupied by pustules were evaluated. The data were analyzed statistically. Differential behavior of the locations and the importance of the relative humidity and the temperatures in the manifestation of the disease symptoms were proven. All the locations were important although similarity exists between Matanzas and Villa Clara and between Camagüey and Holguín. Mayabeque and Santiago de Cuba didn’t present similarity with any other one. These 6 locations can be used for the resistance tests and to define the progenitors’ Santiago de Cuba, Holguín, Villa Clara and Mayabeque

  14. Insights into Tan Spot and Stem Rust Resistance and Susceptibility by Studying the Pre-Green Revolution Global Collection of Wheat.

    Science.gov (United States)

    Abdullah, Sidrat; Sehgal, Sunish Kumar; Jin, Yue; Turnipseed, Brent; Ali, Shaukat

    2017-04-01

    Tan spot (TS), caused by the fungus Pyrenophora tritici-repentis (Died) Drechs, is an important foliar disease of wheat and has become a threat to world wheat production since the 1970s. In this study a globally diverse pre-1940s collection of 247 wheat genotypes was evaluated against Ptr ToxA, P. tritici-repentis race 1, and stem rust to determine if; (i) acquisition of Ptr ToxA by the P. tritici-repentis from Stagonospora nodorum led to increased pathogen virulence or (ii) incorporation of TS susceptibility during development stem rust resistant cultivars led to an increase in TS epidemics globally. Most genotypes were susceptible to stem rust; however, a range of reactions to TS and Ptr ToxA were observed. Four combinations of disease-toxin reactions were observed among the genotypes; TS susceptible-Ptr ToxA sensitive, TS susceptible-Ptr ToxA insensitive, TS resistant-Ptr ToxA insensitive, and TS resistant-Ptr ToxA toxin sensitive. A weak correlation (r = 0.14 for bread wheat and -0.082 for durum) was observed between stem rust susceptibility and TS resistance. Even though there were no reported epidemics in the pre-1940s, TS sensitive genotypes were widely grown in that period, suggesting that Ptr ToxA may not be an important factor responsible for enhanced prevalence of TS.

  15. Plant-Fungus Marriages

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Plant-Fungus Marriages. Ramesh Maheshwari. General Article Volume 11 Issue 4 April 2006 pp 33-44. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/011/04/0033-0044. Keywords. Fungi ...

  16. Antibiotic Resistance and Fungus

    Centers for Disease Control (CDC) Podcasts

    2017-02-28

    Dr. David Denning, President of the Global Action Fund for Fungal Infections and an infectious diseases clinician, discusses antimicrobial resistance and fungus.  Created: 2/28/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/28/2017.

  17. Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses.

    Science.gov (United States)

    Ramachandran, Sowmya R; Yin, Chuntao; Kud, Joanna; Tanaka, Kiwamu; Mahoney, Aaron K; Xiao, Fangming; Hulbert, Scot H

    2017-01-01

    Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (acids), secreted proteins, with no predicted functions were selected for the HR suppression assay using Nicotiana benthamiana, in which each of the proteins were transiently expressed and evaluated for their ability to suppress HR caused by four cytotoxic effector-R gene combinations (Cp/Rx, ATR13/RPP13, Rpt2/RPS-2, and GPA/RBP-1) and one mutated R gene-Pto(Y207D). Nine out of twenty proteins, designated Shr1 to Shr9 (suppressors of hypersensitive response), were found to suppress HR in N. benthamiana. These effectors varied in the effector-R gene defenses they suppressed, indicating these pathogens can interfere with a variety of host defense pathways. In addition to HR suppression, effector Shr7 also suppressed PAMP-triggered immune response triggered by flg22. Finally, delivery of Shr7 through Pseudomonas fluorescens EtHAn suppressed nonspecific HR induced by Pseudomonas syringae DC3000 in wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.

  18. Coprecipitation of Arsenate and Arsenite with Green Rust Minerals

    Science.gov (United States)

    The objectives of this experiment were to evaluate the extent and nature of arsenic co-precipitation with green rusts and to examine the influence of arsenic incorporation on the mineralogy of formed solid phases. Stoichiometric green rusts were obtained by coprecipitation of fe...

  19. An economic evaluation of fusiform rust protection research

    Science.gov (United States)

    F.W. Cubbage; John M. Pye; T.P. Holmes; J.E. Wagner

    2000-01-01

    Fusiform rust is a widespread and damaging disease of loblolly pine (P. taeda) and slash pine (P. elliottii) in the South. Research has identified families of these pines with improved genetic resistance to the disease, allowing production and planting of resistant seedlings in areas at risk. This study compared the cost of fusiform rust research to the simulated...

  20. Genetic studies in wheat for leaf rust resistance ( Puccinia recondita ...

    African Journals Online (AJOL)

    Genetic studies in wheat for leaf rust resistance (Puccinia recondita). F Hussain, M Ashraf, MA Hameed, N Hussain, RA Sial. Abstract. Leaf rust is a major disease of wheat crop in the world as a whole. This study was undertaken to find the genetic effects of adult plant leaf resistance in wheat (Triticum aestivum L.).

  1. Wheat rusts in the United States in 2016

    Science.gov (United States)

    In 2016, wheat stripe rust caused by Puccinia striiformis f. sp. graminis was widespread throughout the United States. Cool temperatures and abundant rainfall in the southern Great Plains allowed stripe rust to become widely established and spread throughout the Great Plains and eastern United State...

  2. Interacting genes in the pine-fusiform rust forest pathosystem

    Science.gov (United States)

    H.V. Amerson; T.L. Kubisiak; S.A. Garcia; G.C. Kuhlman; C.D. Nelson; S.E. McKeand; T.J. Mullin; B. Li

    2005-01-01

    Fusiform rust (FR) disease of pines, caused by Cronartium quercuum f.sp. fusiforme (Cqf), is the most destructive disease in pine plantations of the southern U. S. The NCSU fusiform rust program, in conjunction with the USDA-Forest Service in Saucier, MS and Athens, GA, has research underway to elucidate some of the genetic interactions in this...

  3. Stem rust seedling resistance genes in Ethiopian wheat cultivars ...

    African Journals Online (AJOL)

    Stem rust caused by Puccinia graminis f. sp. tritici is one of the major biotic limiting factors for wheat production in Ethiopia. Host plant resistance is the best option to manage stem rust from its economic and environmental points of view. Wheat cultivars are released for production without carrying race specific tests against ...

  4. Marker-assisted pyramiding of Thinopyrumderived leaf rust ...

    Indian Academy of Sciences (India)

    2017-03-20

    Mar 20, 2017 ... Key words: Wheat, leaf rust, molecular marker, gene pyramiding,marker assisted selection. Abstract. The study was undertaken to pyramid two effective leaf rust resistance genes (Lr19 and Lr24) derived from Thinopyrum(syn.Agropyron), in the susceptible but agronomically superior wheat cultivar HD2733 ...

  5. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat–Ae. caudata introgression line (IL) T291-2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major ...

  6. Pathological and molecular characterizations of slow leaf rusting in ...

    African Journals Online (AJOL)

    Sundeep

    2012-10-18

    Oct 18, 2012 ... Leaf rust caused by Puccinia triticina, is a globally important fungal disease of wheat (Triticum aestivum L. em. Thell), resulting in significant yield losses, sometimes up to 40% worldwide. In this study we investigated slow rusting resistance at pathological and molecular level. Fifteen (15) wheat genotypes ...

  7. Transfer of stripe rust resistance from Aegilops variabilis to bread ...

    African Journals Online (AJOL)

    In terms of area, the bread wheat producing regions of China comprise the largest area in the world that is constantly threatened by stripe rust epidemics. Consequently, it is important to exploit new adultplant resistance genes in breeding. This study reports the transfer of stripe rust resistance from Aegilops variabilis to ...

  8. stem rust seedling resistance genes in ethiopian wheat cultivars

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    Stem rust caused by Puccinia graminis f. sp. tritici is one of the major biotic limiting factors for wheat production in Ethiopia. Host plant resistance is the best option to manage stem rust from its economic and environmental points of view. Wheat cultivars are released for production without carrying race specific tests against ...

  9. leaf and stripe rust resistance among ethiopian grown wheat ...

    African Journals Online (AJOL)

    ADMIN

    ABSTRACT: Ethiopian grown wheat varieties and lines were studied to identify germplasm sources possessing resistance to leaf rust caused by Puccinia triticina and stripe rust (P. striiformis). Sixty-four lines were included of which 38 were bread wheat (Triticum aestivum, 2n=6x=42, AABBDD) and 26 durum wheat (T.

  10. Progress on introduction of rust resistance genes into confection sunflower

    Science.gov (United States)

    Sunflower rust (Puccinia helianthi) emerged as a serious disease in the last few years. Confection sunflower is particularly vulnerable to the disease due to the lack of resistance sources. The objectives of this project are to transfer rust resistance genes from oil sunflower to confectionery sunfl...

  11. Computer simulation of white pine blister rust epidemics

    Science.gov (United States)

    Geral I. McDonald; Raymond J. Hoff; William R. Wykoff

    1981-01-01

    A simulation of white pine blister rust is described in both word and mathematical models. The objective of this first generation simulation was to organize and analyze the available epidemiological knowledge to produce a foundation for integrated management of this destructive rust of 5-needle pines. Verification procedures and additional research needs are also...

  12. Genetic analysis of resistance to soybean rust disease | Kiryowa ...

    African Journals Online (AJOL)

    Soybean rust (Phakopsora pachyrhizi Sydow.) causes the most damage of all the pathogens known to attack soybean (Glycine max. Merril). A study was conducted in Uganda to estimate the magnitude of genetic parameters controlling soybean rust resistance and to estimate narrow sense heritability of the resistance.

  13. Characterization of stem rust resistance gene Sr2 in Indian wheat ...

    African Journals Online (AJOL)

    Stem rust or black rust is one of the most important diseases of wheat worldwide. In India, central, peninsular and southern hill zones are particularly prone to stem rust where favourable environmental conditions exist. The recent emergence of wheat stem rust race Ug99 (TTKSK) and related strains threatens global wheat ...

  14. Characterization of stem rust resistance gene Sr2 in Indian wheat ...

    African Journals Online (AJOL)

    SONY

    2013-05-01

    May 1, 2013 ... Stem rust or black rust is one of the most important diseases of wheat worldwide. In India, central, peninsular and southern hill zones are particularly prone to stem rust where favourable environmental conditions exist. The recent emergence of wheat stem rust race Ug99 (TTKSK) and related strains.

  15. A greenhouse-based inoculation protocol for fungi causing crown rust and stem rust diseases of Kentucky bluegrass turf

    Science.gov (United States)

    Rusts are destructive fungal diseases that can cause severe thinning and unattractive discoloration of kentucky bluegrass (KBG; Poa pratensis L.). Currently, turfgrass breeding programs rely on field evaluations to screen KBG germplasm for rust resistance; methods that are expensive, labor intensive...

  16. A green method of diaphragm spring's anti-rusting with high quality and efficiency

    Science.gov (United States)

    Huang, Xinming; Hua, Wenlin

    2017-10-01

    This paper introduces a green method of diaphragm spring's anti-rusting, which is of high quality, high efficiency and low consumption. It transforms the phosphating way of anti-rusting to physical anti-rusting that directly coat anti-rusting oil on the surface of the spring, and transforms the manual-oiling or oil-immersion to fully-automatically ultrasonic oiling. Hence, this method will completely change the way of diaphgragm spring's anti-rusting.

  17. Rust fungi on Annonaceae: the genus Sphaerophragmium.

    Science.gov (United States)

    Beenken, Ludwig; Berndt, Reinhard

    2010-01-01

    Seven species of the rust genus Sphaerophragmium occur on members of the tropical plant family Annonaceae. Uropyxis gerstneri is recombined to S. gerstneri. A new species, S. xylopiae, is described from Xylopia acutiflora. The host plant of S. boanense is identified as Mitrella sp. Sphaerophragmium pulchrum is transferred to Dicheirinia. The anatomy of telia with teliospores and parasitizing mycelium is described and illustrated in detail. A new type of M-haustorium, which emanates laterally from intracellular hypha, is detected in S. monodorae. An identification key is given.

  18. Effects of simulated acidic rain on host-parasite interaction in plant diseases. [Cronartium fusiforme, Quercus phellos, Meloidogyne hapla, Phaseolus vulgaris, Uromyces phaseoli, Pseudomonas phaseolicola

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1978-02-01

    The effects of simulated rain acidified with sulfuric acid were studied on five host-parasite systems. Plants were exposed in greenhouse or field to simulated rain of pH 3.2 or pH 6.0 in amounts and intervals common to weather patterns of North Carolina. Simulated acidic rain resulted in: (i) an 86% inhibition of the number of telia produced by Cronartium fusiforme on willow oak (Quercus phellos); (ii) a 66% inhibition in the reproduction of root-knot nematode (Meloidogyne hapla) on field-grown kidney beans (Phaseolus vulgaris Red Kidney); (iii) a 29% decrease in the percentage of leaf area of field-grown kidney beans affected by Uromyces phaseoli; and (iv) either stimulated or inhibited development of halo blight on kidney bean (caused by Pseudomonas phaseolicola), depending upon the stage of the disease cycle in which the treatments were applied. The effect varied as follows: (i) simulated acidic rain applied to plants before inoculation increased disease severity by 42%; (ii) suspension of bacteria in acidic rain resulted in no infection; and (iii) acidic rain applied to plants after infection inhibited disease development by 22%. Results suggest that the acidity of rain is an environmental parameter which should be of concern to plant pathologists and agricultural and forest ecologists. 22 references, 2 tables.

  19. Incorporation of Monovalent Cations in Sulfate Green Rust

    DEFF Research Database (Denmark)

    Christiansen, B. C.; Dideriksen, K.; Katz, A.

    2014-01-01

    Green rust is a naturally occurring layered mixed-valent ferrous-ferric hydroxide, which can react with a range of redox-active compounds. Sulfate-bearing green rust is generally thought to have interlayers composed of sulfate and water. Here, we provide evidence that the interlayers also contain...... with water showed that Na+ and K+ were structurally fixed in the interlayer, whereas Rb+ and Cs+ could be removed, resulting in a decrease in the basal layer spacing. The incorporation of cations in the interlayer opens up new possibilities for the use of sulfate green rust for exchange reactions with both...

  20. Direct mechanical dispersion and in vitro culture of fusiform rust fungus single basidiospores

    Science.gov (United States)

    Alex M. Diner

    1999-01-01

    Single basidiospores of Cronartium quercuum f. sp. fusiforme were cast from telia suspended over a solidified nutritional medium affixed to an operating orbital shaker. Spores thus mechanically dispersed and isolated, germinated to develop single-genotype colonies.

  1. Utilização de glifosato para o controle de ferrugem da soja Glyphosate application on soybean rust control

    Directory of Open Access Journals (Sweden)

    Rafael Moreira Soares

    2008-04-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de glifosato sobre a germinação de esporos de Phakopsora pachyrhizi e no controle da ferrugem da soja, aplicado preventiva e erradicativamente, em condições controladas. A germinação de esporos foi avaliada tendo-se vertido, em meio de cultura, soluções de esporos com diferentes concentrações do glifosato (0, 100, 1.000, 10.000 e 20.000 ppm e fungicidas. Para avaliar o controle da ferrugem, plantas foram pulverizadas com glifosato, com variação da dose e do momento, tendo-se medido a severidade da doença. Houve efeito do produto sobre os esporos do fungo, o que reduziu sua germinação. As pulverizações em plantas, em casa de vegetação, mostraram um efeito do produto sobre a ferrugem, quando aplicado preventivamente, porém com período de proteção curto e fungitoxicidade inferior à do fungicida tebuconazole. O uso do glifosato, avaliado nesse ensaio, não deve ser visto como medida de manejo de ferrugem, e não interfere nas práticas habituais de controle da ferrugem da soja.The objective of this work was to evaluate the effect of glyphosate on the germination of Phakopsora pachyrhizi spores, and on soybean rust control; applications were either preventive or eradicative under controlled conditions. The germination of spores was evaluated by pouring spores solutions on culture medium, with different concentrations of glyphosate (0, 100, 1,000, 10,000 and 20,000 ppm and fungicides. For the rust control evaluation, plants were sprayed with glyphosate, varying doses and moments, and estimating the disease severity. The product reduced spores germination. Plants sprayed in greenhouse conditions, showed effect of the product on rust, when applied preventively, but with short protection period and lower fungus toxicity than tebuconazole fungicide. The use of glyphosate, evaluated in this trial, must not be taken as a rust management measure, and should not interfere in usual

  2. Landscape context and scale differentially impact coffee leaf rust, coffee berry borer, and coffee root-knot nematodes.

    Science.gov (United States)

    Avelino, Jacques; Romero-Gurdián, Alí; Cruz-Cuellar, Héctor F; Declerck, Fabrice A J

    2012-03-01

    Crop pest and disease incidences at plot scale vary as a result of landscape effects. Two main effects can be distinguished. First, landscape context provides habitats of variable quality for pests, pathogens, and beneficial and vector organisms. Second, the movements of these organisms are dependent on the connectivity status of the landscape. Most of the studies focus on indirect effects of landscape context on pest abundance through their predators and parasitoids, and only a few on direct effects on pests and pathogens. Here we studied three coffee pests and pathogens, with limited or no pressure from host-specific natural enemies, and with widely varying life histories, to test their relationships with landscape context: a fungus, Hemileia vastatrix, causal agent of coffee leaf rust; an insect, the coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae); and root-knot nematodes, Meloidogyne spp. Their incidence was assessed in 29 coffee plots from Turrialba, Costa Rica. In addition, we characterized the landscape context around these coffee plots in 12 nested circular sectors ranging from 50 to 1500 m in radius. We then performed correlation analysis between proportions of different land uses at different scales and coffee pest and disease incidences. We obtained significant positive correlations, peaking at the 150 m radius, between coffee berry borer abundance and proportion of coffee in the landscape. We also found significant positive correlations between coffee leaf rust incidence and proportion of pasture, peaking at the 200 m radius. Even after accounting for plot level predictors of coffee leaf rust and coffee berry borer through covariance analysis, the significance of landscape structure was maintained. We hypothesized that connected coffee plots favored coffee berry borer movements and improved its survival. We also hypothesized that wind turbulence, produced by low-wind-resistance land uses such as pasture, favored removal of coffee

  3. Changing the game: using integrative genomics to probe virulence mechanisms of the stem rust pathogen Puccinia graminis f. sp. tritici

    Directory of Open Access Journals (Sweden)

    Melania eFigueroa

    2016-02-01

    , including the related flax rust fungus. Up regulation of gene expression in haustoria and evidence for diversifying selection are two useful parameters to identify candidate Avr genes. Recently, we have also applied machine learning approaches to agnostically predict candidate effectors. Here, we review progress in stem rust pathogenomics and approaches currently underway to identify Avr genes recognized by wheat

  4. RESEARCH ON THE RUST FUNGI DURING THE TWENTIETH CENTURY.

    Science.gov (United States)

    Staples, Richard C.

    2000-01-01

    Interest in the rust fungi derives from their success as plant pathogens. For example, the epidemic on coffee had serious economic and social impacts on diverse cultures. During the century, research on the rust germling shifted from a study of germling development, including a search for the signals that induce differentiation, to an examination of the genes expressed during host colonization. Research on host resistance was most influenced by Stakman, who studied the genetics and epidemiology of rust disease. His innovations enabled Flor to propose the gene-for-gene hypothesis, a concept that stimulated development of resistant crops, and led to research that gradually shifted during the century to an examination of the molecular basis of rust genetics.

  5. Mapping of quantitative adult plant field resistance to leaf rust and stripe rust in two European winter wheat populations reveals co-location of three QTL conferring resistance to both rust pathogens.

    Science.gov (United States)

    Buerstmayr, Maria; Matiasch, Lydia; Mascher, Fabio; Vida, Gyula; Ittu, Marianna; Robert, Olivier; Holdgate, Sarah; Flath, Kerstin; Neumayer, Anton; Buerstmayr, Hermann

    2014-09-01

    We detected several, most likely novel QTL for adult plant resistance to rusts. Notably three QTL improved resistance to leaf rust and stripe rust simultaneously indicating broad spectrum resistance QTL. The rusts of wheat (Puccinia spp.) are destructive fungal wheat diseases. The deployment of resistant cultivars plays a central role in integrated rust disease management. Durability of resistance would be preferred, but is difficult to analyse. The Austrian winter wheat cultivar Capo was released in the 1989 and grown on a large acreage during more than two decades and maintained a good level of quantitative leaf rust and stripe rust resistance. Two bi-parental mapping populations: Capo × Arina and Capo × Furore were tested in multiple environments for severity of leaf rust and stripe rust at the adult plant stage in replicated field experiments. Quantitative trait loci associated with leaf rust and stripe rust severity were mapped using DArT and SSR markers. Five QTL were detected in multiple environments associated with resistance to leaf rust designated as QLr.ifa-2AL, QLr.ifa-2BL, QLr.ifa-2BS, QLr.ifa-3BS, and QLr.ifa-5BL, and five for resistance to stripe rust QYr.ifa-2AL, QYr.ifa-2BL, QYr.ifa-3AS, QYr.ifa-3BS, and QYr.ifa-5A. For all QTL apart from two (QYr.ifa-3AS, QLr.ifa-5BL) Capo contributed the resistance improving allele. The leaf rust and stripe rust resistance QTL on 2AL, 2BL and 3BS mapped to the same chromosome positions, indicating either closely linked genes or pleiotropic gene action. These three multiple disease resistance QTL (QLr.ifa-2AL/QYr.ifa-2AL, QLr.ifa.2BL/QYr.ifa-2BL, QLr.ifa-3BS/QYr.ifa.3BS) potentially contribute novel resistance sources for stripe rust and leaf rust. The long-lasting resistance of Capo apparently rests upon a combination of several genes. The described germplasm, QTL and markers are applicable for simultaneous resistance improvement against leaf rust and stripe rust.

  6. Modeling landscape-scale pathogen spillover between domesticated and wild hosts: Asian soybean rust and kudzu.

    Science.gov (United States)

    Fabiszewski, Anna M; Umbanhowar, James; Mitchell, Charles E

    2010-03-01

    Many emerging pathogens infect both domesticated and wild host species, creating the potential for pathogen transmission between domesticated and wild populations. This common situation raises the question of whether managing negative impacts of disease on a focal host population (whether domesticated, endangered, or pest) requires management of only the domesticated host, only the wild host, or both. To evaluate the roles of domesticated and wild hosts in the dynamics of shared pathogens, we developed a spatially implicit model of a pathogen transmitted by airborne spores between two host species restricted to two different landscape patch types. As well as exploring the general dynamics and implications of the model, we fully parameterized our model for Asian soybean rust, a multihost infectious disease that emerged in the United States in 2004. The rust fungus Phakopsora pachyrhizi infects many legume species, including soybeans (Glycine max) and the nonnative invasive species kudzu (Pueraria montana var. lobata). Our model predicts that epidemics are driven by the host species that is more abundant in the landscape. In managed landscapes, this will generally be the domesticated host. However, many pathogens overwinter on a wild host, which acts as the source of initial inoculum at the start of the growing season. Our model predicts that very low local densities of infected wild hosts, surviving in landscape patches separate from the domesticated host, are sufficient to initiate epidemics in the domesticated host, such that managing epidemics by reducing wild host local density may not be feasible. In contrast, managing to reduce pathogen infection of a domesticated host can reduce disease impacts on wild host populations.

  7. Moessbauer Characterization of Rust Obtained in an Accelerated Corrosion Test

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K. E.; Morales, A. L.; Arroyave, C. E.; Barrero, C. A. [Universidad de Antioquia, Grupo de Corrosion y Proteccion, Departamento de Ingenieria de Materiales (Colombia); Cook, D. C. [Old Dominion University, Department of Physics (United States)

    2003-06-15

    We have performed drying-humectation cyclical processes (CEBELCOR) on eight A36 low carbon steel coupons in NaCl solutions containing 1x10{sup -2} M and 1x10{sup -1} M concentrations. The main purpose of these experiments is to contribute to the understanding of the conditions for akaganeite formation. Additionally, and with the idea to perform a complete characterization of the rust, this work also considers the formation of other iron oxide phases. The corrosion products were characterized by Moessbauer spectroscopy and X-ray diffraction techniques. Gravimetric analysis demonstrates that the coupons presented high corrosion rates. Magnetite/maghemite was common in the rust stuck to the steel surface, whereas akaganeite was present only in traces. In the rust collected from the solutions, i.e., the rust that goes away from the metal surface easily, a magnetite/maghemite was not present and akaganeite showed up in larger quantities. These results support the idea that high concentrations of Cl{sup -} ions are required for the akaganeite formation. We concluded that akaganeite is not easily bonded to the rust layer; this may lead to the formation of a less protective rust layer and to higher corrosion rates.

  8. Efeito de alta temperatura no desenvolvimento de Hemileia vastatrix em cafeeiro suscetível Effect of temperature on coffee rust evolution

    Directory of Open Access Journals (Sweden)

    Ivan José Antunes Ribeiro

    1978-01-01

    Full Text Available Foi estudado o efeito de temperaturas elevadas no desenvolvimento da ferrugem do cafeeiro, verificando-se que a exposição de plantas a temperatura próxima de 40ºC por quatro horas durante quatro dias foi suficiente para impedir a evolução da moléstia. Períodos menores foram ineficientes para afetar o desenvolvimento do fungo.The development of rust epidemics in tropical conditions of Brazil has been different than previously expected. Despite of high humidity the development is reduced to a minimum during the summer. High temperature was assumed to have a detrimental effect on the rust development. This paper reports the results of a study concerning the effect of high temperature on Hemileia vastatrix development. Temperature treatment of inoculated young plants at 40(0C for 4 hours in 4 consecutive days was sufficient to prevent rust development. The curative effect was permanent indicating that the fungus was destroyed inside the plant tissue. Practical implications of such results are considered.

  9. Relationship between the specific surface area of rust and the electrochemical behavior of rusted steel in a wet-dry acid corrosion environment

    Science.gov (United States)

    Liu, Wei; Zhao, Qing-he; Li, Shuan-zhu

    2017-01-01

    The relationship between the specific surface area (SSA) of rust and the electrochemical behavior of rusted steel under wet-dry acid corrosion conditions was investigated. The results showed that the corrosion current density first increased and then decreased with increasing SSA of the rust during the corrosion process. The structure of the rust changed from single-layer to double-layer, and the γ-FeOOH content decreased in the inner layer of the rust with increasing corrosion time; by contrast, the γ-FeOOH content in the outer layer was constant. When the SSA of the rust was lower than the critical SSA corresponding to the relative humidity during the drying period, condensed water in the micropores of the rust could evaporate, which prompted the diffusion of O2 into the rust and the following formation process of γ-FeOOH, leading to an increase of corrosion current density with increasing corrosion time. However, when the SSA of the rust reached or exceeded the critical SSA, condensate water in the micro-pores of the inner layer of the rust could not evaporate which inhibited the diffusion of O2 and decreased the γ-FeOOH content in the inner rust, leading to a decrease of corrosion current density with increasing corrosion time.

  10. Characterization of a tryptophan 2-monooxygenase gene from Puccinia graminis f. sp. tritici involved in auxin biosynthesis and rust pathogenicity.

    Science.gov (United States)

    Yin, Chuntao; Park, Jeong-Jin; Gang, David R; Hulbert, Scot H

    2014-03-01

    The plant hormone indole-3-acetic acid (IAA) is best known as a regulator of plant growth and development but its production can also affect plant-microbe interactions. Microorganisms, including numerous plant-associated bacteria and several fungi, are also capable of producing IAA. The stem rust fungus Puccinia graminis f. sp. tritici induced wheat plants to accumulate auxin in infected leaf tissue. A gene (Pgt-IaaM) encoding a putative tryptophan 2-monooxygenase, which makes the auxin precursor indole-3-acetamide (IAM), was identified in the P. graminis f. sp. tritici genome and found to be expressed in haustoria cells in infected plant tissue. Transient silencing of the gene in infected wheat plants indicated that it was required for full pathogenicity. Expression of Pgt-IaaM in Arabidopsis caused a typical auxin expression phenotype and promoted susceptibility to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000.

  11. Wheat TaRab7 GTPase is part of the signaling pathway in responses to stripe rust and abiotic stimuli.

    Science.gov (United States)

    Liu, Furong; Guo, Jun; Bai, Pengfei; Duan, Yinhui; Wang, Xiaodong; Cheng, Yulin; Feng, Hao; Huang, Lili; Kang, Zhensheng

    2012-01-01

    Small GTP-binding proteins function as regulators of specific intercellular fundamental biological processes. In this study, a small GTP-binding protein Rab7 gene, designated as TaRab7, was identified and characterized from a cDNA library of wheat leaves infected with Puccinia striiformis f. sp. tritici (Pst) the wheat stripe rust pathogen. The gene was predicted to encode a protein of 206 amino acids, with a molecular mass of 23.13 KDa and an isoeletric point (pI) of 5.13. Further analysis revealed the presence of a conserved signature that is characteristic of Rab7, and phylogenetic analysis demonstrated that TaRab7 has the highest similarity to a small GTP binding protein gene (BdRab7-like) from Brachypodium distachyon. Quantitative real-time PCR assays revealed that the expression of TaRab7 was higher in the early stage of the incompatible interactions between wheat and Pst than in the compatible interaction, and the transcription level of TaRab7 was also highly induced by environmental stress stimuli. Furthermore, knocking down TaRab7 expression by virus induced gene silencing enhanced the susceptibility of wheat cv. Suwon 11 to an avirulent race CYR23. These results imply that TaRab7 plays an important role in the early stage of wheat-stripe rust fungus interaction and in stress tolerance.

  12. Wheat TaRab7 GTPase is part of the signaling pathway in responses to stripe rust and abiotic stimuli.

    Directory of Open Access Journals (Sweden)

    Furong Liu

    Full Text Available Small GTP-binding proteins function as regulators of specific intercellular fundamental biological processes. In this study, a small GTP-binding protein Rab7 gene, designated as TaRab7, was identified and characterized from a cDNA library of wheat leaves infected with Puccinia striiformis f. sp. tritici (Pst the wheat stripe rust pathogen. The gene was predicted to encode a protein of 206 amino acids, with a molecular mass of 23.13 KDa and an isoeletric point (pI of 5.13. Further analysis revealed the presence of a conserved signature that is characteristic of Rab7, and phylogenetic analysis demonstrated that TaRab7 has the highest similarity to a small GTP binding protein gene (BdRab7-like from Brachypodium distachyon. Quantitative real-time PCR assays revealed that the expression of TaRab7 was higher in the early stage of the incompatible interactions between wheat and Pst than in the compatible interaction, and the transcription level of TaRab7 was also highly induced by environmental stress stimuli. Furthermore, knocking down TaRab7 expression by virus induced gene silencing enhanced the susceptibility of wheat cv. Suwon 11 to an avirulent race CYR23. These results imply that TaRab7 plays an important role in the early stage of wheat-stripe rust fungus interaction and in stress tolerance.

  13. Identification of QTL conferring resistance to stripe rust (Puccinia striiformis f. sp. hordei) and leaf rust (Puccinia hordei) in barley using nested association mapping (NAM).

    Science.gov (United States)

    Vatter, Thomas; Maurer, Andreas; Perovic, Dragan; Kopahnke, Doris; Pillen, Klaus; Ordon, Frank

    2018-01-01

    The biotrophic rust fungi Puccinia hordei and Puccinia striiformis are important barley pathogens with the potential to cause high yield losses through an epidemic spread. The identification of QTL conferring resistance to these pathogens is the basis for targeted breeding approaches aiming to improve stripe rust and leaf rust resistance of modern cultivars. Exploiting the allelic richness of wild barley accessions proved to be a valuable tool to broaden the genetic base of resistance of barley cultivars. In this study, SNP-based nested association mapping (NAM) was performed to map stripe rust and leaf rust resistance QTL in the barley NAM population HEB-25, comprising 1,420 lines derived from BC1S3 generation. By scoring the percentage of infected leaf area, followed by calculation of the area under the disease progress curve and the average ordinate during a two-year field trial, a large variability of resistance across and within HEB-25 families was observed. NAM based on 5,715 informative SNPs resulted in the identification of twelve and eleven robust QTL for resistance against stripe rust and leaf rust, respectively. Out of these, eight QTL for stripe rust and two QTL for leaf rust are considered novel showing no overlap with previously reported resistance QTL. Overall, resistance to both pathogens in HEB-25 is most likely due to the accumulation of numerous small effect loci. In addition, the NAM results indicate that the 25 wild donor QTL alleles present in HEB-25 strongly differ in regard to their individual effect on rust resistance. In future, the NAM concept will allow to select and combine individual wild barley alleles from different HEB parents to increase rust resistance in barley. The HEB-25 results will support to unravel the genetic basis of rust resistance in barley, and to improve resistance against stripe rust and leaf rust of modern barley cultivars.

  14. Genetic analysis and location of gene for resistance to stripe rust in ...

    Indian Academy of Sciences (India)

    2013-08-06

    yellow) rust. It is very important to clarify its genetic character of resistance to stripe rust and to develop the molecular markers linked to resistance genes. The NIL Taichung. 29*6/Strubes Dickkopf, which was obtained by ...

  15. Wheat Rust Information Resources - Integrated tools and data for improved decision making

    DEFF Research Database (Denmark)

    Hodson, David; Hansen, Jens Grønbech; Lassen, Poul

    Wheat rusts present an ever-changing global threat to the worlds wheat crop. Emergence of virulent new races in one region has implications for other regions, due to wind-borne or human-borne movements. Therefore informed decision making regarding control and mitigation of wheat rusts requires...... an integrated set of datasets on both pathogen and host at the global scale. The Global Cereal Rust Monitoring System (GCRMS), created under the Durable Rust resistance in Wheat (DRRW) project, represents a unique and increasingly comprehensive resource of rust information. A suite of tools are now available...... giving access to an unprecedented set of data for rust surveys, alternate hosts (barberry), rust pathotypes, trap nurseries and resistant cultivars. Standardized protocols for data collection have permitted the development of a comprehensive data management system, named the Wheat Rust Toolbox...

  16. QTL mapping of adult-plant resistance to stripe rust in wheat line P9897

    Science.gov (United States)

    Stripe rust (or yellow rust), caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating fungal disease of common wheat. Wheat line P9897 showed adult-plant resistance (APR) to stripe rust for several years. To map resistance quantitative trait loci (QTL), F2:3 lines from a cross of P9897...

  17. Using hierarchical clustering of secreted protein families to classify and rank candidate effectors of rust fungi

    Science.gov (United States)

    Rust fungi are obligate biotrophic pathogens causing considerable damage on crop plants. P. graminis f. sp. tritici, the causal agent of wheat stem rust, and M. larici-populina, the poplar rust pathogen, have strong deleterious impact on wheat and poplar wood production, respectively. The recently r...

  18. Introgression of a leaf rust resistance gene from Aegilops caudata to ...

    Indian Academy of Sciences (India)

    Keywords. alien introgression; molecular mapping; leaf rust; Puccinia triticina; Triticum aestivum; Aegilops caudata. Abstract. Rusts are the most important biotic constraints limiting wheat productivity worldwide. Deployment of cultivars with broad spectrum rust resistance is the only environmentally viable option to combat ...

  19. Identification of leaf rust resistant gene Lr10 in Pakistani wheat ...

    African Journals Online (AJOL)

    Leaf (brown) rust is the major disease of wheat in Pakistan and other countries. The disease is more effectively controlled when several rust resistance genes are pyramided into a single line. Molecular survey was conducted to screen 25 Pakistan wheat germplasm for the presence of leaf rust resistance gene Lr10 using ...

  20. Duplications and losses in gene families of rust pathogens highlight putative effectors

    Science.gov (United States)

    Amanda L. Pendleton; Katherine E. Smith; Nicolas Feau; Francis M. Martin; Igor V. Grigoriev; Richard Hamelin; C.Dana Nelson; J.Gordon Burleigh; John M. Davis

    2014-01-01

    Rust fungi are a group of fungal pathogens that cause some of the world’s most destructive diseases of trees and crops . A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen...

  1. Soybean rust resistance sources and inheritance in the common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Souza, T L P O; Dessaune, S N; Moreira, M A; Barros, E G

    2014-07-25

    Soybean rust (SBR), caused by the fungus Phakopsora pachyrhizi, has been reported in common bean (Phaseolus vulgaris L.) cultivars and elite lines that were infected under controlled and natural field conditions in South Africa, the United States, Argentina, and Brazil. Although SBR is currently not a top priority problem for the common bean crop, many bean breeders are concerned about this disease because of the high severity and virulence diversity of P. pachyrhizi and its broad host range. In this study, a set of 44 P. vulgaris genotypes were tested for resistance to P. pachyrhizi; these genotypes included resistance sources to several fungal common bean diseases, carioca-, black- and red-seeded Brazilian cultivars, and elite lines that were developed by the main common bean breeding programs in Brazil. Twenty-four SBR resistance sources were identified. They presented the reddish-brown (RB) lesion type, characterizing resistance reactions. In addition to the RB lesion type, the PI181996 line presented the lowest disease severity mean score, considering its associated standard error value. For this reason, it was crossed with susceptible lines to study the inheritance of resistance. The results support the hypothesis that resistance to SBR in PI181996 is monogenic and dominant. We propose that this SBR resistance gene, the first to be identified and characterized in common bean, might be designated as Pkp-1.

  2. Weather and Climate Indicators for Coffee Rust Disease

    Science.gov (United States)

    Georgiou, S.; Imbach, P. A.; Avelino, J.; Anzueto, F.; del Carmen Calderón, G.

    2014-12-01

    Coffee rust is a disease that has significant impacts on the livelihoods of those who are dependent on the Central American coffee sector. Our investigation has focussed on the weather and climate indicators that favoured the high incidence of coffee rust disease in Central America in 2012 by assessing daily temperature and precipitation data available from 81 weather stations in the INSIVUMEH and ANACAFE networks located in Guatemala. The temperature data were interpolated to determine the corresponding daily data at 1250 farms located across Guatemala, between 400 and 1800 m elevation. Additionally, CHIRPS five day (pentad) data has been used to assess the anomalies between the 2012 and the climatological average precipitation data at farm locations. The weather conditions in 2012 displayed considerable variations from the climatological data. In general the minimum daily temperatures were higher than the corresponding climatology while the maximum temperatures were lower. As a result, the daily diurnal temperature range was generally lower than the corresponding climatological range, leading to an increased number of days where the temperatures fell within the optimal range for either influencing the susceptibility of the coffee plants to coffee rust development during the dry season, or for the development of lesions on the coffee leaves during the wet season. The coffee rust latency period was probably shortened as a result, and farms at high altitudes were impacted due to these increases in minimum temperature. Factors taken into consideration in developing indicators for coffee rust development include: the diurnal temperature range, altitude, the environmental lapse rate and the phenology. We will present the results of our study and discuss the potential for each of the derived weather and climatological indicators to be used within risk assessments and to eventually be considered for use within an early warning system for coffee rust disease.

  3. 78 FR 27855 - Black Stem Rust; Additions of Rust-Resistant Species and Varieties

    Science.gov (United States)

    2013-05-13

    ... yield of infected wheat, oat, barley, and rye crops. In addition to infecting small grains, the fungus... varieties. The nursery and floriculture industries that may be affected by this rule are largely composed of... of plant pests can result in damage to crops and losses to the U.S. agricultural sector. For the...

  4. Postulation of rust resistance genes in Nordic spring wheat genotypes and identification of widely effective sources of resistance against the Australian rust flora.

    Science.gov (United States)

    Randhawa, Mandeep; Bansal, Urmil; Lillemo, Morten; Miah, Hanif; Bariana, Harbans

    2016-11-01

    Wild relatives, landraces and cultivars from different geographical regions have been demonstrated as the sources of genetic variation for resistance to rust diseases. This study involved assessment of diversity for resistance to three rust diseases among a set of Nordic spring wheat cultivars. These cultivars were tested at the seedling stage against several pathotypes of three rust pathogens in the greenhouse. All stage stem rust resistance genes Sr7b, Sr8a, Sr12, Sr15, Sr17, Sr23 and Sr30, and leaf rust resistance genes Lr1, Lr3a, Lr13, Lr14a, Lr16 and Lr20 were postulated either singly or in different combinations among these cultivars. A high proportion of cultivars were identified to carry linked rust resistance genes Sr15 and Lr20. Although 51 cultivars showed variation against Puccinia striiformis f. sp. tritici (Pst) pathotypes used in this study, results were not clearly contrasting to enable postulation of stripe rust resistance genes in these genotypes. Stripe rust resistance gene Yr27 was postulated in four cultivars and Yr1 was present in cultivar Zebra. Cultivar Tjalve produced low stripe rust response against all Pst pathotypes indicating the presence either of a widely effective resistance gene or combination of genes with compensating pathogenic specificities. Several cultivars carried moderate to high level of APR to leaf rust and stripe rust. Seedling stem rust susceptible cultivar Aston exhibited moderately resistant to moderately susceptible response, whereas other cultivars belonging to this class were rated moderately susceptible or higher. Molecular markers linked with APR genes Yr48, Lr34/Yr18/Sr57, Lr68 and Sr2 detected the presence of these genes in some genotypes.

  5. short communication sources of stem rust resistance in ethiopian ...

    African Journals Online (AJOL)

    Administrator

    SHORT COMMUNICATION. SOURCES OF STEM RUST RESISTANCE IN ETHIOPIAN TETRAPLOID. WHEAT ACCESSIONS ... 1Department of Plant Sciences, Alemaya University, P. O. Box 138, Dire Dawa, Ethiopia. 2Southern Agricultural Research Institute, P. O. Box 06, Awassa, Ethiopia. (Received 20 May, 2005; ...

  6. White pines, Ribes, and blister rust: a review and synthesis

    Science.gov (United States)

    Brian W. Geils; Kim E. Hummer; Richard S. Hunt

    2010-01-01

    For over a century, white pine blister rust (Cronartium ribicola) has linked white pines (Strobus) with currants and gooseberries (Ribes) in a complex and serious disease epidemic in Asia, Europe, and North America. Because of ongoing changes in climate, societal demands for forests and their amenities, and scientific advances in genetics and proteomics, our current...

  7. Resistance of three interspecific white pine hybrids to blister rust

    Science.gov (United States)

    R. Z. Callaham

    1962-01-01

    Three white pine hybrids exposed to infection by white pine blister rust (Cronartium ribicola Fischer) since 1946 have inherited the relative resistance of their parental species. The hybrids were produced from controlled pollinations in 1940 and 1941 at the Institute of Forest Genetics, Placerville, Calif. Twelve seedlings of each hybrid were...

  8. Genetic studies in wheat for leaf rust resistance (Puccinia recondita)

    African Journals Online (AJOL)

    user

    2011-04-18

    Apr 18, 2011 ... 3Plant Breeding institute, University of Sydney, Camden, NSW, Australia. .... leaf rust at the beginning of the culms elongation stage of plant growth. Fresh inoculum was collected from spreader rows, while plots were inoculated by spraying and dusting. ... modified Cobb scale method (Peterson et al., 1948).

  9. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Anonymous 2013 The package of practices for crops of Punjab, rabi. 2013–14. Punjab Agricultural University, Ludhiana, India. Bansal M., Kaur S., Dhaliwal H., Chhuneja P., Bariana H. and. Bansal U. 2016 Introgression of linked rust resistance genes Lr76 and Yr70 from Aegilops umbellulata to wheat chromosome 5DS.

  10. Identification of pathogen avirulencegenes in the fusiform rust pathosystem

    Science.gov (United States)

    John M. Davis; Katherine E. Smith; Amanda Pendleton; Jason A. Smith; C. Dana Nelson

    2012-01-01

    The Cronartium quercuum f.sp. fusiforme (Cqf) whole genome sequencing project will enable identification of avirulence genes in the most devastating pine fungal pathogen in the southeastern United States. Amerson and colleagues (unpublished) have mapped nine fusiform rust resistance genes in loblolly pine,...

  11. Reductive and sorptive properties of sulfate green rust (GRSO4)

    DEFF Research Database (Denmark)

    Nedel, Sorin

    The Fe(II), Fe(III) hydroxide containing sulfate in its structure, called sulfate green rust (GRSO4), can effectively reduce and convert contaminants to less mobile and less toxic forms. However, the ability of GRSO4 to remove positively charged species from solution, via sorption, is very limited...

  12. Blister rust control in the management of western white pine

    Science.gov (United States)

    Kenneth P. Davis; Virgil D. Moss

    1940-01-01

    The forest industry of the western white pine region depends on the production of white pine as a major species on about 2,670,000 acres of commercial forest land. Continued production of this species and maintenance of the forest industry at anything approaching its present level is impossible unless the white pine blister rust is controlled. Existing merchantable...

  13. White pines, Ribes, and blister rust: integration and action

    Science.gov (United States)

    R. S. Hunt; B. W. Geils; K. E. Hummer

    2010-01-01

    The preceding articles in this series review the history, biology and management of white pine blister rust in North America, Europe and eastern Asia. In this integration, we connect and discuss seven recurring themes important for understanding and managing epidemics of Cronartium ribicola in the white pines (five-needle pines in subgenus Strobus). Information and...

  14. Induced resistance and gene expression in wheat against leaf rust ...

    African Journals Online (AJOL)

    uvp

    2013-05-15

    May 15, 2013 ... Key words: Wheat leaf rust, induced resistance, priming, gene expression, immunoblotting, crude Agapanthus africanus extract. ... agents, including several synthetic and natural plant activators (Garcia-Brugger et al., ... priming and direct defence activation (van Hulten et al.,. 2006). The identification of new ...

  15. Coffee Leaf Rust Epidemics ( Hemileia vastatrix ) in Montane Coffee ...

    African Journals Online (AJOL)

    Thirty coffee trees were selected from each forest (three sites within a forest) coffee population to record incidence (percent rusted leaves), severity (percent leaf area damaged) and sporulated lesion density (number of lesion per leaf, SLD) from selected six branches per tree. An average of 10-12 leaves per branch was ...

  16. Genetics and mapping of the R₁₁ gene conferring resistance to recently emerged rust races, tightly linked to male fertility restoration, in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Seiler, G J; Vick, B A; Gulya, T J

    2012-09-01

    Sunflower oil is one of the major sources of edible oil. As the second largest hybrid crop in the world, hybrid sunflowers are developed by using the PET1 cytoplasmic male sterility system that contributes to a 20 % yield advantage over the open-pollinated varieties. However, sunflower production in North America has recently been threatened by the evolution of new virulent pathotypes of sunflower rust caused by the fungus Puccinia helianthi Schwein. Rf ANN-1742, an 'HA 89' backcross restorer line derived from wild annual sunflower (Helianthus annuus L.), was identified as resistant to the newly emerged rust races. The aim of this study was to elucidate the inheritance of rust resistance and male fertility restoration and identify the chromosome location of the underlying genes in Rf ANN-1742. Chi-squared analysis of the segregation of rust response and male fertility in F(2) and F(3) populations revealed that both traits are controlled by single dominant genes, and that the rust resistance gene is closely linked to the restorer gene in the coupling phase. The two genes were designated as R ( 11 ) and Rf5, respectively. A set of 723 mapped SSR markers of sunflower was used to screen the polymorphism between HA 89 and the resistant plant. Bulked segregant analysis subsequently located R ( 11 ) on linkage group (LG) 13 of sunflower. Based on the SSR analyses of 192 F(2) individuals, R ( 11 ) and Rf5 both mapped to the lower end of LG13 at a genetic distance of 1.6 cM, and shared a common marker, ORS728, which was mapped 1.3 cM proximal to Rf5 and 0.3 cM distal to R ( 11 ) (Rf5/ORS728/R ( 11 )). Two additional SSRs were linked to Rf5 and R ( 11 ): ORS995 was 4.5 cM distal to Rf5 and ORS45 was 1.0 cM proximal to R ( 11 ). The advantage of such an introduced alien segment harboring two genes is its large phenotypic effect and simple inheritance, thereby facilitating their rapid deployment in sunflower breeding programs. Suppressed recombination was observed in LGs 2, 9

  17. Relocation of a rust resistance gene R 2 and its marker-assisted gene pyramiding in confection sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Ma, G J; Long, Y M; Hulke, B S; Gong, L; Markell, S G

    2015-03-01

    The rust resistance gene R 2 was reassigned to linkage group 14 of the sunflower genome. DNA markers linked to R 2 were identified and used for marker-assisted gene pyramiding in a confection type genetic background. Due to the frequent evolution of new pathogen races, sunflower rust is a recurring threat to sunflower production worldwide. The inbred line Morden Cross 29 (MC29) carries the rust resistance gene, R 2 , conferring resistance to numerous races of rust fungus in the US, Canada, and Australia, and can be used as a broad-spectrum resistance resource. Based on phenotypic assessments and SSR marker analyses on the 117 F2 individuals derived from a cross of HA 89 with MC29 (USDA), R 2 was mapped to linkage group (LG) 14 of the sunflower, and not to the previously reported location on LG9. The closest SSR marker HT567 was located at 4.3 cM distal to R 2 . Furthermore, 36 selected SNP markers from LG14 were used to saturate the R 2 region. Two SNP markers, NSA_002316 and SFW01272, flanked R 2 at a genetic distance of 2.8 and 1.8 cM, respectively. Of the three closely linked markers, SFW00211 amplified an allele specific for the presence of R 2 in a marker validation set of 46 breeding lines, and SFW01272 was also shown to be diagnostic for R 2 . These newly developed markers, together with the previously identified markers linked to the gene R 13a , were used to screen 524 F2 individuals from a cross of a confection R 2 line and HA-R6 carrying R 13a . Eleven homozygous double-resistant F2 plants with the gene combination of R 2 and R 13a were obtained. This double-resistant line will be extremely useful in confection sunflower, where few rust R genes are available, risking evolution of new virulence phenotypes and further disease epidemics.

  18. Metodologias de preparação de amostras de ferrugem para estudos morfológicos de urediniósporos por meio de microscopia eletrônica de varredura Methodologies processed of some rusts fungi by scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Louise Larissa May-De Mio

    2006-09-01

    Full Text Available Amostras de urediniósporos de ferrugens das espécies Melampsora epitea Thum., Melampsora medusae Thuem., Hemileia vastatrix Berk., Uromyces appendiculatum Pers., Puccinia sorghi Schwein., Tranzschelia discolor Fuckel e Phakopsora euvitis Ono, coletadas dos hospedeiros, chorão (Salix sp., álamo (Populus deltoides Bartr. Ex. Marsh, cafeeiro (Coffea arabica L., feijoeiro (Phaseolus vulgaris L., milho (Zea mays L., pessegueiro (Prunus persicae L. e videira (Vitis vinifera L. respectivamente, foram processadas de 3 formas: a método convencional (fixação em glutaraldeído e tetróxido de ósmio, desidratação em acetona e secagem ao ponto crítico; b método do vapor de ósmio e metalização com ouro; c metalização direta de amostras (utilizado para esporos soltos. A técnica de fratura de amostra congelada em nitrogênio líquido também foi testada para o estudo do interior de pústulas da ferrugem da videira (P. euvitis. As amostras foram visualizadas em microscópio eletrônico de varredura no NAP/MEPA da ESALQ/USP. Procedeu-se à mensuração dos esporos e as imagens obtidas foram capturadas pelo software LeoUserInterface e processadas utilizando-se o programa de computador "Corel Draw". Em todos os métodos analisados obteve-se uma boa preservação da estrutura possibilitando imagens de alta qualidade. No entanto, para esporos livres (mantidos em cápsula de gelatina o método da metalização direta foi mais prático e rápido. Para observação das pústulas em tecido vegetal os dois métodos de processamento de amostras avaliados proporcionaram resultados satisfatórios. A técnica de fratura em nitrogênio líquido também permitiu perfeita visualização do interior das pústulas da ferrugem da videira.Samples from Urediniospores of some rust fungi such as Melampsora epitea, Melampsora medusae, Hemileia vastatrix, Uromyces appendiculatum, Puccinia sorghi, Tranzschelia discolor and Phakopsora euvitis respectively from Salix sp

  19. Characterization of a wheat HSP70 gene and its expression in response to stripe rust infection and abiotic stresses.

    Science.gov (United States)

    Duan, Ying-Hui; Guo, Jun; Ding, Ke; Wang, Shu-Juan; Zhang, Hong; Dai, Xi-Wei; Chen, Yue-Ying; Govers, Francine; Huang, Li-Li; Kang, Zhen-Sheng

    2011-01-01

    Members of the family of 70-kD heat shock proteins (HSP70 s) play various stress-protective roles in plants. In this study, a wheat HSP70 gene was isolated from a suppression subtractive hybridization (SSH) cDNA library of wheat leaves infected by Puccinia striiformis f. sp. tritici. The gene, that was designated as TaHSC70, was predicted to encode a protein of 690 amino acids, with a molecular mass of 73.54 KDa and a pI of 5.01. Further analysis revealed the presence of a conserved signature that is characteristic for HSP70s and phylogenetic analysis demonstrated that TaHSC70 is a homolog of chloroplast HSP70s. TaHSC70 mRNA was present in leaves of both green and etiolated wheat seedlings and in stems and roots. The transcript level in roots was approximately threefold less than in leaves but light-dark treatment did not charge TaHSC70 expression. Following heat shock of wheat seedlings at 40°C, TaHSC70 expression increased in leaves of etiolated seedlings but remained stable at the same level in green seedlings. In addition, TaHSC70 was differentially expressed during an incompatible and compatible interaction with wheat-stripe rust, and there was a transient increase in expression upon treatment with methyl jasmonate (MeJA) treatment. Salicylic acid (SA), ethylene (ET) and abscisic acid (ABA) treatments had no influence on TaHSC70 expression. These results suggest that TaHSC70 plays a role in stress-related responses, and in defense responses elicited by infection with stripe rust fungus and does so via a JA-dependent signal transduction pathway.

  20. In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections

    OpenAIRE

    Ellison, Mitchell A.; McMahon, Michael B.; Bonde, Morris R.; Palmer, Cristi L.; Luster, Douglas G

    2016-01-01

    Background Rust fungi are obligate pathogens with multiple life stages often including different spore types and multiple plant hosts. While individual rust pathogens are often associated with specific plants, a wide range of plant species are infected with rust fungi. To study the interactions between these important pathogenic fungi and their host plants, one must be able to differentiate fungal tissue from plant tissue. This can be accomplished using the In situ hybridization (ISH) protoco...

  1. Biological Control of Aquatic Plants with Pathogenic Fungi

    Science.gov (United States)

    1981-01-01

    United States only on Pontederia cordata L. and P. lanceolata Nutt. in New Ycrk, Florida, Pennsylvania, Virginia, North Carolina, Georgia, Missouri...Waterhyacinth Rust, and Uromyces pontederiae ," Mycologia., Vol 67, pp 653-657. Charudattan, R., and McKinney, D. E. 1978. "A Dutch Isolate of Fusarium...the teliospore in the rust on Eichhornia azurea (Swartz) Kunth. and the confirmation of this rust as Uromyces pontederiae Gerard. The fact that

  2. Inhibitive Performance of a Rust Converter on Corrosion of Mild Steel

    Science.gov (United States)

    Zhao, X. D.; Cheng, Y. F.; Fan, W.; Vladimir, C.; Volha, V.; Alla, T.

    2014-11-01

    In this work, a rust converter consisting of two steps of processing solutions was prepared to convert iron rust of the steel surface into a protective conversion film. The performance of the converter was evaluated in both neutral and acidic solutions by various electrochemical measurements, including potentiodynamic polarization curves and electrochemical impedance spectroscopy, and surface characterization. The effect of temperature was investigated. It was found that the rust converter is able to effectively convert the iron rust into a conversion film, serving as a barrier layer to block corrosive species from reaching the steel surface.

  3. Effect of stripe rust on the yield response of wheat to nitrogen

    Directory of Open Access Journals (Sweden)

    Rakhesh Devadas

    2014-08-01

    Full Text Available Nitrogen (N is the most important fertiliser element determining the productivity of wheat. N nutrition is known to affect the level of stripe rust infection, with higher N associated with increased disease severity. Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a major yield-limiting disease of wheat in Australia. This paper describes experiments designed to investigate the agronomic response to the interaction of various levels of N application and stripe rust severity in wheat varieties differing in response. Experimental plots were established in crop seasons 2006 and 2007 on the Liverpool Plains of northern NSW, Australia. Yield, biomass, grain protein content (GPC and harvest index (HI data were recorded. Increased rates of N increased the severity of stripe rust during grain filling. N application also increased yield and GPC in all varieties in both years. Stripe rust reduced the yield of the rust-susceptible wheat varieties, and GPC and proportion of added N recovered in the grain were also reduced in one year but not the other. It was evident from our experiment that stripe rust caused yield loss accompanied by either no change or reduction in GPC, indicating that the total amount of N entering the grain was reduced by stripe rust. The effects of stripe rust on N yield are most likely associated with reduced uptake of N during grain filling.

  4. A baseline analysis of the distribution, host-range, and severity of the rust Puccinia Psidii in the Hawaiian islands, 2005-2010

    Science.gov (United States)

    Anderson, Robert C.

    2012-01-01

    Puccinia psidii was first described by Winter (1884) on guava (Psidium guajava L.) in Brazil. The rust is still a major pest of native guava in Brazil and is often referred to as “guava rust” internationally. It is unusual among rust fungi because of its broad and ever-expanding host-range within the Myrtaceae plant family (Simpson et al. 2006). The pathogen is regarded as a major threat to Eucalyptus plantations and other Myrtaceae worldwide (Coutinho et al. 1998, Grgurinovic et al. 2006, Glen et al. 2007). Infections of leaves and meristems are particularly severe on susceptible seedlings, cuttings, young trees, and coppice, causing plants to be stunted and multi-branched, inhibiting normal growth and development, and sometimes causing death to young seedlings (Booth et al. 2000, Rayachhetry et al. 2001). The fungus has expanded its host-range in Brazil, affecting both native and introduced Myrtaceae (Coutinho et al. 1998). Since its discovery in 1884, P. psidii has continually been discovered to have an expanding host-range within the Myrtaceae, affecting hosts throughout much of South and Central America and the Caribbean. Spreading out originally from Brazil in 1884, the fungus has been reported on hosts in the following countries (first record in parentheses): Paraguay (1884), Uruguay (1889), Ecuador (1891), Colombia (1913), Puerto Rico (1913), Cuba (1926), Dominican Republic (1933), Venezuela (1934), Jamaica (1936), Argentina (1946), Dominica (1948), Trinidad and Tobago (1951), Guatemala (1968), United States (Florida; 1977), Mexico (1981), El Salvador (1987), and Costa Rica (1998) (Simpson et al. 2006). It is possible that P. psidii was present in El Salvador and Costa Rica prior to 1980, but was not reported until 1987 and 1998, respectively. Until recently, Puccinia psidii was restricted to the Neotropics, Mexico, and the state of Florida in the United States. While the rust has been present in Florida for over 30 years, only recently has it spread

  5. What can the programming language Rust do for astrophysics?

    Science.gov (United States)

    Blanco-Cuaresma, Sergi; Bolmont, Emeline

    2017-06-01

    The astrophysics community uses different tools for computational tasks such as complex systems simulations, radiative transfer calculations or big data. Programming languages like Fortran, C or C++ are commonly present in these tools and, generally, the language choice was made based on the need for performance. However, this comes at a cost: safety. For instance, a common source of error is the access to invalid memory regions, which produces random execution behaviors and affects the scientific interpretation of the results. In 2015, Mozilla Research released the first stable version of a new programming language named Rust. Many features make this new language attractive for the scientific community, it is open source and it guarantees memory safety while offering zero-cost abstraction. We explore the advantages and drawbacks of Rust for astrophysics by re-implementing the fundamental parts of Mercury-T, a Fortran code that simulates the dynamical and tidal evolution of multi-planet systems.

  6. Protective, curative and eradicative activities of fungicides against grapevine rust

    Directory of Open Access Journals (Sweden)

    Francislene Angelotti

    2014-01-01

    Full Text Available The protective, eradicative and curative activities of the fungicides azoxystrobin, tebuconazole, pyraclostrobin+metiram, and ciproconazole against grapevine rust, were determined in greenhouse. To evaluate the protective activity, leaves of potted ´Niagara´ (Vitis labrusca vines were artificially inoculated with an urediniospore suspension of Phakopsora euvitis four, eight or forteen days after fungicidal spray; and to evaluate the curative and eradicative activities, leaves were sprayed with fungicides two, four or eight days after inoculation. Disease severity was assessed 14 days after each inoculation. All tested fungicides present excellent preventive activity against grapevine rust; however, tebuconazole and ciproconazole provide better curative activity than azoxystrobin and pyraclostrobin+metiram. It was observed also that all tested fungicides significantly reduced the germination of urediniospore produced on sprayed leaves.

  7. Katome: de novo DNA assembler implemented in rust

    Science.gov (United States)

    Neumann, Łukasz; Nowak, Robert M.; Kuśmirek, Wiktor

    2017-08-01

    Katome is a new de novo sequence assembler written in the Rust programming language, designed with respect to future parallelization of the algorithms, run time and memory usage optimization. The application uses new algorithms for the correct assembly of repetitive sequences. Performance and quality tests were performed on various data, comparing the new application to `dnaasm', `ABySS' and `Velvet' genome assemblers. Quality tests indicate that the new assembler creates more contigs than well-established solutions, but the contigs have better quality with regard to mismatches per 100kbp and indels per 100kbp. Additionally, benchmarks indicate that the Rust-based implementation outperforms `dnaasm', `ABySS' and `Velvet' assemblers, written in C++, in terms of assembly time. Lower memory usage in comparison to `dnaasm' is observed.

  8. RESEARCH ARTICLE Genetics and mapping of a new leaf rust ...

    Indian Academy of Sciences (India)

    3BL with SSR markers Xgwm114 and Xgwm547 flanking the gene at a distance of 28.3 cM and 6 cM, respectively. Based on nature of resistance and the chromosomal location, it is inferred that Selection G12 carries a new gene for leaf rust resistance, tentatively named as. LrSelG12. Key words:Wheat; alienintrogression ...

  9. The pine-oak rusts: How forest tree species connect

    Science.gov (United States)

    D. R. Vogler

    2008-01-01

    The pine-oak rust fungi, which live out their lives as pathogens on pines and oaks, have multiple spore states and complex life cycles. Because they can be severe pathogens of pines, much of what we know about them depends on how damaging they are to management of pine forests for timber, recreation, and ecosystem values. Widely distributed in North America, they are...

  10. The escalatory Red Queen: Population extinction and replacement following arms race dynamics in poplar rust.

    Science.gov (United States)

    Persoons, Antoine; Hayden, Katherine J; Fabre, Bénédicte; Frey, Pascal; De Mita, Stéphane; Tellier, Aurélien; Halkett, Fabien

    2017-04-01

    Host-parasite systems provide convincing examples of Red Queen co-evolutionary dynamics. Yet, a key process underscored in Van Valen's theory - that arms race dynamics can result in extinction - has never been documented. One reason for this may be that most sampling designs lack the breadth needed to illuminate the rapid pace of adaptation by pathogen populations. In this study, we used a 25-year temporal sampling to decipher the demographic history of a plant pathogen: the poplar rust fungus, Melampsora larici-populina. A major adaptive event occurred in 1994 with the breakdown of R7 resistance carried by several poplar cultivars widely planted in Western Europe since 1982. The corresponding virulence rapidly spread in M. larici-populina populations and nearly reached fixation in northern France, even on susceptible hosts. Using both temporal records of virulence profiles and temporal population genetic data, our analyses revealed that (i) R7 resistance breakdown resulted in the emergence of a unique and homogeneous genetic group, the so-called cultivated population, which predominated in northern France for about 20 years, (ii) selection for Vir7 individuals brought with it multiple other virulence types via hitchhiking, resulting in an overall increase in the population-wide number of virulence types and (iii) - above all - the emergence of the cultivated population superseded the initial population which predominated at the same place before R7 resistance breakdown. Our temporal analysis illustrates how antagonistic co-evolution can lead to population extinction and replacement, hence providing direct evidence for the escalation process which is at the core of Red Queen dynamics. © 2016 John Wiley & Sons Ltd.

  11. Evidence for Systemic Infection by Puccinia horiana, Causal Agent of Chrysanthemum White Rust, in Chrysanthemum.

    Science.gov (United States)

    Bonde, M R; Murphy, C A; Bauchan, G R; Luster, D G; Palmer, C L; Nester, S E; Revell, J M; Berner, D K

    2015-01-01

    Puccinia horiana, causal agent of the disease commonly known as chrysanthemum white rust (CWR), is a quarantine-significant fungal pathogen of chrysanthemum in the United States and indigenous to Asia. The pathogen was believed to have been eradicated in the United States but recently reappeared on several occasions in northeastern United States. The objective of the study presented here was to determine whether P. horiana could systemically infect chrysanthemum plants, thus providing a means of survival through winters. Scanning and transmission electron microscopy revealed the development of P. horiana on the surface and within leaves, stems, or crowns of inoculated chrysanthemum plants artificially exposed to northeastern U.S. winter temperatures. P. horiana penetrated leaves directly through the cuticle and then colonized the mesophyll tissue both inter- and intracellularly. An electron-dense material formed at the interface between fungal and host mesophyll cells, suggesting that the pathogen adhered to the plant cells. P. horiana appeared to penetrate mesophyll cell walls by enzymatic digestion, as indicated by the absence of deformation lines in host cell walls at penetration sites. The fungus was common in vascular tissue within the infected crown, often nearly replacing the entire contents of tracheid cell walls. P. horiana frequently passed from one tracheid cell to an adjacent tracheid cell by penetration either through pit pairs or nonpitted areas of the cell walls. Individual, presumed, fungal cells in mature tracheid cells of the crown and stems arising from infected crowns suggested that the pathogen might have been moving at least partially by means of the transpiration stream. The demonstration that chrysanthemum plants can be systemically infected by P. horiana suggests that additional disease control measures are required to effectively control CWR.

  12. TaRAR1 and TaSGT1 associate with TaHsp90 to function in bread wheat (Triticum aestivum L.) seedling growth and stripe rust resistance.

    Science.gov (United States)

    Wang, Guan-Feng; Fan, Renchun; Wang, Xianping; Wang, Daowen; Zhang, Xiangqi

    2015-04-01

    RAR1 and SGT1 are important co-chaperones of Hsp90. We previously showed that TaHsp90.1 is required for wheat seedling growth, and that TaHsp90.2 and TaHsp90.3 are essential for resistance (R) gene mediated resistance to stripe rust fungus. Here, we report the characterization of TaRAR1 and TaSGT1 genes in bread wheat. TaRAR1 and TaSGT1 each had three homoeologs, which were located on wheat groups 2 and 3 chromosomes, respectively. Strong inhibition of seedling growth was observed after silencing TaSGT1 but not TaRAR1. In contrast, decreasing the expression of TaRAR1 or TaSGT1 could all compromise R gene mediated resistance to stripe rust fungus infection. Protein-protein interactions were found among TaRAR1, TaSGT1 and TaHsp90. The N-terminus of TaHsp90, the CHORD-I and CHORD-II domains of TaRAR1 and the CS domain of TaSGT1 may be instrumental for the interactions among the three proteins. Based on this work and our previous study on TaHsp90, we speculate that the TaSGT1-TaHsp90.1 interaction is important for maintaining bread wheat seedling growth. The TaRAR1-TaSGT1-TaHsp90.2 and TaRAR1-TaSGT1-TaHsp90.3 interactions are involved in controlling the resistance to stripe rust disease. The new information obtained here should aid further functional investigations of TaRAR1-TaSGT1-TaHsp90 complexes in regulating bread wheat growth and disease resistance.

  13. The genome sequence and effector complement of the flax rust pathogen Melampsora lini.

    Science.gov (United States)

    Nemri, Adnane; Saunders, Diane G O; Anderson, Claire; Upadhyaya, Narayana M; Win, Joe; Lawrence, Gregory J; Jones, David A; Kamoun, Sophien; Ellis, Jeffrey G; Dodds, Peter N

    2014-01-01

    Rust fungi cause serious yield reductions on crops, including wheat, barley, soybean, coffee, and represent real threats to global food security. Of these fungi, the flax rust pathogen Melampsora lini has been developed most extensively over the past 80 years as a model to understand the molecular mechanisms that underpin pathogenesis. During infection, M. lini secretes virulence effectors to promote disease. The number of these effectors, their function and their degree of conservation across rust fungal species is unknown. To assess this, we sequenced and assembled de novo the genome of M. lini isolate CH5 into 21,130 scaffolds spanning 189 Mbp (scaffold N50 of 31 kbp). Global analysis of the DNA sequence revealed that repetitive elements, primarily retrotransposons, make up at least 45% of the genome. Using ab initio predictions, transcriptome data and homology searches, we identified 16,271 putative protein-coding genes. An analysis pipeline was then implemented to predict the effector complement of M. lini and compare it to that of the poplar rust, wheat stem rust and wheat stripe rust pathogens to identify conserved and species-specific effector candidates. Previous knowledge of four cloned M. lini avirulence effector proteins and two basidiomycete effectors was used to optimize parameters of the effector prediction pipeline. Markov clustering based on sequence similarity was performed to group effector candidates from all four rust pathogens. Clusters containing at least one member from M. lini were further analyzed and prioritized based on features including expression in isolated haustoria and infected leaf tissue and conservation across rust species. Herein, we describe 200 of 940 clusters that ranked highest on our priority list, representing 725 flax rust candidate effectors. Our findings on this important model rust species provide insight into how effectors of rust fungi are conserved across species and how they may act to promote infection on their

  14. The genome sequence and effector complement of the flax rust pathogen Melampsora lini

    Directory of Open Access Journals (Sweden)

    Adnane eNemri

    2014-03-01

    Full Text Available Rust fungi cause serious yield reductions on crops, including wheat, barley, soybean, coffee, and represent real threats to global food security. Of these fungi, the flax rust pathogen Melampsora lini has been developed extensively over the past 80 years as a model to understand the molecular mechanisms that underpin pathogenesis. During infection, M. lini secretes virulence effectors to promote disease. The number of these effectors, their function and their degree of conservation across rust fungal species is unknown. To assess this, we sequenced and assembled de novo the genome of M. lini isolate CH5 into 21,130 scaffolds spanning 189 Mbp (scaffold N50 of 31 kbp. Global analysis of the DNA sequence revealed that repetitive elements, primarily retrotransposons, make up at least 45% of the genome. Using ab initio predictions, transcriptome data and homology searches, we identified 16,271 putative protein-coding genes. An analysis pipeline was then implemented to predict the effector complement of M. lini and compare it to that of the poplar rust, wheat stem rust and wheat stripe rust pathogens to identify conserved and species-specific effector candidates. Previous knowledge of four cloned M. lini avirulence effector proteins and two basidiomycete effectors was used to optimise parameters of the effector prediction pipeline. Markov clustering based on sequence similarity was performed to group effector candidates from all four rust pathogens. Clusters containing at least one member from M. lini were further analysed and prioritized based on features including expression in isolated haustoria and infected leaf tissue and conservation across rust species. Herein, we describe 200 of 940 clusters that ranked highest on our priority list, representing 725 flax rust candidate effectors. Our findings on this important model rust species provide insight into how effectors of rust fungi are conserved across species and how they may act to promote

  15. Assessment of imperfect detection of blister rust in whitebark pine within the Greater Yellowstone Ecosystem

    Science.gov (United States)

    Wright, Wilson J.; Irvine, Kathryn M.

    2017-01-01

    We examined data on white pine blister rust (blister rust) collected during the monitoring of whitebark pine trees in the Greater Yellowstone Ecosystem (from 2004-2015). Summaries of repeat observations performed by multiple independent observers are reviewed and discussed. These summaries show variability among observers and the potential for errors being made in blister rust status. Based on this assessment, we utilized occupancy models to analyze blister rust prevalence while explicitly accounting for imperfect detection. Available covariates were used to model both the probability of a tree being infected with blister rust and the probability of an observer detecting the infection. The fitted model provided strong evidence that the probability of blister rust infection increases as tree diameter increases and decreases as site elevation increases. Most importantly, we found evidence of heterogeneity in detection probabilities related to tree size and average slope of a transect. These results suggested that detecting the presence of blister rust was more difficult in larger trees. Also, there was evidence that blister rust was easier to detect on transects located on steeper slopes. Our model accounted for potential impacts of observer experience on blister rust detection probabilities and also showed moderate variability among the different observers in their ability to detect blister rust. Based on these model results, we suggest that multiple observer sampling continue in future field seasons in order to allow blister rust prevalence estimates to be corrected for imperfect detection. We suggest that the multiple observer effort be spread out across many transects (instead of concentrated at a few each field season) while retaining the overall proportion of trees with multiple observers around 5-20%. Estimates of prevalence are confounded with detection unless it is explicitly accounted for in an analysis and we demonstrate how an occupancy model can be used

  16. Aspectos biológicos y control químico de la roya del clavel (Uromyces caryophyllinus (SHRANK WINT en la Sabana de Bogotá

    Directory of Open Access Journals (Sweden)

    Cifuentes Yolanda

    1984-12-01

    Full Text Available Con el fin de determinar algunos de los aspectos biológicos de la roya clavel y para evaluar algunos fungicidas sistémicos y protector, una investigación se realizó bajo condiciones de laboratorio y en invernadero. El método más eficiente de la inoculación fue el spray de suspensión uredospore. Zineb, Oxicarboxin y Diclofluanid fueron los inhibidores más eficientes de la germinación uredospore. En los ensayos de invernadero, Oxicarboxin que parecía ser el mejor fungicida seguido por Triforina, Bitertanol, Diclofluanid, Zineb y Pyracarbolld. El Oxicarboxin fungicidas y Triforina aplicada a la solidaridad eran mucho mejores que pulverización foliar.In order to determine some of the biological aspects of the carnation rust and to evaluate some systemic and protectant fungicides, a research was done under laboratory and greenhouse conditions. The most efficient method of inoculation was the spray of uredospore suspension. Zineb, Oxicarboxin and Diclofluanid were the most efficient Inhibitors of uredospore germination. In the greenhouse trials, Oxicarboxin appeared to be the best fungicide followed by Triforine, Bitertanol, Diclofluanid, Zineb and Pyracarbolld. The fungicides Oxicarboxin and Triforine applied to the soli were much better than foliar spray.

  17. InIdentification and characterization of pathotypes in Puccinia horiana, a rust pathogen of Chrysanthemum x morifolium

    NARCIS (Netherlands)

    Backer, de M.; Alaei, H.; Bockstaele, van E.; Roldan-Ruiz, I.; Lee, van der T.; Maes, M.; Heungens, K.

    2011-01-01

    Puccinia horiana is the causal agent of chrysanthemum white rust or Japanese rust. This microcyclic autoecious rust has a quarantine status and can cause major damage in the commercial production of Chrysanthemum x morifolium. Given the international and often trans-continental production of

  18. Evaluation of Soybean Germplasm for Resistance to Soybean Rust in Vietnam

    Science.gov (United States)

    Soybean rust, caused by Phakopsora pachyrhizi Sydow, is a severe foliar disease of soybean [Glycine max (L.) Merr.] that occurs throughout most soybean producing regions of the world. Soybean rust may be managed with fungicides, but the utilization of soybean cultivars that are resistant to the path...

  19. Effect of orange rust on sugarcane breeding program at canal Point

    Science.gov (United States)

    Orange rust of sugarcane (Saccharum spp. hybrids), caused by Puccinia kuehnii (W. Krüger) E.J. Butler, appeared in the Western Hemisphere ten years ago. Orange rust substantially reduces yields in susceptible sugarcane genotypes. Majority of the commercial cultivars were susceptible at the time of o...

  20. Detection of wheat stem rust race RRTTF in Ecuador in 2016

    Science.gov (United States)

    Wheat stem rust is a devastating disease that has incited numerous severe epidemics resulting in extreme yield losses over the past century. Stem rust infection in plots of wheat line UC11075, known to carry the Sr38 resistance gene, was severe in February 2016 in a nursery at the Instituto Nacional...

  1. A new rust disease on wild coffee (Psychotria nervosa) caused by Puccinia mysuruensis sp. nov

    Science.gov (United States)

    Psychotria nervosa, commonly called wild coffee (Rubiaceae) is an important ethno-medicinal plant in India. In 2010 a new rust disease of P. nervosa was observed in three regions of Mysore District, Karnataka (India) with disease incidence ranging from 58% to 63%. Typical symptoms of rust disease we...

  2. Real-time PCR detection of Puccinia chrysanthemi causing brown rust of chrysanthemum

    Science.gov (United States)

    Fungi responsible for rust diseases are among the most challenging organisms to identify, as many identification keys are based on host identity. In the U.S., numerous rust fungi are quarantine-significant plant pathogens. As such, accurate identification is crucial to prevent the inadvertent introd...

  3. Rust urine after intense hand drumming is caused by extracorpuscular hemolysis.

    Science.gov (United States)

    Tobal, Diego; Olascoaga, Alicia; Moreira, Gabriela; Kurdián, Melania; Sanchez, Fernanda; Roselló, Maria; Alallón, Walter; Martinez, Francisco Gonzalez; Noboa, Oscar

    2008-07-01

    During Carnival, groups of > or =60 drummers go drumming with their hands and marching for periods of 2 to 4 h. The objective of this study was to determine the frequency and type of urinary abnormalities after candombe drumming and to evaluate possible pathogenic mechanisms. For analysis of pathogenic mechanisms, a group of individuals were prospectively evaluated before and after candombe drumming. Candombe drummers were recruited in January 2006, 1 wk before prolonged drumming. After clinical evaluation, urine and blood samples were obtained before and immediately after drumming. Forty-five healthy individuals (four women and 41 men), median age 31 yr (14 to 56), were evaluated. Predrumming urine and plasma samples were obtained for 30 individuals. Nineteen (42%) of 45 had a previous history of rust urine emission temporally related with candombe drumming. After drumming, 18 of 26 showed urine abnormalities; six of 26 showed rust urine, eight of 26 had microhematuria, and seven of 26 had proteinuria >1 g/L. The candombe drummers who showed rust urine after heavy drumming presented significantly higher levels of lactate dehydrogenase and total bilirubin when compared with those without urine abnormalities. Haptoglobin was significantly lower in the rust urine group. Fragmented red cells were observed in the blood smear of individuals with rust urine. Rust urine after drumming was associated with previous episodes of rust urine and glucosuria. Taken together, these data confirm that rust urine is caused by extracorpuscular hemolysis.

  4. Effective genes for resistance to stripe rust and virulence of Puccinia ...

    African Journals Online (AJOL)

    Effective genes for resistance to stripe rust and virulence of Puccinia striiformis f. sp. tritici in Pakistan. H Bux, M Ashraf, X Chen, S Mumtaz. Abstract. Virulence patterns of wheat stripe rust were studied under the field conditions across four environmentally different locations: Quaid-i-Azam University (Islamabad), Pirsabak ...

  5. Genome-wide association mapping of crown rust resistance in oat elite germplasm

    Science.gov (United States)

    Oat crown rust, caused by Puccinia coronata f. sp. avenae, is a major constraint to oat production in many parts of the world. In this first comprehensive multi-environment genome-wide association map of oat crown rust, we used 2,972 SNPs genotyped on 631 oat lines for association mapping of quantit...

  6. Effect of fungicide on the development of wheat stem rust and yield ...

    African Journals Online (AJOL)

    Stem rust caused by Puccinia graminis f.sp tritici Erik. & E. Henn. is a highly destructive disease of wheat (Triticum aestivum L.). The effects of fungicide application on stem rust (Puccinia graminis tritici) epidemics and yield of three bread wheat varieties varying in reaction to the disease were studied in two major wheat ...

  7. Preliminary evaluation of daylily cultivars for rust resistance in a landscaping setting

    Science.gov (United States)

    A large, established landscape collection of 575 newer cultivars was evaluated for daylily rust which had not been sprayed with fungicides to prevent infection during 2013. The warm, damp summer of 2013 was ideal for spread of daylily rust. A total of 119 of the 575 cultivars received a median ratin...

  8. Genetics of adult plant stripe rust resistance in CSP44, a selection ...

    Indian Academy of Sciences (India)

    Wheat line CSP44, a selection from an Australian bread wheat cultivar Condor, has shown resistance to stripe rust in India since the last twenty years. Seedlings and adult plants of CSP44 showed susceptible infection types against stripe rust race 46S119 but displayed average terminal disease severity of 2.67 on adult ...

  9. Screening conventional fungicides...control of blister rust on sugar pine in California

    Science.gov (United States)

    Clarence R. Quick

    1967-01-01

    After 5 years, 4 of 14 fungicides tested showed varying pr of development into satisfactory direct control of blister rust. Little promise of systemic control was found. Trees treated were second-growth sugar pine in a mixed conifer forest in eastern Shasta County, California, where blister rust has been intensifying for many years. Most trees received basal-stem...

  10. Wheat stem rust in South Africa: Current status and future research ...

    African Journals Online (AJOL)

    . In South Africa, stem rust caused by Puccinia graminis Pers. f. sp. tritici. Eriks. & E. Henn. (Pgt) is an important disease of wheat. Records of stem rust occurrence in South Africa date back to the late 1720's, when it was first discovered in the ...

  11. Genetics of leaf and stripe rust resistance in a bread wheat cultivar ...

    Indian Academy of Sciences (India)

    Leaf rust caused by Puccinia triticina (=P. recondita Rober- age ex Desmaz f. sp. tritici Eriks and E. Henn.) and stripe rust caused by P. striiformis Westend f. sp. tritici are the major foliar diseases of wheat, resulting in yield loss all over the world (Eversmeyer and Browder 1974; Kolmer 1996). The wheat cultivars become ...

  12. Genetic analysis and location of gene for resistance to stripe rust in ...

    Indian Academy of Sciences (India)

    Strubes Dickkopf is the sixth differential in the world set for wheat stripe (yellow) rust. It is very important to clarify its genetic character of resistance to stripe rust and to develop the molecular markers linked to resistance genes. The NIL Taichung 29*6/Strubes Dickkopf, which was obtained by Strubes Dickkopf as the gene ...

  13. Introgression of a leaf rust resistance gene from Aegilops caudata to ...

    Indian Academy of Sciences (India)

    Abstract. Rusts are the most important biotic constraints limiting wheat productivity worldwide. Deployment of cultivars with broad spectrum rust resistance is the only environmentally viable option to combat these diseases. Identification and introgression of novel sources of resistance is a continuous process to combat the ...

  14. Identification of rust resistance genes Lr10 and Sr9a in Pakistani ...

    African Journals Online (AJOL)

    Wheat (Triticum aestivum L.) rusts are the most widespread and destructive among all other diseases of wheat because of their wide distribution, and their capacity to form new races that can attack previously resistant cultivars which result in serious yield losses. Stem rust caused by Puccinia graminis f. sp. tritici and leaf of ...

  15. Using Bayleton (Triadimefon) to Control Fusiform Rust in Pine Tree Nurseries

    Science.gov (United States)

    G.A. Snow; S.J. Rowan; J.P. Jones; W. D. Kelley; J.G. Mexal

    1979-01-01

    Bayletor® was field-tested for fusiform rust control at eight pine tree nurseries during the spring of 1978. Four to six foliar sprays of this systemic fungicide were as effective as ferbam sprayed 16 to 36 times. Seed treatment with Bayleton reduced infection levels but did not significantly improve rust control in plots sprayed with Bayleton. At high rates, Bayleton...

  16. Genetics of leaf rust resistance in the hard red winter wheat cultivars Santa Fe and Duster

    Science.gov (United States)

    Leaf rust caused by Puccinia triticina is a common and important disease of hard red winter wheat in the Great Plains of the United States. The hard red winter wheat cultivars 'Santa Fe' and 'Duster' have had effective leaf rust resistance since their release in 2003 and 2006, respectively. Both cul...

  17. Barberry rust survey – developing tools for diagnosis, analysis and data management

    DEFF Research Database (Denmark)

    Justesen, Annemarie Fejer; Hansen, Jens Grønbech; Hovmøller, Mogens Støvring

    a rust survey was initiated. The aim was to 1) develop a surveillance protocol 2) develop molecular diagnostic tools for identifying Puccinia spp. from aecial samples, and 3) develop a data management and display system of results as part of the Wheat Rust ToolBox (http....... arrhenatheri and P. striiformoides on barberry species. Survey and DNA sample maps with species designation were displayed in the Wheat Rust ToolBox. The future aim is to integrate barberry rust survey data based on molecular diagnostics and infection assays from research groups world-wide in order to gain......Barberry (Berberis spp.) may serve as alternate host of several Puccinia species including Puccinia graminis and P. striiformis causing stem and yellow rust on cereals and grasses, respectively. In order to study the importance of barberry in the epidemiology of Puccinia species in the CWANA region...

  18. OCCURRENCE IN THE SOIL AND DISPERSAL OF Lecanicillium lecanii, A FUNGAL PATHOGEN OF THE GREEN COFFEE SCALE (Coccus viridis AND COFFEE RUST (Hemileia vastatrix

    Directory of Open Access Journals (Sweden)

    Doug William Jackson

    2012-08-01

    Full Text Available The fungus Lecanicillium lecanii attacks the green scale (Coccus viridis, a pest of coffee, and is also a hyperparasite of coffee rust (Hemileia vastatrix. Knowledge of the epizootiology of this fungus is potentially important for conservation biological control in coffee agroecosystems. The presence of viable propagules of L. lecanii in the soil, a possible environmental reservoir, was assessed using two baiting methods: the standard Galleria mellonella bait method and a C. viridis bait method. Infectious propagules of L. lecanii were detected in soil samples taken from a 45 ha study plot, both nearby and far from recent epizootics of L. lecanii. To test the potential for the transmission of L. lecanii conidia from the soil via rain splash or wind, coffee seedlings with populations of C. viridis were placed near L. lecanii-inoculated soil and then subjected to artificial rain and wind treatments. Rain splash was shown to be a potential transmission mechanism. Dispersal of L. lecanii conidia by the ant Azteca instabilis was tested using field and laboratory ant-exclusion experiments. Azteca instabilis was shown to transport conidia of L. lecanii; however, dispersal by A. instabilis may not be important under field conditions.

  19. Construction and characterization of a full-length cDNA library for the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici

    Directory of Open Access Journals (Sweden)

    Chen Xianming

    2007-06-01

    Full Text Available Abstract Background Puccinia striiformis is a plant pathogenic fungus causing stripe rust, one of the most important diseases on cereal crops and grasses worldwide. However, little is know about its genome and genes involved in the biology and pathogenicity of the pathogen. We initiated the functional genomic research of the fungus by constructing a full-length cDNA and determined functions of the first group of genes by sequence comparison of cDNA clones to genes reported in other fungi. Results A full-length cDNA library, consisting of 42,240 clones with an average cDNA insert of 1.9 kb, was constructed using urediniospores of race PST-78 of P. striiformis f. sp. tritici. From 196 sequenced cDNA clones, we determined functions of 73 clones (37.2%. In addition, 36 clones (18.4% had significant homology to hypothetical proteins, 37 clones (18.9% had some homology to genes in other fungi, and the remaining 50 clones (25.5% did not produce any hits. From the 73 clones with functions, we identified 51 different genes encoding protein products that are involved in amino acid metabolism, cell defense, cell cycle, cell signaling, cell structure and growth, energy cycle, lipid and nucleotide metabolism, protein modification, ribosomal protein complex, sugar metabolism, transcription factor, transport metabolism, and virulence/infection. Conclusion The full-length cDNA library is useful in identifying functional genes of P. striiformis.

  20. First report of the white pine blister rust fungus, Cronartium ribicola, infecting Ribes inerme in north-central Utah

    Science.gov (United States)

    D. R. Vogler; B. W. Geils; K. Coats

    2017-01-01

    Cronartium ribicola Fisch. has not been found infecting any of the five-needle white pines (Pinus subgenus Strobus) in Utah, despite being established on both white pine and Ribes hosts in the other 10 western states, defined as those west of the 102° meridian.

  1. [Cloning and expression of a class II chitin synthase gene PstChs II from the rust fungus Puccinia striiformis].

    Science.gov (United States)

    Liang, Xiaofei; Liu, Bo; Zhu, Lin; Zhang, Xiaoyu; Wang, Xiaojie; Huang, Lili; Kang, Zhensheng

    2009-12-01

    To clone the chitin synthase gene PstChs II from Puccinia striiformis and to analyze its expression pattern. We isolated the cDNA and genomic DNA of PstChs II via RT-PCR and PCR,analyzed the sequences with different bioinformatic tools, characterized the gene expression pattern via real-time PCR. The coding region of PstChs II (Genbank accession no: GQ329851), interrupted by 15 introns, corresponded to a 2727 bp open reading frame encoding 908 amino acids. PstChs II showed a highest 94% similarity to PgtChs II from Puccinia graminis. PstChs II had 7 transmembrance regions and several conserved chitin synthase domains and motifs such as "QXRRW", "GXGPL" and "DXD". PstChs II belonged to the class II sub-family and had a closer phylogenetic relationship to its homologs from basidiomycetes than those from ascomycetes. PstChs II expression level increased by 10-fold at the urediospore germination stage. PstChs II might be involved in the cell wall synthesis during the germ tube elongation process. The cloning and expression analysis of PstChs II served as a good foundation for further analyzing the role of this gene in the pathogenesis process.

  2. Recovery and virulence phenotyping of the historic 'Stubbs Collection' of the yellow rust fungus Puccinia striiformis from wheat

    DEFF Research Database (Denmark)

    Thach, T.; Ali, S.; Justesen, A. F.

    2015-01-01

    undetected virulence. A new method for recovery using an airbrush sprayer and Novec™ 7100 for inoculating the host plants was highly successful. Ninety-six percent of 231 isolates were recovered. Virulence phenotyping was done using differential sets of wheat genotypes representing specific-resistance genes...... of updated and more informative wheat-differential sets. The remaining 35 isolates showed discrepancies for one or more virulences when compared with past results. Additional virulences corresponding to Yr17, Yr25 and Yr27, respectively, which were not assayed originally, were discovered. The value...

  3. The role of green rust in the environment: a review O papel do green rust no ambiente

    Directory of Open Access Journals (Sweden)

    Lucia H. G. Chaves

    2005-06-01

    Full Text Available Iron(II-iron(III hydroxy-salts known as green rusts (GRs initially were identified and studied as corrosion products of steel and iron. Recently they were discovered as minerals present in hydromorphic soils and sediments. Different studies have suggested that GRs, due to their high reactivity, play an important role in the fate and transport of many contaminants in suboxic soils, sediments and aquifers where microbial reduction rates are limited by low carbon content. Also, GRs have considerable potential for applications such as water-purification processes and gas adsorbents. However, as GRs are only a transient state during the reduction of ferric iron and are converted to more stable forms, it is still necessary to continue studies about their behavior.Hidróxidos de ferro (II-ferro(III conhecidos como "green rust" (GR, inicialmente foram identificados e estudados como sendo os produtos provenientes da corrosão do aço e do ferro. Recentemente esses hidróxidos foram encontrados na forma mineral em solos hidromórficos e em sedimentos. Devido a sua alta reatividade, muitos trabalhos têm mostrado que esses hidróxidos desempenham um importante papel no destino e transporte de muitos contaminantes em solos subóxicos, sedimentos e aqüíferos, onde a taxa de redução microbiana é limitada pelo baixo conteúdo de carbono. Os "green rusts" também podem ser utilizados nos processos de purificação de águas e como adsorventes de gases. Entretanto, como GR são considerados uma fase transitória durante a redução do íon férrico e são, rapidamente, convertidos para formas mais estáveis, é necessário que os estudos sobre seu comportamento continuem.

  4. Disease Control Efficacy of the Extract of Magnolia officinalis against Perilla and Zoysiagrass Rusts

    Directory of Open Access Journals (Sweden)

    Mi-Young Yoon

    2013-03-01

    Full Text Available Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. Rusts can affect a variety of plants. Development of new effective and environmentally benign agents against rusts is of great interest. In this study, we investigated the disease control efficacy of the emulsion concentrate (EC10 and wettable powder (WP20 type formulations of the extract of Magnolia officinalis (Magjia90; containing honokiol and magnolol at 90% against rust diseases of perilla and zoysiagrass in fields. The treatment of EC10 and WP20 of Magjia90 showed control values of 47.9% to 69.6% and Magjia90-WP20 reduced more effectively the development of rust symptoms on perilla plants than Magjia90-EC10. Magjia90-WP20 also highly suppressed zoysiagrass rust with control values of 65.7% to 80.5%. On the other hand, no harmful effect of Magjia90- EC10 and Magjia90-WP20 was observed on the perilla and zoysiagrass plants tested. The results strongly indicate that the extract of M. officinalis (Magjia90 can be used as a natural fungicide for the control of rust diseases.

  5. Factors contributing to seasonal fluctuations in rust severity on Ribes missouriense caused by Cronartium ribicola.

    Science.gov (United States)

    Newcomb, Maria; Upper, Christen D; Rouse, Douglas I

    2010-10-01

    Cronartium ribicola, causal agent of white pine blister rust, is a macrocyclic heteroecious rust that cycles between white pines and members of the genus Ribes, which are typically wild plants in North America. To improve predictability of inoculum available for infection of ecologically and commercially important white pines, this research was conducted to identify the factors that influence the development and persistence of uredinia and telia on Ribes in their natural habitats. Numbers of infectious C. ribicola rust lesions (with potentially sporulating rust sori) on tagged Ribes missouriense plants in the woods fluctuated during the season. Changes in numbers of infectious rust lesions were related to rain that occurred 13 days earlier. In field experiments, supplemental leaf wetness provided for 2 days on Ribes shoots resulted in the development of rust lesions more frequently than on control shoots. Viable inoculum and susceptible hosts were present, and the environment was the limiting factor for disease development. Lesion necrosis and leaf abscission contributed to decreases in numbers of infectious rust lesions. Higher lesion density was significantly related to earlier leaf abscission. Telial fruiting bodies occurred in low numbers from early June throughout the remainder of the season.

  6. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  7. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  8. QTL analysis of crown rust resistance in perennial ryegrass under conditions of natural and artificial infection

    DEFF Research Database (Denmark)

    Schejbel, Britt; Jensen, Louise Friis Bach; Xing, Yongzhong

    2007-01-01

    Crown rust is an economically devastating disease of perennial ryegrass. Both artificial crown rust inoculations, with the possibility of several selection cycles in one year, as well as marker-assisted selection can be used for more efficient breeding of new resistant cultivars. The objective...... as well as by artificial pathogen inoculations using a detached leaf assessment. The broad sense heritability values for the field, detached leaf and combined assays were 0.42, 0.56, and 0.64, respectively, indicating a good potential for selection for crown rust resistance. A total of six QTLs were...

  9. The effect of nitrogen application on the development of rusts on wheat varieties

    Directory of Open Access Journals (Sweden)

    M. E. Haggag

    2014-11-01

    Full Text Available The effect of four different levels of nitrogen fertilization on the severity of rusts on three local Egyptian wheat varieties have been investigated. Nitrogen fertilizer was at the rates 0, 40, 60, and 80 kg nitrogen per feddan. Data obtained indicated that resistance of the varieties did not change while percent severity of postules on susceptible, moderately susceptible and moderately resistant varieties was increased as the level of nitrogen fertilization increased. Heavy doses of nitrogen promoted the size and frequency of postules and hence the rust growth and predisposed the plants to higher infection with rusts.

  10. Metabolites from marine fungus Aspergillus sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; Rajmanickam, R.; DeSouza, L.

    Chemical examination of a methanolic extract of the marine fungus, Aspergillus sp., isolated from marine grass environment, yielded a steroid, ergosterol peroxide (1), and a mixture of known glyceride esters (2,3) of unsaturated fatty acids...

  11. U.S. National Fungus Collections

    Data.gov (United States)

    Department of Agriculture — The U.S. National Fungus Collections (BPI) are the “Smithsonian for fungi” and are the repository for over one million fungal specimens worldwide - the largest such...

  12. Multi-environment selection of small sieve snap beans reduces production constraints in East Africa and subtropical regions

    Science.gov (United States)

    Common bean rust caused by Uromyces appendiculatus, and heat stress lower the yield and quality of snap beans (Phaseolus vulgaris L.) in East Africa. Four snap bean breeding lines previously selected for broad-spectrum rust resistance (involving Ur-4 and Ur-11 rust genes) and heat tolerance followin...

  13. Evolution of Akaganeite in Rust Layers Formed on Steel Submitted to Wet/Dry Cyclic Tests

    Directory of Open Access Journals (Sweden)

    Haigang Xiao

    2017-11-01

    Full Text Available The evolution of akaganeite in rust layers strongly impacts the atmospheric corrosion behavior of steel during long-term exposure; however, the factors affecting the evolution of akaganeite and its mechanism of formation are vague. In this work, wet-dry cyclic corrosion tests were conducted to simulate long-term exposure. Quantitative X-ray diffraction analysis was employed to analyze variations in the relative amounts of akaganeite; scanning electron microscopy and electron probe microanalysis were used to study the migration of relevant elements in the rust layer, which could help elucidate the mechanism of akaganeite evolution. The results indicate that the fraction of akaganeite tends to decrease as the corrosion process proceeded, which is a result of the decrease in the amount of soluble chloride available and the ability of the thick rust layer to block the migration of relevant ions. This work also explores the location of akaganeite formation within the rust layer.

  14. Yr32 for resistance to stripe (yellow) rust present in the wheat cultivar Carstens V

    DEFF Research Database (Denmark)

    Eriksen, L.; Afshari, F.; Christiansen, M.J.

    2004-01-01

    Stripe or yellow rust of wheat, caused by Puccinia striiformis f. sp. tritici, is an important disease in many wheat-growing regions of the world. A number of major genes providing resistance to stripe rust have been used in breeding, including one gene that is present in the differential tester...... Carstens V. The objective of this study was to locate and map a stripe rust resistance gene transferred from Carstens V to Avocet S and to use molecular tools to locate a number of genes segregating in the cross Savannah/Senat. One of the genes present in Senat was predicted to be a gene that is present...... in Carstens V. For this latter purpose, stripe rust response data from both seedling and field tests on a doubled haploid population consisting of 77 lines were compared to an available molecular map for the same lines using a non-parametric quantitative trait loci (QTL) analysis. Results obtained in Denmark...

  15. A dynamic, web-based resource to identify rust fungi (Pucciniales in southern Africa

    Directory of Open Access Journals (Sweden)

    Alistair R. McTaggart

    2017-09-01

    Full Text Available Rust fungi (Pucciniales are some of the most important plant pathogens that cause diseases of agricultural and tree crops. There are approximately 8,000 described species worldwide. The rust fungi of South Africa were extensively studied by Ethel M. Doidge (1887 – 1965, who listed 468 species. Many nomenclatural and taxonomic changes, together with the discovery of new species and incursions of exotic species, have subsequently outdated Doidge’s monograph. To address this problem, we have developed an interactive Lucid key for the identification of 50 species of rust fungi in 17 genera from countries in southern Africa. The key is dynamic and may be updated in real-time. The Lucid key provides a platform to progressively provide descriptions and images for all rust fungi in southern Africa. Plant pathologists and mycologists are invited to participate in the development of this resource.

  16. Life cycle and genetic diversity of willow rusts (Melampsora spp. in Europe

    Directory of Open Access Journals (Sweden)

    Joanna Ciszewska-Marciniak

    2012-12-01

    Full Text Available The paper is a review of classical and recent studies on willow rusts in Europe, with special reference to short rotation coppice willows used for biomass production, such as common osier willow (Salix viminalis L.. The review presents the taxonomic classification of rust fungi from the genus Melampsora spp. We present a list of telial hosts (genus Salix as well as aecial hosts for different rust species. The life cycle of this fungal pathogen is described in detail from the epidemiological and genetic point of view. The DNA polymorphism of M. lariciepitea, the rust species most responsible for severe yield losses of plant biomass, is characterised based on RAPD, AFLP and RFLP-PCR methods.

  17. Molecular tagging of a novel rust resistance gene R(12) in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Gong, L; Hulke, B S; Gulya, T J; Markell, S G; Qi, L L

    2013-01-01

    Sunflower production in North America has recently suffered economic losses in yield and seed quality from sunflower rust (Puccinia helianthi Schwein.) because of the increasing incidence and lack of resistance to new rust races. RHA 464, a newly released sunflower male fertility restorer line, is resistant to both of the most predominant and most virulent rust races identified in the Northern Great Plains of the USA. The gene conditioning rust resistance in RHA 464 originated from wild Helianthus annuus L., but has not been molecularly marked or determined to be independent from other rust loci. The objectives of this study are to identify molecular markers linked to the rust resistance gene and to investigate the allelism of this gene with the unmapped rust resistance genes present in HA-R6, HA-R8 and RHA 397. Virulence phenotypes of seedlings for the F(2) population and F(2:3) families suggested that a single dominant gene confers rust resistance in RHA 464, and this gene was designated as R(12). Bulked segregant analysis identified ten markers polymorphic between resistant and susceptible bulks. In subsequent genetic mapping, the ten markers covered 33.4 cM of genetic distance on linkage group 11 of sunflower. A co-dominant marker CRT275-11 is the closest marker distal to R(12) with a genetic distance of 1.0 cM, while ZVG53, a dominant marker linked in the repulsion phase, is proximal to R(12) with a genetic distance of 9.6 cM. The allelism test demonstrated that R(12) is not allelic to the rust resistance genes in HA-R6, HA-R8 and RHA 397, and it is also not linked to any previously mapped rust resistance genes. Discovery of the R(12) novel rust resistance locus in sunflower and associated markers will potentially support the molecular marker-assisted introgression and pyramiding of R(12) into sunflower breeding lines.

  18. 16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

    Science.gov (United States)

    2010-01-01

    ... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant,” etc. (a) It is unfair or deceptive to: (1) Use the terms “corrosion proof,” “noncorrosive... the product will be immune from rust and other forms of corrosion during the life expectancy of the...

  19. Genetics and mapping of a new leaf rust resistance gene in Triticum ...

    Indian Academy of Sciences (India)

    AMIT KUMAR SINGH

    The leaf rust resistance gene was mapped to chromosome 3BL with SSR markers Xgwm114 and Xgwm547 flanking the gene at a distance of 28.3 cM and 6 cM, respectively. Based on the nature of resistance and chromosomal location, it is inferred that. Selection G12 carries a new gene for leaf rust resistance, tentatively ...

  20. Identification of Putative Coffee Rust Mycoparasites via Single-Molecule DNA Sequencing of Infected Pustules.

    Science.gov (United States)

    James, Timothy Y; Marino, John A; Perfecto, Ivette; Vandermeer, John

    2015-11-13

    The interaction of crop pests with their natural enemies is a fundament to their control. Natural enemies of fungal pathogens of crops are poorly known relative to those of insect pests, despite the diversity of fungal pathogens and their economic importance. Currently, many regions across Latin America are experiencing unprecedented epidemics of coffee rust (Hemileia vastatrix). Identification of natural enemies of coffee rust could aid in developing management strategies or in pinpointing species that could be used for biocontrol. In the present study, we characterized fungal communities associated with coffee rust lesions by single-molecule DNA sequencing of fungal rRNA gene bar codes from leaf discs (≈28 mm(2)) containing rust lesions and control discs with no rust lesions. The leaf disc communities were hyperdiverse in terms of fungi, with up to 69 operational taxonomic units (putative species) per control disc, and the diversity was only slightly reduced in rust-infected discs, with up to 63 putative species. However, geography had a greater influence on the fungal community than whether the disc was infected by coffee rust. Through comparisons between control and rust-infected leaf discs, as well as taxonomic criteria, we identified 15 putative mycoparasitic fungi. These fungi are concentrated in the fungal family Cordycipitaceae and the order Tremellales. These data emphasize the complexity of diverse fungi of unknown ecological function within a leaf that might influence plant disease epidemics or lead to the development of species for biocontrol of fungal disease. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  1. Identification of Putative Coffee Rust Mycoparasites via Single-Molecule DNA Sequencing of Infected Pustules

    OpenAIRE

    James, Timothy Y.; Marino, John A.; Perfecto, Ivette; Vandermeer, John

    2016-01-01

    The interaction of crop pests with their natural enemies is a fundament to their control. Natural enemies of fungal pathogens of crops are poorly known relative to those of insect pests, despite the diversity of fungal pathogens and their economic importance. Currently, many regions across Latin America are experiencing unprecedented epidemics of coffee rust (Hemileia vastatrix). Identification of natural enemies of coffee rust could aid in developing management strategies or in pinpointing s...

  2. Using hierarchical clustering of secreted protein families to classify and rank candidate effectors of rust fungi.

    Science.gov (United States)

    Saunders, Diane G O; Win, Joe; Cano, Liliana M; Szabo, Les J; Kamoun, Sophien; Raffaele, Sylvain

    2012-01-01

    Rust fungi are obligate biotrophic pathogens that cause considerable damage on crop plants. Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, and Melampsora larici-populina, the poplar leaf rust pathogen, have strong deleterious impacts on wheat and poplar wood production, respectively. Filamentous pathogens such as rust fungi secrete molecules called disease effectors that act as modulators of host cell physiology and can suppress or trigger host immunity. Current knowledge on effectors from other filamentous plant pathogens can be exploited for the characterisation of effectors in the genome of recently sequenced rust fungi. We designed a comprehensive in silico analysis pipeline to identify the putative effector repertoire from the genome of two plant pathogenic rust fungi. The pipeline is based on the observation that known effector proteins from filamentous pathogens have at least one of the following properties: (i) contain a secretion signal, (ii) are encoded by in planta induced genes, (iii) have similarity to haustorial proteins, (iv) are small and cysteine rich, (v) contain a known effector motif or a nuclear localization signal, (vi) are encoded by genes with long intergenic regions, (vii) contain internal repeats, and (viii) do not contain PFAM domains, except those associated with pathogenicity. We used Markov clustering and hierarchical clustering to classify protein families of rust pathogens and rank them according to their likelihood of being effectors. Using this approach, we identified eight families of candidate effectors that we consider of high value for functional characterization. This study revealed a diverse set of candidate effectors, including families of haustorial expressed secreted proteins and small cysteine-rich proteins. This comprehensive classification of candidate effectors from these devastating rust pathogens is an initial step towards probing plant germplasm for novel resistance components.

  3. Using hierarchical clustering of secreted protein families to classify and rank candidate effectors of rust fungi.

    Directory of Open Access Journals (Sweden)

    Diane G O Saunders

    Full Text Available Rust fungi are obligate biotrophic pathogens that cause considerable damage on crop plants. Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, and Melampsora larici-populina, the poplar leaf rust pathogen, have strong deleterious impacts on wheat and poplar wood production, respectively. Filamentous pathogens such as rust fungi secrete molecules called disease effectors that act as modulators of host cell physiology and can suppress or trigger host immunity. Current knowledge on effectors from other filamentous plant pathogens can be exploited for the characterisation of effectors in the genome of recently sequenced rust fungi. We designed a comprehensive in silico analysis pipeline to identify the putative effector repertoire from the genome of two plant pathogenic rust fungi. The pipeline is based on the observation that known effector proteins from filamentous pathogens have at least one of the following properties: (i contain a secretion signal, (ii are encoded by in planta induced genes, (iii have similarity to haustorial proteins, (iv are small and cysteine rich, (v contain a known effector motif or a nuclear localization signal, (vi are encoded by genes with long intergenic regions, (vii contain internal repeats, and (viii do not contain PFAM domains, except those associated with pathogenicity. We used Markov clustering and hierarchical clustering to classify protein families of rust pathogens and rank them according to their likelihood of being effectors. Using this approach, we identified eight families of candidate effectors that we consider of high value for functional characterization. This study revealed a diverse set of candidate effectors, including families of haustorial expressed secreted proteins and small cysteine-rich proteins. This comprehensive classification of candidate effectors from these devastating rust pathogens is an initial step towards probing plant germplasm for novel resistance components.

  4. Short communication: Emergence of a new race of leaf rust with combined virulence to Lr14a and Lr72 genes on durum wheat

    Energy Technology Data Exchange (ETDEWEB)

    Soleiman, N.H; Solis, I.; Soliman, M.H.; Sillero, J.C.; Villegas, D.; Alvaro, F.; Royo, C.; Serra, J.; Ammar, K.; Martínez-Moreno, F.

    2016-11-01

    Leaf rust is a foliar disease caused by the fungus Puccinia triticina that may severely reduce durum wheat yield. Resistance to this pathogen is common in modern durum germplasm but is frequently based on Lr72 and Lr14a. After accounts of races with virulence to Lr14a gene in France in 2000, the present study reports the detection in 2013 for the first time of a new race with virulence to Lr14a and Lr72. The aim of this work was to characterize the virulence pattern of four Spanish isolates with virulence to Lr14a, and to discuss the consequences of this presence. Rusted leaves from cultivars ‘Don Jaime’ (Lr14a) and ‘Gallareta’ (Lr72) were collected in 2013 in the field at two Spanish sites, one in the south (near Cadiz) and another in the north (near Girona). Spores from single pustule for each cultivar and site were multiplied on susceptible cultivar ‘Don Rafael’. Then, the four isolates were inoculated on a set of 19 isogenic lines Thatcher to characterize their virulence spectrum. All isolates presented the same virulence pattern. They were virulent on both Lr14a and Lr72 and the race was named DBB/BS. This race was very similar to those reported in 2009-11, but with added virulence to Lr14a. The resistance based on Lr14a has therefore been overcome in Spain, by a new race that has likely emerged via stepwise mutation from the local predominating races. This information is important to guide breeders in their breeding programmes and gene deployment strategies. (Author)

  5. Comparative genomics of Australian isolates of the wheat stem rust pathogen Puccinia graminis f. sp. tritici reveals extensive polymorphism in candidate effector genes

    Directory of Open Access Journals (Sweden)

    Narayana Mithur Upadhyaya

    2015-01-01

    Full Text Available The wheat stem rust fungus Puccinia graminis f. sp. tritici (Pgt, is one of the most destructive pathogens of wheat. In this study, a draft genome was built for a founder Australian Pgt isolate of pathotype (pt. 21-0 (collected in 1954 by next generation DNA sequencing. A combination of reference-based assembly using the genome of the previously sequenced American Pgt isolate CDL 75-36-700-3 (p7a and de novo assembly were performed resulting in a 92 Mbp reference genome for Pgt isolate 21-0. Approximately 13 Mbp of de novo assembled sequence in this genome is not present in the p7a reference assembly. This novel sequence is not specific to 21-0 as it is also present in three other Pgt rust isolates of independent origin.The new reference genome was subsequently used to build a pan-genome based on five Australian Pgt isolates. Transcriptomes from germinated urediniospores and haustoria were separately assembled for pt. 21-0 and comparison of gene expression profiles showed differential expression in ~10% of the genes each in germinated spores and haustoria. A total of 1,924 secreted proteins were predicted from the 21-0 transcriptome, of which 520 were classified as haustorial secreted proteins (HSPs. Comparison of 21-0 with two presumed clonal field derivatives of this lineage (collected in 1982 and 1984 that had evolved virulence on four additional resistance genes (Sr5, Sr11, Sr27, SrSatu identified mutations in 25 HSP effector candidates, some of which could explain their novel virulence phenotypes.

  6. Next generation sequencing provides rapid access to the genome of Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust.

    Directory of Open Access Journals (Sweden)

    Dario Cantu

    Full Text Available BACKGROUND: The wheat stripe rust fungus (Puccinia striiformis f. sp. tritici, PST is responsible for significant yield losses in wheat production worldwide. In spite of its economic importance, the PST genomic sequence is not currently available. Fortunately Next Generation Sequencing (NGS has radically improved sequencing speed and efficiency with a great reduction in costs compared to traditional sequencing technologies. We used Illumina sequencing to rapidly access the genomic sequence of the highly virulent PST race 130 (PST-130. METHODOLOGY/PRINCIPAL FINDINGS: We obtained nearly 80 million high quality paired-end reads (>50x coverage that were assembled into 29,178 contigs (64.8 Mb, which provide an estimated coverage of at least 88% of the PST genes and are available through GenBank. Extensive micro-synteny with the Puccinia graminis f. sp. tritici (PGTG genome and high sequence similarity with annotated PGTG genes support the quality of the PST-130 contigs. We characterized the transposable elements present in the PST-130 contigs and using an ab initio gene prediction program we identified and tentatively annotated 22,815 putative coding sequences. We provide examples on the use of comparative approaches to improve gene annotation for both PST and PGTG and to identify candidate effectors. Finally, the assembled contigs provided an inventory of PST repetitive elements, which were annotated and deposited in Repbase. CONCLUSIONS/SIGNIFICANCE: The assembly of the PST-130 genome and the predicted proteins provide useful resources to rapidly identify and clone PST genes and their regulatory regions. Although the automatic gene prediction has limitations, we show that a comparative genomics approach using multiple rust species can greatly improve the quality of gene annotation in these species. The PST-130 sequence will also be useful for comparative studies within PST as more races are sequenced. This study illustrates the power of NGS for

  7. Short communication: Emergence of a new race of leaf rust with combined virulence to Lr14a and Lr72 genes on durum wheat

    Directory of Open Access Journals (Sweden)

    Nour H. Soleiman

    2016-08-01

    Full Text Available Leaf rust is a foliar disease caused by the fungus Puccinia triticina that may severely reduce durum wheat yield. Resistance to this pathogen is common in modern durum germplasm but is frequently based on Lr72 and Lr14a. After accounts of races with virulence to Lr14a gene in France in 2000, the present study reports the detection in 2013 for the first time of a new race with virulence to Lr14a and Lr72. The aim of this work was to characterize the virulence pattern of four Spanish isolates with virulence to Lr14a, and to discuss the consequences of this presence. Rusted leaves from cultivars ‘Don Jaime’ (Lr14a and ‘Gallareta’ (Lr72 were collected in 2013 in the field at two Spanish sites, one in the south (near Cadiz and another in the north (near Girona. Spores from single pustule for each cultivar and site were multiplied on susceptible cultivar ‘Don Rafael’. Then, the four isolates were inoculated on a set of 19 isogenic lines Thatcher to characterize their virulence spectrum. All isolates presented the same virulence pattern. They were virulent on both Lr14a and Lr72 and the race was named DBB/BS. This race was very similar to those reported in 2009-11, but with added virulence to Lr14a. The resistance based on Lr14a has therefore been overcome in Spain, by a new race that has likely emerged via stepwise mutation from the local predominating races. This information is important to guide breeders in their breeding programmes and gene deployment strategies.

  8. Evidence for Increased Aggressiveness in a Recent Widespread Strain of Puccinia striiformis f. sp. tritici Causing Stripe Rust of Wheat

    DEFF Research Database (Denmark)

    Milus, Eugene A; Kristensen, Kristian; Hovmøller, Mogens S

    2009-01-01

    Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, has become more severe in eastern United States, Australia, and elsewhere since 2000. Recent research has shown that this coincided with a global spread of two closely related strains that were similar based...... regimes for latent period, lesion length, lesion width, lesion area, and spore production on adult plants of a susceptible wheat cultivar with no known genes for resistance to stripe rust. "New" isolates (since 2000) were significantly more aggressive than "old" isolates (before 2000) for all variables...... that wheat rust fungi can adapt to warmer temperatures and cause severe disease in previously unfavorable environments...

  9. Fungus-insect gall of Phlebopus portentosus.

    Science.gov (United States)

    Zhang, Chun-Xia; He, Ming-Xia; Cao, Yang; Liu, Jing; Gao, Feng; Wang, Wen-Bing; Ji, Kai-Ping; Shao, Shi-Cheng; Wang, Yun

    2015-01-01

    Phlebopus portentosus is a popular edible wild mushroom found in the tropical Yunnan, China, and northern Thailand. In its natural habitats, a gall often has been found on some plant roots, around which fungal fruiting bodies are produced. The galls are different from common insect galls in that their cavity walls are not made from plant tissue but rather from the hyphae of P. portentosus. Therefore we have termed this phenomenon "fungus-insect gall". Thus far six root mealy bug species in the family Pseudococcidae that form fungus-insect galls with P. portentosus have been identified: Formicococcus polysperes, Geococcus satellitum, Planococcus minor, Pseudococcus cryptus, Paraputo banzigeri and Rastrococcus invadens. Fungus-insect galls were found on the roots of more than 21 plant species, including Delonix regia, Citrus maxima, Coffea arabica and Artocarpus heterophyllus. Greenhouse inoculation trials showed that fungus-insect galls were found on the roots of A. heterophyllus 1 mo after inoculation. The galls were subglobose to globose, fulvous when young and became dark brown at maturation. Each gall harbored one or more mealy bugs and had a chimney-like vent for ventilation and access to the gall. The cavity wall had three layers. Various shaped mealy bug wax deposits were found inside the wall. Fungal hyphae invaded the epidermis of plant roots and sometimes even the cortical cells during the late stage of gall development. The identity of the fungus inside the cavity was confirmed by molecular methods. © 2015 by The Mycological Society of America.

  10. McGISH identification and phenotypic description of leaf rust and yellow rust resistant partial amphiploids originating from a wheat × Thinopyrum synthetic hybrid cross.

    Science.gov (United States)

    Kruppa, Klaudia; Türkösi, Edina; Mayer, Marianna; Tóth, Viola; Vida, Gyula; Szakács, Éva; Molnár-Láng, Márta

    2016-11-01

    A Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid wheatgrass is an excellent source of leaf and stem rust resistance produced by N.V.Tsitsin. Wheat line Mv9kr1 was crossed with this hybrid (Agropyron glael) in Hungary in order to transfer its advantageous agronomic traits into wheat. As the wheat parent was susceptible to leaf rust, the transfer of resistance was easily recognizable in the progenies. Three different partial amphiploid lines with leaf rust resistance were selected from the wheat/Thinopyrum hybrid derivatives by multicolour genomic in situ hybridization. Chromosome counting on the partial amphiploids revealed 58 chromosomes (18 wheatgrass) in line 194, 56 (14 wheatgrass) in line 195 and 54 (12 wheatgrass) in line 196. The wheat chromosomes present in these lines were identified and the wheatgrass chromosomes were characterized by fluorescence in situ hybridization using the repetitive DNA probes Afa-family, pSc119.2 and pTa71. The 3D wheat chromosome was missing from the lines. Molecular marker analysis showed the presence of the Lr24 leaf rust resistance gene in lines 195 and 196. The morphological traits were evaluated in the field during two consecutive seasons in two different locations.

  11. Effect of white pine blister rust (Cronartium ribicola) and rust-resistance breeding on genetic variation in western white pine Pinus monticola)

    Science.gov (United States)

    M. -S. Kim; S. J. Brunsfeld; G. I. McDonald; N. B. Klopfenstein

    2003-01-01

    Western white pine (Pinus monticola) is an economically and ecologically important species from western North America that has declined over the past several decades mainly due to the introduction of blister rust (Cronartium ribicola) and reduced opportunities for regeneration. Amplified fragment length polymorphism (AFLP) was used...

  12. Contamination of Pine Seeds by the Pitch Canker Fungus

    Science.gov (United States)

    L. David Dwinell; S.W. Fraedrich

    1999-01-01

    The pitch canker fungus, Fusarium subglutinans f. sp. pini, has been identified as a significant problem in man pine seed orchards and nursuries in the South. THe fungus causes strobilus mortality, seed deterioation, and cankers on the main stem, branches, and shoots of pines Dwinell and others 1985). The pitche canker fungus...

  13. Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

    DEFF Research Database (Denmark)

    Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R

    2009-01-01

    Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. We have analyzed one such system at the molecular level and found...

  14. Resistance in Salix against willow leaf rust caused by Melampsora epitea

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Leif [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Crop Production Science

    2000-07-01

    Cultivation of Salix in short rotation forests (SRF), as a source of renewable energy is a relatively recent phenomenon in Sweden. As all other crops under intensive cultivation, Salix are attacked by pests. The economically most important disease is leaf rust caused by Melampsora epitea. For successful plant breeding of new sustainable rust resistant clones, it is important to have knowledge of the inheritance of resistance and the mechanisms underlying rust resistance. Species hybridisation is one technique used in plant breeding, hence the inheritance pattern of rust resistance in hybrids of two species, S. viminalis and S. dasyclados, selected for the purpose, was studied in greenhouse as well as under field conditions. The study in greenhouse showed that hybrids acquire intermediate rust resistance compared to pure species. Plants of same hybrids in field proved to be more resistant than their parental species. Observations in field also showed that abiotic factors such as weather tend to play a significant role in expression of inheritance pattern. It was further indicated that the interaction between rust and Salix might be race-specific. Metabolic changes in Salix, induced by the pathogen in incompatible and compatible interactions were studied in terms of peroxidase and chitinase activity which were measured in S. viminalis inoculated with rust of two different pathotypes of M. epitea rust. Peroxidase activity revealed an earlier response from plants in the incompatible interactions compared to compatible interactions. Records of the chitinase accumulation showed absence of one basic isoform of chitinase in the incompatible interaction. These results demonstrated physiological differences between incompatible and compatible interactions, and gave further indication toward occurrence of race-specific interactions in this pathosystem. Further, with use of molecular biology techniques, a gene designated svpk1, was cloned and partially characterised. The gene

  15. Characterization and Mapping of Leaf Rust and Stripe Rust Resistance Loci in Hexaploid Wheat Lines UC1110 and PI610750 under Mexican Environments

    Directory of Open Access Journals (Sweden)

    Caixia Lan

    2017-08-01

    Full Text Available Growing resistant wheat varieties is a key method of minimizing the extent of yield losses caused by the globally important wheat leaf rust (LR and stripe rust (YR diseases. In this study, a population of 186 F8 recombinant inbred lines (RILs derived from a cross between a synthetic wheat derivative (PI610750 and an adapted common wheat line (cv. “UC1110” were phenotyped for LR and YR response at both seedling and adult plant stages over multiple seasons. Using a genetic linkage map consisting of single sequence repeats and diversity arrays technology markers, in combination with inclusive composite interval mapping analysis, we detected a new LR adult plant resistance (APR locus, QLr.cim-2DS, contributed by UC1110. One co-located resistance locus to both rusts, QLr.cim-3DC/QYr.cim-3DC, and the known seedling resistance gene Lr26 were also mapped. QLr.cim-2DS and QLr.cim-3DC showed a marginally significant interaction for LR resistance in the adult plant stage. In addition, two previously reported YR APR loci, QYr.ucw-3BS and Yr48, were found to exhibit stable performances in rust environments in both Mexico and the United States and showed a highly significant interaction in the field. Yr48 was also observed to confer intermediate seedling resistance against Mexican YR races, thus suggesting it should be re-classified as an all-stage resistance gene. We also identified 5 and 2 RILs that possessed all detected YR and LR resistance loci, respectively. With the closely linked molecular markers reported here, these RILs could be used as donors for multiple resistance loci to both rusts in wheat breeding programs.

  16. Genetic analysis of seedling resistance to crown rust in five diploid oat (Avena strigosa) accessions.

    Science.gov (United States)

    Cabral, A L; Park, R F

    2016-02-01

    Crown rust, caused by Puccinia coronata Corda f. sp. avenae Eriks., is a serious menace in oats, for which resistance is an effective means of control. Wild diploid oat accessions are a source of novel resistances that first need to be characterised prior to introgression into locally adapted oat cultivars. A genetic analysis of resistance to crown rust was carried out in three diverse diploid oat accessions (CIav6956, CIav9020, PI292226) and two cultivars (Saia and Glabrota) of A. strigosa. A single major gene conditioning resistance to Australian crown rust pathotype (Pt) 0000-2 was identified in each of the three accessions. Allelism tests suggested that these genes are either the same, allelic, or tightly linked with less than 1 % recombination. Similarly, a single gene was identified in Glabrota, and possibly two genes in Saia; both cultivars previously reported to carry two and three crown rust resistance genes, respectively. The identified seedling resistance genes could be deployed in combination with other resistance gene(s) to enhance durability of resistance to crown rust in hexaploid oat. Current diploid and hexaploid linkage maps and molecular anchor markers (simple sequence repeat [SSR] and diversity array technology [DArT] markers) should facilitate their mapping and introgression into hexaploid oat.

  17. Composition and structure of an iron-bearing, layered double hydroxide (LDH) - Green rust sodium sulphate

    DEFF Research Database (Denmark)

    Christiansen, B. C.; Balic-Zunic, T.; Petit, P. O.

    2009-01-01

    (III)(3)(SO4)(2)(OH)(18)center dot 12H(2)O, space group P-3, a = 9.528(6) angstrom, c = 10.968(8) angstrom and Z = 1. Green rust sodium sulphate, GR(Na,SO4) crystallizes in thin, hexagonal plates. Particles range from less than 50 nm to 2 mu m in diameter and are 40 nm thick or less. The material is redox......Mixed-valent Fe(II),Fe(III)-layered hydroxide, known as green rust, was synthesized from slightly basic, sodium sulphate solutions in an oxygen-free glove box. Solution conditions were monitored with pH and Eh electrodes and optimized to ensure a pure sulphate green-rust phase. The solid...... was characterised using Mossbauer spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the solution from which the green rust precipitated was established by mass and absorption spectroscopy. The sulphate form of green rust is composed of brucite-like layers...

  18. Resistance Potential of Bread Wheat Genotypes Against Yellow Rust Disease Under Egyptian Climate

    Directory of Open Access Journals (Sweden)

    Amer F. Mahmoud

    2015-12-01

    Full Text Available Yellow rust (stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive foliar diseases of wheat in Egypt and worldwide. In order to identify wheat genotypes resistant to yellow rust and develop molecular markers associated with the resistance, fifty F₈ recombinant inbred lines (RILs derived from a cross between resistant and susceptible bread wheat landraces were obtained. Artificial infection of Puccinia striiformis was performed under greenhouse conditions during two growing seasons and relative resistance index (RRI was calculated. Two Egyptian bread wheat cultivars i.e. Giza-168 (resistant and Sakha-69 (susceptible were also evaluated. RRI values of two-year trial showed that 10 RILs responded with RRI value >6 2 <6. However, only 7 RILs showed RRI value <2. Five RILs expressed hypersensitive type of resistance (R against the pathogen and showed the lowest Average Coefficient of Infection (ACI. Bulked segregant analysis (BSA with eight simple sequence repeat (SSR, eight sequence-related amplified polymorphism (SRAP and sixteen random amplified polymorphic DNA (RAPD markers revealed that three SSR, three SRAP and six RAPD markers were found to be associated with the resistance to yellow rust. However, further molecular analyses would be performed to confirm markers associated with the resistance and suitable for marker-assisted selection. Resistant RILs identified in the study could be efficiently used to improve the resistance to yellow rust in wheat.

  19. Genetics and mapping of stem rust resistance to Ug99 in the wheat cultivar Webster.

    Science.gov (United States)

    Hiebert, Colin W; Fetch, Thomas G; Zegeye, Taye

    2010-06-01

    New races of wheat stem rust, namely TTKSK (Ug99) and its variants, pose a threat to wheat production in the regions where they are found. The accession of the wheat cultivar Webster (RL6201) maintained at the Cereal Research Centre in Winnipeg, Canada, shows resistance to TTKSK and other races of stem rust. The purpose of this study was to study the inheritance of seedling resistance to stem rust in RL6201 and genetically map the resistance genes using microsatellite (SSR) markers. A population was produced by crossing the stem rust susceptible line RL6071 with Webster. The F(2) and F(3) were tested with TPMK, a stem rust race native to North America. The F(3) was also tested with TTKSK. Two independently assorting genes were identified in RL6201. Resistance to TPMK was conferred by Sr30, which was mapped with microsatellites on chromosome 5DL. The second gene, temporarily designated SrWeb, conferred resistance to TTKSK. SrWeb was mapped to chromosome 2BL using SSR markers. Comparison with previous genetic maps showed that SrWeb occupies a locus near Sr9. Further analysis will be required to determine if SrWeb is a new gene or an allele of a previously identified gene.

  20. Immobilization of chromate in hyperalkaline waste streams by green rusts and zero-valent iron.

    Science.gov (United States)

    Rogers, Christine M; Burke, Ian T; Ahmed, Imad A M; Shaw, Samuel

    2014-01-01

    Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COPR) leachate (pH approximately 12.2). Green rust removes chromate from high pH solutions (pH 10-12.5) very rapidly (<400 s). Chromate reduction rates for both green rust phases were consistently higher than for ZVI throughout the pH range studied; the surface area normalized rate constants were two orders of magnitude higher in the COPR leachate solution at pH 12.2. The performances of both green rusts were unaffected by changes in pH. In contrast, ZVI exhibited a marked decline in reduction rate with increasing pH to become almost ineffective above pH12.

  1. Entomology: A Bee Farming a Fungus.

    Science.gov (United States)

    Oldroyd, Benjamin P; Aanen, Duur K

    2015-11-16

    Farming is done not only by humans, but also by some ant, beetle and termite species. With the discovery of a stingless bee farming a fungus that provides benefits to its larvae, bees can be added to this list. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A endophytic fungus, Ramichloridium cerophilum, promotes growth ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-06-22

    Jun 22, 2016 ... Key words: Ramichloridium cerophilum, endophytic fungus, Chinese cabbage, plant growth promoting. INTRODUCTION. The mycorrhizal symbiosis between plants and fungi is common and most plant species are dependent on this symbiosis for improving the productivity and sustainability, including ...

  3. Rock phosphate solubilization by the ectomycorrhizal fungus ...

    African Journals Online (AJOL)

    SAM

    2014-06-18

    Jun 18, 2014 ... Despite this, a large proportion (75 to 90%) of fertilizer P .... nitrogen salts such as Urea, KNO3, NaNO3, NH4Cl, NaNO2 (Figure. 2). Phospholytic activity of fungus along with MHB strains without any carbon and nitrogen sources acted as control and .... complexity of CaP chemistry, release of microbial.

  4. A endophytic fungus, Ramichloridium cerophilum , promotes growth ...

    African Journals Online (AJOL)

    A fungal endophyte, Ramichloridium cerophilum, was identified as a Class 2 endophytes species obtained from the leaf of common sowthistle (Sonchus oleraceus L). This fungus was found to grow endophylically in the roots of Chinese cabbage seedlings. Light microscopy of cross-sections of colonized Chinese cabbage ...

  5. Death from Fungus in the Soil

    Centers for Disease Control (CDC) Podcasts

    2012-12-17

    Dr. Shira Shafir, Assistant Professor of Epidemiology at the UCLA Fielding School of Public Health, discusses her study about fungus found in soil.  Created: 12/17/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/18/2012.

  6. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    2006-12-20

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

  7. Rock phosphate solubilization by the ectomycorrhizal fungus ...

    African Journals Online (AJOL)

    In the present study, few mycorrhizal helper bacterial (MHB) strains such as Pseudomonas putida, Erwinia herbicola and Bacillus subtilis were isolated and identified from surface sterilized basidiomata and mycorrhizosphere of an ectomycorrhizal fungus Laccaria fraterna association with Eucalyptus globulus. To evaluate ...

  8. White pine blister rust in Korea, Japan and other Asian regions: comparisons and implications for North America

    Science.gov (United States)

    M.-S. Kim; N. B. Klopfenstein; Y. Ota; S. K. Lee; K.-S. Woo; S. Kaneko

    2010-01-01

    This article briefly reviews the history of white pine blister rust, attributed to Cronartium ribicola, and addresses current research and management issues in South Korea, Japan and other regions of eastern Asia (China, Russia and Himalaya). For each region, the distribution, damage, aecial hosts, telial hosts and management of C. ribicola and other blister rust fungi...

  9. Discovery of a novel stem rust resistance allele in durum wheat that exhibits differential reactions to Ug99 isolates

    Science.gov (United States)

    Wheat stem rust, caused by Puccinia graminis f. sp. tritici Erikss. & E. Henn, can incur yield losses on susceptible cultivars of durum wheat, Triticum turgidum ssp. durum (Desf.) Husnot. Though several durum cultivars possess the stem rust resistance gene Sr13, additional genes in durum wheat effec...

  10. White pine blister rust resistance of 12 western white pine families at three field sites in the Pacific Northwest

    Science.gov (United States)

    Richard A. Sniezko; Robert Danchok; Jim Hamlin; Angelia Kegley; Sally Long; James Mayo

    2012-01-01

    Western white pine (Pinus monticola Douglas ex D. Don) is highly susceptible to the non-native, invasive pathogen Cronartium ribicola, the causative agent of white pine blister rust. The susceptibility of western white pine to blister rust has limited its use in restoration and reforestation throughout much of western North...

  11. Targeted introgression of a wheat stem rust resistance gene by DNA marker-assisted chromosome engineering genetics

    Science.gov (United States)

    In wheat (Triticum aestivum L.), stem rust resistance gene Sr39, derived from Aegilops speltoides Tausch, is highly resistant to multiple stem rust races including TTKSK (Ug99). However, the gene has not been used in wheat breeding because of linkage drag associated with the large 2S chromosome segm...

  12. Screening for Sugarcane Brown Rust in the First Clonal Stage of the Canal Point Sugarcane Breeding Program

    Directory of Open Access Journals (Sweden)

    Duli Zhao

    2015-07-01

    Full Text Available Sugarcane (Saccharum spp. brown rust (caused by Puccinia melanocephala Syd. & P. Syd. was first reported in the United States in 1978 and is still one of the great challenges for sugarcane production. A better understanding of sugarcane genotypic variation in response to brown rust will help optimize breeding and selection strategies for disease resistance. Brown rust ratings were scaled from non-infection (0 to severe infection (4 with intervals of 0.5 and routinely recorded for genotypes in the first clonal selection stage of the Canal Point sugarcane breeding program in Florida. Data were collected from 14,272 and 12,661 genotypes and replicated check cultivars in 2012 and 2013, respectively. Mean rust rating, % infection, and severity in each family and progeny of female parent were determined, and their coefficients of variation (CV within and among families (females were estimated. Considerable variation exists in rust ratings among families or females. The families and female parents with high susceptibility or resistance to brown rust were identified and ranked. The findings of this study can help scientists to evaluate sugarcane crosses and parents for brown rust disease, to use desirable parents for crossing, and to improve genetic resistance to brown rust in breeding programs.

  13. QTL mapping provides evidence for lack of association of the avoidance of leaf rust in Hordeum chilense with stomata density

    NARCIS (Netherlands)

    Vaz Patto, M.C.; Rubiales, D.; Martin, A.; Hernandez, P.; Lindhout, W.H.; Niks, R.E.; Stam, P.

    2003-01-01

    In cereals, rust fungi are among the most harmful pathogens. Breeders usually rely on short-lived hypersensitivity resistance. As an alternative, "avoidance" may be a more durable defence mechanism to protect plants to rust fungi. In Hordeum chilense avoidance is based on extensive wax covering of

  14. Genetic mapping of stem rust resistance to Puccinia graminis f. sp. tritici race TRTTF in the Canadian wheat cultivar 'Harvest'

    Science.gov (United States)

    Stem rust, caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.(Pgt), is a destructive disease of wheat that can be controlled by deploying effective stem rust resistance (Sr) genes. Highly virulent races of Pgt in Africa have been detected and characterized. These include race T...

  15. Distribution and frequency of Bru1, a major brown rust resistance gene, in the sugarcane world collection

    Science.gov (United States)

    Brown rust, caused by Puccinia melanocephala, is an important disease of sugarcane worldwide. Molecular markers for a major brown rust resistance gene, Bru1, were used to screen a total of 1,282 clones in the World Collection of Sugarcane and Related Grasses (WCSRG) to determine the distribution and...

  16. Identification of nine pathotype-specific genes conferring resistance to fusiform rust in loblolly pine (Pinus taeda L.)

    Science.gov (United States)

    Henry Amerson; C. Dana Nelson; Thomas L. Kubisiak; E.George Kuhlman; Saul Garcia

    2015-01-01

    Nearly two decades of research on the host-pathogen interaction in fusiform rust of loblolly pine is detailed. Results clearly indicate that pathotype-specific genes in the host interacting with pathogen avirulence cause resistance as defined by the non-gall phenotype under favorable environmental conditions for disease development. In particular, nine fusiform rust...

  17. Nitrate reduction by green rusts modified with trace metals.

    Science.gov (United States)

    Choi, Jeongyun; Batchelor, Bill; Won, Chanhee; Chung, Jinwook

    2012-02-01

    A kinetic study of nitrate reduction by green rust (GR), a group of layered Fe(II)-Fe(III) hydroxide solids, was performed using a batch reactor system. The reduction rate of nitrate by GRs was affected by the anion content in the interlayer of GRs. GR containing F(-) (GR-F) showed the fastest reduction rate while GR-SO(4) showed 9 times slower reaction rate than GR-F. The addition of 1mM Pt or Cu to GR that contained 85 mM Fe(II) improved the reduction kinetics of nitrate by up to 200 times. Pt was an effective activating agent for all GRs. The sequential step reaction model that we proposed appropriately simulated the experimental data. The fastest nitrate reduction by GR-F with Pt was achieved at pH 9 among 7.5 to 11. At that condition, 1mM nitrate transformed completely into ammonium within 23 min. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Efficacy of plant extracts in controlling wheat leaf rust disease caused by Puccinia triticina

    Directory of Open Access Journals (Sweden)

    Yasser M. Shabana

    2017-03-01

    Full Text Available The efficacy of eight plant extracts (garlic, clove, garden quinine, Brazilian pepper, anthi mandhaari, black cumin, white cedar and neem in controlling leaf rust disease of wheat was investigated in vitro and in vivo. In vitro, all treatments inhibited spore germination by more than 93%. Neem extract recorded 98.99% inhibition of spore germination with no significant difference from the fungicide Sumi-8 (100%. Under greenhouse conditions, seed soaking application in neem extract (at concentration of 2 ml/L resulted in 36.82% reduction in the number of pustules/leaf compared with the untreated control. Foliar spraying of plant extracts on wheat seedlings decreased the number of pustules/leaf. Foliar spraying of plant extracts four days after inoculation led to the highest resistance response of wheat plants against leaf rust pathogen. Spray application of wheat seedlings with neem, clove and garden quinine extracts, four days after inoculation with leaf rust pathogen completely prevented rust development (100% disease control and was comparable with the fungicide Sumi-8. Foliar spray application of wheat plants at mature stage with all plant extracts has significantly reduced the leaf rust infection (average coefficient of infection, ACI compared with the untreated control and neem was the most effective treatment. This was reflected on grain yield components, whereas the 1000-kernel weight and the test weight were improved whether under one- or two-spray applications, with two-spray application being more effective in this regard. Thus, it could be concluded that plant extracts may be useful to control leaf rust disease in Egypt as a safe alternative option to chemical fungicides.

  19. Cultivar mixtures for the simultaneous management of multiple diseases: tan spot and leaf rust of wheat.

    Science.gov (United States)

    Cox, C M; Garrett, K A; Bowden, R L; Fritz, A K; Dendy, S P; Heer, W F

    2004-09-01

    ABSTRACT Because of differences in life histories between Puccinia triticina, a highly specialized, polycyclic, windborne pathogen with a shallow dispersal gradient, and Pyrenophora tritici-repentis, a residue-borne pathogen with a steep dispersal gradient, wheat mixtures are expected to be more effective at controlling leaf rust than tan spot. The objectives of this research were to determine the effect of two-cultivar mixtures with varying proportions and different pathogen resistance profiles on the severity of tan spot and leaf rust, to evaluate yield of the mixtures in the presence or absence of disease, and to directly compare the relative effectiveness of cultivar mixing for tan spot versus leaf rust. In a field experiment at two sites in Kansas over two growing seasons, winter wheat cvs. Jagger and 2145, which have differential resistance reactions to leaf rust and tan spot, each were planted in proportions of 0.25, 0.50, 0.75, and 1.00. Plots were inoculated with each pathogen alone, both pathogens, treated with a fungicide, or exposed to ambient conditions. For both diseases for all siteyears, severity decreased substantially on the susceptible cultivar as the proportion of that cultivar decreased in mixture. Mixtures were significantly more effective at reducing leaf rust than tan spot in three of four site-years. Mixtures generally yielded the same as the weighted mean of components in monoculture although, in two of three site-years, at least one fungicide-treated and one diseased mixture each yielded higher than expected values. Although this particular mixture produced only modest yield benefits, the potential for simultaneous reductions in tan spot and leaf rust was demonstrated.

  20. Genome-Wide Association Mapping of Stem Rust Resistance in Hordeum vulgare subsp. spontaneum

    Directory of Open Access Journals (Sweden)

    Ahmad H. Sallam

    2017-10-01

    Full Text Available Stem rust was one of the most devastating diseases of barley in North America. Through the deployment of cultivars with the resistance gene Rpg1, losses to stem rust have been minimal over the past 70 yr. However, there exist both domestic (QCCJB and foreign (TTKSK aka isolate Ug99 pathotypes with virulence for this important gene. To identify new sources of stem rust resistance for barley, we evaluated the Wild Barley Diversity Collection (WBDC (314 ecogeographically diverse accessions of Hordeum vulgare subsp. spontaneum for seedling resistance to four pathotypes (TTKSK, QCCJB, MCCFC, and HKHJC of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici, Pgt and one isolate (92-MN-90 of the rye stem rust pathogen (P. graminis f. sp. secalis, Pgs. Based on a coefficient of infection, the frequency of resistance in the WBDC was low ranging from 0.6% with HKHJC to 19.4% with 92-MN-90. None of the accessions was resistant to all five cultures of P. graminis. A genome-wide association study (GWAS was conducted to map stem rust resistance loci using 50,842 single-nucleotide polymorphic markers generated by genotype-by-sequencing and ordered using the new barley reference genome assembly. After proper accounting for genetic relatedness and structure among accessions, 45 quantitative trait loci were identified for resistance to P. graminis across all seven barley chromosomes. Three novel loci associated with resistance to TTKSK, QCCJB, MCCFC, and 92-MN-90 were identified on chromosomes 5H and 7H, and two novel loci associated with resistance to HKHJC were identified on chromosomes 1H and 3H. These novel alleles will enhance the diversity of resistance available for cultivated barley.

  1. Melampsora rust species on biomass willows in central and north-eastern Germany.

    Science.gov (United States)

    Bubner, Ben; Wunder, Sebastian; Zaspel, Irmtraut; Zander, Matthias; Gloger, Jan; Fehrenz, Steffen; Ulrichs, Christian

    2014-11-01

    Melampsora willow rusts are the most important fungal pathogens in short rotation coppices of biomass willows. In the past, breeding programmes for rust resistant biomass willows concentrated on the distinction of races within the forma specialis Melampsora larici-epitea f. sp. larici-epitea typica that colonized Salix viminalis and related clones. In a new breeding program that is based on a wider range of willow species it is necessary to identify further Melampsora species and formae specialis that are pathogens of willow species other than S. viminalis. Therefore, three stock collections with Salix daphnoides, Salix purpurea, and other shrub willow species (including S. viminalis) species were sampled in north-eastern Germany. A fourth stock collection in central Germany contributed rusts of tree willows (Salix fragilis and Salix alba) and the large shrub Salix caprea. Out of 156 rust samples, 149 were successfully sequenced for ITS rDNA. A phylogenetic analysis combining Neighbour-Joining, Maximum-Likelihood and Bayesian analysis revealed six species: Melampsora ribesii-purpureae, Melampsora allii-salicis-albae, Melampsora sp. aff. allii-fragilis, Melampsora larici-pentandrae, Melampsora larici-caprearum, and Melampsora larici-epitea. The first four species were found exclusively on the expected hosts. Melampsora larici-caprearum had a wider host range comprising S. caprea and S. viminalis hybrids. Melampsora larici-epitea can be further differentiated into two formae speciales. The forma specialis larici-epitea typica (59 samples) colonized Salix viminalis clones, Salix purpurea, Salix×dasyclados, and Salix×aquatica. In contrast to this relatively broad host range, f. sp. larici-daphnoides (65 samples) was found exclusively on Salix daphnoides. With the distinction and identification of the rust species/formae speciales it is now possible to test for race-specific resistances in a more targeted manner within the determined pairings of rust and willow

  2. Potential impact of climate change on coffee rust over Mexico and Central America

    Science.gov (United States)

    Calderon-Ezquerro, Maria del Carmen; Martinez-Lopez, Benjamin; Cabos Narvaez, William David; Sein, Dmitry

    2017-04-01

    In this work, some meteorological variables from a regional climate model are used to characterize the dispersion of coffee rust (a fungal disease) from Central America to Mexico, during the 20 Century. The climate model consists of the regional atmosphere model REMO coupled to the MPIOM global ocean model with increased resolution in the Atlantic Ocean. Lateral atmospheric and upper oceanic boundary conditions outside the coupled domain were prescribed using both ERA-40 and ERA-Interim reanalysis data. In addition to the historical simulation, a projection of the evolution of the coffee rust for the 21 Century was obtained from a REMO run using MPIESM data for the lateral forcing.

  3. La Roya naranja de la caña de azúcar, una enfermedad emergente: su impacto y comparación con la roya marrón English Translation: Orange rust of sugarcane, an emerging disease: its impact and comparison to brown rust.

    Science.gov (United States)

    Sugarcane orange rust, caused by Puccinia kuehnii, was first detected in Florida in 2007, the first for Western Hemisphere. Subsequently, it has spread to the majority of sugarcane producing countries in the hemisphere. Orange rust is distinguished from brown rust its pustule size which is slightl...

  4. Antimicrobial constituents from endophytic fungus Fusarium sp.

    Directory of Open Access Journals (Sweden)

    Hidayat Hussain

    2015-03-01

    Full Text Available Objective: To evaluate the antimicrobial potential of fraction of the fungus Fusarium sp. and study the tentative identification of their active constituents. Methods: Six compounds were purified from an fraction of endophytic fungus Fusarium sp. using column chromatography and their structures have been confirmed based on 1H and 13C nuclear magnetic resonance spectra, distortionless enhancement by polarization transfer, 2D COSY, heteronuclear multiple quantum correlation and heteronuclear multiple bond correlation experiments. The six isolated compounds were screened for antimicrobial activity using the agar well diffusion method. Results: Phytochemical investigation of endophytic fungus Fusarium sp. lead to the isolation and identification of the following compounds viz., colletorin B, colletochlorin B, LL-Z1272β (llicicolin B, 4,5-dihydroascochlorin, ascochlorin, and 4,5-dihydrodechloroascochlorin. Colletorin B and colletochlorin B displayed moderate herbicidal, antifungal and antibacterial activities towards Chlorella fusca, Ustilago violacea, Fusarium oxysporum, and Bacillus megaterium. On the other hand LL-Z1272β (llicicolin B showed moderate antifungal activity towards Ustilago violacea and Fusarium oxysporum while 4,5-dihydroascochlorin showed strong antibacterial activity towards Bacillus megaterium. Furthermore, 4,5-dihydrodechloroascochlorin showed very strong antifungal activity towards Eurotium repens. Conclusions: Antimicrobial activities demonstrated by five of the six isolated compounds clearly demonstrate that these fungi extracts and active compounds present a great potential for the food, cosmetic and pharmaceutical industries.

  5. Adult plant leaf rust resistance derived from Toropi wheat is conditioned by Lr78 and three minor QTL.

    Science.gov (United States)

    Kolmer, James; Bernardo, Amy; Bai, Guihua; Hayden, Matt; Chao, Shiaoman

    2017-10-09

    Leaf rust caused by Puccinia triticina is an important disease of wheat in many regions worldwide. Durable or long lasting leaf rust resistance has been difficult to achieve because populations of P. triticina are highly variable for virulence to race-specific resistance genes, and respond to selection by resistance genes in released wheat cultivars. The wheat cultivar Toropi, developed and grown in Brazil, was noted to have long lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat background. In the first population, a single gene with major effects on chromosome 5DS that mapped 2.2 cM distal to IWA6289, strongly reduced leaf rust severity in all three years of field plot tests. This gene for adult plant leaf rust resistance was designated as Lr78. In the second population, QTL with small effects on chromosomes 1BL, 3BS, and 4BS were found. These QTL expressed inconsistently over four years of field plot tests. The adult plant leaf rust resistance derived from Toropi involved a complex combination of QTL with large and small effects.

  6. Using Landscape Genetics Simulations for Planting Blister Rust Resistant Whitebark Pine in the US Northern Rocky Mountains

    Science.gov (United States)

    Landguth, Erin L.; Holden, Zachary A.; Mahalovich, Mary F.; Cushman, Samuel A.

    2017-01-01

    Recent population declines to the high elevation western North America foundation species whitebark pine, have been driven by the synergistic effects of the invasive blister rust pathogen, mountain pine beetle (MPB), fire exclusion, and climate change. This has led to consideration for listing whitebark pine (WBP) as a threatened or endangered species under the Endangered Species Act, which has intensified interest in developing management strategies for maintaining and restoring the species. An important, but poorly studied, aspect of WBP restoration is the spatial variation in adaptive genetic variation and the potential of blister rust resistant strains to maintain viable populations in the future. Here, we present a simulation modeling framework to improve understanding of the long-term genetic consequences of the blister rust pathogen, the evolution of rust resistance, and scenarios of planting rust resistant genotypes of whitebark pine. We combine climate niche modeling and eco-evolutionary landscape genetics modeling to evaluate the effects of different scenarios of planting rust-resistant genotypes and impacts of wind field direction on patterns of gene flow. Planting scenarios showed different levels for local extirpation of WBP and increased population-wide blister rust resistance, suggesting that the spatial arrangement and choice of planting locations can greatly affect survival rates of whitebark pine. This study presents a preliminary, but potentially important, framework for facilitating the conservation of whitebark pine. PMID:28239390

  7. Genome-Wide Association Mapping Reveals Novel QTL for Seedling Leaf Rust Resistance in a Worldwide Collection of Winter Wheat

    Directory of Open Access Journals (Sweden)

    Genqiao Li

    2016-11-01

    Full Text Available Leaf rust of wheat ( L. is a major disease that causes significant yield losses worldwide. The short-lived nature of leaf rust resistance ( genes necessitates a continuous search for novel sources of resistance. We performed a genome-wide association study (GWAS on a panel of 1596 wheat accessions. The panel was evaluated for leaf rust reaction by testing with a bulk of Eriks. ( isolates collected from multiple fields of Oklahoma in 2013 and two predominant races in the fields of Oklahoma in 2015. The panel was genotyped with a set of 5011 single-nucleotide polymorphism (SNP markers. A total of 14 quantitative trait loci (QTL for leaf rust resistance were identified at a false discovery rate (FDR of 0.01 using the mixed linear model (MLM. Of these, eight QTL reside in the vicinity of known genes or QTL, and more studies are needed to determine their relationship with known loci. is a new QTL to bread wheat but is close to a locus previously identified in durum wheat [ L. subsp. (Desf. Husn.]. The other five QTL, including , , , , and , are likely novel loci for leaf rust resistance. The uneven distribution of the 14 QTL in the six subpopulations of the panel suggests that wheat breeders can enhance leaf rust resistance by selectively introgressing some of these QTL into their breeding materials. In addition, another 31 QTL were significantly associated with leaf rust resistance at a FDR of 0.05.

  8. The influence of canopy density on willow leaf rust (Melampsora epitea) severity in willow short rotation coppice

    Energy Technology Data Exchange (ETDEWEB)

    Toome, M.; Heinsoo, K.; Holm, B.; Luik, A. [Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1A, Tartu 51014 (Estonia)

    2010-08-15

    Willow short rotation coppice is used as a renewable energy source and also as a vegetation filter for purifying wastewater. Wastewater irrigation might change microclimatic conditions and increase the canopy density in plantations, which might decrease production due to leaf rust (Melampsora epitea). The aim of this study was to estimate the impact of the canopy density on rust abundance on willows. For that, we counted rust pustules on leaves of five different willow clones from dense and sparse areas in both the wastewater irrigated and control part of the plantation. The results demonstrated clear differences between clones; clone '81090' was very susceptible, '78183' susceptible, '78021' fairly tolerant and 'Tora' rust resistant. Clone 'Gudrun', which was previously reported resistant, had severe rust damages in Estonia. In the case of clones '78183' and '78021' there were significantly more rust pustules per leaf unit area at areas with denser canopy, which confirmed that higher plant density could result in biomass losses caused by leaf rust. No differences, however, were detected between dense and sparse areas of hybrid clone 'Gudrun', most probably because in this particular case leaves from upper canopy layer were used. There was a tendency detected that clones with a higher number of shoots per plant had more rust damages on their leaves, however, the correlation was not statistically confirmed. In conclusion, the impact of canopy density on rust abundance is clone-specific and significant in the case of clones on which infection starts from the lower part of the canopy. (author)

  9. Control of Asian soybean rust with mancozeb, a multi-site fungicide

    Directory of Open Access Journals (Sweden)

    Luís Henrique Carregal Pereira da Silva

    2015-03-01

    Full Text Available An experiment conducted in the field the action of mancozeb, a fungicide of multi-site action was tested, to control soybean rust caused by Phakopsora pachyrhizi. Its performance was compared to that of the mixture cyproconazole (DMI + azoxystrobin (QoI. The soybean cultivar NA 7337 RR was used with a population of 400,000 plants/ha cultivated in 20m2 plots. Treatments consisted of mancozeb levels (1.5 and 2.0 kg/ha applied four, six and eight times. The DMI + QoI mixture was applied three times at 0.3 L/ha + Nimbus. Rust severity was assessed six times in the plots and data were integrated as the area under the disease progress curve (AUDPC. The plots were harvested and grain yield was expressed as kg/ha. Data on AUDPC and yield were subjected to analysis of variance and means compared according to Turkey's test (p = 0.005. Treatments with mancozeb were superior to DMI + QoI mixture both for rust control and grain yield. Four applications of 2.0 k/ha mancozeb were more efficient than three applications of the mixture used as standard. Mancozeb has the potential to be added to fungicide mixtures in the establishment of soybean rust anti-resistance strategy.

  10. Cultured cells of white pine show genetic resistance to axenic blister rust hyphae.

    Science.gov (United States)

    Diner, A M; Mott, R L; Amerson, H V

    1984-04-27

    Hypersensitive resistance to axenically cultured Cronartium ribicola was displayed by subcultured callus of Pinus lambertiana. Cellular resistance to a destructive rust disease can now be studied at the macromolecular level through use of cloned cells of both host and pathogen in a system amenable to emerging recombinant DNA technology.

  11. Genetics of adult plant stripe rust resistance in CSP44, a selection ...

    Indian Academy of Sciences (India)

    Unknown

    areas of temperate zones (Johnson 1988). Yield losses can be considerable, ranging from about 40 per cent to com- plete destruction of the crop depending upon the growth stage at which the disease attacks. Using diverse genes for resistance against stripe rust disease is the most eco- nomical and environmentally safe ...

  12. Mapping fusiform rust resistance genes within a complex mating design of loblolly pine

    Science.gov (United States)

    Tania Quesada; Marcio F.R. Resende Jr.; Patricio Munoz; Jill L. Wegrzyn; David B. Neale; Matias Kirst; Gary F. Peter; Salvador A. Gezan; C.Dana Nelson; John M. Davis

    2014-01-01

    Fusiform rust resistance can involve gene-for-gene interactions where resistance (Fr) genes in the host interact with corresponding avirulence genes in the pathogen, Cronartium quercuum f.sp. fusiforme (Cqf). Here, we identify trees with Fr genes in a loblolly pine population derived from a complex mating design challenged with two Cqf inocula (one gall and 10 gall...

  13. Polymerase Chain Reaction (PCR) applications in white pine blister rust resistance screening

    Science.gov (United States)

    Sam Hendricks; Wendy Sutton; Jeffrey Stone; Richard Sniezko; Angelia Kegley; Anna Schoettle

    2011-01-01

    A goal of breeding programs for resistance to white pine blister rust is the development of multigenic resistance, even if the genetics and mechanisms of resistance may be imperfectly understood. The goal of multigenic resistance has prompted efforts to categorize host resistance reactions at increasingly finer scales, to identify heritable traits that may confer...

  14. First Report of Orange Rust of Sugarcane caused by Puccinia kuehnii in Ecuador

    Science.gov (United States)

    Orange rust, Puccinia kuehnii (W. Krüger) E.J. Butler, is an important disease of sugarcane (complex hybrid of Saccharum L. species) that causes yield losses, and impacts breeding programs. Initially confined to the Asia-Oceania region (5), P. kuehnii was reported in Florida in June 2007 (2) and lat...

  15. Genetics of leaf and stripe rust resistance in a bread wheat cultivar ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 87; Issue 2. Genetics of leaf and stripe rust resistance in a bread wheat cultivar Tonichi. Satinder Kaur U. K. Bansal Renu Khanna R. G. Saini. Research Note Volume 87 Issue 2 August 2008 pp 191-194 ...

  16. Image processing methods for quantitatively detecting soybean rust from multispectral images

    Science.gov (United States)

    Soybean rust, caused by Phakopsora pachyrhizi, is one of the most destructive diseases for soybean production. It often causes significant yield loss and may rapidly spread from field to field through airborne urediniospores. In order to implement timely fungicide treatments for the most effective c...

  17. Identification of leaf rust resistant gene Lr10 in Pakistani wheat ...

    African Journals Online (AJOL)

    Jane

    2011-08-10

    Aug 10, 2011 ... been reported in many wheat producing countries in most years and periodic epidemics during the last century resulted in famine situation in many parts of the world. Allan et al. (1963) and Ali et al. (2007) have also reported the existence of association between rust infection and grain yield losses. To date ...

  18. Research on the biology of fusiform rust in the southeastern United States

    Science.gov (United States)

    Pauline. Spaine

    1998-01-01

    The incidence of fusiform rust has continued to be one of the major forest disease problems in the Southeastern United States. In the past, much of the research has concentrated on field studies with provenance selection and genetic breeding of pine families to increase resistance in the host. In the last 10 years, there has been an increased interest in the actual...

  19. Flavonoid Accumulation Plays an Important Role in the Rust Resistance of Malus Plant Leaves

    Directory of Open Access Journals (Sweden)

    Yanfen Lu

    2017-07-01

    Full Text Available Cedar-apple rust (Gymnosporangium yamadai Miyabe is a fungal disease that causes substantial injury to apple trees and results in fruit with reduced size and quality and a lower commercial value. The molecular mechanisms underlying the primary and secondary metabolic effects of rust spots on the leaves of Malus apple cultivars are poorly understood. Using HPLC, we found that the contents of flavonoid compounds, especially anthocyanin and catechin, were significantly increased in rust-infected symptomatic tissue (RIT. The expression levels of structural genes and MYB transcription factors related to flavonoid biosynthesis were one- to seven-fold higher in the RIT. Among these genes, CHS, DFR, ANS, FLS and MYB10 showed more than a 10-fold increase, suggesting that these genes were expressed at significantly higher levels in the RIT. Hormone concentration assays showed that the levels of abscisic acid (ABA, ethylene (ETH, jasmonate (JA and salicylic acid (SA were higher in the RIT and were consistent with the expression levels of McNCED, McACS, McLOX and McNPR1, respectively. Our study explored the complicated crosstalk of the signal transduction pathways of ABA, ETH, JA and SA; the primary metabolism of glucose, sucrose, fructose and sorbitol; and the secondary metabolism of flavonoids involved in the rust resistance of Malus crabapple leaves.

  20. Flavonoid Accumulation Plays an Important Role in the Rust Resistance of Malus Plant Leaves.

    Science.gov (United States)

    Lu, Yanfen; Chen, Qi; Bu, Yufen; Luo, Rui; Hao, Suxiao; Zhang, Jie; Tian, Ji; Yao, Yuncong

    2017-01-01

    Cedar-apple rust (Gymnosporangium yamadai Miyabe) is a fungal disease that causes substantial injury to apple trees and results in fruit with reduced size and quality and a lower commercial value. The molecular mechanisms underlying the primary and secondary metabolic effects of rust spots on the leaves of Malus apple cultivars are poorly understood. Using HPLC, we found that the contents of flavonoid compounds, especially anthocyanin and catechin, were significantly increased in rust-infected symptomatic tissue (RIT). The expression levels of structural genes and MYB transcription factors related to flavonoid biosynthesis were one- to seven-fold higher in the RIT. Among these genes, CHS, DFR, ANS, FLS and MYB10 showed more than a 10-fold increase, suggesting that these genes were expressed at significantly higher levels in the RIT. Hormone concentration assays showed that the levels of abscisic acid (ABA), ethylene (ETH), jasmonate (JA) and salicylic acid (SA) were higher in the RIT and were consistent with the expression levels of McNCED, McACS, McLOX and McNPR1, respectively. Our study explored the complicated crosstalk of the signal transduction pathways of ABA, ETH, JA and SA; the primary metabolism of glucose, sucrose, fructose and sorbitol; and the secondary metabolism of flavonoids involved in the rust resistance of Malus crabapple leaves.

  1. Genetic variation in susceptibility to fusiform rust in seedlings from a wild population of loblolly pine

    Science.gov (United States)

    Bohun B. Kinloch Jr.; Roy W. Stonecypher

    1969-01-01

    Striking genetic variation in susceptibility to fusiform rust was observed among SS controlled-pollinated (CP) and 48 wind-pollinated (WP) families from parent trees of loblolly pine selected at random in a natural forest stand in southwest Georgia. The mating design permitted statistical tests for estimating both additive and total genetic variance. WP families were...

  2. Strong partial resistance to white pine blister rust in sugar pine

    Science.gov (United States)

    Bohun B. Kinloch, Jr.; Deems Burton; Dean A. Davis; Robert D. Westfall; Joan Dunlap; Detlev Vogler

    2012-01-01

    Quantitative resistance to white pine blister rust in 128 controlled- and open-pollinated sugar pine families was evaluated in a “disease garden”, where alternate host Ribes bushes were interplanted among test progenies. Overall infection was severe (88%), but with great variation among and within families: a 30-fold range in numbers of infections...

  3. Unravelling and managing fusiform rust disease: a model approach for coevolved forest tree pathosystems.

    Science.gov (United States)

    CD Nelson; TL Kubisiak; HV Amerson

    2010-01-01

    Fusiform rust disease remains the most destructive disease in pine plantations in the southern United States. Our ongoing research is designed to identify, map, and clone the interacting genes of the host and pathogen. Several resistance (R) genes have been identified and genetically mapped using informative pine families and single-spore isolate inoculations. In...

  4. Heterogeneous nonmarket benefits of managing white pine bluster rust in high-elevation pine forests

    Science.gov (United States)

    James R. Meldrum; Patricia A. Champ; Craig A. Bond

    2013-01-01

    This article describes a nonmarket valuation study about benefits of managing the invasive disease white pine blister rust in highelevation forests in the Western United States. Results demonstrate that, on average, households in the Western United States are willing to pay $154 to improve the resiliency of these forests. Factor analysis shows that long-run protection...

  5. Civic Capacity in Educational Reform Efforts: Emerging and Established Regimes in Rust Belt Cities

    Science.gov (United States)

    Mitra, Dana L.; Frick, William C.

    2011-01-01

    Using urban regime theory, the article examines two Rust Belt cities that tried to break the cycle of social reproduction in their communities by reforming their schools. The article contributes to the development of urban regime theory by comparing an "emerging" regime to an "established" regime. The comparison highlights the interdependent…

  6. Control of Fusiform Rust in Slash Pine with Bayleton (Triadimefon) Seed Treatment

    Science.gov (United States)

    Robert C. Hare; Glenn A. Snow

    1983-01-01

    The Bayleton® seed treatment protects pine seedlings against fusiform rust for at least 4 weeks after sowing. If nurserymen use treated seed, no more than three foliar sprays are needed during the season. These can be timed to give maximum protection during the most hazardous period and adequate protection for the remainder of the infection season.

  7. Selection of loblolly pine varieties resistant to fusiform rust for commercial deployment

    Science.gov (United States)

    Andy Benowicz; Robert J. Weir

    2012-01-01

    Benowicz, Andy; Weir, Robert J. 2013. Selection of loblolly pine varieties resistant to fusiform rust for commercial deployment . In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech. coords. Proceedings of the fourth international workshop on the genetics of host-parasite interactions in...

  8. Host range of Phakopsora pachyrhizi, the causal agent of soybean rust

    Science.gov (United States)

    Phakopsora pachyrhizi, the causal organism of soybean rust, was first described in 1903 from leaves of Glycine max subsp. soja, or wild soybean, in Japan. Since that time, there have been numerous reports of the pathogen on various leguminous species around the world, first in Asia, followed by Aust...

  9. Options for the management of white pine blister rust in the Rocky Mountain Region

    Science.gov (United States)

    Kelly S. Burns; Anna W. Schoettle; William R. Jacobi; Mary F. Mahalovich

    2008-01-01

    This publication synthesizes current information on the biology, distribution, and management of white pine blister rust (WPBR) in the Rocky Mountain Region. In this Region, WPBR occurs within the range of Rocky Mountain bristlecone pine (Pinus aristata), limber pine (P. flexilis), and whitebark pine (P. albicaulis...

  10. Monitoring white pine blister rust infection and mortality in whitebark pine in the Greater Yellowstone ecosystem

    Science.gov (United States)

    Cathie Jean; Erin Shanahan; Rob Daley; Gregg DeNitto; Dan Reinhart; Chuck Schwartz

    2011-01-01

    There is a critical need for information on the status and trend of whitebark pine (Pinus albicaulis) in the Greater Yellowstone Ecosystem (GYE). Concerns over the combined effects of white pine blister rust (WPBR, Cronartium ribicola), mountain pine beetle (MPB, Dendroctonus ponderosae), and climate change prompted an interagency working group to design and implement...

  11. Yellow Rust Epidemics Worldwide Were Caused by Pathogen Races from Divergent Genetic Lineages

    DEFF Research Database (Denmark)

    Ali, Sajid; Rodriguez Algaba, Julian; Thach, Tine

    2017-01-01

    We investigated whether the recent worldwide epidemics of wheat yellow rust were driven by races of few clonal lineage(s) or populations of divergent races. Race phenotyping of 887 genetically diverse Puccinia striiformis isolates sampled in 35 countries during 2009–2015 revealed...

  12. Virulence of wheat yellow rust races and resistance genes of wheat cultivars in Ecuador

    NARCIS (Netherlands)

    Ochoa, J.B.; Danial, D.L.; Paucar, B.

    2007-01-01

    Virulence factors of the yellow rust, Puccinia striiformis, populations in bread wheat were studied in Ecuador between 1973 and 2004. The number of virulence factors has increased markedly from very few in the early seventies to 16 at the end of the 90s. Isolates belonging to race 0E0 seem to be the

  13. Genetics and mapping of a new leaf rust resistance gene in Triticum ...

    Indian Academy of Sciences (India)

    AMIT KUMAR SINGH

    Abstract. A Triticum timopheevii-derived bread wheat line, Selection G12, was screened with 40 pathotypes of leaf rust pathogen,. Puccinia triticina at seedling stage and with two most commonly prevalent pathotypes 77-5 and 104-2 at adult plant stage. Selection G12 showed resistance at both seedling and adult plant ...

  14. Studies of the genetics of inheritance of stem rust resistance in ...

    African Journals Online (AJOL)

    Pgt race TTKSK (Ug99) has a wide virulence range with respect to currently grown wheat cultivars worldwide. Aspects of migration, mutation, recombination and selection in the pathogen have led to previously deployed stem rust resistance genes being ineffective. Race TTKSK has further evolved to acquire virulence for ...

  15. Identifying leaf rust resistance gene Lr19 in durum wheat using ...

    African Journals Online (AJOL)

    Leaf rust, caused by Puccinia triticina Eriks., is an important disease affecting durum wheat (Triticum turgidum ssp. durum) worldwide, particularly in the Mediterranean region. The disease can be controlled through the use of plant host resistance. Based on seedling resistance tests of 103 durum genotypes against a bulk of ...

  16. A stochastic model simulating the spatiotemporal dynamics of yellow rust on wheat

    DEFF Research Database (Denmark)

    Lett, C.; Østergård, Hanne

    2000-01-01

    A stochastic model of the spatiotemporal dynamics of plant disease epidemics in monocultures is described and applied to the simulation of yellow rust on wheat (Puccinia striiformis f. sp. tritici). The most sensitive parameters of the model are latent period, daily multiplication factor...

  17. Prehaustorial and posthaustorial resistance to wheat leaf rust in diploid wheat

    NARCIS (Netherlands)

    Anker, C.C.

    2001-01-01

    In modern wheat cultivars, resistance to wheat leaf rust, Puccinia triticina , is either based on hypersensitivity resistance or on partial resistance. Hypersensitivity resistance in wheat is monogenic, often complete and posthaustorial: it is induced after the

  18. Studies of the genetics of inheritance of stem rust resistance in ...

    African Journals Online (AJOL)

    User

    2013-05-22

    May 22, 2013 ... develop genetic populations for determining the inheritance of resistance to stem rust. F3 populations were evaluated at KARI ... effector molecule of the host plant could lead to a change from avirulent to virulent forms. ... understanding of the genetics of disease resistance and use of appropriate crosses in ...

  19. Severity of angular leaf spot and rust diseases on common beans in ...

    African Journals Online (AJOL)

    ACSS

    Angular leaf spot and rust of common beans can be controlled using fungicides, resistant varieties, biological control and cultural practices such as intercropping, crop rotation, optimum plant spacing and use of soil amendments that promote soil health and plant nutrition. In Uganda, the use of fungicide is limited to common ...

  20. Histology of white pine blister rust in needles of resistant and susceptible eastern white pine

    Science.gov (United States)

    Joel A. Jurgens; Robert A. Blanchette; Paul J. Zambino; Andrew David

    2003-01-01

    White pine blister rust, Cronartium ribicola, has plagued the forests of North America for almost a century. Over past decades, eastern white pine (Pinus strobus) that appear to tolerate the disease have been selected and incorporated into breeding programs. Seeds from P. strobus with putative resistance were...

  1. The influence of white pine blister rust on seed dispersal in whitebark pine

    Science.gov (United States)

    Shawn T. McKinney; Diana F. Tomback

    2007-01-01

    We tested the hypotheses that white pine blister rust (Cronartium ribicola J.C. Fisch.) damage in whitebark pine (Pinus albicaulis Engelm.) stands leads to reduced (1) seed cone density, (2) predispersal seed survival, and (3) likelihood of Clark's Nutcracker (Nucifraga columbiana (Wilson, 1811)) seed...

  2. Resistance to the soybean rust pathogen (Phakopsora Pachyrhizi) in common bean cultivar CNC

    Science.gov (United States)

    Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a new disease in the Americas that has moved swiftly from one country to another. P. pachyrhizi was first reported on soybeans in Paraguay (2001) and soon after in Brazil and Argentina (2002), Bolivia (2003), Uruguay and the USA, (2004), and M...

  3. Harvest intensity and competition control impacts on loblolly pine fusiform rust incidence

    Science.gov (United States)

    Robert J. Eaton; Paula Spaine; Felipe G. Sanchez

    2006-01-01

    The Long Term Soil Productivity experiment tests the effects of soil compaction, surface organic matter removal, and understory control on net primary productivity. An unintended consequence of these treatments may be an effect on the incidence of fusiform rust [Cronartium quercuum (Berk.) Miy. ex Shirai f. sp. fusiforme Burdsall et Snow]. Loblolly pine (Pinus...

  4. Sources of stem rust resistance in wheat-alien introgression lines

    Science.gov (United States)

    Stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most devastating diseases of wheat and the novel highly virulent race of TTKSK and its lineage are threatening wheat production worldwide. The objective of the study was to identify new sources of resistance in wheat-alien introgre...

  5. First Report of Garlic Rust Caused by Puccinia allii on Allium sativum in Minnesota

    Science.gov (United States)

    In July 2010, Allium sativum, cultivar German Extra Hardy Porcelain plants showing foliar symptoms typical of rust infection were brought to the Plant Disease Clinic at the University of Minnesota by a commercial grower from Fillmore county Minnesota. Infected leaves showed circular to oblong lesio...

  6. Molecular mapping of a stripe rust resistance gene in wheat line C51

    Indian Academy of Sciences (India)

    Stripe rust, a major disease in areas where cool temperatures prevail, can strongly influence grain yield. To control this disease, breeders have incorporated seedling resistance genes from a variety of sources outside the primary wheat gene pool. The wheat line C51, introduced from the International Center for Agricultural ...

  7. Conservation of biodiversity in sugar pine: effects of the blister rust epidemic on genetic diversity

    Science.gov (United States)

    Constance I. Millar; Bohun B. Kinloch; Robert D. Westfall

    1992-01-01

    Genetic diversity in sugar plne will be severely reduced by the blister rust pandemic predicted within the next 50 to 75 years. We model effects of the epidemic on genetic diversity at the stand and landscape levels for both natural and artificial regeneration. In natural stands, because natural frequencies of the dominant gene (R) for resistance are low, the most...

  8. Selection for resistance to white pine blister rust affects the abiotic stress tolerances of limber pine

    Science.gov (United States)

    Patrick J. Vogan; Anna W. Schoettle

    2015-01-01

    Limber pine (Pinus flexilis) mortality is increasing across the West as a result of the combined stresses of white pine blister rust (Cronartium ribicola; WPBR), mountain pine beetle (Dendroctonus ponderosae), and dwarf mistletoe (Arceuthobium cyanocarpum) in a changing climate. With the continued spread of WPBR, extensive mortality will continue with strong selection...

  9. Secondary metabolites from the saprotrophic fungus Granulobasidium vellereum

    OpenAIRE

    Nord, Christina

    2014-01-01

    The production of secondary metabolites by the saprotrophic fungus Granulobasidium vellereum was investigated. G. vellereum is a wood decomposing basidiomycete fungus that arrives at dead trunks of fallen hard wood trees at a later stage of the decomposition process and hence need to outcompete the organisms already colonizing the site. It was hypothesised that part of the fungus competitive ability was based on the production of secondary metabolites. In total, 33 secondary metabolites, ...

  10. Proteomic characterization of the Rph15 barley resistance gene-mediated defence responses to leaf rust

    Directory of Open Access Journals (Sweden)

    Bernardo Letizia

    2012-11-01

    Full Text Available Abstract Background Leaf rust, caused by the biotrophic fungal pathogen Puccinia hordei, is one of the most important foliar disease of barley (Hordeum vulgare and represents a serious threat in many production regions of the world. The leaf rust resistance gene Rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 Puccinia hordei isolates collected from around the world. Molecular and biochemical mechanisms responsible for the Rph15 effectiveness are currently not investigated. The aim of the present work was to study the Rph15-based defence responses using a proteomic approach. Results Protein pattern changes in response to the leaf rust pathogen infection were investigated in two barley near isogenic lines (NILs, Bowman (leaf rust susceptible and Bowman-Rph15 (leaf rust resistant, differing for the introgression of the leaf rust resistance gene Rph15. Two infection time points, 24 hours and four days post inoculation (dpi, were analysed. No statistically significant differences were identified at the early time point, while at 4 dpi eighteen protein spots were significantly up or down regulated with a fold-change equal or higher than two in response to pathogen infection. Almost all the pathogen-responsive proteins were identified in the Bowman-Rph15 resistant NIL. Protein spots were characterized by LC-MS/MS analysis and found to be involved in photosynthesis and energy metabolism, carbohydrate metabolism, protein degradation and defence. Proteomic data were complemented by transcriptional analysis of the respective genes. The identified proteins can be related to modulation of the photosynthetic apparatus components, re-direction of the metabolism to sustain defence responses and deployment of defence proteins. Conclusions The identification of leaf rust infection-modulated defence responses restricted to the resistant NIL support the hypothesis that basal defence responses of Bowman, but not the

  11. Appraisal of wheat germplasm for adult plant resistance against stripe rust

    Directory of Open Access Journals (Sweden)

    Saleem Kamran

    2015-12-01

    Full Text Available The resurgence of wheat stripe rust is of great concern for world food security. Owing to resistance breakdown and the appearance of new virulent high-temperature adapted races of Puccinia striiformis f. sp. tritici (Pst, many high yielding commercial varieties in the country lost their yield potential. Searching for new sources of resistance is the best approach to mitigate the problem. Quantitative resistance (partial or adult plant or durable resistance is reported to be more stable than race specific resistance. In the current perusal, a repertoire of 57 promising wheat lines along with the KLcheck line Morocco, developed through hybridisation and selection of local and international lines with International Maize and Wheat Improvement Center (CIMMYT origin, were evaluated under natural field conditions at Nuclear Institute for Agriculture and Biology (NIAB during the 2012−2013 and 2013−2014 time periods. Final rust severity (FRS, the area under the rust progress curve (AURPC, the relative area under the rust progress curve (rAURPC, and the coefficient of infection (CI were unraveled to infer the level of quantitative resistance. Final rust severity was recorded when the susceptible check exhibited 100% severity. There were 21 lines which were immune (no disease, 16 which were resistant, five moderately resistant, two resistant-to-moderately resistant, one moderately resistant-to-moderately susceptible, 5 moderately susceptible-to-susceptible, one moderately susceptible, and six exhibited a susceptible response. Nevertheless, 51 lines exhibited a high level of partial resistance while the three lines, NW-5-1212-1, NW-7-30-1, and NW-7-5 all showed a moderate level of partial resistance based on FRS, while 54 lines, on the basis of AURPC and rAURPC, were identified as conferring a high level of partial resistance. Moreover, adult plant resistance was conferred by 47 wheat lines, based on CI value. It was striking that, 13 immune lines

  12. Stem rust (Puccinia graminis ssp. graminicola Urban its hosts and harmfulness in grasses grown for seed

    Directory of Open Access Journals (Sweden)

    Maria Prończuk

    2013-12-01

    Full Text Available Stem rust development on four species of grasses was studied in field experiments conducted at Radzików in 1997-2001. Population of Puccinia graminis ssp. graminicola from different hosts was characterised and their harmfulness for grass grown for seed was estimated. The materials for study were ecotypes and strains of Lolium perenne, Festuca rubra, Poa pratensis and Deschampsia caespitosa collected in breeding nursery and cultivars and strains of L.perenne, F.rubra, P.pratensis cultivated for seed. It was found that the changes in environmental conditions during last years influenced earlier occurrence of stem rust on grasses in Poland. All examined species were the host of P.graminis ssp. graminicola, however the period of infection of particular hosts were different. L.perenne and D.caespitosa were infected in early summer but F.rubra and P.pratensis in late summer or in the autumn. Morphological analysis of spores of P.graminis ssp. graminicola have shoved significant differences between populations obtained from L.perenne and D.caespitosa. Some differences were found between populations from F.rubra and P.pratensis also, but they need more study. Every year occurrence of stem rust on L.perenne and D.caespitosa and its relation with spring temperature in Radzików indicated that populations of patogen could overwinter in local turf. Incidental appearance of stem rust on F.rubra and P.pratensis in centre of Poland allowed to suppose that spores of these forms might be transfer by wind from other regions. The investigation revealed that stem rust can be dangerous for L.perenne grown for seed when infection occurs at flowering time. It has been established that infection of F.rubra and P.pratensis in autumn should not be disregarded. Damages of leaves by P.graminis ssp. graminicola substantially limited plant heading in the next year.

  13. Pushing the boundaries of resistance: insights from Brachypodium-rust interactions

    Directory of Open Access Journals (Sweden)

    Melania eFigueroa

    2015-07-01

    Full Text Available The implications of global population growth urge transformation of current food and bioenergy production systems to sustainability. Members of the family Poaceae are of particular importance both in food security and for their applications as biofuel substrates. For centuries, rust fungi have threatened the production of valuable crops such as wheat, barley, oat and other small grains; similarly, biofuel crops can also be susceptible to these pathogens. Emerging rust pathogenic races with increased virulence and recurrent rust epidemics around the world point out the vulnerability of monocultures. Basic research in plant immunity, especially in model plants, can make contributions to understanding plant resistance mechanisms and improve disease management strategies. The development of the grass Brachypodium distachyon as a genetically tractable model for monocots, especially temperate cereals and grasses, offers the possibility to overcome the experimental challenges presented by the genetic and genomic complexities of economically valuable crop plants. The numerous resources and tools available in Brachypodium have opened new doors to investigate the underlying molecular and genetic bases of plant-microbe interactions in grasses and evidence demonstrating the applicability and advantages of working with B. distachyon is increasing. Importantly, several interactions between B. distachyon and devastating plant pathogens, such rust fungi, have been examined in the context of non-host resistance. Here, we discuss the use of B. distachyon in these various pathosystems. Exploiting B. distachyon to understand the mechanisms underpinning disease resistance to non-adapted rust fungi may provide effective and durable approaches to fend off these pathogens. The close phylogenetic relationship among Brachypodium spp. and grasses with industrial and agronomic value support harnessing this model plant to improve cropping systems and encourage its use in

  14. Resistance to recombinant stem rust race TPPKC in hard red spring wheat.

    Science.gov (United States)

    Klindworth, D L; Miller, J D; Williams, N D; Xu, S S

    2011-08-01

    The wheat (Triticum aestivum L.) stem rust (Puccinia graminis Pers.:Pers. f.sp. tritici Eriks. and Henn.) resistance gene SrWld1 conditions resistance to all North American stem rust races and is an important gene in hard red spring (HRS) wheat cultivars. A sexually recombined race having virulence to SrWld1 was isolated in the 1980s. Our objective was to determine the genetics of resistance to the race. The recombinant race was tested with the set of stem rust differentials and with a set of 36 HRS and 6 durum cultivars. Chromosomal location studies in cultivars Len, Coteau, and Stoa were completed using aneuploid analysis, molecular markers, and allelism tests. Stem rust differential tests coded the race as TPPKC, indicating it differed from TPMKC by having added virulence on Sr30 as well as SrWld1. Genes effective against TPPKC were Sr6, Sr9a, Sr9b, Sr13, Sr24, Sr31, and Sr38. Genetic studies of resistance to TPPKC indicated that Len, Coteau, and Stoa likely carried Sr9b, that Coteau and Stoa carried Sr6, and Stoa carried Sr24. Tests of HRS and durum cultivars indicated that five HRS and one durum cultivar were susceptible to TPPKC. Susceptible HRS cultivars were postulated to have SrWld1 as their major stem rust resistance gene. Divide, the susceptible durum cultivar, was postulated to lack Sr13. We concluded that although TPPKC does not constitute a threat similar to TTKSK and its variants, some cultivars would be lost from production if TPPKC became established in the field.

  15. Effect of solar radiation on severity of soybean rust.

    Science.gov (United States)

    Young, Heather M; George, Sheeja; Narváez, Dario F; Srivastava, Pratibha; Schuerger, Andrew C; Wright, David L; Marois, James J

    2012-08-01

    Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging fungal disease of soybean (Glycine max). Although solar radiation can reduce SBR urediniospore survival, limited information is available on how solar radiation affects SBR progress within soybean canopies. Such information can aid in developing accurate SBR prediction models. To manipulate light penetration into soybean canopies, structures of shade cloth attenuating 30, 40, and 60% sunlight were constructed over soybean plots. In each plot, weekly evaluations of severity in lower, middle, and upper canopies, and daily temperature and relative humidity were recorded. Final plant height and leaf area index were also recorded for each plot. The correlation between amount of epicuticular wax and susceptibility of leaves in the lower, middle, and upper canopies was assessed with a detached leaf assay. Final disease severity was 46 to 150% greater in the lower canopy of all plots and in the middle canopy of 40 and 60% shaded plots. While daytime temperature within the canopy of nonshaded soybean was greater than shaded soybean by 2 to 3°C, temperatures recorded throughout typical evenings and mornings of the growing season in all treatments were within the range (10 to 28.5°C) for SBR development as was relative humidity. This indicates temperature and relative humidity were not limiting factors in this experiment. Epicuticular wax and disease severity in detached leaf assays from the upper canopy had significant negative correlation (P = 0.009, R = -0.84) regardless of shade treatment. In laboratory experiments, increasing simulated total solar radiation (UVA, UVB, and PAR) from 0.15 to 11.66 MJ m(-2) increased mortality of urediniospores from 2 to 91%. Variability in disease development across canopy heights in early planted soybean may be attributed to the effects of solar radiation not only on urediniospore viability, but also on plant height, leaf area index, and epicuticular wax, which influence

  16. Biological control of yellow rust of wheat (Puccinia striiformis) with Serenade®ASO (Bacillus subtilis strain QST713)

    DEFF Research Database (Denmark)

    Reiss, Antje; Jørgensen, Lise Nistrup

    2017-01-01

    Yellow rust (Puccinia striiformis f. sp. tritici) is an important disease in wheat causing significant yield reductions, if not effectively controlled. The biofungicide Bacillus subtilis strain QST 713 suspension concentrate (Serenade®ASO) was investigated for its potential for yellow rust control...... in winter wheat field trials. Serenade®ASO reduced severity of yellow rust significantly, providing up to 60% control at BBCH growth stage 65–69, under moderate disease pressure. Under high disease pressure reductions were more variable and provided less than 30% control. An increase in the number......®ASO at three dose rates. This trial confirmed the lack of a clear dose response but showed that timing had a major impact on control, with the best control obtained at the day of inoculation. This study revealed that Serenade®ASO cannot stand alone in the control of yellow rust. More research is needed...

  17. Phototaxis in the Marine Fungus Rhizophydium littoreum.

    Science.gov (United States)

    Muehlstein, L K; Amon, J P; Leffler, D L

    1987-08-01

    Phototaxis appears to be a factor that influences the dispersal of zoospores of the marine fungus Rhizophydium littoreum. By using a quantitative method to study phototaxis, zoospores were found to be positively phototactic toward blue wavelengths of light. White light in the range of 20 to 6,000 microeinsteins m s and blue light in the range of 1 to 300 microeinsteins m s gave positive responses in the laboratory. Results of field studies confirmed the ability of zoospores to respond to light under natural conditions. Phototaxis may be an important adaptive mechanism which influences vertical migration of zoospores in the photic zone where plant products are available as nutrients.

  18. Phototaxis in the Marine Fungus Rhizophydium littoreum

    OpenAIRE

    Muehlstein, Lisa K.; Amon, James P.; Leffler, Deborah L.

    1987-01-01

    Phototaxis appears to be a factor that influences the dispersal of zoospores of the marine fungus Rhizophydium littoreum. By using a quantitative method to study phototaxis, zoospores were found to be positively phototactic toward blue wavelengths of light. White light in the range of 20 to 6,000 microeinsteins m−2 s−1 and blue light in the range of 1 to 300 microeinsteins m−2 s−1 gave positive responses in the laboratory. Results of field studies confirmed the ability of zoospores to respond...

  19. Rust Layer Formed on Low Carbon Weathering Steels with Different Mn, Ni Contents in Environment Containing Chloride Ions

    Directory of Open Access Journals (Sweden)

    Gui-qin FU

    2016-11-01

    Full Text Available The rusting evolution of low carbon weathering steels with different Mn, Ni contents under a simulated environment containing chloride ions has been investigated to clarify the correlation between Mn, Ni and the rust formed on steels. The results show that Mn contents have little impact on corrosion kinetics of experimental steels. Content increase of Ni both enhances the anti-corrosion performance of steel substrate and the rust. Increasing Ni content is beneficial to forming compact rust. Semi-quantitative XRD phase analysis shows that the quantity ratio of α/γ*(α-FeOOH/(γ-FeOOH+Fe3O4 decreases as Mn content increases but it increases as Ni content increases. Ni enhances rust layer stability but Mn content exceeding 1.06 wt.% is disadvantageous for rust layer stability. The content increase of Mn does not significantly alter the parameters of the polarization curve. However, as Ni contents increases, Ecorr has shifted to the positive along with decreased icorr values indicating smaller corrosion rate especially as Ni content increases from 0.42 wt.% to 1.50 wt.%.DOI: http://dx.doi.org/10.5755/j01.ms.22.4.12844

  20. Bacterial diversity in the intestinal tract of the fungus- cultivating ...

    African Journals Online (AJOL)

    GREGO

    2007-03-19

    Mar 19, 2007 ... Macrotermes gilvus provides further support for the hypothesis that microorganisms in intestinal tracts of termites ... with their hosts. Key words: Fungus-cultivating termites, bacterial diversity, intestinal tract, 16S rRNA gene, RFLP. ..... Functions of symbiotic fungus gardens in higher termites of the genus.

  1. Phomalactone from a phytopathogenic fungus infecting Zinnia elegans (Asteraceae) leaves

    Science.gov (United States)

    Zinnia elegans plants are infected by a fungus that causes necrosis with dark red spots particularly in late spring to the middle of summer in the Mid-South part of the United States. This fungal disease when untreated causes the leaves to wilt and eventually kills the plant. The fungus was isolated...

  2. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe

    OpenAIRE

    Spitzen-van der Sluijs, Annemarieke; Asselberghs, Johan; Martel, An; Bales, Emma K.; Beukema, Wouter; Bletz, Molly C.; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F.; Nöllert, Andreas; Ohlhoff, Dagmar

    2016-01-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.

  3. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe.

    Science.gov (United States)

    Spitzen-van der Sluijs, Annemarieke; Martel, An; Asselberghs, Johan; Bales, Emma K; Beukema, Wouter; Bletz, Molly C; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F; Nöllert, Andreas; Ohlhoff, Dagmar; Sabino-Pinto, Joana; Schmidt, Benedikt R; Speybroeck, Jeroen; Spikmans, Frank; Steinfartz, Sebastian; Veith, Michael; Vences, Miguel; Wagner, Norman; Pasmans, Frank; Lötters, Stefan

    2016-07-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.

  4. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe

    OpenAIRE

    Spitzen-van der Sluijs, Annemarieke; Martel, An; et al, ...; Schmidt, B R

    2016-01-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010–2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.

  5. [The fungus maitake (Grifola frondosa) and its therapeutic potential].

    Science.gov (United States)

    Illana-Esteban, Carlos

    2008-09-30

    Grifola frondosa (Dicks.) Gray is a polyporaceous fungus and, due to its medical properties, has been used in Eastern cultures for thousands of years. A review of previously published literature on this fungus, its ethnomycological, nutritional, pharmacological and medical aspects were investigated.

  6. Ultastructure of the hyphae of ecfendomycorrhizal fungus of Scotch pine

    Directory of Open Access Journals (Sweden)

    Roman Pachlewski

    2014-08-01

    Full Text Available The analysis of the transverse septa of the mycelium of an ectendomycorrhizal fungus of the pine (strain MrgX 1 using a transmission electron microscope has shown that the septa contain simple pores, which indicates that the fungus belongs to the Ascomycetes.

  7. Putative origins of the fungus Leptographium procerum.

    Science.gov (United States)

    Taerum, Stephen J; Hoareau, Thierry B; Duong, Tuan A; de Beer, Z Wilhelm; Jankowiak, Robert; Wingfield, Michael J

    2017-01-01

    Appropriate management of invasive fungi requires adequate understanding of their global diversities and movement histories. The fungus Leptographium procerum is associated with root-colonizing forest insects in pine forests throughout the world, and may have contributed to the aggressive behaviour of the red turpentine beetle (Dendroctonus valens) in the beetle's invasive range in China. We used microsatellites and mating type loci to investigate the global diversity of L. procerum and the source population of L. procerum associated with D. valens in China. Clustering analyses supported the separation of the fungal data set into three genetically and geographically-distinct clusters: Europe, North America, and China. The fungus had the highest genetic diversity in Europe, followed by North America and China. Analyses using Approximate Bayesian Computation supported Europe as the most likely source of the North American and Chinese populations. Overall, the results suggested that Europe is the global centre of diversity of L. procerum. Furthermore, they suggested that L. procerum most likely arrived in China independently of D. valens and adopted this beetle as a vector after its introduction. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  8. Ribonucleic acids in different tea fungus beverages

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2003-01-01

    Full Text Available In human nutrition, nucleic acids have to be balanced and limited up to 2 g/day because purines are degraded to urate, and excessive production of urate is a cause of gout which primarily affects adult males. Tea fungus beverage is a well known drink with high nutritional value and certain curative effects. Its benefits have been proved in a number of studies but it is still necessary to examine some potential harmful effects of this beverage. The aim of this paper was to investigate content of ribonucleic acids (RNA produced during tea fungus fermentation on a usual substrate sweetened black tea, and on Jerusalem artichoke tubers (J.A.T extract using method by Munro and Fleck (1966. pH, ribonucleic acids and also the production of proteins that affect purity of nucleic acids preparations were monitored. A higher value of RNA has been noticed in J.A.T. beverage (0.57 mg/ml and with observation of usual daily dose of the beverage it is completely safe and useful one.

  9. [Identification and classification of disease severity of wheat stripe rust using near infrared spectroscopy technology].

    Science.gov (United States)

    Li, Xiao-long; Qin, Feng; Zhao, Long-lian; Li, Jun-hui; Ma, Zhan-hong; Wang, Hai-guang

    2015-02-01

    Wheat stripe rust caused by Puccinia striiformis f. sp. tritici, is an economically important disease in the world. It is of great significance to assess disease severity of wheat stripe rust quickly and accurately for monitoring and controlling the disease. In this study, wheat leaves infected with stripe rust pathogen under different severity levels were acquired through artificial inoculation in artificial climate chamber. Thirty wheat leaves with disease severity equal to 1%, 5%, 10%, 20%, 40%, 60%, 80% or 100% were picked out, respectively, and 30 healthy leaves were chosen as controls. A total of 270 wheat leaves were obtained and then their near infrared spectra were measured using MPA spectrometer. According to disease severity levels, 270 near infrared spectra were divided into 9 categories and each category included 30 spectra. From each category, 7 or 8 spectra were randomly chosen to make up the testing set that included 67 spectra. The remaining spectra were treated as the training set. A qualitative model for identification and classification of disease severity of wheat stripe rust was built using near infrared reflectance spectroscopy (NIRS) technology combined with discriminant partial least squares (DPLS). The effects of different preprocessing methods of obtained spectra, ratios between training sets and testing sets, and spectral ranges on qualitative recognition results of the model were investigated. The optimal model based on DPLS was built using cross verification method in the spectral region of 4000-9000 cm(-1) when "centralization" was used as the preprocessing method of spectra and the spectra were divided into the training set and the testing set with the ratio equal to 3:1. Accuracy rate of the training set was 95.57% and accuracy rate of the testing set was 97.01%. The results showed that good recognition performance could be acquired using the model based on DPLS. The results indicated that the method using near infrared reflectance

  10. Kinetics of structural rust transformation in environments containing chloride and SO2

    Directory of Open Access Journals (Sweden)

    Valencia, A.

    2003-12-01

    Full Text Available The behavior of the rusts produced on low carbon steel exposed in industrial atmospheres, at different distances from the sea, was studied by simulating the wetting-drying cycle in a CEBELCOR type apparatus. Coupons electrode potential was monitored and rust layer was analyzed by gravimetric techniques, optical microscopy and Mössbauer spectroscopy. A particular chloride/sulfur ratio in the atmosphere was found, for which there is a particular behavior in rust formation. For this ratio, corrosion rates were much less than expected. It is postulated a kinetic mechanism for rust layer formation as the origin of this special behavior. An electrode potential similar to that in a weathering steel was observed, this is reflected in the low corrosion rate obtained. The proposed kinetic mechanism for rust formation under these exposure conditions enables new research lines on layer formation and the development of protective rust for industrial marine atmospheres.Se estudió el comportamiento de las herrumbres de un acero de bajo carbono expuesto en la simulación de atmósferas industriales con diferentes distancias al mar, con del ciclo de humectación y secado en el ensayo CEBELCOR y en soluciones representativas de las atmósferas en cuestión. Se hizo seguimiento del potencial de electrodo de los cuerpos de prueba y se analizó la capa de productos de corrosión por técnicas gravimétricas, microscopía óptica y espectroscopia Mössbauer. Se determinó un valor de cloruros y sulfatos en la atmósfera que genera un comportamiento particular en la formación de la herrumbre, presentando velocidades de corrosión menores a las esperadas para el tenor de agentes agresivos, y se postuló un mecanismo cinético en la formación de la película como causante del fenómeno particular. Se observó un comportamiento del potencial próximo al de un acero autoprotector, que se refleja en una menor velocidad de corrosión. La propuesta del mecanismo cin

  11. IPR 107 – Dwarf arabic coffee cultivar with resistance to coffee leaf rust

    Directory of Open Access Journals (Sweden)

    Tumoru Sera

    2013-01-01

    Full Text Available ‘IPR 107’ was derived from a cross between ‘IAPAR 59’ and ‘Mundo Novo IAC 376-4’. ‘IPR 107’ is a dwarf medium sizeplant with medium precocity in ripening and with complete resistance to rust races in this time. This cultivar presents superior qualityand high yield in many coffee regions.

  12. Glyphosate inhibits rust diseases in glyphosate-resistant wheat and soybean

    OpenAIRE

    Feng, Paul C. C.; Baley, G. James; Clinton, William P.; Bunkers, Greg J.; Alibhai, Murtaza F.; Paulitz, Timothy C.; Kidwell, Kimberlee K.

    2005-01-01

    Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have shown that glyphosate provided both preventive and curative activities against Puccinia striiformis f. sp. tritici and Puccinia triticina, which cause stripe and leaf rusts, respectively, in wheat. ...

  13. Mapping genes for resistance to stripe rust in spring wheat landrace PI 480035.

    Directory of Open Access Journals (Sweden)

    Jinita Sthapit Kandel

    Full Text Available Stripe rust caused by Puccinia striiformis Westend. f. sp. tritici Erikks. is an economically important disease of wheat (Triticum aestivum L.. Hexaploid spring wheat landrace PI 480035 was highly resistant to stripe rust in the field in Washington during 2011 and 2012. The objective of this research was to identify quantitative trait loci (QTL for stripe rust resistance in PI 480035. A spring wheat, "Avocet Susceptible" (AvS, was crossed with PI 480035 to develop a biparental population of 110 recombinant inbred lines (RIL. The population was evaluated in the field in 2013 and 2014 and seedling reactions were examined against three races (PSTv-14, PSTv-37, and PSTv-40 of the pathogen under controlled conditions. The population was genotyped with genotyping-by-sequencing and microsatellite markers across the whole wheat genome. A major QTL, QYr.wrsggl1-1BS was identified on chromosome 1B. The closest flanking markers were Xgwm273, Xgwm11, and Xbarc187 1.01 cM distal to QYr.wrsggl1-1BS, Xcfd59 0.59 cM proximal and XA365 3.19 cM proximal to QYr.wrsggl1-1BS. Another QTL, QYr.wrsggl1-3B, was identified on 3B, which was significant only for PSTv-40 and was not significant in the field, indicating it confers a race-specific resistance. Comparison with markers associated with previously reported Yr genes on 1B (Yr64, Yr65, and YrH52 indicated that QYr.wrsggl1-1BS is potentially a novel stripe rust resistance gene that can be incorporated into modern breeding materials, along with other all-stage and adult-plant resistance genes to develop cultivars that can provide durable resistance.

  14. FLUXAPYROXAD IN THE ASIAN SOYBEAN RUST CONTROL IN THE CERRADO BIOME

    Directory of Open Access Journals (Sweden)

    RAFAEL MENEZES SILVA DE FREITAS

    2016-01-01

    Full Text Available The etiologic agent of the Asian soybean rust is the Phakopsora pachyrhizi, which causes a reduction in the photosynthetic leaf area and, consequently, in the crop yield. Chemical control is one of the main measures for its management. The objective of this work was to evaluate the efficacy and selectivity of the fluxapyroxad fungicide on controlling the Asian soybean rust, under the edaphoclimatic conditions of the Cerrado biome. The experiment was conducted in an area under no-tillage system, in the Agricultural Research Center, Rio Verde, Goias, Brazil, during the 2012/2013 crop season, using the cultivar NA7337. A randomized block experimental design was used, with twelve treatments and four replications. The treatments consisted of applications of fluxapyroxad (FX, pyraclostrobin (PT, epoxiconazole (EX and metconazole (MZ. The average severity of the disease in the plants reached 37% in the Control. All treatments with fungicides differed from the Control. Treatments 9, 10, 11 and 12 provided the greatest rates of soybean rust control. The treatments 10, 11 and 12 had the highest thousand grain weights, and the yields of the treatments 2, 3 and 11, despite higher than the Control, were lower than the treatments 4, 5, 6, 7, 8, 9, 10 and 12, which had statistically equal yields. The increasing in yield, compared to the Control, ranged from 10.05% (pyraclostrobin, epoxiconazole + pyraclostrobin + mineral oil to 30.55% (pyraclostrobin, pyraclostrobin + fluxapyroxad + mineral oil and pyraclostrobin + metconazole + mineral oil. The highest rates of soybean rust control were presented by fungicides containing fluxapyroxad.

  15. Host specificity and genetic differentiation of Melampsora epitea (rust on willows)

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado Pasten, Sergio [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Plant Pathology and Biocontrol Unit

    2001-07-01

    Rust caused by Melampsora epitea is considered the most serious and widespread disease on willows. When severe, rust can defoliate willows prematurely leading to serious yield losses and rootstock death. Studying the infection process, we found that M. epitea requires no specific recognition signals to germinate, grow, or penetrate the host stomata, regardless of whether interaction with the host plant is compatible or incompatible; instead, plant defense mechanisms are determined by substomatal events. Isolates of the Swedish rust population were classified (pathotyped) by their virulence patterns on a standard set of willow clones (willow differential). Thirty-seven pathotypes of M. epitea were identified and grouped into three formae speciales. For global monitoring of the virulence of M. epitea, an internationally useful naming system was proposed. Partly to confirm the value of such a naming system, the pathotype compositions of two distant M. epitea populations (from Sweden and Chile) were compared using the willow differential. The results indicated that long-distance inocula exchange likely plays an active role in the population dynamics and evolution of pathotype structure for M. epitea. To study the genetics underlying pathotype dynamics, molecular tools, such as AFLP, were used. The resulting dendrogram revealed no clustering based on geographic origin, and because geographic distance among pathogen populations correlated poorly with genetic distance, apparently geographically distant populations have developed collectively as a metapopulation instead of separately. However, the result shows that M. epitea has high levels of gene and genotypic variation within populations, which is consistent with the occurrence of sexual reproduction. The low between-population variation, despite variation in local selection pressures, accords with massive long-distance migration of rust spores.

  16. First report of the white pine blister rust pathogen, Cronartium ribicola, in Arizona

    Science.gov (United States)

    M. L. Fairweather; Brian Geils

    2011-01-01

    White pine blister rust, caused by Cronartium ribicola J.C. Fisch., was found on southwestern white pine (Pinus flexilis James var. reflexa Engelm., synonym P. strobiformis Engelm.) near Hawley Lake, Arizona (Apache County, White Mountains, 34.024°N, 109.776°W, elevation 2,357 m) in April 2009. Although white pines in the Southwest (Arizona and New Mexico) have been...

  17. A simulation model for epidemics of stem rust in ryegrass seed crops.

    Science.gov (United States)

    Pfender, W F; Upper, D

    2015-01-01

    A simulation model (STEMRUST_G, named for stem rust of grasses) was created for stem rust (caused by Puccinia graminis subsp. graminicola) in perennial ryegrass grown to maturity as a seed crop. The model has a daily time step and is driven by weather data and an initial input of disease severity from field observation. Key aspects of plant growth are modeled. Disease severity is modeled as rust population growth, where individuals are pathogen colonies (pustules) grouped in cohorts defined by date of initiation and plant part infected. Infections due to either aerial spread or within-plant contact spread are modeled. Pathogen cohorts progress through life stages that are modeled as disease cycle components (colony establishment, latent period, infectious period, and sporulation) affected by daily weather variables, plant growth, and fungicide application. Fungicide effects on disease cycle components are modeled for two commonly used active ingredients, applied preinfection or postinfection. Previously validated submodels for certain disease cycle components formed the framework for integrating additional processes, and the complete model was calibrated with field data from 10 stem rust epidemics. Discrepancies between modeled outcomes and the calibration data (log10[modeled]-log10[observed]) had a mean near zero but considerable variance, with 1 standard deviation=0.5 log10 units (3.2-fold). It appears that a large proportion of the modeling error variance may be due to variability in field observations of disease severity. An action threshold for fungicide application was derived empirically, using a constructed weather input file favorable for disease development. The action threshold is a negative threshold, representing a level of disease (latent plus visible) below which damaging levels of disease are unable to develop before the yield-critical crop stage. The model is in the public domain and available on the Internet.

  18. Validation of RT-qPCR reference genes for in planta expression studies in Hemileia vastatrix, the causal agent of coffee leaf rust.

    Science.gov (United States)

    Vieira, Ana; Talhinhas, Pedro; Loureiro, Andreia; Duplessis, Sébastien; Fernandez, Diana; Silva, Maria do Céu; Paulo, Octávio S; Azinheira, Helena Gil

    2011-09-01

    Hemileia vastatrix is a biotrophic fungus, causing coffee leaf rust in all coffee growing countries, leading to serious social and economic problems. Gene expression studies may have a key role unravelling the transcriptomics of this pathogen during interaction with the plant host. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is currently the golden standard for gene expression analysis, although an accurate normalisation is essential for adequate conclusions. Reference genes are often used for this purpose, but the stability of their expression levels requires validation under experimental conditions. Moreover, pathogenic fungi undergo important biomass variations along their infection process in planta, which raises the need for an adequate method to further normalise the proportion of fungal cDNA in the total plant and fungus cDNA pool. In this work, the expression profiles of seven reference genes [glyceraldehyde-3-phosphate dehydrogenase (GADPH), elongation factor (EF-1), Beta tubulin (β-tubulin), cytochrome c oxidase subunit III (Cyt III), cytochrome b (Cyt b), Hv00099, and 40S ribosomal protein (40S_Rib)] were analysed across 28 samples, obtained in vitro (germinated uredospores and appressoria) and in planta (post-penetration fungal growth phases). Gene stability was assessed using the statistical algorithms incorporated in geNorm and NormFinder tools. Cyt b, 40S_Rib, and Hv00099 were the most stable genes for the in vitro dataset, while 40S_Rib, GADPH, and Cyt III were the most stable in planta. For the combined datasets (in vitro and in planta), 40S_Rib, GADPH, and Hv00099 were selected as the most stable. Subsequent expression analysis for a gene encoding an alpha subunit of a heterotrimeric G-protein showed that the reference genes selected for the combined dataset do not differ significantly from those selected specifically for the in vitro and in planta datasets. Our study provides tools for correct validation

  19. On the Analysis of the Moessbauer Spectra of the Rust Converted by Tannic and Phosphoric Acids

    Energy Technology Data Exchange (ETDEWEB)

    Barrero, C. A. [Universidad de Antioquia, Grupo de Estado Solido, Instituto de Fisica (Colombia); Rios, J. F. [Universidad de Antioquia, Grupo de Corrosion y Proteccion, Facultad de Ingenierias (Colombia); Morales, A. L. [Universidad de Antioquia, Grupo de Estado Solido, Instituto de Fisica (Colombia); Bohorquez, A.; Perez-Alcazar, G. [Universidad del Valle, Grupo de Metalurgia Fisica y Transiciones de Fase, Departamento de Fisica (Colombia)

    2003-06-15

    In previous work, we reported results on the action of rust converters based on a mixture of tannic and phosphoric acids, upon the rust formed on mild steel coupons. There, the rust before and after the application of converters were characterized by room-temperature Moessbauer spectroscopy, among other techniques. The present work is an extension of this one, and additional MS at 77 K, 130 K and 300 K for some samples are presented. Special emphasis is given to the methodology of analysis. Our results confirm previous findings that an important portion of the magnetite remains without conversion. New information was also derived: (i) the converters seem to affect more the magnetite octahedral (B) than the tetrahedral (A) sites; (ii) among the magnetite B sites, the Fe{sup 2+} is the most affected; (iii) at least 31% of magnetic goethite at 77 K is transformed by the converter; and (iv) the presence of an additional phase identified as ferrous phosphate, could be resolved unambiguously only at these lower temperatures.

  20. Neptunyl (NpO2+) interaction with green rust, GRNa,SO4

    DEFF Research Database (Denmark)

    Christiansen, Bo C.; Geckeis, Horst; Marquardt, Christian

    2011-01-01

    Green rust (GR), a member of the Fe(II),Fe(III) layered double hydroxide mineral family, forms in groundwater and during steel corrosion. It has high surface area and is very reactive, especially for redox-sensitive elements such as some actinides. During neutron irradiation of nuclear fuel......, as are expected from radiolysis in a repository, the very mobile neptunyl-ion, NpO2+, would be the dominant aqueous neptunium species. In this work, we investigated the interaction of NpO2+ with green rust sodium sulphate (GRNa,SO4). The aim of the study was to define the processes involved, to determine...... the final redox speciation of Np, hence its potential mobility, and to characterise changes in the green rust. The GRNa,SO4 sorbed and reduced NpO2+ within minutes. Reduced Np(IV) was primarily found as precipitated nanoparticles at the edges of the GRNa,SO4 crystal platelets. The position of the particles...

  1. Obligate biotrophy features unraveled by the genomic analysis of rust fungi

    Science.gov (United States)

    Duplessis, Sébastien; Cuomo, Christina A.; Lin, Yao-Cheng; Aerts, Andrea; Tisserant, Emilie; Veneault-Fourrey, Claire; Joly, David L.; Hacquard, Stéphane; Amselem, Joëlle; Cantarel, Brandi L.; Chiu, Readman; Coutinho, Pedro M.; Feau, Nicolas; Field, Matthew; Frey, Pascal; Gelhaye, Eric; Goldberg, Jonathan; Grabherr, Manfred G.; Kodira, Chinnappa D.; Kohler, Annegret; Kües, Ursula; Lindquist, Erika A.; Lucas, Susan M.; Mago, Rohit; Mauceli, Evan; Morin, Emmanuelle; Murat, Claude; Pangilinan, Jasmyn L.; Park, Robert; Pearson, Matthew; Quesneville, Hadi; Rouhier, Nicolas; Sakthikumar, Sharadha; Salamov, Asaf A.; Schmutz, Jeremy; Selles, Benjamin; Shapiro, Harris; Tanguay, Philippe; Tuskan, Gerald A.; Henrissat, Bernard; Van de Peer, Yves; Rouzé, Pierre; Ellis, Jeffrey G.; Dodds, Peter N.; Schein, Jacqueline E.; Zhong, Shaobin; Hamelin, Richard C.; Grigoriev, Igor V.; Szabo, Les J.; Martin, Francis

    2011-01-01

    Rust fungi are some of the most devastating pathogens of crop plants. They are obligate biotrophs, which extract nutrients only from living plant tissues and cannot grow apart from their hosts. Their lifestyle has slowed the dissection of molecular mechanisms underlying host invasion and avoidance or suppression of plant innate immunity. We sequenced the 101-Mb genome of Melampsora larici-populina, the causal agent of poplar leaf rust, and the 89-Mb genome of Puccinia graminis f. sp. tritici, the causal agent of wheat and barley stem rust. We then compared the 16,399 predicted proteins of M. larici-populina with the 17,773 predicted proteins of P. graminis f. sp tritici. Genomic features related to their obligate biotrophic lifestyle include expanded lineage-specific gene families, a large repertoire of effector-like small secreted proteins, impaired nitrogen and sulfur assimilation pathways, and expanded families of amino acid and oligopeptide membrane transporters. The dramatic up-regulation of transcripts coding for small secreted proteins, secreted hydrolytic enzymes, and transporters in planta suggests that they play a role in host infection and nutrient acquisition. Some of these genomic hallmarks are mirrored in the genomes of other microbial eukaryotes that have independently evolved to infect plants, indicating convergent adaptation to a biotrophic existence inside plant cells. PMID:21536894

  2. Winter garlic rust (Puccinia spp. rate under organic and conventional production conditions

    Directory of Open Access Journals (Sweden)

    Vlajić Slobodan

    2015-01-01

    Full Text Available Due to low requirements for fertilizers and pesticides, garlic is a valuable crop in organic systems, although production may be hampered by diverse pathogens. In recent years, garlic rust (Puccinia spp. has been increasingly present in our agro-ecological climate, developing into a significant problem for garlic production. The aim of the study was twofold: i to monitor winter garlic rust rate in organic and in conventional production, and ii to monitor genotype sensitivity to the pathogen in both production systems. Trials were conducted in 2012/2013 in Bački Petrovac, Serbia at the Institute of Field and Vegetable Crops in Novi Sad, and included 30 genotypes planted in organic and conventional field, simultaneously. Disease severity was evaluated visually, using a scoring system between zero and five. Overall average infection intensity score in conventional plots was 1.18, and in organic plots 0.79. There was no statistically significant difference between infection intensity in conventional versus organic plots. Nevertheless, reactions of certain genotypes to the causal agents of rust differed across organic and conventional plots ranging from no apparent infection symptoms in organic to severe symptoms in conventional plots.

  3. Laboratory studies using naturally occurring "green rust" to aid metal mine water remediation.

    Science.gov (United States)

    Bearcock, Jenny M; Perkins, William T; Pearce, Nicholas J G

    2011-06-15

    Green rust, an Fe (II) and (III) oxyhydroxy salt, can alter the aqueous oxidation state, mobility and toxicity, of inorganic contaminants and thus could have applications in water treatment. This paper discusses a series of stirred, open batch experiments designed to evaluate green rust, and its oxidised equivalent in this context comparing it to a ferrihydrite/goethite 'ochre'. Natural green rust was added to different mine waters as either a wet, reduced material or a dry, partially oxidised material. Experiments showed that the addition of either form accelerated the removal of potentially harmful elements from solution. Within one hour Fe, Al and Cu were completely removed from mine waters with initial concentrations of 80, 70 and 8.5mg/L, respectively, and Zn was reduced from 60 to mine water treatment, especially as it is able to remove problematic elements such as Al and Zn. The material is effective even after being dried and mostly oxidised. Changes to the pH and ORP of the mine waters and surface catalysis are the suggested mechanisms of accelerated removal of contaminants. Copyright © 2011 NERC. Published by Elsevier B.V. All rights reserved.

  4. Susceptibility levels and grouping of peach cultivars in relation to peach rust under field conditions

    Directory of Open Access Journals (Sweden)

    Giselda Alves

    2014-04-01

    Full Text Available The objective of this study was to assess susceptibility and classify peach cultivars in relation to rust (Tranzschelia discolor under field conditions. The study was conducted in an orchard during the 2007/08 and 2008/09 growing seasons and included the cultivars: Aurora 1, Chimarrita, Chiripá, Coral, Eldorado, Granada, Leonense, Maciel, Marli, Premier and Vanguarda. Several disease-related variables were evaluated, over a 10 day interval from September to February, based on estimates of disease incidence, severity and defoliation. The logistic model adequate fit to rust severity progress data (R2 > 0.90 in the two years. Principal component analysis (PCA using all data, irrespective of the year, identified area under the disease progress curve, initial inoculum and disease progress rate as the best variables to differentiate reactions to rust. When PCA analysis was conducted separately for each year, different disease-related variables were selected as a principal component, and cultivars were classified in three groups of susceptibility. There was inconsistency in the grouping of some cultivars, which was likely due to varying environmental conditions between the years. However, ‘Coral’ was consistently grouped in the low susceptibility group and ‘Chimarrita’ and ‘Granada’ in the high susceptibility group.

  5. Genomic Selection for Quantitative Adult Plant Stem Rust Resistance in Wheat

    Directory of Open Access Journals (Sweden)

    Jessica E. Rutkoski

    2014-11-01

    Full Text Available Quantitative adult plant resistance (APR to stem rust ( f. sp. is an important breeding target in wheat ( L. and a potential target for genomic selection (GS. To evaluate the relative importance of known APR loci in applying GS, we characterized a set of CIMMYT germplasm at important APR loci and on a genome-wide profile using genotyping-by-sequencing (GBS. Using this germplasm, we describe the genetic architecture and evaluate prediction models for APR using data from the international Ug99 stem rust screening nurseries. Prediction models incorporating markers linked to important APR loci and seedling phenotype scores as fixed effects were evaluated along with the classic prediction models: Multiple linear regression (MLR, Genomic best linear unbiased prediction (G-BLUP, Bayesian Lasso (BL, and Bayes Cπ (BCπ. We found the region to play an important role in APR in this germplasm. A model using linked markers as fixed effects in G-BLUP was more accurate than MLR with linked markers (-value = 0.12, and ordinary G-BLUP (-value = 0.15. Incorporating seedling phenotype information as fixed effects in G-BLUP did not consistently increase accuracy. Overall, levels of prediction accuracy found in this study indicate that GS can be effectively applied to improve stem rust APR in this germplasm, and if genotypes at linked markers are available, modeling these genotypes as fixed effects could lead to better predictions.

  6. Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix

    Science.gov (United States)

    Carvalho, Carlos Roberto; Fernandes, Ronaldo C.; Carvalho, Guilherme Mendes Almeida; Barreto, Robert W.; Evans, Harry C.

    2011-01-01

    Background Despite the fact that coffee rust was first investigated scientifically more than a century ago, and that the disease is one of the major constraints to coffee production - constantly changing the socio-economic and historical landscape of the crop - critical aspects of the life cycle of the pathogen, Hemileia vastatrix, remain unclear. The asexual urediniospores are regarded as the only functional propagule: theoretically, making H. vastatrix a clonal species. However, the well-documented emergence of new rust pathotypes and the breakdown in genetic resistance of coffee cultivars, present a paradox. Methods and Results Here, using computer-assisted DNA image cytometry, following a modified nuclear stoichiometric staining technique with Feulgen, we show that meiosis occurs within the urediniospores. Stages of spore development were categorised based on morphology, from the spore-mother cell through to the germinating spore, and the relative nuclear DNA content was quantified statistically at each stage. Conclusions Hidden sexual reproduction disguised within the asexual spore (cryptosexuality) could explain why new physiological races have arisen so often and so quickly in Hemileia vastatrix. This could have considerable implications for coffee breeding strategies and may be a common event in rust fungi, especially in related genera occupying the same basal phylogenetic lineages. PMID:22102860

  7. Bioactive Triterpenes from the Fungus Piptoporus betulinus

    Directory of Open Access Journals (Sweden)

    Zeyad Alresly

    2016-01-01

    Full Text Available Phytochemical investigation of the ethyl acetate extract of the fruiting bodies from the basidiomycete Piptoporus betulinus led to the isolation of a new bioactive lanostane triterpene identified as 3 b -acetoxy-16-hydroxy-24-oxo-5α-lanosta-8- ene-21-oic acid (1. In addition, ten known triterpenes, polyporenic acid A (5, polyporenic acid C (4, three derivatives of polyporenic acid A (8, 10, 11, betulinic acid (3, betulin (2, ergosterol peroxide (6, 9,11-dehydroergosterol peroxide (7, and fomefficinic acid (9, were also isolated from the fungus. All isolated compounds were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria as well as against a fungal strain. The new triterpene and some of the other compounds showed antimicrobial activity against Gram-positive bacteria.

  8. Unusual case of bilateral maxillary fungus ball.

    Science.gov (United States)

    Vinciguerra, Alessandro; Saibene, Alberto Maria; Lozza, Paolo; Maccari, Alberto

    2016-12-15

    An otherwise healthy 34-year-old man was referred to our ear, nose and throat (ENT) clinic for a bilateral maxillary radiologic opacity. This condition was accidentally discovered with a panoramic radiography performed during a follow-up visit after a bilateral endodontic treatment. The patient did not report any specific sinonasal symptom such as purulent nasal discharge, loss of smell and cough, apart from an unspecific sinus pressure. The CT scans showed a bilateral inflammatory process into the maxillary-ethmoidal sinuses and an iron-like density within the maxillary sinuses, while nasal endoscopy showed purulent discharge in the ostiomeatal complex. The patient underwent functional endoscopic sinus surgery under general anaesthesia and the inflammatory material collected was histologically diagnosed as a rare case of bilateral fungus ball. The patient was dismissed the following day with no complications; there were not any sign of recurrence or symptoms during a 4 month follow-up. 2016 BMJ Publishing Group Ltd.

  9. Secondary metabolites from fungus Nigrospora sp.

    Science.gov (United States)

    Chen, Gang; Tian, Li; Wu, Hong-Hua; Bai, Jiao; Lu, Xuan; Xu, Ying; Pei, Yue-Hu

    2012-01-01

    Six compounds were purified from the extracts of fungus Z18-17 (Nigrospora sp.) isolated from Scyphiphora hydrophyllacea, a tree from the intertidal zone of Shankou, Guangxi Province of China, which was reported to have cytotoxic activity. Systematic study on the chemical constituents of Nigrospora sp. resulted in the isolation of one new 6-phenylhexanoic acid derivative, one new derivative of uridine, and four known compounds. Their structures were characterized, respectively, as methyl 5-acetamido-6-(4-hydroxyphenyl)-4-oxohexanoate (1), uridine-5'α-hydroxypropanoate (2), 4-hydroxyphenethyl 2-hydroxypropanoate (3), methyl pyroglutamate (4), cyclo (Pro-Val) (5), and cyclo (Phe-Hyp) (6). The cytotoxic activities of the two new compounds against HL-60 cell line were tested and the IC(50) values of the two new compounds were all over 100 μM.

  10. The mixed mating system of Impatiens capensis and infection by a foliar rust pathogen: patterns of resistance and fitness consequences.

    Science.gov (United States)

    Koslow, Jennifer M; Clay, Keith

    2007-11-01

    Outcrossing by hosts may offer protection from natural enemies adapted to parental genotypes by creating diverse progeny that differ from their parents through genetic recombination. However, past experimental work addressing the relationship between mating system and disease in offspring has given conflicting results, suggesting that outcrossing might also cause the dissolution of resistant genotypes. To determine if selfed progeny are more susceptible to disease caused by the heteroecious rust, Puccinia recondita, or if selfing preserves existing resistant genotypes, we used a factorial design to compare levels of infection of selfed and outcrossed progeny of Impatiens capensis, a woodland annual with a mixed mating system. We compared the level of host infection when exposed to three pathogen sources in the field: the sympatric rust population, and two allopatric rust populations. Outcrossed progeny exposed to sympatric rust had higher infection scores than selfed progeny exposed to the same rust, suggesting that outcrossing breaks up resistant genotypes. In addition, there was a trend for the rust to be more infective on sympatric rather than allopatric hosts. We also examined whether rust infection differentially alters the fitness of selfed and outcrossed progeny. Outcrossed plants that escaped infection had higher fitness, as measured by fruit production, than selfed plants, but there was no difference in fitness between infected selfed and infected outcrossed plants. Thus, outcrossing was advantageous in the absence of disease, but there was no fitness difference between selfed and outcrossed progeny in the presence of disease. In sum, our results indicate that interactions with pathogens can eliminate or reverse the advantage of outcrossing.

  11. Comparative studies of the secretome of fungus-growing ants

    DEFF Research Database (Denmark)

    Linde, Tore; Grell, Morten Nedergaard; Schiøtt, Morten

    2009-01-01

    Leafcutter ants of the species Acromyrmex echinatior live in symbiosis with the fungus Leucoagaricus gongylophorus. The ants harvest fragments of leaves and carry them to the nest where they place the material on the fungal colony. The fungus secretes a wide array of proteins to degrade the leaves...... into nutrients that the ants can feed on. The focus of this study is to discover, characterize and compare the secreted proteins. In order to do so cDNA libraries are constructed from mRNA extracted from the fungus material. The most efficient technology to screen cDNA libraries selectively for secreted...

  12. Recovery plan for Scots pine blister rust caused by Cronartium flaccidum (Alb. & Schwein.) G. Winter and Peridermium pini (Pers.) Lév. [syn. C. asclepiadeum (Willd.) Fr., Endocronartium pini (Pers.) Y. Hiratsuka

    Science.gov (United States)

    Brian W. Geils; Ned B. Klopfenstein; Mee-Sook Kim; Pauline Spaine; Bryce A. Richardson; Paul J. Zambino; Charles G. Shaw; James Walla; Russ Bulluck; Laura Redmond; Kent. Smith

    2009-01-01

    The sexually reproducing form of Scots pine blister rust, C. flaccidum, completes its life cycle alternating between pines of the subgenus Pinus and seed-plants of various families. Scots pine blister rust is also caused by a form of the rust that spreads directly from pine to pine and is named, Peridermium pini...

  13. Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat

    Science.gov (United States)

    Rust diseases caused by Puccinia spp. pose a major threat to global wheat production. Puccinia triticina (Pt), an obligate basidiomycete biotroph, causes leaf rust disease which incurs yield losses of up to 50% in wheat. Historically, resistant wheat cultivars have been used to control leaf rust, bu...

  14. Genetic mapping of rust resistance genes in confection sunflower line HA-R6 and oilseed line RHA 397.

    Science.gov (United States)

    Gong, L; Gulya, T J; Markell, S G; Hulke, B S; Qi, L L

    2013-08-01

    Few widely effective resistance sources to sunflower rust, incited by Puccinia helianthi Schwein., have been identified in confection sunflower (Helianthus annuus L.). The USDA inbred line HA-R6 is one of the few confection sunflower lines resistant to rust. A previous allelism test indicated that rust resistance genes in HA-R6 and RHA 397, an oilseed-type restorer line, are either allelic or closely linked; however, neither have been characterized nor molecularly mapped. The objectives of this study are (1) to locate the rust resistance genes in HA-R6 and RHA 397 on a molecular map, (2) to develop closely linked molecular markers for rust resistance diagnostics, and (3) to determine the resistance spectrum of two lines when compared with other rust-resistant lines. Two populations of 140 F2:3 families each from the crosses of HA 89, as susceptible parent, with HA-R6 and RHA 397 were inoculated with race 336 of P. helianthi in the greenhouse. The resistance genes (R-genes) in HA-R6 and RHA 397 were molecularly mapped to the lower end of linkage group 13, which encompasses a large R-gene cluster, and were designated as R 13a and R 13b, respectively. In the initial maps, SSR (simple sequence repeat) and InDel (insertion and deletion) markers revealed 2.8 and 8.2 cM flanking regions for R 13a and R 13b, respectively, linked with a common marker set of four co-segregating markers, ORS191, ORS316, ORS581, and ZVG61, in the distal side and one marker ORS464 in the proximal side. To identify new markers closer to the genes, sunflower RGC (resistance gene candidate) markers linked to the downy mildew R-gene Pl 8 and located at the same region as R 13a and R 13b were selected to screen the two F2 populations. The RGC markers RGC15/16 and a newly developed marker SUN14 designed from a BAC contig anchored by RGC251 further narrowed down the region flanking R 13a and R 13b to 1.1 and 0.1 cM, respectively. Both R 13a and R 13b are highly effective against all rust races

  15. Molecular characterization of a wheat -Thinopyrum ponticum partial amphiploid and its derived substitution line for resistance to stripe rust.

    Science.gov (United States)

    Hu, Li-Jun; Li, Guang-Rong; Zeng, Zi-Xian; Chang, Zhi-Jian; Liu, Cheng; Yang, Zu-Jun

    2011-08-01

    Stripe rust (caused by Puccinia striiformis) occurs annually in most wheat-growing areas of the world. Thinopyrum ponticum has provided novel rust resistance genes to protect wheat from this fungal disease. Wheat - Th. ponticum partial amphiploid line 7430 and a substitution line X005 developed from crosses between wheat and 7430 were resistant to stripe rust isolates from China. Genomic in situ hybridization (GISH) analysis using Pseudoroegneria spicata genomic DNA as a probe demonstrated that the partial amphiploid line 7430 contained ten J(s) and six J genome chromosomes, and line X005 had a pair of J(s)-chromosomes. Giemsa-C banding further revealed that both lines 7430 and X005 were absent of wheat chromosomes 6B. The EST based PCR confirmed that the introduced J(s) chromosomes belonging to linkage group 6, indicating that line X005 was a 6J(s)/6B substitution line. Both resistance observation and sequence characterized amplified region (SCAR) markers displayed that the introduced chromosomes 6J(s) were responsible for the stripe rust resistances. Therefore, lines 7430 and X005 can be used as a donor in wheat breeding for stripe rust resistance.

  16. Susceptibility to Rust (Puccinia Sp. in Cultivars of Italian and Perennial Ryegrass Grown in Two Locations of Italy

    Directory of Open Access Journals (Sweden)

    Luigi Russi

    2009-03-01

    Full Text Available A large set of foreign varieties of Italian ryegrass (Lolium multiflorum and perennial ryegrass (L. perenne were evaluated for their response to natural rust infection in two Italian locations (Lodi in the north; Perugia in the centre of the country at three-year intervals in 2001, 2004 and 2007, to acquire information on novel germplasm for Italy and verify any spatial and temporal variation in the varietal response to the disease. Crown rust (caused by Puccinia coronata on Italian ryegrass and stem rust (caused by P. graminis on perennial rygrass were consistently recorded in appreciable amount (average susceptibility score > 2.0 on a 1-9 scale. Vice-versa, crown rust on perennial and stem rust on Italian ryegrass seldom affected appreciably the crop. Strong interactions of variety response (to the prevailing pathogen with locations and years of evaluation were observed in both ryegrasses. Subsequently, the repeatability of results between locations, or between years within locations, as measured by rank correlations of variety scores, was sometimes only moderate or low. However, despite such interactions, a few promising varieties were identified in each species with consistently low susceptibility across evaluation environments, which deserve further investigation for a possible direct utilisation, or as donors of useful genes for breeding purposes.

  17. Genome-Wide Association Mapping for Resistance to Leaf and Stripe Rust in Winter-Habit Hexaploid Wheat Landraces.

    Directory of Open Access Journals (Sweden)

    Albert Kertho

    Full Text Available Leaf rust, caused by Puccinia triticina (Pt, and stripe rust, caused by P. striiformis f. sp. tritici (Pst, are destructive foliar diseases of wheat worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst requires a constant search for new sources of resistance. Here we report a genome-wide association analysis of 567 winter wheat (Triticum aestivum landrace accessions using the Infinium iSelect 9K wheat SNP array to identify loci associated with seedling resistance to five races of Pt (MDCL, MFPS, THBL, TDBG, and TBDJ and one race of Pst (PSTv-37 frequently found in the Northern Great Plains of the United States. Mixed linear models identified 65 and eight significant markers associated with leaf rust and stripe rust, respectively. Further, we identified 31 and three QTL associated with resistance to Pt and Pst, respectively. Eleven QTL, identified on chromosomes 3A, 4A, 5A, and 6D, are previously unknown for leaf rust resistance in T. aestivum.

  18. Susceptibility of loblolly x slash pine interspecific F1 hybrids to tip moth infestation and fusiform rust infection in a south Mississippi planting

    Science.gov (United States)

    M.T. Highsmith; L.H. Lott; C.D. Nelson

    2005-01-01

    Tip moth damage and fusiform rust incidence among families of three loblolly pine (Pinus taeda) parent trees from Mississippi, Louisiana, and Texas that were selected for southern pine bark beetle resistance and three slash pines (Pinus elliotti var. elliotti) selected for different levels of fusiform rust resistance, and five of their interspecific...

  19. Blister rust resistance among 19 families of whitebark pine, Pinus albicaulis, from Oregon and Washington – early results from an artificial inoculation trial

    Science.gov (United States)

    Angelia Kegley; Richard A. Sniezko; Robert Danchok; Douglas P. Savin

    2012-01-01

    Whitebark pine is considered one of the most susceptible white pine species to white pine blister rust, the disease caused by the non-native pathogen Cronartium ribicola. High mortality from blister rust and other factors in much of the range in the United States and Canada have raised serious concerns about the future viability of this high-...

  20. QTL-seq approach identified genomic regions and diagnostic markers for rust and late leaf spot resistance in groundnut (Arachis hypogaea L.)

    Science.gov (United States)

    Rust and late leaf spot (LLS) are the two major foliar fungal diseases in groundnut, and their co-occurrence leads to yield loss up to 50–70% in addition to the deterioration of fodder quality. To identify candidate genomic regions controlling rust and LLS resistance, we deployed whole genome re-seq...

  1. Characterization of two adult-plant stripe rust resistance genes on chromosomes 3BS and 4BL in soft red winter wheat

    Science.gov (United States)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important foliar disease of soft red winter wheat (SRWW) in the eastern U.S. However, very few resistance genes have been characterized in the SRWW germplasm pool. The SRWW line VA96W-270 is known to be resistant to stripe rust race P...

  2. Glucoamylase isoform (GAII) purified from a thermophilic fungus ...

    African Journals Online (AJOL)

    Glucoamylase isoform (GAII) purified from a thermophilic fungus Scytalidium thermophilum 15.8 with biotechnological potential. M Cereia, LHS Guimarães, SC Peixoto-Nogueira, JA Jorge, HF Terenzi, LJ Greene, M de Lourdes, TM Polizeli ...

  3. Use of a mobile nursery to obtain a virulence pattern of common bean.

    OpenAIRE

    Steadman, James; Godoy-Lutz, Gabriela; Rosas, Juan Carlos; Beaver, James

    2006-01-01

    As new sources of resistance genes areidentified to rust caused by Uromyces appendiculatus, weneed to know if these genes or others incorporated in the beangermplasm will become susceptible to the pathogen when theresistant varieties are widely grown. We have used a mobilenursery of bean lines/varieties with different rust resistancegenes to answer this question. This nursery, composed of sixday-old bean plants, is placed in a rusted bean field for two tothree hours, misted for 15 hours in a ...

  4. Detection of 3-hydroxykynurenine in a plant pathogenic fungus.

    OpenAIRE

    Wilson, T J Greer; Thomsen, Karl Kristian; Petersen, Bent O.; Duus, Jens Ø.; Oliver, Richard P.

    2003-01-01

    A redox-active compound has been purified from the barley powdery mildew fungus Blumeria ( Erysiphe ) graminis f. sp. hordei. A combination of spectrophotometry, MS and NMR has identified it as 3-hydroxykynurenine (3OHKyn). This compound, never previously detected in any fungus or pathogen, is best known for its role in vertebrate cataracts. It is found abundantly in developing and germinating spores and also in runner hyphae. Two roles for 3OHKyn are discussed: first, the presence of active ...

  5. Solubilization of diabase and phonolite dust by filamentous fungus

    Directory of Open Access Journals (Sweden)

    Juliana Andréia Vrba Brandão

    2014-10-01

    Full Text Available The objective of this study was to evaluate the effect of the fungus Aspergillus niger strain CCT4355 in the release of nutrients contained in two types of rock powder (diabase and phonolite by means of in vitro solubilization trials. The experimental design was completely randomized in a 5 x 4 factorial design with three replications. It was evaluated five treatments (phonolite dust + culture medium; phonolite dust + fungus + culture medium; diabase powder + culture medium; diabase powder + fungus + culture medium and fungus + culture medium and four sampling dates (0, 10, 20 and 30 days. Rock dust (0.4% w/v was added to 125 mL Erlenmeyer flasks containing 50 mL of liquid culture medium adapted to A. niger. The flasks were incubated at 30°C for 30 days, and analysis of pH (in water, titratable acidity, and concentrations of soluble potassium, calcium, magnesium, zinc, iron and manganese were made. The fungus A. niger was able to produce organic acids that solubilized ions. This result indicates its potential to alter minerals contained in rock dust, with the ability to interact in different ways with the nutrients. A significant increase in the amount of K was found in the treatment with phonolite dust in the presence of the fungus. The strain CCT4355 of A. niger can solubilize minerals contained in these rocks dust.

  6. Marker-assisted selection for leaf rust resistance genes Lr19 and Lr24 in wheat (Triticum aestivum L.).

    Science.gov (United States)

    Singh, Rajender; Datta, Dibendu; Priyamvada; Singh, Somvir; Tiwari, Ratan

    2004-01-01

    Leaf rust caused by Puccinia recondita f.sp. tritici is a wheat disease of worldwide importance. Wheat genotypes known to carry specific rust resistance genes and segregating lines that originated from various cross combinations and derived from distinct F2 lineage, so as to represent a diverse genetic background, were included in the present study for validation of molecular markers for Lr19 and Lr24. STS markers detected the presence of the leaf rust resistance gene Lr19 in a Thatcher NIL (Tc*Lrl9) and Inia66//CMH81A575 and of the gene Lr24 in the genotypes Arkan, Blue Boy II, Agent and CI 17907. Validation of molecular markers for Lr19 and Lr24 in parental lines, followed by successful detection of these genes in F3 lines from various cross combinations, was carried out. The molecular test corresponded well with the host-pathogen interaction test response of these lines.

  7. Identification of Nine Pathotype-Specific Genes Conferring Resistance to Fusiform Rust in Loblolly Pine (Pinus taeda L.

    Directory of Open Access Journals (Sweden)

    Henry V. Amerson

    2015-08-01

    Full Text Available Nearly two decades of research on the host-pathogen interaction in fusiform rust of loblolly pine is detailed. Results clearly indicate that pathotype-specific genes in the host interacting with pathogen avirulence cause resistance as defined by the non-gall phenotype under favorable environmental conditions for disease development. In particular, nine fusiform rust resistance genes (Fr genes are described here including the specific methods to determine each and their localization on the reference genetic map of loblolly pine. Understanding how these and other apparent Fr genes in loblolly pine and other rust-susceptible pines impact resistance screening, parental and progeny selection, and family and clonal deployment is an important area in forest genetics research and operational tree breeding. The documentation of these Fr genes is a key piece of information towards gaining that understanding and ultimately improving breeding and deployment strategies.

  8. Secondary metabolites from the fungus Emericella nidulans.

    Science.gov (United States)

    Tarawneh, Amer H; León, Francisco; Radwan, Mohamed M; Rosa, Luiz H; Cutler, Stephen J

    2013-09-01

    A new polyketide derivative koninginin H (1), has been isolated from the fungus Emericella nidulans, together with koninginin E (2), koninginin A (3), trichodermatide B (4), citrantifidiol (5), (4S,5R)-4-hydroxy-5-methylfuran-2-one (6), the glycerol derivatives gingerglycolipid B (7), (2S)-bis[9Z,12Z]-1-O, 2-O-dilinoleoyl-3-O-[alpha-D-galactopyranosyl-(1" --> 6') beta-D-galactopyranosyl]glycerol (8), (2S)-bis[9Z,12Z]-1-O, 2-O-dilinoleoyl-3-O-beta-D-galactopyranosylglycerol (9), the cerebroside flavuside B (10), and the known sterols beta-sitosterol glucoside and ergosta-5,7,22-trien-3-ol. Their structures were established by extensive NMR studies (1H NMR, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC) and mass spectrometry. The antibacterial, antimalarial, antifungal and antileishmanial activities of compounds 1-10 were examined and the results indicated that compound 4 showed good antifungal activity against Cryptococcus neoformans with an IC50 value of 4.9 microg/mL.

  9. RNA-Seq of early-infected poplar leaves by the rust pathogen Melampsora larici-populina uncovers PtSultr3;5, a fungal-induced host sulfate transporter.

    Directory of Open Access Journals (Sweden)

    Benjamin Petre

    Full Text Available Biotroph pathogens establish intimate interactions with their hosts that are conditioned by the successful secretion of effectors in infected tissues and subsequent manipulation of host physiology. The identification of early-expressed pathogen effectors and early-modulated host functions is currently a major goal to understand the molecular basis of biotrophy. Here, we report the 454-pyrosequencing transcriptome analysis of early stages of poplar leaf colonization by the rust fungus Melampsora larici-populina. Among the 841,301 reads considered for analysis, 616,879 and 649 were successfully mapped to Populus trichocarpa and M. larici-populina genome sequences, respectively. From a methodological aspect, these results indicate that this single approach is not appropriate to saturate poplar transcriptome and to follow transcript accumulation of the pathogen. We identified 19 pathogen transcripts encoding early-expressed small-secreted proteins representing candidate effectors of interest for forthcoming studies. Poplar RNA-Seq data were validated by oligoarrays and quantitatively analysed, which revealed a highly stable transcriptome with a single transcript encoding a sulfate transporter (herein named PtSultr3;5, POPTR_0006s16150 showing a dramatic increase upon colonization by either virulent or avirulent M. larici-populina strains. Perspectives connecting host sulfate transport and biotrophic lifestyle are discussed.

  10. Silicato de potássio, acibenzolar-S-metil e fungicidas no controle da ferrugem da soja Potassium silicate, acibenzolar-S-methyl and fungicides on the control of soybean rust

    Directory of Open Access Journals (Sweden)

    Henrique da Silva Silveira Duarte

    2009-11-01

    ência intermediária no controle da ferrugem. O tratamento 6 foi o mais eficiente no controle da doença por resultar nos menores valores da AACPF e Ymax para os terços inferior, médio e superior, além de uma produtividade significativamente maior em relação aos demais tratamentos.Soybean production can be affected by the occurrence of several diseases. Among them, the rust, caused by the fungus Phakopsora pachyrhizi, has been outstanding. Nowadays, new strategies to control soybean rust need to be searched. Therefore, this study aimed to evaluate the efficiency of potassium silicate (KSi, acibenzolar-S-methyl and some fungicides on the control of soybean rust. An experiment was carried out under field conditions in a randomized complete block design with 10 treatments and three replications. The cultivar 'Monarca' was used because it is susceptible to rust. The treatments used were: T1 - control (plants sprayed with water; T2 - KSi (1.2kg ha-1; T3 - KSi (2.4kg ha-1; T4 - KSi (3.6kg ha-1; T5 - KSi (4.8kg ha-1; T6 - tebuconazol (125g de a.i. ha-1; T7 - potassium cloride (61.72g L-1; T8 - mancozeb (2400g de a.i. ha-1; T9 - mancozeb (2400g de a.i. ha-1 + KSi (1.2kg ha-1 and T10 - acibenzolar-S-methyl (125g de a.i. ha-1. Plants from the two lateral lines were inoculated with a suspension of 5x10(5 uredospores/mL at the V4 growth stage to produce inoculum to infect plants at the two central lines. Plants were sprayed with the products that constituted the treatments T2, T3, T4, T5, T7, T8, and T9 at V5, R1, R4, and R5.4 growth stages; and the treatments T6 and T10 at R1, R4, and R5.4 growth stages. Plants were sprayed using a costal sprayer in a volume of 200L ha-1. A total of five disease severity evaluations at the low, medium and high part of the plant canopy were done using a diagrammatic scale ranging from 0.6 to 78.5%. Data were used to calculate the area under rust progress curve (AURPC. There was no effect of the KSi rates on AURPC and final disease severity (Ymax at the

  11. New one-pot synthesis of Au and Ag nanoparticles using green rust reactive particle as a micro-reactor.

    Science.gov (United States)

    Ayadi, Sondra; Perca, Cristian; Legrand, Ludovic

    2013-02-22

    A new, simple, and fast one-pot synthesis of supported Au or Ag nanoparticles is implemented, for which a reactive Fe(II)-bearing green rust inorganic particle is used as an individual micro-reactor acting as both the reducing agent and support for the resulting metal nanoparticles. The mechanism involves both the solid-state oxidation of the green rust support (sulfate or carbonate) and the reduction-precipitation of soluble metal precursor. The resulting nanohybrids have a platy inorganic part supporting about one to ten nanoparticles with sizes in the 20 to 120 nm range.

  12. The revolt of the Rust Belt: place and politics in the age of anger.

    Science.gov (United States)

    McQuarrie, Michael

    2017-11-01

    This paper argues that the election of Donald Trump is the product of a confluence of historical factors rather than the distinctive appeal of the victor himself. By paying particular attention to the geography of unusual voting behaviour the analytical question comes into view: why did so much uncharacteristic voting occur in the Rust Belt states of the upper Midwest? It is impossible to answer this question adequately using conventional categorical attributes. The usual hypotheses of 'economic anxiety' and white revanchism are unable to account for sudden shifts in the voting behaviour of both white and black voters in post-industrial territories. Instead, it is necessary to turn to the history of the region and the institutional apparatus that connected voters there to the federal government and the Democratic Party. From this perspective we can see that the active dismantling of the Fordist social order set the region on a divergent path from the rest of the country. But this path had no political outlet due to the reorientation of the Democratic Party around a new class and geographic base. Due to this, the party pursued policies that would magnify the region's difficulties rather than alleviate its circumstances. Moreover, the elaborate institutional ties that connected the region's voters to the Democratic Party and the federal government meant that the political implications of regional decline would be muted. However, as these institutions frayed, Rust Belt voters were made available to candidates that challenged the policy consensus that had done so much damage to the region. The election was decided by a Rust Belt revolt that unified black and white working-class voters against Hillary Clinton and the Democratic Party. © London School of Economics and Political Science 2017.

  13. Electrochemical formation of green rusts in deaerated seawater-like solutions

    Energy Technology Data Exchange (ETDEWEB)

    Refait, Ph., E-mail: prefait@univ-lr.fr [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Nguyen, D.D. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Hue University' s College of Education, Hue (Viet Nam); Jeannin, M. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Sable, S. [Littoral, Environnement et Societe (LiENSs), UMR 6250, CNRS-Univ. La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Langumier, M. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Littoral, Environnement et Societe (LiENSs), UMR 6250, CNRS-Univ. La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France); Sabot, R. [Laboratoire d' etude des materiaux en milieux agressifs (LEMMA), EA 3167, Universite de La Rochelle, Bat. Marie Curie, Av. Michel Crepeau, F-17 042 La Rochelle Cedex 01 (France); Fed. de Recherche en Environnement et Developpement Durable, FR CNRS 3097 (France)

    2011-07-15

    Highlights: > Sulphated green rust could be electro-generated on carbon steel in anoxic seawater-like electrolytes. > Rust layers grown during 11 years on carbon steel in natural seawater were thoroughly characterised by {mu}-Raman spectroscopy. > The mechanism of marine corrosion of carbon steel in anoxic conditions could be specified. - Abstract: Carbon steel electrodes were polarised at a potential {approx}150 mV higher than the open circuit potential, in a deaerated seawater-like electrolyte (0.5 mol dm{sup -3} NaCl, 0.03 mol dm{sup -3} Na{sub 2}SO{sub 4}, 0.003 mol dm{sup -3} NaHCO{sub 3}). X-ray diffraction and {mu}-Raman analysis demonstrated that a layer mainly composed of GR(SO{sub 4}{sup 2-}) had grown on the steel surface. GR(SO{sub 4}{sup 2-}) was accompanied by traces of GR(CO{sub 3}{sup 2-}). Similar experiments performed in a solution composed of 0.3 mol dm{sup -3} of Na{sub 2}SO{sub 4} and 0.03 mol dm{sup -3} of NaHCO{sub 3} led to the same result. The nature of the GR forming on steel is thus mainly linked to the sulphate to carbonate concentration ratio. Finally, carbon steel coupons immersed for 11 years in the harbour of La Rochelle (Atlantic coast) were removed from seawater for analysis. The inner part of the rust layer proved to be mainly composed of magnetite, GR(SO{sub 4}{sup 2-}) and iron sulphide FeS. This definitively confirms that GR(SO{sub 4}{sup 2-}), as Fe{sub 3}O{sub 4} and FeS, can form from steel in O{sub 2}-depleted environments.

  14. Green rust formation controls nutrient availability in a ferruginous water column

    DEFF Research Database (Denmark)

    Zegeye, Asfaw; Bonneville, Steeve; Benning, Liane G.

    2013-01-01

    a mechanism for reconstructing ancient ocean chemistry. Such reconstructions depend, however, on precise knowledge of the iron minerals formed in the water column. Here, we combine mineralogical and geochemical analyses to demonstrate formation of the mixed-valence iron mineral, green rust, in ferruginous......Iron-rich (ferruginous) conditions were a prevalent feature of the ocean throughout much of Earth's history. The nature of elemental cycling in such settings is poorly understood, however, thus hampering reconstruction of paleoenvironmental conditions during key periods in Earth evolution...

  15. The phytosociology of the De Rust section of the Mountain Zebra National Park, Eastern Cape

    Directory of Open Access Journals (Sweden)

    L.R. Brown

    2000-07-01

    Full Text Available As part of a vegetation survey programme for conservation areas in South Africa, the plant communities of the De Rust section of the Mountain Zebra National Park were investigated. From a TWINSPAN classification, refined by Braun-Blanquet procedures, 14 plant communities, which can be placed into six major groups, were identified. A clas- sification and description of these communities, as well as a vegetation map are presented. Associated gradients in habitat were identified by using an ordination algorithm (DECORANA. The diagnostic species as well as the prominent and less conspicuous species of the tree, shrub, herb and grass strata are outlined.

  16. Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercalated with dodecanoate anions

    DEFF Research Database (Denmark)

    Ayala Luis, Karina Barbara; Ginette Anneliese Cooper, Nicola; Bender Koch, Christian

    2012-01-01

    similar to those found in heavily contaminated groundwater close to polluted industrial sites (14 988 mu M) was reduced mainly to the fully dechlorinated products carbon monoxide (CO, yields >54 and formic acid (HCOOH, yields >6. Minor formation of chloroform (CF), the only chlorinated degradation product......The reductive dechlorination of carbon tetrachloride (CT) by Fe-II-Fe-III hydroxide (green rust) intercalated with dodecanoate, (Fe4Fe2III)-Fe-II (OH)(12)(C12H23O2)(2)center dot gamma H2O (designated GR(C12)), at pH similar to 8 and at room temperature was investigated. CT at concentration levels...

  17. Winter wheat susceptibilty to leaf rust and resistance sources to diseases

    Directory of Open Access Journals (Sweden)

    Jerzy Chełkowski

    2012-12-01

    Full Text Available Winter wheat cultivars were significantly infected by Puccinia triticina causing leaf rust in seasons 2000-2002 in southern and also central regions of Poland. Resistance genes Lr9, Lr19 and Lr24 were found to be effective against dominating populations of the pathogen and typical isolates of P. triticina. Mentioned three resistance genes as well as genes Lr10 and Lr37 were identified using STS (Sequence Tagged Site DNA - PCR markers in cultivars and resistance sources. Mentioned markers were found very useful in resistance breeding of wheat.

  18. Allergens of the entomopathogenic fungus Beauveria bassiana

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    Keyhani Nemat O

    2005-01-01

    Full Text Available Abstract Background Beauveria bassiana is an important entomopathogenic fungus currently under development as a bio-control agent for a variety of insect pests. Although reported to be non-toxic to vertebrates, the potential allergenicity of Beauveria species has not been widely studied. Methods IgE-reactivity studies were performed using sera from patients displaying mould hypersensitivity by immunoblot and immunoblot inhibition. Skin reactivity to B. bassiana extracts was measured using intradermal skin testing. Results Immunoblots of fungal extracts with pooled as well as individual sera showed a distribution of IgE reactive proteins present in B. bassiana crude extracts. Proteinase K digestion of extracts resulted in loss of IgE reactive epitopes, whereas EndoH and PNGaseF (glycosidase treatments resulted in minor changes in IgE reactive banding patterns as determined by Western blots. Immunoblot inhibitions experiments showed complete loss of IgE-binding using self protein, and partial inhibition using extracts from common allergenic fungi including; Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, Candida albicans, Epicoccum purpurascens, and Penicillium notatum. Several proteins including a strongly reactive band with an approximate molecular mass of 35 kDa was uninhibited by any of the tested extracts, and may represent B. bassiana specific allergens. Intradermal skin testing confirmed the in vitro results, demonstrating allergenic reactions in a number of individuals, including those who have had occupational exposure to B. bassiana. Conclusions Beauveria bassiana possesses numerous IgE reactive proteins, some of which are cross-reactive among allergens from other fungi. A strongly reactive potential B. bassiana specific allergen (35 kDa was identified. Intradermal skin testing confirmed the allergenic potential of B. bassiana.

  19. Isolated Polynucleotides and Methods of Promoting a Morphology in a Fungus

    Science.gov (United States)

    Lasure, Linda L [Fall City, WA; Dai, Ziyu [Richland, WA

    2008-10-21

    The invention includes isolated polynucleotide molecules that are differentially expressed in a native fungus exhibiting a first morphology relative to the native fungus exhibiting a second morphology. The invention includes a method of enhancing a bioprocess utilizing a fungus. A transformed fungus is produced by transforming a fungus with a recombinant polynucleotide molecule. The recombinant polynucleotide molecule contains an isolated polynucleotide sequence linked operably to a promoter. The polynucleotide sequence is expressed to promote a first morphology. The first morphology of the transformed fungus enhances a bioprocess relative to the bioprocess utilizing a second morphology.

  20. A survey of poplar (populus nigra rust and identification of fungal agent species with conventional and molecular approaches in Maragheh area of Iran.

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Damadi

    2014-12-01

    Full Text Available In a survey for rust diseases in Maragheh area rust symptoms were observed on poplars (Populus nigra in Maragheh city parks and orchards near the city. Uredinia and urediniospores typical of Melampsora were present on the underside of leaves. Paraphyses were clavate with walls evenly thick and Telia, formed on the leaves early in the autumn, were epiphyllous and subepidermal. DNA was extracted from urediniospores and the primers ITS1 and ITS4 were used to amplify the internal transcribed spacer region of the ribosomal DNA. Based on the key provided by Bagyanarayana and the species description by Pei and Shang, and the result of sequencing, the causal agent was identified as Melampsora allii-populina Kelb. Melampsora species are mainly determined based on their morphology, alternate hosts and telial host range. However, in most cases, only one or two spore stages could be found at the time of observation and there is no information of the alternate hosts. This is the first study of poplar rust disease to the species level in the area. Rust disease is likely to be the most important disease on poplar in this area. As poplar rust can cause severe damages to nursery plants and young trees, there must be further research to understand the epidemiology of the rust disease. A key question to be answered is whether the rust goes through a full life-cycle, possible via known alternate host Allium spp. or only uredinial and telial stages are present in the studied area.

  1. [Medusomyces (tea fungus): scientific history, composition, physiology, and metabolism].

    Science.gov (United States)

    Iurkevich, D I; Kutyshenko, V P

    2002-01-01

    The literature data on medusomyces published since 1913 are discussed. Different versions of appearance and distribution of this microorganism are considered. The features of its structure, metabolism and growth conditions are analyzed. It is shown that the tea fungus is a symbiosis is of several sorts of yeast and acetic acid bacteria. Evidence is presented indicating that fermented tea fungus has a therapeutic effect and can be applied in medicine. It was proved, that the antimicrobial properties of tea fungus metabolic products are due to the presence of particular antibiotic substances. The regularities of the biosynthesis of these substances and the pathways of its stimulation were studied. The results obtained will lead to the large-scale use of tea fungus in biotechnology. The fungus has unique adaptation properties, as confirmed by experiments on cultivation of the organism on deuterium oxide (D2O) and in the conditions of "cold stress". It is suggested that medusomyces is a unique model for the investigation of the phenomenon of symbiosis.

  2. A comparative study of nitrite reduction by synthetic and biogenic Fe(II-III) hydroxysalts green rusts: Evidence for hydroxyl-nitrite green rust formation as an intermediate reaction product.

    Science.gov (United States)

    Ona-Nguema, G.; Guerbois, D.; Morin, G.; Zhang, Y.; Noel, V.; Brest, J.

    2013-12-01

    The occurrence of high nitrite concentrations as a result of anthropogenic activities is an important water quality concern as it is highly toxic to human and fauna, and it is used as a nitrogen source for the assimilation process. The toxicity of nitrite is related to its transformation into carcinogenic N-nitroso compounds, which are suspected to be responsible for some gastric cancers, and to its ability to convert the hemoglobin to methaemoglobin what is then unable to fix oxygen and to transport it to the tissues, involving hypoxia and the blue-baby syndrome [1]. To reduce the adverse effect of nitrite on human health and on macroalgal blooms, any process enhancing the transformation of nitrite ions to nitrogen gas is of interest for the remediation of natural environments. To achieve this purpose the use of processes involving Fe(II)-containing minerals could be considered as one of the best options. Green-rusts are mixed Fe(II-III) layered double hydroxides commonly found in anoxic zones of natural environments such as sediments and hydromorphic soils. In such anoxic environments, green rust minerals play an important role in the biogeochemical redox cycling of iron and nitrogen, and can affect the speciation and mobility of many organic and inorganic contaminants. The present study investigates the reduction of nitrite by two synthetic and two biogenic green rusts. On the one hand, Fe(II-III) hydroxychloride and Fe(II-III) hydroxycarbonate green rusts were used as synthetic interlayer forms of GR, which are referred to as ';syn-GR(CO3)' and ';syn-GR(Cl)', respectively. On the other hand, the study was performed with biogenic Fe(II-III) hydroxycarbonate green rusts obtained from the bioreduction of two ferric precursors, either Fe(III)-oxyhydroxycarbonate or lepidocrocite; these biogenic green rusts are referred to as ';bio-GR(CO3)F' and ';bio-GR(CO3)L', respectively. For synthetic green rusts, results showed that the oxidation of both syn-GR(CO3) and syn

  3. A candidate for Lr19, an exotic gene conditioning leaf rust resistance in wheat.

    Science.gov (United States)

    Gennaro, Andrea; Koebner, Robert M D; Ceoloni, Carla

    2009-08-01

    Lr19, one of the few widely effective genes conferring resistance to leaf rust in wheat, was transferred from the wild relative Thinopyrum ponticum to durum wheat. Since Lr19 confers a hypersensitive response to the pathogen, it was considered likely that the gene would be a member of the major nucleotide-binding site (NBS)-leucine-rich repeat (LRR) plant R gene family. NBS profiling, based on PCR amplification of conserved NBS motifs, was applied to durum wheat-Th. ponticum recombinant lines involving different segments of the alien 7AgL chromosome arm, carrying or lacking Lr19. Differential PCR products were isolated and sequenced. From one such sequence (AG15), tightly linked to Lr19, a 4,121-bp full-length cDNA was obtained. Its deduced 1,258 amino acid sequence has the characteristic NBS-LRR domains of plant R gene products and includes a coiled-coil (CC) region typical of monocots. The genomic DNA sequence showed the presence of two exons and a short intron upstream of the predicted stop codon. Homology searches revealed considerable identity of AG15 with the cloned wheat resistance gene Pm3a and a lower similarity with wheat Lr1, Lr21, and Lr10. Quantitative PCR on leaf-rust-infected and non-infected Lr19 carriers proved AG15 to be constitutively expressed, as is common for R genes.

  4. Molecular cytogenetic characterization and stem rust resistance of five wheat-Thinopyrum ponticum partial amphiploids.

    Science.gov (United States)

    Zheng, Qi; Lv, Zhenling; Niu, Zhixia; Li, Bin; Li, Hongwei; Xu, Steven S; Han, Fangpu; Li, Zhensheng

    2014-11-20

    Partial amphiploids created by crossing common wheat (Triticum aestivum L.) and Thinopyrum ponticum (Podp.) Barkworth & D. R. Dewey are important intermediates in wheat breeding because of their resistance to major wheat diseases. In this study, we examined the chromosome compositions of five Xiaoyan-series wheat-Th. ponticum partial amphiploids (Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430, and Xiaoyan 7631) using GISH, multicolor-GISH, and multicolor-FISH. We found several chromosome changes in these lines. For example, wheat chromosomes 1B and 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively, while wheat chromosome 6B was eliminated from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations, such as A-B and A-D translocations, among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. We also evaluated these partial amphiploids for resistance to nine races of stem rust, including TTKSK (commonly known as Ug99). Three lines, Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430, exhibited excellent resistance to all nine races, and could therefore be valuable sources of stem rust resistance in wheat breeding. Copyright © 2014 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

  5. Resistance to brown leaf rust of hybrids between wheat and amphiploids wheat-thinopyrum

    Directory of Open Access Journals (Sweden)

    Alexander Lvovivh SECHNYAK

    2011-11-01

    Full Text Available The resistance to a brown leaf rust in 56 chromosomal partial аmphiploids (Triticum aestivum L. × Thinopyrum ponticum (Podp. Z.-W. Liu and R.-C. Wang, РА 2 (Triticum aestivum L. × Thinopyrum intermedium (Host Barkworth and D.R. Devey, H79/9-9 (Triticum aestivum L. × Elymus sp., Triticum aestivum L. cvs. Albatross odesskiy, Fantaziya odesskaya, Zhatva Altaya and their hybrids, F2-F4 were studied at artificial infection in field infectious nursery in 2009, 2010 and 2011. The investigated varieties of wheat have shown a high susceptibility to pathogen. Amphiploids РА 1 and РА 2 also are susceptible to pathogen, but in a lesser degree, than the wheat. Good resistance was shown only by amphiploid Н79/9-9, but its hybrid with wheat Albatross Odessa appeared is susceptible to pathogen. The hybrids with amphiploids РА 1 and РА 2 have shown a various degree of resistance to brown leaf rust. Hybrid Zhatva Altaya × РА 2 within three years stably showed 8 point resistance to disease. The reasonsfor different resistance of amphiploids and its hybrids with wheat are discussed.

  6. SH1 leaf rust and bacterial halo blight coffee resistances are genetically independent

    Directory of Open Access Journals (Sweden)

    Lucas Mateus Rivero Rodrigues

    Full Text Available ABSTRACT Coffee resistance to Pseudomonas syringae pv. garcae has been associated to pleiotropic effect of SH1 allele, present in coffee plants resistant to certain races of Hemileia vastatrix, the causal agent of leaf rust, or genetic linkage between resistance alleles to both pathogens. To validate this hypothesis, 63 coffee plants in F2 generation were evaluated for resistance to 2 isolates of H. vastatrix carriers of alleles, respectively, v2, v5 (isolate I/2015 and v1; v2; v5 (isolate II/2015 with the objective to confirm presence of SH1 allele in resistant plants to isolate I/2015. The same coffee plants were evaluated for resistance to a mixture of P. syringae pv. garcae strains highly pathogenic to coffee. Results showed that, among F2 coffee allele SH1 carriers, resistant to isolate I/2015, resistant and susceptible plants to bacterial halo blight were found; the same segregation occurs between F2 homozygous for SH1 allele, susceptible to the same isolate (I/2015 of H. vastatrix. Results also indicate that there is no pleiotropic effect of gene or allele SH1 connection between genes conferring resistance to leaf rust caused by H. vastatrix and bacterial halo blight caused by P. syringae pv. garcae.

  7. Two distinct Ras genes from Puccinia striiformis exhibit differential roles in rust pathogenicity and cell death.

    Science.gov (United States)

    Cheng, Yulin; Wang, Wumei; Yao, Juanni; Huang, Lili; Voegele, Ralf T; Wang, Xiaojie; Kang, Zhensheng

    2016-11-01

    Ras genes have been shown to regulate a variety of cellular processes in higher eukaryotes. However, much less is known about their function(s) in fungi, especially plant pathogenic fungi. Here, we report the identification and functional analysis of Ras genes from Puccinia striiformis f. sp. tritici (Pst), an important fungal pathogen in wheat production worldwide. Pst contains two Ras genes, PsRas1 and PsRas2, which share 48.6% similarity at the protein level and fall into two different phylogenetic clades. Both PsRas1 and PsRas2 have conserved protein sequences among different Pst isolates, but exhibit different transcript profiles during Pst infection. Silencing of PsRas1 or PsRas2 indicates that PsRas2 but not PsRas1 contributes significantly to rust pathogenicity. However, overexpression of PsRas1, but not PsRas2, promotes cell death in yeast and plants. Further studies show that all conserved domains of Ras GTPases in PsRas1 are needed to induce this cell death. In plants, PsRas1-triggered cell death shows similar characteristics as plant hypersensitive response. Our findings suggest that PsRas1 and PsRas2 take over different functions in rust pathogenicity and cell death, thus facilitating the understanding of cell death, pathogenic mechanisms of plant pathogenic fungi and the search for novel pathogen control strategies. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Abstracts of oral and poster presentations given at the 4th Rusts of Forest Trees Conference, Florence, Italy, 3 –6 May 2010

    Directory of Open Access Journals (Sweden)

    AA. VV.

    2011-01-01

    Full Text Available The 4th  International Rusts of Forest Trees Conference was held in Florence, Italy, from May 3 to May 6, 2010. Florence is located in Tuscany, Central Italy, a region which was historically plagued by tree rust outbreaks. More than 40 tree rust specialists from 11 Countries from the northern as well as the southern hemisphere attended the meeting and gave 35 presentations on a broad array of topics, including phylogeny, distribution, biology, epidemiology, genomics, genetic resistance, and management.

  9. An endosymbiotic conidial fungus, Scopulariopsis brevicaulis, protects the American dog tick, Dermacentor variabilis, from desiccation imposed by an entomopathogenic fungus.

    Science.gov (United States)

    Yoder, Jay A; Benoit, Joshua B; Denlinger, David L; Tank, Justin L; Zettler, Lawrence W

    2008-02-01

    The functional role of an endosymbiotic conidial fungus (Scopulariopsis brevicaulis) prevalent within the integumental glands and hemocoel of the American dog tick (Dermacentor variabilis) was investigated to explore the nature of this tick/fungus association. D. variabilis is normally highly resistant to Metarhizium anisopliae, a widely-distributed entomopathogenic fungus, but when mature female ticks harboring S. brevicaulis were fed a solution containing a mycotoxin (Amphotericin B) to purge this mycobiont internally, the ticks inoculated with M. anisopliae displayed classic signs of pathogenicity, as evidenced by recovery of M. anisopliae from ticks by internal fungus culture, greatly accelerated net transpiration water loss rates (nearly 3x faster than ticks containing S. brevicaulis naturally) and elevation of critical equilibrium humidity (CEH) closer to saturation, implying a reduced capacity to absorb water vapor and disruption of water balance (water gain not equal water loss) that resulted in tick death. The presence of S. brevicaulis within the tick was previously puzzling: the fungus is transmitted maternally and there is no apparent harm inflicted to either generation. This study suggests that S. brevicaulis provides protection to D. variabilis ticks against M. anisopliae. Thus, the S. brevicaulis/tick association appears to be mutualistic symbiosis. Given that both organisms are of medical-veterinary importance, disruption of this symbiosis has potential for generating novel tools for disease control.

  10. Metabolite diversification by cultivation of the endophytic fungus Dothideomycete sp. in halogen containing media: Cultivation of terrestrial fungus in seawater.

    Science.gov (United States)

    Wijesekera, Kanchana; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

    2017-06-01

    The endophytic fungus, Dothideomycete sp. CRI7, isolated from the terrestrial plant, Tiliacora triandra, was salt tolerant, capable of growing in the culture medium prepared from seawater; salts in seawater did not have any effects on the fungal growth. Metabolite productions of the fungus CRI7 cultivated in media prepared from seawater (MSW), prepared from deionized water supplemented with potassium bromide (MKBr) or potassium iodide (MKI), and prepared from deionized water (MDW) were investigated. It was found that the cultivation of the fungus CRI7 in MKBr and MSW enabled the fungus to produce nine new metabolites (1-9). The production of an azaphilone, austdiol (10), of the fungus CRI7 grown in MDW was 0.04g/L, which was much lower than that grown in MSW, MKBr, and MKI media which provided the yields of 0.5, 0.9, and 1.2g/L, respectively, indicating that halogen salts significantly enhanced the production of the polyketide 10. The cultivation of terrestrial fungi in media containing halogen salts could therefore be useful for the metabolite diversification by one strain-many compounds (OSMAC) approach. Moreover, the isolated polyketides had significant biosynthetic relationship, suggesting that the cultivation of fungi in halogen containing media could provide the insights into certain polyketide biosynthesis. One of the isolated compounds exhibited antibacterial activity with the MIC value of 100μg/mL. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Random amplified polymorphic DNA markers tightly linked to a gene for resistance to white pine blister rust in sugar pine

    Science.gov (United States)

    Michael E. Devey; Annette Delfino-Mix1; Bohun B. Kinloch; David B. NEALEt

    1995-01-01

    We have genetically mapped a gene for resistance to white pine blister rust (Cronartium ribicola Fisch.) in sugar pine (Pinus lambertiana Dougl.) by using an approach which relies on three factors: (i) the ability to assay for genetic markers in the haploid stage of the host's life cycle, using...

  12. Distribution and frequency of a gene for resistance to white pine blister rust in natural populations of sugar pine

    Science.gov (United States)

    Bohun B. Kinloch Jr.

    1992-01-01

    The gametic frequency of a dominant allcle (R) for resistance to white pine blister rust, a disease caused by an introduced pathogen (Cronartium ribicola), in natural populations of sugar pine was estimated by the kind of leaf symptom expressed after artificial inoculation of wind-pollinated seedlings from susceptible seed-parent...

  13. Rust Formation Mechanism on Low Alloy Steels after Exposure Test in High Cl− and High SOx Environmen

    Directory of Open Access Journals (Sweden)

    Toshiyasu Nishimura

    2017-02-01

    Full Text Available Exposure tests were performed on low alloy steels in high Cl− and high SOx environment, and the structure of the rust were analyzed by TEM (Transmission Electron Microscopy and Raman Spectroscopy. In the exposure test site, the concentrations of Cl− and SOx were found to be high, which caused the corrosion of the steels. The conventional weathering steel (SMA: 0.6% Cr-0.4% Cu-Fe showed higher corrosion resistance as compared to the carbon steel (SM, and Ni bearing steel exhibited the highest one. Raman spectroscopy showed that the inner rust of Ni bearing steel was mainly composed of α-FeOOH and spinel oxides. On the other hand, SMA contained β- and γ-FeOOH in inner rust, which increased the corrosion. TEM showed that nano-scale complex iron oxides containing Ni or Cr were formed in the rust on the low alloy steels, which suppressed the corrosion of steels in high Cl− and high SOx environment.

  14. Using landscape genetics simulations for planting blister rust resistant whitebark pine in the US northern Rocky Mountains

    Science.gov (United States)

    Erin L. Landguth; Zachary A. Holden; Mary F. Mahalovich; Samuel A. Cushman

    2017-01-01

    Recent population declines to the high elevation western North America foundation species whitebark pine, have been driven by the synergistic effects of the invasive blister rust pathogen, mountain pine beetle (MPB), fire exclusion, and climate change. This has led to consideration for listing whitebark pine (WBP) as a threatened or endangered species under the...

  15. Adult plant leaf rust resistance derived from the soft red winter wheat cultivar Caldwell maps to chromosome 3BS

    Science.gov (United States)

    'Caldwell' is a U.S. soft red winter wheat that has partial, adult plant resistance to the leaf rust pathogen Puccinia triticina. A line of 'Thatcher*2/Caldwell' with adult plant resistance derived from Caldwell was crossed with 'Thatcher' to develop a population of recombinant inbred lines (RILs). ...

  16. Constructing high-density genetic maps for polyploid sugarcane (Saccharum spp.) and identifying quantitative trait loci controlling brown rust resistance

    Science.gov (United States)

    Sugarcane (Saccharum spp.) is an important economic crop for producing edible sugar and bioethanol. Brown rust had long been a major disease impacting sugarcane production world widely. Resistance resource and markers linked to the resistance are valuable tools for disease resistance improvement. An...

  17. Evidence of isolate-specificity in non-hypersensitive resistance in spring wheat (Triticum aestivum) to wheat leaf rust

    NARCIS (Netherlands)

    Qamar, Maqsood; Niks, R.E.

    2007-01-01

    Isolate-specific aspect of non-hypersensitive resistance in wheat to wheat leaf rust was studied at seedling stage in the green house. Isolate-specific response of non-hypersensitive resistance was assessed from latency period (LP) and infection frequency (IF) of two single-pustule isolates of

  18. Genome size variation in the pine fusiform rust pathogen Cronartium quercuum f.sp. fusiforme as determined by flow cytometry

    Science.gov (United States)

    Claire L Anderson; Thomas L Kubisiak; C Dana Nelson; Jason A Smith; John M Davis

    2010-01-01

    The genome size of the pine fusiform rust pathogen Cronartium quercuum f.sp. fusiforme (Cqf) was determined by flow cytometric analysis of propidium iodide-stained, intact haploid pycniospores with haploid spores of two genetically well characterized fungal species, Sclerotinia sclerotiorum and Puccinia graminis f.sp. tritici, as size standards. The Cqf haploid genome...

  19. Genome wide association study of seedling and adult plant leaf rust resistance in elite spring wheat breeding lines

    Science.gov (United States)

    Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resista...

  20. On the Rust Products Formed on Weathering and Carbon Steels Exposed to Chloride in Dry-Wet Cyclical Processes

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K. E.; Morales, A. L.; Barrero, C. A., E-mail: cbarrero@fisica.udea.edu.co [Universidad de Antioquia, Grupo de Corrosion y Proteccion, Facultad de Ingenierias (Colombia); Greneche, J. M. [Universite du Maine, Laboratoire de Physique de l' Etat Condense - UMR CNRS 6087 (France)

    2005-02-15

    The rust products formed on weathering and carbon steels exposed to dry-wet cyclical processes in different chloride-rich solutions are carefully examined by means of different techniques. Special emphasis is given to the methodology of analysis of the data using 300 K and 77 K Moessbauer spectrometry and X-ray diffraction. The rust that is loosely bound to the metal surface and that it is lost during the corrosion process, for both types of steel, was found to be composed of lepidocrocite, superparamagnetic goethite, hematite, and traces of akaganeite. On the other hand, the adherent rust, which is differentiated as scraped and hit according to the way it is obtained, from both steels was found to be composed of akaganeite, spinel phase, goethite exhibiting broad distribution of particle sizes and lepidocrocite. The relative abundances of rust components for both steels were very similar, suggesting similar corrosion processes. Mass loss measurements show that the corrosion rates increases with increasing the chloride concentration. The presence of large quantities of spinel phase and akaganeite are a consequence of a corrosion process under the influence of very high chloride concentrations. Our results are useful for assessing the behavior of weathering steels where the levels of chlorides are high or in contact with sea water.

  1. Investigation of Non-Uniform Rust Distribution and Its Effects on Corrosion Induced Cracking in Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Sutrisno Wahyuniarsih

    2017-01-01

    Full Text Available Uniform corrosion still widely used by a lot of researchers and engineers to analyze the corrosion induced cracking. However, in practice, corrosion process occurred non-uniformly. The part nearest to the exposed surface is more likely to have faster corrosion initiation compared with other regions. This research is mainly focused on investigating the effect of non-uniform rust distribution to cover cracking in reinforced concrete. An experimental test performed using accelerated corrosion test by using 5% NaCl solution and applied a constant electric current to the concrete samples. The rust distribution and measurement were observed by using a digital microscope. Based on the experimental result, it was found that the rust was distributed in a non-uniform pattern. As a result, the cracks also formed non-uniformly along the perimeter of steel bar. At the last part of this paper, a simulation result of concrete cracking induced by non-uniform corrosion is presented. The result compared with a simulation using uniform corrosion assumption to investigate the damage pattern of each model. The simulation result reveals stress evolution due to rust expansion which leads to concrete cracking. Furthermore, a comparison of stresses induced by non-uniform corrosion and uniform corrosion indicates that non-uniform corrosion could lead to earlier damage to the structure which is specified by the formation and propagation of the crack.

  2. First report of Puccinia psidii caused rust-disease epiphytotic on the invasive shrub Rhodomyrtus tomentosa in Florida

    Science.gov (United States)

    Rhodomyrtus tomentosa (Aiton) Hassk. (downy-rose myrtle, Family: Myrtaceae) of south Asian origin is an invasive shrub that has formed monotypic stands in Florida. During the winter and spring of 2010-2012, a rust disease of epiphytotic proportion was observed on young foliage, stem terminals and i...

  3. First report of Puccinia psidii caused rust disease epiphytotic on the invasive shrub Rhodomyrtus tomentosa in Florida

    Science.gov (United States)

    M. B. Rayamajhi; P. D. Pratt; N. B. Klopfenstein; A. L. Ross-Davis; L. Rodgers

    2013-01-01

    Rhodomyrtus tomentosa (Aiton) Hassk. (downy-rose myrtle, family: Myrtaceae), of South Asian origin, is an invasive shrub that has formed monotypic stands in Florida (3). During the winter and spring of 2010 through 2012, a rust disease of epiphytotic proportion was observed on young foliage, stem terminals, and immature fruits of this shrub in natural areas of Martin...

  4. Path coefficient analysis of the effects of stripe rust and cultivar mixtures on yield and yield components of winter wheat.

    Science.gov (United States)

    Akanda, S I; Mundt, C C

    1996-05-01

    Four club wheat cultivars and three two-component cultivar mixtures, planted at five frequencies, were grown in three environments in both the presence and absence of stripe rust. The effect of stripe rust on wheat yield was through the yield components, with weight of individual seed being the component most affected by rust. In some cases, yield component compensation was indicated by the presence of negative correlations among the yield components. Path analysis of the yield components revealed that components with the highest correlations to yield also had the largest direct effects on yield. Of the yield components, number of heads per unit area exerted the largest direct influence on yield. The direct effects of number of seeds per head and weight of individual seed were similar, although number of seeds per head was more important in the absence of rust than in its presence. The pure stands and mixtures differed considerably with respect to correlation coefficients, but were very similar for direct effects of yield components on yield. Most of these discrepancies were due to opposing indirect effects, which were not evident from correlation coefficients alone.

  5. Rust Formation Mechanism on Low Alloy Steels after Exposure Test in High Cl− and High SOx Environment

    Science.gov (United States)

    Nishimura, Toshiyasu

    2017-01-01

    Exposure tests were performed on low alloy steels in high Cl− and high SOx environment, and the structure of the rust were analyzed by TEM (Transmission Electron Microscopy) and Raman Spectroscopy. In the exposure test site, the concentrations of Cl− and SOx were found to be high, which caused the corrosion of the steels. The conventional weathering steel (SMA: 0.6% Cr-0.4% Cu-Fe) showed higher corrosion resistance as compared to the carbon steel (SM), and Ni bearing steel exhibited the highest one. Raman spectroscopy showed that the inner rust of Ni bearing steel was mainly composed of α-FeOOH and spinel oxides. On the other hand, SMA contained β- and γ-FeOOH in inner rust, which increased the corrosion. TEM showed that nano-scale complex iron oxides containing Ni or Cr were formed in the rust on the low alloy steels, which suppressed the corrosion of steels in high Cl− and high SOx environment. PMID:28772560

  6. Changing the game: using integrative genomics to probe virulence mechanisms of the stem rust pathogen Puccinia graminis f. sp. tritici

    Science.gov (United States)

    The recent resurgence of wheat stem rust caused by new virulent races of Puccinia graminis f. sp. tritici (Pgt) poses a threat to food security. These concerns have catalyzed an extensive global effort towards controlling this disease. Substantial research and breeding programs target the identifica...

  7. Rust Formation Mechanism on Low Alloy Steels after Exposure Test in High Cl- and High SOx Environmen.

    Science.gov (United States)

    Nishimura, Toshiyasu

    2017-02-17

    Exposure tests were performed on low alloy steels in high Cl- and high SOx environment, and the structure of the rust were analyzed by TEM (Transmission Electron Microscopy) and Raman Spectroscopy. In the exposure test site, the concentrations of Cl- and SOx were found to be high, which caused the corrosion of the steels. The conventional weathering steel (SMA: 0.6% Cr-0.4% Cu-Fe) showed higher corrosion resistance as compared to the carbon steel (SM), and Ni bearing steel exhibited the highest one. Raman spectroscopy showed that the inner rust of Ni bearing steel was mainly composed of α-FeOOH and spinel oxides. On the other hand, SMA contained β- and γ-FeOOH in inner rust, which increased the corrosion. TEM showed that nano-scale complex iron oxides containing Ni or Cr were formed in the rust on the low alloy steels, which suppressed the corrosion of steels in high Cl- and high SOx environment.

  8. First Report of Soybean Rust, Caused by Phakopsora pachyrhizi, on Kudzu (Pueraria montana var. lobata) in Illinois

    Science.gov (United States)

    Soybean rust, caused by Phakopsora pachyrhizi, was first observed on soybean (Glycine max) in the continental United States in Louisiana in 2004, and on kudzu (Pueraria montana var. lobata) in the United States in 2005. Kudzu is a leguminous weed that is prevalent in the southern United States with ...

  9. Genetic diversity of the myrtle rust pathogen (Austropuccinia psidii) in the Americas and Hawaii: Global implications for invasive threat assessments

    Science.gov (United States)

    J. E. Stewart; A.L. Ross-Davis; R. N. Graҫa; A. C. Alfenas; T. L. Peever; J. W. Hanna; J. Y. Uchida; R. D. Hauff; C. Y. Kadooka; M.-S. Kim; P. G. Cannon; S. Namba; S. Simeto; C. A. Pérez; M. B. Rayamajhi; D.J. Lodge; M. Arguedas; R. Medel-Ortiz; M. A. López-Ramirez; P. Tennant; M. Glen; P. S. Machado; A. R. McTaggart; A. J. Carnegie; N. B. Klopfenstein; M. Cleary

    2017-01-01

    Since the myrtle rust pathogen (Austropuccinia psidii) was first reported (as Puccinia psidii) in Brazil on guava (Psidium guajava) in 1884, it has been found infecting diverse myrtaceous species. Because A. psidii has recently spread rapidly worldwide with an extensive host range,...

  10. Effect of partial resistance to barley leaf rust, Puccinia hordei, on the yield of three barley cultivars

    NARCIS (Netherlands)

    Ochoa, J.; Parlevliet, J.E.

    2007-01-01

    Three barley cultivars, Shyri, Clipper and Terán, with different levels of partial resistance to barley leaf rust, caused by Puccinia hordei, were exposed to six levels of the pathogen. These levels were obtained by 5, 4, 3, 2, 1 and 0 fungicide (Propiconazol) applications respectively and occurred

  11. Morphological and molecular characterisation confirm that Triticum monococcum s.s. is resistant to wheat leaf rust

    NARCIS (Netherlands)

    Anker, C.C.; Buntjer, J.B.; Niks, R.E.

    2001-01-01

    The three diploid wheat species Triticum monococcum, Triticum boeoticum and Triticum urartu differ in their reaction to wheat leaf rust, Puccinia triticina. In general, T. monococcum is resistant while T. boeoticum and T. urartu are susceptible. However, upon screening a large collection of diploid

  12. A paradigm shift for white pine blister rust: Non-Ribes alternate hosts for Cronartium ribicola in North America

    Science.gov (United States)

    Paul J. Zambino; Bryce A. Richardson; Geral I. McDonald; Ned B. Klopfenstein; Mee-Sook. Kim

    2007-01-01

    Naturally occurring Cronartium ribicola infections were discovered in August and September, 2004 on Pedicularis racemosa and Castilleja miniata in a mixed stand of white pine blister rust-infected whitebark pine (Pinus albicaulis) and western white pine (P. monticola) in northern Idaho, at Roman Nose Lakes, ca 30 km west of Bonners Ferry. Infections were confirmed by...

  13. Novel QTL for stripe rust resistance on chromosomes 4A and 6B in soft white winter wheat cultivars

    Science.gov (United States)

    Stripe rust (caused by Puccinia striiformis f. sp. tritici) of wheat (Triticum aestivum) is a devastating disease in temperate regions when susceptible varieties are grown and environmental conditions sustain high disease pressures. With frequent and severe outbreaks, disease resistance is a key too...

  14. Status of white pine blister rust and seed collections in california's high-elevation white pine species

    Science.gov (United States)

    J. Dunlap

    2011-01-01

    White pine blister rust (caused by the non-native pathogen Cronartium ribicola) reached northern California about 80 years ago. Over the years its spread southward had been primarily recorded on sugar pine. However, observations on its occurrence had also been reported in several of the higher elevation five-needled white pine species in California. Since the late...

  15. First report of albugo lepidi causing white rust on broadleaved pepperweed (lepidium latifolium) in Nevada and California

    Science.gov (United States)

    The biology and taxonomy of a white rust that is commonly found on the exotic invasive weed Lepidium latifolium were studied in order to assess its potential as a bioherbicide. Previously assumed to be Albugo candida, a common disease of Brassicaceae crops, comparisons of spore morphology and DNA s...

  16. Transcriptome-wide analysis of WRKY transcription factors in wheat and their leaf rust responsive expression profiling.

    Science.gov (United States)

    Satapathy, Lopamudra; Singh, Dharmendra; Ranjan, Prashant; Kumar, Dhananjay; Kumar, Manish; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

    2014-12-01

    WRKY, a plant-specific transcription factor family, has important roles in pathogen defense, abiotic cues and phytohormone signaling, yet little is known about their roles and molecular mechanism of function in response to rust diseases in wheat. We identified 100 TaWRKY sequences using wheat Expressed Sequence Tag database of which 22 WRKY sequences were novel. Identified proteins were characterized based on their zinc finger motifs and phylogenetic analysis clustered them into six clades consisting of class IIc and class III WRKY proteins. Functional annotation revealed major functions in metabolic and cellular processes in control plants; whereas response to stimuli, signaling and defense in pathogen inoculated plants, their major molecular function being binding to DNA. Tag-based expression analysis of the identified genes revealed differential expression between mock and Puccinia triticina inoculated wheat near isogenic lines. Gene expression was also performed with six rust-related microarray experiments at Gene Expression Omnibus database. TaWRKY10, 15, 17 and 56 were common in both tag-based and microarray-based differential expression analysis and could be representing rust specific WRKY genes. The obtained results will bestow insight into the functional characterization of WRKY transcription factors responsive to leaf rust pathogenesis that can be used as candidate genes in molecular breeding programs to improve biotic stress tolerance in wheat.

  17. Exploring the Potential for Actinobacteria as Defensive Symbionts in Fungus-Growing Termites

    NARCIS (Netherlands)

    Visser, A.A.; Mesquita Nobre, T.; Currie, C.R.; Aanen, D.K.; Poulsen, M.

    2012-01-01

    In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a

  18. Carotenoid pigments in the fungus of Coltsfoot (Coleosporium tussilaginis)

    OpenAIRE

    Gavrila NEAMTU; Gh. ILLYES; Maria OTOIU

    1983-01-01

    Investigations were carried out on the carotenoid pigments in the fruiting bodies of the parasitic fungus Coleosporium tussilaginis (Pers.) Kleb., harvested in autumn from the lower mide of the leaves of coltsfoot (Tussilago farfara L.). The fructification of this fungus held only g-carotene and m-carotene. There were found no ranthophylls, epoxides; neither carboxyl nor carboxyl groups. The content of g-carotene was of 22 mg/100 g D.M. and that of b-carotene of 15 mg/100 g D.M. The content o...

  19. Roles of Peroxisomes in the Rice Blast Fungus.

    Science.gov (United States)

    Chen, Xiao-Lin; Wang, Zhao; Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity.

  20. Infection of silkworm larvae by the entomopathogenic fungus Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Lucineia de Fátima Chasko Ribeiro

    Full Text Available ABSTRACT: The isolate E9 of Metarhizium anisopliae was used in commercial hybrids of Bombyx mori larvae to evaluate its biological effect. Symptomatological analyses showed typical signs of fungal infection. Histopathology revealed the presence of large numbers of hemocytes in the hemocoel, and on the sixth dpi the bodies of the insects appeared to be colonised by the fungus. The isolate E9 is pathogenic to larvae B. mori and; therefore, death of the insects was caused by the colonization of fungus in the epidermal and mesodermal tissues.

  1. Patterns of functional enzyme activity in fungus farming ambrosia beetles

    Directory of Open Access Journals (Sweden)

    De Fine Licht Henrik H

    2012-06-01

    Full Text Available Abstract Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae, wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily

  2. Detection of 3-hydroxykynurenine in a plant pathogenic fungus.

    Science.gov (United States)

    Wilson, T J Greer; Thomsen, Karl Kristian; Petersen, Bent O; Duus, Jens Ø; Oliver, Richard P

    2003-05-01

    A redox-active compound has been purified from the barley powdery mildew fungus Blumeria ( Erysiphe ) graminis f. sp. hordei. A combination of spectrophotometry, MS and NMR has identified it as 3-hydroxykynurenine (3OHKyn). This compound, never previously detected in any fungus or pathogen, is best known for its role in vertebrate cataracts. It is found abundantly in developing and germinating spores and also in runner hyphae. Two roles for 3OHKyn are discussed: first, the presence of active oxygen species would enable 3OHKyn to cross-link the spore chemically with the plant. Secondly, it may be acting as an UV protectant and an antioxidant.

  3. Patterns of functional enzyme activity in fungus farming ambrosia beetles

    Science.gov (United States)

    2012-01-01

    Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose

  4. Comparative analysis of secreted protein evolution using expressed sequence tags from four poplar leaf rusts (Melampsora spp.

    Directory of Open Access Journals (Sweden)

    Tanguay Philippe

    2010-07-01

    Full Text Available Abstract Background Obligate biotrophs such as rust fungi are believed to establish long-term relationships by modulating plant defenses through a plethora of effector proteins, whose most recognizable feature is the presence of a signal peptide for secretion. Since the phenotypes of these effectors extend to host cells, their genes are expected to be under accelerated evolution stimulated by host-pathogen coevolutionary arms races. Recently, whole genome sequence data has allowed the prediction of secretomes, facilitating the identification of putative effectors. Results We generated cDNA libraries from four poplar leaf rust pathogens (Melampsora spp. and used computational approaches to identify and annotate putative secreted proteins with the aim of uncovering new knowledge about the nature and evolution of the rust secretome. While more than half of the predicted secretome members encoded lineage-specific proteins, similarities with experimentally characterized fungal effectors were also identified. A SAGE analysis indicated a strong stage-specific regulation of transcripts encoding secreted proteins. The average sequence identity of putative secreted proteins to their closest orthologs in the wheat stem rust Puccinia graminis f. sp. tritici was dramatically reduced compared with non-secreted ones. A comparative genomics approach based on homologous gene groups unravelled positive selection in putative members of the secretome. Conclusion We uncovered robust evidence that different evolutionary constraints are acting on the rust secretome when compared to the rest of the genome. These results are consistent with the view that these genes are more likely to exhibit an effector activity and be involved in coevolutionary arms races with host factors.

  5. Monosomic and molecular mapping of adult plant leaf rust resistance genes in the Brazilian wheat cultivar Toropi.

    Science.gov (United States)

    Da-Silva, P R; Brammer, S P; Guerra, D; Milach, S C K; Barcellos, A L; Baggio, M I

    2012-08-24

    Leaf rust is one of the most destructive diseases affecting wheat worldwide. The most effective way to control it is to use resistant cultivars. Resistance based on slow-rusting adult plant resistance (APR) genes has proven to be the best method for developing cultivars with durable resistance. A source of slow-rusting APR for leaf rust is the Brazilian wheat cultivar Toropi. The Toropi/IAC 13 F₂ and F₇ recombinant inbred lines (RILs) were developed in previous studies. Phenotypic analysis of the F₂ and F₇ RILs showed that 2 recessive genes that were temporarily named trp-1 and trp-2 conferred APR in Toropi. In the present study, we used monosomic families and amplified fragment length polymorphism (AFLP), sequence-tagged site, and simple sequence repeat (SSR) markers to map trp-1 and trp-2 on wheat chromosomes. Analysis of the F₂ monosomic RIL showed that trp- 1 and trp-2 were located on chromosomes 1A and 4D, respectively. AFLP analysis of the F₇ RIL identified 2 independent AFLP markers, XPacgMcac3 and XPacgMcac6, which were associated with Toropi APR. These markers explained 71.5% of the variation in the phenotypic data in a multiple linear regression model. The AFLP markers XPacg/ Mcac3 and XPacg/Mcac6 were anchored by SSR markers previously mapped on the short arms of chromosomes 1A (1AS) and 4D (4DS), respectively. The trp-2 gene is the first leaf rust resistance gene mapped on wheat chromosome 4DS. The mapping of trp-1 and trp-2 provides novel and valuable information that could be used in future studies involving the fine mapping of these genes, as well as in the identification of molecular markers that are closely related to these genes for marker-assisted selection of this important trait in wheat.

  6. TaRar1 Is Involved in Wheat Defense against Stripe Rust Pathogen Mediated by YrSu.

    Science.gov (United States)

    Wang, Xiaojing; Wang, Yaru; Liu, Peng; Ding, Yan; Mu, Xiaoqian; Liu, Xiping; Wang, Xiaojie; Zhao, Mengxin; Huai, Baoyu; Huang, Li; Kang, Zhensheng

    2017-01-01

    RAR1 is a eukaryotic zinc-binding protein first identified as required for race-specific resistance to powdery mildew in barley. To study the function of TaRAR1 involvement in wheat (Triticum aestivum L.) defense against the infection of stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst), we identified and cloned three wheat homeologous genes highly similar to the barley HvRar1, designated as TaRar1-2A, TaRar1-2B, and TaRar1-2D. The three TaRAR1 proteins all contain two conserved cysteine-and histidine-rich domains (CHORD-I and -II) shared by known RAR1-like proteins. Characterization of TaRar1 expression revealed that the expression was tissue-specific and up-regulated in wheat during stripe rust infection. Moreover, the transcription of TaRar1 was induced by methyl jasmonate, ethylene, and abscisic acid hormones. The same results were observed with drought and wound treatments. After TaRar1 was silenced in wheat cultivar Suwon11 containing the stripe rust resistance gene YrSu, the endogenous salicylic acid (SA) level, the hydrogen peroxide (H2O2) accumulation and the degree of hypersensitive response (HR) were significantly decreased, and the resistance to the avirulent pathotype of stripe rust was compromised. Meanwhile, the expression of catalase, an enzyme required for H2O2-scavenging, was up-regulated. Taken together, we concluded that TaRar1 is involved in wheat defense against stripe rust mediated by YrSu, and the defense was through SA to influence reactive oxygen species accumulation and HR.

  7. Seedling Resistance to Stem Rust and Molecular Marker Analysis of Resistance Genes in Wheat Cultivars of Yunnan, China.

    Directory of Open Access Journals (Sweden)

    Tian Ya Li

    Full Text Available Stem rust is one of the most potentially harmful wheat diseases, but has been effectively controlled in China since 1970s. However, the interest in breeding wheat with durable resistance to stem rust has been renewed with the emergence of Ug99 (TTKSK virulent to the widely used resistance gene Sr31, and by which the wheat stem rust was controlled for 40 years in wheat production area worldwide. Yunnan Province, located on the Southwest border of China, is one of the main wheat growing regions, playing a pivotal role in the wheat stem rust epidemic in China. This study investigated the levels of resistance in key wheat cultivars (lines of Yunnan Province. In addition, the existence of Sr25, Sr26, Sr28, Sr31, Sr32, and Sr38 genes in 119 wheat cultivars was assessed using specific DNA markers. The results indicated that 77 (64.7% tested wheat varieties showed different levels of resistance to all the tested races of Puccinia graminis f. sp. tritici. Using molecular markers, we identified the resistance gene Sr31 in 43 samples; Sr38 in 10 samples; Sr28 in 12 samples, and one sample which was resistant against Ug99 (avirulent to Sr32. No Sr25 or Sr26 (effective against Ug99 was identified in any cultivars tested. Furthermore, 5 out of 119 cultivars tested carried both Sr31 and Sr38 and eight contained both Sr31 and Sr28. The results enable the development of appropriate strategies to breed varieties resistant to stem rust.

  8. Optimized integration of T-DNA in the taxol-producing fungus ...

    African Journals Online (AJOL)

    We previously reported a taxol-producing fungus Pestalotiopsis malicola. There, we described the transformation of the fungus mediated by Agrobacterium tumefaciens. T-DNA carrying the selection marker was transferred into the fungus and randomly integrated into the genome as shown by Southern blotting.

  9. Emergence of virulence to SrTmp in the Ug99 race group of wheat stem rust, Puccinia graminis f. sp. tritici, in Africa

    DEFF Research Database (Denmark)

    Patpour, M.; Hovmøller, M. S.; Justesen, A. F.

    2016-01-01

    The Ug99 race (TTKSK) of wheat stem rust was first detected in Uganda in 1998 (Pretorius et al. 2000) and since then, seven additional variants have been reported: TTKSF, TTKST, TTTSK, TTKSP, PTKSK, PTKST, and TTKSF+ (Pretorius et al. 2012). In this study, 84 stem rust samples from the 2014 surveys...... of wheat fields in Africa (Kenya, 9; Uganda, 28; Rwanda, 41; and Egypt, 6) were sent to the Global Rust Reference Center (GRRC, Denmark) for race analysis. Puccinia graminis f. sp. tritici (Pgt) samples were recovered on cv. Morocco, and resulting urediniospores of 53 single-pustule isolates were....... The identification of SrTmp virulence in the Ug99 race group in several countries in one year emphasizes the relevance of coordinated international surveillance efforts and utilization of diverse sources of resistance to control stem rust in wheat. Further studies are in progress to determine the detailed...

  10. Consistent association of fungus Fusarium mangiferae Britz with ...

    African Journals Online (AJOL)

    In exotic ones, maximum and minimum infections of 97.33 and 70.67% were noted in the cultivars Sensation and Pop, respectively. Light and transmission electron microscopy proved helpful in investigating the morphological matrix and ultrastructure of the propagules of fungus F. mangiferae. Key words: Mangifera indica, ...

  11. ligninolytic enzymes of the fungus isolated from soil contaminated ...

    African Journals Online (AJOL)

    FUTE

    laccase and managnese peroxidase production in submerged culture of. Pleurotus sajor-caju. Afr. J. Biotechnol. 10(50): 10166-10177. Revankar MS and Lele SS 2006 Enhanced production of laccase using a new isolate of white rot fungus WR-1. Process Biochem. 41: 581–588. Sasek V, Novotny C and Vampola P 1998.

  12. Lignocellulose pretreatment in a fungus-cultivating termite

    Science.gov (United States)

    Hongjie Li; Daniel J. Yelle; Chang Li; Mengyi Yang; Jing Ke; Ruijuan Zhang; Yu Liu; Na Zhu; Shiyou Liang; Xiaochang Mo; John Ralph; Cameron R. Currie; Jianchu Mo

    2017-01-01

    Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is an essential but challenging starting point for the lignocellulosics industries. The variety of ether– and carbon–carbon interunit linkages produced via radical coupling during lignification limit chemical and biological depolymerization efficiency. In an ancient fungus-cultivating...

  13. Diseases of pines caused by the pitch canker fungus

    Science.gov (United States)

    L. David Dwinell; Stephen W. Fraedrich; D. Adams

    2001-01-01

    Fusarium subglutinans f. sp. pini, the pitch canker fungus, causes a number of serious diseases of Pinus species. The pathogen infects a variety of vegetative and reproductive pine structures at different stages of maturity and produces a diversity of symptoms. When the pathogen infects the woody vegetative...

  14. Aphanomyces frigidophilus , fungus-like organisms isolated from ...

    African Journals Online (AJOL)

    Bait method with the use of hemp seeds Cannabis sativa, small pieces of snake skin Natrix natrix and exuviae of shrimp Gammarus sp. as bait was applied to isolate the fungus Aphanomyces frigidophilus from the springs. The isolate was maintained on Potato Dextrose Agar PDA and stored in the culture collection of the ...

  15. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan

    2011-01-01

    Background: Attine ants live in symbiosis with a basidiomycetous fungus that they rear on a substrate of plant material. This indirect herbivory implies that the symbiosis is likely to be nitrogen deprived, so that specific mechanisms may have evolved to enhance protein availability. We therefore...... of these classes of proteolytic enzymes suggest that substrate specificity may be important and that trade-offs may prevent the simultaneous upregulation of both classes of enzymes.......Background: Attine ants live in symbiosis with a basidiomycetous fungus that they rear on a substrate of plant material. This indirect herbivory implies that the symbiosis is likely to be nitrogen deprived, so that specific mechanisms may have evolved to enhance protein availability. We therefore...... hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...

  16. Directed Evolution of a Filamentous Fungus for Thermotolerance

    Science.gov (United States)

    Filamentous fungi represent the most widely used eukaryotic biocatalysts in industrial and chemical applications. Metarhizium anisopliae is a broad-host-range entomopathogenic fungus currently under intensive investigation as a biologically based alternative to chemical pesticides. One of the most p...

  17. Effect of the Extract of Endophytic fungus, Nigrospora sphaerica CL ...

    African Journals Online (AJOL)

    The effects of extract on ultrastructure of MRSA and K. pneumoniae cells were analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Results: The time-kill ... pneumonia cells. Keywords: Endophytic fungus, Nigrospora sphaerica, Antimicrobial activity, Cellular structure degeneration ...

  18. Comparative nutritional evaluation of fungus and alkali treated rice ...

    African Journals Online (AJOL)

    Treatment of rice husk with fungus (mushroom) increased the nutritive (crude protein and ether extract) value and as the feeding experiment demonstrated, is likely to be a useful method for pre-digesting agricultural waste residues for rumen microbial attack. Keywords: rice husk, Pleurotus sajor caju, intake, digestibility

  19. The origin of Ceratocystis fagacearum, the oak wilt fungus

    Science.gov (United States)

    Jennifer Juzwik; Thomas C. Harrington; William L. MacDonald; David N. Appel

    2008-01-01

    The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes...

  20. Proteomic analysis of the endophytic fungus Undifilum oxytropis | Li ...

    African Journals Online (AJOL)

    The filamentous Ascomycete fungus Undifilum oxytropis is an endophyte of locoweed plants of the genera Oxytropis that produces a toxic alkaloid swainsonine. Swainsonine, an alpha-mannosidase inhibitor causes a general toxicosis and neurological problems (locoism) when consumed by grazing animals. Swainsonine ...