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Sample records for sarothrae downy brome

  1. Distributional changes and range predictions of downy brome (Bromus tectorum) in Rocky Mountain National Park

    Science.gov (United States)

    Bromberg, J.E.; Kumar, S.; Brown, C.S.; Stohlgren, T.J.

    2011-01-01

    Downy brome (Bromus tectorum L.), an invasive winter annual grass, may be increasing in extent and abundance at high elevations in the western United States. This would pose a great threat to high-elevation plant communities and resources. However, data to track this species in high-elevation environments are limited. To address changes in the distribution and abundance of downy brome and the factors most associated with its occurrence, we used field sampling and statistical methods, and niche modeling. In 2007, we resampled plots from two vegetation surveys in Rocky Mountain National Park for presence and cover of downy brome. One survey was established in 1993 and had been resampled in 1999. The other survey was established in 1996 and had not been resampled until our study. Although not all comparisons between years demonstrated significant changes in downy brome abundance, its mean cover increased nearly fivefold from 1993 (0.7%) to 2007 (3.6%) in one of the two vegetation surveys (P = 0.06). Although the average cover of downy brome within the second survey appeared to be increasing from 1996 to 2007, this slight change from 0.5% to 1.2% was not statistically significant (P = 0.24). Downy brome was present in 50% more plots in 1999 than in 1993 (P = 0.02) in the first survey. In the second survey, downy brome was present in 30% more plots in 2007 than in 1996 (P = 0.08). Maxent, a species-environmental matching model, was generally able to predict occurrences of downy brome, as new locations were in the ranges predicted by earlier generated models. The model found that distance to roads, elevation, and vegetation community influenced the predictions most. The strong response of downy brome to interannual environmental variability makes detecting change challenging, especially with small sample sizes. However, our results suggest that the area in which downy brome occurs is likely increasing in Rocky Mountain National Park through increased frequency and cover

  2. Effects of soil amendments on germination and emergence of downy brome (Bromus tectorum) and Hilaria jamesii

    Science.gov (United States)

    Belnap, J.; Sherrod, S.K.; Miller, M.E.

    2003-01-01

    Downy brome is an introduced Mediterranean annual grass that now dominates millions of hectares of western U.S. rangelands. The presence of this grass has eliminated many native species and accelerated wildfire cycles. The objective of this study was to identify soil additives that allowed germination but inhibited emergence of downy brome, while not affecting germination or emergence of the native perennial grass Hilaria jamesii. On the basis of data from previous studies, we focused on additives that altered the availability of soil nitrogen (N), phosphorus (P), and potassium (K). Most water-soluble treatments inhibited downy brome germination and emergence. We attribute the inhibitory effects of these treatments to excessive salinity and ion-specific effects of the additives themselves. An exception to this was oxalic acid, which showed no effect. Most water-insoluble treatments had no effect in soils with high P but did have an effect in soils with low P. Zeolite was effective regardless of P level, probably due to the high amounts of Na+ it added to the soil solution. Most treatments at higher concentrations resulted in lower downy brome emergence rates in soils currently dominated by downy brome than in uninvaded (but theoretically invadable) Hilaria soils. This difference is possibly attributable to inherent differences in labile soil P. In Stifa soils, where Stipa spp. grow, but which are generally considered to be uninvadable by downy brome, additions of high amounts of N resulted in lower emergence. This may have been an effect of NH4+ interference with uptake of K or other cations or toxicity of high N. We also saw a positive relationship between downy brome emergence and pH in Stipa soils. Hilaria development parameters were not as susceptible to the treatments, regardless of concentration, as downy brome. Our results suggest that there are additions that may be effective management tools for inhibiting downy brome in calcareous soils, including (1

  3. Process-based management approaches for salt desert shrublands dominated by downy brome

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    Downy brome grass (Bromus tectorum L.) invasion has severely altered key ecological processes such as disturbance regimes, soil nutrient cycling, community assembly, and successional pathways in semi-arid Great Basin salt desert shrublands. Restoring the structure and function of these severly alte...

  4. Downy Brome (Bromus tectorum L. and Broadleaf Weed Control in Winter Wheat with Acetolactate Synthase-Inhibiting Herbicides

    Directory of Open Access Journals (Sweden)

    Patrick W. Geier

    2013-04-01

    Full Text Available A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS-inhibiting herbicides for downy brome (Bromus tectorum L. and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L., blue mustard [Chorispora tenella (Pallas DC.], and henbit (Lamium amplexicaule L. control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control. Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield.

  5. Low-dose glyphosate does not control annual bromes in the northern Great Plains

    Science.gov (United States)

    Annual bromes (downy brome and Japanese brome) have been shown to decrease perennial grass forage production and alter ecosystem functions in northern Great Plains rangelands. Large-scale chemical control might be a method for increasing rangeland forage production if low application rates confer co...

  6. Suppression of downy brome by red clover as a cover crop

    Science.gov (United States)

    Weeds are one of the primary obstacles to successful organic farming. Organic producers till to control weeds, but soil health is being damaged by the extensive tillage. Therefore, organic producers are interested in reducing the amount of tillage in their production systems. This study examined t...

  7. William L Finley - False Brome Eradication in Mill Hill Unit

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — False Brome is quickly becoming a major threat to the southern end of the refuge with new populations found along hiking trails, spreading into wooded areas via wild...

  8. Identification of brome grass infestations in southwest Oklahoma using multi-temporal Landsat imagery

    Science.gov (United States)

    Yan, D.; de Beurs, K.

    2013-12-01

    The extensive infestation of brome grasses (Cheatgrass, Rye brome and Japanese brome) in southwest Oklahoma imposes negative impacts on local economy and ecosystem in terms of decreasing crop and forage production and increasing fire risk. Previously proposed methodologies on brome grass detection are found ill-suitable for southwest Oklahoma as a result of similar responses of background vegetation to inter-annual variability of rainfall. In this study, we aim to identify brome grass infestations by detecting senescent brome grasses using the 2011 Cultivated Land Cover Data Sets and the difference Normalized Difference Infrared Index (NDII) derived from multi-temporal Landsat imagery. Landsat imageries acquired on May 18th and June 10th 2013 by Operational Land Imager and Enhanced Thematic Mapper plus were used. The imagery acquisition dates correspond to the peak growth and senescent time of brome grasses, respectively. The difference NDII was calculated by subtracting the NDII image acquired in May from the June NDII image. Our hypotheses is that senescent brome grasses and crop/pasture fields harvested between the two image acquisition dates can be distinguished from background land cover classes because of their increases in NDII due to decreased water absorption by senescent vegetation in the shortwave infrared region. The Cultivated Land Cover Data Sets were used to further separate senescent brome grass patches from newly harvested crop/pasture fields. Ground truth data collected during field trips in June, July and August of 2013 were used to validate the detection results.

  9. Preserving prairies: Understanding temporal and spatial patterns of invasive annual bromes in the Northern Great Plains

    Science.gov (United States)

    Ashton, Isabel; Symstad, Amy; Davis, Christopher; Swanson, Daniel J.

    2016-01-01

    Two Eurasian invasive annual brome grasses, cheatgrass (Bromus tectorum) and Japanese brome (Bromus japonicus), are well known for their impact in steppe ecosystems of the western United States where these grasses have altered fire regimes, reduced native plant diversity and abundance, and degraded wildlife habitat. Annual bromes are also abundant in the grasslands of the Northern Great Plains (NGP), but their impact and ecology are not as well studied. It is unclear whether the lessons learned from the steppe will translate to the mixed-grass prairie where native plant species are adapted to frequent fires and grazing. Developing a successful annual brome management strategy for National Park Service units and other NGP grasslands requires better understanding of (1) the impact of annual bromes on grassland condition; (2) the dynamics of these species through space and time; and (3) the relative importance of environmental factors within and outside managers' control for these spatiotemporal dynamics. Here, we use vegetation monitoring data collected from 1998 to 2015 in 295 sites to relate spatiotemporal variability of annual brome grasses to grassland composition, weather, physical environmental characteristics, and ecological processes (grazing and fire). Concern about the impact of these species in NGP grasslands is warranted, as we found a decline in native species richness with increasing annual brome cover. Annual brome cover generally increased over the time of monitoring but also displayed a 3- to 5-yr cycle of reduction and resurgence. Relative cover of annual bromes in the monitored areas was best predicted by park unit, weather, extant plant community, slope grade, soil composition, and fire history. We found no evidence that grazing reduced annual brome cover, but this may be due to the relatively low grazing pressure in our study. By understanding the consequences and patterns of annual brome invasion, we will be better able to preserve and restore

  10. Genetics of resistance against lettuce downy mildew

    Science.gov (United States)

    Lettuce (Lactuca sativa) is one of the most valuable vegetable crops in the U.S. Downy mildew (DM), caused by Bremia lactucae, is the most important foliar disease of lettuce worldwide, which decreases the quality of the marketable portion of the crop. The use of resistant varieties carrying dominan...

  11. Forecasting and management of hop downy mildew

    Science.gov (United States)

    Downy mildew of hop, caused by Pseudoperonospora humuli, is managed in the Pacific Northwestern U.S. by regular application of fungicides. A degree-day model that forecasts the first emergence of shoots systemically infection with P. humuli (termed basal spikes) and a risk index for secondary sprea...

  12. [Competitiveness of hard wheat (Triticum durum Desf.) varieties against ripgut brome (Bromus rigidus Roth)].

    Science.gov (United States)

    Hamal, A; Benbella, M; Rzozi, S B; Bouhache, M; Msatef, Y

    2001-01-01

    Varieties with an excellent competitiveness against ripgut brome (Bromus rigidus Roth.) would be very important to reinforce others methods to control ripgut brome weed. This study was carried out in 1999-2000 season in a greenhouse experiment to test the aggressiveness degree of six varieties of hard wheat (Oum Rabia, Isly, Marzak, Karim, Sebou, and Massa) combined with ripgut brome. Plant density was fixed at 16 plants of wheat or Bromus for pure crop and 8 plants for wheat and 8 for Bromus mixture. The results showed that the numbers of kernels/spikes were higher in the mixture for on pure composition. For the kernel weight, the result was opposite except for Isly and Marzak varieties. Karim and Isly varieties obtained the highest grain yield and were more competitive in mixture composition but Sebou and Massa varieties were less competitive against ripgut brome. Results of ripgut brome productivity and water use efficiency were similar and were used to determine the aggressiveness coefficient of hard wheat varieties against ripgut brome. The reduction of the shoot dry matter of brome was 22 to 56% at flowering. The grain yield of brome was reduced from 57 to 81%.

  13. Epidemiology of Basil Downy Mildew.

    Science.gov (United States)

    Cohen, Yigal; Ben Naim, Yariv; Falach, Lidan; Rubin, Avia E

    2017-06-09

    Basil downy mildew (BDM) caused by the oomycete Peronospora belbahrii is a destructive disease of sweet basil (Ocimum basilicum) worldwide. It originated in Uganda in the 1930s and recently spread to Europe, the Middle East, Americas, and the Far East. Seed transmission may be responsible for its quick global spread. The pathogen attacks leaf blades, producing chlorotic lesions with ample dark asexual spores on the lower leaf surface. Oospores may form in the mesophyll of infected leaves. The asexual spores germinate on a wet leaf surface within 2 h and penetrate into the epidermis within 4 h. Spore germination and infection occur at a wide range of temperatures from 5 to 28.5°C. Infection intensity depends on the length of dew period, leaf temperature, and inoculum dose. The duration of latent period (from infection to sporulation) extends from 5 to 10 days, depending on temperature and light regime. The shortest is 5 days at 25°C under continuous light. Sporulation requires high humidity but not free leaf wetness. Sporulation occurs at 10 to 26°C. At the optimum temperature of 18°C, the process of sporulation requires 7.5 h at relative humidity ≥ 85%, with 3 h for sporophores emergence from stomata and 4.5 h for spore formation. Sporophores can emerge under light or darkness, but spore formation occurs in the dark only. Limited data are available on spore dispersal. Spores dispersed from sporulating plants contaminate healthy plants within 2 h of exposure. Settled spores may survive on leaf surface of healthy plants for prolonged periods, depending on temperature. Seed transmission of the disease occurs in Europe, but not in Israel or the United States. P. belbahrii in Israel also attacks species belonging to Rosemarinus, Nepeta, Agastache, Micromeria, and Salvia but not Plectranthus (coleus). A Peronospora species that infects coleus does not infect sweet basil. Control of BDM includes chemical, physical, and genetic means. The fungicide mefenoxam was

  14. Engineering of Brome mosaic virus for biomedical applications

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    Yildiz, Ibrahim; Tsvetkova, Irina; Wen, Amy M.; Shukla, Sourabh; Masarapu, M. Hema; Dragnea, Bogdan; Steinmetz, Nicole F.

    2016-01-01

    Viral nanoparticles (VNPs) are becoming versatile tools in platform technology development. Their well-defined structures as well as their programmability through chemical and genetic modification allow VNPs to be engineered for potential imaging and therapeutic applications. In this article, we report the application of a variety of bioconjugation chemistries to the plant VNP Brome mosaic virus (BMV). Functional BMV nanoparticles displaying multiple copies of fluorescent dyes, PEG molecules, chemotherapeutic drug moieties, targeting proteins and cell penetrating peptides were formulated. This opens the door for the application of BMV in nanomedicine. PMID:28018580

  15. First record of target-site-resistance of poverty brome (Bromus sterilis to ACCase inhibitors

    Directory of Open Access Journals (Sweden)

    Dicke, Dominik

    2014-02-01

    Full Text Available In 2011 reduced efficacy of grass weed herbicides to poverty brome (Bromus sterilis was observed in oilseed rape on a site in East Hessen. The field was cultivated by using the ploughless tillage system more than 25 years. The site showed high densities of poverty brome (>1000 plants/m² prior to herbicide treatment. Poverty brome seeds were collected in 2012 in the hessian oilseed rape field and from a site in East Westphalia, where poverty brome appeared at low densities (10 plants/m² and was not suspected to resistance. The seeds were sown in to pots and plants cultivated. The plants were treated with two application rates (normal dose, double dose with herbicides of different HRAC-classes. The time of treatment was adjusted to the best expectable treatment/efficiency conditions of the individual herbicides (see chapter 3. Clear differences in efficacy that were caused by herbicide, the origins of poverty brome and the dosages were recorded via visual rating eight weeks after spraying. The herbicides Agil and Focus Ultra were able to control about 90% of the poverty brome plants of the East Westphalia site origin. However, only 20-30% of the Hessian plants could be knocked out by the same herbicides. The ACCase-gene of single powerty brome leaf samples from the hessian site was analyzed after resistance assessment. A molecular genetic analysis on 7 variable positions identified target site resistance: Isoleucine (Ile was replaced by asparagine (Asn at position 2041.

  16. Epidemiology and control of spinach downy mildew in coastal California

    Science.gov (United States)

    The most serious threat to global fresh market spinach production is spinach downy mildew, caused by the obligate biotrophic pathogen, Peronospora effusa. Downy mildew causes yellow chlorotic lesions on spinach leaf tissue, often accompanied by abundant sporulation on the undersides of leaves. Very ...

  17. Evolutionary relationship of alfalfa mosaic virus with cucumber mosaic virus and brome mosaic virus

    OpenAIRE

    Savithri, HS; Murthy, MRN

    1983-01-01

    The amino acid sequences of the non-structural protein (molecular weight 35,000; 3a protein) from three plant viruses - cucumber mosaic, brome mosaic and alfalfa mosaic have been systematically compared using the partial genomic sequences for these three viruses already available. The 3a protein of cucumber mosaic virus has an amino acid sequence homology of 33.7% with the corresponding protein of brome mosaic virus. A similar protein from alfalfa mosaic virus has a homology of 18.2% and 14.2...

  18. Sequencing of the Litchi Downy Blight Pathogen Reveals It Is a Phytophthora Species With Downy Mildew-Like Characteristics.

    Science.gov (United States)

    Ye, Wenwu; Wang, Yang; Shen, Danyu; Li, Delong; Pu, Tianhuizi; Jiang, Zide; Zhang, Zhengguang; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2016-07-01

    On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens.

  19. Comparison of three fungicide spray advisories for lettuce downy mildew

    NARCIS (Netherlands)

    Wu, B.M.; Subbarao, K.V.; Bruggen, van A.H.C.; Koike, S.T.

    2001-01-01

    Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform satisfactoril

  20. An atomic model of brome mosaic virus using direct electron detection and real-space optimization

    OpenAIRE

    Wang, Zhao; Hryc, Corey F.; Bammes, Benjamin; Afonine, Pavel V.; Jakana, Joanita; Chen, Dong-Hua; Liu, Xiangan; Baker, Matthew L.; Kao, Cheng; Ludtke, Steven J; Schmid, Michael F.; Adams, Paul D.; Chiu, Wah

    2014-01-01

    Advances in electron cryo-microscopy have enabled structure determination of macromolecules at near-atomic resolution. However, structure determination, even using de novo methods, remains susceptible to model bias and overfitting. Here we describe a complete workflow for data acquisition, image processing, all-atom modelling and validation of brome mosaic virus, an RNA virus. Data were collected with a direct electron detector in integrating mode and an exposure beyond the traditional radiat...

  1. Quantitative Morphological and Biochemical Studies on Human Downy Hairs using 3-D Quantitative Phase Imaging

    CERN Document Server

    Lee, SangYun; Lee, Yuhyun; Park, Sungjin; Shin, Heejae; Yang, Jongwon; Ko, Kwanhong; Park, HyunJoo; Park, YongKeun

    2015-01-01

    This study presents the morphological and biochemical findings on human downy arm hairs using 3-D quantitative phase imaging techniques. 3-D refractive index tomograms and high-resolution 2-D synthetic aperture images of individual downy arm hairs were measured using a Mach-Zehnder laser interferometric microscopy equipped with a two-axis galvanometer mirror. From the measured quantitative images, the biochemical and morphological parameters of downy hairs were non-invasively quantified including the mean refractive index, volume, cylinder, and effective radius of individual hairs. In addition, the effects of hydrogen peroxide on individual downy hairs were investigated.

  2. Mutants of downy mildew resistance in Lactuca sativa (lettuce).

    Science.gov (United States)

    Okubara, P A; Anderson, P A; Ochoa, O E; Michelmore, R W

    1994-07-01

    As part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to Bremia lactucae, the casual fungus of downy mildew. Using a rapid and reliable screen, we identified 16 distinct mutants of Latuca sativa that have lost activity of one of four different downy mildew resistance genes (Dm). In all mutants, only a single Dm specificity was affected. Genetic analysis indicated that the lesions segregated as single, recessive mutations at the Dm loci. Dm3 was inactivated in nine of the mutants. One of five Dm 1 mutants was selected from a population of untreated seeds and therefore carried a spontaneous mutation. All other Dm1, Dm3, Dm5/8 and Dm7 mutants were derived from gamma- or fast neutron-irradiated seed. In two separate Dm 1 mutants and in each of the eight Dm3 mutants analyzed, at least one closely linked molecular marker was absent. Also, high molecular weight genomic DNA fragments that hybridized to a tightly linked molecular marker in wild type were either missing entirely or were truncated in two of the Dm3 mutants, providing additional evidence that deletions had occurred in these mutants. Absence of mutations at loci epistatic to the Dm genes suggested that such loci were either members of multigene families, were critical for plant survival, or encoded components of duplicated pathways for resistance; alternatively, the genes determining downy mildew resistance might be limited to the Dm loci.

  3. Resistance Against Basil Downy Mildew in Ocimum Species.

    Science.gov (United States)

    Ben-Naim, Yariv; Falach, Lidan; Cohen, Yigal

    2015-06-01

    Downy mildew, caused by the oomycete Peronospora belbahrii, is a devastating disease of sweet basil. In this study, 113 accessions of Ocimum species (83 Plant Introduction entries and 30 commercial entries) were tested for resistance against downy mildew at the seedling stage in growth chambers, and during three seasons, in the field. Most entries belonging to O. basilicum were highly susceptible whereas most entries belonging to O. americanum, O. kilimanadascharicum, O. gratissimum, O. campechianum, or O. tenuiflorum were highly resistant at both the seedling stage and the field. Twenty-seven highly resistant individual plants were each crossed with the susceptible sweet basil 'Peri', and the F1 progeny plants were examined for disease resistance. The F1 plants of two crosses were highly resistant, F1 plants of 24 crosses were moderately resistant, and F1 plants of one cross were susceptible, suggesting full, partial, or no dominance of the resistance gene(s), respectively. These data confirm the feasibility of producing downy mildew-resistant cultivars of sweet basil by crossing with wild Ocimum species.

  4. Genome analyses of the sunflower pathogen Plasmopara halstedii provide insights into effector evolution in downy mildews and Phytophthora

    NARCIS (Netherlands)

    Sharma, Rahul; Xia, Xiaojuan; Cano, Liliana M; Evangelisti, Edouard; Kemen, Eric; Judelson, Howard; Oome, Stan; Sambles, Christine; van den Hoogen, D Johan; Kitner, Miloslav; Klein, Joël; Meijer, Harold J G; Spring, Otmar; Win, Joe; Zipper, Reinhard; Bode, Helge B; Govers, Francine; Kamoun, Sophien; Schornack, Sebastian; Studholme, David J; Van den Ackerveken, Guido; Thines, Marco

    2015-01-01

    BACKGROUND: Downy mildews are the most speciose group of oomycetes and affect crops of great economic importance. So far, there is only a single deeply-sequenced downy mildew genome available, from Hyaloperonospora arabidopsidis. Further genomic resources for downy mildews are required to study thei

  5. Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce

    Science.gov (United States)

    Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in 18th and 19th century, respectively, have high levels of quantitative resistance to downy milde...

  6. Effects of stacked quantitative resistances to downy mildew in lettuce do not simply add up

    NARCIS (Netherlands)

    Boer, den E.; Pelgrom, K.T.B.; Zhang, N.; Visser, R.G.F.; Niks, R.E.; Jeuken, M.J.W.

    2014-01-01

    Key message In a stacking study of eight resistance QTLs in lettuce against downy mildew, only three out of ten double combinations showed an increased resistance effect under field conditions. Abstract Complete race nonspecific resistance to lettuce downy mildew, as observed for the nonhost wild le

  7. Simple Sequence Repeat Markers Useful for Sorghum Downy Mildew (Peronosclerospora sorghi) and Related Species

    Science.gov (United States)

    A recent outbreak of sorghum downy mildew, in Texas, has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically poin...

  8. Mutual Interference between Genomic RNA Replication and Subgenomic mRNA Transcription in Brome Mosaic Virus

    OpenAIRE

    Grdzelishvili, Valery Z.; Garcia-Ruiz, Hernan; Watanabe, Tokiko; Ahlquist, Paul

    2005-01-01

    Replication by many positive-strand RNA viruses includes genomic RNA amplification and subgenomic mRNA (sgRNA) transcription. For brome mosaic virus (BMV), both processes occur in virus-induced, membrane-associated compartments, require BMV replication factors 1a and 2a, and use negative-strand RNA3 as a template for genomic RNA3 and sgRNA syntheses. To begin elucidating their relations, we examined the interaction of RNA3 replication and sgRNA transcription in Saccharomyces cerevisiae expres...

  9. Nocturnal Fanning Suppresses Downy Mildew Epidemics in Sweet Basil.

    Science.gov (United States)

    Cohen, Yigal; Ben-Naim, Yariv

    2016-01-01

    Downy mildew is currently the most serious disease of sweet basil around the world. The oomycete causal agent Peronospora belbahrii requires ≥ 4h free leaf moisture for infection and ≥7.5h of water-saturated atmosphere (relative humidity RH≥95%) at night for sporulation. We show here that continued nocturnal fanning (wind speed of 0.4-1.5 m/s) from 8pm to 8am dramatically suppressed downy mildew development. In three experiments conducted during 2015, percent infected leaves in regular (non-fanned) net-houses reached a mean of 89.9, 94.3 and 96.0% compared to1.2, 1.7 and 0.5% in adjacent fanned net-houses, respectively. Nocturnal fanning reduced the number of hours per night with RH≥95% thus shortened the dew periods below the threshold required for infection or sporulation. In experiments A, B and C, the number of nights with ≥4h of RH≥95% was 28, 10 and 17 in the non-fanned net-houses compared to 5, 0 and 5 in the fanned net-houses, respectively. In the third experiment leaf wetness sensors were installed. Dew formation was strongly suppressed in the fanned net-house as compared to the non-fanned net-house. Healthy potted plants became infected and sporulated a week later if placed one night in the non-fanned house whereas healthy plants placed during that night in the fanned house remained healthy. Infected potted basil plants sporulated heavily after one night of incubation in the non-fanned house whereas almost no sporulation occurred in similar plants incubated that night in the fanned house. The data suggest that nocturnal fanning is highly effective in suppressing downy mildew epidemics in sweet basil. Fanning prevented the within-canopy RH from reaching saturation, reduced dew deposition on the leaves, and hence prevented both infection and sporulation of P. belbahrii.

  10. Host‐induced gene silencing inhibits the biotrophic pathogen causing downy mildew of lettuce

    National Research Council Canada - National Science Library

    Govindarajulu, Manjula; Epstein, Lynn; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-01-01

    .... As a proof‐of‐concept, we generated stable transgenic lettuce plants expressing si RNA s targeting potentially vital genes of Bremia lactucae , a biotrophic oomycete that causes downy mildew, the most important...

  11. Two species of Gelechioidea (Lepidoptera) from Southeast Asia associated with downy rose myrtle, Rhodomyrtus tomentosa (Myrtaceae)

    Science.gov (United States)

    Two species of Gelechioidea (Lepidoptera), Metharmostis multilineata Adamski, n. sp. (Cosmopterigidae), and Idiophantis soreuta Meyrick, 1906 (Gelechiidae), were collected in southeastern Asia for evaluation as potential biocontrol agents against downy rose myrtle, Rhodomyrtus tomentosa (Aiton) Hass...

  12. THE USE OF ENDOPHYTIC FUNGI AS BIOPESTICIDE AGAINST DOWNY MILDEW PERONOSCLEROSPORA SPP. ON MAIZE

    OpenAIRE

    AMIN, NUR; La Daha; Nasruddin, Andi; Junaed, M; Iqbal, Andi

    2013-01-01

    Downy mildew is a major disease of maize caused by the fungus Peronosclerospora spp., widely distributed in all corn production centers in Indonesia. The disease can cause considerable losses; even total losses have been reported occurring on susceptible varieties. The purpose of the research was to determine the effectiveness of some isolates of endophytic fungi for the control of downy mildew on maize. The study consisted of four isolate treatments: Aspergillus spp., Trichoderma spp, Beauv...

  13. Nocturnal Fanning Suppresses Downy Mildew Epidemics in Sweet Basil.

    Directory of Open Access Journals (Sweden)

    Yigal Cohen

    Full Text Available Downy mildew is currently the most serious disease of sweet basil around the world. The oomycete causal agent Peronospora belbahrii requires ≥ 4h free leaf moisture for infection and ≥7.5h of water-saturated atmosphere (relative humidity RH≥95% at night for sporulation. We show here that continued nocturnal fanning (wind speed of 0.4-1.5 m/s from 8pm to 8am dramatically suppressed downy mildew development. In three experiments conducted during 2015, percent infected leaves in regular (non-fanned net-houses reached a mean of 89.9, 94.3 and 96.0% compared to1.2, 1.7 and 0.5% in adjacent fanned net-houses, respectively. Nocturnal fanning reduced the number of hours per night with RH≥95% thus shortened the dew periods below the threshold required for infection or sporulation. In experiments A, B and C, the number of nights with ≥4h of RH≥95% was 28, 10 and 17 in the non-fanned net-houses compared to 5, 0 and 5 in the fanned net-houses, respectively. In the third experiment leaf wetness sensors were installed. Dew formation was strongly suppressed in the fanned net-house as compared to the non-fanned net-house. Healthy potted plants became infected and sporulated a week later if placed one night in the non-fanned house whereas healthy plants placed during that night in the fanned house remained healthy. Infected potted basil plants sporulated heavily after one night of incubation in the non-fanned house whereas almost no sporulation occurred in similar plants incubated that night in the fanned house. The data suggest that nocturnal fanning is highly effective in suppressing downy mildew epidemics in sweet basil. Fanning prevented the within-canopy RH from reaching saturation, reduced dew deposition on the leaves, and hence prevented both infection and sporulation of P. belbahrii.

  14. Inheritance of downy mildew (Plasmopara viticola) and anthracnose (Sphaceloma ampelinum) resistance in grapevines.

    Science.gov (United States)

    Poolsawat, O; Mahanil, S; Laosuwan, P; Wongkaew, S; Tharapreuksapong, A; Reisch, B I; Tantasawat, P A

    2013-12-13

    Downy mildew (Plasmopara viticola) and anthracnose (Sphaceloma ampelinum) are two of the major diseases of most grapevine (Vitis vinifera L.) cultivars grown in Thailand. Therefore, breeding grapevines for improved downy mildew and anthracnose resistance is crucial. Factorial crosses were made between three downy mildew and/or anthracnose resistant lines ('NY88.0517.01', 'NY65.0550.04', and 'NY65.0551.05'; male parents) and two or three susceptible cultivars of V. vinifera ('Black Queen', 'Carolina Black Rose', and/or 'Italia'; female parents). F1 hybrid seedlings were evaluated for downy mildew and anthracnose resistance using a detached/excised leaf assay. For both diseases, the general combining ability (GCA) variance among male parents was significant, while the variance of GCA among females and the specific combining ability (SCA) variance were not significant, indicating the prevalence of additive over non-additive gene actions. The estimated narrow sense heritabilities of downy mildew and anthracnose resistance were 55.6 and 79.2%, respectively, suggesting that downy mildew/anthracnose resistance gene(s) were highly heritable. The 'Carolina Black Rose x NY65.0550.04' cross combination is recommended for future use.

  15. Genetic investigation of the nonhost resistance of wild lettuce, Lactuca saligna, to lettuce downy mildew, Bremia lactucae

    NARCIS (Netherlands)

    Boer, den E.

    2014-01-01

    Abstract Downy mildew (Bremia lactucae) in lettuce (Lactuca sativa) is a devastating foliar disease causing high losses in lettuce cultivation. The wild lettuce and nonhost species, Lactuca saligna, is absolute resistant to downy mildew and cross-fertile with L. sativa, albeit with

  16. Real-time PCR and spore trap-based detection of the downy mildew pathogen, Peronospora effusa

    Science.gov (United States)

    Peronospora effusa is an obligate pathogen and the causal agent of downy mildew on spinach. The pathogen can be dispersed by splashing rain and wind, and may overwinter as oospores. Outbreaks of downy mildew on spinach are common in the cool climate of central coastal California, including the Sal...

  17. Epidemiology and population biology of Pseudoperonospora cubensis: a model system for management of downy mildews.

    Science.gov (United States)

    Ojiambo, Peter S; Gent, David H; Quesada-Ocampo, Lina M; Hausbeck, Mary K; Holmes, Gerald J

    2015-01-01

    The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of outbreaks of cucurbit downy mildew. The dispersal potential of Pseudoperonospora cubensis appears to be limited primarily by sporangia production in source fields and availability of susceptible hosts and less by sporangia survival during transport. Uncertainty remains regarding the role of locally produced inoculum in disease outbreaks, but evidence suggests multiple sources of primary inoculum could be important. Understanding pathogen diversity and population differentiation is a critical aspect of disease management and an active research area. Underpinning advances in our understanding of pathogen biology and disease management has been the research capacity and coordination of stakeholders, scientists, and extension personnel. Concepts and approaches developed in this pathosystem can guide future efforts when responding to incursions of new or reemerging downy mildew pathogens.

  18. Brome mosaic virus Infection of Rice Results in Decreased Accumulation of RNA1.

    Science.gov (United States)

    Kitayama, Masahiko; Hoover, Haley; Middleton, Stefani; Kao, C Cheng

    2015-05-01

    Brome mosaic virus (BMV) (the Russian strain) infects monocot plants and has been studied extensively in barley and wheat. Here, we report BMV can systemically infect rice (Oryza sativa var. japonica), including cultivars in which the genomes have been determined. The BMV capsid protein can be found throughout the inoculated plants. However, infection in rice exhibits delayed symptom expression or no symptoms when compared with wheat (Triticum aestivum). The sequences of BMV RNAs isolated from rice did not reveal any nucleotide changes in RNA1 or RNA2, while RNA3 had only one synonymous nucleotide change from the inoculum sequence. Preparations of purified BMV virions contained RNA1 at a significantly reduced level relative to the other two RNAs. Analysis of BMV RNA replication in rice revealed that minus-strand RNA1 was replicated at a reduced rate when compared with RNA2. Thus, rice appears to either inhibit RNA1 replication or lacks a sufficient amount of a factor needed to support efficient RNA1 replication.

  19. Subcellular localization and rearrangement of endoplasmic reticulum by Brome mosaic virus capsid protein.

    Science.gov (United States)

    Bamunusinghe, Devinka; Seo, Jang-Kyun; Rao, A L N

    2011-03-01

    Genome packaging in the plant-infecting Brome mosaic virus (BMV), a member of the alphavirus-like superfamily, as well as in other positive-strand RNA viruses pathogenic to humans (e.g., poliovirus) and animals (e.g., Flock House virus), is functionally coupled to replication. Although the subcellular localization site of BMV replication has been identified, that of the capsid protein (CP) has remained elusive. In this study, the application of immunofluorescence confocal microscopy to Nicotiana benthamiana leaves expressing replication-derived BMV CP as a green fluorescent protein (GFP) fusion, in conjunction with antibodies to the CP and double-stranded RNA, a presumed marker of RNA replication, revealed that the subcellular localization sites of replication and CP overlap. Our temporal analysis by transmission electron microscopy of ultrastructural modifications induced in BMV-infected N. benthamiana leaves revealed a reticulovesicular network of modified endoplasmic reticulum (ER) incorporating large assemblies of vesicles derived from ER accumulated in the cytoplasm during BMV infection. Additionally, for the first time, we have found by ectopic expression experiments that BMV CP itself has the intrinsic property of modifying ER to induce vesicles similar to those present in BMV infections. The significance of CP-induced vesicles in relation to CP-organized viral functions that are linked to replication-coupled packaging is discussed.

  20. An atomic model of brome mosaic virus using direct electron detection and real-space optimization.

    Science.gov (United States)

    Wang, Zhao; Hryc, Corey F; Bammes, Benjamin; Afonine, Pavel V; Jakana, Joanita; Chen, Dong-Hua; Liu, Xiangan; Baker, Matthew L; Kao, Cheng; Ludtke, Steven J; Schmid, Michael F; Adams, Paul D; Chiu, Wah

    2014-09-04

    Advances in electron cryo-microscopy have enabled structure determination of macromolecules at near-atomic resolution. However, structure determination, even using de novo methods, remains susceptible to model bias and overfitting. Here we describe a complete workflow for data acquisition, image processing, all-atom modelling and validation of brome mosaic virus, an RNA virus. Data were collected with a direct electron detector in integrating mode and an exposure beyond the traditional radiation damage limit. The final density map has a resolution of 3.8 Å as assessed by two independent data sets and maps. We used the map to derive an all-atom model with a newly implemented real-space optimization protocol. The validity of the model was verified by its match with the density map and a previous model from X-ray crystallography, as well as the internal consistency of models from independent maps. This study demonstrates a practical approach to obtain a rigorously validated atomic resolution electron cryo-microscopy structure.

  1. Genetic characterization of quantitative resistance to Bremia lactucae, the causal organism of lettuce downy mildew

    Science.gov (United States)

    Lettuce (Lactuca sativa) is one of the most valuable vegetable crops in the United States. Downy mildew (DM), caused by Bremia lactucae, is the most important foliar disease of lettuce worldwide, which decreases the quality of the marketable portion of the crop. The use of resistant varieties carryi...

  2. Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

    NARCIS (Netherlands)

    Zhang, N.

    2008-01-01

    Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29 Backcro

  3. Genetic dissection of Lactuca saligna nonhost resistance to downy mildew at various lettuce developmental stages

    NARCIS (Netherlands)

    Zhang, N.; Lindhout, P.; Niks, R.E.; Jeuken, M.J.W.

    2009-01-01

    This study used the pathosystem of lettuce (Lactuca spp.) and downy mildew (Bremia lactucae) as a model to investigate the inheritance of nonhost resistance, and focused on the contribution of quantitative trait loci (QTLs) to nonhost resistance at various developmental stages in the lettuce life cy

  4. Epidemiology and population biology of pseudoperonospora cubensis: a model system for management of downy mildews

    Science.gov (United States)

    The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of disease outbreaks. Dispersal potential of th...

  5. Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing

    NARCIS (Netherlands)

    Stassen, J.H.; Seidl, M.F.; Vergeer, P.W.; Nijman, I.J.; Snel, B.; Cuppen, E.; van den Ackerveken, G.

    2012-01-01

    Lettuce downy mildew (Bremia lactucae) is a rapidly adapting oomycete pathogen affecting commercial lettuce cultivation. Oomycetes are known to use a diverse arsenal of secreted proteins (effectors) to manipulate their hosts. Two classes of effector are known to be translocated by the host: the

  6. Downy mildew on coleus (Plectranthus scutellarioides) caused by Peronospora belbahrii sensu lato in Tennessee

    Science.gov (United States)

    Coleus (Plectranthus scutellarioides [syn. = Solenostemon scutellarioides]) is a popular ornamental plant in the mint family (Lamiaceae), prized for its colorful and showy foliage. In August 2015, disease symptoms typical of downy mildew were observed at two sites in Nashville, Tennessee: (i) at the...

  7. Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing

    NARCIS (Netherlands)

    Stassen, J.H.; Seidl, M.F.; Vergeer, P.W.; Nijman, I.J.; Snel, B.; Cuppen, E.; van den Ackerveken, G.

    2012-01-01

    Lettuce downy mildew (Bremia lactucae) is a rapidly adapting oomycete pathogen affecting commercial lettuce cultivation. Oomycetes are known to use a diverse arsenal of secreted proteins (effectors) to manipulate their hosts. Two classes of effector are known to be translocated by the host: the RXLR

  8. Identification of breeding signatures in grapevine hybrids, donors of resistances against downy and powdery mildew

    NARCIS (Netherlands)

    Vezzulli, S.; Peressotti, E.; Banchi, E.; Dolzani, C.; Micheli, S.; Stefanini, M.; Salamini, F.; Velasco, R.; Riaz, S.; Walker, M.A.; Reisch, B.I.; De Weg, Van W.E.; Bink, M.C.

    2015-01-01

    Grapevine (Vitis vinifera L.) is one of the most valuable crops in the world, but has been often plagued by encountering new parasites that still represent a major constraint, such as downy (DM) and powdery (PM) mildew. Nowadays, growers are still obliged to recur to a massive use of pesticides t

  9. Identification of breeding signatures in grapevine hybrids, donors of resistances against downy and powdery mildew

    NARCIS (Netherlands)

    Vezzulli, S.; Peressotti, E.; Banchi, E.; Dolzani, C.; Micheli, S.; Stefanini, M.; Salamini, F.; Velasco, R.; Riaz, S.; Walker, M.A.; Reisch, B.I.; De Weg, Van W.E.; Bink, M.C.

    2015-01-01

    Grapevine (Vitis vinifera L.) is one of the most valuable crops in the world, but has been often plagued by encountering new parasites that still represent a major constraint, such as downy (DM) and powdery (PM) mildew. Nowadays, growers are still obliged to recur to a massive use of pesticides

  10. Assessing the vulnerability of sorghum converted lines to anthracnose and downy mildew infection

    Science.gov (United States)

    A total of 59 converted sorghum lines and six checks were evaluated for resistance to two foliar fungal diseases, anthracnose and downy mildew (SDM) in 2008 and 2009 growing seasons at the Texas A&M AgriLife Research Farm, College Station, Texas. In 2008, 23 lines exhibited resistance (35%), 29 sus...

  11. Association of RGA-SSCP markers with resistance to downy mildew and anthracnose in grapevines.

    Science.gov (United States)

    Tantasawat, P A; Poolsawat, O; Prajongjai, T; Chaowiset, W; Tharapreuksapong, A

    2012-07-02

    Downy mildew (Plasmopara viticola) and anthracnose (Sphaceloma ampelinum) are two major diseases that severely affect most grapevine (Vitis vinifera) cultivars grown commercially in Thailand. Progress of conventional breeding programs of grapevine for improved resistance to these diseases can be speeded up by selection of molecular markers associated with resistance traits. We evaluated the association between 13 resistance gene analog (RGA)-single-strand conformation polymorphism (SSCP) markers with resistance to downy mildew and anthracnose in 71 segregating progenies of seven cross combinations between susceptible cultivars and resistant lines. F(1) hybrids from each cross were assessed for resistance to downy mildew and anthracnose (isolates Nk4-1 and Rc2-1) under laboratory conditions. Association of resistance traits with RGA-SSCP markers was evaluated using simple linear regression analysis. Three RGA-SSCP markers were found to be significantly correlated with anthracnose resistance, whereas significant correlation with downy mildew resistance was observed for only one RGA-SSCP marker. These results demonstrate the usefulness of RGA-SSCP markers. Four candidate markers with significant associations to resistance to these two major diseases of grapevine were identified. However, these putative associations between markers and resistance need to be verified with larger segregating populations before they can be used for marker-assisted selection.

  12. [Cartography and geographical spread of the adventitious species of brome (Bromus spp.) among cereals in the Sais area of Morocco].

    Science.gov (United States)

    Hamal, A; Benbella, M; Rzozi, S B; Bouhache, M; Msatef, Y

    2001-01-01

    Bromus spp is causing serious problems in wheat in the Sais area. However, the damage of this weed varies from one region to another according to the agro-climatic conditions and crop systems. The characterization of the infestation level in each situation is a prerequisite to develop a control strategy adapted to each environment. This study was undertaken in order to determine the infestation level and geographical spread of the weedy brome (Bromus spp) on wheat in Sais following crop systems and pedo-climatic conditions. The results obtained during two consecutive years (1998-99 and 1999-2000) revealed that ripgut brome (Bromus rigidus Roth.) was the most dominant species in wheat fields in the surveyed regions, followed by B. rubens L., B. sterilis L., B. madritensis L. and B. mollus L. Among, 18 regions and 100 infested wheat fields, 16.67% of fields were slightly infested (Plant density of Bromus (Dbr 400 plants/m2). The maximum relative frequency was obtained with Bromus rigidus (47.15%) and the coverage was 40.43%. But, for B.rubens, B. madritensis and B. sterilis, the relative frequencies were respectively 31.42; 26 and 15% and their coverages were respectively 28.9, 20.4 and 12.5%.

  13. Macro- and microscopic leaf characteristics of six grapevine genotypes (Vitis spp.) with different susceptibilities to grapevine downy mildew

    OpenAIRE

    Boso Alonso, Susana; Alonso-Villaverde Iglesias, Virginia; Santiago Blanco, José Luis; Gago Montaña, Pilar; Dürrenberger, M.; Düggelin, M.; Kassemeyer, H. H.; Martínez Rodríguez, María del Carmen

    2010-01-01

    This work reports the leaf morphology of six grapevine genotypes, five belonging to Vitis vinifera and one to Vitis riparia. Earlier studies on these genotypes showed different levels of susceptibility to grapevine downy mildew (Plasmopara viticola). The aim of this work was to detect differences between the leaf morphology of these cultivars at the macro- and microscopic levels, and to characterize morphological traits which could be associated with susceptibility and resistance to downy ...

  14. Correlations between the contents of phytic acid and inorganic phosphorous and downy mildew resistance of corn inbred lines

    OpenAIRE

    Pantipa Na Chiangmai*; Phrutiya Nilprapruck; Warapon Bunkoed; Phakatip Yodmingkhwan; Chokechai Aekatasanawan; Mana Kanjanamaneesathian

    2015-01-01

    Seeds of corn inbred lines collected at the National Corn and Sorghum Research Center (NCSRC), Kasetsart University, were analyzed to determine the contents of phytic acid (PA) and inorganic phosphorous (InP). These 28 and 29 inbred lines were cultivated at the NCSRC (in the 2008 late rainy season and 2009 early rainy season) to evaluate their resistance to corn downy mildew caused by Peronosclerospora sorghi. Results showed that the values of the PA, InP contents and downy mildew...

  15. Effects of Heat Shock on Photosynthetic Properties, Antioxidant Enzyme Activity, and Downy Mildew of Cucumber (Cucumis sativus L.).

    Science.gov (United States)

    Ding, Xiaotao; Jiang, Yuping; Hao, Ting; Jin, Haijun; Zhang, Hongmei; He, Lizhong; Zhou, Qiang; Huang, Danfeng; Hui, Dafeng; Yu, Jizhu

    2016-01-01

    Heat shock is considered an abiotic stress for plant growth, but the effects of heat shock on physiological responses of cucumber plant leaves with and without downy mildew disease are still not clear. In this study, cucumber seedlings were exposed to heat shock in greenhouses, and the responses of photosynthetic properties, carbohydrate metabolism, antioxidant enzyme activity, osmolytes, and disease severity index of leaves with or without the downy mildew disease were measured. Results showed that heat shock significantly decreased the net photosynthetic rate, actual photochemical efficiency, photochemical quenching coefficient, and starch content. Heat shock caused an increase in the stomatal conductance, transpiration rate, antioxidant enzyme activities, total soluble sugar content, sucrose content, soluble protein content and proline content for both healthy leaves and downy mildew infected leaves. These results demonstrate that heat shock activated the transpiration pathway to protect the photosystem from damage due to excess energy in cucumber leaves. Potential resistance mechanisms of plants exposed to heat stress may involve higher osmotic regulation capacity related to an increase of total accumulations of soluble sugar, proline and soluble protein, as well as higher antioxidant enzymes activity in stressed leaves. Heat shock reduced downy mildew disease severity index by more than 50%, and clearly alleviated downy mildew development in the greenhouses. These findings indicate that cucumber may have a complex physiological change to resist short-term heat shock, and suppress the development of the downy mildew disease.

  16. Effects of Heat Shock on Photosynthetic Properties, Antioxidant Enzyme Activity, and Downy Mildew of Cucumber (Cucumis sativus L..

    Directory of Open Access Journals (Sweden)

    Xiaotao Ding

    Full Text Available Heat shock is considered an abiotic stress for plant growth, but the effects of heat shock on physiological responses of cucumber plant leaves with and without downy mildew disease are still not clear. In this study, cucumber seedlings were exposed to heat shock in greenhouses, and the responses of photosynthetic properties, carbohydrate metabolism, antioxidant enzyme activity, osmolytes, and disease severity index of leaves with or without the downy mildew disease were measured. Results showed that heat shock significantly decreased the net photosynthetic rate, actual photochemical efficiency, photochemical quenching coefficient, and starch content. Heat shock caused an increase in the stomatal conductance, transpiration rate, antioxidant enzyme activities, total soluble sugar content, sucrose content, soluble protein content and proline content for both healthy leaves and downy mildew infected leaves. These results demonstrate that heat shock activated the transpiration pathway to protect the photosystem from damage due to excess energy in cucumber leaves. Potential resistance mechanisms of plants exposed to heat stress may involve higher osmotic regulation capacity related to an increase of total accumulations of soluble sugar, proline and soluble protein, as well as higher antioxidant enzymes activity in stressed leaves. Heat shock reduced downy mildew disease severity index by more than 50%, and clearly alleviated downy mildew development in the greenhouses. These findings indicate that cucumber may have a complex physiological change to resist short-term heat shock, and suppress the development of the downy mildew disease.

  17. Isolation and evaluation of proteolytic actinomycete isolates as novel inducers of pearl millet downy mildew disease protection

    Science.gov (United States)

    Jogaiah, Sudisha; Kurjogi, Mahantesh; Govind, Sharathchandra Ramasandra; Huntrike, Shekar Shetty; Basappa, Vedamurthy Ankala; Tran, Lam-Son Phan

    2016-01-01

    Native endophytic actinomycetes isolated from pearl millet roots were examined for their efficacy to protect pearl millet against downy mildew. Nineteen of 39 isolates were found to be proteolytic, of which 7 strains could directly suppress the sporangium formation of Sclerospora graminicola, the pearl millet downy mildew pathogen. Thus, mycelial suspensions containing either spores or cell-free extract of these 7 isolates were used for seed-coating and -soaking treatments to test for their induction of downy mildew resistance. Results indicated that seed-coating overall provided better protection to downy mildew than seed-soaking. In both treatments, the tested isolates demonstrated differential abilities in downy mildew disease protection, with Streptomyces griseus SJ_UOM-07-09 and Streptosporangium roseum SJ_UOM-18-09 showing the highest protection rates. Additionally, the levels of disease protection conferred by the actinomycetes were just slightly lower than that of the systemic fungicide Apron, suggesting their effectiveness. Further studies revealed that the more rapid root colonization by SJ_UOM-18-09 resulted in faster and higher induced resistance in comparison with SJ_UOM-07-09 under greenhouse conditions, indicating that SJ_UOM-18-09 was superior than SJ_UOM-07-09 in inducing resistance. Results from this study provide comprehensive information on biocontrol functions of SJ_UOM- 18-09 with great potential to control downy mildew disease in pearl millet. PMID:27499196

  18. Fungi colonising the above-ground parts of fodder galega (Galega orientalis Lam. cultivated in pure sowing and mixed with smooth brome-grass (Bromus inermis Leyss.

    Directory of Open Access Journals (Sweden)

    Bożena Cwalina-Ambroziak

    2012-12-01

    Full Text Available Field experiments were carried out in 1999-2001 in the experimental field in Knopin near Dobre Miasto to determine the intensity of fodder galega diseases cultivated in pure sowing and mixed with smooth brome-grass (the Hillstrand and Auld' s modified scale, 1982. The fungi colonising the phyllosphere of fodder galega were analysed in a laboratory (Chruoeciak , 1974. The following symptoms were observed in fodder galega: ascochyta blight (Ascochyta sp., gray mould (Botrytis cinerea and plant wilting (Fusarium oxysporum.. The climatic conditions had an effect on the development of diseases. The greatest intensity of gray mould (Ii = 24.3% and plant wilting (17.9% of plants with the disease symptoms were observed in 2001. Ascochyta blight occurred with the lowest intensity and the highest infection index in 1999 in the cultivation of fodder galega mixed with smooth brome-grass was only 12.1%. The type of cultivation also modified fodder galega disease intensity. Gray mould and plant wilting developed better in pure sowing than in mixed sowing with smooth brome-grass. Throughout the entire experiment period the average infection index was 22.8% and 15.9% of plants with the wilt symptoms. Ascochyta blight found better conditions for development in plants cultivated in a mix with smooth brome-grass (average infection index - 10.0%. The fodder galega phyllosphere provided 4149 fungal isolates represented by 17 species and yeast-like fungi. Yeast-like fungi dominated (75.6% of the total isolates. The following species were less numerous: Botrytis cinerea, Humicola brevis, Acremonium strictum and Cladosporium cladosporioides. From the leaves of fodder galega cultivated in pure sowing, 3.8% more fungi were obtained than from the leaves of plants cultivated with a mix of smooth brome-grass, including more frequently isolated pathogenic fungi representing the genera of Fusarium and the species of Botrytis cinerea.

  19. Rapid Staining Method to Detect and Identify Downy Mildew (Peronospora belbahrii in Basil

    Directory of Open Access Journals (Sweden)

    Adolfina R. Koroch

    2013-07-01

    Full Text Available Premise of the study: Demand for fresh-market sweet basil continues to increase, but in 2009 a new pathogen emerged, threatening commercial field/greenhouse production and leading to high crop losses. This study describes a simple and effective staining method for rapid microscopic detection of basil downy mildew (Peronospora belbahrii from leaves of basil (Ocimum basilicum. Methods and Results: Fresh leaf sections infected with P. belbahrii were placed on a microscope slide, cleared with Visikol™, and stained with iodine solution followed by one drop of 70% sulfuric acid. Cell walls of the pathogen were stained with a distinct coloration, providing a high-contrast image between the pathogen and plant. Conclusions: This new staining method can be used successfully to identify downy mildew in basil, which then can significantly reduce its spread if identified early, coupled with mitigation strategies. This technique can facilitate the control of the disease, without expensive and specialized equipment.

  20. Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

    OpenAIRE

    Zhang, N.

    2008-01-01

    Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29 Backcross Inbred Lines (BILs) representing in total 96% of the L. saligna genome, 15 introgressions were identified to contribute to this resistance at one to four tested lettuce developmental stages and ...

  1. rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew

    Institute of Scientific and Technical Information of China (English)

    Na WANG; Yajun MA; Cuiyun YANG; Guanghui DAI; Zhezhi WANG

    2008-01-01

    To determine the pathogens of cucumber downy mildew and cucumber powdery mildew by molecular marker,we amplified and sequenced the rDNA-ITS region of the pathogens of cucumber downy mildew and cucumber powdery mildew collected from the Shanghai region.The intra-/interspecific sequence difference was analyzed by rDNA-ITS sequence.The results show that the length of rDNA-ITS1 and rDNA-ITS2 of cucumber downy mildew's pathogen was 141 bp and 406 bp,respectively,with GC contents of 41.13% in ITS1 and 46.8% (Minhang and Jinshan District,sml and sm2) or 46.55% (Pudong District,sm3) in ITS2.The rDNA-ITS sequence was intraspecific conservation.The interspecific difference was related with their kin relationship.The pathogen of cucumber downy mildew was identified as Pseudoperonospora cubensis by molecular marker.The length of rDNA-ITS1 and rDNA-ITS2 of cucumber powdery mildew's pathogen was 136 bp and 89 bp,respectively,with GC contents being 59.56% and 66.29%,and rDNA-ITS sequence being highly conservative in this study that was the same as Sphaerotheca cucurbitae.But the sequence difference between the strains in the Shanghai region in this study with S.fuliginea was 4.5%,which was identified by morphology.It is suggested that the pathogen of cucumber powdery mildew should be further clarified and determined.

  2. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil.

    Directory of Open Access Journals (Sweden)

    Yigal Cohen

    Full Text Available The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a 'green' method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45 °C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22 °C reaching 40-58 °C (greenhouse effect. Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants.

  3. Spatial analysis of lettuce downy mildew using geostatistics and geographic information systems.

    Science.gov (United States)

    Wu, B M; van Bruggen, A H; Subbarao, K V; Pennings, G G

    2001-02-01

    ABSTRACT The epidemiology of lettuce downy mildew has been investigated extensively in coastal California. However, the spatial patterns of the disease and the distance that Bremia lactucae spores can be transported have not been determined. During 1995 to 1998, we conducted several field- and valley-scale surveys to determine spatial patterns of this disease in the Salinas valley. Geostatistical analyses of the survey data at both scales showed that the influence range of downy mildew incidence at one location on incidence at other locations was between 80 and 3,000 m. A linear relationship was detected between semivariance and lag distance at the field scale, although no single statistical model could fit the semi-variograms at the valley scale. Spatial interpolation by the inverse distance weighting method with a power of 2 resulted in plausible estimates of incidence throughout the valley. Cluster analysis in geographic information systems on the interpolated disease incidence from different dates demonstrated that the Salinas valley could be divided into two areas, north and south of Salinas City, with high and low disease pressure, respectively. Seasonal and spatial trends along the valley suggested that the distinction between the downy mildew conducive and nonconducive areas might be determined by environmental factors.

  4. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil.

    Science.gov (United States)

    Cohen, Yigal; Rubin, Avia E

    2015-01-01

    The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a 'green' method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45 °C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22 °C reaching 40-58 °C (greenhouse effect). Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants.

  5. RESEARCHES REGARDING THE EFFECT OF SOME BIOLOGICALLY ACTIVE PRODUCTS UPON THE GERMINATION CAPACITIES OF SMOOTH BROME SEEDS

    Directory of Open Access Journals (Sweden)

    I. PET

    2013-12-01

    Full Text Available The carrying out of uniform forage crops represents an important technological loop for all agricultural species. The uniformity of these crops is caused especially by seed germination capacity, respectively by plant emergence capacity, depending upon the climatic and technological conditions. With regards to the researches carried out in this direction, we present here the influence exerted by some biologically-active products, used through extra-root application during plant vegetation period, upon seeds submitted to germination. The observations performed on smooth brome seeds have led to the conclusion that the per cent of germinated seeds ranges from 82%, in the untreated control variant, to 87.67% in the variant treated with the product Stimupro.

  6. Natural succession impeded by smooth brome (Bromus inermis) and intermediate wheatgrass (Agropyron intermedium) in an abandoned agricultural field

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, J.K. [PTI Environmental Services, Boulder, CO (United States)

    1997-11-01

    In 1975, an abandoned agricultural field at Rocky Flats Environmental Technology Site (Site) that had been cultivated for more than 38 years, was seeded with smooth brome (Bromus inermis) and intermediate wheatgrass (Agropyron intermedium). Although these species are commonly planted in reclamation and roadside seed mixtures, few studies have documented their impact on the re-establishment of native plant communities. In 1994, species richness, cover, and biomass were sampled in the agricultural field and compared to the surrounding mixed-grass prairie at the Site. The agricultural field contained only 61 plant species (62% native), compared to 143 species (81% native) in the surrounding mixed-grass prairie. Community similarity based on species presence/absence was 0.47 (Sorensen coefficient of similarity). Basal vegetative cover was 11.2% in the agricultural field and 29.1% in the mixed-grass prairie. Smooth brome and intermediate wheatgrass accounted for 93% of the relative foliar cover and 96% of the biomass in the agricultural field. The aggressive nature of these two planted species has impeded the natural succession of the agricultural field to a more native prairie community. Studies of natural succession on abandoned fields and roads in northeastern Colorado have indicated that if left alone, fields would return to their native climax state in approximately 50 years and would be approaching their native state after 20--25 years. Based on the results of this study, this agricultural field may take more than 100 years to return to a native mixed-grass prairie state and it may never achieve a native state without human intervention.

  7. Specific In Planta Recognition of Two GKLR Proteins of the Downy Mildew Bremia lactucae Revealed in a Large Effector Screen in Lettuce

    NARCIS (Netherlands)

    Stassen, J.H.M.; Boer, den E.; Vergeer, P.W.J.; Andel, A.; Ellendorff, U.; Pelgrom, K.T.B.; Pel, M.; Schut, J.; Zonneveld, O.; Jeuken, M.J.W.; Ackerveken, van den G.

    2013-01-01

    Breeding lettuce (Lactuca sativa) for resistance to the downy mildew pathogen Bremia lactucae is mainly achieved by introgression of dominant downy mildew resistance (Dm) genes. New Bremia races quickly render Dm genes ineffective, possibly by mutation of recognized host-translocated effectors or by

  8. Genetics and mapping of a novel downy mildew resistance gene, Pl18, introgressed from wild Helianthus argophyllus into cultivated sunflower (Helianthus annuus L.)

    Science.gov (United States)

    Sunflower downy mildew is considered to be the most destructive foliar disease that has spread to every major sunflower-growing country of the world, except Australia. A new dominant downy mildew resistance gene (Pl18) transferred from wild Helianthus argophyllus (PI 494573) into cultivated sunflowe...

  9. Analysis of microsatellites from the transcriptome of downy mildew pathogens and their application for characterization of Pseudoperonospora populations

    Directory of Open Access Journals (Sweden)

    Emma C. Wallace

    2017-05-01

    Full Text Available Downy mildew pathogens affect several economically important crops worldwide but, due to their obligate nature, few genetic resources are available for genomic and population analyses. Draft genomes for emergent downy mildew pathogens such as the oomycete Pseudoperonospora cubensis, causal agent of cucurbit downy mildew, have been published and can be used to perform comparative genomic analysis and develop tools such as microsatellites to characterize pathogen population structure. We used bioinformatics to identify 2,738 microsatellites in the P. cubensis predicted transcriptome and evaluate them for transferability to the hop downy mildew pathogen, Pseudoperonospora humuli, since no draft genome is available for this species. We also compared the microsatellite repertoire of P. cubensis to that of the model organism Hyaloperonospora arabidopsidis, which causes downy mildew in Arabidopsis. Although trends in frequency of motif-type were similar, the percentage of SSRs identified from P. cubensis transcripts differed significantly from H. arabidopsidis. The majority of a subset of microsatellites selected for laboratory validation (92% produced a product in P. cubensis isolates, and 83 microsatellites demonstrated transferability to P. humuli. Eleven microsatellites were found to be polymorphic and consistently amplified in P. cubensis isolates. Analysis of Pseudoperonospora isolates from diverse hosts and locations revealed higher diversity in P. cubensis compared to P. humuli isolates. These microsatellites will be useful in efforts to better understand relationships within Pseudoperonospora species and P. cubensis on a population level.

  10. Correlations between the contents of phytic acid and inorganic phosphorous and downy mildew resistance of corn inbred lines

    Directory of Open Access Journals (Sweden)

    Pantipa Na Chiangmai

    2015-10-01

    Full Text Available Seeds of corn inbred lines collected at the National Corn and Sorghum Research Center (NCSRC, Kasetsart University, were analyzed to determine the contents of phytic acid (PA and inorganic phosphorous (InP. These 28 and 29 inbred lines were cultivated at the NCSRC (in the 2008 late rainy season and 2009 early rainy season to evaluate their resistance to corn downy mildew caused by Peronosclerospora sorghi. Results showed that the values of the PA, InP contents and downy mildew infection were statistically different among these inbred lines in both seasons. However, there were no correlations between the contents of either PA or InP and downy mildew infection.

  11. Simple sequence repeat markers useful for sorghum downy mildew (Peronosclerospora sorghi and related species

    Directory of Open Access Journals (Sweden)

    Odvody Gary N

    2008-11-01

    Full Text Available Abstract Background A recent outbreak of sorghum downy mildew in Texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and species, and to study the population structure within these obligate oomycetes. Here we present the initial results from the use of a biotin capture method to discover, clone and develop PCR primers that permit the use of simple sequence repeats (microsatellites to detect differences at the DNA level. Results Among the 55 primers pairs designed from clones from pathotype 3 of P. sorghi, 36 flanked microsatellite loci containing simple repeats, including 28 (55% with dinucleotide repeats and 6 (11% with trinucleotide repeats. A total of 22 microsatellites with CA/AC or GT/TG repeats were the most abundant (40% and GA/AG or CT/TC types contribute 15% in our collection. When used to amplify DNA from 19 isolates from P. sorghi, as well as from 5 related species that cause downy mildew on other hosts, the number of different bands detected for each SSR primer pair using a LI-COR- DNA Analyzer ranged from two to eight. Successful cross-amplification for 12 primer pairs studied in detail using DNA from downy mildews that attack maize (P. maydis & P. philippinensis, sugar cane (P. sacchari, pearl millet (Sclerospora graminicola and rose (Peronospora sparsa indicate that the flanking regions are conserved in all these species. A total of 15 SSR amplicons unique to P. philippinensis (one of the potential threats to US maize production were detected, and these have potential for development of diagnostic tests. A total of 260 alleles were obtained using 54 microsatellites primer combinations, with an average of 4.8 polymorphic markers per SSR across 34

  12. Effect of climate change on infection of grapevine by downy and powdery mildew under controlled environment.

    Science.gov (United States)

    Pugliese, M; Gullino, M L; Garibaldi, A

    2011-01-01

    Plant responses to elevated CO2 and temperature have been much studied in recent years, but effects of climate change on pathological responses are largerly unknown. The pathosystems grapevine (Vitis vinifera) - downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necatrix) were chosen as models to assess the potential impact of increased CO2 and temperature on disease incidence and severity under controlled environment. Grapevine potted plants were grown in phytotrons under 4 different simulated climatic conditions: (1) standard temperature (ranging from 18 degrees to 22 degrees C) and standard CO2 concentration (450 ppm); (2) standard temperature and elevated CO2 concentration (800 ppm); (3) elevated temperature (ranging from 22 degrees to 26 degrees C, 4 degrees C higher than standard) and standard CO2 concentration; (4) elevated temperature and CO2 concentration. Each plant was inoculated with a spore suspension containing 5x10(5) cfu/ml. Disease index and physiological parameters (chlorophyll content, fluorescence, assimilation rate) were assessed. Results showed an increase of the chlorophyll content with higher temperatures and CO2 concentration, to which consequently corresponded an higher fluorescence index. Disease incidence of downy mildew increased when both CO2 and temperatures were higher, while an increase in CO2 did not influenced powdery mildew incidence, probably due to the increased photosynthetic activity of plants under such conditions. Considering that the rising concentrations of CO2 and other greenhouse gases will lead to an increase in global temperature and longer seasons, we can assume that this will allow more time for pathogens evolution and could increase pathogen survival, indirectly affecting downy and powdery mildews of grapevine.

  13. Classification of images of wheat, ryegrass and brome grass species at early growth stages using principal component analysis

    Directory of Open Access Journals (Sweden)

    Golzarian Mahmood R

    2011-09-01

    Full Text Available Abstract Wheat is one of the most important crops in Australia, and the identification of young plants is an important step towards developing an automated system for monitoring crop establishment and also for differentiating crop from weeds. In this paper, a framework to differentiate early narrow-leaf wheat from two common weeds from their digital images is developed. A combination of colour, texture and shape features is used. These features are reduced to three descriptors using Principal Component Analysis. The three components provide an effective and significant means for distinguishing the three grasses. Further analysis enables threshold levels to be set for the discrimination of the plant species. The PCA model was evaluated on an independent data set of plants and the results show accuracy of 88% and 85% in the differentiation of ryegrass and brome grass from wheat, respectively. The outcomes of this study can be integrated into new knowledge in developing computer vision systems used in automated weed management.

  14. The plant host can affect the encapsidation of brome mosaic virus (BMV) RNA: BMV virions are surprisingly heterogeneous.

    Science.gov (United States)

    Ni, Peng; Vaughan, Robert C; Tragesser, Brady; Hoover, Haley; Kao, C Cheng

    2014-03-01

    Brome mosaic virus (BMV) packages its genomic and subgenomic RNAs into three separate viral particles. BMV purified from barley, wheat, and tobacco have distinct relative abundances of the encapsidated RNAs. We seek to identify the basis for the host-dependent differences in viral RNA encapsidation. Sequencing of the viral RNAs revealed recombination events in the 3' untranslated region of RNA1 of BMV purified from barley and wheat, but not from tobacco. However, the relative amounts of the BMV RNAs that accumulated in barley and wheat are similar and RNA accumulation is not sufficient to account for the difference in RNA encapsidation. Virions purified from barley and wheat were found to differ in their isoelectric points, resistance to proteolysis, and contacts between the capsid residues and the RNA. Mass spectrometric analyses revealed that virions from the three hosts had different post-translational modifications that should impact the physiochemical properties of the virions. Another major source of variation in RNA encapsidation was due to the purification of BMV particles to homogeneity. Highly enriched BMV present in lysates had a surprising range of sizes, buoyant densities, and distinct relative amounts of encapsidated RNAs. These results show that the encapsidated BMV RNAs reflect a combination of host effects on the physiochemical properties of the viral capsids and the enrichment of a subset of virions. The previously unexpected heterogeneity in BMV should influence the timing of the infection and also the host innate immune responses.

  15. The coat protein leads the way: an update on basic and applied studies with the Brome mosaic virus coat protein.

    Science.gov (United States)

    Kao, C Cheng; Ni, Peng; Hema, Masarapu; Huang, Xinlei; Dragnea, Bogdan

    2011-05-01

    The Brome mosaic virus (BMV) coat protein (CP) accompanies the three BMV genomic RNAs and the subgenomic RNA into and out of cells in an infection cycle. In addition to serving as a protective shell for all of the BMV RNAs, CP plays regulatory roles during the infection process that are mediated through specific binding of RNA elements in the BMV genome. One regulatory RNA element is the B box present in the 5' untranslated region (UTR) of BMV RNA1 and RNA2 that play important roles in the formation of the BMV replication factory, as well as the regulation of translation. A second element is within the tRNA-like 3' UTR of all BMV RNAs that is required for efficient RNA replication. The BMV CP can also encapsidate ligand-coated metal nanoparticles to form virus-like particles (VLPs). This update summarizes the interaction between the BMV CP and RNAs that can regulate RNA synthesis, translation and RNA encapsidation, as well as the formation of VLPs.

  16. Inhibition of brome mosaic virus (BMV) amplification in protoplasts from transgenic tobacco plants expressing replicable BMV RNAs.

    Science.gov (United States)

    Kaido, M; Mori, M; Mise, K; Okuno, T; Furusawa, I

    1995-11-01

    Transgenic tobacco plants (V123 plants) expressing a set of full-length brome mosaic virus (BMV) genomic RNAs from the cauliflower mosaic virus 35S promoter were produced. The accumulation level of BMV RNAs in V123 plant cells was approximately 1% of that in nontransgenic tobacco protoplasts inoculated with BMV RNAs. The level of BMV RNA in V123 protoplasts did not increase after inoculating the protoplasts with BMV RNAs, whereas V123 protoplasts supported the accumulation of cucumber mosaic virus (CMV) RNAs to a level similar to that in non-transgenic tobacco protoplasts after inoculation with CMV RNA. Such BMV-specific resistance was also observed in protoplasts from V12 plants expressing full-length BMV RNA1 and RNA2, both of which are required and sufficient for BMV RNA replication. On the other hand, protoplasts from M12 plants, expressing truncated BMV RNA1 and RNA2 in which the 3' 200 nucleotides required for BMV RNA replication were deleted, exhibited weaker resistance to infection with BMV RNA than V12 protoplasts, although the accumulation level of truncated BMV RNA1 and RNA2 in M12 protoplasts was higher than that of BMV RNA1 and RNA2 in V12 protoplasts. These results suggest that expression of BMV RNA replicons is involved in the induction of resistance, rather than high-level accumulation of BMV RNAs and/or their encoded proteins.

  17. Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus.

    Science.gov (United States)

    Zhu, Lin; Zhu, Jian; Liu, Zhixue; Wang, Zhengyi; Zhou, Cheng; Wang, Hong

    2017-09-26

    Magnaportheoryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M.oryzae-derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M.oryzae was examined by targeting three predicted pathogenicity genes, MoABC1,MoMAC1 and MoPMK1. Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M.oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.

  18. RESEARCHES CONCERNING THE ECONOMIC EFFICIENCY ACHIEVED SUCCESSIVE TO THE APPLICATION OF BIOLOGICALLY-ACTIVE PRODUCTS IN SMOOTH BROME CROP

    Directory of Open Access Journals (Sweden)

    ELENA PEł

    2013-12-01

    Full Text Available Within any branch of material production, the supervision of the economic effects caused by the applied technologies is an essential requirement. Not only related to the productive activity, but also related to scientific research, designing and other fields of activity, the final goal is represented by the achievement of immediate or far off economic effects. The introduction and generalization into production of the newest technologies of forage production must rely upon calculations of economic efficiency, too. The objective of these calculations is to offer to any producer the possibility to choose among the optimal technologic variants, with great productions per surface unit, of high quality and low costs. The calculations of economic efficiency were carried out during the three years of experimentation. The economic efficiency obtained after the application of biostimulants in smooth brome during the first year of production is expressed through the achievement of a profit per surface unit of 75.85 – 127.00 €/ha. Successive to the calculations of economic efficiency, during the second year of production, the profit per surface unit recorded values between 79.10 – 153.10 €/ha depending upon the applied biostimulant, and during the third year of production the profit obtained per surface unit was 211.05 – 270.70 €/ha.

  19. Using next-generation sequencing to develop molecular diagnostics for Pseudoperonospora cubensis, the cucurbit downy mildew pathogen

    Science.gov (United States)

    Advances in Next Generation Sequencing (NGS) allow for rapid development of genomics resources needed to generate molecular diagnostics assays for infectious agents. NGS approaches are particularly helpful for organisms that cannot be cultured, such as the downy mildew pathogens, a group of biotrop...

  20. Resistance to downy mildew in lettuce ‘La Brillante’ is conferred by dm50 gene and multiple QTL

    Science.gov (United States)

    Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar La Brillante has a high level of field resistance to the disease in California. Testing of a mapping popu...

  1. Elicitation of resistance and associated defense responses in Trichoderma hamatum induced protection against pearl millet downy mildew pathogen

    Science.gov (United States)

    Siddaiah, Chandra Nayaka; Satyanarayana, Niranjan Raj; Mudili, Venkataramana; Kumar Gupta, Vijai; Gurunathan, Selvakumar; Rangappa, Shobith; Huntrike, Shekar Shetty; Srivastava, Rakesh Kumar

    2017-01-01

    Endophytic Trichoderma hamatum UoM 13 isolated from pearl millet roots was evaluated for its efficiency to suppress downy mildew disease. Under laboratory conditions, T. hamatum seed treatment significantly enhanced pearl millet seed germination and seedling vigor. T. hamatum seed treatment resulted in systemic and durable immunity against pearl millet downy mildew disease under greenhouse and field conditions. T. hamatum treated seedlings responded to downy mildew infection with high lignification and callose deposition. Analysis of defense enzymes showed that T. hamatum treatment significantly enhanced the activities of glucanase, peroxidase, phenylalanine ammonia-lyase, and polyphenol oxidase in comparison to untreated control. RT-PCR analysis revealed differentially expressed transcripts of the defense enzymes and PR-proteins in treated, untreated, and checks, wherein PR-1, PR-5, and cell wall defense HRGPs were significantly over expressed in treated seedlings as against their lower expression in controls. T. hamatum treatment significantly stimulated endogenous salicylic acid (SA) levels and significantly upregulated important SA biosynthesis gene isochorismate synthase. The results indicated that T. hamatum UoM13 treatment induces resistance corresponding to significant over expression of endogenous SA, important defense enzymes, PR-proteins, and HRGPs, suggesting that SA biosynthetic pathway is involved in pearl millet for mounting systemic immunity against downy mildew pathogen. PMID:28322224

  2. Pl17 is a novel gene independent of known downy mildew resistance genes in the cultivated sunflower (Helianthus annuus L.)

    Science.gov (United States)

    Downy mildew (DM), caused by Plasmopara halstedii (Farl.) Berl. et de Toni, is one of the serious sunflower diseases in the world due to its high virulence and the variability of the pathogen. DM resistance in the USDA inbred line, HA 458, has been shown to be effective against all virulent races of...

  3. Extracts of Inula viscosa Control Downy Mildew of Grapes Caused by Plasmopara viticola.

    Science.gov (United States)

    Cohen, Yigal; Wang, Wenqiao; Ben-Daniel, Bat-Hen; Ben-Daniel, Yigal

    2006-04-01

    ABSTRACT The oily paste extracts of Inula viscosa leaves made with organic solvents were effective in controlling downy mildew caused by Plasmopara viticola in detached leaf tissues of grapes in growth chambers. Thin-layer chromatography of such extracts revealed the presence of 11 Rf regions of which four contained highly effective compounds against the disease. Two major inhibitory compounds, each comprising 10.6% of the total paste weight, were identified as tomentosin and costic acid. An emulsified concentrate formulation of the oily paste extracts provided excellent activity against the disease in the field. The effective dose (concentration) required for 90% control of the disease in treated shoots in the field was below 0.125% (paste in water). No seasonal fluctuations were observed in the control efficacy of six extracts made from I. viscosa leaves harvested during the period of May to July. In whole vines, treated and artificially inoculated, the paste concentration required for 90% control of the disease ranged between 0.30 to 0.37%, whereas in naturally infected vines it was 0.58%. It appears that I. viscosa is a valuable source for fungicidal preparations against downy mildew of grapes. This is the first report on the control of a disease with I. viscosa extracts under field conditions.

  4. Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce.

    Science.gov (United States)

    Simko, Ivan; Atallah, Amy J; Ochoa, Oswaldo E; Antonise, Rudie; Galeano, Carlos H; Truco, Maria Jose; Michelmore, Richard W

    2013-10-07

    Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids.

  5. Cloning and Expression Analysis of Downy Mildew Resistance-Related cDNA Sequences in Melon

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Melon downy mildew caused by Pseudoperonospora cubensis leads to significant losses in melon yields worldwide.Reverse-transcription Polymerase Chain Reaction (RT-PCR) was performed using cDNAs as templates from melonHuangdanzi induced with fungus Pseudoperonospora cubensis, and degenerate primers designed based on the conserved amino acid sequences of known plant disease-resistance genes. A polymorphic cDNA fragment which we named mp-19was cloned and sequenced. The Open Reading Frame (ORF) of this product comprised of 510 base pairs which encodes DNA or RNA-binding protein with 170 amino acids. The putative amino acid sequence of mp-19 appeared highly homologous with those of NBS-type resistant-genes isolated from other plants. Southern blot indicated that the melon genome contained more than 3 copies of mp-19. The obvious expression differences detected by semi-quantitative RTPCR could be observed between resistant-line Huangdanzi and susceptible-line Jiashi after Pseudoperonospora cubensis infection, which implied that mp-19 gene may be related to the resistance of downy mildew in melon.

  6. GENETIC DIVERSITY OF S3 MAIZE GENOTYPES RESISTANT TO DOWNY MILDEW BASED ON SSR MARKERS

    Directory of Open Access Journals (Sweden)

    Amran Muis

    2016-02-01

    Full Text Available The compulsory requirement for releasing new high yielding maize varieties is resistance to downy mildew. The study aimed to determine the level of homozygosity, genetic diversity, and  genetic distance of 30 S3 genotypes of maize. Number of primers to be used were 30 polymorphic SSR loci which are distributed over the entire maize genomes. The S3 genotypes used were resistant to downy mildew with homozygosity level of >80%, genetic distance between the test and tester strains >0.7, and anthesis silking interval (ASI between inbred lines and tester lines was maximum 3 days. The results showed that 30 SSR primers used were spread evenly across the maize genomes which were manifested in the representation of SSR loci on each chromosome of a total of 10 chromosomes. The levels of polymorphism ranged from 0.13 to 0.78, an average of 0.51, and the number of alleles ranged from 2 to 8 alleles per SSR locus, an average of 4 alleles per SSR locus. The size of nucleotides in each locus also varied from 70 to 553 bp. Cophenetic correlation value (r at 0.67 indicated that the Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA was less reliable for differentiating genotypes in five groups. Of the total of 30 genotypes analyzed, 17 genotypes had homozygosity level of >80% so it can be included in the hybrid assembly program.

  7. Morphological and molecular characterization of the causal agent of downy mildew on Quinoa (Chenopodium quinoa).

    Science.gov (United States)

    Choi, Young-Joon; Danielsen, Solveig; Lübeck, Mette; Hong, Seung-Beom; Delhey, Rolf; Shin, Hyeon-Dong

    2010-05-01

    Downy mildew is an economically important and widespread disease in quinoa (Chenopodium quinoa) growing areas. Although in many studies Peronospora farinosa is most commonly regarded as the causal agent of the disease, identification and classification of the pathogen remain still uncertain due to its taxonomic confusion. Thirty-six Peronospora isolates from quinoa with different geographic origins including Argentina, Bolivia, Denmark, Ecuador, and Peru were morphologically and molecularly compared with Peronospora species from other Chenopodium species. The morphology of three herbarium specimens was similar to that of P. variabilis, which originated from C. album, characterized by flexuous to curved ultimate branchlets and pedicellated conidia. Phylogenetic analysis based on ITS rDNA sequences also placed the quinoa pathogen within the same clade as P. variabilis. Within the ITS rDNA sequences of the quinoa pathogens, two base substitutions were found, which separated the majority of the Danish isolates from isolates from South America, but no sequence difference was found among the isolates from different cultivars of quinoa. The present results indicate that the pathogen responsible for the quinoa downy mildew is identical to Peronospora variabilis and that it should not be lumped with P. farinosa as claimed previously by most studies.

  8. Transcriptome and Small RNAome Dynamics during a Resistant and Susceptible Interaction between Cucumber and Downy Mildew

    Directory of Open Access Journals (Sweden)

    Alyssa Burkhardt

    2016-03-01

    Full Text Available Cucumber ( L. downy mildew, caused by the obligate oomycete pathogen (Berk. and Curt. Rostov., is the primary factor limiting cucumber production. Although sources of resistance have been identified, such as plant introduction line PI 197088, the genes and processes involved in mediating resistance are still unknown. In the current study, we conducted a comprehensive transcriptome and small RNAome analysis of a resistant (PI 197088 and susceptible (‘Vlaspik’ cucumber during a time course of infection using Illumina sequencing. We identified significantly differentially expressed (DE genes within and between resistant and susceptible cucumber leaves over a time course of infection. Weighted gene correlation network analyses (WGCNA created coexpression modules containing genes with unique expression patterns between Vlaspik and PI 197088. Recurring data trends indicated that resistance to cucumber downy mildew is associated with earlier response to the pathogen, hormone signaling, and regulation of nutrient supply. Candidate resistance genes were identified from multiple transcriptome analyses and literature support. Additionally, parallel sequencing of small RNAs (sRNAs from cucumber and during the infection time course was used to identify and quantify novel and existing microRNA (miRNA in both species. Predicted miRNA targets of cucumber transcripts suggest a complex interconnectedness of gene expression regulation in this plant–pathogen system. This work bioinformatically uncovered gene expression patterns involved in the mediation of or response to resistance. Herein, we provide the foundation for future work to validate candidate resistance genes and miRNA-based regulation proposed in this study.

  9. Downy mildew resistance induced by Trichoderma harzianum T39 in susceptible grapevines partially mimics transcriptional changes of resistant genotypes

    Directory of Open Access Journals (Sweden)

    Perazzolli Michele

    2012-11-01

    Full Text Available Abstract Background Downy mildew, caused by Plasmopara viticola, is one of the most severe diseases of grapevine and is commonly controlled by fungicide treatments. The beneficial microorganism Trichoderma harzianum T39 (T39 can induce resistance to downy mildew, although the molecular events associated with this process have not yet been elucidated in grapevine. A next generation RNA sequencing (RNA-Seq approach was used to study global transcriptional changes associated with resistance induced by T39 in Vitis vinifera Pinot Noir leaves. The long-term aim was to develop strategies to optimize the use of this agent for downy mildew control. Results More than 14.8 million paired-end reads were obtained for each biological replicate of T39-treated and control leaf samples collected before and 24 h after P. viticola inoculation. RNA-Seq analysis resulted in the identification of 7,024 differentially expressed genes, highlighting the complex transcriptional reprogramming of grapevine leaves during resistance induction and in response to pathogen inoculation. Our data show that T39 has a dual effect: it directly modulates genes related to the microbial recognition machinery, and it enhances the expression of defence-related processes after pathogen inoculation. Whereas several genes were commonly affected by P. viticola in control and T39-treated plants, opposing modulation of genes related to responses to stress and protein metabolism was found. T39-induced resistance partially inhibited some disease-related processes and specifically activated defence responses after P. viticola inoculation, causing a significant reduction of downy mildew symptoms. Conclusions The global transcriptional analysis revealed that defence processes known to be implicated in the reaction of resistant genotypes to downy mildew were partially activated by T39-induced resistance in susceptible grapevines. Genes identified in this work are an important source of markers

  10. Breakdown of resistance to grapevine downy mildew upon limited deployment of a resistant variety

    Directory of Open Access Journals (Sweden)

    Bellin Diana

    2010-07-01

    Full Text Available Abstract Background Natural disease resistance is a cost-effective and environmentally friendly way of controlling plant disease. Breeding programmes need to make sure that the resistance deployed is effective and durable. Grapevine downy mildew, caused by the Oomycete Plasmopara viticola, affects viticulture and it is controlled with pesticides. Downy mildew resistant grapevine varieties are a promising strategy to control the disease, but their use is currently restricted to very limited acreages. The arising of resistance-breaking isolates under such restricted deployment of resistant varieties would provide valuable information to design breeding strategies for the deployment of resistance genes over large acreages whilst reducing the risks of the resistance being defeated. The observation of heavy downy mildew symptoms on a plant of the resistant variety Bianca, whose resistance is conferred by a major gene, provided us with a putative example of emergence of a resistance-breaking isolate in the interaction between grapevine and P. viticola. Results In this paper we describe the emergence of a P. viticola isolate (isolate SL that specifically overcomes Rpv3, the major resistance gene carried by Bianca at chromosome 18. We show that isolate SL has the same behaviour as two P. viticola isolates avirulent on Bianca (isolates SC and SU when inoculated on susceptible plants or on resistant plants carrying resistances derived from other sources, suggesting there is no fitness cost associated to the virulence. Molecular analysis shows that all three isolates are genetically closely related. Conclusions Our results are the first description of a resistance-breaking isolate in the grapevine/P. viticola interaction, and show that, despite the reduced genetic variability of P. viticola in Europe compared to its basin of origin and the restricted use of natural resistance in European viticulture, resistance-breaking isolates overcoming monogenic

  11. Characterization of a Brome mosaic virus strain and its use as a vector for gene silencing in monocotyledonous hosts.

    Science.gov (United States)

    Ding, Xin Shun; Schneider, William L; Chaluvadi, Srinivasa Rao; Mian, M A Rouf; Nelson, Richard S

    2006-11-01

    Virus-induced gene silencing (VIGS) is used to analyze gene function in dicotyledonous plants but less so in monocotyledonous plants (particularly rice and corn), partially due to the limited number of virus expression vectors available. Here, we report the cloning and modification for VIGS of a virus from Festuca arundinacea Schreb. (tall fescue) that caused systemic mosaic symptoms on barley, rice, and a specific cultivar of maize (Va35) under greenhouse conditions. Through sequencing, the virus was determined to be a strain of Brome mosaic virus (BMV). The virus was named F-BMV (F for Festuca), and genetic determinants that controlled the systemic infection of rice were mapped to RNAs 1 and 2 of the tripartite genome. cDNA from RNA 3 of the Russian strain of BMV (R-BMV) was modified to accept inserts from foreign genes. Coinoculation of RNAs 1 and 2 from F-BMV and RNA 3 from R-BMV expressing a portion of a plant gene to leaves of barley, rice, and maize plants resulted in visual silencing-like phenotypes. The visual phenotypes were correlated with decreased target host transcript levels in the corresponding leaves. The VIGS visual phenotype varied from maintained during silencing of actin 1 transcript expression to transient with incomplete penetration through affected tissue during silencing of phytoene desaturase expression. F-BMV RNA 3 was modified to allow greater accumulation of virus while minimizing virus pathogenicity. The modified vector C-BMV(A/G) (C for chimeric) was shown to be useful for VIGS. These BMV vectors will be useful for analysis of gene function in rice and maize for which no VIGS system is reported.

  12. Multi-Dimensional Analysis of Large, Complex Slope Instability: Case study of Downie Slide, British Columbia, Canada. (Invited)

    Science.gov (United States)

    Kalenchuk, K. S.; Hutchinson, D.; Diederichs, M. S.

    2013-12-01

    Downie Slide, one of the world's largest landslides, is a massive, active, composite, extremely slow rockslide located on the west bank of the Revelstoke Reservoir in British Columbia. It is a 1.5 billion m3 rockslide measuring 2400 m along the river valley, 3300m from toe to headscarp and up to 245 m thick. Significant contributions to the field of landslide geomechanics have been made by analyses of spatially and temporally discriminated slope deformations, and how these are controlled by complex geological and geotechnical factors. Downie Slide research demonstrates the importance of delineating massive landslides into morphological regions in order to characterize global slope behaviour and identify localized events, which may or may not influence the overall slope deformation patterns. Massive slope instabilities do not behave as monolithic masses, rather, different landslide zones can display specific landslide processes occurring at variable rates of deformation. The global deformation of Downie Slide is extremely slow moving; however localized regions of the slope incur moderate to high rates of movement. Complex deformation processes and composite failure mechanism are contributed to by topography, non-uniform shear surfaces, heterogeneous rockmass and shear zone strength and stiffness characteristics. Further, from the analysis of temporal changes in landslide behaviour it has been clearly recognized that different regions of the slope respond differently to changing hydrogeological boundary conditions. State-of-the-art methodologies have been developed for numerical simulation of large landslides; these provide important tools for investigating dynamic landslide systems which account for complex three-dimensional geometries, heterogenous shear zone strength parameters, internal shear zones, the interaction of discrete landslide zones and piezometric fluctuations. Numerical models of Downie Slide have been calibrated to reproduce observed slope behaviour

  13. Use of suppression subtractive hybridization to identify downy mildew genes expressed during infection of Arabidopsis thaliana.

    Science.gov (United States)

    Bittner-Eddy, Peter D; Allen, Rebecca L; Rehmany, Anne P; Birch, Paul; Beynon, Jim L

    2003-11-01

    SUMMARY Peronospora parasitica is an obligate biotrophic oomycete that causes downy mildew in Arabidopsis thaliana and Brassica species. Our goal is to identify P. parasitica (At) genes that are involved in pathogenicity. We used suppression subtractive hybridization (SSH) to generate cDNA libraries enriched for in planta-expressed parasite genes and up-regulated host genes. A total of 1345 clones were sequenced representing cDNA fragments from 25 putative P. parasitica (At) genes (Ppat 1-25) and 618 Arabidopsis genes. Analyses of expression patterns showed that 15 Ppats were expressed only in planta. Eleven Ppats encoded peptides with homology (BlastP values planta-expressed genes from P. parasitica (At) that complements other gene discovery approaches such as EST sequencing.

  14. Genetic dissection of sex determinism, inflorescence morphology and downy mildew resistance in grapevine.

    Science.gov (United States)

    Marguerit, Elisa; Boury, Christophe; Manicki, Aurélie; Donnart, Martine; Butterlin, Gisèle; Némorin, Alice; Wiedemann-Merdinoglu, Sabine; Merdinoglu, Didier; Ollat, Nathalie; Decroocq, Stéphane

    2009-05-01

    A genetic linkage map of grapevine was constructed using a pseudo-testcross strategy based upon 138 individuals derived from a cross of Vitis vinifera Cabernet Sauvignon x Vitis riparia Gloire de Montpellier. A total of 212 DNA markers including 199 single sequence repeats (SSRs), 11 single strand conformation polymorphisms (SSCPs) and two morphological markers were mapped onto 19 linkage groups (LG) which covered 1,249 cM with an average of 6.7 cM between markers. The position of SSR loci in the maps presented here is consistent with the genome sequence. Quantitative traits loci (QTLs) for several traits of inflorescence and flower morphology, and downy mildew resistance were investigated. Two novel QTLs for downy mildew resistance were mapped on linkage groups 9 and 12, they explain 26.0-34.4 and 28.9-31.5% of total variance, respectively. QTLs for inflorescence morphology with a large effect (14-70% of total variance explained) were detected close to the Sex locus on LG 2. The gene of the enzyme 1-aminocyclopropane-1-carboxylic acid synthase, involved in melon male organ development and located in the confidence interval of all QTLs detected on the LG 2, could be considered as a putative candidate gene for the control of sexual traits in grapevine. Co-localisations were found between four QTLs, detected on linkage groups 1, 14, 17 and 18, and the position of the floral organ development genes GIBBERELLIN INSENSITIVE1, FRUITFULL, LEAFY and AGAMOUS. Our results demonstrate that the sex determinism locus also determines both flower and inflorescence morphological traits.

  15. Polygalacturonase-inhibitor proteins in pearl millet: possible involvement in resistance against downy mildew

    Institute of Scientific and Technical Information of China (English)

    S. Ashok Prabhu; K. Ramachandra Kini; S. Niranjan Raj; Bruno M. Moerschbacher; H. S. Shetty

    2012-01-01

    Polygalacturonase-inhibitor protein (PGIP) is a defense protein found in plant cell walls.It prevents the degradation of pectin by modulating the endo-polygalacturonase activity.The present study has used heterologous antibean PGIP probes to investigate the role of PGIP in pearl millet [Pennisetum glaucum (L) R.Br.] resistance against downy mildew caused by oomycete pathogen Sclerospora graminicola (Sacc.) Schroet.Northern blot analysis using bean pgip2 DNA fragment as probe showed an early and marked induction of transcripts (~1.2 kb) upon pathogen-inoculation in pearl millet cultivar resistant to downy mildew,with the maximum level observed at 24 and 48 h post-inoculation (h.p.i.).Western blot analysis of pearl millet total cell wall proteins using antibodies against bean PGIP showed the presence of a major band of ~43 kDa,and several minor ones.The protein accumulation was higher in resistant seedlings than in susceptible seedlings with a differential expression observed only in the case of incompatible interaction.lmmunocytochemical localization in epidermal peelings of coleoptiles and tissue-printing showed a similar trend in the PGIP accumulation.PGIP was found to localize in the epidermal as well as in the vascular regions of tissues.Higher accumulation was observed in the stomatal guard cells of resistant cultivar inoculated with the pathogen.PGIP activity of pearl millet total protein extracts when assayed against Aspergillus niger PG displayed differential PG inhibitory activities between the resistant and suceptible cultivars with resistant sample showing the highest inhibition of 16%,post-pathogen treatment.Thus,PGIP appeared to be an important player in pearl millet-S,graminicola interaction leading to host resistance.

  16. Nitric oxide donor seed priming enhances defense responses and induces resistance against pearl millet downy mildew disease

    DEFF Research Database (Denmark)

    Manjunatha, G.; Raj, S. Niranjan; Shetty, Nandini Prasad

    2008-01-01

    , a structural analog of NO donor lacking NO moiety failed to protect the pearl millet plants from downy mildew indicating a role for NO in induced host resistance. Spatio-temporal studies corroborated that the protection offered by NO donor treatment was systemic in nature and a minimum of 3-day time gap...... experiments with NO donors showed no adverse effect either on the host or pathogen. Aqueous SNP seed treatment with or without polyethylene glycol (PEG) priming was the most effective in inducing the host resistance against downy mildew both under greenhouse and field conditions. Potassium Ferrocyanide...... between the inducer treatment and subsequent pathogen inoculation was necessary for maximum resistance development. Disease protection ability of NO donors was also validated as durable in nature. Conversely, prior-treatment with NO scavenger 2-4-carboxyphenyl-4,4,5,5 tetrazoline-1-oxyl-3-oxide potassium...

  17. Impact of major gene resistance management for sunflower on fitness of Plasmopara halstedii (downy mildew populations

    Directory of Open Access Journals (Sweden)

    Tourvieille de Labrouhe Denis

    2010-01-01

    Full Text Available Changes in virulence of Plasmopara halstedii populations under different major gene (Pl management strategies were studied over 5 years continuous cropping of one sunflower hybrid under netting cages. Strategies were monoculture of forms of the hybrid with 1 gene or with combinations of 2 genes, alternation of different genes, and mixtures of several different forms of the hybrid. Monoculture with single resistance genes led to loss of efficient resistance after 3 years, with high levels of disease and increased variability of the pathogen, whatever the Pl gene used. Combinations of genes, alternation and mixtures gave longer term control of downy mildew. In particular, combinations of resistance genes coming from both female and male parents of the hybrid (such that even impurities had a resistance gene gave the best control and least variation in pathogen virulence. Results are discussed with the object of durable control of downy mildew by all methods available.

  18. High dilutions of Sulphur and relationship with the onion thrips, downy mildew incidence and yield of onion in organic system

    Directory of Open Access Journals (Sweden)

    Paulo Antonio de Souza Gonçalves

    2015-12-01

    Full Text Available The objective of this research was to evaluate high dilutions of Sulphur on the incidence of onion thrips, downy mildew, chlorophyll content and yield of onion under organic production system. The study was carried out at Ituporanga Experiment Station of Epagri, Santa Catarina State, Brazil, from August to December of 2011, 2012 and 2013. Treatments were foliar sprays of 0.5% Sulphur at high dilutions 6, 12 and 30 CH (CH, hahnemannian centesimal scale and untreated plot as control check. The experimental design was a randomized block design with four replications. The incidence and damage of onion thrips, reduction of the severity of downy mildew, chlorophyll index, total and commercial yield, bulb weight, postharvest conservation were not influenced by the treatments.

  19. Development and dissection of diagnostic SNP markers for the downy mildew resistance genes PlArg and Pl8 and maker-assisted gene pyramiding in sunflower (Helianthus annuus L.)

    Science.gov (United States)

    Downy mildew, which is caused by fungus Plasmopara halstedii (Farl.) Berlese & de Toni, is one of the most important diseases that affect sunflower production globally. Two downy mildew resistance genes, PlArg and Pl8, were discovered in the late 1980s. Over two decades, PlArg is still effective aga...

  20. Decay of genes encoding the oomycete flagellar proteome in the downy mildew Hyaloperonospora arabidopsidis.

    Directory of Open Access Journals (Sweden)

    Howard S Judelson

    Full Text Available Zoospores are central to the life cycles of most of the eukaryotic microbes known as oomycetes, but some genera have lost the ability to form these flagellated cells. In the plant pathogen Phytophthora infestans, genes encoding 257 proteins associated with flagella were identified by comparative genomics. These included the main structural components of the axoneme and basal body, proteins involved in intraflagellar transport, regulatory proteins, enzymes for maintaining ATP levels, and others. Transcripts for over three-quarters of the genes were up-regulated during sporulation, and persisted to varying degrees in the pre-zoospore stage (sporangia and motile zoospores. Nearly all of these genes had orthologs in other eukaryotes that form flagella or cilia, but not species that lack the organelle. Orthologs of 211 of the genes were also absent from a sister taxon to P. infestans that lost the ability to form flagella, the downy mildew Hyaloperonospora arabidopsidis. Many of the genes retained in H. arabidopsidis were also present in other non-flagellates, suggesting that they play roles both in flagella and other cellular processes. Remnants of the missing genes were often detected in the H. arabidopsidis genome. Degradation of the genes was associated with local compaction of the chromosome and a heightened propensity towards genome rearrangements, as such regions were less likely to share synteny with P. infestans.

  1. Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing.

    Science.gov (United States)

    Stassen, Joost H M; Seidl, Michael F; Vergeer, Pim W J; Nijman, Isaäc J; Snel, Berend; Cuppen, Edwin; Van den Ackerveken, Guido

    2012-09-01

    Lettuce downy mildew (Bremia lactucae) is a rapidly adapting oomycete pathogen affecting commercial lettuce cultivation. Oomycetes are known to use a diverse arsenal of secreted proteins (effectors) to manipulate their hosts. Two classes of effector are known to be translocated by the host: the RXLRs and Crinklers. To gain insight into the repertoire of effectors used by B. lactucae to manipulate its host, we performed massively parallel sequencing of cDNA derived from B. lactucae spores and infected lettuce (Lactuca sativa) seedlings. From over 2.3 million 454 GS FLX reads, 59 618 contigs were assembled representing both plant and pathogen transcripts. Of these, 19 663 contigs were determined to be of B. lactucae origin as they matched pathogen genome sequences (SOLiD) that were obtained from >270 million reads of spore-derived genomic DNA. After correction of cDNA sequencing errors with SOLiD data, translation into protein models and filtering, 16 372 protein models remained, 1023 of which were predicted to be secreted. This secretome included elicitins, necrosis and ethylene-inducing peptide 1-like proteins, glucanase inhibitors and lectins, and was enriched in cysteine-rich proteins. Candidate host-translocated effectors included 78 protein models with RXLR effector features. In addition, we found indications for an unknown number of Crinkler-like sequences. Similarity clustering of secreted proteins revealed additional effector candidates. We provide a first look at the transcriptome of B. lactucae and its encoded effector arsenal.

  2. Research Progress of Induced Resistance to Cucumber Downy Mildew%黄瓜霜霉病诱导抗性的研究进展

    Institute of Scientific and Technical Information of China (English)

    侯丽琴; 李长松; 徐作珽; 李林; 齐军山; 张博; 杨革

    2012-01-01

    Cucumber downy mildew is a worldwide disease, and also an destructive disease in protected cucumber production. The disease spreads fast and has a great threat to cucumber production. In this paper, the research progress of inducer types to cucumber downy mildew, induced mechanism and relevant genes on downy mildew resistance were reviewed and summarized, and then the developing trend was prospected.%黄瓜霜霉病是一种世界性病害,也是保护地黄瓜生产上的一种毁灭性病害.本文概述了黄瓜霜霉病诱抗剂种类、诱抗机制、抗霜霉病相关基因等方面的研究进展,并对未来发展趋势提出了展望.

  3. Response of sorghum accessions from Chad and Uganda to natural infection by the downy mildew pathogen, Peronosclerospora sorghi in Mexico and the USA

    Science.gov (United States)

    In this study, 78 accessions from Chad, West Africa and 20 photoperiod insensitive accessions from Uganda, East Africa were evaluated for downy mildew resistance in Ocotlan, Mexico in 2004 and 2005. Ninety-four of these accessions were also evaluated at two locations in Wharton County, Texas, USA, ...

  4. Lactuca saligna, a non-host for lettuce downy mildew (Bremia lactucae), harbors a new race-specific Dm gene and three QTL's for resistance

    NARCIS (Netherlands)

    Jeuken, M.J.W.; Lindhout, P.

    2002-01-01

    Lactuca sativa (lettuce) is susceptible to Bremia lactucae (downy mildew). In cultivated and wild Lactuca species, Dm genes have been identified that confer race-specific resistance. However, these genes were soon rendered ineffective by adaptation of the pathogen. Lactuca saligna (wild lettuce) is

  5. Screening exotic sorghum germplasm, hybrids and elite lines for resistance to a new virulent pathotype (P6) of Peronsclerospora sorghi causing downy mildew

    Science.gov (United States)

    A recent outbreak of sorghum downy mildew (SDM) in Texas has led to the discovery of both metalaxyl fungicide resistance and a new pathotype, P6, in the causal organism Peronsclerospora sorghi. New and alternate sources of the host plant resistance are needed for successful management of SDM. To i...

  6. Genetic signature of a range expansion and leap-frog event after the recent invasion of Europe by the grapevine downy mildew pathogen Plasmopara viticola

    NARCIS (Netherlands)

    Fontaine, Michael C.; Austerlitz, Frederic; Giraud, Tatiana; Labbe, Frederic; Papura, Daciana; Richard-Cervera, Sylvie; Delmotte, Francois

    2013-01-01

    Biologic invasions can have important ecological, economic and social consequences, particularly when they involve the introduction and spread of plant invasive pathogens, as they can threaten natural ecosystems and jeopardize the production of human food. Examples include the grapevine downy mildew

  7. Growth and Decline and Control Countermeasures of Grape Downy Mildew%葡萄霜霉病田间消长规律及防治对策

    Institute of Scientific and Technical Information of China (English)

    马俊义; 范咏梅; 姜新丽; 刘新智; 周泽容; 韩先旭

    2011-01-01

    [目的]调查研究葡萄霜霉病的田间流行动态,以期提出合理的用药时间和药剂种类.[方法]采用5点法对新疆北部昌吉市葡萄霜霉病的田间消长规律进行调查,采用叶盘法测定不同药剂对葡萄藉霉病菌的敏感性;采用生测法筛选葡萄霜霉病田间药剂.[结果]6-7月降雨量和降雨次数是导致北疆葡萄霜霉病流行的主要因子之一.霜疫必克、杜邦易保对葡萄霜霉病菌表现出较强的毒力,对葡萄霜霉病菌比较敏感,属一个敏感水平,杀毒矾次之,而甲霜灵对葡萄霜霉菌表现出极不敏感.通过两年对10种药剂的田间药效试验表明:在葡萄霜霉病发病期喷施安克、霜疫必克、杀毒矾,隔7d喷一次,连续喷2次,相对防效达61.59%-71.70%,比其它药剂防效明显.[结论]新疆昌吉葡萄霜霉病的发生危害程度与降雨日持续时间和雨量大小呈一定的相关性.安克、霜疫必克、杀毒矾三种杀菌剂具有良好控制病害蔓延效果,且属低毒农药,对葡萄安全,对环境污染小,值得推广应用.%[ Objective]ln this paper, Crape downy mildew epidemic dynamics were investigated in Xinjiang in order to provide reasonable treatment time and type of chemicals against the disease. [Method ] By 5 - point method, epidemic dynamic of grape downy mildew was investigated in Changji city in northem Xinjiang; using the leaf disc method , it was determined for the aensitivity of different fungicides to the pathogen of grape downy mildew; the fungicides which were sensitive to grape downy mildew were screened by bioassay. [ Result]ln June and July, the amount of precipitation is one major factor which led to the popular of grape downy mildew in northem Xinjiang. The fungicides (SYBK and DuPont) showed strong virulence to grape downy mildew pathogen , more sensitive to downy mildew of grape than other fungicides, such as Oxadixyl+ Mancozeb, and metalaxyl on grape downy mildew pathogen were very

  8. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: Implications for replication and genome packaging

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Sonali; Rao, A.L.N., E-mail: arao@ucr.edu

    2014-09-15

    In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein–protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed. - Highlights: • YFP fusion proteins of BMV p1a and p2a are biologically active. • Self-interaction was observed for p1a, p2a and CP. • CP interacts with p2a but not p1a. • Majority of reconstituted YFP resulting from bona fide fusion protein partners localized on ER.

  9. Downregulation of the NbNACa1 gene encoding a movement-protein-interacting protein reduces cell-to-cell movement of Brome mosaic virus in Nicotiana benthamiana.

    Science.gov (United States)

    Kaido, Masanori; Inoue, Yosuke; Takeda, Yoshika; Sugiyama, Kazuhiko; Takeda, Atsushi; Mori, Masashi; Tamai, Atsushi; Meshi, Tetsuo; Okuno, Tetsuro; Mise, Kazuyuki

    2007-06-01

    The 3a movement protein (MP) plays a central role in the movement of the RNA plant virus, Brome mosaic virus (BMV). To identify host factor genes involved in viral movement, a cDNA library of Nicotiana benthamiana, a systemic host for BMV, was screened with far-Western blotting using a recombinant BMV MP as probe. One positive clone encoded a protein with sequence similarity to the alpha chain of nascent-polypeptide-associated complex from various organisms, which is proposed to contribute to the fidelity of translocation of newly synthesized proteins. The orthologous gene from N. benthamiana was designated NbNACa1. The binding of NbNACa1 to BMV MP was confirmed in vivo with an agroinfiltration-immunoprecipitation assay. To investigate the involvement of NbNACa1 in BMV multiplication, NbNACa1-silenced (GSNAC) transgenic N. benthamiana plants were produced. Downregulation of NbNACa1 expression reduced virus accumulation in inoculated leaves but not in protoplasts. A microprojectile bombardment assay to monitor BMV-MP-assisted viral movement demonstrated reduced virus spread in GSNAC plants. The localization to the cell wall of BMV MP fused to green fluorescent protein was delayed in GSNAC plants. From these results, we propose that NbNACa1 is involved in BMV cell-to-cell movement through the regulation of BMV MP localization to the plasmodesmata.

  10. Occurrence and control of Wheat Downy Mildew%小麦霜霉病的发生与防治

    Institute of Scientific and Technical Information of China (English)

    秦玉芬

    2013-01-01

    小麦霜霉病是一种以土壤传染为主的真菌病害,主要在苗期阶段侵染.在防治上我们通过采取以轮作、选种抗病品种、加强肥水管理和药剂拌种等综合防治措施,使其得到了有效控制.%The wheat downy mildew is a kind of fungi diseases which are mainly infected by soil and the wheat ismainly contaminated during seeding stage.In prevention,we mainly take comprehensive preventive health measures such as rotation,choosing disease-resistant seed,the enhancement the management of fertilizer and water,medicament mixed with seed etc to extend effective control.

  11. Toward the Identification of Two Glycoproteins Involved in the Stomatal Deregulation of Downy Mildew-Infected Grapevine Leaves.

    Science.gov (United States)

    Guillier, Christelle; Gamm, Magdalena; Lucchi, Géraldine; Truntzer, Caroline; Pecqueur, Delphine; Ducoroy, Patrick; Adrian, Marielle; Héloir, Marie-Claire

    2015-11-01

    Stomata remain abnormally opened and unresponsive to abscisic acid in grapevine leaves infected by downy mildew. This deregulation occurs from 3 days postinoculation and increases concomitantly with leaf colonization by the pathogen. Using epidermal peels, we demonstrated that the active compound involved in this deregulation is located in the apoplast. Biochemical assays showed that the active compound present in the apoplastic fluids isolated from Plasmopara viticola-infected grapevine leaves (IAF) is a CysCys bridge-independent, thermostable and glycosylated protein. Fractionation guided assays based on chromatography coupled to stomatal response and proteomic analysis allowed the identification of both plant and pathogen proteins in the active fraction obtained from IAF. Further in silico analysis and discriminant filtrations based on the comparison between predictions and experimental indications lead to the identification of two Vitis vinifera proteins as candidates for the observed stomatal deregulation.

  12. Resistance to Downy Mildew in Lettuce 'La Brillante' is Conferred by Dm50 Gene and Multiple QTL.

    Science.gov (United States)

    Simko, Ivan; Ochoa, Oswaldo E; Pel, Mathieu A; Tsuchida, Cayla; Font I Forcada, Carolina; Hayes, Ryan J; Truco, Maria-Jose; Antonise, Rudie; Galeano, Carlos H; Michelmore, Richard W

    2015-09-01

    Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar 'La Brillante' has a high level of field resistance to the disease in California. Testing of a mapping population developed from a cross between 'Salinas 88' and La Brillante in multiple field and laboratory experiments revealed that at least five loci conferred resistance in La Brillante. The presence of a new dominant resistance gene (designated Dm50) that confers complete resistance to specific isolates was detected in laboratory tests of seedlings inoculated with multiple diverse isolates. Dm50 is located in the major resistance cluster on linkage group 2 that contains at least eight major, dominant Dm genes conferring resistance to downy mildew. However, this Dm gene is ineffective against the isolates of B. lactucae prevalent in the field in California and the Netherlands. A quantitative trait locus (QTL) located at the Dm50 chromosomal region (qDM2.2) was detected, though, when the amount of disease was evaluated a month before plants reached harvest maturity. Four additional QTL for resistance to B. lactucae were identified on linkage groups 4 (qDM4.1 and qDM4.2), 7 (qDM7.1), and 9 (qDM9.2). The largest effect was associated with qDM7.1 (up to 32.9% of the total phenotypic variance) that determined resistance in multiple field experiments. Markers identified in the present study will facilitate introduction of these resistance loci into commercial cultivars of lettuce.

  13. [An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

    Science.gov (United States)

    Wang, Hui; Li, Mei-lan; Xu, Jian-ping; Chen, Mei-xiang; Li, Wen-yong; Li, Ming

    2015-10-01

    The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.

  14. Historical introgression of the downy mildew resistance gene Rpv12 from the Asian species Vitis amurensis into grapevine varieties.

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    Silvia Venuti

    Full Text Available The Amur grape (Vitis amurensis Rupr. thrives naturally in cool climates of Northeast Asia. Resistance against the introduced pathogen Plasmopara viticola is common among wild ecotypes that were propagated from Manchuria into Chinese vineyards or collected by Soviet botanists in Siberia, and used for the introgression of resistance into wine grapes (Vitis vinifera L.. A QTL analysis revealed a dominant gene Rpv12 that explained 79% of the phenotypic variance for downy mildew resistance and was inherited independently of other resistance genes. A Mendelian component of resistance-a hypersensitive response in leaves challenged with P. viticola-was mapped in an interval of 0.2 cM containing an array of coiled-coil NB-LRR genes on chromosome 14. We sequenced 10-kb genic regions in the Rpv12(+ haplotype and identified polymorphisms in 12 varieties of V. vinifera using next-generation sequencing. The combination of two SNPs in single-copy genes flanking the NB-LRR cluster distinguished the resistant haplotype from all others found in 200 accessions of V. vinifera, V. amurensis, and V. amurensis x V. vinifera crosses. The Rpv12(+ haplotype is shared by 15 varieties, the most ancestral of which are the century-old 'Zarja severa' and 'Michurinets'. Before this knowledge, the chromosome segment around Rpv12(+ became introgressed, shortened, and pyramided with another downy mildew resistance gene from North American grapevines (Rpv3 only by phenotypic selection. Rpv12(+ has an additive effect with Rpv3(+ to protect vines against natural infections, and confers foliar resistance to strains that are virulent on Rpv3(+ plants.

  15. RNA synthesis by the brome mosaic virus RNA-dependent RNA polymerase in human cells reveals requirements for de novo initiation and protein-protein interaction.

    Science.gov (United States)

    Subba-Reddy, Chennareddy V; Tragesser, Brady; Xu, Zhili; Stein, Barry; Ranjith-Kumar, C T; Kao, C Cheng

    2012-04-01

    Brome mosaic virus (BMV) is a model positive-strand RNA virus whose replication has been studied in a number of surrogate hosts. In transiently transfected human cells, the BMV polymerase 2a activated signaling by the innate immune receptor RIG-I, which recognizes de novo-initiated non-self-RNAs. Active-site mutations in 2a abolished RIG-I activation, and coexpression of the BMV 1a protein stimulated 2a activity. Mutations previously shown to abolish 1a and 2a interaction prevented the 1a-dependent enhancement of 2a activity. New insights into 1a-2a interaction include the findings that helicase active site of 1a is required to enhance 2a polymerase activity and that negatively charged amino acid residues between positions 110 and 120 of 2a contribute to interaction with the 1a helicase-like domain but not to the intrinsic polymerase activity. Confocal fluorescence microscopy revealed that the BMV 1a and 2a colocalized to perinuclear region in human cells. However, no perinuclear spherule-like structures were detected in human cells by immunoelectron microscopy. Sequencing of the RNAs coimmunoprecipitated with RIG-I revealed that the 2a-synthesized short RNAs are derived from the message used to translate 2a. That is, 2a exhibits a strong cis preference for BMV RNA2. Strikingly, the 2a RNA products had initiation sequences (5'-GUAAA-3') identical to those from the 5' sequence of the BMV genomic RNA2 and RNA3. These results show that the BMV 2a polymerase does not require other BMV proteins to initiate RNA synthesis but that the 1a helicase domain, and likely helicase activity, can affect RNA synthesis by 2a.

  16. An amphipathic alpha-helix controls multiple roles of brome mosaic virus protein 1a in RNA replication complex assembly and function.

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    Ling Liu

    2009-03-01

    Full Text Available Brome mosaic virus (BMV protein 1a has multiple key roles in viral RNA replication. 1a localizes to perinuclear endoplasmic reticulum (ER membranes as a peripheral membrane protein, induces ER membrane invaginations in which RNA replication complexes form, and recruits and stabilizes BMV 2a polymerase (2a(Pol and RNA replication templates at these sites to establish active replication complexes. During replication, 1a provides RNA capping, NTPase and possibly RNA helicase functions. Here we identify in BMV 1a an amphipathic alpha-helix, helix A, and use NMR analysis to define its structure and propensity to insert in hydrophobic membrane-mimicking micelles. We show that helix A is essential for efficient 1a-ER membrane association and normal perinuclear ER localization, and that deletion or mutation of helix A abolishes RNA replication. Strikingly, mutations in helix A give rise to two dramatically opposite 1a function phenotypes, implying that helix A acts as a molecular switch regulating the intricate balance between separable 1a functions. One class of helix A deletions and amino acid substitutions markedly inhibits 1a-membrane association and abolishes ER membrane invagination, viral RNA template recruitment, and replication, but doubles the 1a-mediated increase in 2a(Pol accumulation. The second class of helix A mutations not only maintains efficient 1a-membrane association but also amplifies the number of 1a-induced membrane invaginations 5- to 8-fold and enhances viral RNA template recruitment, while failing to stimulate 2a(Pol accumulation. The results provide new insights into the pathways of RNA replication complex assembly and show that helix A is critical for assembly and function of the viral RNA replication complex, including its central role in targeting replication components and controlling modes of 1a action.

  17. Molecular detection of Peronospora variabilis in quinoa seed and phylogeny of the quinoa downy mildew pathogen in South America and the United States.

    Science.gov (United States)

    Testen, Anna L; del Mar Jiménez-Gasco, María; Ochoa, José B; Backman, Paul A

    2014-04-01

    Quinoa (Chenopodium quinoa) is an important export of the Andean region, and its key disease is quinoa downy mildew, caused by Peronospora variabilis. P. variabilis oospores can be seedborne and rapid methods to detect seedborne P. variabilis have not been developed. In this research, a polymerase chain reaction (PCR)-based detection method was developed to detect seedborne P. variabilis and a sequencing-based method was used to validate the PCR-based method. P. variabilis was detected in 31 of 33 quinoa seed lots using the PCR-based method and in 32 of 33 quinoa seed lots using the sequencing-based method. Thirty-one of the quinoa seed lots tested in this study were sold for human consumption, with seed originating from six different countries. Internal transcribed spacer (ITS) and cytochrome c oxidase subunit 2 (COX2) phylogenies were examined to determine whether geographical differences occurred in P. variabilis populations originating from Ecuador, Bolivia, and the United States. No geographical differences were observed in the ITS-derived phylogeny but the COX2 phylogeny indicated that geographical differences existed between U.S. and South American samples. Both ITS and COX2 phylogenies supported the existence of a Peronospora sp., distinct from P. variabilis, that causes systemic-like downy mildew symptoms on quinoa in Ecuador. The results of these studies allow for a better understanding of P. variabilis populations in South America and identified a new causal agent for quinoa downy mildew. The PCR-based seed detection method allows for the development of P. variabilis-free quinoa seed, which may prove important for management of quinoa downy mildew.

  18. Identification and characterization of potential NBS-encoding resistance genes and induction kinetics of a putative candidate gene associated with downy mildew resistance in Cucumis

    Directory of Open Access Journals (Sweden)

    Wan Hongjian

    2010-08-01

    Full Text Available Abstract Background Due to the variation and mutation of the races of Pseudoperonospora cubensis, downy mildew has in recent years become the most devastating leaf disease of cucumber worldwide. Novel resistance to downy mildew has been identified in the wild Cucumis species, C. hystrix Chakr. After the successful hybridization between C. hystrix and cultivated cucumber (C. sativus L., an introgression line (IL5211S was identified as highly resistant to downy mildew. Nucleotide-binding site and leucine-rich repeat (NBS-LRR genes are the largest class of disease resistance genes cloned from plant with highly conserved domains, which can be used to facilitate the isolation of candidate genes associated with downy mildew resistance in IL5211S. Results Degenerate primers that were designed based on the conserved motifs in the NBS domain of resistance (R proteins were used to isolate NBS-type sequences from IL5211S. A total of 28 sequences were identified and named as cucumber (C. sativus = CS resistance gene analogs as CSRGAs. Polygenetic analyses separated these sequences into four different classes. Quantitative real-time polymerase chain reaction (qRT-PCR analysis showed that these CSRGAs expressed at different levels in leaves, roots, and stems. In addition, introgression from C. hystrix induced expression of the partial CSRGAs in cultivated cucumber, especially CSRGA23, increased four-fold when compared to the backcross parent CC3. Furthermore, the expression of CSRGA23 under P. cubensis infection and abiotic stresses was also analyzed at different time points. Results showed that the P. cubensis treatment and four tested abiotic stimuli, MeJA, SA, ABA, and H2O2, triggered a significant induction of CSRGA23 within 72 h of inoculation. The results indicate that CSRGA23 may play a critical role in protecting cucumber against P. cubensis through a signaling the pathway triggered by these molecules. Conclusions Four classes of NBS-type RGAs were

  19. Differential recognition of highly divergent downy mildew avirulence gene alleles by RPP1 resistance genes from two Arabidopsis lines.

    Science.gov (United States)

    Rehmany, Anne P; Gordon, Anna; Rose, Laura E; Allen, Rebecca L; Armstrong, Miles R; Whisson, Stephen C; Kamoun, Sophien; Tyler, Brett M; Birch, Paul R J; Beynon, Jim L

    2005-06-01

    The perception of downy mildew avirulence (Arabidopsis thaliana Recognized [ATR]) gene products by matching Arabidopsis thaliana resistance (Recognition of Peronospora parasitica [RPP]) gene products triggers localized cell death (a hypersensitive response) in the host plant, and this inhibits pathogen development. The oomycete pathogen, therefore, is under selection pressure to alter the form of these gene products to prevent detection. That the pathogen maintains these genes indicates that they play a positive role in pathogen survival. Despite significant progress in cloning plant RPP genes and characterizing essential plant components of resistance signaling pathways, little progress has been made in identifying the oomycete molecules that trigger them. Concluding a map-based cloning effort, we have identified an avirulence gene, ATR1NdWsB, that is detected by RPP1 from the Arabidopsis accession Niederzenz in the cytoplasm of host plant cells. We report the cloning of six highly divergent alleles of ATR1NdWsB from eight downy mildew isolates and demonstrate that the ATR1NdWsB alleles are differentially recognized by RPP1 genes from two Arabidopsis accessions (Niederzenz and Wassilewskija). RPP1-Nd recognizes a single allele of ATR1NdWsB; RPP1-WsB also detects this allele plus three additional alleles with divergent sequences. The Emco5 isolate expresses an allele of ATR1NdWsB that is recognized by RPP1-WsB, but the isolate evades detection in planta. Although the Cala2 isolate is recognized by RPP1-WsA, the ATR1NdWsB allele from Cala2 is not, demonstrating that RPP1-WsA detects a novel ATR gene product. Cloning of ATR1NdWsB has highlighted the presence of a highly conserved novel amino acid motif in avirulence proteins from three different oomycetes. The presence of the motif in additional secreted proteins from plant pathogenic oomycetes and its similarity to a host-targeting signal from malaria parasites suggest a conserved role in pathogenicity.

  20. Nitrogen balance in lambs fed low-quality brome hay and infused with differing proportions of casein in the rumen and abomasum.

    Science.gov (United States)

    Swanson, K C; Freetly, H C; Ferrell, C L

    2004-02-01

    Twenty wether lambs (46 +/- 2 kg) fitted with ruminal and abomasal infusion catheters were used in a completely randomized design to determine the effects of differing proportions of ruminal and abomasal casein infusion on N balance in lambs fed low-quality brome hay (0.8% N, DM basis) for ad libitum intake. Wethers were infused with 0 (control) or 10.7 g/d of N from casein with ratios of ruminal:abomasal infusion of 100:0 (100R:0A), 67:33 (67R:33A), 33:67 (33R:67A), or 0:100% (0R:100A), respectively, over a 12-d period. Total N supply (hay N intake + N from casein infusion) was greater (P = 0.001) in lambs receiving casein infusion than in controls. Urinary N excretion (g/d) was greater (P = 0.001) in lambs receiving casein infusion than in controls. Urinary N excretion decreased as casein infusion was shifted from 100R:0A to 33R:67A and then slightly increased in lambs receiving 0R:100A (quadratic, P = 0.02). Total N excretion was greater (P = 0.001) in lambs receiving casein infusion than in controls and decreased linearly (P = 0.005) as casein infusion was shifted to the abomasum. Retained N (g/d, % of N intake, and % of digested N) was greater (P = 0.001) in lambs receiving casein than in controls. Retained N increased as infusion was shifted from 100R:0A to 33R:67A and then slightly decreased in lambs receiving 0R: 100A (quadratic, P infusion to maximize N retention was 68% into the abomasum. The regression suggests that supplementation with undegradable intake protein had an additional benefit over supplementation with ruminally degradable intake protein (100R:0A) and that changing the percentage of ruminally undegradable intake protein in supplemental protein from 33 to 100% resulted in minimal differences in N retention. Apparent N, DM, OM, and energy digestibility (% of intake) was greater (P infused with casein than controls but did not differ among casein infusion groups. These data suggest that feeding protein supplements containing a portion (greater

  1. Winter annual cover crop has only minor effects on major corn arthropod pests.

    Science.gov (United States)

    Davis, Holly N; Currie, Randall S; Klocke, Norman L; Buschman, Lawrent L

    2010-04-01

    We studied the effects of downy brome, Bromus tectorum L., winter cover crop on several corn, Zea mays L., pests in the summer crop after the cover crop. An experiment was conducted that consisted of two trials with two levels of irrigation, two levels of weed control, and two levels of downy brome. Corn was grown three consecutive years after the downy brome grown during the winter. Banks grass mites, Oligonychus pratensis (Banks), twospotted spider mites, Tetranychus urticae Koch, and predatory mites from the genus Neoseiulus were present in downy brome at the beginning of the growing season. They moved into corn, but their numbers did not differ significantly across the treatments. Larval western corn rootworm, Diabrotica virgifera virgifera LeConte, feeding on corn roots was evaluated the second and third years of corn, production. Irrigation and herbicide treatments had no significant effects on rootworm injury levels. In one trial, rootworm injury ratings were significantly greater in treatments with a history of high versus low brome, but this effect was not significant in the other trial. Rootworm injury seemed to be similar across plots with different surface soil moistures. This suggests that the use of a winter cover crop such as downy brome will not have a major negative impact the arthropods studied.

  2. Identification of downy mildew resistance gene candidates by positional cloning in maize (Zea mays subsp. mays; Poaceae)1

    Science.gov (United States)

    Kim, Jae Yoon; Moon, Jun-Cheol; Kim, Hyo Chul; Shin, Seungho; Song, Kitae; Kim, Kyung-Hee; Lee, Byung-Moo

    2017-01-01

    Premise of the study: Positional cloning in combination with phenotyping is a general approach to identify disease-resistance gene candidates in plants; however, it requires several time-consuming steps including population or fine mapping. Therefore, in the present study, we suggest a new combined strategy to improve the identification of disease-resistance gene candidates. Methods and Results: Downy mildew (DM)–resistant maize was selected from five cultivars using a spreader row technique. Positional cloning and bioinformatics tools were used to identify the DM-resistance quantitative trait locus marker (bnlg1702) and 47 protein-coding gene annotations. Eventually, five DM-resistance gene candidates, including bZIP34, Bak1, and Ppr, were identified by quantitative reverse-transcription PCR (RT-PCR) without fine mapping of the bnlg1702 locus. Conclusions: The combined protocol with the spreader row technique, quantitative trait locus positional cloning, and quantitative RT-PCR was effective for identifying DM-resistance candidate genes. This cloning approach may be applied to other whole-genome-sequenced crops or resistance to other diseases. PMID:28224059

  3. Antisporulant Activity of Watery Extracts of Plants against Sclerospora graminicola Causing Downy Mildew Disease of Pearl Millet

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    S. A. Deepak

    2007-01-01

    Full Text Available Watery extracts of forty plant species commonly growing in across India have been screened for antisporulant activity against Sclerospora graminicola (Sacc. Schroet., the causative agent of pearl millet downy mildew. The collection represented 38 genera of 30 families. The extracts of thirteen species did not show any effect, whereas the activity of extracts of Allium sativum, Clematis gouriana, Evolvulus alsinoides, Mimusops elengi, Parthenium hysterophorus, Piper nigrum and Tagetes erecta were commensurable to that of marketed botanical fungicides and Mikal 70 wp. The crude extracts of 12 species (Agave americana, Aloe vera, Artemisia parviflora, Citrus limon, Citrus sinensis, Eucalyptus globosus, Euphorbia hirta, Leucas aspera, Murraya koenigi, Ocimum sanctum, Santalum album and Zingiber offinale completely inhibited the zoosprorangium formation while in the case of remaining 8 plants the crude extracts reduced only partially the sporulation. The antisporulant activity of commercialised Azadirachta preparation (Nutri-Neem was more pronounced than that of Reynutria based one (Milsana and Sabadilla (veratrin, however, these botanical preparations held off synthetic fungicides and the most active watery extracts.

  4. Lactuca saligna, a non-host for lettuce downy mildew ( Bremia lactucae), harbors a new race-specific Dm gene and three QTLs for resistance.

    Science.gov (United States)

    Jeuken, M.; Lindhout, P.

    2002-08-01

    Lactuca sativa (lettuce) is susceptible to Bremia lactucae (downy mildew). In cultivated and wild Lactuca species, Dm genes have been identified that confer race-specific resistance. However, these genes were soon rendered ineffective by adaptation of the pathogen. Lactuca saligna (wild lettuce) is resistant to all downy mildew races and can be considered as a non-host. Therefore, L. saligna might be an alternative source for a more-durable resistance to downy mildew in lettuce. In order to analyze this resistance, we have developed an F(2) population based on a resistant L. saligna x susceptible L. sativa cross. This F(2) population was fingerprinted with AFLP markers and tested for resistance to two Bremia races NL14 and NL16. The F(2) population showed a wide and continuous range of resistance levels from completely resistant to completely susceptible. By comparison of disease tests, we observed a quantitative resistance against both Bremia races as well as a race-specific resistance to Bremia race NL16 and not to NL14. QTL mapping revealed a qualitative gene ( R39) involved in the race-specific resistance and three QTLs ( RBQ1, RBQ2 and RBQ3) involved in the quantitative resistance. The qualitative gene R39 is a dominant gene that gives nearly complete resistance to race NL16 in L. saligna CGN 5271 and therefore it showed features similar to Dm genes. The three QTLs explained 51% of the quantitative resistance against NL14, which indicated that probably only the major QTLs have been detected in this F(2) population. The perspectives for breeding for durable resistance are discussed.

  5. Molecular cloning of a coiled-coil-nucleotide-binding-site-leucine-rich repeat gene from pearl millet and its expression pattern in response to the downy mildew pathogen.

    Science.gov (United States)

    Veena, Mariswamy; Melvin, Prasad; Prabhu, Sreedhara Ashok; Shailasree, Sekhar; Shetty, Hunthrike Shekar; Kini, Kukkundoor Ramachandra

    2016-03-01

    Downy mildew caused by Sclerospora graminicola is a devastating disease of pearl millet. Based on candidate gene approach, a set of 22 resistance gene analogues were identified. The clone RGPM 301 (AY117410) containing a partial sequence shared 83% similarity to rice R-proteins. A full-length R-gene RGA RGPM 301 of 3552 bp with 2979 bp open reading frame encoding 992 amino acids was isolated by the degenerate primers and rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR) approach. It had a molecular mass of 113.96 kDa and isoelectric point (pI) of 8.71. The sequence alignment and phylogenetic analysis grouped it to a non-TIR NBS LRR group. The quantitative real-time PCR (qRT-PCR) analysis revealed higher accumulation of the transcripts following inoculation with S. graminicola in the resistant cultivar (IP18296) compared to susceptible cultivar (7042S). Further, significant induction in the transcript levels were observed when treated with abiotic elicitor β-aminobutyric acid (BABA) and biotic elicitor Pseudomonas fluorescens. Exogenous application of phytohormones jasmonic acid or salicylic acid also up-regulated the expression levels of RGA RGPM 301. The treatment of cultivar IP18296 with mitogen-activated protein kinase (MPK) inhibitors (PD98059 and U0126) suppressed the levels of RGA RGPM 301. A 3.5 kb RGA RGPM 301 which is a non-TIR NBS-LRR protein was isolated from pearl millet and its up-regulation during downy mildew interaction was demonstrated by qRT-PCR. These studies indicate a role for this RGA in pearl millet downy mildew interaction.

  6. Identification and introgression of QTLs implicated in resistance to sorghum downy mildew (Peronosclerospora sorghi (Weston and Uppal) C. G. Shaw) in maize through marker-assisted selection

    Indian Academy of Sciences (India)

    H. C. Lohithaswa; K. Jyothi; K. R. Sunil Kumar; Puttaramanaik; Shailaja Hittalmani

    2015-12-01

    Sorghum downy mildew caused by Peronosclerospora sorghi is a major disease of maize and resistance is under the control of polygenes which necessitated identification of quantitative-trait loci (QTLs) for initiating marker-assisted introgression of resistant QTLs in elite susceptible inbred lines. In the present study, QTLs for sorghum downy mildew (SDM) resistance in maize were identified based on cosegregation with linked simple sequence repeats in 185 F2 progeny from a cross between susceptible (CM500-19) and resistant (MAI105) parents. F3 families were screened in the National Sorghum Downy Mildew Screening Nursery during 2010 and 2011. High heritability was observed for the disease reaction. The final map generated using 87 SSR markers had 10 linkage groups, spanning a length of 1210.3 cM. Although, we used only 87 SSR markers for mapping, the per cent of genome within 20 cM to the nearest marker was 88.5. Three putative QTLs for SDM resistance were located on chromosomes 3 (bin 3.01), 6 (bin 6.01) and 2 (bin 2.02) using composite interval mapping. The locus on chromosome 3 had a major effect and explained up to 12.6% of the phenotypic variation. The other two QTLs on chromosomes 6 and 2 had minor effects with phenotypic variation of 7.1 and 2%. The three QTLs appeared to have additive effects on resistance. The QTLs on chromosomes 3 and 6 were successfully used in the marker-assisted selection programme for introgression of resistance to SDM in eight susceptible maize lines.

  7. Exogenous Trehalose Treatment Enhances the Activities of Defense-Related Enzymes and Triggers Resistance against Downy Mildew Disease of Pearl Millet

    Science.gov (United States)

    Govind, Sharathchandra R.; Jogaiah, Sudisha; Abdelrahman, Mostafa; Shetty, Hunthrike S.; Tran, Lam-Son P.

    2016-01-01

    In recent years, diverse physiological functions of various sugars are the subject of investigations. Their roles in signal transduction in plant responses to adverse biotic and abiotic stress conditions have become apparent, and growing scientific evidence has indicated that disaccharides like sucrose and trehalose mediate plant defense responses in similar way as those induced by elicitors against the pathogens. Trehalose is a well-known metabolic osmoregulator, stress-protectant and non-reducing disaccharide existing in a variety of organisms, including fungi, bacteria, and plants. Commercially procured trehalose was applied to seeds of susceptible pearl millet (Pennisetum glaucum) cultivar “HB3,” and tested for its ability to reduce downy mildew disease incidence by induction of resistance. Seed treatment with trehalose at 200 mM for 9 h recorded 70.25% downy mildew disease protection, followed by those with 100 and 50 mM trehalose which offered 64.35 and 52.55% defense, respectively, under greenhouse conditions. Furthermore, under field conditions treatment with 200 mM trehalose for 9 h recorded 67.25% downy mildew disease protection, and reduced the disease severity to 32.75% when compared with untreated control which displayed 90% of disease severity. Trehalose did not affect either sporangial formation or zoospore release from sporangia, indicating that the reduction in disease incidence was not due to direct inhibition but rather through induction of resistance responses in the host. Additionally, trehalose was shown to enhance the levels of polyphenol oxidase, phenylalanine ammonia lyase, and peroxidase, which are known as markers of both biotic and abiotic stress responses. Our study shows that osmoregulators like trehalose could be used to protect plants against pathogen attacks by seed treatment, thus offering dual benefits of biotic and abiotic stress tolerance. PMID:27895647

  8. A transgenic mutant of Lactuca sativa (lettuce) with a T-DNA tightly linked to loss of downy mildew resistance.

    Science.gov (United States)

    Okubara, P A; Arroyo-Garcia, R; Shen, K A; Mazier, M; Meyers, B C; Ochoa, O E; Kim, S; Yang, C H; Michelmore, R W

    1997-11-01

    One hundred and ninety-two independent primary transformants of lettuce cv. Diana were obtained by co-cultivation with Agrobacterium tumefaciens carrying constructs containing maize Ac transposase and Ds. R2 families were screened for mutations at four genes (Dm) for resistance to downy mildew. One family, designated dm3t524, had lost resistance to an isolate of Bremia lactucae expressing the avirulence gene Avr3. Loss of resistance segregated as a single recessive allele of Dm3. The mutation was not due to a large deletion as all molecular markers flanking Dm3 were present. Loss of Dm3 activity co-segregated with a T-DNA from which Ds had excised. Genomic DNA flanking the right border of this T-DNA was isolated by inverse polymerase chain reaction. This genomic sequence was present in four to five copies in wild-type cv. Diana. One copy was missing in all eight deletion mutants of Dm3 and altered in dm3t524, indicating tight physical linkage to Dm3. Three open reading frames (ORFs) occurred in a 6.6-kb region flanking the insertion site; however, expression of these ORFs was not detected. No similarities were detected between these ORFs and resistance genes cloned from other species. Transgenic complementation with 11-to 27-kb genomic fragments of Diana spanning the insertion site failed to restore Dm3 function to two ethyl methanesulfonate (EMS)-induced mutants of Dm3 or to cv. Cobham Green, which naturally lacks Dm3 activity. Therefore, either the T-DNA inserted extremely close to, but not within, Dm3 and the mutation may have been caused by secondary movement of Ds, or Dm3 activity is encoded by a gene extending beyond the fragments used for complementation.

  9. Preliminary Trial of 11 New Hybrid Maize Genotype to The Resistance on Java Downy Mildew (Peronosclerospora maydis

    Directory of Open Access Journals (Sweden)

    Budi Setyawan

    2016-04-01

    Full Text Available Maize or corn (Zea mays L. belongs to the family of grasses (Poaceae.  Maize is grown globally and one of the most important cereal crop in the world.  In many countries, corn is the main agricultural crop, and are used as food, feed and industrial raw materials. Together with rice and wheat, corn included in the cereals that provide about 65% carbohydrates and 50% protein that humans need. For this purpose, many developing countries, especially in Asia and Africa are in a strong effort to increase their corn yields through the use of better seeds.  Although in Indonesia, corn is the second important food crop after rice, however, with the rapid growth of the livestock industry, corn is a major component (60% in feed ingredient.  It is estimated that more than 55% of the corn used for feed in Indonesia.  Java Downy Mildew (Peronosclerospora maydis is the main disease that is concerned by maize corn growers. This disease often resulting in substantial losses for farmers, even reach 100% in susceptible genotypes.  Therefore trial on 11 new prospective hybrids was conducted with the expectation that they can be classified in the criteria “less resistant or higher” according to the criteria of modified Reid (2005.  Of the 11 new hybrids, 3 new hybrids (27.3% classified in the criteria “very resistant”, 4 new hybrids (36.4% classified in the criteria “resistant”, 2 new hybrid (18.2% classified in the criteria “less resistant”, and 2 other new hybrids (18.2% classified in the criteria “less susceptible”.

  10. Over-expression of VvWRKY1 in grapevines induces expression of jasmonic acid pathway-related genes and confers higher tolerance to the downy mildew.

    Directory of Open Access Journals (Sweden)

    Chloé Marchive

    Full Text Available Most WRKY transcription factors activate expression of defence genes in a salicylic acid- and/or jasmonic acid-dependent signalling pathway. We previously identified a WRKY gene, VvWRKY1, which is able to enhance tolerance to fungal pathogens when it is overexpressed in tobacco. The present work analyzes the effects of VvWRKY1 overexpression in grapevine. Microarray analysis showed that genes encoding defence-related proteins were up-regulated in the leaves of transgenic 35S::VvWRKY1 grapevines. Quantitative RT-PCR analysis confirmed that three genes putatively involved in jasmonic acid signalling pathway were overexpressed in the transgenic grapes. The ability of VvWRKY1 to trans-activate the promoters of these genes was demonstrated by transient expression in grape protoplasts. The resistance to the causal agent of downy mildew, Plasmopara viticola, was enhanced in the transgenic plants. These results show that VvWRKY1 can increase resistance of grapevine against the downy mildew through transcriptional reprogramming leading to activation of the jasmonic acid signalling pathway.

  11. Specific in planta recognition of two GKLR proteins of the downy mildew Bremia lactucae revealed in a large effector screen in lettuce.

    Science.gov (United States)

    Stassen, Joost H M; den Boer, Erik; Vergeer, Pim W J; Andel, Annemiek; Ellendorff, Ursula; Pelgrom, Koen; Pel, Mathieu; Schut, Johan; Zonneveld, Olaf; Jeuken, Marieke J W; Van den Ackerveken, Guido

    2013-11-01

    Breeding lettuce (Lactuca sativa) for resistance to the downy mildew pathogen Bremia lactucae is mainly achieved by introgression of dominant downy mildew resistance (Dm) genes. New Bremia races quickly render Dm genes ineffective, possibly by mutation of recognized host-translocated effectors or by suppression of effector-triggered immunity. We have previously identified 34 potential RXLR(-like) effector proteins of B. lactucae that were here tested for specific recognition within a collection of 129 B. lactucae-resistant Lactuca lines. Two effectors triggered a hypersensitive response: BLG01 in 52 lines, predominantly L. saligna, and BLG03 in two L. sativa lines containing Dm2 resistance. The N-terminal sequences of BLG01 and BLG03, containing the signal peptide and GKLR variant of the RXLR translocation motif, are not required for in planta recognition but function in effector delivery. The locus responsible for BLG01 recognition maps to the bottom of lettuce chromosome 9, whereas recognition of BLG03 maps in the RGC2 cluster on chromosome 2. Lactuca lines that recognize the BLG effectors are not resistant to Bremia isolate Bl:24 that expresses both BLG genes, suggesting that Bl:24 can suppress the triggered immune responses. In contrast, lettuce segregants displaying Dm2-mediated resistance to Bremia isolate Bl:5 are responsive to BLG03, suggesting that BLG03 is a candidate Avr2 protein.

  12. Analyzing Lettuce Downy Mildew with Fourier Transform Infrared Spectroscopy%莴苣霜霉病的傅里叶变换红外光谱分析

    Institute of Scientific and Technical Information of China (English)

    杨春艳; 刘飞; 梁云峰; 吉恒

    2014-01-01

    Fourier transform infrared spectroscopy (FTIR) was used to obtain the spectra of leaf, edible stem, taproot and fibrous roots of normal and downy mildew lettuce plants at the adult stage. The results showed that for normal and downy mildew lettuce plants, the main components of leaves and edible stem were protein, carbohydrates and lipids. For fibrous roots, the main components were cellulose and lignin. For taproots of normal plants,the main components were cellulose, lignin and lipids, but cellulose, lignin and protein were the main components of downy mildew plants. Relative to normal plants,the structure of carbohydrates and protein in leaves was changed. The relative content of lipids and carbohydrates increased. Protein and lipids in edible stems was decreased while carbohydrates was increased. Cellulose and lignin in taproot and fibrous roots were decreased. The ratio of the relative content of lignin to that of cellulose in mildew plants was higher than that in normal plants. It is indicated that FTIR could be used to study effects of the downy mildew on different parts of the lettuce, providing spectroscopy information for studying lettuce downy mildew.%利用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)技术测定了成株期莴苣(Lactuca sativa L.var.angustana Irish)正常植株和霜霉病植株的叶片、食用茎、主根和须根4个部位的红外光谱。结果表明,两种植株叶片和食用茎中的主要成分均为蛋白质、多糖和脂类物质,须根中的主要物质成分为纤维素和木质素,正常植株主根中的主要成分是纤维素、木质素和脂类物质,霜霉病主根中的主要成分是纤维素、木质素和蛋白质;与正常植株相比,霜霉病植株叶片中蛋白质和多糖的组成或结构发生了变化,且脂类和多糖类物质相对含量有所增加,食用茎中蛋白质和脂类物质的相对含量均低于正常植株,而多糖类物质相对

  13. Detection of Verticillium wilt of olive trees and downy mildew of opium poppy using hyperspectral and thermal UAV imagery

    Science.gov (United States)

    Calderón Madrid, Rocío; Navas Cortés, Juan Antonio; Montes Borrego, Miguel; Landa del Castillo, Blanca Beatriz; Lucena León, Carlos; Jesús Zarco Tejada, Pablo

    2014-05-01

    The present study explored the use of high-resolution thermal, multispectral and hyperspectral imagery as indicators of the infections caused by Verticillium wilt (VW) in olive trees and downy mildew (DM) in opium poppy fields. VW, caused by the soil-borne fungus Verticillium dahliae, and DM, caused by the biotrophic obligate oomycete Peronospora arborescens, are the most economically limiting diseases of olive trees and opium poppy, respectively, worldwide. V. dahliae infects the plant by the roots and colonizes its vascular system, blocking water flow and eventually inducing water stress. P. arborescens colonizes the mesophyll, appearing the first symptoms as small chlorotic leaf lesions, which can evolve to curled and thickened tissues and systemic infections that become deformed and necrotic as the disease develops. The work conducted to detect VW and DM infection consisted on the acquisition of time series of airborne thermal, multispectral and hyperspectral imagery using 2-m and 5-m wingspan electric Unmanned Aerial Vehicles (UAVs) in spring and summer of three consecutive years (2009 to 2011) for VW detection and on three dates in spring of 2009 for DM detection. Two 7-ha commercial olive orchards naturally infected with V. dahliae and two opium poppy field plots artificially infected by P. arborescens were flown. Concurrently to the airborne campaigns, olive orchards and opium poppy fields were assessed "in situ" to assess actual VW severity and DM incidence. Furthermore, field measurements were conducted at leaf and crown level. The field results related to VW detection showed a significant increase in crown temperature (Tc) minus air temperature (Ta) and a decrease in leaf stomatal conductance (G) as VW severity increased. This reduction in G was associated with a significant increase in the Photochemical Reflectance Index (PRI570) and a decrease in chlorophyll fluorescence. DM asymptomatic leaves showed significantly higher NDVI and lower green/red index

  14. Incidence of downy mildew Plasmopara viticola (Berk. et Curtis ex. de Bary Berl. et de Toni in Terceira island, Azores

    Directory of Open Access Journals (Sweden)

    Matej Zorman

    2008-12-01

    Full Text Available Downy mildew is one of the most economically important disease affecting vine production in Terceira island, Azores. By its incidence, frequency and quantity of pathogens, supported with favourable temperate humid climate conditions, this disease is difficult to control in terms of sustainable integrated plant protection policy. The objectives of INTERFRUTA project were to determine the incidence of the disease, to better understand it and to adopt an adequate forecasting model with necessary adjustments to predict the disease appearance and its in-time integrated plant protection control measures. Plasmopara viticola was directly observed in two weeks time periods on seven representative vineyards at different altitudes. Three of the monitored plots were established during study inside one plantation. Incidence was registered as result of visual symptoms in percentage, where 10% of plants in each vineyard were observed. Seasonal evolution of the disease was studied in one of the wine producing area.O Míldio é uma das doenças que mais afecta a vinha, na ilha Terceira, Açores. É uma doença fúngica de difícil controlo, pela sua incidência e frequência de aparecimento. Os objectivos do projecto INTERFRUTA II foram determinar a incidência desta doença para melhorar o conhecimento sobre esta e adoptar e validar um modelo matemático adequado à previsão do aparecimento da doença de modo a permitir a aplicação de medidas de protecção integrada. A evolução do míldio foi acompanhada em sete parcelas de vinha, da área vitivinícola dos Biscoitos, através da observação visual de folhas. Numa das parcelas, três dos talhões não foram tratados para servirem de controlo. Em cada parcela foram observadas 10% das plantas, tendo sido registada a percentagem de plantas com sintomas visuais da presença de míldio.

  15. Proteome of Plasmopara viticola-infected Vitis vinifera provides insights into grapevine Rpv1/Rpv3 pyramided resistance to downy mildew.

    Science.gov (United States)

    Nascimento-Gavioli, Maria Carolina Andrade; Agapito-Tenfen, Sarah Zanon; Nodari, Rubens Onofre; Welter, Leocir José; Sanchez Mora, Fernando David; Saifert, Luciano; da Silva, Aparecido Lima; Guerra, Miguel Pedro

    2017-01-16

    Grapevine is one of the major fruit crops worldwide and requires phytochemical use due to susceptibility to numerous pests, including downy mildew. The pyramiding of previous identified QTL resistance regions allows selection of genotypes with combined resistance loci in order to build up sustainable resistance. This study investigates resistance response of pyramided plants containing Rpv1 and Rpv3 loci to Plasmopara viticola infection process. Phenotypic characterization showed complete resistance and lack of necrotic hypersensitive response spots. Principal Component Analysis revealed infected 96hpi (hours post-inoculation) samples with the most distant proteomes of the entire dataset, followed by the proteome of infected 48hpi samples. Quantitative and qualitative protein differences observed using 2-DE gels coupled to nanoHPLC-ESI-MS/MS analysis showed a lack of transient breakdown in defense responses (biphasic modulation) accompanying the onset of disease. Forty-one proteins were identified, which were mainly included into functional categories of redox and energy metabolism. l-ascorbate degradation pathway was the major altered pathway and suggests up-regulation of anti-oxidant metabolism in response to apoplastic oxidative burst after infection. Overall, these data provide new insights into molecular basis of this incompatible interaction and suggests several targets that could potentially be exploited to develop new protection strategies against this pathogen. This study provide new insights into the molecular basis of incompatible interaction between Plasmopara viticola and pyramided Rpv1/Rpv3 grapevine and suggests several targets that could potentially be exploited to develop new protection strategies against this pathogen. This is the first proteomic characterization of resistant grapevine available in the literature and it presents contrasting proteomic profiles of that of susceptible plants. The resistance against downy mildew in grapevine has been

  16. Genomic plus-strand RNA synthesis by the brome mosaic virus (BMV) RNA replicase requires a sequence that is complementary to the binding site of the BMV helicase-like protein.

    Science.gov (United States)

    Sivakumaran, K; Kao, C C

    2000-11-01

    Summary Initiation of genomic plus-strand RNA synthesis by the brome mosaic virus (BMV) replicase in vitro requires a 26-nucleotide (nt) RNA sequence at the 3' end of the minus-strand RNA and a nontemplated nucleotide 3' of the initiation cytidylate [Sivakumaran, K. and Kao, C.C. (1999)J. Virol.64, 6415-6423]. At the 5' end of this RNA is a 9-nt sequence called the cB box, the complement of the previously defined B box. The cB box can not be functionally replaced by the B box and has specific positional and sequence requirements. The portion of the cB box that is required for RNA synthesis in vitro is well-conserved in species in the Bromoviridae family. An equivalent RNA from Cucumber mosaic virus was unable to direct efficient RNA synthesis by the BMV replicase until the cB box was positioned at the same site relative to the BMV RNA and guanylates were present at positions +6 and +7 from the initiation cytidylate. These results further define the elements required for the recognition and initiation of viral genomic plus-strand RNA synthesis and suggest that a sequence important for minus-strand RNA synthesis is also required for plus-strand RNA synthesis.

  17. Study on Fungicide Screening for Un -pollutive Control of Grape Downy Mildew and Its Control Techniques%葡萄霜霉病无公害防治药剂筛选及控害技术研究

    Institute of Scientific and Technical Information of China (English)

    周步海; 李红阳; 陈志谊; 周加春; 杨华; 张俊喜

    2011-01-01

    The control effects of 6 commonly - used effective fungicide varieties (Dimethomorph, Azoxystrobin and so on) against grape downy mildew in the field were tested. The results indicated that Dimethomorph, Azoxystrobin and Propineb had better prevention and control effects on the occurrence of grape downy mildew. The other 3 kinds of fungicides could be used as the alternative fungicides in order to delay the resistance of its pathogen to the fungicides. Simultaneously, according to the occurrence characteristics of grape downy mildew, the integrated prevention and control techniques of this disease were put forward.%选取烯酰吗啉、阿米西达等6种对葡萄霜霉病有效的常用杀菌剂品种进行田间试验,结果表明:阿米西达、丙森锌2种药剂对预防和控制霜霉病的发生有较好的效果,可推荐使用;另外4种药剂可在控害过程中作为轮换药剂,与其他农药搭配使用,以延缓病原菌抗药性的产生.同时针对病害发生特点对其综合防控技术进行了研究集成.

  18. Disentangling Peronospora on Papaver: phylogenetics, taxonomy, nomenclature and host range of downy mildew of opium poppy (Papaver somniferum and related species.

    Directory of Open Access Journals (Sweden)

    Hermann Voglmayr

    Full Text Available Based on sequence data from ITS rDNA, cox1 and cox2, six Peronospora species are recognised as phylogenetically distinct on various Papaver species. The host ranges of the four already described species P. arborescens, P. argemones, P. cristata and P. meconopsidis are clarified. Based on sequence data and morphology, two new species, P. apula and P. somniferi, are described from Papaver apulum and P. somniferum, respectively. The second Peronospora species parasitizing Papaver somniferum, that was only recently recorded as Peronospora cristata from Tasmania, is shown to represent a distinct taxon, P. meconopsidis, originally described from Meconopsis cambrica. It is shown that P. meconopsidis on Papaver somniferum is also present and widespread in Europe and Asia, but has been overlooked due to confusion with P. somniferi and due to less prominent, localized disease symptoms. Oospores are reported for the first time for P. meconopsidis from Asian collections on Papaver somniferum. Morphological descriptions, illustrations and a key are provided for all described Peronospora species on Papaver. cox1 and cox2 sequence data are confirmed as equally good barcoding loci for reliable Peronospora species identification, whereas ITS rDNA does sometimes not resolve species boundaries. Molecular phylogenetic data reveal high host specificity of Peronospora on Papaver, which has the important phytopathological implication that wild Papaver spp. cannot play any role as primary inoculum source for downy mildew epidemics in cultivated opium poppy crops.

  19. [Chromosomal structure of the hybrids between Allium cepa L. and Allium fistulosum L. with relative resistance to downy mildew based on in situ hybridization].

    Science.gov (United States)

    Budylin, M V; Kan, L Iu; Romanov, V S; Khrustaleva, L I

    2014-04-01

    Genomic in situ hybridization (GISH) was used for a chromosomal composition study of the later generations of interspecific hybrids between A. cepa L. and A. fistulosum L., which are relatively resistant to downy mildew (peronosporosis). GISH revealed that F2 hybrids, which did not produce seeds, were triploids (2n = 3x = 24) with 24 chromosomes and possessed in their compliments 16 chromosomes of A. fistulosum L. and eight chromosomes of A. cepa L. or eight chromosomes of A. fistulosum L. and 16 chromosomes of A. cepa L. The advanced F5 hybrid, which produced few seeds, was amphidiploid with 32 chromosomes. BC1F5 hybrid was triploid with eight chromosomes of A. fistulosum L. and 16 chromosomes of A. cepa L., which did not produce seeds. BC2 (BC1F5) plant was amphidiploid that possessed 4 recombinant chromosomes and produced few seeds. GISH results point to 2n-gametes formation in macro- and microsporogenesis of the hybrids. The mechanism of 2n-gametes formation and the possibility of apomixes events in the backcrossing progeny are discussed.

  20. The Novel Oomycide Oxathiapiprolin Inhibits All Stages in the Asexual Life Cycle of Pseudoperonospora cubensis - Causal Agent of Cucurbit Downy Mildew.

    Directory of Open Access Journals (Sweden)

    Yigal Cohen

    Full Text Available Oxathiapiprolin is a new oomycide (piperidinyl thiazole isoxazoline class discovered by DuPont which controls diseases caused by oomycete plant pathogens. It binds in the oxysterol-binding protein domain of Oomycetes. Growth chambers studies with detached leaves and potted plants showed remarkable activity of oxathiapiprolin against Pseudoperonospora cubensis in cucurbits. The compound affected all stages in the asexual life cycle of the pathogen. It inhibited zoospore release, cystospore germination, lesion formation, lesion expansion, sporangiophore development and sporangial production. When applied to the foliage as a preventive spray no lesions developed due to inhibition of zoospore release and cystospore germination, and when applied curatively, at one or two days after inoculation, small restricted lesions developed but no sporulation occurred. When applied later to mature lesions, sporulation was strongly inhibited. Oxathiapiprolin suppressed sporulation of P. cubensis in naturally-infected leaves. It exhibited trans-laminar activity, translocated acropetaly from older to younger leaves, and moved from the root system to the foliage. Seed coating was highly effective in protecting the developed cucumber plants against downy mildew. UV microscopy observations made with cucumber leaves infected with P. cubensis revealed that inhibition of mycelium growth and sporulation induced by oxathiapiprolin was associated with callose encasement of the haustoria.

  1. A Puf RNA-binding protein encoding gene PlM90 regulates the sexual and asexual life stages of the litchi downy blight pathogen Peronophythora litchii.

    Science.gov (United States)

    Jiang, Liqun; Ye, Wenwu; Situ, Junjian; Chen, Yubin; Yang, Xinyu; Kong, Guanghui; Liu, Yaya; Tinashe, Runyanga J; Xi, Pinggen; Wang, Yuanchao; Jiang, Zide

    2017-01-01

    Sexual and asexual reproduction are two key processes in the pathogenic cycle of many filamentous pathogens. However in Peronophythora litchii, the causal pathogen for the litchi downy blight disease, critical regulator(s) of sexual or asexual differentiation has not been elucidated. In this study, we cloned a gene named PlM90 from P. litchii, which encodes a putative Puf RNA-binding protein. We found that PlM90 was highly expressed during asexual development, and much higher than that during sexual development, while relatively lower during cyst germination and plant infection. By polyethylene glycol (PEG)-mediated protoplast transformation, we generated three PlM90-silenced transformants and found a severely impaired ability in sexual spore production and a delay in stages of zoospore release and encystment. However, the pathogenicity of P. litchii was not affected by PlM90-silencing. Therefore we conclude that PlM90 specifically regulates the sexual and asexual differentiation of P. litchii.

  2. The Control Effect Comparison of Six Kinds of Fungicides on the Downy Mildew of Tangshan Autumn Cucumber%6种药剂对唐山秋瓜霜霉病的防治效果比较

    Institute of Scientific and Technical Information of China (English)

    吴志会; 韩晓清; 张尚卿; 彭学文

    2014-01-01

    为确定防治唐山秋瓜霜霉病的最佳药剂,以清水作对照,对6种供试药剂进行了防治效果比较试验。结果表明:6种药剂均对唐山秋瓜生长安全,且均对唐山秋瓜霜霉病具有一定的防治效果,其中,阿米西达(120 g/hm2)对唐山秋瓜霜霉病的防治效果始终在90%以上,防效最好,且药效持续时间最长;72%克露WP (540 g/hm2)和大生M-4580%WP (900 g/hm2)防效次之,对霜霉病的防治效果始终维持在80%以上。建议在生产上各供试药剂轮换交替使用,以延缓唐山秋瓜霜霉病抗药性的产生。%Taking clean water as the contrast, the control effects of six kinds of fungicides was tested to determine the best medicament to control downy mildew of Tangshan autumn cucumber.The results showed that six kinds of tested fungicides were safety to the growth of Tangshan autumn cucumber , and they all had a certain control effect on the Tangshan autumn cucumber downy mildew.Azoxystrobin (120 g/hm2) had the best control effect on the Tangshan autumn cucumber downy mildew , its control effect always above 90%, followed by 64% mancozeb 8%cymoxanil WP ( 540 g/hm2 ) and 80% mancozeb WP ( 900 g/hm2 ) , their control effect were always above 80%.It was suggested that all of the tested fungicides should be used altermately to delay the drug resistance of Tangshan autumn cucumber downy mildew in production.

  3. General and species-specific transcriptional responses to downy mildew infection in a susceptible (Vitis vinifera and a resistant (V. riparia grapevine species

    Directory of Open Access Journals (Sweden)

    Lovato Arianna

    2010-02-01

    Full Text Available Abstract Background Downy mildew is a destructive grapevine disease caused by Plasmopara viticola (Berk. and Curt. Berl. and de Toni, which can only be controlled by intensive fungicide treatments. Natural sources of resistance from wild grapevine (Vitis species are used in conventional breeding approaches, but the signals and effectors involved in resistance in this important crop species are not well understood. Results Early transcriptional changes associated with P. viticola infection in susceptible V. vinifera and resistant V. riparia plants were analyzed using the Combimatrix microarray platform. Transcript levels were measured 12 and 24 h post-inoculation, reflecting the time points immediately preceding the onset of resistance in V. riparia, as determined by microscopic analysis. Our data indicate that resistance in V. riparia is induced after infection, and is not based on differences in basal gene expression between the two species. The strong and rapid transcriptional reprogramming involves the induction of pathogenesis-related proteins and enzymes required for the synthesis of phenylpropanoid-derived compounds, many of which are also induced, albeit to a lesser extent, in V. vinifera. More interestingly, resistance in V. riparia also involves the specific modulation of numerous transcripts encoding components of signal transduction cascades, hypersensitive reaction markers and genes involved in jasmonate biosynthesis. The limited transcriptional modulation in V. vinifera represents a weak attempted defense response rather than the activation of compatibility-specific pathways. Conclusions Several candidate resistance genes were identified that could be exploited in future biotechnological approaches to increase disease resistance in susceptible grapevine species. Measurements of jasmonic acid and methyl jasmonate in infected leaves suggest that this hormone may also be involved in V. riparia resistance to P. viticola.

  4. General and species-specific transcriptional responses to downy mildew infection in a susceptible (Vitis vinifera) and a resistant (V. riparia) grapevine species

    Science.gov (United States)

    2010-01-01

    Background Downy mildew is a destructive grapevine disease caused by Plasmopara viticola (Berk. and Curt.) Berl. and de Toni, which can only be controlled by intensive fungicide treatments. Natural sources of resistance from wild grapevine (Vitis) species are used in conventional breeding approaches, but the signals and effectors involved in resistance in this important crop species are not well understood. Results Early transcriptional changes associated with P. viticola infection in susceptible V. vinifera and resistant V. riparia plants were analyzed using the Combimatrix microarray platform. Transcript levels were measured 12 and 24 h post-inoculation, reflecting the time points immediately preceding the onset of resistance in V. riparia, as determined by microscopic analysis. Our data indicate that resistance in V. riparia is induced after infection, and is not based on differences in basal gene expression between the two species. The strong and rapid transcriptional reprogramming involves the induction of pathogenesis-related proteins and enzymes required for the synthesis of phenylpropanoid-derived compounds, many of which are also induced, albeit to a lesser extent, in V. vinifera. More interestingly, resistance in V. riparia also involves the specific modulation of numerous transcripts encoding components of signal transduction cascades, hypersensitive reaction markers and genes involved in jasmonate biosynthesis. The limited transcriptional modulation in V. vinifera represents a weak attempted defense response rather than the activation of compatibility-specific pathways. Conclusions Several candidate resistance genes were identified that could be exploited in future biotechnological approaches to increase disease resistance in susceptible grapevine species. Measurements of jasmonic acid and methyl jasmonate in infected leaves suggest that this hormone may also be involved in V. riparia resistance to P. viticola. PMID:20167053

  5. Ecological genetics of floret mass variation in Bromus tectorum (Poaceae)

    Science.gov (United States)

    Susan E. Meyer

    2010-01-01

    Bromus tectorum L. (cheatgrass, downy brome) is a highly invasive inbreeding annual grass that dominates millions of hectares of former shrubland in interior western North America. Factors contributing to its success include strong genetic regulation of key adaptive traits coupled with high phenotypic plasticity in response to resource availability (Meyer and Allen...

  6. Identification of Molecular Genetic Markers Tightly Linked to Downy Mildew Resistant Genes in Grape%与葡萄抗霜霉病基因紧密连锁的 分子遗传标记

    Institute of Scientific and Technical Information of China (English)

    罗素兰; 贺普超; 周鹏; 郑学勤

    2001-01-01

    Bulk segregant analysis (BSA), randomly amplified polymorphic DNA(RAPD) and sequence characterized amplified region (SCAR) methods were used to tag the downy mildew-resistant genes of grape with molecular markers. Parents and their 60 individuals of an F1 progeny resulting from a cross 88-110 between 83-4-96 (Vitis quinquangularis, downy mildew-resistant) and Muscat Rose (V. vinifera, downy mildew-susceptible), three F2 progenies resulting from three crosses of self-cross and inter-cross of 88-110 F1 seedlings, as well as another interspecific F1 hybrids of 88-84 cross [Xun-3 (V. quinquangularis, downy mildew-resistant)×Ugni Blanc (V. vinifera, downy mildew-susceptible)] and the wild grapes native to China were used for the study. Among 280 Operon primers, 160 gave distinct band patterns. One RAPD marker OPO06-1500 was tightly linked to a major gene resistant to Plasmopara viticola (RPv-1). Based on Mapmaker software analysis, the map distance between RPv-1 and OPO06-1500 was 1.7cM. Marker OPO06-1500 was cloned and sequenced. According to the sequence, two specific primers were designed to amplify all plant materials. RAPD marker was converted into SCAR marker (SCO06-1500). One distinct single band only in resistant plants was amplified, whose size was the same as that of the RAPD marker. The SCAR marker’s popularity was confirmed, and it could be used for the identification of hybrid resistant to P. viticola and will be potentially useful in the development of new resistant grape cultivars.%以种间杂交组合88-110[83-4-96(毛葡萄,抗霜霉病)×粉红玫瑰(欧洲葡萄,感霜霉病)]的F1代(60个单株)及其自交或互交所得的3个F2代为试材,应用BSA、RAPD和SCAR方法研究了葡萄抗霜霉病基因的分子标记。共筛选了280个Operon引物,其中160个引物扩增出了清晰的DNA条带,发现了RAPD标记OPO06-1500与葡萄抗霜霉病主效基因(RPv-1)紧密连锁,经Mapmarker软件连锁分析,OPO06

  7. Effects of Saline-alkaloid Stress on the Seed Germination and Seedling Growth of Three Smooth Brome Varieties%混合盐碱胁迫对3种无芒雀麦种子萌发及幼苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    韩萌; 张月学; 潘多锋; 申忠宝; 王建丽; 张瑞博; 高超

    2012-01-01

    In order to discuss the saline-alkaloid-resistant ability of smooth brome,different concentration of saline-alkaloid liquor(0,20,40,60,80,100,120 mmol·L-1)mixed with NaCl,Na2SO4,NaHCO3 and Na2CO3 were used in smooth brome seed germination process.The effects of different concentration saline-alkaloid stress on the seed germination and seedling growth of three smooth brome varieties were studied.The results showed that low concentration of saline-alkaloid stress improved seed germination ability of mancher,and the other two varieties performing for the inhibition.When the saline-alkaloid concentration was under 60 mmol·L-1,the germination rate,germination index,vigor index and seedling growth were not significant(P〉0.05);While the saline-alkaloid concentration was exceed 60 mmol·L-1,all indexes fell sharply,and very significant difference compared to that of the control(P〈0.01).When the saline-alkaloid concentration was more than 20 mmol·L-1,the growth of seedling of three smooth brome varieties were inhibited,inhibition of root was higher than seedling inhibitory.%为了探讨无芒雀麦种子和幼苗的耐盐碱能力,在无芒雀麦种子萌发过程中,用浓度为0、20、40、60、80、100、120mmol.L-1的NaCl、Na2SO4、NaHCO3和Na2CO3混合液进行胁迫,研究了胁迫对3个无芒雀麦品种的种子萌发及幼苗生长的影响。结果表明:低浓度的混合胁迫处理促进无芒雀麦mancher的萌发和幼苗生长,其它2个品种均表现为抑制作用。当混合盐碱胁迫浓度小于60mmol.L-1时3个无芒雀麦品种的发芽率、发芽指数、活力指数和幼苗生长差异不明显(P〉0.05);当浓度高于60mmol.L-1后各个指标都急剧下降,且与对照差异极显著(P〈0.01)。混合盐碱浓度大于20mmol.L-1时抑制无芒雀麦幼苗的生长,对根的抑制作用强于对苗的抑制作用。

  8. The features of silver birch Betula verrucosa Ehrh. and downy birch Betula pubescens Ehrh. seed regeneration in subtaiga and forest-steppe of Western Siberia

    Directory of Open Access Journals (Sweden)

    B. E. Chizhov

    2016-12-01

    Full Text Available Article considers results of long-term studies of birch undergrowth in subtaiga subzone and forest-steppe zone of Western Siberia, the features of silver and downy birch seed regeneration under the canopy of parent stands, on logging, burned and abandoned arable lands, and hayfields. The distance of seed dispersal by wind, dynamics of accumulation of self-sown birch after continuous tillage and plough furrows is specified. It was found that seed regeneration under the birch stand canopy is hindered by drying of litter and root competition of the parent stand. A necessary condition for the germination of small seeds and the survival of weak shoots of birches is sufficient rainfall during the period of seed production and careful soil treatment, which provides removal of litter, total removal of herbaceous vegetation and soil reserve of weed seeds: continuous repeated plowing, bulldozing strips or shallow plow furrow with 0.7−1.0 m in width, with their additional cultivation. The most effective way of preparing land for seed regeneration of birch trees in arid steppe conditions is to transfer it under temporary cultivation of grain-crops, providing suppression of permanent weeds. Autumn plowing after harvest will provide annual readiness of the site for seed colonization of the birches. When there is an optimum combination of good seed harvest, rainy weather conditions, and appearance of mass self-sown birch, the land is excluded from the agricultural use. Prerequisites: the presence of seed productive walls of birch with preliminary removal of aspen and undesirable forms of birch. In spring of the next year an inventory is done of wintered self-sown birches, at least on 100 evenly spaced accounting plots. If the self-seeding dies, the site continues to be used by agriculture. Less reliable but acceptable is tillage by bulldozer stripes and furrows with 0.7−1.0 m in width, in a year of abundant seed production, before the start of mass seed

  9. Development and dissection of diagnostic SNP markers for the downy mildew resistance genes Pl Arg and Pl 8 and maker-assisted gene pyramiding in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Talukder, Z I; Hulke, B S; Foley, M E

    2017-02-03

    Diagnostic DNA markers are an invaluable resource in breeding programs for successful introgression and pyramiding of disease resistance genes. Resistance to downy mildew (DM) disease in sunflower is mediated by Pl genes which are known to be effective against the causal fungus, Plasmopara halstedii. Two DM resistance genes, Pl Arg and Pl 8 , are highly effective against P. halstedii races in the USA, and have been previously mapped to the sunflower linkage groups (LGs) 1 and 13, respectively, using simple sequence repeat (SSR) markers. In this study, we developed high-density single nucleotide polymorphism (SNP) maps encompassing the Pl arg and Pl 8 genes and identified diagnostic SNP markers closely linked to these genes. The specificity of the diagnostic markers was validated in a highly diverse panel of 548 sunflower lines. Dissection of a large marker cluster co-segregated with Pl Arg revealed that the closest SNP markers NSA_007595 and NSA_001835 delimited Pl Arg to an interval of 2.83 Mb on the LG1 physical map. The SNP markers SFW01497 and SFW06597 delimited Pl 8 to an interval of 2.85 Mb on the LG13 physical map. We also developed sunflower lines with homozygous, three gene pyramids carrying Pl Arg , Pl 8 , and the sunflower rust resistance gene R 12 using the linked SNP markers from a segregating F2 population of RHA 340 (carrying Pl 8 )/RHA 464 (carrying Pl Arg and R 12 ). The high-throughput diagnostic SNP markers developed in this study will facilitate marker-assisted selection breeding, and the pyramided sunflower lines will provide durable resistance to downy mildew and rust diseases.

  10. Adubação nitrogenada e potássica de bromeliáceas cultivadas em fibra de coco e esterco bovino Nitrogen and potassium fertilization of Bromeliaceae grown in coconut fiber and cattle manure

    Directory of Open Access Journals (Sweden)

    Tatiana L do Amaral

    2009-09-01

    Full Text Available Neste trabalho objetivou-se avaliar o efeito de doses de nitrogênio e de potássio no crescimento e teor foliar de nutrientes de quatro bromeliáceas comerciais e propor uma formulação de adubação adequada para cada planta estudada. O experimento foi em esquema fatorial (4 x 4, sendo quatro doses de nitrogênio (0; 375; 562,6 e 750 mg de N L-1 e quatro doses de potássio (0; 468,8; 703,2 e 937,6 mg de K L-1, em delineamento em blocos ao acaso, com quatro repetições para Aechmea blanchetiana e Neoregelia 'Sheba' e três repetições para Orthophytum gurkenii e Vriesea gigantea, duas plantas por parcela. As mudas de Aechmea blanchetiana e Neoregelia 'Sheba' foram cultivadas em substrato composto por 50% de fibra de coco + 50% de esterco bovino; as de Orthophytum gurkenii e Vriesea gigantea, em 100% de fibra de coco. As doses de nitrogênio 0; 375; 562,6 e 750 mg de N L-1 e potássio 0; 468,8; 703,2 e 937,6 mg de K L-1 no substrato correspondem, respectivamente, a 0; 187,5; 281,3 e 375 mg N/planta e 0; 234,4; 351,6 e 468,8 mg K/planta. A adubação fosfatada foi fixa, 50 mg de P L-1 no substrato, correspondendo a 25 mg P/planta, exceto para Neoregelia 'Sheba', que foi inoculada com 25 mL/vaso do inóculo micorrízico misto (Glomus geosporum, Acaulospora laevis, Acaulospora mellea e não recebeu adubação fosfatada. A adubação com 305,1 mg N/planta foi a que proporcionou maior incremento na altura de Aechmea blanchetiana. Em Orthophytum gurkenii; a adubação com 250 mg N/planta proporcionou o maior número de folhas e o maior diâmetro da roseta. As adubações nitrogenada e potássica não beneficiaram o crescimento das plantas de Vriesea gigantea. Em Neoregelia 'Sheba', a dose de 315 mg N/planta causou maior incremento em altura e diâmetro da roseta.Levels of nitrogen and potassium fertilization were evaluated on leaf nutrient contents of four commercial bromeliads, to recommend a suitable fertilization formula for each kind of plant

  11. Efeito de indutores no controle de míldio em Vitis labrusca Effect of elicitors in the control of downy mildew in Vitis labrusca

    Directory of Open Access Journals (Sweden)

    Regina Ceres Torres da Rosa

    2007-03-01

    to resource with the fungicide use aiming at its control. Aiming at to substitute the agrotóxico use it was evaluated in the cities of Are Vicente Férrer - PE (area 1, Natuba - PB (area 2 and Macaparana - PE (area 3 the effect of the induction of resistance promoted for DL- beta - aminobutyric acid (BABA, Agro-Mos (AM + Crop-set (Cs, Codavit (Cd and Ecolife (Ec was evaluated on grape variety 'Isabel'. Results have showed that AM + Cs was superior to the others treatments in reducing disease severity. In relation to efficiency control the AM + Cs treatment reduced disease severity in 37,46%, 35,97% and 18, 57% in the area 1, 2 and 3, respectively. The disease severity in the areas 1, 2, and 3, fitted the Y= e-3,36 . e-0,019t- (R= 0,66**, Y= 1/1 + 14,63 .e-0,037t (R= 0,84** and Y= e-4,13 . e- -0,034t (R= 0,62**, respectively. The severity of downy mildew in function of the time in the area 1, fit the gompertz model, except in the BABA treatment that was described by the equation logstic. In the area 2, a predominant model did not fit data from all treatments. The monomolecular model was described more frequently than others, in the treatments of area 3.

  12. Reaction of melon genotypes to the gummy stem blight and the downy mildew Reação de genótipos de melão ao crestamento gomoso e ao míldio

    Directory of Open Access Journals (Sweden)

    Gil R dos Santos

    2009-06-01

    Full Text Available The gummy stem blight (Didymella bryoniae and the downy mildew (Pseudoperonospora cubensis are two foremost melon (Cucumis melo diseases, considering their effects on yield and fruit quality. Despite the importance of such diseases, relatively few studies have been done so far on the identification of resistance sources to D. bryoniae and P. cubensis in Brazil. This work aimed at evaluating the resistance of commercial melon genotypes to the gummy stem blight and the downy mildew. Firstly, the most aggressive and representative D. bryoniae isolate was selected. Subsequently, the resistance of 86 melon genotypes to stem infection was studied upon greenhouse conditions by inoculating with the previously selected isolate. Afterwards, the resistance to mildew and leaf infection by D. bryoniae of 28 melon genotypes was evaluated in the field, under natural infection. In the greenhouse, all 86 melon genotypes were infected and showed stem infection symptoms caused by D. bryoniae four days after inoculation. Nevertheless, a significant variation on the resistance levels of the melon genotypes was found. Under field conditions and natural inoculation, genotypes Taslaki and Sary Juliabi were the most susceptible to leaf infection by D. bryoniae, significantly differing from the other genotypes. The lowest levels of susceptibility were identified in genotypes Perlita Busle S1, Valenciano Elíptico, Glaver, MR1, and 2526. All genotypes were susceptible to the downy mildew, albeit differing in susceptibility levels.O crestamento gomoso do caule (Didymella bryoniae e o míldio (Pseudoperonospora cubensis estão entre as principais doenças do meloeiro (Cucumis melo ocasionando redução da produtividade e da qualidade dos frutos. Apesar da importância dessas doenças, são poucos os trabalhos envolvendo a identificação de fontes de resistência a D. bryoniae e a P. cubensis no Brasil. O objetivo deste trabalho foi avaliar a resistência de gen

  13. Using SSH Technology to Identify Relevant Genes Resistant to Cucumber Downy Mildew%利用SSH技术鉴定黄瓜抗霜霉病相关基因

    Institute of Scientific and Technical Information of China (English)

    刘大军; 秦智伟; 周秀艳; 辛明; 武涛

    2014-01-01

    Adopting SSH technology,this paper studied on the difference expressive genes of downy mildew resistant cucumber inbred line ‘M801-3-1’ before and after the infection of downy mildew.Disease-resistant cucumber material vaccinated downy mildew and unvaccinated cDNA library was constructed using SSH technology.Forty-eight positive clones were obtained by reverse Northern blot hybridization detection, and 14 UniESTs were obtained including 8 singletons and 6 contigs via molecular biology software.The SSH-EST genes function analysis indicated that oxidative stress resistance and chloroplast reconstruction and protection mechanisms had very important role on disease resistance.At the same time,the paper put forward that Clpb,HSP70,HSP22 and peptidyl-prolyl cis-trans isomerase might be involved in the R gene-mediated defense reaction,and smHSP might be the ‘defending target’ of R protein,responsible for monitoring intracellular exception.This study has provided a key evidence for revealing the relations between active oxygen mechanism and R gene mediate protection mechanism.%采用SSH技术对黄瓜抗霜霉病自交系M801-3-1侵染霜霉病菌前后的差异表达基因进行了研究。利用 SSH 技术构建抗病黄瓜材料接种霜霉病菌和未接种差异表达的差减cDNA文库。经反向Northern blot杂交检测,共得到48个阳性克隆。利用分子生物学软件对测序后的序列进行质量检测和聚类、拼接,共得到14个UniESTs,其中包括8个singletons和6个contigs。通过SSH-EST代表基因功能的分析,说明抗氧化胁迫能力和叶绿体的重建和保护机制对抗病品种抗病有重要作用。同时,提出SSH-EST代表的clpb、HSP70、HSP22和肽脯氨酰顺反异构酶还可能参与了R基因介导的防御反应,smHSP有可能就是R蛋白的“保卫靶”,负责监测细胞内的异常,这一发现为揭示活性氧机制和R基因介导的防卫机制之间的关系提供了关键证据。

  14. 基于半监督模糊聚类的黄瓜霜霉病受害程度识别研究%Research on Disease Level of Cucumber Downy Mildew Based on Partial Fuzzy C-means Algorithm

    Institute of Scientific and Technical Information of China (English)

    施伟民; 杨昔阳; 李志伟

    2012-01-01

    通过定义一种新的半监督模糊聚类算法,提高聚类算法的运行效率和可解释性,结合Fisher线性判别分析,对黄瓜霜霉病的受害程度进行识别研究.针对7个关于叶片色调信息的统计特征,利用判别分析提取出2个主分量.结合一部分叶片的类别属性,对所有叶片的这2个主分量,进行半监督聚类分析.结果表明,对于类别属性已知的叶片,聚类结果与已知类别的一致率达100%,而对于类别未知的数据,一致率也达到95%以上.%A novel fuzzy C-means algorithm is proposed to improve the intelligibility and computing efficiency of semi-supervised cluster algorithm. Based on Fisher linear discriminant and the proposed algorithm, the disease level of cucumber leaves infected by cucumber downy mildew are studied. 7 hue statistics of cucumber leaves are measured,and 2 feature parameters are founded based on linear discriminant analysis. The result of the partial Fuzzy Gmeuns alyorithm shows that the correct recognition rata is 100% on sample data,and above 95% on test data.

  15. Using High-Resolution Future Climate Scenarios to Forecast Bromus tectorum Invasion in Rocky Mountain National Park

    OpenAIRE

    Amanda M West; Sunil Kumar; Tewodros Wakie; Brown, Cynthia S; Stohlgren, Thomas J.; Melinda Laituri; Jim Bromberg

    2015-01-01

    National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the pot...

  16. Survival of a Rifampicin-Resistant Pseudomonas fluorescens Strain in Nine Mollisols

    Directory of Open Access Journals (Sweden)

    Tami L. Stubbs

    2014-01-01

    Full Text Available Pseudomonas fluorescens strain D7 (P.f. D7 is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorum L., in crop- and rangelands. Pseudomonas fluorescens strain D7rif (P.f. D7rif is a rifampicin-resistant strain of P.f. D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated with P.f. D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival of P.f. D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highest P.f. D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery of P.f. D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days, P.f. D7rif was recovered at levels greater than log 5.5 colony forming units (CFU g−1 soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.

  17. Diversidade de bromeliáceas epífitas na Área de Proteção Ambiental Ilha do Combu, Belém, Pará, Brasil Diversity of epiphytic bromeliads in the environmental protection area of Combu Island, Belém, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Adriano Costa Quaresma

    2012-06-01

    Full Text Available Informações sobre a diversidade no nível de espécie oferecem subsídios importantes para o desenvolvimento sustentável e a conservação biológica. Neste contexto, estudos com Bromeliaceae merecem destaque, especialmente porque o grupo é importante ecologicamente, mas ainda pouco conhecido na Região Norte. Neste trabalho, foram demarcadas duas parcelas de 100 m x 100 m em uma floresta de várzea localizada na Área de Proteção Ambiental Ilha do Combu, em Belém, Estado do Pará. Cada parcela foi subdividida em oito parcelas de 50 m x 50 m, tendo todas as espécies e espécimes de bromeliáceas epífitas registradas e quantificadas. A diversidade do grupo foi calculada utilizando o índice de Shannon-Wiener. Foram registrados 1.339 indivíduos pertencentes a oito espécies e quatro gêneros. Tillandsia e Aechmea apresentaram maior riqueza. A diversidade de espécies na área foi de H= 1,10, apresentando dominância acentuada de muitos indivíduos em poucas espécies.Information about diversity at the species level offers data for sustainable development and biological conservation. In this context, studies about Bromeliaceae are noteworthy, especially because this group is ecologically important and poorly known in the North Region of Brazil. In this study, two grids (100 m x 100 m were delineated in a floodplain forest in the environmental protection area of Combu Island, Belém, Pará, Brazil. The grids were subdivided into eight grids of 50 m x 50 m, and all species and individuals of epiphytic Bromeliaceae were recorded and quantified. The diversity was calculated using the Shannon-Wiener index. A total of 1,339 individuals, belonging to eight species and four genera were recorded. Tillandsia and Aechmea presented the greatest richness. The diversity of species was H= 1.10, presenting sharp dominance of many individuals of few species.

  18. 萝卜霜霉病、黑斑病、白斑病、白锈病、炭疽病和黑根病的识别与防治技术%ldentification and Control Method of Radish Downy Mildew, Melasma, Leuko-derma, White Rust, An-thracnose and Black Root

    Institute of Scientific and Technical Information of China (English)

    金苹

    2012-01-01

    This paper introduced the damage characteristics and occurrence regularity of radish downy mildew, melasma, leukoderma, white rust, an-thracnose and black root. Then it pro-posed the corresponding control methods from two aspects including agricultural control and chemical control.%介绍了萝卜霜霉病、黑斑病、白斑病、白锈病、炭疽病及黑根病的危害症状、发病特点,指出各种病害的识别特点,并从农业措施、化学防治等方面提出了相应的防治方法。

  19. William L Finley - Slender False-brome Eradication

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — William L. Finley NWR contains some of the largest and best examples of remaining Oregon white oak woodland, oak savanna, and prairie habitats remaining in the...

  20. Bromeliáceas notables de Colombia,-ll

    Directory of Open Access Journals (Sweden)

    Smith Lyman B.

    1942-11-01

    Full Text Available Aechmea setigera / Aechmea tillandsioides / Billbergia rupestris / Guzmania cryptantha / Guzmania minor / Guzmania Mosquerae / Navia acaulis / Pitcairnia heliophila / Streptocalyx colombianus

  1. Bromeliáceas Notables de Colombia, III

    Directory of Open Access Journals (Sweden)

    Smith Lyman B.

    1945-04-01

    Full Text Available Aechmea (Platyaechmea anómala / Greigia excerta / Guzmania coriostachya / Guzmania cryptantha / Guzmania gloriosa / Pitcairnia alborubra / Pitcairnia bella / Pitcairnia oblanceolata / Pitcairnia Schultzei / Pitcairnia semaphora / Tillandsia chontalensis / Tillandsia disticha / Tillandsia excavata / Tillandsia Funckiana / Tillandsia Gardneri / Tillandsia (Platystachys mima / Tillandsia rectiflora

  2. Bromeliáceas notables de Colombia. - 1

    Directory of Open Access Journals (Sweden)

    Smith Lyman B.

    1942-06-01

    Full Text Available Aechmea contracta / Aechmea nívea / Aechmea Schultesiana / Brocchinia serrata / Guzmania brasiliensis / Guzmania vittata / Pitcairnia caricifolia Mart. / Pitcairnia Cuatrecasana L. / Pitcairnia tolimensis / Pitcairnia turbinella / Vriesia chrysostachys E.

  3. Influência das condições climáticas sobre a eficácia de fungicidas empregados para o controle do míldio em Vitis vinifera Effect of environmental conditions on efficacy of fungicides to downy mildew control in Vitis vinifera

    Directory of Open Access Journals (Sweden)

    Ana Beatriz Costa Czermainski

    2004-02-01

    Full Text Available Um dos fatores a serem manejados para a máxima produtividade de um vinhedo é o míldio, doença causada por Plasmopara viticola, que afeta regiões produtoras de uva do mundo inteiro. No Brasil, são necessárias diversas aplicações de fungicida para seu controle. Diferentes princípios ativos são encontrados no mercado. Com base em resultados de ensaios de fungicidas para controle do míldio em Vitis vinifera conduzidos em 1995 e 1996, foi analisada a influência dos fatores climáticos temperatura do ar, precipitação e umidade relativa do ar sobre a eficácia dos produtos disponíveis. Os experimentos foram instalados na Embrapa Uva e Vinho, sobre a cv. Tannat, conduzida no sistema espaldeira. A análise dos fatores ambientais apontou períodos de infecções primárias e secundárias. A maior ocorrência de chuvas e alta umidade relativa do ar foram determinantes da maior severidade do míldio no ano de 1996. A análise da incidência e do índice de intensidade de doença em folhas e em cachos, indicou maior eficácia dos fungicidas cymoxanil + mancozeb, metalaxil + mancozeb e dithianona, nos dois anos. Os princípios ativos cúpricos - oxicloreto de cobre, isolado ou combinado com mancozeb, e sulfato de cobre - não foram eficazes para controlar o míldio nos cachos sob condições climáticas favoráveis à doença.One of the factors to be managed for maximum vineyard productivity is the downy mildew, disease caused by Plasmopara viticola that affects grape production in many parts of the world. In Brazil, several fungicide applications for its control are necessary. Different active ingredients are available on the market. The influence of climatic factors (air temperature, rainfall and relative humidity on fungicide efficacy in Vitis vinifera was analyzed using results of fungicide trials for downy mildew control as a base. The experiments were carried out at Embrapa Uva e Vinho with the cv. Tannat conducted on vertical trellis

  4. 壳聚糖与水杨酸复配对小白菜霜霉病与盐胁迫复合逆境的诱抗作用%Role of chitosan and salicylic acid application in induction of Brassica chinensis resistance to dual stress of downy mildew and salt stress

    Institute of Scientific and Technical Information of China (English)

    徐芬芬; 李坚; 罗晓燕

    2011-01-01

    为探明壳聚糖(CTS)和水杨酸(SA)复配处理对小白菜(Brassica chinensis L.)复合逆境的诱抗作用和效果,采用根际施用结合叶面喷洒的方法,研究了CTS与SA复配对小白菜盐和霜霉病胁迫复合逆境的诱抗作用.结果表明:SA、CTS单一与复配施用均能显著降低复合逆境下小白菜的盐害指数和病情指数,提高复合逆境下小白菜的株高、展开叶数、最大叶片面积和单株干质量等形态指标,促进小白菜在复合逆境下的正常生长,降低小白菜叶片的丙二醛(MDA)含量,增强过氧化物酶(POD)、多酚氧化酶(PPO)等保护酶的活性.在复合逆境下,SA、CTS复配施用对小白菜的诱导抗病和抗盐效果显著,盐害指数和病情指数均低于SA、CTS单一处理,且抗病和抗盐的共效系数均分别为-14.76和1.72,均表现为相加作用.%The role of chitosan (CTS) and salicylic acid (SA) compound application in induction of pakchoi (Bras-sica chinensis L. ) resistance to dual stress of downy mildew and salt stress was studied by the method of rhizosphere application with foliar spray. The results showed that both separate and joint application of SA and CTS significantly reduced salt injury index and disease index of pakchoi under the dual stress, increased the plant height, the number of expanding leaves, maximum leaf area, plant dry weight and other morphological indicators, and promoted the normal growth of pakchoi under dual stress, reduced malondialdehyde (MDA) content of leaves, and enhanced peroxidase (POD) and polyphenol oxidase (PPO) activities. The effects of CTS and SA joint application on the induction of resistance against downy mildew or salt stress in pakchoi were significant under the dual stress, with the salt injury index and disease index lower than those of single CTS or SA application. In the treatment of CTS and SA joint application, the coefficients of disease resistance and salt tolerance were -14.76 and 1

  5. Novas raças de Bremia lactucae, agente causador do míldio da alface, identificadas no estado de São Paulo New races of Bremia lactucae, causal agent of lettuce downy mildew, identified in São Paulo state, Brazil

    Directory of Open Access Journals (Sweden)

    Jean de O Souza

    2011-09-01

    Full Text Available O objetivo deste trabalho foi relatar o surgimento de raças de Bremia lactucae, agente causal do míldio nas principais regiões produtoras de alface do estado de São Paulo. O estudo foi realizado no Laboratório de Melhoramento Genético de Hortaliças do Departamento de Produção Vegetal da UNESP, Campus de Jaboticabal. No período de 2006 e 2007, foram coletados 36 isolados de B. lactucae de diferentes regiões produtoras de alface no estado. Para identificação das raças foram utilizadas as cultivares diferenciadoras conforme o código "Sextet". Foram identificadas três novas raças, SPBl:02, SPBl:03 e SPBl:04 com os referidos comportamentos do fungo: (63/31/19/00, (63/63/19/00 e (63/63/03/00. Os genes Dm-14, Dm-17, Dm-18, Dm-37 e Dm-38 conferem resistência a essas novas raças identificadas.The objective of this paper was to report new races of lettuce downy mildew causal agent Bremia lactucae in São Paulo State. The study was carried out in the laboratory of Crop Genetics in the Department of Crop Science at the college of Agricultural and Veterinary Sciences, Jaboticabal campus. A total of 36 isolates of B. lactucae was collected in different regions. The identification of races was based on compatibility reaction on the differential cultivars of the "Sextet". Three new races of B. lactucae, SPBl:02 (63/31/19/00, SPBl:03 (63/63/19/00 and SPBl:04 (63/63/03/00 were identified according to "Sextet" code. Genes Dm-14, Dm-17, Dm-18, Dm-37 and Dm-38 confer resistance to these new races identified.

  6. Aplicação foliar de tratamentos para o controle do míldio e da podridão-de-escamas de bulbos de cebola Foliar spray of treatments in the control of downy mildew and bulb rot in onion

    Directory of Open Access Journals (Sweden)

    João Américo Wordell Filho

    2007-12-01

    Full Text Available Em experimento de campo, avaliou-se o efeito da aplicação foliar de tratamentos para o controle do míldio (Peronospora destructor e da podridão de bulbos (Burkholderia cepacia de cebola: testemunha, clorotalonil/metalaxyl + clorotalonil, fosfito de potássio, fertilizante foliar (03-00-16, N-P-K, calda bordalesa, calda bordalesa/fosfito de potássio, acibenzolar-S-methyl, pulverizados semanalmente; extrato de alga (Ulva fasciata e ulvana, aplicados a cada 7, 14 e 21 dias. Somente a pulverização semanal com fungicidas sintéticos ou com o fertilizante (03-00-16; 400 mL de p.c./100 L foi capaz de reduzir significativamente a severidade do míldio, em 60 ou 23%, respectivamente, em relação à testemunha não pulverizada, sem aumentar o rendimento de bulbos. O tratamento com fertilizantes ricos em potássio resultou em maior incidência da podridão de bulbos armazenados por cinco meses. O conteúdo de açúcares solúveis e incidência da podridão de bulbos de cebola foram correlacionados significativamente (-0,629, p A field experiment was carried out to evaluate the effect of foliar sprays with the following treatments on the downy mildew (Peronospora destructor and bulb rot (Burkholderia cepacia in onions: non-treated control, fungicide chlorotalonil/metalaxyl + chlorotalonil, potassium phosphite, foliar fertilizer (03-00-16, N-P-K, bordeaux mixture, bordeaux mixture/potassium phosphite, acibenzolar-S-methyl weekly applied; extract of alga Ulva fasciata and ulvan sprayed every 7, 14 and 21 days. Only the weekly spraying of fungicides and fertilizer (03-00-16, 400 mL/100 L significantly reduced the mildew severity by 60 and 23%, respectively, but did not increase the bulb yield. The foliar application of potassium rich fertilizers resulted in a higher incidence of rotten bulbs after 5 months in storage. Soluble sugar content and rot incidence of onion bulbs were significantly correlated (-0,629, p < 0,05.

  7. Application and validation of a warning system for grapevine downy mildew controlusing fungicides Aplicação e validação de um sistema de aviso para o controle do míldio da videira, com fungicidas

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    Erlei Melo Reis

    2013-03-01

    Full Text Available Most warning systems for plant disease control are based on Vinho, in Bento Gonçalves - RS, during the growing seasons 2000/ weather models dependent on the relationships between leaf wetness 01, 2002/03 and 2003/2004, using the grape cultivar Isabel. The duration and mean air temperature in this period considering the conventional system used by local growers was compared with the target disease intensity. For the development of a warning system to new warning system by using different cumulative daily disease severity control grapevine downy mildew, the equation generated by Lalancette values (CDDSV as the criterion to schedule fungicide application and et al. (7 was used. This equation was employed to elaborate a critical reapplication. In experiments conducted in 2003/04, CDDSV of 12 - period table and program a computerized device, which records, though 14 showed promising to schedule the first spraying and the interval electronic sensors, leaf wetness duration, mean temperature in this between fungicide applications, reducing by 37.5% the number of period and automatically calculates the daily value of probability of applications and maintaining the same control efficiency in leaves infection occurrence. The system was validated at Embrapa Uva e and bunches, similarly to the conventional system.A maioria dos sistemas de aviso para o controle de doenças de O sistema foi validado na Embrapa Uva e Vinho, em Bento Gonçalves plantas utilizam como fundamento o modelo climático baseado - RS, conduzido nas safras agrícolas de 2000/01, 2002/03 e 2003/ nas interações entre a duração do molhamento foliar e a 2004 utilizando-se o cultivar Isabel. O sistema convencional utilizado temperatura média nesse período sobre a intensidade da doença pelos produtores foi comparado com o modelo de aviso utilizando alvo. No desenvolvimento de um modelo de aviso para o controle como critério indicador do momento para a aplicação e reaplicação do m

  8. The effects of biological control of Bacillus subtilis strains on downy mildew and anthracnose diseases of harvested litchi fruits%枯草芽胞杆菌对离体荔枝果实霜疫霉病、炭疽病的防治效果

    Institute of Scientific and Technical Information of China (English)

    黄庶识; 黄曦; 张荣灿; 许兰兰; 雷富; 黄荣韶

    2011-01-01

    Four antagonistic bacteria strains, OR-1, OR-2, OR-3 and ON-6, which were isolated and screened from soil under litchi trees and identified as Bacillus subtilis morphologically and molecularly, were used to evaluate the control effect on downy mildew and anthracnose diseases of harvested litchi fruits. The results showed that all 4 strains had obvious inhibiting action on mycelial growth of Peronophy-thora litchii and Colletrichum gloeosporiodes, among them, ON-6 strain had the highest inhibitory rate to mycelial growth of two litchi pathogenic fungi, the ratio were 92.34% and 70. 36% respectively; the next best was ON-1, its ratio were 82. 93% and 54. 61% severally. The browning index of the four strains treatment groups was lower than that of the control group and fungicide groups significantly ( P <0.05 ) , in which OR-1 strain had the best impact. Metabolites of four B. subtilis strains had a better effect in pre-venting P. litchii and C. gloeosporiodes on the surface of fresh fruits than those of CK group and fungicide groups at room temperature for 3 -4 d or at 4 X. for 40 d significantly (P < 0. 05 ) , which ON-6 strain showed best at room temperature, likewise, ON-6 and ON-3 strains showed best at 4 °C , indicated that the four B. subtilis strains could inhibit litchi pathogenic fungi on the surface of fruits determinately, and extend the period of storage and delay the fresh fruits to brown stain at room temperature or at 4 t.%为了进一步明确从土壤中筛选得到的拮抗细菌OR-1、OR-2、OR-3、ON-6的分类地位和生防效果,采用形态学观察、理化特性结合分子生物学方法,鉴定这4株细菌皆为枯草芽胞杆菌Bacillussubitilis.拮抗菌对荔枝霜疫霉菌、炭疽菌菌丝生长均具有明显抑制作用,ON-6菌株的发酵液对菌丝生长的抑制率最高,分别为92.34%和70.36%,其次是OR-1菌株.拮抗菌处理组褐变指数均小于对照组以及杀菌剂处理组,且差异达显著水平(P<0.05),OR

  9. Detecção e variabilidade de Plasmopara halstedii no Brasil e avaliação da resistência de genótipos de girassol ao míldio Detection and variability of Plasmopara halstedii in Brazil and resistance of sunflower genotypes to downy mildew

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    Regina Maria Villas Bôas de Campos Leite

    2007-12-01

    Full Text Available Este trabalho foi conduzido com o objetivo de identificar a raça fisiológica de Plasmopara halstedii que ocorreu em plantas de girassol coletadas no campo experimental da Embrapa Soja, Londrina, PR, em 1998, 2001 e 2002 e avaliar a reação de genótipos de girassol ao míldio. Plântulas de girassol das diferenciadoras de raças e das cultivares foram inoculadas com suspensão de zoosporângios do patógeno e foram plantadas em caixas contendo areia autoclavada. As plântulas foram mantidas em câmara climatizada, com temperatura controlada em 21ºC, por 11 dias. Em seguida, as plantas foram aspergidas intensamente com água destilada, cobertas com saco plástico e mantidas no escuro, a 18ºC. No dia seguinte, foi observada a presença de esporulação nos cotilédones. As plantas que apresentaram esporulação foram consideradas suscetíveis e as sem esporulação foram resistentes. O resultado indicou tratar-se da raça 330 (antiga raça 7 americana, nas três ocasiões. Os genótipos de girassol Embrapa 122, BRS 191 e as cultivares de girassol ornamental BRS Capri M, BRS Encanto M, BRS Oásis, BRS Paixão M, BRS Pesqueiro M, BRS Refúgio M, BRS Saudade M e BRS Saudade U e seus respectivos parentais foram suscetíveis a P. halstedii raça 330. Os genótipos AGROBEL 910, AGROBEL 920, AGROBEL 960, AGROBEL 965, C11, EXP38, M734, M742 e RUMBOSOL 91 foram resistentes à raça 330 do patógeno e podem ser indicados aos agricultores para uso em regiões de risco de ocorrência da doença.This research was carried out for identifying the physiological race of Plasmopara halstedii occurring in sunflower at the experimental field of Embrapa Soybean, Londrina, PR, Brazil, in 1998, 2001 and 2002 by evaluating the reaction of sunflower genotypes inoculated with downy mildew pathogen. Sunflower seedlings of the differentials set to identify races and of the cultivars were inoculated by immersion in zoosporangia suspension and were grown in autoclaved

  10. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... gravity meter with sensitivity of 0.01 g and by means of formula 1. The 1st and 2nd age ... multiplying these values the area of a leaf (l.a, mm2) is calculated. 4. ..... Considering obtained data from this study of effects of leaf area ...

  11. Susceptibility level of cucumber downy mildew (Pseudoperonospora cubensis to metalaxyl

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    Bagi Ferenc F.

    2009-01-01

    Full Text Available Level of susceptibility of Pseudoperonospora cubensis isolate from Ratkovo to metalaxyl in concentrations 50, 100, 200, 400 and 800 μg/ml was investigated. The trials were conducted on cotyledon and fully developed young leaves using cucumber cultivar Haroš. Reduced level of susceptibility was detected in metalaxyl concentrations of 50, 100 and 200 μg/ml because the intensity of sporulation in these treatments was on the same level as in control. Sporulation was also observed on developed leaves treated with metalaxyl in concentrations of 400 and 800 μg/ml.

  12. Atahualpa’s Revenge: The Spread of Quinoa Downy Mildew

    OpenAIRE

    Testen, Anna L.; Backman, Paul A.

    2011-01-01

    Metadata only record The Andean crop quinoa, Chenopodium quinoa, has gained popularity in recent years due to its nutritious seed and desirable agricultural traits, such as its tolerance to drought and high saline soils. Prized by the Inca, quinoa is now highly desirable to health conscious consumers in North America and Europe. Quinoa also has interesting applications to plant pathology, including being a “universal” virus host as well as its production of antimicrobial compounds. Quinoa ...

  13. Microflora de Bromeliáceas do estado de Pernambuco, Brasil

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    Luis Tavares de Lyra

    1976-01-01

    Full Text Available O autor estudou a microflora de dois gêneros de BROMELIACEAE: Hoenbergia e Portea. As coletas do material foram feitas em seis regiões do Estado de Pernambuco; 1 Região da Mata-Úmida; 2 Região da Mata-Seca; 3 Região do Agreste Central; 4 Região do Agreste Setentrional; 5 Região do Agreste Meridional; 6 Região do Recife. As seguintes diatomáceas indicadoras de águas poluídas (espécies oligossaprobias foram encontradas nas seis regiões estudadas: Gomphonema parvulum (Kutz Grunow., Hantzschia amphioxys Grunow, Pinnularia borealis Ehr., Pinnularia microstauron (Ehr Cleve, gomphonema gracile Ehr., Nitzschia palea Kutz., Melosira roeseana Rabenh., Navicula mutica Kutz., Navicula cryptocephala Kutz., Eunotia pectinalis (Kutz Rabenh. Foram também observadas CHLOROPHYCEAS nas estações chuvosa e seca nas diversas regiões. Algumas são indicadoras de oligossaprobidade: Scenedesmus quadricauda (Turpin brebisson. Chlorococcum sp., Chlorella sp. Os fatores ecológicos e comentários referentes ás diatomáceas foram anotados no texto. A tabela I indica a frequência das diatomáceas nas seis regiões estudadas. Maior número dessas diatomáceas, registramos nas regiões do Agreste. A tabela II mostra a temperatura e pH da água de Hoenbergia e Portea em ambas as estações do ano (inverno e verão. Observamos a ocorrência de larvas de culex em Portea e hoenbergia, entretanto, raramente encontramos larvas de Anopheles. As coletas foram feitas durante as estações chuvosa e seca em Hoenbergia e Portea. Determinamos 35 espécies provenientes de 78 amostras coletadas durante o período de 26 meses.The author studied the microflora from two genera of Bromeliaceae: Hoenbergia and Portea. The material was collected in six natural regions of Pernambuco State: 1 Humid Forest Region; 2 Dry forest region; 3 Central Agreste Region; 4 Setentrional Agreste Region; 5 Meridional Agreste Region; 6 Recife Region. The following diatoms that indicate polluted water (oligosaprobic species have been found in the six Regions studied: Gomphonema parvulum (Kutz Grunow, Hantzschia amphioxys Grunow, Pinnularia borealis Ehr., Pinnularia microstauron (Ehr Cleve, Gomphonema gracile Ehr., Nitzschia palea Kutz., Melosira roeseana Rabenh., Navicula mutica Kutz., Navicula cryptocephala Kutz., Eunotia pectinalis (Kutz Rabenh. Chlorophyceae were also found in samples collected in rainy and dry seasons. some are indicators of oligosaprobic conditions: Sceneaesmus quadricauda (Turpin Brebisson, Chloro coccum sp., Chlorella sp. Ecological factors and comments, concerning diatoms are reported in the text. Most part of diatoms we have reported in the Agreste Regions. Table (I shows the frequency of diatoms in the six Regions studied. Table (II indicates temperature and pH of the water of the bromeliads Hoenbergia and Portea in both seasons of the year (winter and summer. We report the occurence of Culex larvae in Portea and Hoenbergia, however, we also found Anopheles larvae, but they were rarely observed. Collections were made in the rainy and dry seasons in Hoenbergia and Portea. A total of 35 species was determined from 78 samples collected during a period of 26 months.

  14. Evaluation of the effectiveness of different herbicides against a new weed Japanese brome (Bromus japonicus Houtt. in wheat crop

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    Muhammad Asghar

    2017-06-01

    Full Text Available A field experiment was conducted to evaluate the efficacy of different post emergence herbicides for the control of monocot weed the Japanese broom (Bromus japonicus in wheat crop. Five herbicides viz., metribuzin, isoproturon, metribuzin plus isoproturon, Atlantis and sulfosulfuron were used at their recommended doses in RCBD with three replications. The weedy check was kept as control where no herbicide was sprayed. All the herbicides were applied as post-emergence after second irrigation at 60 days after sowing the crop. The lowest weed counts per m2 (0.583 and highest percent of weed mortality (99.07% were observed where metribuzin plus isoproturon was used. This was followed by Atlantis with 3.26 weeds per m2 with 95.14% mortality of weeds. However, significantly higher 1000 grain weight was noted with Atlantis (29.50 g and metribuzin plus isoproturon (28.58 g. The treatments did not differ significantly with respect to 1000 grain weight. All the herbicide helped to increase the yield from 16 to 22%, but did not differ significantly with respect to yield gain. The highest yield (3759.40 kg ha-1 was produced by Atlantis followed by sulfosulfuron (3757.20 kg ha-1 . On the basis of cost benefit ratio sulfosulfuron (34.95 proved to be the best followed by metribuzin (16.78. Therefore, sulfosulfuron and metribuzin are recommended for the control of Bromus weed in wheat crop.

  15. Self-fertility and other distinguishing characteristics of a new morphotype of Puccinia coronata pathogenic on smooth brome grass.

    Science.gov (United States)

    Anikster, Y; Eilam, T; Manisterski, J; Leonard, K J

    2003-01-01

    A new morphotype of Puccinia coronata, pathogenic to Bromus inermis, a common roadside and pasture grass in the northern United States, was discovered in the 1990s and described as P. coronata f. sp. bromi by Delgado et al in 2001. Puccinia coronata f. sp. bromi does not require fertilization of pycnia to produce aecia on its alternate host, whereas fertilization is required in all other varieties or formae speciales of P. coronata with aecial hosts in the family Rhamnaceae and for which life cycles have been described. Promycelia of P. coronata f. sp. bromi produce only two basidiospores, and each receives a pair of nuclei from the promycelium. The nuclei divide again so that mature basidiospores each contain four nuclei. Puccinia coronata f. sp. bromi has smaller teliospores than P. coronata var. avenae, and its substomatal vesicles are non-septate and distinctly shaped compared to those of P. coronata var. avenae. In addition, nuclei of P. coronata f. sp. bromi contain less DNA than those of P. coronata var. avenae. Puccinia coronata f. sp. bromi is further distinguished from P. coronata var. avenae and P. coronata var. hordei in being avirulent on both oat and barley, whereas neither P. coronata var. avenae nor P. coronata var. hordei are virulent on Bromus inermis.

  16. OUTBREAK OF MAIZE DOWNY MILDEW (Sclerophthora macrospora IN SLOVENIA IN 1999

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    Stanislav Trdan

    2000-12-01

    Full Text Available In 1999 a pronounced infection of maize with fungus Sclerophthora macrospora occurred in Slovenia, especially in its north-eastern and eastern regions. Symptoms, typical for infection with this fungus, were found on app. 1800 ha, which means on about 2.5 % of the acreage on which maize is grown. The infected plants were found only on those fields, or parts of those fields, which were flooded for some time soon after sowing or emergence of the crop. The percentage of the plants infected by the fungus was between 5 and 90 %, depending on the type of soil. This article presents different disease causing fungi, their taxonomy, and deals in detail with the species Sclerophthora macrospora, the only disease causing organism under our growing conditions. The article deals with hosts of the fungus, typical symptoms of the disease on maize (“crazy top”, pathogen biology, the mode of infection, its survival under unfavorable conditions, and possible protection against the infection. The article also describes the actual situation in Slovenia, and adds a comment on possible regular occurrences of this disease in future.

  17. Photosynthetic responses of lettuce to downy mildew infection and cytokinin treatment.

    Science.gov (United States)

    Prokopová, Jitka; Spundová, Martina; Sedlárová, Michaela; Husicková, Alexandra; Novotný, Radko; Dolezal, Karel; Naus, Jan; Lebeda, Ales

    2010-08-01

    Changes in primary metabolism of lettuce, Lactuca sativa L. (cv. Cobham Green), induced by compatible interaction with the biotrophic oomycete pathogen Bremia lactucae Regel (race BL 16), under two intensities of illumination in the presence and absence of exogenous cytokinins were studied by chlorophyll fluorescence imaging. Thirteen days post-inoculation leaf discs infected by B. lactucae exhibited impairments of photosynthesis associated with biotrophic infections, including: reductions in photosynthetic pigment contents and the maximum quantum yield of photosystem II photochemistry (F(V)/F(M)), inhibition of electron transport (Phi(PSII)) and increased non-photochemical chlorophyll fluorescence quenching (NPQ). Detected changes in photosynthetic parameters correlated with the leaf area colonized by the pathogen's intercellular hyphae. Applications of two cytokinins, benzylaminopurine and meta-topolin, previously shown to suppress B. lactucae sporulation if applied 24 h prior to inoculation at a concentration of 200 microM, retarded the pathogen's asexual reproduction with no apparent negative effects on the host's photosynthetic apparatus. However, long-lasting treatment of healthy tissues with this high concentration of exogenous cytokinin led to effects parallel to pathogenesis: reductions in photosynthetic pigment contents accompanied by inhibition of photosystem II photochemistry and electron transport. These effects of both prolonged exposure to cytokinins and the pathogenesis were weaker in discs exposed to the lower photosynthetic photon flux density. The role of cytokinins in plant-biotrophic pathogen interactions and their potential as disease control agents are discussed.

  18. Linkage analysis of genes for resistance to downy mildew (Bremia lactucae) in lettuce (Lactuca sativa).

    Science.gov (United States)

    Hulbert, S H; Michelmore, R W

    1985-08-01

    The genetics of specific resistance was studied in F2 populations which segregated for either one or two resistance genes. The resistance factors 1, 11 and 14 which had not previously been characterized genetically segregated as single dominant genes (Dm). Resistance was determined by three linkage groups; R 1/14, 2, 3, and 6 in the first, R 5/8, and 10 in the second and R 4, 7 and 11 in the third. Cultivars of lettuce commonly used in the differential series to detect virulence to R3 and R10, were demonstrated to carry two tightly linked resistance genes. Implications of this linkage arrangement to the manipulation and characterization of these resistance genes are discussed.

  19. Plasmopara halstedii virus causes hypovirulence in Plasmopara halstedii, the downy mildew pathogen of the sunflower.

    Science.gov (United States)

    Grasse, Wolfgang; Zipper, Reinhard; Totska, Maria; Spring, Otmar

    2013-08-01

    Plasmopara halstedii virus (PhV) is an isometric virus recently found in the oomycete Plasmopara halstedii. The fully sequenced virus genome consists of two ss(+)RNA strands encoding for the virus polymerase and the coat protein, respectively. Most of previously screened field isolates of P. halstedii were found to harbor PhV, but effects of PhV on the pathogenicity and aggressiveness of the oomycete have not been investigated yet. To assess the influence of PhV on the infectivity of P. halstedii, virus-free isolates of the oomycete were searched for, cultivated on sunflower and used for single zoospore infection. Four genetically homogenous strains belonging to three different pathotypes (710, 730, 750) were established. Subcultures of each strain were successfully infected with PhV. This afforded pairs of isogenic strains with and without virus and allowed assessment of the pathogenicity (susceptibility to specific sunflower genotypes) and aggressiveness (intensity of infection, time scale and density of sporulation) in cultivation of sunflower. While no significant difference was found in the pathogenicity of P. halstedii strains with and without virus towards sunflower seedlings of different resistance (pathotype differentials), the aggressiveness of the oomycete was diminished by PhV. Compared to the virus-free strains, the time required for the first sporulation (latent period) increased by about 1 day post inoculation. Progression of the pathogen from the hypocotyl into the epicotyl of sunflower (systemic infection) was reduced by about one third in the presence of virus. In the virus containing strains, the average density of sporangia produced per cm² cotyledon reached only 75% of the virus-free controls. In summary, the presence of PhV leads to hypovirulence effects by weakening the aggressiveness of P. halstedii.

  20. Identification and functional analysis of downy mildew effectors in lettuce and Arabidopsis

    NARCIS (Netherlands)

    Stassen, J.H.M.|info:eu-repo/dai/nl/314004416

    2012-01-01

    Oomycete pathogens cause large losses in many crop plants. Chemical control measures are undesirable and are becoming less effective. Resistance breeding has traditionally made use of dominant resistance genes to which oomycete pathogens have often been quick to adapt. Novel approaches towards

  1. Risk assessment: progress of quarantine biocontrol research on Chinese Tallow, Melaleuca, and Downy Rose Myrtle

    Science.gov (United States)

    Risk assessments of two biocontrol candidates for Chinese tallow, Triadica sebifera (Euphoriales: Euphorbiaceae), and one for Melaleuca, Melaleuca quinquenervia (Myrtales: Myrtaceae), were conducted during 2009 and continuing into 2010 by USDA scientists located at the Florida Department of Agricul...

  2. Susceptibility of Arabidopsis to the downy mildew pathogen Hyaloperonospora parasitica : A reverse genetics approach

    NARCIS (Netherlands)

    de Jong, H.M.

    2008-01-01

    The research described in this thesis was performed to gain insight into disease susceptibility in the model system Arabidopsis thaliana – Hyaloperonospora parasitica. The aim was to identify host genes that support the infection process. For this, global expression profiling using DNA microarrays w

  3. First report of downy mildew caused by Peronospora sp. on Agastache in the United States

    Science.gov (United States)

    Hyssops (Agastache spp. and cultivars) are fragrant perennial plants in the mint family (Lamiaceae), primarily native to North America. Hybrid Agastache are bred as ornamental plants, valued for their showy flowers and aromatic scents that attract pollinators to the landscape. In May 2015, a commerc...

  4. Ecophysiological characteristics and cadmium accumulation in Downy Oak (Quercus pubescens Willd.

    Directory of Open Access Journals (Sweden)

    Cocozza C

    2012-10-01

    Full Text Available Heavy metals provoke environmental pollution with potentially toxic effects on human and plants systems. Recently, investigations are conducted on plants that may play a relevant role on pollutants absorption or stabilization, focusing on fast growing tree species in agronomic conditions; little is known on the effects of contaminants on tree species colonizing abandoned fields to be used in restoration ecology. The effects of Cd on photosynthetic performance and metal accumulation were investigated in Quercus pubescens Willd. seedlings grown in pots containing a mixture of sand, clay, turf and Cd-treatments (0, 25 and 75 mg kg-1 dry soil. The studied photosynthetic parameters (Asat= net phytosynthesis; Rday= day respiration; Γcomp= CO2 compensation point; Vcmax= maximum carboxylation rate; Jmax = electron transport rate; TPU = triose phosphate use; Ci/Ca = ratio of intercellular (Ci to ambient (Ca [CO2] (Ci/Ca; Jmax/Vcmax = ratio; (gsmax = maximum stomatal conductance; (lg = stomatal conductance estimated relative to the photosynthetic rate; (Fv/Fm = maximum quantum yield of PSII photochemistry; (ΔF/F’m = effective photochemical efficiency varied progressively with increasing Cd concentration in the soil, highlighting a negative impact on photosynthetic potential and PSII functioning. Approximately 10% of added Cd was found to be extractable from the substrate, at the maximum concentration applied, with about 12 and 0.75 as bioaccumulation and translocation factors, respectively. Analogously, Cd accumulated up to 34, 30 and 46 mg kg−1 in leaves, stem and roots, respectively. While it is not possible to extrapolate from the present study with seedlings to effects on mature pine trees, there are clear implications for regeneration in soils contaminated with heavy metals, which may lead to ecosystem deterioration.

  5. Registration of an oilseed sunflower germplasm HA-DM1 resistant to sunflower downy mildew

    Science.gov (United States)

    HA-DM1 (Reg. No.xxx, PI 674793) sunflower (Helianthus annuus L.) germplasm was developed and released cooperatively by the USDA-ARS, Sunflower and Plant Biology Research Unit and the North Dakota Agricultural Experiment Station in 2015. HA-DM1 is a BC2F4 derived oilseed maintainer line from the cros...

  6. Using high-resolution future climate scenarios to forecast Bromus tectorum invasion in Rocky Mountain National Park.

    Directory of Open Access Journals (Sweden)

    Amanda M West

    Full Text Available National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass, which is found in Rocky Mountain National Park (hereafter, the Park, Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211, current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2 and at a fine spatial resolution (90 m is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum.

  7. Using high-resolution future climate scenarios to forecast Bromus tectorum invasion in Rocky Mountain National Park.

    Science.gov (United States)

    West, Amanda M; Kumar, Sunil; Wakie, Tewodros; Brown, Cynthia S; Stohlgren, Thomas J; Laituri, Melinda; Bromberg, Jim

    2015-01-01

    National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil nitrogen, altered nutrient and hydrologic regimes, and increased fire intensity. We estimated the potential distribution of B. tectorum in the Park based on occurrence records (n = 211), current and future climate, and distance to roads and trails. An ensemble of six future climate scenarios indicated the habitable area of B. tectorum may increase from approximately 5.5% currently to 20.4% of the Park by the year 2050. Using ordination methods we evaluated the climatic space occupied by B. tectorum in the Park and how this space may shift given future climate change. Modeling climate change at a small extent (1,076 km2) and at a fine spatial resolution (90 m) is a novel approach in species distribution modeling, and may provide inference for microclimates not captured in coarse-scale models. Maps from our models serve as high-resolution hypotheses that can be improved over time by land managers to set priorities for surveys and removal of invasive species such as B. tectorum.

  8. Mapping genes in barley for resistance to Puccinia coronata from couch grass and to P. striiformis from brome, wheat and barley

    NARCIS (Netherlands)

    Niks, R.E.; Alemu, Sisay K.; Marcel, T.C.; Heyzen, van Skye

    2015-01-01

    Barley (Hordeum vulgare L.) mapping populations have been developed that are useful to study the inheritance of quantitative resistance to adapted and unadapted rust fungi. In a recent host range study, we found that the parents of those mapping populations also differed in their resistance to th

  9. Book title: Exotic brome grasses in arid and semi-arid ecosystems of the western US: causes, consequences, and management implications

    Science.gov (United States)

    Exotic invasive annual grass research and management in arid and semiarid ecosystems of the western US have historically focused on the outcome of efforts to reduce weed abundance. Given the current impact of invasive annual grasses and their continued spread in this region, we assessed components ...

  10. Verification of the systematic position of California brome (Bromus carinatus Hook. and Arn., Poaceae, cv. 'Broma', on the basis of analysis of issr markers

    Directory of Open Access Journals (Sweden)

    Agnieszka Sutkowska

    2012-10-01

    Full Text Available ‘Broma’ is a grass cultivar belonging to the species Bromus carinatus. In the Lists of Agricultural Plant Varieties of the Research Centre for Cultivar Testing (COBORU, it is shown as Bromus willdenowii (= B. catharticus, B. unioloides (List of Agricultural Plant Varieties 1989-2009, whereas already in 1984 Mirek demonstrated on the basis of morphological analysis that this was a different closely related species – B. carinatus. The aim of the present study was to verify the species affiliation of cv. ‘Broma’. The conducted analysis of ISSR molecular markers included representatives of cv. ‘Broma” as well as of B. carinatus and B. willdenowii. The method used allowed the identification of molecular markers of the above-mentioned taxa. The numerical analysis of the obtained results suggests that cv. ‘Broma’ should be classified in the species B. carinatus, not B. willdenowii.

  11. Isoprene emissions from downy oak under water limitation during an entire growing season: what cost for growth?

    Directory of Open Access Journals (Sweden)

    Anne-Cyrielle Genard-Zielinski

    Full Text Available Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C, mild and severe water stress (MS, SS. The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential functional (relative leaf water content, leaf mass per area ratio and growth (aerial and root biomass traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North Mediterranean areas are also discussed.

  12. Isoprene emissions from downy oak under water limitation during an entire growing season: what cost for growth?

    Science.gov (United States)

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North Mediterranean areas are also discussed.

  13. Distribution of downy mildew (Bremia Lactucae Regel) resistances in a genebank collection of lettuce and its wild relatives

    NARCIS (Netherlands)

    Treuren, van R.; Arend, van der A.J.M.; Schut, J.W.

    2013-01-01

    Genebanks serve as a rich source of diversity that can be exploited for crop improvement. However, large numbers of accessions usually have to be evaluated to find material with the characters of interest, and therefore, enhanced trait information can facilitate the more efficient selection of acces

  14. QTL identification in an interspecific grapevine cross segregating for resistance to Powdery Mildew, Downy Mildew, Black Rot, and Phylloxera

    Science.gov (United States)

    Grapevine is a highly heterozygous plant with a complex genetic background. Here, we report the use of an F1 family (N = 125) from a cross of MN1264 × MN1246 made in 2010. The cross contains at least six Vitis species in its ancestry and segregates for resistance to powdery mildew (Erysiphe necator)...

  15. Computing Integrated Ratings from Heterogeneous Phenotypic Assessments: A Case Study of Lettuce Postharvest Quality and Downy Mildew Resistance

    Science.gov (United States)

    Comparing performance of a large number of accessions simultaneously is not always possible. Typically, only subsets of all accessions are tested in separate trials with only some (or none) of the accessions overlapping between subsets. Using standard statistical approaches to combine data from such...

  16. Preliminary Trial of 11 New Hybrid Maize Genotype to The Resistance on Java Downy Mildew (Peronosclerospora maydis)

    OpenAIRE

    Budi Setyawan; Irfan Suliansyah; Aswaldi Anwar; Etti Swasti

    2016-01-01

    Maize or corn (Zea mays L.) belongs to the family of grasses (Poaceae).  Maize is grown globally and one of the most important cereal crop in the world.  In many countries, corn is the main agricultural crop, and are used as food, feed and industrial raw materials. Together with rice and wheat, corn included in the cereals that provide about 65% carbohydrates and 50% protein that humans need. For this purpose, many developing countries, especially in Asia and Africa are in a strong effort to ...

  17. Interacting agricultural pests and their effect on crop yield: application of a Bayesian decision theory approach to the joint management of Bromus tectorum and Cephus cinctus.

    Directory of Open Access Journals (Sweden)

    Ilai N Keren

    Full Text Available Worldwide, the landscape homogeneity of extensive monocultures that characterizes conventional agriculture has resulted in the development of specialized and interacting multitrophic pest complexes. While integrated pest management emphasizes the need to consider the ecological context where multiple species coexist, management recommendations are often based on single-species tactics. This approach may not provide satisfactory solutions when confronted with the complex interactions occurring between organisms at the same or different trophic levels. Replacement of the single-species management model with more sophisticated, multi-species programs requires an understanding of the direct and indirect interactions occurring between the crop and all categories of pests. We evaluated a modeling framework to make multi-pest management decisions taking into account direct and indirect interactions among species belonging to different trophic levels. We adopted a Bayesian decision theory approach in combination with path analysis to evaluate interactions between Bromus tectorum (downy brome, cheatgrass and Cephus cinctus (wheat stem sawfly in wheat (Triticum aestivum systems. We assessed their joint responses to weed management tactics, seeding rates, and cultivar tolerance to insect stem boring or competition. Our results indicated that C. cinctus oviposition behavior varied as a function of B. tectorum pressure. Crop responses were more readily explained by the joint effects of management tactics on both categories of pests and their interactions than just by the direct impact of any particular management scheme on yield. In accordance, a C. cinctus tolerant variety should be planted at a low seeding rate under high insect pressure. However as B. tectorum levels increase, the C. cinctus tolerant variety should be replaced by a competitive and drought tolerant cultivar at high seeding rates despite C. cinctus infestation. This study exemplifies the

  18. Diel Patterns of Colaspis brunnea and Colaspis crinicornis (Coleoptera: Chrysomelidae) in Southeastern Nebraska.

    Science.gov (United States)

    Miwa, Kentaro; Meinke, Lance J

    2015-12-01

    A field study was conducted to increase our understanding of diel activity patterns of Colaspis brunnea (F.) and Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) in key crop habitats. Within 24-h periods, C. brunnea was sampled in clover fields (primarily red clover, Trifolium pretense (L.), with some sweet clover, Melilotus officinalis (L.) Pallas, and downy brome, Bromus tectorum (L.)) and soybean, Glycine max (L.) Merrill, fields, using a sweep-net, while whole-plant-count sampling was used to monitor C. crinicornis densities in field corn, Zea mays (L.). Sweep-net captures of C. brunnea were significantly greater at night than during the day, suggesting possible vertical movement within the canopy during a 24-h period. Colaspis crinicornis densities on corn plants were fairly constant throughout a 24-h period, but beetle activity (e.g., walking, mating) was significantly greater at night than during the day. Results suggest that both Colaspis species may be exhibiting similar increases in activity at night that facilitates movement from more protected to more exposed areas within a habitat. It is unclear what mechanisms drive this diel pattern, but vegetation architecture and associated interactions with environmental conditions may play a role. Sweep-netting in clover or soybean fields and use of whole-plant-counts in cornfields were effective sampling methods for Colaspis adults. However, because activity and behaviors of Colaspis beetles were influenced by time of day in this study, use of a consistent sampling time within a diel period would be recommended for future population studies or integrated pest management decision-making.

  19. Environmental Assessment: Proposed Lakeview Marina Site Boat Ramp and Access, Saylorville Lake, Polk County, Iowa

    Science.gov (United States)

    1988-08-01

    cover of yellow sweet clover, red clover, and a small amount of brome grass ( Bromus sp.). Trees within the upper zone include sapling and intermediate...clover, brome grass , and switchgrass ( Paspalum virgatum) with small amounts of goldenrod (Solidago sp.) poison ivy, milkweed (Amaranthus sp.), thistle...amount of brome grass ( Bromus sp.). Trees within the upper zone include sapling and intermediate size shagbark hickory, sumac (Rhus glabra), and white

  20. The subgenomic promoter of brome mosaic virus folds into a stem-loop structure capped by a pseudo-triloop that is structurally similar to the triloop of the genomic promoter

    DEFF Research Database (Denmark)

    Skov, J.; Gaudin, M.; Podbevsek, P.;

    2012-01-01

    region of the (+)-RNA strands. Two alternate hypotheses have been put forward for the mechanism of subgenomic RNA transcription. One posits that transcription commences by recognition of at least four key nucleotides in the subgenomic promoter by the replicase. The other posits that subgenomic...... transcription starts by binding of the replicase to a hairpin formed by the subgenomic promoter that resembles the minus strand promoter hairpin SLC. In this study, we have determined the three-dimensional structure of the subgenomic promoter hairpin using NMR spectroscopy. The data show that the hairpin......, including the formation of a so-called clamped-adenine motif. The similarities of the NMR structures of the hairpins required for genomic RNA and subgenomic RNA synthesis show that the replicase recognizes structure rather than sequence-specific motifs in both promoters....

  1. 基于MaxEnt的农田恶性杂草雀麦的潜在分布预测%Prediction of Potential Distribution of Japanese Brome (Bromus japonicus) Based on MaxEnt

    Institute of Scientific and Technical Information of China (English)

    谭金妮; 李琦; 白霜; 王金信

    2016-01-01

    雀麦是中国农田一种恶性杂草,危害作物生长和发育.为控制其进一步扩散蔓延,根据目前雀麦在全球的分布记录和气象数据,利用最大熵模型MaxEnt和ArcGIS对雀麦在中国和全球的潜在适生区域进行预测和分析.预测结果表明:雀麦在全球的适生区为非洲北部、欧洲的中南部、亚洲西部和东部及中部零星地区、北美中西部及东部部分地区、日本及朝鲜南部地区;在中国主要在黄淮海平原、长江中下游平原、成都平原、陕西中南部、山西南部、宁夏及甘肃南部、贵州中北部、新疆西南零星地区、西藏西南部及青海中部地区分布;中风险潜在分布区域的范围在高风险区的基础上进一步扩大.环境变量中对雀麦发生影响较大的是最冷季度平均温度、年平均气温、温度季节性变化标准差、最冷月最低温、最干季度平均温度.本研究的AUC值为0.943,模拟预测准确性极好,模拟结果可以用于雀麦的适生区预测研究.

  2. Selection pressure exerted by host resistance genes shapes the population genetic structure of the lettuce downy mildew, Bremia lactucae, in France

    OpenAIRE

    Valade, Romain; Ducasse, Aurélie; Maisonneuve, Brigitte; Neema, Claire,

    2012-01-01

    Most pathogens are submitted to high selection pressure which can be induced by several variables (climatic, biotic, anthropogenicoe) according to their life traits. In the case of plant pathogens, host resistance may be considered as the main driving force of pathogen evolution, with pathogens evolving to overcome host resistance. In the interaction between Bremia lactucae and Lactuca sativa, several specific resistance genes are used to counter this pathogen in crops. In turn, pathogens sho...

  3. A comparison of Peronospora parasitica (Downy mildew) isolates from Arabidopsis thaliana and Brassica oleracea using amplified fragment length polymorphism and internal transcribed spacer 1 sequence analyses.

    Science.gov (United States)

    Rehmany, A P; Lynn, J R; Tör, M; Holub, E B; Beynon, J L

    2000-07-01

    Amplified fragment length polymorphism (AFLP) fingerprints and internal transcribed spacer 1 (ITS1) sequences from 27 Peronospora parasitica isolates (collected from Arabidopsis thaliana or Brassica oleracea), 5 Albugo candida isolates (from the same hosts and from Capsella bursa-pastoris), and 1 Bremia lactucae isolate (from Lactuca sativa) were compared. The AFLP analysis divided the isolates into five groups that correlated with taxonomic species and, in most cases, with host origin. The only exception was a group consisting of A. candida isolates from both B. oleracea and C. bursa-pastoris. ITS1 sequence analysis divided the isolates into the same five groups, demonstrated the divergence between P. parasitica isolates from A. thaliana and B. oleracea, and, using previously published ITS1 sequences, clearly showed the relationship between A. candida isolates from different hosts.

  4. Use of chitosan against downy mildew of rose%几丁聚糖控制月季霜霉病的研究

    Institute of Scientific and Technical Information of China (English)

    孙彤

    2002-01-01

    几丁聚糖是几丁质脱乙酰基后得到的一种氨基多糖.其产品0.5%OS-施特灵可控制月季霜霉病Peronospora sparsa,每隔10天以500倍液连续施药3次,控制效果达80%左右.

  5. Efeito de indutores no controle de míldio em Vitis labrusca Effect of elicitors in the control of downy mildew in Vitis labrusca

    OpenAIRE

    Regina Ceres Torres da Rosa; Rildo Sartori Barbosa Coelho; Selma Cavalcante Cruz de Holanda Tavares; Vanildo Alberto Leal Bezerra Cavalcanti

    2007-01-01

    A cultura da uva, Vitis labrusca, é de grande importância econômica para a região do vale do Siriji - PE. No entanto, nos últimos anos, o míldio da videira vem pondo em risco essa atividade, fazendo com que os produtores invistam bastante recurso com o uso de fungicida visando o seu controle. Visando substituir o uso de agrotóxico foi avaliado nos municípios de São Vicente Férrer - PE (área 1), Natuba - PB (área 2) e Macaparana - PE (área 3) o efeito da indução de resistência promovida por ác...

  6. Arbuscular mycorrhizal symbiosis stimulates key genes of the phenylpropanoid biosynthesis and stilbenoid production in grapevine leaves in response to downy mildew and grey mould infection.

    Science.gov (United States)

    Bruisson, Sébastien; Maillot, Pascale; Schellenbaum, Paul; Walter, Bernard; Gindro, Katia; Deglène-Benbrahim, Laurence

    2016-11-01

    Grapevine (Vitis spp) is susceptible to serious fungal diseases usually controlled by chemical treatments. Arbuscular mycorrhizal fungi (AMF) are obligate plant symbionts which can stimulate plant defences. We investigated the effect of mycorrhization on grapevine stilbenoid defences. Vitis vinifera cvs Chasselas, Pinot noir and the interspecific hybrid Divico, on the rootstock 41B, were mycorrhized with Rhizophagus irregularis before leaf infection by Plasmopara viticola or Botrytis cinerea. Gene expression analysis showed an up-regulation of PAL, STS, and ROMT, involved in the stilbenoid biosynthesis pathway, in plant leaves, 48 h after pathogen inoculation. This defense response could be potentiated under AMF colonization, with an intensity level depending on the gene, the plant cultivar and/or the pathogen. We also showed that higher amounts of active forms of stilbenoids (i.e trans-form of resveratrol, ε- and δ-viniferins and pterostilbene) were produced in mycorrhized plants of the three genotypes in comparison with non-mycorrhized ones, 10 days post-inoculation with either pathogen. These results support the hypothesis that AMF root colonization enhances defence reactions against a biotrophic and a necrotrophic pathogen, in the aerial parts of grapevine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Characterization of a hydroxyproline-rich glycoprotein in pearl millet and its differential expression in response to the downy mildew pathogen Sclerospora graminicola

    NARCIS (Netherlands)

    Sujeeth, Neerakkal; Kini, Ramachandra K.; Shailasree, Sekhar; Wallaart, Eelco; Shetty, Shekar H.; Hille, Jacques; Barna, B.

    2012-01-01

    A monoclonal antibody, JIM 20, derived against an extensin type of hydroxyproline-rich glycoprotein (HRGP) from pea, showed high affinity for HRGP in pearl millet [Pennisetum glaucum (L.) R. Br.]. Electrophoretic separation of Tris-SDS extracted proteins from suspension cells of pearl millet reveale

  8. Downy mildew (Peronospora parasitica) resistance genes in Arabidopsis vary in functional requirements for NDR1, EDS1, NPR1 and salicylic acid accumulation.

    Science.gov (United States)

    McDowell, J M; Cuzick, A; Can, C; Beynon, J; Dangl, J L; Holub, E B

    2000-06-01

    To better understand the genetic requirements for R gene-dependent defense activation in Arabidopsis, we tested the effect of several defense response mutants on resistance specified by eight RPP genes (for resistance to Peronospora parasitica) expressed in the Col-0 background. In most cases, resistance was not suppressed by a mutation in the SAR regulatory gene NPR1 or by expression of the NahG transgene. Thus, salicylic acid accumulation and NPR1 function are not necessary for resistance mediated by these RPP genes. In addition, resistance conferred by two of these genes, RPP7 and RPP8, was not significantly suppressed by mutations in either EDS1 or NDR1. RPP7 resistance was also not compromised by mutations in EIN2, JAR1 or COI1 which affect ethylene or jasmonic acid signaling. Double mutants were therefore tested. RPP7 and RPP8 were weakly suppressed in an eds1-2/ndr1-1 background, suggesting that these RPP genes operate additively through EDS1, NDR1 and as-yet-undefined signaling components. RPP7 was not compromised in coi1/npr1 or coi1/NahG backgrounds. These observations suggest that RPP7 initiates resistance through a novel signaling pathway that functions independently of salicylic acid accumulation or jasmonic acid response components.

  9. The Arabidopsis downy mildew resistance gene, RPP13-Nd, functions independently of NDR1 and EDS1 and does not require the accumulation of salicylic acid.

    Science.gov (United States)

    Bittner-Eddy, P D; Beynon, J L

    2001-03-01

    RPP13-Nd-mediated resistance prevents parasitism by five isolates of Peronospora parasitica (At) in a transgenic Arabidopsis. Columbia background. We tested the effect of a number of known disease resistance mutations on the RPP13-Nd function and found that resistance remained unaltered in plants carrying mutations in either EDS1 or NDR1 and in double ndr1-1/eds1-2 mutant lines. Furthermore, we found that pbs2, pad4-1, npr1-1, and rps5-1, which compromise resistance to a number of P. parasitica (At) isolates, had no affect on RPP13-Nd function. In addition, RPP13-Nd-mediated resistance remained unchanged in a background of salicylic acid depletion (nahG). We conclude that RPP13-Nd is the first Arabidopsis R gene product reported to act via a novel signaling pathway that is independent of salicylic acid-mediated responses and is completely independent of NDR1 and EDS1.

  10. Implications of Farmers' Propensity to Discontinue Adoption of Downy-Mildew Resistant Maize and Improved Cowpea Varieties for Extension Education in Southwestern Nigeria

    Science.gov (United States)

    Oladele, O. I.; Adekoya, A. E.

    2006-01-01

    This paper examines the implications of farmers' propensity to discontinue the adoption of agricultural technologies in southwestern Nigeria. This is predicated on the fact that extension education process should be proactive in addressing farmers in order to sustain the adoption process. Empirical studies looking at diffusion processes from an…

  11. 40 CFR 180.34 - Tests on the amount of residue remaining.

    Science.gov (United States)

    2010-07-01

    ...) Carrots, garden beets, sugar beets, horseradish, parsnips, radishes, rutabagas, salsify roots, turnips..., barley, oats, rice, rye (each in grain form). (25) Alfalfa, Bermuda grass, bluegrass, brome...

  12. Recommended Species for Vegetative Stabilization of Training Lands in Arid and Semi-Arid Environments

    Science.gov (United States)

    1985-09-01

    semibacata Awnless bush sunflower Helianthus sp. Bahia grass Paspalum notatum Barley Hordeum vulgare Basin wildrye Elymus cinereus Bearded wheatgrass...Boer lovegrass Eragrostis curvuLa *Brittlebush Encelia farinosa *Brome grasses Bromus spp. Buckwheat s Eriogonum spp. Buffalograss Buchloe dactyloides...mexicana *Millets Panicum spp. Mountain brome Bromus montanum Mountain mahogany Gercocarpus montanus *Mountain penstenion Penstemon montanus *Muhly grasses

  13. Recognition of Cucumber Downy Mildew Disease Based on Visual Saliency Map%基于视觉显著性图的黄瓜霜霉病识别方法

    Institute of Scientific and Technical Information of China (English)

    叶海建; 郎睿; 刘成启; 李民赞

    2016-01-01

    为提高黄瓜霜霉病叶部病害机器自动识别的准确性和鲁棒性,提出了一种基于视觉显著性图的黄瓜叶部霜霉病识别方法.首先将图像从RGB色彩空间变换到HSV色彩空间中进行色彩修正,再变换回RGB空间利用R、G、B分量的线性组合生成视觉显著性图,最后通过对生成的视觉显著性图进行阈值分割以识别病害区域.利用从北京市北部郊区日光温室采集到的50幅具有典型霜霉病特征的黄瓜叶片原始图像进行实验,结果表明,该方法能较为准确地从叶部彩色图像中识别出霜霉病病斑区域,平均误分率为6.98%,优于K-means法(11.38%)和OTSU法(15.98%);平均运行时间0.661 4s,少于K-means法的1.424 9 s;运行时间的均方根误差为0.051 5 s,鲁棒性优于K-means硬聚类算法.

  14. Preventive Effect of 20 Plant Extracts against Cucumber Downy Mildew%20种植物提取液对黄瓜霜霉病的预防作用研究

    Institute of Scientific and Technical Information of China (English)

    赵杰; 代光辉; 顾振芳; 陈晓斌; 孙兴全

    2005-01-01

    用叶圆盘生测法测定了20种植物不同组织部位的甲醇提取液对黄瓜霜霉病菌(Pseudoperonospora cubehsis)的抑茵效果,其中水蓼(Polygonum hydropiper L.)全草,合欢(Albizia julibrissin Durazz.)叶和石楠(Photinia serrulata Lindl.)枝的甲醇提取液在离体叶圆盘的防效分别为98.33%,100.00%和100.00%,其它植物提取液均无明显抑茵效果.上述3种植物提取液的室内盆栽试验结果表明,7天后对黄瓜霜霉病的预防效果分别为54.19%,62.00%和78.93%,田间试验的防效则分别为25.57%,27.91%和48.84%.对防效较好的石楠枝甲醇提取物用石油醚、乙酸乙酯、水饱和正丁醇依次进行萃取,并对各萃取物进行叶圆盘测定,结果表明,有效活性成分存在于正丁醇相和水相中;当浓度为30mg·ml-1时,两相萃取物对黄瓜霜霉病的抑制率分别为100.00%和87.87%.

  15. 6种候选杀菌剂对黄瓜霜霉病的防治效果%Control Efficacy of Six Candidate Fungicides against Cucumber Downy Mildew

    Institute of Scientific and Technical Information of China (English)

    乔桂双; 王文桥; 韩秀英; 李淼; 孟润杰; 刘长令; 刘颖超

    2009-01-01

    室内及田间试验结果表明:20%SYP-3399 SC、20%SYP-4155 EC、20%SYP-3343 SC对黄瓜霜霉病的防效较为突出.20%SYP-4155 EC(150 g a.i./hm 2)、20%SYP-3343 SC(150 g a.i./hm2)、20%SYP-3399 SC(900 g a.i./hm2)的防效与25%嘧菌脂SC(100 g a.i./hm2)、72%霜脲氰·代森锰锌WP(1 440 g a.i./hm2)防效相当,高于68%精甲霜灵·代森锰锌WG(675 g a.i./hm2)、25%吡唑醚菌酯EC(100 g a.i./hm2)的防效.3种候选杀菌剂在试验剂最范同内对作物安全.

  16. Willamette Valley - Invasive Species Management with Volunteers 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Volunteers worked with refuge staff to survey for and treat invasive species on the Willamette Valley Refuges (Ankeny, Baskett Slough and WL Finley NWR). False brome...

  17. Yeast Interacting Proteins Database: YCR095C, YNL099C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available S. cerevisiae, which is a model system for studying replication of positive-strand RNA viruses in their natu...on of Brome mosaic virus in S. cerevisiae, which is a model system for studying r

  18. American River Watershed Investigation, California, Feasibility Report. Part 1. Main Report. Part 2. Environmental Impact Statement/Environmental Impact Report

    Science.gov (United States)

    1991-12-01

    oak Avena fatua X X X Datlis grass Paspalum dilatatum X X Red brome Bromus rubra X X X Botttebrush squirrettaiL Sitanion hystrix X X X Notes: OAK...Continuied) COIWOM MANE SCIENTIFIC NME TYPICAL COIMJNITY Wild oats Avena fatua GRASS Crab grass Digitaria sanguinatis GRASS Brome grass Bromus rubens GRASS ...River. The Auburn area is generally developed, with heavy traffic volumes passing along Interstate 80 and northward along Highway 49 to Grass Valley

  19. Studying the possibility of dehairing coarse sheep wool

    Directory of Open Access Journals (Sweden)

    Murat Otynshiyev

    2013-03-01

    Full Text Available The article considers the development of complex technology of advanced processing of coarse and medium sheep wool that enables the production of new types of woolen products such as downy fiber and from downy fiber various semi-finished and finished products. Investigations of technological processes of primary and advanced processing of untrue coarse and medium wool are carried out and wool sorting, wool washing, and obtaining downy fiber from wool on the basis of coarse wool fiber pulling on carding machines are the stages of processing the wool.

  20. Archaea and bacteria mediate the effects of native species root loss on fungi during plant invasion.

    Science.gov (United States)

    Mamet, Steven D; Lamb, Eric G; Piper, Candace L; Winsley, Tristrom; Siciliano, Steven D

    2017-05-01

    Although invasive plants can drive ecosystem change, little is known about the directional nature of belowground interactions between invasive plants, native roots, bacteria, archaea and fungi. We used detailed bioinformatics and a recently developed root assay on soils collected in fescue grassland along a gradient of smooth brome (Bromus inermis Leyss) invasion to examine the links between smooth brome shoot litter and root, archaea, bacteria and fungal communities. We examined (1) aboveground versus belowground influences of smooth brome on soil microbial communities, (2) the importance of direct versus microbe-mediated impacts of plants on soil fungal communities, and (3) the web of roots, shoots, archaea, bacteria and fungi interactions across the A and B soil horizons in invaded and non-invaded sites. Archaea and bacteria influenced fungal composition, but not vice versa, as indicated by redundancy analyses. Co-inertia analyses suggested that bacterial-fungal variance was driven primarily by 12 bacterial operational taxonomic units (OTUs). Brome increased bacterial diversity via smooth brome litter in the A horizon and roots in the B horizon, which then reduced fungal diversity. Archaea increased abundance of several bacterial OTUs, and the key bacterial OTUs mediated changes in the fungi's response to invasion. Overall, native root diversity loss and bacterial mediation were more important drivers of fungal composition than were the direct effects of increases in smooth brome. Critically, native plant species displacement and root loss appeared to be the most important driver of fungal composition during invasion. This causal web likely gives rise to the plant-fungi feedbacks, which are an essential factor determining plant diversity in invaded grassland ecosystems.

  1. U.S. Fresh and Pickling Cucumber Markets

    OpenAIRE

    2013-01-01

    As part of an effort to estimate the potential impact of downy mildew to U.S. growers of cucumbers, this report reviews historical trends in production and markets for cucumbers including slicing and pickling cucumbers.

  2. Foreword: Special issue on fungal grapevine diseases

    Science.gov (United States)

    An impressively large proportion of fungicides applied in European, North American and Australian agriculture has been used to manage grapevine powdery mildew (Erysiphe necator), grapevine downy mildew (Plasmopara viticola), and botrytis bunch rot (Botrytis cinerea). These fungal and oomycetous plan...

  3. Silencing of the major family of NBS-LRR-encoding genes in lettuce results in the loss of multiple resistance specificities

    National Research Council Canada - National Science Library

    Wroblewski, T; Piskurewicz, U; Finkers-Tomczak, A.M; Ochoa, O; Michelmore, R

    2007-01-01

    ...¿leucine-rich repeat (NBS¿LRR) proteins. One of its members, RGC2B, encodes Dm3 which determines resistance to downy mildew caused by the oomycete Bremia lactucae carrying the cognate avirulence gene, Avr3...

  4. An evaluation of a refresher training intervention for HIV lay ...

    African Journals Online (AJOL)

    Charles Msisuka a , Ikuma Nozaki b i-nozaki@it.ncgm.go.jpinozaki@hsph.harvard.edu, Kazuhiro Kakimoto c , Motoko Seko d & Mercy M S Ulaya e

    Motoko Seko is a Technical Consultant for Japan International Cooperation Agency (JICA), Japan. She was ..... (92%) answered that lack of incentives is major challenge, 13 (52%) responded .... from http://www.zamstats.gov.zm/. Downie, J.

  5. Potassium Bicarbonate as a Potential Sulphur Substitute in Protected Organic Cropping

    OpenAIRE

    Koller, Martin

    2011-01-01

    Powdery mildew attacks several important crops in greenhouses (e.g. tomatoes, cucumbers). Compared to other airborne pathogens, such as downy mildews (e.g. Pseudoperonospora cubensis or Phytophthora infestans) or Botrytis, the damage is often not very severe. However, an effective control of powdery mildew with organic fungicides gives the possibility to optimize climate conditions to also prevent downy mildews and gray mold. Sulphur, a well established fungicide, is rated as slightly to very...

  6. Efecto del Fosfito de Potasio en Combinación con el Fungicida Metalaxyl + Mancozeb en el Control de Mildeo Velloso (Peronospora destructor Berk en Cebolla de Bulbo (Allium cepa L. Effect of the Potasium Phosphite in Combination with the Fungicide Metalaxyl plus Mancozeb on the Control of Downy Mildew (Peronospora destructor Berk in Onion Bulb (Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Jorge Velandia Monsalve

    2012-06-01

    Full Text Available Resumen. El hongo Peronospora destructor causa considerables pérdidas en la producción de cebolla de bulbo en el mundo. Fosfito de potasio en combinación con el fungicida Metalaxyl + Mancozeb, fue evaluado por su eficiencia en el control de este patógeno en el híbrido de cebolla de bulbo Yellow Granex. Los tratamientos consistieron en una aplicación de fosfito (5 mL L-1 alternada con una de fungicida (2 g L-1; dos y tres aplicaciones consecutivas de fosfito alternadas con una de fungicida; una aplicación de fungicida alternada con una de fosfito; dos y tres aplicaciones consecutivas de fungicida alternadas con una de fosfito; aplicaciones de sólo fosfito y sólo fungicida y un testigo. Se utilizó el diseño experimental de bloques completos al azar con tres repeticiones. Se evaluó la incidencia y severidad de la enfermedad, el número, tamaño y peso de bulbos de primera, segunda, tercera y peso total de bulbos. Los resultados mostraron que las aplicaciones de fosfito de potasio durante dos semanas consecutivas alternadas en la tercera semana con una de fungicida y las aplicaciones semanales de sólo fosfito, tuvieron efectos altamente significativos en el control de la incidencia y severidad de P. destructor y diferencias significativas en el peso de los bulbos de primera (28,1 y 27,9 t ha-1 y peso total de bulbos (55,5 y 52,1 t ha-1, representando en relación al testigo, un incremento de 200 y 196% en el peso de los bulbos de primera y de 55 y 45,7% en el peso total de bulbos, respectivamente. Se concluye que con el fosfito de potasio se reduce la aplicación de fungicidas y ello es una alternativa viable para el manejo ecológico de P. destructor en la producción de cebolla de bulbo.Abstract. Peronospora destructor fungi causes considerable loses in the production of onion bulb in the world. Potassium phosphite in combination with the fungicide Metalaxyl + Mancozeb was evaluated for its efficiency in the control of this pathogen in the onion bulb hybrid Yellow Granex. The treatments consisted in one application of potassium phosphite (5 mL L-1 alternated with one of fungicide (2 g L-1; two and three consecutive applications of potassium phosphite alternated with one of fungicide; one application of fungicide alternated with one of potassium phosphite; two and three consecutive applications of fungicide alternated with one of potassium phosphite; applications of potassium phosphite and fungicide alone and one control. The experimental design was a complete block randomized with three replicates. The variables evaluated were the incidence and severity of the disease and the number, size and weight of the bulbs of first, second and third class and total bulb weight. The results showed that the applications of potassium phosphite during two consecutive weeks alternated in the third week with one of fungicide and the weekly applications of phosphite alone had highly significant effects on the control of the incidence and severity of P. destructor and significant differences on the weight of the first class bulbs (28.1 and 27.9 t ha-1 and total bulb weight (55.5 and 52.1 t ha-1, representing in comparison to the control an increment of 200 and 196% on the weight of the first class bulbs and of 55 and 45,7% on the total bulb weight, respectively. It is concluded that with the potassium phosphite the application of fungicides is reduced and this represents a viable alternative for the ecological management of P. destructor in the production of onion bulb.

  7. Aplicação foliar de tratamentos para o controle do míldio e da podridão-de-escamas de bulbos de cebola Foliar spray of treatments in the control of downy mildew and bulb rot in onion

    OpenAIRE

    João Américo Wordell Filho; Martins,Daniel A; Marciel J. Stadnik

    2007-01-01

    Em experimento de campo, avaliou-se o efeito da aplicação foliar de tratamentos para o controle do míldio (Peronospora destructor) e da podridão de bulbos (Burkholderia cepacia) de cebola: testemunha, clorotalonil/metalaxyl + clorotalonil, fosfito de potássio, fertilizante foliar (03-00-16, N-P-K), calda bordalesa, calda bordalesa/fosfito de potássio, acibenzolar-S-methyl, pulverizados semanalmente; extrato de alga (Ulva fasciata) e ulvana, aplicados a cada 7, 14 e 21 dias. Somente a pulveriz...

  8. Younger Adults Derive Pleasure and Utilitarian Benefits from Browsing for Music Information Seeking in Physical and Digital Spaces. A Review of: Laplante, A., & Downie, J. S. (2011. The utilitarian and hedonic outcomes of music information-seeking in everyday life. Library & Information Science Research, 33, 202-210. doi:10.1016/j.lisr.2010.11.002

    Directory of Open Access Journals (Sweden)

    Diana K. Wakimoto

    2012-09-01

    Full Text Available Objective – This study’s objective was to identify the utilitarian and hedonic features of satisfying music information seeking experiences from the perspective of younger adults when using physical and digital music information retrieval (MIR systems in their daily lives.Design – In-depth, semi-structured interviews.Setting – Large public library in Montreal, Canada.Subjects – 15 French-speaking younger adults,10 males and 5 females (aged 18 to 29 years, mean age of 24 years.Methods – A pre-test was completed to test the interview guide. The guide was dividedinto five sections asking the participants questions about their music tastes, how music fit into their daily lives, how they discovered music, what music information sources were used and how they were used, what made their experiences satisfying, and theirbiographical information. Participants were recruited between April 1, 2006 and August 8,2007 following maximum variation samplingfor the main study. Recruitment stopped whendata saturation was reached and no new themes arose during analysis. Interviews were recorded and the transcripts were analyzed via constant comparative method (CCM to determine themes and patterns. Main Results – The researchers found that both utilitarian and hedonic factors contributed to satisfaction with music information seeking experiences for the young adults. Utilitarian factors were divided between two main categories: finding music and finding information about music. Finding information about music could be further divided into three sub-categories: increasing cultural knowledge and social acceptance through increased knowledge about music, enriching the listening experience by finding information about the artist and the music, and gathering information to help with future music purchases including information that would help the participants recommend music to others. Hedonic outcomes that contributed to satisfying information seeking experiences included deriving pleasure and feeling engaged while searching or browsing for music. Especially satisfying experiences were those where the participants felt highly engaged in the process and found new, independent, non-mainstream music. Not finding new music did not automatically lead to an unsatisfying experience for the participants; however, technology malfunctions in digital MIR systems and unpleasant environments such as those with unfriendly staff in physical music spaces (libraries and stores, led to unsatisfying experiences for the participants.Conclusions – As the results show that the hedonic aspects of music information seeking are very important, designers of MIR systems must take into account the hedonic as well as utilitarian outcomes when creating user interfaces. MIR systems should be designed with browsing as well as searching capabilities so searchers can make serendipitous discoveries of new music and information about music. In other words, MIR systems need to be engaging to ensure satisfying interactions for searchers.

  9. Final Environmental Assessment: Proposed Laser-Firing Tank Range and Artillery Maneuver Area Arnold Air Force Base Tullahoma Tennessee

    Science.gov (United States)

    2005-03-01

    hispidus* hairy jointgrass Significant Bromus japonicus Japanese bromegrass Significant Bromus secalinus Rye brome Significant Carduus nutans Musk ... thistle Significant Clematis ternifolia Leatherleaf clematis Significant Coronilla varia Crown vetch Significant Daucus carota Queen Anne’s-lace...eliminated. Procedures would include identification and use of areas for maneuvers that would be least likely to be disturbed by vehicular traffic, as well

  10. Ecology, genetics, and biological control of invasive annual grasses in the Great Basin

    Science.gov (United States)

    Several annual grass species native to Eurasia, including cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) have become invasive in the western USA. These invasive species degrade rangelands by compromising forage, outcompeting native flora, and exacerb...

  11. Soil sulfur amendments suppress Selenium uptake by alfalfa and western wheatgrass

    Science.gov (United States)

    C. L. Mackowiak; M. C. Amacher

    2008-01-01

    Selenium (Se) is a potential soil contaminant in many parts of the world where it can pose a health risk to livestock and wildlife. Phosphate ore mining in Southeast Idaho has resulted in numerous waste rock dumps revegetated with forages to stabilize the dumps and support grazing. Alfalfa (Medicago sativa L.), smooth brome (Bromus inermis...

  12. Sequence Classification: 893308 [

    Lifescience Database Archive (English)

    Full Text Available nown function; deletion inhibits Brome mosaic virus expression; Elf1p || http://www.ncbi.nlm.nih.gov/protein/6322689 ... ...Non-TMB Non-TMH TMB Non-TMB TMB Non-TMB >gi|6322689|ref|NP_012762.1| Protein of unk

  13. Proposed Land Conveyance for Construction of Three Facilities at March Air Force Base, California

    Science.gov (United States)

    1988-09-01

    found. The species composition of this community includes grasses such as slender wild oat (Avena barbata), red brome ( Bromus rubens), foxtail...Hordeum sp.), ripgutgrass ( Bromus diandrus), and Schismus barbatus. Native bunch grasses of the undisturbed valley grassland community, such as needle...the southwestern part of the land, dominated by Dallis grass ( Paspalum dilatatum). The central, previously developed area consists of various

  14. Environmental Assessment: BRAC Construction and Operation of Armed Forces Reserve Center at Malmstrom Air Force Base, Great Falls, Montana

    Science.gov (United States)

    2009-06-01

    Medicago sativa ) (USAF, 2007). Approximately 36 acres of wet areas and moist seeps have been identified on Malmstrom AFB and range from retained...grazing lands is predominantly crested wheatgrass, with areas of smooth brome (Bromus inermis) and alfalfa ( Medicago sativa ) (USAF, 2007). MALMSTROM

  15. Do co-occurring plant species adapt to one another? The response of Bromus erectus to the presence of different Thymus vulgaris chemotypes.

    Science.gov (United States)

    Ehlers, Bodil K; Thompson, John

    2004-11-01

    Local modification of the soil environment by individual plants may affect the performance and composition of associated plant species. The aromatic plant Thymus vulgaris has the potential to modify the soil through leaching of water-soluble compounds from leaves and litter decomposition. In southern France, six different thyme chemotypes can be distinguished based on the dominant monoterpene in the essential oil, which is either phenolic or non-phenolic in structure. We examine how soils from within and away from thyme patches in sites dominated by either phenolic or non-phenolic chemotypes affect germination, growth and reproduction of the associated grass species Bromus erectus. To do so, we collected seeds of B. erectus from three phenolic and three non-phenolic sites. Seeds and seedlings were grown on soils from these sites in a reciprocal transplant type experiment in the glasshouse. Brome of non-phenolic origin performed significantly better on its home soil than on soil from a different non-phenolic or a phenolic site. This response to local chemotypes was only observed on soil collected directly underneath thyme plants and not on soil in the same site (<5 m away) but where no thyme plants were present. This is preliminary evidence that brome plants show an adaptive response to soil modifications mediated by the local thyme chemotypes. Reproductive effort was consistently higher in brome of phenolic origin than in brome of non-phenolic origin (on both thyme- and grass-soil), indicating that life-history variation may be related to environmental factors which also contribute to the spatial differentiation of thyme chemotypes. Moreover, we found that brome growing on thyme-soil in general was heavier than when growing on grass-soil, regardless of the origin of the brome plants. This is concordant with thyme-soil containing higher amounts of organic matter and nitrogen than grass-soil. Our results indicate that patterns of genetic differentiation and local

  16. Environmental Assessment: Armory Addition to CATM with Parking at Grand Forks AFB, North Dakota

    Science.gov (United States)

    2005-07-01

    are tall wheat grass, brome grass, Kentucky bluegrass, sweet clover, and alfalfa. Herbaceous plants include little bluestem, goldenrod, green... wildflower species. Two hundred and fifty five taxa were identified in the ND Natural Heritage Inventory and the BS Bioserve biological inventory update...for Grand Forks Air Force Base. Two rare orchid species are known to exist on Grand Forks AFB, the Large and Small Yellow Lady’s Slipper, identified

  17. Environmental Assessment Housing Transfer at Grand Forks AFB, North Dakota

    Science.gov (United States)

    2005-01-27

    of grasses, legumes, and wild herbaceous plants. Included in the grasses and legumes vegetation species are tall wheat grass, brome grass, Kentucky ...little bluestem, Indian grass, switchgrass, blue gramma, buffalo grass, and many native wildflower species. 35 Two hundred and fifty five taxa...were identified in the ND Natural Heritage Inventory and the BS Bioserve biological inventory update for Grand Forks Air Force Base. Two rare orchid

  18. Environmental Assessment Tent City at Grand Forks AFB, North Dakota

    Science.gov (United States)

    2004-11-15

    legumes, and wild herbaceous plants. Included in the grasses and legumes vegetation species are tall wheat grass, brome grass, Kentucky bluegrass, sweet...bluestem, Indian grass, switchgrass, blue gramma, buffalo grass, and many native wildflower species. Two hundred and fifty five taxa were...identified in the ND Natural Heritage Inventory and the BS Bioserve biological inventory update for Grand Forks Air Force Base. Two rare orchid species are

  19. Finding of No Significant Impact (FONSI) Finding of No Practicable Alternative (FONPA): Construct of a New Fire Station, Demolition of Buildings 530 and 606 and Relocation of the Hazardous Cargo Area at Grand Forks Air Force Base, North Dakota

    Science.gov (United States)

    2009-09-18

    vegetation species are tall wheat grass, brome grass, Kentucky bluegrass, sweet clover and alfalfa. Herbaceous plants include little bluestem, goldenrod...bluestem, little bluestem, Indian grass, switchgrass, blue gramma, buffalo grass and many native wildflower species. The Grand Forks AFB Natural...date, 216 species of birds have been identified as present on base property. Several rare and state-listed species have been observed on base near

  20. American River Watershed Investigation, California. Volume 3. Appendix M

    Science.gov (United States)

    1991-12-01

    fatua X X X Dallis grass Paspalum dilatatum X X Red brome Bromus rubra X X X Bottlebrush squirreltail Sitanion hystrix X X X Notes: OAK -- Associated with...was ignored for two reasons. First, the analyses discounts apparent cohesion at very low stresses. In fact, vegetation ( grass roots) in the upper 6...roots or grass (See Plates 2 and 3 for typical banks). Closer examination of the banks revealed that the materials were often deposited in layers from

  1. Vegetation Evaluation and Recommendations: Dredge Material Placement Areas and Adjacent Lands, Kaskaskia River Navigation Project, New Athens to Fayetteville.

    Science.gov (United States)

    1981-06-03

    288 pp. Mohlenbrock, R. H. 1972. The illustrated flora of Illinois: Grasses : Bromus to Paspalum . Southern Illinois University Press, Carbondale...in less satur- ated areas are Desmodium paniculatum (panicled tick trefoil), Geum canadense (white avens), Paspalum fluitans (swamp bead grass ...tall fescue), Bromus inermis (smooth brome), and Tridens flavus (purple-top) are the most abundant and important grasses in the old fields. Major

  2. Disposal and Reuse of Bergstrom Air Force Base, Texas. Final Environmental Impact Statement.

    Science.gov (United States)

    1993-07-01

    grass (Stipa leucotricha), dallis grass ( Paspalum dilatatum), brome grasses ( Bromus spp.), Johnson grass (Sorghum halepense), and Bermuda grass (Cynodon...cardboard are recycled per day. Metal, textiles, and tires are recycled by the Defense Reutilization and Marketing Office (DRMO). Grass clippings are used... grasses . Most Houston Black soils are suitable for cultivation, native range grasses , hay, or improved pasture. Altoga soils are suited to crops, improved

  3. Environmental Assessment: Construct a CDC Main Entry Addition at Grand Forks Air Force Base

    Science.gov (United States)

    2006-03-01

    Forks County. Pastures, meadows, and other non- cultivated areas create a prairie-land mosaic of grasses, legumes, and wild herbaceous plants...Included in the grasses and legumes vegetation species are tall wheat grass, brome grass, Kentucky bluegrass, sweet clover, and alfalfa . Herbaceous...LAND USE Land use in Grand Forks County consists primarily of cultivated crops with remaining land used for pasture and hay, urban development

  4. Environmental Assessment: Landscape Multiple Areas at Grand Forks Air Force Base

    Science.gov (United States)

    2006-03-01

    and other non- cultivated areas create a prairie-land mosaic of grasses, legumes, and wild herbaceous plants. Included in the grasses and legumes...vegetation species are tall wheat grass, brome grass, Kentucky bluegrass, sweet clover, and alfalfa . Herbaceous plants include little bluestem...Grand Forks County consists primarily of cultivated crops with remaining land used for pasture and hay, urban development, recreation, and wildlife

  5. Environmental Assessment: Construct Airfield Lighting Vault and Demolish Building 531 at Grand Forks Air Force Base

    Science.gov (United States)

    2007-08-01

    Forks County. Pastures, meadows, and other non- cultivated areas create a prairie-land mosaic of grasses, legumes, and wild herbaceous plants. Included...in the grasses and legumes vegetation species are tall wheat grass, brome grass, Kentucky bluegrass, sweet clover, and alfalfa . Herbaceous plants...These are buildings 313, 606, 703, 704, 705, 706, 707, and 714. 3.9 LAND USE Land use in Grand Forks County consists primarily of cultivated crops

  6. Garrison Dam/Lake Sakakawea Master Plan with Integrated Programmatic Environmental Assessment, Missouri River, Montana: Update of Design Memorandum MGR-107D

    Science.gov (United States)

    2007-12-14

    billed gull (Larus delawarensis), California gull (L. californicus), Caspian tern (Sterna caspia), common tern (S. hirundo), least tern (S...introduced annual grasses, biennial and perennial weeds, native forbs, and wildflowers . Common grasses in the WMA’s include smooth brome, tall...forbs, and wildflowers . Crop lands make up a fifth of the vegetation cover. Nearly 10 percent of the land portion of the NWR consists of wetlands

  7. Draft Environmental Impact Report/Environmental Impact Statement, Bel Marin Keys Unit 5. Appendices.

    Science.gov (United States)

    1982-09-01

    covered germinating seeds . Shorebirds rest and feed in these areas in great numbers when high tide covers the Bay mudflats. Once the fields have dried up...Intro- duced species such as wild radish , red brome grass, Italian rye grass, winter vetch, and brass buttons are common, and native pickle- weed...plant, salt grass, sow-thistle, and wild radish . The plants in the undis- turbed marsh area are native species typical of coastal salt marsh. Sow

  8. Potential of Caatinga forage plants in ruminant feeding

    OpenAIRE

    Mércia Virginia Ferreira dos Santos; Mário de Andrade Lira; José Carlos Batista Dubeux Junior; Adriana Guim; Alexandre Carneiro Leão de Mello; Márcio Vieira da Cunha

    2010-01-01

    Caatinga is the most important biome for the livestock in the Brazilian semi-arid region. This review paper aimed to present information on different forage aspects of caatinga vegetation for ruminant feeding. Caatinga vegetation is formed mainly by shrubs and small trees, usually presenting thorns, deciduous leaves, and leaf abscission occurring frequently at the onset of the dry season. Additional components of the botanical composition in this biome includes the families cactaceae, bromeli...

  9. Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

    Science.gov (United States)

    Benizri, R.; Lessart, P.; Courvoisier, P.

    1984-01-01

    A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

  10. Dust and Erosion Control Methods for US Army Construction Projects in Honduras

    Science.gov (United States)

    1989-06-01

    corn, cotton, and Bananas, cafe, cana da azucar. maiz , algadon, y ~-- other crops atraS cosechas Coffee plantations Plantaciones cia cafe shrub...similar competitiveness (tall fescue, smooth brome, or weeping lovegrass). Seed should be inoculated before sowing to receive the nitrogen-fixing...sweetclover is a short-lived perennial legume that tolerates drought, salinity, and alkalinity. It requires inoculation to get maximum benefit from

  11. Potential effects of hydrogen sulfide gas from geothermal energy conversion on two plant species native to northern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, G.J.

    1984-02-01

    Dry weight of topgrowth, water content of topgrowth, leaf nitrogen content, and leaf chlorophyll content were measured in well-watered, field-exposed little bluestem (Schizachyrium scoparium Nash.) and mountain brome (Bromus marginatus Nees.) plants fumigated with various mean levels of H/sub 2/S ranging from 0.05 to 3.58 ppM. The youngest fully expanded leaves were sampled for chlorophyll content after 60, 80, 100, and 140 and 60, 80, 120, and 140 h total of fumigation for little bluestem and mountain brome, respectively. All other responses were measured after 140 h total of fumigation. The plants received a 7-day fumigation-free period prior to the seventh week (140 h) of fumigations. Dry weight of little bluestem plants which received low concentrations of H/sub 2/S (0.11 ppM) increased by 94% of the control. Dry weight of little bluestem plants which received higher concentrations of H/sub 2/S (0.12 to 0.48 ppM) was reduced to the control level. At the highest H/sub 2/S concentration (2.39 ppM) dry weight of little bluestem was reduced by 44% of the control. Mountain brome was relatively unaffected at the different concentrations of H/sub 2/S until 3.58 ppM H/sub 2/S was received where dry weight was reduced by 37% of the control.

  12. Erivajadustega lapsed / Marika Veisson

    Index Scriptorium Estoniae

    Veisson, Marika, 1949-

    2008-01-01

    Vaimupuudega laste arengu ja kasvatuse iseärasustest, ülevaade ka lastest, kellele on pandud Downi sündroomi ja autismi diagnoos ning tserebraalparalüüsi, tähelepanupuudulikkuse ja hüperaktiivsusega lastest

  13. Identification of host fruit volatiles from domestic apple (Malus domestica), native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (C. monogyna) attractive to R. pomonella flies from the western U.S.

    Science.gov (United States)

    The apple maggot fly, Rhagoletis pomonella, infests apple (Malus domestica) and hawthorn species (most notably the downy hawthorn, Crataegus mollis) in the eastern USA. Evidence suggests that the fly was introduced into the western USA sometime in the last 60 years. In addition to apple, R. pomonel...

  14. Silencing of the major family of NBS-LRR-encoding genes in lettuce results in the loss of multiple resistance specificities

    NARCIS (Netherlands)

    Wroblewski, T.; Piskurewicz, U.; Finkers-Tomczak, A.M.; Ochoa, O.; Michelmore, R.

    2007-01-01

    The RGC2 gene cluster in lettuce (Lactuca sativa) is one of the largest known families of genes encoding nucleotide binding site¿leucine-rich repeat (NBS¿LRR) proteins. One of its members, RGC2B, encodes Dm3 which determines resistance to downy mildew caused by the oomycete Bremia lactucae carrying

  15. Three Combined Quantitative Trait Loci from Nonhost Lactuca saligna Are Sufficient to Provide Complete Resistance of Lettuce Against Bremia lactucae

    NARCIS (Netherlands)

    Zhang, N.; Pelgrom, K.T.B.; Niks, R.E.; Visser, R.G.F.; Jeuken, M.J.W.

    2009-01-01

    The nonhost resistance of wild lettuce (Lactuca saligna) to downy mildew (Bremia lactucae) is based on at least 15 quantitative trait loci (QTL), each effective at one or more plant developmental stages. We used QTL pyramiding (stacking) to determine how many of these QTL from L. saligna are suffici

  16. Asclepius or Hippocrates? Differing Interpretations of Post-Compulsory Initial Teacher Training Mentoring

    Science.gov (United States)

    Ingleby, Ewan

    2011-01-01

    This article discusses qualitative research findings on mentoring within PCET ITT (post-compulsory education and training initial teacher training). The article complements the findings of Tedder and Lawy (2009) and Ingleby (2010). The article develops Downie and Randall's consideration of the merits or otherwise of mirroring either "Asclepius" or…

  17. Chapter 4: Nesting Chronology of the Marbled Murrelet

    Science.gov (United States)

    Thomas E. Hamer; S. Kim Nelson

    1995-01-01

    We compiled 86 breeding records of eggs, downy young,and fledgling Marbled Murrelets (Brachyramphus marmoratus) for which the fledging date could be estimated. Records were collected from California (n = 25), Oregon (n = 13), Washington (n = 13), British Columbia (n = 23), and Alaska (n = 12). The number of young fledging increased rapidly from 6...

  18. 77 FR 72873 - Notice of Revocation of Customs Broker Licenses

    Science.gov (United States)

    2012-12-06

    ... Charleston. Sabback Darlene B 10353 Charleston. Lott Jesse J 23539 Charleston. Barr IV Capers 21749... Charlotte. McHale Bernard J 09099 Charlotte. Abernathy Barbara B 15707 Charlotte. McKinnon Candace E 15923.... Flick Barbara L 06943 Chicago. Downie Kevin 05733 Chicago. Santos Pablo C 17201 Chicago. Dai...

  19. Homologous RXLR effectors from Hyaloperonospora arabidopsidis and Phytophthora sojae suppress immunity in distantly related plants

    Science.gov (United States)

    Diverse pathogens secrete effector proteins into plant cells to manipulate host cellular processes. Oomycete pathogens contain very large complements of predicted effector genes defined by an RXLR host cell entry motif. The genome of Hyaloperonospora arabidopsidis (Hpa, downy mildew of Arabidopsis) ...

  20. Behavioral evidence for fruit odor discrimination and sympatric host races of Rhagoletis pomonella flies in the western United States

    Science.gov (United States)

    The recent shift of Rhagoletis pomonella (Diptera: Tephritidae) from its native host downy hawthorn, Crataegus mollis, to introduced domesticated apple, Malus domestica, in the eastern U.S. is a model for sympatric host race formation. However, the fly is also present in the western U.S. where it ma...

  1. REPCO 501452 : Replacement of copper fungicides in organic production of grapevine and apple in Europe : publishable final activity report

    NARCIS (Netherlands)

    Köhl, J.

    2007-01-01

    Final Activity Report: The objective of REPCO was to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on

  2. Contributions of EU-project REPCO to apple scab control

    NARCIS (Netherlands)

    Köhl, J.; Heijne, B.; Hockenhull, J.; Lindhard Pedersen, H.; Trapman, M.; Eiben, U.; Tamm, L.

    2006-01-01

    The objective of REPCO is to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on copper fungicides. Permi

  3. Erivajadustega lapsed / Marika Veisson

    Index Scriptorium Estoniae

    Veisson, Marika, 1949-

    2008-01-01

    Vaimupuudega laste arengu ja kasvatuse iseärasustest, ülevaade ka lastest, kellele on pandud Downi sündroomi ja autismi diagnoos ning tserebraalparalüüsi, tähelepanupuudulikkuse ja hüperaktiivsusega lastest

  4. Characterization of Peronospora belbahrii on basil under light and scanning electron microscopy

    Science.gov (United States)

    Basil (Ocimum spp.) downy mildew caused by Peronsoora belbahrii is a major yield-limiting disease of sweet basil (O. basilicum) production worldwide. In this study, sweet basil was grown in a soilless potting mix in plant growth chambers and inoculated with sporangia of P. belbahrii harvested from p...

  5. Development and application of loop-mediated isothermal amplification (LAMP) for detection of Plasmopara viticola

    NARCIS (Netherlands)

    Kong, X.; Qin, W.; Xiaoqing, X.; Kong, F.; Schoen, C.D.; Feng, J.; Wang, Z.; Zhang, H.

    2016-01-01

    A rapid LAMP (loop-mediated isothermal amplification) detection method was developed on the basis of the ITS sequence of P. viticola, the major causal agent of grape downy mildew. Among the 38 fungal and oomycete species tested, DNA isolated exclusively from P. viticola resulted in a specific

  6. Improving Creative Problem-Solving in a Sample of Third Culture Kids

    Science.gov (United States)

    Lee, Young Ju; Bain, Sherry K.; McCallum, R. Steve

    2007-01-01

    We investigated the effects of divergent thinking training (with explicit instruction) on problem-solving tasks in a sample of Third Culture Kids (Useem and Downie, 1976). We were specifically interested in whether the children's originality and fluency in responding increased following instruction, not only on classroom-based worksheets and the…

  7. 7 CFR 319.24 - Notice of quarantine.

    Science.gov (United States)

    2010-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Corn Diseases Quarantine § 319.24 Notice of..., that maize or Indian corn (Zea mays L.) and closely related plants are subject to certain injurious diseases, especially Peronospora maydis Raciborski, Sclerospora sacchari Miyake and other downy...

  8. The Behaviour of Al Electrodes in Aqueous Solutions,

    Science.gov (United States)

    1981-08-01

    J (19 71): Corrosion 27, 483. (14) Diggle J W, Downie T C, Goulding C W (1969): Chem Rev 69, 365. (15) Dignamn M J, Ryan P J (1968): Can j Chem 46...Binary Alloys, McGraw-Hill Book Corn - pany, New York. (28) Harkness A C, Young L (1966): Can j Chem 44, 641. (29) Hartmann W (1936): Z Physik 102, 709

  9. Installation Restoration Program Records Search for Kingsley Field, Oregon.

    Science.gov (United States)

    1982-06-01

    Festuca ovina x Salt grass 1tchlT i p x June grass Koeleria cristata x Downy chess Bromus tectorum x Wheatgrass AgoXo spp x Sagebrush Artemisia...6.1.1 Type I is intended for use as a corn - accompanied by an official gager’s certifi- paratively safe dry-cleaning solvent. cate showing the net

  10. Civil Engineer Contingency Training Moody Air Force Base, Georgia Environmental Assessment

    Science.gov (United States)

    2007-03-01

    hillsides. Stilson soils occur on low uplands. Most of the cultivated land in Lowndes County is on Tifton and Fuquay soils. Corn , tobacco, soybeans...americanus), ruby-throated hummingbird (Archilochus colubris), woodpeckers ( downy (Picoides pubescens), red-bellied (Melanerpes carolinus), flicker

  11. Aerodynamic and Acoustic Tests of a 1/15 Scale Model Dry Cooled Jet Aircraft Runup Noise Suppression System,

    Science.gov (United States)

    1975-10-01

    has. This required that the model utilize a fiberglass lin!ng (Owens Corning PF-105) having much finer fibers than the full-scale liner, so that the...shut downi in the exhaust room for nearly all runs and soinewhat lai er in the burner room for approximately every second ran. ’or all playback

  12. Nep1-like proteins from three kingdoms of life act as a microbe-associated molecular pattern in Arabidopsis

    NARCIS (Netherlands)

    Raaymakers, Tom M; Oome, Stan; Cabral, Adriana; Samwel, Simon; Böhm, Hannah; Albert, Isabell; Nürnberger, Thorsten; Van den Ackerveken, Guido

    2014-01-01

    Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by a wide range of plant-associated microorganisms. They are best known for their cytotoxicity in dicot plants that leads to the induction of rapid tissue necrosis and plant immune responses. The biotrophic downy milde

  13. Woodpecker Excavation and Use of Cavities in Polystyrene Snags

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz

    1996-01-01

    We examined woodpecker excavation and use of artificial polystyrene snags in four forest types in eastern Texas for five years. Twenty-three of 47 artificial snags were used by Downy Woodpeckers (Picoides pubescens) for cavity excavation and subsequent nocturnal roosting; they did not use the artificial snags for nesting. Although six ather species of woodpeckers...

  14. 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...

  15. Asclepius or Hippocrates? Differing Interpretations of Post-Compulsory Initial Teacher Training Mentoring

    Science.gov (United States)

    Ingleby, Ewan

    2011-01-01

    This article discusses qualitative research findings on mentoring within PCET ITT (post-compulsory education and training initial teacher training). The article complements the findings of Tedder and Lawy (2009) and Ingleby (2010). The article develops Downie and Randall's consideration of the merits or otherwise of mirroring either "Asclepius" or…

  16. Hyaloperonospora camelinae on Camelina sativa (L.) in Washington State: Detection, seed transmission, and chemical control

    Science.gov (United States)

    Camelina (Camelina sativa [L.] Crantz) plants with symptoms of downy mildew were obtained from three different locations in Washington State. Based on PCR and sequencing of the ITS1-5.8S-ITS2 region, the causal pathogen was identified as Hyaloperonospora camelinae. The PCR primers consistently ampli...

  17. Detection, seed transmission, and control of Hyaloperonospora camelinae on Camelina sativa (L.) in Washington State

    Science.gov (United States)

    Camelina (Camelina sativa [L.] Crantz) plants with symptoms of downy mildew were obtained from three different locations in Washington State. Based on PCR and sequencing of the ITS1-5.8S-ITS2 region, the causal pathogen was identified as Hyaloperonospora camelinae. The PCR primers consistently ampli...

  18. Cultural Resources Inventory of Lands Adjacent to Big Sandy Lake. Volume 1,

    Science.gov (United States)

    1979-01-18

    Bush honeysuckle JuneberryI Downy arrowwood q erbs: Wild sarsaparilla Pennsylvania sedge Columbine Early meadow-rue Large-leaved aster Star-flowered...valley Canada anemone Snakeroot Wild sarsaparilla " Northern bedstraw Br.-leaved goldenrod False Solomon’s seal Carrion flower Small-flowered Large

  19. Oospora populations of Peronospora viciae: quantification, germinability andsurvival.

    NARCIS (Netherlands)

    Gaag, van der D.J.

    1997-01-01

    Peronospora viciae causes downy mildew on pea, field and broad bean. Two pathogens can be distinguished, P. viciae f.sp. pisi on pea (Pisum sativum) and P. viciae f. sp. fabae on field and broad bean (Vicia faba). These pathogens form resting spores, called oospores, in their host plant tissue. The

  20. Unraveling landscapes with phytogenic mounds (nebkhas): An exploration of spatial pattern

    Science.gov (United States)

    Quets, Jan J.; Temmerman, Stijn; El-Bana, Magdy I.; Al-Rowaily, Saud L.; Assaeed, Abdulaziz M.; Nijs, Ivan

    2013-05-01

    Phytogenic mounds (nebkhas) often are symptoms of desertification in arid regions. Interactions among nebkhas and between nebkhas and their environment are however poorly examined. To this end, three main hypotheses of nebkha pattern formation were evaluated in this study. These state that nebkha patterns are either shaped by: (i) biologically induced recruitment inhibiting zones, (ii) biologically induced recruitment encouraging zones, or (iii) by the spatial distribution of abiotic factors which are not biologically driven. Contrasting nebkha landscapes were examined: a highly dense New Mexican mesquite (Prosopis glandulosa) and snakeweed (Gutierrezia sarothrae and Gutierrezia microcephala) ecosystem, and a low-density mixed Tamarix aphylla and Calligonum comosum field in central Libya. Spatial second-order statistics of strategically chosen nebkha subpatterns were compared with those of null models in which observed patches were spatially randomized without overlap. Null model deviations were assessed with goodness-of-fit tests, and interpreted in terms of hypothesized mechanisms of nebkha pattern formation. Our results suggest that biologically induced recruitment inhibiting zones surround adult mesquite nebkhas. The configuration of Calligonum and Tamarix nebkhas may be driven by spatial dynamics of abiotic microsites which are not caused by nebkha interactions. Hence we conclude that both biotic and abiotic drivers can shape nebkha spatial patterns.

  1. Comparison of lettuce diseases and yield under subsurface drip and furrow irrigation.

    Science.gov (United States)

    Subbarao, K V; Hubbard, J C; Schulbach, K F

    1997-08-01

    ABSTRACT Subsurface drip and furrow irrigation were compared on lettuce (Lactuca sativa) cvs. Salinas and Misty Day for yield and incidence and severity of three important diseases of lettuce in the Salinas Valley, CA. Experiments were conducted between 1993 and 1995 during the spring and fall seasons. The diseases examined included lettuce drop (Sclerotinia minor), downy mildew (Bremia lactucae), and corky root (Rhizomonas suberifaciens). Replicated plots of subsurface drip and furrow irrigation were arranged in a randomized complete-block design. All plants were inoculated with S. minor at the initiation of the experiment during the 1993 spring season. Plots were not inoculated for downy mildew and corky root during any season nor were the plots reinoculated with S. minor. During each season, all plots were sprinkler irrigated until thinning, and subsequently, the irrigation treatments were begun. The furrow plots were irrigated once per week, and the drip plots received water twice per week. The distribution of soil moisture at two soil depths (0 to 5 and 6 to 15 cm) at 5, 10, and 15 cm distance on either side of the bed center in two diagonal directions was significantly lower in drip-irrigated compared with furrow-irrigated plots. Plots were evaluated for lettuce drop incidence and downy mildew incidence and severity at weekly intervals until harvest. Corky root severity and yield components were determined at maturity. Lettuce drop incidence and corky root severity were significantly lower and yields were higher in plots under subsurface drip irrigation compared with furrow irrigation, regardless of the cultivar, except during the 1994 fall season. Incidence and severity of downy mildew were not significantly different between the two irrigation methods throughout the study. The differential microclimates created by the two irrigation treatments did not affect downy mildew infection, presumably because the mesoclimate is usually favorable in the Salinas

  2. Morphological and molecular analyses support the existence of host-specific Peronospora species infecting Chenopodium.

    Science.gov (United States)

    Choi, Young-Joon; Denchev, Cvetomir M; Shin, Hyeon-Dong

    2008-03-01

    About 20 species of Peronospora have been reported to cause downy mildew on Chenopodium, but, particularly in plant pathology literature, only one species, P. farinosa, is considered to be involved. We performed sequence analysis of the ITS rDNA to reveal the phylogenetic relationships of Peronospora specimens from five species of Chenopodium, viz. C. album, C. ambrosioides, C. bonus-henricus, C. hybridum, and C. polyspermum. The five clades corresponded to particular Chenopodium species, and showed a high level of sequence divergence. Differences in the morphology of the conidia and ultimate branchlets also supported the separation of the five groups at the host species level. These results suggest that the names P. variabilis, P. boni-henrici, P. chenopodii, and P. chenopodii-polyspermi should be used for the four downy mildew pathogens specific to C. album, C. bonus-henricus, C. hybridum, and C. polyspermum, respectively. The Peronospora on C. ambrosioides was found to be an independent species.

  3. Algunos aspectos de anatomía foliar comparada de dos especles de Bromeliaceae (Aechmea mexicana Baker y Hechtia glomerata Zucc.)

    OpenAIRE

    Flores, Eugenia M.

    2016-01-01

    La anatomía foliar de las bromeliáceas mereció la atención de muchos investigadores como ANDRE (1), BEER (3), CHEVALIER (8), DUVAL (9), KOCK (13), MEZ (16), ROBINSON (22), SOLEREDER y MEYER (28) Y TOMLINSON (30). La mayoría de estos estudios describen las estructuras, sin establecer relación con la ecología de las plantas. Entre los trabajos anatómico·ecológicos realizados cabe destacar el de SCHIMPER (26), quien relacionó la economía del agua con el epifitismo, y la tesis de PICADO (19) sobr...

  4. Plant virus-resembling optical nano-materials conjugated with anti-EGFR for targeted cancer imaging

    Science.gov (United States)

    Gupta, Sharad; Wilder, Hailey; Rao, A. L. N.; Vullev, V. I.; Anvari, Bahman

    2012-03-01

    We recently reported the construction of a new type of optically active nano-particles composed of genome-depleted plant infecting brome mosaic virus (BMV) doped with indocyanine green (ICG), an FDA-approved chromophore . We refer to these constructs as optical viral ghosts (OVGs) since only the capsid protein (CP) subunits of BMV remain to encapsulate ICG. Herein, we covalently conjugated the surface of OVGs with anti-epidermal growth factor receptors (anti-EGFR) to target cancerous human bronchial epithelial cells (C-HBECs) in-vitro. Our preliminary results demonstrate the utility of conjugated OVGs for targeted imaging of cancer cells.

  5. Atlantis FLEX (BAY 22010 H – a new herbicide in cereals with efficacy against grasses

    Directory of Open Access Journals (Sweden)

    Kerlen, Dirk

    2014-02-01

    Full Text Available Atlantis FLEX (Mesosulfuron-methyl; Propoxycarbazone-sodium; Mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides, ryegrass (Lolium spec., brome grass (Bromus spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L, annual meadow-grass (Poa annua L. and dicot weeds. Atlantis FLEX can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis FLEX. It will be shown, that Atlantis FLEX generates a good to excellent efficacy against grass-weeds.

  6. Comparative assessment of the phytomeliorative efficiency of perennial grasses on chernozems in the transural part of Bashkortostan

    Science.gov (United States)

    Khasanova, R. F.; Suyundukov, Ya. T.; Suyundukova, M. B.

    2010-01-01

    The phytomeliorative efficiency of different groups of perennial herbs was studied. The agrophysical properties of soils under natural grasses (the feather grasses Stipa pennata, S. zalesskii, and S. Lessingiana; the fescue grass Festuca pseudovina; and quack grass), sawn herbs (awnless brome, crested wheat grass, purple alfalfa, the holy clover Onobrychis sibirica, the galega Galega orientalis, and yellow sweet clover), and cereal crops (winter rye and spring wheat) were compared. The formation of the aboveground and underground phytomass and the influence of phytomeliorative herbs on the aggregate state of leached, ordinary, and southern chernozems in the Transural part of Bashkortostan were analyzed.

  7. Contact Mechanics of a Small Icosahedral Virus

    Science.gov (United States)

    Zeng, Cheng; Hernando-Pérez, Mercedes; Dragnea, Bogdan; Ma, Xiang; van der Schoot, Paul; Zandi, Roya

    2017-07-01

    A virus binding to a surface causes stress of the virus cage near the contact area. Here, we investigate the potential role of substrate-induced structural perturbation in the mechanical response of virus particles to adsorption. This is particularly relevant to the broad category of viruses stabilized by weak noncovalent interactions. We utilize atomic force microscopy to measure height distributions of the brome mosaic virus upon adsorption from solution on atomically flat substrates and present a continuum model that captures our observations and provides estimates of elastic properties and of the interfacial energy of the virus, without recourse to indentation.

  8. Atlantis Star – a new herbicide in cereals with efficacy against grasses and dicots

    Directory of Open Access Journals (Sweden)

    Kerlen, Dirk

    2016-02-01

    Full Text Available Atlantis Star (mesosulfuron-methyl; iodosulfuron-methyl-sodium; thiencarbazone-methyl; mefenpyr-diethyl is a new cereal herbicide to control blackgrass (Alopecurus myosuroides; sensitive and high infestation, brome grass (Bromus spec., ryegrass (Lolium spec., wild oat (Avena fatua, loose silky-bentgrass (Apera spica-venti L., annual meadow-grass (Poa annua L. and dicot weeds. Atlantis Star can be used in winter wheat, winter triticale, winter rye, winter durum wheat and spelt. The publication is based on efficacy trials from two years of spring application with Atlantis Star.

  9. Potential use of RAPD markers in characteristics of cucumber (Cucumis sativus L. haploids and double-haploids

    Directory of Open Access Journals (Sweden)

    Katarzyna Niemirowicz-Szczytt

    2011-04-01

    Full Text Available A study was designed to obtain hapolid and double haploid (DH plants from cucumber cultivars tolerant to Pseudoperonospora cubensis. The main goal was to identify RAPD molecular markers associated with downy mildew resistance. On average, 20% of embryos generated in two experiments, were converted to haploid plants. RAPD markers that differentiated susceptible and resistant H and DH plants were identified. Somaclonal variation in DH lines was seldom detected.

  10. Effects of Some Plant Essential Oils Against Botrytis cinerea and Tetranychus urticae on Grapevine

    OpenAIRE

    DOĞU, Duygu MERMER; ZOBAR, Damla

    2014-01-01

    The cultivation of grapes in the world in terms of the first-ranked Turkey as well as the appropriate climatic zone, has potential for rich gene and ancient viticulture culture. Grape growers, starting from production until it reaches the consumer is faced with various problems in the process. Plant protection faced in the vineyards of the manufacturers in terms of the most important causes of losses; Downy Mildew (Plasmopara viticola), Powdery Mildew (Uncinula necator), Gray mold (Botrytis c...

  11. A De Novo-Assembly Based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies

    OpenAIRE

    Li Guo; Kelly S Allen; Greg A Deiulio; Yong Zhang; Madeiras, Angela M.; Robert L Wick; Li-Jun Ma

    2016-01-01

    Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression anal...

  12. Fungicidal preparations from Inula viscose

    OpenAIRE

    2002-01-01

    Inula viscosa is a perennial plant native to the Mediterranean Basin. Extracts made from the shoots of this plant exhibited a strong fungicidal activity in vitro and in vivo. TLC analyses revealed at least 7 fungicidal compounds. Most are lipophilic. When such extracts were sprayed on the leaf surface of crop plants they effectively controlled downy mildew in grape, cucumber and tabacco; late blight in potato and tomato; gray mold in cucumber and tomato; and, powdery mildew in cucurbits and c...

  13. Potentiel évolutif et adaptation des populations de l'agent du mildiou de la laitue, Bremia lactucae, face aux pressions de sélection de la plante hôte, Lactuca sativa

    OpenAIRE

    Valade, Romain

    2012-01-01

    Resistance genes introgressed into cultivated plants are frequently overcame by pathogens, causing outbreaks and economic losses. Therefore, understanding the evolutionary strategies involved in the adaptation of pathogen populations is needed to improve the sustainable management of resistance. Bremia lactucae, the lettuce downy mildew, is under strong selection pressure exerted by host resistance genes. Under this selection pressure, B. lactucae populations showed a rapid adaptation to host...

  14. REPCO 501452 : Replacement of copper fungicides in organic production of grapevine and apple in Europe : publishable final activity report

    OpenAIRE

    Köhl, J

    2007-01-01

    Final Activity Report: The objective of REPCO was to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on copper fungicides. Permitted amounts will be reduced stepwise in the years ahead (Council Regulation (EEC) 2092/91, Annex II) to avoid environmental risks. In European countries where copper fungic...

  15. Effects of Whole and Partial Body Exposure to Dry Heat on Certain Performance Measures.

    Science.gov (United States)

    1981-05-01

    of the study and interpretation of data: Dr. Arthur L Dudycha, Dr. Barry H. Kantowitz , Dr. N. M. Downie, Dr. Ernest J. McCormick, and Dr. Robert D...The interpretation of reaction time in information-processing research. In Kantowitz , B. H. (Ed.), Human information processing: Tutorials in...performance. In Kantowitz , B. H. (Ed.), Human Information Processing: Tutorials in performance and cognition. Hillsdale, New Jersey: Lawrence Erlbaum Associates

  16. Proceedings, Workshop on Prediction of Groundwater Flow into Deep Tunnels and Excavations, 18-19 February 1987

    Science.gov (United States)

    1993-08-01

    yield tighter fractures with correspondingly lower flow rates than more brittle rocks such as granite. He also suggested that seismic activity can...between 500 and 700 meters were all very similar. Mr. Gates indicated that the transmissivities at the Hanford nuclear waste repository site also... Hanford , 15 test sections were installed in a single 4,000-ft drill hole. The equipment was also used at Downie Slide and Dutchman’s Ridge Slide on the

  17. Environmental Assessment: Construction Projects at the 189th Airlift Wing, Arkansas Air National Guard

    Science.gov (United States)

    2003-09-12

    bellied Woodpecker (Melanerpes carolinus), Downy Woodpecker (Picoides pudescens), Blue Jay (Cyanocitta cristata), Carolina Chickadee (Parus...were the Eastern Towhee (Pipilo erythrophthalmus), Carolina Wren, and Blue Jay. Twenty-four species were recorded in grassland habitats on Little...WILCOX GROUP MIDWAY GROUP ANNONA CHALK OZAN FORli.ATION BROWNSTOWN KARL TOKIO FORMATION WOODBINE FORMA’rlON KIAMICHI F’ORMATJON AND GOODLAND

  18. Gene Environment Interactions in Women With Breast and Secondary Lung Cancer

    Science.gov (United States)

    2006-07-01

    Komorowski,J., Bell,A.K., Downie ,I., Mooney,J., Verbeke,C., Bellamy,C., and Keith,W.N. (2005) Markers of adenocarcinoma characteristic of the site of...sensitivity. Am.J.Clin.Pathol., 123, 9-12. 107. Esteller,M., Corn ,P.G., Baylin,S.B., and Herman,J.G. (2001) A gene hypermethylation profile of human

  19. USSR Report, Agriculture.

    Science.gov (United States)

    2007-11-02

    for corn , peas, and sunflowers, in the dosages recommended for each crop. In areas of occurrence of downy mildew of sunflowers, seed is treated...Seed in Kirghiz SSR (SEL’ SKOYE KHOZYAYSTVO KIRGIZII, No 9, Sep 83) 24 Briefs Seed for Spring Sowing 29 Expansion of Sorghum Crop 29 Corn Crop...Figures covering many years, from research conducted by the All-Union Corn Scientific Research Institute and other scientific establishments

  20. Hubungan Antara Keragaman Gulma dengan Penyakit Bulai pada Jagung (Zea mays L.) Stadium Pertumbuhan Vegetatif

    OpenAIRE

    I MADE SUDARMA; I KETUT SUADA; KETUT AYU YULIADHI

    2013-01-01

    Weeds play an important role in the spread of downy mildew disease, competition, and lower cropyields of corn. Research using the survey method in 3 locations of Sanur village, Denpasar City. Eachlocation is taken 5 samples, and each sample area was 1m2, which was arranged diagonally. Forweeds identification was using reference i.e. Weeds of rice in Indonesia, and identification of downymildew disease using reference i.e. Maize Disease: A Guide for Field Indentification and microscopically,wh...

  1. Sunflower crop in Argentina to date

    OpenAIRE

    Vasquez A.; de Romano A.

    2006-01-01

    Inside a panorama of a spectacular grain production in the last 10 years in Argentina, sunflower crop participates with an annual production of more than 3,500,000 t. During that period, many advances were made in the improvement of diseases resistance: Verticillium wilt, downy mildew and head rot. Also oil yield per hectare continued to increase. The new hybrids have new qualities, for example imidazolinones resistance, which allows farmers to keep yields, although the soils destined to sunf...

  2. The Ethical Imperative of Reason: How Anti-Intellectualism, Denialism, and Apathy Threaten National Security

    Science.gov (United States)

    2016-03-01

    NUMBER OF PAGES 89 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified...Sagan, Billions and Billions (New York: Random House , 1999). 78 Martin Weigel, “Beware the Altar of Science: We Are More than Data and Chemicals...important-climate-change- skeptics-2009-7?op=1; Clive Hamilton and Christian Downie, Scorcher: The Dirty Politics of Climate Change ( Melbourne , Australia

  3. Development of a Brief Self-Report Measure of Work-Related Cognitive Limitations in Breast Cancer Survivors

    Science.gov (United States)

    2013-01-08

    2012; Downie, Mar Fan, Houede-Tchen, Yi, & Tannock, 2006; Janelsins et al., 2011; Shilling, Jenkins, Morris, Deutsch, & Bloomfield , 2005). For some... Bloomfield , D., Morris, R., Allan, S., et al. (2006). A 3- year prospective study of the effects of adjuvant treatments on cognition in women with...Morris, R., Deutsch, G., & Bloomfield , D. (2005). The effects of adjuvant chemotherapy on cognition in women with breast cancer--preliminary

  4. Acquired hypertrichosis lanuginosa

    Directory of Open Access Journals (Sweden)

    Kumar Pramod

    1993-01-01

    Full Text Available Acquired hypertirichosis lanuginose developed rapidly in a patient with no detectable malignancy. Soft, fine, downy hair growth was noticed on the face, ears, limbs and trunk. Bilaterally symmetrical vitiliginous macules were present on the ear and preauricular region. This case is reported because of its rarity, absence of any detectable malignancy and development of vitiligo, which to our knowledge has not been reported earlier.

  5. Reconnaissance Waccamaw River Basin North Carolina and South Carolina. Flood Control and Related Purposes.

    Science.gov (United States)

    1981-09-01

    leaf tobacco is by far the most important crop grown and is the economic mainstay of the basin. Farming is found almost entirely in tributary areas...nities for wi.i ire are such species as blackberry (Rubus argutus), Japanese honeyscckle (Lonicera japonica), sa2.;afras (Sassafras albidum), black...the understory layer. Birds such as the wood thrush, hooded warbler , and downy wood- pecker inhabit this layer. Gray squirrels, opossums, and suuthern

  6. Secondary plant succession on disturbed sites at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Angerer, J.P.; Ostler, W.K.; Gabbert, W.D.; Schultz, B.W.

    1994-12-01

    This report presents the results of a study of secondary plant succession on disturbed sites created during initial site investigations in the late 1970s and early 1980s at Yucca Mountain, NV. Specific study objectives were to determine the rate and success of secondary plant succession, identify plant species found in disturbances that may be suitable for site-specific reclamation, and to identify environmental variables that influence succession on disturbed sites. During 1991 and 1992, fifty seven disturbed sites were located. Vegetation parameters, disturbance characteristics and environmental variables were measured at each site. Disturbed site vegetation parameters were compared to that of undisturbed sites to determine the status of disturbed site plant succession. Vegetation on disturbed sites, after an average of ten years, was different from undisturbed areas. Ambrosia dumosa, Chrysothamnus teretifolius, Hymenoclea salsola, Gutierrezia sarothrae, Atriplex confertifolia, Atriplex canescens, and Stephanomeria pauciflora were the most dominant species across all disturbed sites. With the exception of A. dumosa, these species were generally minor components of the undisturbed vegetation. Elevation, soil compaction, soil potassium, and amounts of sand and gravel in the soil were found to be significant environmental variables influencing the species composition and abundance of perennial plants on disturbed sites. The recovery rate for disturbed site secondary succession was estimated. Using a linear function (which would represent optimal conditions), the recovery rate for perennial plant cover, regardless of which species comprised the cover, was estimated to be 20 years. However, when a logarithmic function (which would represent probable conditions) was used, the recovery rate was estimated to be 845 years. Recommendations for future studies and site-specific reclamation of disturbances are presented.

  7. IN VITRO ANTIINFLAMMATORY ACTIVITY OF FICUS BENGHALENSIS BARK

    Directory of Open Access Journals (Sweden)

    Matpal Mahesh

    2013-07-01

    Full Text Available To evaluate the anti-inflammatory property of the different extract of bark of Ficus benghalensis, family Moraceae is a very large, fast growing, evergreen tree up to 30 meters, with spreading branches and many aerial roots. Leaves stalked, ovate-cordate, 3-nerved, entire, when young downy on both sides; petiole with a broad smooth greasy gland at the apex, compressed, downy; Fruit in axillary pairs, the size of a cherry, round and downy. According to Ayurveda, it is astringent to bowels; useful in treatment of biliousness, ulcers, erysipelas, vomiting, vaginal complains, fever, inflammations, leprosy. According to Unani system of medicine, its latex is aphrodisiac, tonic, vulernary, maturant, lessens inflammations; useful in piles etc. The present study aimed at the evaluation of anti-inflammatory property of the aqueous, chloroform and alcoholic extracts of the bark by in vitro methods. In vitro method was estimated by human red blood cell membrane stabilization (HRBC method. Results showed significant anti-inflammatory property of the different extracts tested. The methanolic extract at a concentration of 200 mg/ml. showed potent activity on comparing with the standard drug diclofenac sodium.

  8. Leaf Treatments with a Protein-Based Resistance Inducer Partially Modify Phyllosphere Microbial Communities of Grapevine

    Science.gov (United States)

    Cappelletti, Martina; Perazzolli, Michele; Antonielli, Livio; Nesler, Andrea; Torboli, Esmeralda; Bianchedi, Pier L.; Pindo, Massimo; Puopolo, Gerardo; Pertot, Ilaria

    2016-01-01

    Protein derivatives and carbohydrates can stimulate plant growth, increase stress tolerance, and activate plant defense mechanisms. However, these molecules can also act as a nutritional substrate for microbial communities living on the plant phyllosphere and possibly affect their biocontrol activity against pathogens. We investigated the mechanisms of action of a protein derivative (nutrient broth, NB) against grapevine downy mildew, specifically focusing on the effects of foliar treatments on plant defense stimulation and on the composition and biocontrol features of the phyllosphere microbial populations. NB reduced downy mildew symptoms and induced the expression of defense-related genes in greenhouse- and in vitro-grown plants, indicating the activation of grapevine resistance mechanisms. Furthermore, NB increased the number of culturable phyllosphere bacteria and altered the composition of bacterial and fungal populations on leaves of greenhouse-grown plants. Although, NB-induced changes on microbial populations were affected by the structure of indigenous communities originally residing on grapevine leaves, degrees of disease reduction and defense gene modulation were consistent among the experiments. Thus, modifications in the structure of phyllosphere populations caused by NB application could partially contribute to downy mildew control by competition for space or other biocontrol strategies. Particularly, changes in the abundance of phyllosphere microorganisms may provide a contribution to resistance induction, partially affecting the hormone-mediated signaling pathways involved. Modifying phyllosphere populations by increasing natural biocontrol agents with the application of selected nutritional factors can open new opportunities in terms of sustainable plant protection strategies. PMID:27486468

  9. Hubungan Antara Keragaman Gulma dengan Penyakit Bulai pada Jagung (Zea mays L. Stadium Pertumbuhan Vegetatif

    Directory of Open Access Journals (Sweden)

    I MADE SUDARMA

    2013-08-01

    Full Text Available Weeds play an important role in the spread of downy mildew disease, competition, and lower cropyields of corn. Research using the survey method in 3 locations of Sanur village, Denpasar City. Eachlocation is taken 5 samples, and each sample area was 1m2, which was arranged diagonally. Forweeds identification was using reference i.e. Weeds of rice in Indonesia, and identification of downymildew disease using reference i.e. Maize Disease: A Guide for Field Indentification and microscopically,while the weeds diversity was determined based on Diversity Index of Shannon-Wiener. Relationshipbetween number of weed species and weed populations, and disease incidence were determined byregression and correlation analysis. Weed diversity on ecosystem of maize in vegetative stage is verylow with the diversity index of 0.779, this means weed ecosystem unstable, and dominated by a particularweed species was Paspalum commersonii Lamk. (Fam. Poaceae/Graminaceae of 23.3%, with thedominance index of 0.709. Relationship between the number of weed species and disease incidence ofthe downy mildew disease was highly significant (P<0,01, while the relationship between weed populationand disease incidence of the downy mildew disease is not significant. Plant height and leaf number ofmaize was influenced by the type of weed, but weed populations only affect plant height of maize invegetative stage (V3-V11.

  10. Leaf Treatments with a Protein-Based Resistance Inducer Partially Modify Phyllosphere Microbial Communities of Grapevine.

    Science.gov (United States)

    Cappelletti, Martina; Perazzolli, Michele; Antonielli, Livio; Nesler, Andrea; Torboli, Esmeralda; Bianchedi, Pier L; Pindo, Massimo; Puopolo, Gerardo; Pertot, Ilaria

    2016-01-01

    Protein derivatives and carbohydrates can stimulate plant growth, increase stress tolerance, and activate plant defense mechanisms. However, these molecules can also act as a nutritional substrate for microbial communities living on the plant phyllosphere and possibly affect their biocontrol activity against pathogens. We investigated the mechanisms of action of a protein derivative (nutrient broth, NB) against grapevine downy mildew, specifically focusing on the effects of foliar treatments on plant defense stimulation and on the composition and biocontrol features of the phyllosphere microbial populations. NB reduced downy mildew symptoms and induced the expression of defense-related genes in greenhouse- and in vitro-grown plants, indicating the activation of grapevine resistance mechanisms. Furthermore, NB increased the number of culturable phyllosphere bacteria and altered the composition of bacterial and fungal populations on leaves of greenhouse-grown plants. Although, NB-induced changes on microbial populations were affected by the structure of indigenous communities originally residing on grapevine leaves, degrees of disease reduction and defense gene modulation were consistent among the experiments. Thus, modifications in the structure of phyllosphere populations caused by NB application could partially contribute to downy mildew control by competition for space or other biocontrol strategies. Particularly, changes in the abundance of phyllosphere microorganisms may provide a contribution to resistance induction, partially affecting the hormone-mediated signaling pathways involved. Modifying phyllosphere populations by increasing natural biocontrol agents with the application of selected nutritional factors can open new opportunities in terms of sustainable plant protection strategies.

  11. Leaf treatments with a protein-based resistance inducer partially modify phyllosphere microbial communities of grapevine

    Directory of Open Access Journals (Sweden)

    Martina Cappelletti

    2016-07-01

    Full Text Available Protein derivatives and carbohydrates can stimulate plant growth, increase stress tolerance and activate plant defense mechanisms. However, these molecules can also act as a nutritional substrate for microbial communities living on the plant phyllosphere and possibly affect their biocontrol activity against pathogens. We investigated the mechanisms of action of a protein derivative (nutrient broth, NB against grapevine downy mildew, specifically focusing on the effects of foliar treatments on plant defense stimulation and on the composition and biocontrol features of the phyllosphere microbial populations. NB reduced downy mildew symptoms and induced the expression of defense-related genes in greenhouse- and in vitro-grown plants, indicating the activation of grapevine resistance mechanisms. Furthermore, NB increased the number of culturable phyllosphere bacteria and altered the composition of bacterial and fungal populations on leaves of greenhouse-grown plants. Although NB-induced changes on microbial populations were affected by the structure of indigenous communities originally residing on grapevine leaves, degrees of disease reduction and defense gene modulation were consistent among the experiments. Thus, modifications in the structure of phyllosphere populations caused by NB application could partially contribute to downy mildew control by competition for space or other biocontrol strategies. Particularly, changes in the abundance of phyllosphere microorganisms may provide a contribution to resistance induction, partially affecting the hormone-mediated signaling pathways involved. Modifying phyllosphere populations by increasing natural biocontrol agents with the application of selected nutritional factors can open new opportunities in terms of sustainable plant protection strategies.

  12. Electron microscopy and composition of raw acorn starch in relation to in vivo starch digestibility.

    Science.gov (United States)

    Cappai, Maria Grazia; Alesso, Giuseppe Andrea; Nieddu, Giuseppa; Sanna, Marina; Pinna, Walter

    2013-06-01

    The structure and composition of starch play an important role as co-factors affecting raw starch digestibility: such features were investigated in raw acorn starch from the most diffused oak trees in the Mediterranean basin. A total of 620 whole ripe acorns from Holm (Quercus ilex L., n = 198), Downy (Quercus pubescens Willd., n = 207) and Cork (Quercus suber L., n = 215) oaks sampled on the Sardinia Isle (40° 56' 0'' N; 9° 4' 0'' E; 545 m above the mean sea level) in the same geographical area, were analyzed for their chemical composition. The starch contents ranged between 51.2% and 53.5% of dry matter. The starch granules displayed a spheroid/ovoid and cylindrical shape; on scanning electron microscopic (SEM) analyses, a bimodal distribution of starch granule size was observed both for Holm and Cork oak acorns, whereas the starch granules of Downy oak acorns showed diameters between 10.2 and 13.8 μm. The specific amylose to amylopectin ratio of acorn starch was 25.8%, 19.5% and 34.0% in the Holm, Downy and Cork oaks, respectively. The (13)C Nuclear Magnetic Resonance (NMR) signal analysis displayed a pivotal spectrum for the identification of the amylose peaks in raw acorn starch, as a basis for the amylose to amylopectin ratio determination.

  13. Universally Primed-PCR indicates geographical variation of Peronospora farinosa ex. Chenopodium quinoa.

    Science.gov (United States)

    Danielsen, Solveig; Lübeck, Mette

    2010-02-01

    In the Andean region of South America downy mildew, caused by Peronospora farinosa, is the most important disease of quinoa (Chenopodium quinoa). Peronospora farinosa, a highly polyphyletic species, occurs on quinoa and wild relatives on all continents. However, very little is known about the geographic diversity of the pathogen. As the interest in quinoa as a novel crop is increasing worldwide, geographical differences in the population structure of the downy mildew pathogen must be taken into consideration in order to design appropriate control strategies under a variety of circumstances. As a step towards understanding the geographic diversity of P. farinosa from quinoa, 40 downy mildew isolates from the Andean highlands and Denmark were characterized using universally primed PCR (UP-PCR). Eight UP-PCR primers were tested. A combined analysis of markers separated the Danish and Andean isolates in two distinct clusters. This study raises new questions about the origin and spread of P. farinosa on quinoa, its geographic diversity and host specificity.

  14. Characterization of successional changes in bacterial community composition during bioremediation of used motor oil-contaminated soil in a boreal climate.

    Science.gov (United States)

    Yan, Lijuan; Sinkko, Hanna; Penttinen, Petri; Lindström, Kristina

    2016-01-15

    The widespread use of motor oil makes it a notable risk factor to cause scattered contamination in soil. The monitoring of microbial community dynamics can serve as a comprehensive tool to assess the ecological impact of contaminants and their disappearance in the ecosystem. Hence, a field study was conducted to monitor the ecological impact of used motor oil under different perennial cropping systems (fodder galega, brome grass, galega-brome grass mixture and bare fallow) in a boreal climate zone. Length heterogeneity PCR characterized a successional pattern in bacterial community following oil contamination over a four-year bioremediation period. Soil pH and electrical conductivity were associated with the shifts in bacterial community composition. Crops had no detectable effect on bacterial community composition or complexity. However, the legume fodder galega increased soil microbial biomass, expressed as soil total DNA. Oil contamination induced an abrupt change in bacterial community composition at the early stage, yet the effect did not last as long as the oil in soil. The successional variation in bacterial community composition can serve as a sensitive ecological indicator of oil contamination and remediation in situ.

  15. Sperm morphological and morphometric evaluation in captive collared peccaries (Pecari tajacu

    Directory of Open Access Journals (Sweden)

    Patrícia C. Sousa

    2013-07-01

    Full Text Available The aim of this study was to compare different staining methods for the evaluation of sperm morphology by light microscopy and also to describe the morphometry of the entire sperm in collared peccaries (Pecari tajacu. Semen from 10 males was obtained by electroejaculation and evaluated for sperm motility, vigor, and concentration. Semen smears were prepared through three different staining methods: Bengal rose, brome-phenol blue, and eosin-nigrosin. Smears were evaluated under light microscopy and sperm morphologic alterations were determined in percentage. In addition, sperm morphometric analysis was conducted by light microscopy coupled to image analyzer software. The smears stained with Bengal Rose provide the best results for the visualization of the sperm tail, midpiece, and head. The use of eosin-nigrosin stain did not allow an adequate impregnation, and some sperm presented a few contrasts with the background. A higher incidence of bent coiled tails was verified in the use of brome-phenol blue staining (P<0.05. Through morphometric evaluation, it was observed that the tail occupies the greatest proportion (89% of the sperm which presents a discretely elongated head. According to the results, the use of the Bengal Rose stain is recommended for the morphologic evaluation of the collared peccary sperm.

  16. Utilizing virus-induced gene silencing for the functional characterization of maize genes during infection with the fungal pathogen Ustilago maydis.

    Science.gov (United States)

    van der Linde, Karina; Doehlemann, Gunther

    2013-01-01

    While in dicotyledonous plants virus-induced gene silencing (VIGS) is well established to study plant-pathogen interaction, in monocots only few examples of efficient VIGS have been reported so far. One of the available systems is based on the brome mosaic virus (BMV) which allows gene silencing in different cereals including barley (Hordeum vulgare), wheat (Triticum aestivum), and maize (Zea mays).Infection of maize plants by the corn smut fungus Ustilago maydis leads to the formation of large tumors on stem, leaves, and inflorescences. During this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed comprehensive and stage-specific changes in host gene expression during disease progression.To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a VIGS system based on the Brome mosaic virus (BMV) to maize at conditions that allow successful U. maydis infection of BMV pre-infected maize plants. This setup enables quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (q(RT)-PCR)-based readout.

  17. Seed ecology of Bromus sterilis L.

    Directory of Open Access Journals (Sweden)

    Žďárková, Veronika

    2014-02-01

    Full Text Available Bromus sterilis L. (barren brome has become a troublesome weed of winter cereals in reduced tillage systems, mainly in South and North America, middle and Western Europe. In the Czech Republic, its importance has increased dramatically over the past 10 years. Barren brome is reported as a problem weed in other winter crops such as oil seed rape, in vineyards and in other cultivated places. In this study, the dormancy and germination under different temperatures, water and light regimes were investigated. Emergence from different depths and persistence in the soil profile were investigated under field conditions. The seeds of Bromus sterilis showed broad ecological valence to hydrothermal factors germinating in the wide range of 5 to 35 °C. Similarly, no strong effect on the germination in an environment with low water potential was observed. The response to light at various temperatures showed that seeds germinated better in darkness. The emergence declined significantly with burial depth (under 40 mm. The loss of primary dormancy was rapid in time and only 50% of the seeds germinated within 8 weeks after collecting from maternal plants. The seeds were not able to survive in the soil seed bank for a longer time and fall seeds lost viability 1 year after burial in a soil profile.

  18. Pyrenophoric acid, a phytotoxic sesquiterpenoid penta-2,4-dienoic acid produced by a potential mycoherbicide, Pyrenophora semeniperda.

    Science.gov (United States)

    Masi, Marco; Meyer, Susan; Cimmino, Alessio; Andolfi, Anna; Evidente, Antonio

    2014-04-25

    A new phytotoxic sesquiterpenoid penta-2,4-dienoic acid, named pyrenophoric acid, was isolated from solid wheat seed culture of Pyrenophora semeniperda, a fungal pathogen proposed as a mycoherbicide for biocontrol of cheatgrass (Bromus tectorum) and other annual bromes. These bromes are serious weeds in winter cereals and also on temperate semiarid rangelands. Pyrenophoric acid was characterized as (2Z,4E)-5-[(7S,9S,10R,12R)-3,4-dihydroxy-2,2,6-trimethylcyclohexyl)]-3-methylpenta-2,4-dienoic acid by spectroscopic and chemical methods. The relative stereochemistry of pyrenophoric acid was assigned using 1H,1H couplings and NOESY experiments, while its absolute configuration was determined by applying the advanced Mosher's method. Pyrenophoric acid is structurally quite closely related to the plant growth regulator abscisic acid. When bioassayed in a cheatgrass coleoptile elongation test at 10(-3) M, pyrenophoric acid showed strong phytotoxicity, reducing coleoptile elongation by 51% relative to the control. In a mixture at 10(-4) M, its negative effect on coleoptile elongation was additive with that of cytochalasin B, another phytotoxic compound found in the wheat seed culture extract of this fungus, demonstrating that the extract toxicity observed in earlier studies was due to the combined action of multiple phytotoxic compounds.

  19. PLUTONIUM UPTAKE AND BEHAVIOR IN PLANTS OF THE DESERT SOUTHWEST: A PRELIMINARY ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, E.; Duff, M.; Ferguson, C.

    2011-03-01

    Eight species of desert vegetation and associated soils were collected from the Nevada National Security Site (N2S2) and analyzed for 238Pu and 239+240Pu concentrations. Amongst the plant species sampled were: atmospheric elemental accumulators (moss and lichen), the very slow growing, long-lived creosote bush and the rapidly growing, short-lived cheatgrass brome. The diversity of growth strategies provided insight into the geochemical behavior and bio-availability of Pu at the N2S2. The highest concentrations of Pu were measured in the onion moss (24.27 Bq kg-1 238Pu and 52.78 Bq kg-1 239+240Pu) followed by the rimmed navel lichen (8.18 Bq kg-1 and 18.4 Bq kg-1 respectively), pointing to the importance of eolian transport of Pu. Brome and desert globemallow accumulated between 3 and 9 times higher concentrations of Pu than creosote and sage brush species. These results support the importance of species specific elemental accumulation strategies rather than exposure duration as the dominant variable influencing Pu concentrations in these plants. Total vegetation elemental concentrations of Ce, Fe, Al, Sm and others were also analyzed. Strong correlations were observed between Fe and Pu. This supports the conclusion that Pu was accumulated as a consequence of the active accumulation of Fe and other plant required nutrients. Cerium and Pu are considered to be chemical analogs. Strong correlations observed in plants support the conclusion that these elements displayed similar geochemical behavior in the environment as it related to the biochemical uptake process of vegetation. Soils were also sampled in association with vegetation samples. This allowed for the calculation of a concentration ratio (CR). The CR values for Pu in plants were highly influenced by the heterogeneity of Pu distribution among sites. Results from the naturally occurring elements of concern were more evenly distributed between sample sites. This allowed for the development of a pattern of plant

  20. Ecophysiology of Trembling Aspen in Response to Root-Zone Conditions and Competition on Reclaimed Mine Soil.

    Science.gov (United States)

    Bockstette, S.; Landhäusser, S.; Pinno, B.; Dyck, M. F.

    2014-12-01

    Reclaimed soils are typically characterized by increased bulk densities, penetration resistances and poor soil structure as well as associated problems with hydrology and aeration. As a result, available rooting space for planted tree seedlings is often restricted to a shallow layer of topsoil, which is usually of higher quality and is cultivated prior to planting. This may hinder the development of healthy root systems, thus drastically increasing the risk for plant stress by limiting access to soil resources such as water, nutrients and oxygen. These problems are exacerbated when herbaceous plants compete for the same resources within this limited root-zone. To understand how limited rooting space affects the physiology of young trees, we experimentally manipulated soil conditions and levels of competition at a reclaimed mine site in central Alberta, Canada. The site was characterized by heavily compacted, fine textured subsoil (~2.0 Mg ha-1), capped with 15 cm of topsoil (~1.5 Mg ha-1). In a replicated study (n=6) half the plots were treated with a subsoil plow to a depth of about 60 cm to increase available rooting spece. Subsequently, trembling aspen (Populus tremuloides Michx.) and smooth brome (Bromus inermis L.) were planted to create four vegetation covers: aspen (a), brome (b), aspen + brome (ab) and control (c) (no vegetation). Various soil properties, including texture, bulk density, penetration resistance and water availability, in conjunction with plant parameters such as root and shoot growth, leaf area development, sap flow, and stomatal conductance have since been monitored, both in-situ and through destructive sampling. Our results indicate that the soil treatment was effective in lowering bulk densities and penetration resistance, while improving moisture retention characteristics. Tree seedling growth and leaf area development were significantly greater without competition, but did not differ between soil treatments. The soil treatment generally

  1. A Quantitative Dynamic Simulation of Bremia lactucae Airborne Conidia Concentration above a Lettuce Canopy.

    Directory of Open Access Journals (Sweden)

    Mamadou Lamine Fall

    Full Text Available Lettuce downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for B. lactucae airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing disease subprocesses (e.g., sporulation and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of independent data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results show an accurate simulation of the trend and shape of B. lactucae temporal dynamics of airborne spore concentration. The model simulated hourly and daily peaks in airborne spore concentrations. More than 95% of the simulation runs, the daily-simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 94% of the simulation runs, the proportion of the linear variation in the hourly-observed values explained by the variation in the hourly-simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is the only dynamic model developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew understanding, forecasting and management.

  2. Genetic dissection of a TIR-NB-LRR locus from the wild North American grapevine species Muscadinia rotundifolia identifies paralogous genes conferring resistance to major fungal and oomycete pathogens in cultivated grapevine.

    Science.gov (United States)

    Feechan, Angela; Anderson, Claire; Torregrosa, Laurent; Jermakow, Angelica; Mestre, Pere; Wiedemann-Merdinoglu, Sabine; Merdinoglu, Didier; Walker, Amanda R; Cadle-Davidson, Lance; Reisch, Bruce; Aubourg, Sebastien; Bentahar, Nadia; Shrestha, Bipna; Bouquet, Alain; Adam-Blondon, Anne-Françoise; Thomas, Mark R; Dry, Ian B

    2013-11-01

    The most economically important diseases of grapevine cultivation worldwide are caused by the fungal pathogen powdery mildew (Erysiphe necator syn. Uncinula necator) and the oomycete pathogen downy mildew (Plasmopara viticola). Currently, grapegrowers rely heavily on the use of agrochemicals to minimize the potentially devastating impact of these pathogens on grape yield and quality. The wild North American grapevine species Muscadinia rotundifolia was recognized as early as 1889 to be resistant to both powdery and downy mildew. We have now mapped resistance to these two mildew pathogens in M. rotundifolia to a single locus on chromosome 12 that contains a family of seven TIR-NB-LRR genes. We further demonstrate that two highly homologous (86% amino acid identity) members of this gene family confer strong resistance to these unrelated pathogens following genetic transformation into susceptible Vitis vinifera winegrape cultivars. These two genes, designated resistance to Uncinula necator (MrRUN1) and resistance to Plasmopara viticola (MrRPV1) are the first resistance genes to be cloned from a grapevine species. Both MrRUN1 and MrRPV1 were found to confer resistance to multiple powdery and downy mildew isolates from France, North America and Australia; however, a single powdery mildew isolate collected from the south-eastern region of North America, to which M. rotundifolia is native, was capable of breaking MrRUN1-mediated resistance. Comparisons of gene organization and coding sequences between M. rotundifolia and the cultivated grapevine V. vinifera at the MrRUN1/MrRPV1 locus revealed a high level of synteny, suggesting that the TIR-NB-LRR genes at this locus share a common ancestor. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  3. The Arabidopsis microtubule-associated protein MAP65-3 supports infection by filamentous biotrophic pathogens by down-regulating salicylic acid-dependent defenses.

    Science.gov (United States)

    Quentin, Michaël; Baurès, Isabelle; Hoefle, Caroline; Caillaud, Marie-Cécile; Allasia, Valérie; Panabières, Franck; Abad, Pierre; Hückelhoven, Ralph; Keller, Harald; Favery, Bruno

    2016-03-01

    The oomycete Hyaloperonospora arabidopsidis and the ascomycete Erysiphe cruciferarum are obligate biotrophic pathogens causing downy mildew and powdery mildew, respectively, on Arabidopsis. Upon infection, the filamentous pathogens induce the formation of intracellular bulbous structures called haustoria, which are required for the biotrophic lifestyle. We previously showed that the microtubule-associated protein AtMAP65-3 plays a critical role in organizing cytoskeleton microtubule arrays during mitosis and cytokinesis. This renders the protein essential for the development of giant cells, which are the feeding sites induced by root knot nematodes. Here, we show that AtMAP65-3 expression is also induced in leaves upon infection by the downy mildew oomycete and the powdery mildew fungus. Loss of AtMAP65-3 function in the map65-3 mutant dramatically reduced infection by both pathogens, predominantly at the stages of leaf penetration. Whole-transcriptome analysis showed an over-represented, constitutive activation of genes involved in salicylic acid (SA) biosynthesis, signaling, and defense execution in map65-3, whereas jasmonic acid (JA)-mediated signaling was down-regulated. Preventing SA synthesis and accumulation in map65-3 rescued plant susceptibility to pathogens, but not the developmental phenotype caused by cytoskeleton defaults. AtMAP65-3 thus has a dual role. It positively regulates cytokinesis, thus plant growth and development, and negatively interferes with plant defense against filamentous biotrophs. Our data suggest that downy mildew and powdery mildew stimulate AtMAP65-3 expression to down-regulate SA signaling for infection.

  4. Evidence for a race-specific resistance factor in some lettuce (Lactuca sativa L.) cultivars previously considered to be universally susceptible to Bremia lactucae regel.

    Science.gov (United States)

    Crute, I R; Lebeda, A

    1981-05-01

    Previously undetected race-specific resistance to Bremia lactucae (downy mildew) was located in many lettuce cultivars hitherto considered to be universally susceptible to this disease. This resistance factor(s) may also be widely distributed in other cultivars known to carry combinations of already recognised factors R1 to R11. Specific virulence to match this resistance is almost invariably present in pathogen collections. This situation may be either a relic of the evolutionary history of the B. lactucae - L. sativa asssociation or may reflect a rare mutation in B. lactucae for avirulence on all but a few specialised L. sativa genotypes.

  5. 黑龙江省抱子甘蓝常见病害的发生与防治%Occurrence and Control of Brussels sprouts Common Diseases in Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    刘天红

    2015-01-01

    介绍抱子甘蓝常见病害的发生特点及防治方法,包括菌核病、霜霉病、软腐病、黑腐病,以为抱子甘蓝病害的防治提供参考.%Feature and control methods of Brussels sprouts common diseases were introduced which included sclerotinia,downy mildew,soft rot disease,black rot disease,in order to provide references for Brussels sprouts disease prevention and control.

  6. Elevated genetic diversity in an F2:6 population of quinoa (Chenopodium quinoa) developed through an inter-ecotype cross

    DEFF Research Database (Denmark)

    Benlhabib, Ouafae; Boujartani, Noura; Maughan, Peter J

    2016-01-01

    . The purpose was to characterize the quinoa germplasm developed, to assess the discriminating potential of 21 agro-morpho-phenological traits, and to evaluate the extent of genetic variability recovered through selfing. A vast amount of genetic variation was detected among the 72 lines evaluated......, and resistance to downy mildew. In the Principal Component analysis, the first axis explained 74% of the total variation and was correlated to plant height, panicle size, stem diameter, biomass, mildew reaction, maturation, and seed yield; those traits are relevant discriminatory characters. Yield correlated...

  7. Economic issues and perspectives on innovation in new resistant grapevine varieties in France

    Directory of Open Access Journals (Sweden)

    Montaigne Etienne

    2016-12-01

    Full Text Available The arrival in France of new varieties resistant to downy mildew and powdery mildew calls into question the aims of this “revolution” in a sector dominated by tradition. The proposed evaluation reviews the historical experience of cross-breeding programmes from an evolutionist standpoint before analysing the responses to the new technological paradigm of resistance to disease. Taking account of the time periods, dating their implementation and describing the opportunities open to winemakers, the paper revisits the scientific controversies, the institutional blockages to be eliminated, the means of recognition and the prospects.

  8. The 'Big bang' in the Early Iron Age

    Directory of Open Access Journals (Sweden)

    Medović Aleksandar

    2010-01-01

    Full Text Available The Early Iron Age granaries of Tell Gradina upon Bosut exploded in a fire inferno in the 8th century B.C. The result of this catastrophe is 2-5 cm thick layer with mixed carbonized seeds and fruits. Recently, eight samples were taken from Gradina's profile for archaeobotanical analysis. The goal was to obtain basic information on land use and on major crops and weeds of that period. The most abundant were cereals, followed by millets, pulses and oil/fibre plants. The dominant cereals were einkorn (Triticum monococcum and hulled barley (Hordeum vulgare vulgare. Broomcorn millet (Panicum miliaceum was also very important. Pulses were represented with six and oil/fibre plants with three species. Among weeds and ruderals, most common are rye brome (Bromus secalinus, fat hen (Chenopodium album, darnel ryegrass (Lolium temulentum, hairy crabgrass (Digitaria sanguinalis and corncockle (Agrostemma githago.

  9. Nano and micro reoriented domains and their relation with the crystal structure in the new ferroelectric boracite Zn{sub 3}B{sub 7}O{sub 13}Br

    Energy Technology Data Exchange (ETDEWEB)

    Campa-Molina, J [Centro Universitario de la Cienega, Universidad de Guadalajara, Laboratorio de Materiales, Avenida Universidad No. 1115, Colonia Linda Vista, CP 47840, Ocotlan, Jalisco (Mexico); Ulloa-Godinez, S [Centro Universitario de la Cienega, Universidad de Guadalajara, Laboratorio de Materiales, Avenida Universidad No. 1115, Colonia Linda Vista, CP 47840, Ocotlan, Jalisco (Mexico); Barrera, A [Centro Universitario de la Cienega, Universidad de Guadalajara, Laboratorio de Materiales, Avenida Universidad No. 1115, Colonia Linda Vista, CP 47840, Ocotlan, Jalisco (Mexico); Bucio, L [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico, DF (Mexico); Mata, J [Centro de Ciencias de la Materia Condensada, UNAM, Apartado Postal 2681, E-22800, Ensenada, BC (Mexico)

    2006-05-24

    A new zinc brome boracite Zn{sub 3}B{sub 7}O{sub 13}Br has been grown by a chemical transport reaction in closed quartz ampoules at 920 K. The crystal structure was characterized by Rietveld refinement. Ferroelectric nano and micro reorientable domains were found in this material using polarizing optical microscopy (PLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Chemical analysis was performed with x-ray energy dispersive spectroscopy (EDX). In the crystal, a new structure transition at 586 K from orthorhombic (Pca 2{sub 1}) to cubic cell (F4-bar3c) has been found. This transition was corroborated by differential scanning calorimetry (DSC)

  10. 17O NMR parameters of some substituted benzyl ethers components: Ab initio study

    Directory of Open Access Journals (Sweden)

    Mahdi Rezaei Sameti

    2016-09-01

    Full Text Available The 17O NMR chemical shielding tensors and chemical shift for a set of substituted benzyl ethers derivatives containing (methyl, ethyl, isopropyl, t-butyl, brome and lithium have been calculated. The molecular structures were fully optimized using B3LYP/6-31G(d,p. The calculation of the 17O shielding tensors employed the GAUSSIAN 98 implementation of the gauge-including atomic orbital (GIAO and continuous set of gauge transformations (CSGT by using 6-31G (d,p, 6-31++G(d,p and 6-311++G(d,p basis set methods at density functional levels of theories (DFT. The values determined using the GIAO and CSGT were found to give a good agreement with the experimental chemical shielding.

  11. The influence of cover crops and tillage on actual and potential soil erosion in an olive grove

    Science.gov (United States)

    Sastre, Blanca; Bienes, Ramón; García-Díaz, Andrés; Panagopoulos, Thomas; José Marqués, Maria

    2014-05-01

    The study was carried out in an olive grove in central Spain (South of Madrid; Tagus River Basin). In this semi-arid zone, the annual mean temperature is 13.8 ºC and the annual precipitation is 395 mm. Olive groves are planted in an erosion prone area due to steep slopes up to 15%. Soil is classified as Typic Haploxerept with clay loam texture. The land studied was formerly a vineyard, but it was replaced by the studied olive grove in 2004. It covers approximately 3 ha and olive trees are planted every 6 x 7 metres. They were usually managed by tillage to decrease weed competition. This conventional practice results in a wide surface of bare soil prone to erosion processes. In the long term soil degradation may lead to increase the desertification risk in the area. Storms have important consequences in this shallow and vulnerable soil, as more than 90 Mg ha-1 have been measured after one day with 40 mm of rainfall. In order to avoid this situation, cover crops between the olive trees were planted three years ago: sainfoin (Onobrychis viciifolia), barley (Hordeum vulgare), and purple false brome (Brachypodium distachyon), and they were compared with annual spontaneous vegetation after a minimum tillage treatment (ASV). The results regarding erosion control were positive. We observed (Oct. 2012/Sept. 2013) annual soil loss up to 11 Mg ha-1 in ASV, but this figure was reduced in the sown covers, being 8 Mg ha-1 in sainfoin treatment, 3,7 Mg ha-1 in barley treatment, and only 1,5 Mg ha-1 in false brome treatment. Those results are used to predict the risk of erosion in long term. Moreover, soil organic carbon (SOC) increased with treatments, this is significant as it reduces soil erodibility. The increases were found both in topsoil (up to 5 cm) and more in depth, in the root zone (from 5 to 10 cm depth). From higher to lower SOC values we found the false brome (1.05%), barley (0.92%), ASV (0.79%) and sainfoin (0.71%) regarding topsoil. In the root zone (5-10 cm depth

  12. 忻州市优良牧草品种营养价值及经济效益分析

    Institute of Scientific and Technical Information of China (English)

    李向红

    2014-01-01

    羊业先行,众畜兴旺;畜牧发展,牧草先行。对优良牧草紫花苜蓿、沙打旺、无芒雀麦、高丹草、蕥玉8号青贮玉米、黑麦草、籽粒苋的营养价值及经济效益进行分析比对,并提出种植推广建议。%The sheep industry first, and livestock husbandry development, forage first prosperity. The economic benefits and the nutritional values of forage grass, including Astragalus adsurgens, alfalfa awnless brome, Sudan grass, Yayu 8 silage maize, ryegrass and amaranth, are analyzed, and the cultivate promotion recommendations are put forward.

  13. Biological activity of the humus horizon of ordinary chernozems as an indicator of the ecological state of agroecosystems in Bashkortostan

    Science.gov (United States)

    Khasanova, R. F.; Suyundukov, Ya. T.; Semenova, I. N.

    2014-08-01

    A comparative analysis of the biological activity has been performed in the soils of Transural Bashkiria developing under natural perennial grasses and under sown herbs. It is shown that the structure of the microbial community in the soils under natural perennial grasses (fescue, brome grass, and couch grass) prevents the removal of nitrogen from the ecosystem and favors nitrogen fixation in the microbial pool of the trophic chain. The method of multisubstrate testing points to certain differences between the metabolic potentials of the microbial communities of the soils under natural grasses and sown herbs. The high values of the integral index of health of the microbial system in the soils under natural perennial grasses attests to their efficiency in sustaining the soil fertility.

  14. Comparison of selected parameters of biomass and coal

    Science.gov (United States)

    Lalak, Justyna; Martyniak, Danuta; Kasprzycka, Agnieszka; Żurek, Grzegorz; Moroń, Wojciech; Chmielewska, Mariola; Wiącek, Dariusz; Tys, Jerzy

    2016-10-01

    As a fuel, biomass differs in its properties from fossil fuels and acquisition thereof for energy purposes is limited; hence, the ongoing search for new bioenergetically useful plants. The article presents the results of physical and chemical analyses of seven species of perennial grasses: tall wheatgrass, tall wheatgrass `Bamar', brome grass, tall fescue ecotype, reed canary grass, giant miscanthus, and sorghum. The research involved technical and elemental analysis as well as analysis of the ash composition performed in order to determine their potential use for combustion process. The measurement results were compared with those obtained for hard coal and agricultural biomass, which is widely used in the energy industry. The results suggest that perennial grasses can successfully be combusted with similar performance to coal if burned in appropriate combustion installations.

  15. Caracterização morfo-histoquímica da germinação e o desenvolvimento pós-seminal in vitro e formação de culturas nodulares em Vriesea friburgensis Mez var. paludosa (L.B. Smith) L.B. Smith E Vriesea reitzii Leme

    OpenAIRE

    Prado,Jenny Paola Corredor

    2012-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Recursos Genéticos Vegetais O progressivo processo de devastação da Mata Atlântica, e os efeitos ornamentais e paisagísticos das bromélias, têm ocasionado a diminuição de suas populações até ter atualmente muitas espécies sob ameaça de extinção. Assim, considerando a importância das Bromeliáceas no cenário nacional, bem como, da conservação da biodiversidade faz-se nec...

  16. Gerenciamento de resíduos químicos e águas servidas no laboratório de isótopos estáveis do CENA/USP Chemistry waste and residues waters management at the stable isotope laboratory of the CENA/USP

    Directory of Open Access Journals (Sweden)

    José Albertino Bendassolli

    2003-08-01

    Full Text Available A system for disposal and recovery of the main effluents and chemical waist from isotope separation plants and enriched compounds-15N and 34S production has been carried out at the Stable Isotope Laboratory (LIE of the CENA/USP. Around four hundred thousand liters of effluents has been recovered yearly. Among the recovered chemical wastes, the more relevant are: ammonia; brome; ammonium and sodium sulfate; sodium hydroxide; sulfur dioxide; and hydrochloric acid. Chemical wastes containg recoverable heavy metals (Ag, Cr and Cu and solvents (methanol, ethanol and acetone are processed and recovered. Gaseous emissions, mainly H2S are used for recovery of heavy metals solutions. The minimization of the residues waters, as well the reduction of electric energy consume was established using a water deionization system. A cost/effect balance of the process is reported.

  17. Radiobiological and genetic effects of Bromus inermis seed progeny from populations of the East-Ural Radioactive Trace (Russia, Kyshtym accident) - Radiobiological and genetic effects for Bromus inermis Leyss. Populations at the East-Ural radioactive trace (Russia, Kyshtym accident in 1957)

    Energy Technology Data Exchange (ETDEWEB)

    Antonova, Elena V.; Pozolotna, Vera N. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Karimullina, Elina M. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Department of Developmental and Cell Biology, University of California, 2011 Biological Sciences III, Irvine, CA 92697-2300 (United States); Roeder, Marion S. [Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, D-06466, Gatersleben (Germany)

    2014-07-01

    This investigation dedicates the problem of remote consequences of radiation impact on plant populations. This is a part of a complex research, which includes the classic triad of radioecology (Timofeev-Ressovsky 1963): 'accumulation and migration of radionuclides in different components of ecosystems - assessment of radiation dose - investigation of radiobiological effects'. We used the populations of smooth brome (Bromus inermis Leyss.) as a model system for the investigation of radiobiological and genetic effects. It is radiosensitive plant (Preobrazhenskaya 1971). These species may be used as objects for bio-indication at the radioactive contaminated areas, and as well as large-scale radioecological studies, because the adaptation processes are faster for radiosensitive species (Shevchenko et al., 1992; Pozolotina et al. 2005). We calculated external and internal whole-body dose rates by ERICA Tool (Karimullina et al., 2013). The total dose rate for brome was under 100 mGy h{sup -1} at the most polluted site but 43-110 times (Tier 3) exceeded the background along the pollution gradient. Therefore it can be concluded that herbaceous plant populations currently exist under low level chronic exposure at the EURT area. During seven years we have studied variability of viability, mutability and radioresistance of brome seed progeny. The combined effects of radiation exposure and weather conductions at the EURT area were absent. It may be connect with wide variability of inter-population test parameters. At the same time the weather conductions had an influence on the quality of seed progeny at the background area. We analyzed also correlation between original viability and radioresistance of seed progeny from the all plots. This dependence was positive. It was shown negative dependence between original viability of seed progeny and low weight molecular antioxidants content too. Ionizing radiation is a mutagenic factor and, accordingly, elevated mutation

  18. Soil Seed Bank Responses to Postfire Herbicide and Native Seeding Treatments Designed to Control Bromus tectorum in a Pinyon–Juniper Woodland at Zion National Park, USA

    Science.gov (United States)

    Brooks, Matthew L.; Hondo Brisbin, graduate student; Andrea Thode, Associate Professor; Karen Weber, graduate student

    2013-01-01

    The continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.

  19. VineSens: An Eco-Smart Decision-Support Viticulture System.

    Science.gov (United States)

    Pérez-Expósito, Josman P; Fernández-Caramés, Tiago M; Fraga-Lamas, Paula; Castedo, Luis

    2017-02-25

    This article presents VineSens, a hardware and software platform for supporting the decision-making of the vine grower. VineSens is based on a wireless sensor network system composed by autonomous and self-powered nodes that are deployed throughout a vineyard. Such nodes include sensors that allow us to obtain detailed knowledge on different viticulture processes. Thanks to the use of epidemiological models, VineSens is able to propose a custom control plan to prevent diseases like one of the most feared by vine growers: downy mildew. VineSens generates alerts that warn farmers about the measures that have to be taken and stores the historical weather data collected from different spots of the vineyard. Such data can then be accessed through a user-friendly web-based interface that can be accessed through the Internet by using desktop or mobile devices. VineSens was deployed at the beginning in 2016 in a vineyard in the Ribeira Sacra area (Galicia, Spain) and, since then, its hardware and software have been tested to prevent the development of downy mildew, showing during its first season that the system can led to substantial savings, to decrease the amount of phytosanitary products applied, and, as a consequence, to obtain a more ecologically sustainable and healthy wine.

  20. VineSens: An Eco-Smart Decision-Support Viticulture System

    Directory of Open Access Journals (Sweden)

    Josman P. Pérez-Expósito

    2017-02-01

    Full Text Available This article presents VineSens, a hardware and software platform for supporting the decision-making of the vine grower. VineSens is based on a wireless sensor network system composed by autonomous and self-powered nodes that are deployed throughout a vineyard. Such nodes include sensors that allow us to obtain detailed knowledge on different viticulture processes. Thanks to the use of epidemiological models, VineSens is able to propose a custom control plan to prevent diseases like one of the most feared by vine growers: downy mildew. VineSens generates alerts that warn farmers about the measures that have to be taken and stores the historical weather data collected from different spots of the vineyard. Such data can then be accessed through a user-friendly web-based interface that can be accessed through the Internet by using desktop or mobile devices. VineSens was deployed at the beginning in 2016 in a vineyard in the Ribeira Sacra area (Galicia, Spain and, since then, its hardware and software have been tested to prevent the development of downy mildew, showing during its first season that the system can led to substantial savings, to decrease the amount of phytosanitary products applied, and, as a consequence, to obtain a more ecologically sustainable and healthy wine.

  1. Optimization of the Extraction of Anthocyanins from the Fruit Skin of Rhodomyrtus tomentosa (Ait. Hassk and Identification of Anthocyanins in the Extract Using High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS

    Directory of Open Access Journals (Sweden)

    Yuan-Ming Sun

    2012-05-01

    Full Text Available Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants. In this study, the extraction of anthocyanins from freeze-dried fruit skin of downy rose-myrtle (Rhodomyrtus tomentosa (Ait. Hassk var. Gangren was optimized using response surface methodology (RSM. Using 60% ethanol containing 0.1% (v/v hydrochloric acid as extraction solvent, the optimal conditions for maximum yields of anthocyanin (4.358 ± 0.045 mg/g were 15.7:1 (v/w liquid to solid ratio, 64.38 °C with a 116.88 min extraction time. The results showed good fits with the proposed model for the anthocyanin extraction (R2 = 0.9944. Furthermore, the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS analysis of the anthocyanins extracted from the fruit skin of downy rose-myrtle revealed the presence of five anthocyanin components, which were tentatively identified as delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside.

  2. Imbalanced Lignin Biosynthesis Promotes the Sexual Reproduction of Homothallic Oomycete Pathogens

    Science.gov (United States)

    Quentin, Michaël; Allasia, Valérie; Pegard, Anthony; Allais, Florent; Ducrot, Paul-Henri; Favery, Bruno; Levis, Caroline; Martinet, Sophie; Masur, Clarissa; Ponchet, Michel; Roby, Dominique; Schlaich, Nikolaus L.; Jouanin, Lise; Keller, Harald

    2009-01-01

    Lignin is incorporated into plant cell walls to maintain plant architecture and to ensure long-distance water transport. Lignin composition affects the industrial value of plant material for forage, wood and paper production, and biofuel technologies. Industrial demands have resulted in an increase in the use of genetic engineering to modify lignified plant cell wall composition. However, the interaction of the resulting plants with the environment must be analyzed carefully to ensure that there are no undesirable side effects of lignin modification. We show here that Arabidopsis thaliana mutants with impaired 5-hydroxyguaiacyl O-methyltransferase (known as caffeate O-methyltransferase; COMT) function were more susceptible to various bacterial and fungal pathogens. Unexpectedly, asexual sporulation of the downy mildew pathogen, Hyaloperonospora arabidopsidis, was impaired on these mutants. Enhanced resistance to downy mildew was not correlated with increased plant defense responses in comt1 mutants but coincided with a higher frequency of oomycete sexual reproduction within mutant tissues. Comt1 mutants but not wild-type Arabidopsis accumulated soluble 2-O-5-hydroxyferuloyl-l-malate. The compound weakened mycelium vigor and promoted sexual oomycete reproduction when applied to a homothallic oomycete in vitro. These findings suggested that the accumulation of 2-O-5-hydroxyferuloyl-l-malate accounted for the observed comt1 mutant phenotypes during the interaction with H. arabidopsidis. Taken together, our study shows that an artificial downregulation of COMT can drastically alter the interaction of a plant with the biotic environment. PMID:19148278

  3. A De Novo-Assembly Based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies.

    Science.gov (United States)

    Guo, Li; Allen, Kelly S; Deiulio, Greg; Zhang, Yong; Madeiras, Angela M; Wick, Robert L; Ma, Li-Jun

    2016-01-01

    Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by next generation sequencing of mixed host and pathogen RNA (i.e., metatranscriptomics). We applied this pipeline to metatranscriptomic sequencing data of sweet basil (Ocimum basilicum) and its obligate downy mildew parasite Peronospora belbahrii, both lacking a sequenced genome. Even with a single data point, we were able to identify both candidate host defense genes and pathogen virulence genes that are highly expressed during infection. This demonstrates the power of this pipeline for identifying genes important in host-pathogen interactions without prior genomic information for either the plant host or the obligate biotrophic pathogen. The simplicity of this pipeline makes it accessible to researchers with limited computational skills and applicable to metatranscriptomic data analysis in a wide range of plant-obligate-parasite systems.

  4. Extreme size and sequence variation in the ITS rDNA of Bremia lactucae.

    Science.gov (United States)

    Choi, Young-Joon; Hong, Seung-Boem; Shin, Hyeon-Dong

    2007-02-01

    Bremia lactucae Regel (Chromista, Peronosporaceae) is an economically destructive pathogen, which causes downy mildew disease on lettuce (Lactuca sativa L.) worldwide. The ribosomal internal transcribed spacer (ITS) of Bremia lactucae isolates was analyzed for the first time. The ITS region of lettuce downy mildew was observed to have a size of 2458 bp; thereby, having one of the longest ITS sizes recorded to date. The majority of the extremely large sized ITS2 length of 2086 was attributed to the additional presences of nine repetitive elements with lengths of 179-194 bp, which between them shared the low homology of 48-69%. Comparison of the ITS2 sequences with the B. lactucae isolates from other host plants showed that isolates present on Lactuca sativa were distinct from those on L. indica var. laciniata, as well as Hemistepta and Youngia. We suggest the high degree of sequence heterogeneity exhibited in the ITS2 region of B. lactucae may warrant the specific detection and diagnosis of this destructive pathogen or its division into several distinct species.

  5. Optimization of the extraction of anthocyanins from the fruit skin of Rhodomyrtus tomentosa (Ait.) Hassk and identification of anthocyanins in the extract using High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS).

    Science.gov (United States)

    Liu, Guo-Ling; Guo, Hong-Hui; Sun, Yuan-Ming

    2012-01-01

    Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants. In this study, the extraction of anthocyanins from freeze-dried fruit skin of downy rose-myrtle (Rhodomyrtus tomentosa (Ait.) Hassk var. Gangren) was optimized using response surface methodology (RSM). Using 60% ethanol containing 0.1% (v/v) hydrochloric acid as extraction solvent, the optimal conditions for maximum yields of anthocyanin (4.358 ± 0.045 mg/g) were 15.7:1 (v/w) liquid to solid ratio, 64.38 °C with a 116.88 min extraction time. The results showed good fits with the proposed model for the anthocyanin extraction (R(2) = 0.9944). Furthermore, the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) analysis of the anthocyanins extracted from the fruit skin of downy rose-myrtle revealed the presence of five anthocyanin components, which were tentatively identified as delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside.

  6. Imbalanced lignin biosynthesis promotes the sexual reproduction of homothallic oomycete pathogens.

    Directory of Open Access Journals (Sweden)

    Michaël Quentin

    2009-01-01

    Full Text Available Lignin is incorporated into plant cell walls to maintain plant architecture and to ensure long-distance water transport. Lignin composition affects the industrial value of plant material for forage, wood and paper production, and biofuel technologies. Industrial demands have resulted in an increase in the use of genetic engineering to modify lignified plant cell wall composition. However, the interaction of the resulting plants with the environment must be analyzed carefully to ensure that there are no undesirable side effects of lignin modification. We show here that Arabidopsis thaliana mutants with impaired 5-hydroxyguaiacyl O-methyltransferase (known as caffeate O-methyltransferase; COMT function were more susceptible to various bacterial and fungal pathogens. Unexpectedly, asexual sporulation of the downy mildew pathogen, Hyaloperonospora arabidopsidis, was impaired on these mutants. Enhanced resistance to downy mildew was not correlated with increased plant defense responses in comt1 mutants but coincided with a higher frequency of oomycete sexual reproduction within mutant tissues. Comt1 mutants but not wild-type Arabidopsis accumulated soluble 2-O-5-hydroxyferuloyl-L-malate. The compound weakened mycelium vigor and promoted sexual oomycete reproduction when applied to a homothallic oomycete in vitro. These findings suggested that the accumulation of 2-O-5-hydroxyferuloyl-L-malate accounted for the observed comt1 mutant phenotypes during the interaction with H. arabidopsidis. Taken together, our study shows that an artificial downregulation of COMT can drastically alter the interaction of a plant with the biotic environment.

  7. Five New Records of Orchidaceae from Hainan, China%海南兰科植物新记录5种

    Institute of Scientific and Technical Information of China (English)

    田怀珍; 董全英; 李星霖

    2012-01-01

    Five orchid species:Aphyllorchis caudata Rolfe ex Downie,Didymoplexis vietnamica Ormerod,Pinalia amica (H.G.Reichenbach) Kuntze,Zeuxine agyokuma Fukuyama and Z.sakagutii Tuyama.are newly recorded from Hainan Island.Aphyllorchis caudata and Didymoplexis vietnamica are saprophytic,Pinalia amica is epiphytic and Zeuxine agyokuana and Z.sakagutii are terrestrial orchids.All specimens are deposited at the Herbarium of East China Normal University (HSNU).%报道了5个海南兰科植物新记录种:尾萼无叶兰(Aphyllorchis cuadata Rolfe ex Downie)、中越双唇兰(Didymoplexis vietnamica Ormerod)、粗茎苹兰[Pinalia amica(H.G.Reichenbach)Kuntze]、绿叶线柱兰(Zeuxine agyokuana Fukuyama)和黄唇线柱兰(Z.sakagutii Tuyama.).其中尾萼无叶兰和中越双唇兰为腐生兰,粗茎苹兰为附生兰,绿叶线柱兰与黄唇线柱兰为地生种类.凭证标本均保存于华东师范大学生物学系植物标本馆(HSNU).

  8. A de-novo-assembly-based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies

    Directory of Open Access Journals (Sweden)

    Li Guo

    2016-07-01

    Full Text Available Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by next generation sequencing of mixed host and pathogen RNA (i.e. metatranscriptomics. We applied this pipeline to metatranscriptomic sequencing data of sweet basil (Ocimum basilicum and its obligate downy mildew parasite Peronospora belbahrii, both lacking a sequenced genome. Even with a single data point, we were able to identify both candidate host defense genes and pathogen virulence genes that are highly expressed during infection. This demonstrates the power of this pipeline for identifying genes important in host-pathogen interactions without prior genomic information for either the plant host or the obligate biotrophic pathogen. The simplicity of this pipeline makes it accessible to researchers with limited computational skills and applicable to metatranscriptomic data analysis in a wide range of plant-obligate-parasite systems.

  9. A De Novo-Assembly Based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies

    Science.gov (United States)

    Guo, Li; Allen, Kelly S.; Deiulio, Greg; Zhang, Yong; Madeiras, Angela M.; Wick, Robert L.; Ma, Li-Jun

    2016-01-01

    Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by next generation sequencing of mixed host and pathogen RNA (i.e., metatranscriptomics). We applied this pipeline to metatranscriptomic sequencing data of sweet basil (Ocimum basilicum) and its obligate downy mildew parasite Peronospora belbahrii, both lacking a sequenced genome. Even with a single data point, we were able to identify both candidate host defense genes and pathogen virulence genes that are highly expressed during infection. This demonstrates the power of this pipeline for identifying genes important in host–pathogen interactions without prior genomic information for either the plant host or the obligate biotrophic pathogen. The simplicity of this pipeline makes it accessible to researchers with limited computational skills and applicable to metatranscriptomic data analysis in a wide range of plant-obligate-parasite systems. PMID:27462318

  10. [Epigenetic variability induced by nicotinic acid in Triticum aestivum L].

    Science.gov (United States)

    Bogdanova, E D

    2003-09-01

    The effect of nicotinic acid (NA) on hereditary traits of spring common wheat cultivar Kazakhstanskaya 126 (K.126) were studied under the laboratory and field conditions. Treatment of seeds and vegetating plants with 0.01-0.1% NA (aqueous solution) induced heritable epigenetic changes in wheat. As a result, strong tall plants with the long productive spike, large seeds, and several quantitative and qualitative characters other than in the original cultivar were obtained in the second and further generations after treatment. Crosses of changed plants with each other did not result in segregation with respect to leaf downiness or anthocyan stem color in F2-F4, suggesting the same epigenetic state of genes responsible for changed characters. In crosses with the original cultivar, characters of the changed plants always dominated in F1. Basing on the current views, the changes were attributed to a transition of the hl1 and pc recessive marker genes into new, dominant epiallelic states Hl1 and Pc, which respectively determine downy leaves and the colored stem. The NA effect was specific, since only one type of the variation was observed. The changed characters were stable, and no reversion to the original phenotype was detected in 57 generations.

  11. Hidden keys to survival: the type, density, pattern and functional role of emperor penguin body feathers.

    Science.gov (United States)

    Williams, Cassondra L; Hagelin, Julie C; Kooyman, Gerald L

    2015-10-22

    Antarctic penguins survive some of the harshest conditions on the planet. Emperor penguins breed on the sea ice where temperatures drop below -40°C and forage in -1.8°C waters. Their ability to maintain 38°C body temperature in these conditions is due in large part to their feathered coat. Penguins have been reported to have the highest contour feather density of any bird, and both filoplumes and plumules (downy feathers) are reported absent in penguins. In studies modelling the heat transfer properties and the potential biomimetic applications of penguin plumage design, the insulative properties of penguin plumage have been attributed to the single afterfeather attached to contour feathers. This attribution of the afterfeather as the sole insulation component has been repeated in subsequent studies. Our results demonstrate the presence of both plumules and filoplumes in the penguin body plumage. The downy plumules are four times denser than afterfeathers and play a key, previously overlooked role in penguin survival. Our study also does not support the report that emperor penguins have the highest contour feather density.

  12. Effect of silicates and electrical conductivity on Fusarium wilt of hydroponically grown lettuce.

    Science.gov (United States)

    Chitarra, W; Pugliese, M; Gilardi, G; Gullino, M L; Garibaldi, A

    2013-01-01

    Silicon can stimulate natural defense mechanisms in plants, reducing foliar diseases like powdery arid downy mildew on several crops, including lettuce. The effect of silicate on Fusarium wilt, caused by Fusarium oxysporum f. sp. lactucae was evaluated under greenhouse conditions on lettuce grown in soilless systems. Silicon, as potassium silicate, was added at 100 mg L(-1) of nutrient solution at three levels of electrical conductivity; 1.5-1.6 mS cm(-1) (E.C.1), 3.0-3.2 mS cm(-1) (E.C.2) and 4-4.2 mS cm(-1) (E.C.3). Pots containing lettuce plants were first inoculated with F. oxysporum f. sp. lactucae (3x10(5) chlamidospores ml(-1)) 15-20 days before transplanting. Disease severity and physiological parameters, including chlorophyll content, were analyzed weekly after transplanting. The addition of potassium silicate slightly reduced Fusarium wilt, at all levels of electrical conductivity under study, compared to the control. On the contrary, the increase of electrical conductivity of the nutrient solution showed no effect on the disease. The use of silicon was previously demonstrated to significantly reduce downy mildew on lettuce in soilless systems, and in this trial it demonstrated to slightly reduce disease severity of an important soil-borne pathogen like F. oxysporum f. sp. lactucae, suggesting the possibility to apply it successfully in soilless crops.

  13. Observations on the Behaviour of Different Populations of Plasmopara viticola Resistant to QoI Fungicides in Italian Vineyards

    Directory of Open Access Journals (Sweden)

    M.L. Gullino

    2004-12-01

    Full Text Available Grapevine downy mildew, caused by Plasmopara viticola, is probably the most damaging fungal disease of grapevine world-wide. Among the fungicides recently developed for downy mildew control is the QoI class of fungicides, which inhibits mitochondrial respiration. Since 1999, selected P. viticola populations in northern Italy have been monitored for resistance to QoI fungicides. Detached leaf discs and whole potted plants were used under controlled conditions to test the sampled populations. QoI-resistant populations of P. viticola were found in all the vineyards sampled in 2001 and 2002 in Trentino Alto Adige and Friuli Venezia Giulia, where failure in QoI control was reported. Many of the populations had minimum inhibition concentration (MIC values 3– 30 times higher than those of sensitive reference populations. Populations of P. viticola sampled from vineyards in Piedmont, where no QoI fungicides had previously been used, showed MIC values equal to, or lower than those of the reference populations. Most of the P. viticola populations collected in Trentino Alto Adige in 2001 showed high virulence in leaf disc test and were not controlled by QoI fungicides, applied both at field and double field rates in the whole plant test. Most of these populations retained their virulence in the subsequent leaf disc test in water.

  14. VineSens: An Eco-Smart Decision-Support Viticulture System

    Science.gov (United States)

    Pérez-Expósito, Josman P.; Fernández-Caramés, Tiago M.; Fraga-Lamas, Paula; Castedo, Luis

    2017-01-01

    This article presents VineSens, a hardware and software platform for supporting the decision-making of the vine grower. VineSens is based on a wireless sensor network system composed by autonomous and self-powered nodes that are deployed throughout a vineyard. Such nodes include sensors that allow us to obtain detailed knowledge on different viticulture processes. Thanks to the use of epidemiological models, VineSens is able to propose a custom control plan to prevent diseases like one of the most feared by vine growers: downy mildew. VineSens generates alerts that warn farmers about the measures that have to be taken and stores the historical weather data collected from different spots of the vineyard. Such data can then be accessed through a user-friendly web-based interface that can be accessed through the Internet by using desktop or mobile devices. VineSens was deployed at the beginning in 2016 in a vineyard in the Ribeira Sacra area (Galicia, Spain) and, since then, its hardware and software have been tested to prevent the development of downy mildew, showing during its first season that the system can led to substantial savings, to decrease the amount of phytosanitary products applied, and, as a consequence, to obtain a more ecologically sustainable and healthy wine. PMID:28245619

  15. Preliminary investigation of diseases on new extensive soybean varieties in Guangdong Province%广东省新推广大豆品种病害的初步调查

    Institute of Scientific and Technical Information of China (English)

    高翔; 陈晓兰; 潘汝谦; 严小龙; 廖红

    2012-01-01

    Diseases on new extensive soybean varieties in Guangdong Province were investigated and identified by general-and key-point investigations, and by traditional disease identification methods from June 2006 to October 2010. Twelve soybean diseases were recorded, including 9 fungal diseases, 1 bacterial disease, 1 nematode disease, and 1 viral disease. The fungal diseases were rust, downy mildew, red crown rot, Rhizoctonia foliar blight, an-thracnose, southern stem rot, powdery mildew, Fusarium root rot, and sooty mold, respectively. The bacterial disease was bacterial leaf spot. The nematode disease was root-knot nematode, and the viral disease was mosaic virus. The main diseases were rust, downy mildew, red crown rot, mosaic virus, Rhizoctonia foliar blight, and anthrac-nose. The occurrence of main diseases varied with seasons. In spring, soybean downy mildew was the most frequently occurring disease, whereas in summer, red crown rot, rust, Rhizoctonia foliar blight, and mosaic virus were more prevalent.%本文采用普查和定点调查以及传统的植物病害鉴定方法,在2006年6月至2010年10月对广东省新推广高产优质大豆品种的病害种类、发生危害及分布进行了调查.发现病害共有12种,其中真菌病害9种,分别是锈病、霜霉病、红冠腐病、丝核菌叶枯病、炭疽病、白绢病、白粉病、镰刀菌根腐病和煤烟病;细菌性病害、线虫病害和病毒病害各1种,分别为细菌性叶斑病、根结线虫病和花叶病.主要病害为锈病、霜霉病、红冠腐病、花叶病、丝核菌叶枯病和炭疽病等.不同季节大豆的主要病害发生情况不同.春大豆以霜霉病发生较为严重;而夏大豆则以红冠腐病、锈病、花叶病毒病和丝菌核叶枯病发生较严重.

  16. TiO2 photocatalytic antifungal technique for crops diseases control

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    TiO2 and l%Ce3+-TiO2 prepared by hydrothermal method were characterized by means of XRD and UV-visible diffusive reflectance spectra(DRS). The results of DRS analysis indicated that the 1%Ce3+-TiO2 catalyst had significant optical absorption in the visible region between 400-450 nm because electrons could be excited from the valence band of TiO2 or cerium oxides to Ce 4f level. To investigate the photocatalytic activity of different catalysts for crop fungal disease control, a series of Quine tests were carried out for cucumber powdery mildew and litchi downy blight control in home-made photocatalytic reactor. The results showed that TiO2photocatalysis technique should be effective to inhibit the growth of fungal diseases to some extent and P-25 had a higher activity for antifungal control than home-made TiO2 catalysts. TiO2-A prepared with Ti(SO4)2 is more active to contro 1 antifungal disease than TiO2-B prepared with TiOSO4 as precursor because the crystalline of TiO2-A was higher than that of TiO2-B. The antifungal index litchi downy blight control was greatly enhanced by doping 1% cerium ion. The antifungal index of 1.0%Ce3+-TiO2 was(47.0±4.7)%,(82.2 ± 3.5)%, (100± 0.0)% under indoor weaker light, solar light and black light, respectively. The results of field experiments showed that the antifungal index of 1.0%Ce3+-TiO2 was more than that of P-25. The antifungal index of 1.0%Ce3+-TiO2 was (81.7 ±6.5)%, (67.5 ±4.7)%, (38.6 ±1.9)% for litchi downy blight, maize southern leaf spot, and rice blast, respectively. It was concluded that TiO2 photocatalysis technique should be an effective way for litchi fungal disease control in practice.

  17. A deeper look at the response of oxygenated and non oxygenated VOC to mid-term drought over the seasonal cycle: the case study of a drought-resistant species

    Science.gov (United States)

    Saunier, Amelie; Ormeño Lafuente, Elena; Wortham, Henri; Temime-Roussel, Brice; Fernandez, Catherine

    2015-04-01

    At the end of this century, climatic models plan an intensification of summer drought in the Mediterranean area due to a 30% rain reduction and a temperature rise of 3.4 °C. Plants respond to drought by modifying their primary (growth) and their secondary metabolism, the later being partly represented by volatile organic compound (VOC) emissions, such as terpenes. With drought, oxygenated and non oxygenated terpene emissions have been observed to increase, decrease or remain unchanged according to drought severity and vegetal model. By contrast, the response of non-terpenic oxygenated compounds to drought has been poorly studied. The aim of this study is to determine the potential impact of a two-year drought period on the full screen of VOC released by Q. pubescens, with a focus on both isoprene and methanol, issued from plant anabolism , and the numerous highly volatile oxygenated VOC, issued from plant catabolism (i.e. issued from oxidation of isoprene or methanol). A 70 years-old Downy oak forest (Quercus pubescens), highly resistant to drought stress, was selected as model ecosystem since it is well widespread in Southern France occupying 321 000 ha. Downy oak also represents the major source of isoprene emissions in the Mediterranean area and, unlike the other major Quercus sp. of the region (i.e. Quercus ilex, a monoterpene emitter) the impact of watering withholding over years has never been tackled. The study was performed at the experimental platform of O3HP (Oak Observatory at Observatoire de Haute Provence) in Southern France which is equipped with both a rain exclusion (by 30 %) and a rain addition structure (simulating the rainiest years of the region), allowing for comparison with naturally watered trees. Using dynamic enclosure chambers at the branch level and PTR-MS-Q-ToF, we screened the anabolic VOC (isoprene, methanol) and the catabolic VOC (e.g. methacrolein, methyl vinyl ketone, C6 aldehydes and carboxylic acids) of trees located under the

  18. Phytoremediation of disturbed lands in Polar Regions of Russia

    Science.gov (United States)

    Shamsutdinova, Evgeniya

    2017-04-01

    In the Northern regions the problem of restoration of disturbed lands as a result of anthropogenic activities is particularly acut. A large role for the success of native plants to take hold and re-establish themselves is to allow the natural process to work without human intervention. However observation shows that low reserves of available moisture, poor soil nutrients, exposure to wind and water erosion make impossible of a complete restoration of lands due to natural revegetation. One of the methods used to minimize the effect of these factors is the phytoremediation. Research on the Pelyatinskom gas condensate field in the Taimyr Dolgano-Nenets municipal district revealed the efficacy of biological remediation of awnless brome, wildrye siberian, red fescue and kentucky bluegrass. Geobotanical studies of the tailings fields in Yakutia showed that for the phytoremediation of tailings of alluvial deposits of diamonds slough grass can be successfully used, and on the dumps of coal deposits with a high degree of survival of the willow, poplar, larch, alder stand and pine. Development of technology for remediation of placer gold deposits of the Komsomol mine and Bilibino in Chukotka has shown the effectiveness of sowing common oat, wildrye and larch. The study of the experience of recultivation on objects of the "Transneft-Baltic" in the North-Western Federal district allowed us to select as the recommended mixtures of species: meadow fescue, cocksfoot, timothy grass, white and alsike clover and alfalfa. The multicomponent mixture of red fescue, awnless brome, meadow fescue, timothy grass, couch grass, kentucky bluegrass, beckman's grass were successfully used at the mine of the Bovanenkovo oil and gas condensate field. On the technological grounds of the complex pumping station in the Yamalo-Nenets Autonomous area willows were planted. Pine and willow trees were planted on quarry workings in the Northern taiga of Western Siberia land .Planting of pines has shown

  19. Gender Analysis of Risk in Innovation System

    DEFF Research Database (Denmark)

    Ayinde, Ope; Muchie, Mammo; Abaniyan, E. O.

    2011-01-01

    This study analyzed risk by gender in innovation in Kwara state, Nigeria, using downy mildew resistant maize production as case study. The study employed primary and secondary data. The primary data were collected from well-structured questionnaires administered to both male and female producing...... the new maize variety. The analytical tools used include descriptive statistics, regression model; risk utility functions and risk parameter analysis. The result showed that invasion by animals, disease and pest, lack of access to credit wind and price fluctuation were the major risk facing the maize...... producers in the area in the usage of the new innovation. The study also revealed that male producers were willing to take risk in the new maize variety production than the female, while the females were more indifferent to the risk involved in the new maize production variety than males. None...

  20. Detection of a true breeding homeotic gene mutant Pps-1 with partially petaloid sepals in opium poppy (Papaver somniferum L.) and its genetic behavior.

    Science.gov (United States)

    Dhawan, Om Prakash; Dubey, Mukesh Kumar; Khanuja, Suman Preet Singh

    2007-01-01

    A spontaneous true breeding homeotic gene mutant Pps-1 with distinct partial petaloid sepals was detected in the population of downy mildew (DM)-resistant elite accession I-14 during our studies for the identification of disease resistance sources in opium poppy. The trait was found to be stable and inherited truly in the subsequent generations. Genetic studies were carried out through systematic reciprocal crosses with the parental wild-type genotype I-14, and segregation pattern of phenotypic characteristics in F(1) and F(2) populations clearly indicated single recessive nuclear gene control of the mutant character. The studies have demonstrated that the mutant phenotype is due to mutations at the Pps-1 locus that possibly corresponds to B-class function (according to ABC model) with negative control function. The mutant Pps-1 being single-whorl homeotic mutant might greatly help in providing insight into mechanisms of flower development in opium poppy.

  1. The conditions of forests in Italy. Results from the extensive surveys of Level I (1997-2010

    Directory of Open Access Journals (Sweden)

    Bussotti F

    2014-02-01

    Full Text Available The conditions of forests in Italy. Results from the extensive surveys of Level I (1997-2010. Monitoring of tree crown defoliation is carried out in Italy since the ’80, and in 1996 a comprehensive program of quality assurance has been implemented. Currently the monitoring network includes about 260 permanent plots and 7000 sample trees. The most representative tree species are: Fagus sylvatica (European beech, Quercus pubescens (downy oak, Quercus cerris (Turkey oak, Quercus ilex (holm oah, Castanea sativa (chestnut, Ostrya carpinifolia (hop hornbeam, Picea abies (spruce, Larix decidua (larch, Pinus nigra (black pine e Pinus sylvestris (Scots pine. These species represent the 80% of the whole sample, but only European beech is evenly distributed in Italy. The most important trends at national level concern the critical sanitary conditions of Castanea sativa and Quercus pubescens, as well as the high defoliation levels of Pinus sylvestris. The importance of this program in the context of climate change studies is discussed.

  2. New species of parasitic quill mites of the genus Picobia (Acari: Syringophilidae: Picobiinae) from North American birds.

    Science.gov (United States)

    Skoracki, Maciej; Hendricks, Sarah A; Spicer, Greg S

    2010-09-01

    Five new species of the genus Picobia are described and illustrated: (1) P. leucophaeus sp. nov. from the Laughing Gull Leucophaeus atricilla L. (Charadriiformes: Laridae) from Texas; (2) P. troglodytes sp. nov. from the House Wren Troglodytes aedon Vieillot (Passeriformes: Troglodytidae) from California; (3) P. cardinalis sp. nov. from the Northern Cardinal Cardinalis cardinalis (L.) (Passeriformes: Cardinalidae) from Texas; (4) P. carpodacus sp. nov. from the Purple Finch Carpodacus purpureus (Gmelin) (Passeriformes: Fringillidae) from California; and (5) P. psaltriparus sp. nov. from the Bushtit Psaltriparus minimus (Townsend) (Passeriformes: Aegithalidae) from Texas. Two avian species from the family Picidae (Piciformes) are recorded as new hosts for P. dryobatis (Fritsch, 1958): the Downy Woodpecker Picoides pubescens (L.) from Texas and the Ladder-backed Woodpecker Picoides scalaris (Wagler) from California. Additionally, all named species of the genus Picobia with their host associations and distributions are summarized in tabular form.

  3. Estimated 2nd Trimester Maternal Serum Markers AFP & HCG Moms for Down'S Syndrome Screening in Macao%第二妊娠期母血清甲胎球蛋白及人類絨毛膜促性腺激素篩選唐氏綜合症標記

    Institute of Scientific and Technical Information of China (English)

    王強; 梁敏慧; 林勇行

    2001-01-01

    目的進行第二妊娠期母血清甲胎球蛋白及人類絨毛膜促性腺激素篩選唐氏綜合症標記的測定.方法從1998年8月起,對澳門35歲以下,懷孕期在14至20孕週,單胎懷孕並且無明顯家族及染色體遺傳史的孕婦,通過産前診斷咨詢門診,利用電子計算機軟件程式,分別對孕婦的年齡、身高、體重、以及甲胎球蛋白及人類絨毛膜促性腺激素進行運算,得出有關的數值.所有數值如大於1/250者將被視爲陽性.其後,有關孕婦將被轉介作羊水檢驗以確診之.結果其中有三例羊水檢驗證實爲唐氏綜合症胎兒.該項檢驗的假陽性率爲1/17.但其中一例出現假陰性(高齡孕婦,同時接受了羊水檢驗並確診).該母血篩選檢查的準確性約60%.結論該項35歲以下,懷孕期在14至20週唐氏綜合症檢驗在澳門中國婦女人口中是可行的及可接受的.%Objective Offered second-trimester serum AFP and hCG screening study to pregnant women younger than 3 5 years should be offered maternal serum screening at 16 to 18 weeks of gestation and without other risk factors for chromosomal abnormalities. Materials Between August 1998 and January 2001, we Each woman was assigned a risk of having a Downis syndrome term pregnancy by using a computer software program that took into account her age, weight, AFP and hCG MoMs. All those with a risk of one in 250 or greater were designated screen-positive, subject to the revision of gestation by ultrasound examination. Results After revision of the gestation by ultrasound examination, 89 of them (97 per cent) accepted the offer of amniocentesis. Downis syndrome and all the women elected pregnancy termination affected two of these pregnancies. The odds of being affected, given a positive screening result, were one in 17. The screening programmed missed one Downis syndrome pregnancy. The detection rate was 60 per cent. Conclusion The study showed that second-trimester serum screening for

  4. Peptidoglycan from fermentation by-product triggers defense responses in grapevine.

    Directory of Open Access Journals (Sweden)

    Yang Chen

    Full Text Available Plants are constantly under attack from a variety of microorganisms, and rely on a series of complex detection and response systems to protect themselves from infection. Here, we found that a by-product of glutamate fermentation triggered defense responses in grapevine, increasing the expression of defense response genes in cultured cells, foliar chitinase activity, and resistance to infection by downy mildew in leaf explants. To identify the molecule that triggered this innate immunity, we fractionated and purified candidates extracted from Corynebacterium glutamicum, a bacterium used in the production of amino acids by fermentation. Using hydrolysis by lysozyme, a silkworm larva plasma detection system, and gel filtration analysis, we identified peptidoglycan as inducing the defense responses. Peptidoglycans of Escherichia coli, Bacillus subtilis, and Staphylococcus aureus also generated similar defensive responses.

  5. Compte rendu de la 18e Conférence Internationale sur le Tournesol : Mar del Plata & Balcarce (Argentine, 2012

    Directory of Open Access Journals (Sweden)

    Pilorgé Étienne

    2012-11-01

    Full Text Available The 18th International Sunflower Conference took place in Mar del Plata, Argentina, in February, 2012. The key-points and evolutions of sunflower research were presented, in the fields of agronomy, physiology, genetics and genomics, crop protection, quality and markets. Major evolutions can be observed concerning the sequencing of sunflower genome, announced to be complete by the end of 2012, but also concerning the use of models and the progress in the studies on the interactions between varieties genetic pattern, environment and crop management practices. In crop protection aspects, the evolutions of the major pathogens, downy mildew and Orobanche cumana, have been discussed, as well as the breeding efforts for genetic resistances, or the advances concerning the herbicides tolerant varieties. Evolutions in oil quality aspects have been exposed too, such as varieties enriched in stearic acid, or tocopherols, or with low contents in saturated fatty acids.

  6. 墨西哥香荚兰染色体及其变异的研究初报%A primary study on chromosome and its variation of Vanilla planifolia Andr.

    Institute of Scientific and Technical Information of China (English)

    陈小兰; 邓攀博; 杨明挚; 周恒苍; 陈善娜

    2004-01-01

    对栽培品种墨西哥香荚兰(Vanilla planifolia Andr.)进行了常规染色体分析,并对其杂交品种、无性繁殖植株(组培苗、扦插苗)和野生品种滇南香荚兰(V.siamensis Rolfe ex Downie)的染色体变异进行了观察比较.结果表明,香荚兰染色体的大小在0.2~2μm之间,为小染色体,2N=28,经长期继代培养的组培苗染色体出现变异的频率明显超过扦插苗和野生品种,微核、染色体桥和染色体断片的频率明显增高.

  7. Metabolic Fingerprint of PS3-Induced Resistance of Grapevine Leaves against Plasmopara viticola Revealed Differences in Elicitor-Triggered Defenses.

    Science.gov (United States)

    Adrian, Marielle; Lucio, Marianna; Roullier-Gall, Chloé; Héloir, Marie-Claire; Trouvelot, Sophie; Daire, Xavier; Kanawati, Basem; Lemaître-Guillier, Christelle; Poinssot, Benoît; Gougeon, Régis; Schmitt-Kopplin, Philippe

    2017-01-01

    Induction of plant resistance against pathogens by defense elicitors constitutes an attractive strategy to reduce the use of fungicides in crop protection. However, all elicitors do not systematically confer protection against pathogens. Elicitor-induced resistance (IR) thus merits to be further characterized in order to understand what makes an elicitor efficient. In this study, the oligosaccharidic defense elicitors H13 and PS3, respectively, ineffective and effective to trigger resistance of grapevine leaves against downy mildew, were used to compare their effect on the global leaf metabolism. Ultra high resolution mass spectrometry (FT-ICR-MS) analysis allowed us to obtain and compare the specific metabolic fingerprint induced by each elicitor and to characterize the associated metabolic pathways. Moreover, erythritol phosphate was identified as a putative marker of elicitor-IR.

  8. DINÂMICA DE INÓCULOS E DOENÇAS EM VIDEIRA SOB SISTEMA CONVENCIONAL E PROTEGIDO

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    DIÓGENES DA CRUZ BATISTA

    2015-01-01

    Full Text Available The effect of the covered and conventional cultivation of grapevine (cv. Superior Seedless on the aerial dispersion of pathogen inoculum and dynamic of diseases was investigated in two-year (2009 and 2010 and period similar to the year. The experiment was conducted at the experimental station of Embrapa semiarid. The traps were maintained at 0.5 meters above the canopy of the grapevine, and the samples taken every 24 hours with the exchange of slides 9:00 a.m. Greater dispersion of pathogens (Plasmopara viticola, Phakopsora euvitis, Alternaria alternata and intensity of diseases (downy mildew, rust, and bacterial canker were detected in grapevines under conventional cultivation. The aerial dispersal of the fungus Lasiodiplodia theobromae was similar under grapevine covered and uncovered.

  9. Deletion of Salmonella enterica serovar typhimurium sipC gene

    Institute of Scientific and Technical Information of China (English)

    Maryam; Safarpour; Dehkordi; Abbas; Doosti; Asghar; Arshi

    2015-01-01

    Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene and kanamycin gene were PCR amplified.Each of these DNA fragment was cloned into p GEM T-easy vector.The construct was confirmed by PCR and restriction digest.Results:PCR amplified 320,206 and 835 bp DNA fragments were subcloned into p ET-32 vector resulting with a plasmid called p ET-32-sip C up-kan-sip C down.Conclusions:The new plasmid(p ET-32-sip C up-kan-sip C down)is useful for genetic engineering and for future manipulation of S.typhimurium sip C gene.

  10. Approaches in breeding for high quality protein maize

    Directory of Open Access Journals (Sweden)

    Denić Miloje

    2008-01-01

    Full Text Available Maize is the principal crop and major staple food in the most African and South American countries. The main problem in human nutrition in developing countries, and in livestock feed in developed countries, is insufficient production and poor quality of cereal proteins. In the case of maize, due to the very low content of essential amino acids lysine and tryptophan in grain endosperm, biological value is very low, which is main limiting factor of common maize in human nutrition and feeding of monogastric animals. Quality protein maize (QPM can help in solving of this problem. Maize production also faces serious constraints caused by agro-ecological conditions and poor socio-economic situation. To alleviate the effect of the constraints, selected genotypes with more desirable traits and appropriate field-plot techniques to create multiple-stress conditions, were used. It was found that, in downy mildew nursery distance up to 35 m from spreader plot is providing sufficient down load of spores for plant infection, provided that the testing breeding materials are planted towards to down-stream direction of the dominant wind. Using these breeding approaches large number of early, white and flint synthetics, composites and inbred lines were created with resistance or tolerance to downy mildew (DMR, maize streak virus (SR and drought (DT. Created genotypes exhibited very good kernel modification and yield potential under low and normal inputs. In the case of synthetics and composites, besides tolerance to multiple stress factors, they were competing in yield with local QPM and normal maize checks. In the case of created inbred lines high combining ability was exhibited both in non-conventional and conventional maize hybrids. Trial data revealed that in the most cases the best entries were over-yielding the best checks.

  11. Transcriptomic analysis of the interaction between Helianthus annuus and its obligate parasite Plasmopara halstedii shows single nucleotide polymorphisms in CRN sequences

    Directory of Open Access Journals (Sweden)

    Gouzy Jérôme

    2011-10-01

    Full Text Available Abstract Background Downy mildew in sunflowers (Helianthus annuus L. is caused by the oomycete Plasmopara halstedii (Farl. Berlese et de Toni. Despite efforts by the international community to breed mildew-resistant varieties, downy mildew remains a major threat to the sunflower crop. Very few genomic, genetic and molecular resources are currently available to study this pathogen. Using a 454 sequencing method, expressed sequence tags (EST during the interaction between H. annuus and P. halstedii have been generated and a search was performed for sites in putative effectors to show polymorphisms between the different races of P. halstedii. Results A 454 pyrosequencing run of two infected sunflower samples (inbred lines XRQ and PSC8 infected with race 710 of P. halstedii, which exhibit incompatible and compatible interactions, respectively generated 113,720 and 172,107 useable reads. From these reads, 44,948 contigs and singletons have been produced. A bioinformatic portal, HP, was specifically created for in-depth analysis of these clusters. Using in silico filtering, 405 clusters were defined as being specific to oomycetes, and 172 were defined as non-specific oomycete clusters. A subset of these two categories was checked using PCR amplification, and 86% of the tested clusters were validated. Twenty putative RXLR and CRN effectors were detected using PSI-BLAST. Using corresponding sequences from four races (100, 304, 703 and 710, 22 SNPs were detected, providing new information on pathogen polymorphisms. Conclusions This study identified a large number of genes that are expressed during H. annuus/P. halstedii compatible or incompatible interactions. It also reveals, for the first time, that an infection mechanism exists in P. halstedii similar to that in other oomycetes associated with the presence of putative RXLR and CRN effectors. SNPs discovered in CRN effector sequences were used to determine the genetic distances between the four races

  12. Identification of host fruit volatiles from domestic apple (Malus domestica), native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (C. monogyna) attractive to Rhagoletis pomonella flies from the western United States.

    Science.gov (United States)

    Cha, Dong H; Yee, Wee L; Goughnour, Robert B; Sim, Sheina B; Powell, Thomas H Q; Feder, Jeffrey L; Linn, Charles E

    2012-03-01

    The apple maggot fly, Rhagoletis pomonella, infests apple (Malus domestica) and hawthorn species (most notably the downy hawthorn, Crataegus mollis) in the eastern USA. Evidence suggests that the fly was introduced into the western USA sometime in the last 60 years. In addition to apple, R. pomonella also infests two species of hawthorns in the western USA as major hosts: the native black hawthorn (C. douglasii) and the introduced ornamental English hawthorn, C. monogyna. Apple and downy hawthorn-origin flies in the eastern USA use volatile blends emitted from the surface of their respective ripening fruit to find and discriminate among host trees. To test whether the same is true for western flies, we used coupled gas chromatography and electroantennographic detection (GC-EAD) and developed a 7-component apple fruit blend for western apple-origin flies, an 8-component black hawthorn fruit blend for flies infesting C. douglasii, and a 9-component ornamental hawthorn blend for flies from C. monogyna. Crataegus douglasii and C. monogyna-origin flies showed similar levels of upwind directed flight to their respective natal synthetic fruit blends in flight tunnel assays compared to whole fruit adsorbent extracts, indicating that the blends contain all the behaviorally relevant fruit volatiles to induce maximal response levels. The black and ornamental hawthorn blends shared four compounds in common including 3-methylbutan-1-ol, which appears to be a key volatile for R. pomonella populations in the eastern, southern, and western USA that show a preference for fruit from different Crataegus species. However, the blends also differed from one another and from domesticated apple in several respects that make it possible that western R. pomonella flies behaviorally discriminate among fruit volatiles and form ecologically differentiated host races, as is the case for eastern apple and hawthorn flies.

  13. Biological Mode of Action of Dimethomorph on Pseudoperonospora cubensis and Its Systemic Activity in Cucumber

    Institute of Scientific and Technical Information of China (English)

    WANG Han-cheng; ZHOU Ming-guo; WANG Jian-xin; CHEN Chang-jun; LI Hong-xia; SUN Hai-yan

    2009-01-01

    Dimethomorph is a fungicide with high activity against Peronosporomycetes plant pathogens. The present study showed that dimethomorph is effective on controlling the oomycete fungal pathogen Pseudoperonospora cubensis causing downy mildew on cucumber. The fungicide did not affect zoospores discharge from sporangia of P. cubensis, but it strongly inhibited mycelial growth and sporangial production in vitro and increased lysis of zoospores. Dose of 2 mg L-1 of dimethomorph was sufficient to inhibit mycelial growth and sporangial production of P. cubensis on leaf disks, 5 mg L-1 was enough to lyse zoospores of P. cubensis, and 25 mg L-1 was required to inhibit sporangial production on detached leaves. In whole plant tests, dimethomorph exhibited strong protective and curative activity. Dimethomorph when applied at a dose of 300 mg L-1 for 1, 3, 5, 7 days before inoculation exhibited 100% efficacy on disease control. Onthe other hand, efficacies of 67.1 and 31.5% were obtained when the same dose of dimethomorph was applied for 1 and 3 days after inoculation, respectively. So dimethomorph had persistence effect on leaves for 7 days at least and exhibited strong protective and curative activity. Bioassay analyses showed that dimethomorph could be translocated in the xylem system, redistributed in the leaf, and penetrated from the upper surface to the lower surface of the leaf but could not be translocated in phloem system or transferred from the roots to leaves of cucumber plants in sufficient amounts for disease control. The biocharacteristics of dimethomorph make it well suitable for integration of a control programme against downy mildew disease on cucumber and as a component to delay other peronosporomycetes fungicide-resistance development.

  14. Impact of Climate Change on Five Major Crop Fungal Diseases: Building Climatic Indicators of Infection Risk

    Science.gov (United States)

    Launay, M.; Caubel, J.; Bourgeois, G.; Huard, F.; Garcia de Cortazar-Atauri, I.

    2013-12-01

    The climate change will modify the severity and occurrence of fungal crop diseases, as the bioclimatic niches of pathogens will shift according to temperature and rainfall patterns evolution. Therefore it becomes necessary to integrate fungal disease pressure assessment into evaluation tools of crop suitability at the regional level. The aim of this study was to build two climatic indicators, the Average Infection Efficiency (AIE) and the Number of Infection Days (NID), quantifying the potential effect of climate on infection intensity and occurrence. A simple and continuous function was developed to calculate them, which is easy to parameterize from experimental measurements, usable on large spatial scales and adaptable to various pathogens. The evolution of those climatic indicators was then studied for five major fungal crop diseases in Northern France, the phoma of oilseed rape, the potato late blight, the downy mildew of grape, the leaf rust of wheat and the net blotch of barley. These indicators were applied on a multisite analysis in Northern France. They were calculated during the crop cycle when the host plant is able to be infected, over the period between 1970 and 2100 for the balanced scenario of climate change A1B. In late spring and summer, higher temperatures combined with lower humidity reduced the risk of infection of potato late blight and downy mildew of grape. In autumn and spring the balance between warmer temperatures and lower humidity determined the risk of infection on oilseed rape and cereals: increased risk in late autumn and early spring, and decreased risk in early autumn and mid-spring when low humidity becomes limiting. This statement highlighted the need for using between year scale for a relevant analysis of climate change impact on infection risk. The indicators we developed are thus useful for land management at regional scale and medium term, in particular for stakeholders who need decision support tools through which they could

  15. Protein kinase C is likely to be involved in zoosporogenesis and maintenance of flagellar motility in the peronosporomycete zoospores.

    Science.gov (United States)

    Islam, Md Tofazzal; von Tiedemann, Andreas; Laatsch, Hartmut

    2011-08-01

    The motility of zoospores is critical in the disease cycles of Peronosporomycetes that cause devastating diseases in plants, fishes, vertebrates, and microbes. In the course of screening for secondary metabolites, we found that ethyl acetate extracts of a marine Streptomyces sp. strain B5136 rapidly impaired the motility of zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 0.1 μg/ml. The active principle in the extracts was identified as staurosporine, a known broad-spectrum inhibitor of protein kinases, including protein kinase C (PKC). In the presence of staurosporine (2 nM), zoospores moved very slowly in their axis or spun in tight circles, instead of displaying straight swimming in a helical fashion. Compounds such as K-252a, K-252b, and K-252c structurally related to staurosporine also impaired the motility of zoospores in a similar manner but at varying doses. Among the 22 known kinase inhibitors tested, the PKC inhibitor chelerythrine was the most potent to arrest the motility of zoospores at concentrations starting from 5 nM. Inhibitors that targeted kinase pathways other than PKC pathways did not practically show any activity in impairing zoospore motility. Interestingly, both staurosporine (5 nM) and chelerythrine (10 nM) also inhibited the release of zoospores from the P. viticola sporangia in a dose-dependent manner. In addition, staurosporine completely suppressed downy mildew disease in grapevine leaves at 2 μM, suggesting the potential of small-molecule PKC inhibitors for the control of peronosporomycete phytopathogens. Taken together, these results suggest that PKC is likely to be a key signaling mediator associated with zoosporogenesis and the maintenance of flagellar motility in peronosporomycete zoospores.

  16. Interspecific variation in resistance of Asian, European, and North American birches (Betula spp.) to bronze birch borer (Coleoptera: Buprestidae).

    Science.gov (United States)

    Nielsen, David G; Muilenburg, Vanessa L; Herms, Daniel A

    2011-06-01

    Bronze birch borer (Agrilus anxius Gory) is the key pest of birches (Betula spp.) in North America, several of which have been recommended for ornamental landscapes based on anecdotal reports of borer resistance that had not been confirmed experimentally. In a 20-yr common garden experiment initiated in 1979 in Ohio, North American birch species, including paper birch (Betula papyrifera Marshall), 'Whitespire' gray birch (Betula populifolia Marshall), and river birch (Betula nigra L.), were much more resistant to bronze birch borer than species indigenous to Europe and Asia, including European white birch (Betula pendula Roth), downy birch (Betula pubescens Ehrh.), monarch birch (Betula maximowicziana Regel), and Szechuan white birch (Betula szechuanica Jansson). Within 8 yr of planting, every European white, downy, and Szechuan birch had been colonized and killed, although 100% of monarch birch had been colonized and 88% of these plants were killed after nine years. Conversely, 97% of river birch, 76% of paper birch, and 73% Whitespire gray birch were alive 20 yr after planting, and river birch showed no evidence of colonization. This pattern is consistent with biogeographic theory of plant defense: North American birch species that share a coevolutionary history with bronze birch borer were much more resistant than naïve hosts endemic to Europe and Asia, possibly by virtue of evolution of targeted defenses. This information suggests that if bronze birch borer were introduced to Europe or Asia, it could threaten its hosts there on a continental scale. This study also exposed limitations of anecdotal observation as evidence of host plant resistance.

  17. Molecular Characterization and Diagnosis of QoI Resistance in Cucumber and Eggplant Fungal Pathogens.

    Science.gov (United States)

    Ishii, H; Yano, K; Date, H; Furuta, A; Sagehashi, Y; Yamaguchi, T; Sugiyama, T; Nishimura, K; Hasama, W

    2007-11-01

    ABSTRACT The molecular mechanism of QoI fungicide resistance was studied using isolates of cucumber Corynespora leaf spot fungus (Corynespora cassiicola) and the eggplant leaf mold (Mycovellosiella nattrassii). In both pathogens, a mutation at position 143 from glycine to alanine (G143A) was detected in the cytochrome b gene that encodes for the fungicide-targeted protein. Moreover, the nucleotide sequence at amino acid position 143 was converted from GGT or GGA in sensitive (wild-type) to GCT or GCA in resistant (mutant-type) isolates. The methods of polymerase chain reaction restriction fragment length polymorphism commonly used for QoI resistance monitoring were employed successfully, leading to the amplified gene fragment from resistant isolates being cut with the restriction enzyme ItaI. However, heteroplasmy (the coexistence of wild-type and mutated alleles) was found when the resistant isolates of C. cassiicola, M. nattrassii, and Colletotrichum gloeosporioides (strawberry anthracnose fungus) were subcultured in the presence or absence of QoI fungicides. QoI resistance of cucumber powdery and downy mildew isolates persisted for a few years following the removal of the selection pressure imposed by the fungicide under both laboratory and commercial greenhouse conditions. The proportion of mutated sequences in cytochrome b gene decreased over time in the pathogen population. The protective efficacy of the full dose of azoxystrobin decreased when the populations of powdery and downy mildews contained resistant isolates at 10%. Using FMBIO, a fluorescence bio-imaging analyzer, the mutant allele from the QoI-resistant isolates could be detected at the level of 1%, whereas the detection sensitivity of ethidium-bromide-stained gels was approximately 10 times lower.

  18. Genetic analysis of a host determination mechanism of bromoviruses in Arabidopsis thaliana.

    Science.gov (United States)

    Fujisaki, Koki; Iwahashi, Fukumatsu; Kaido, Masanori; Okuno, Tetsuro; Mise, Kazuyuki

    2009-03-01

    Brome mosaic virus (BMV) and Spring beauty latent virus (SBLV) are closely related, tripartite RNA plant viruses. In Arabidopsis thaliana, BMV shows limited multiplication whereas SBLV efficiently multiplies. Such distinct multiplication abilities have been observed commonly in all Arabidopsis accessions tested. We used this model system to analyze the molecular mechanism of viral resistance in plants at the species level. Unlike SBLV, BMV multiplication was limited even in protoplasts and a reassortment assay indicated that at least viral RNA1 and/or RNA2 determine such distinct infectivities. By screening Arabidopsis mutants with altered defense responses, we found that BMV multiplies efficiently in cpr5-2 mutant plants. This mutation specifically enhanced BMV multiplication in protoplasts, which depended on the functions of RNA1 and RNA2. In the experiment using DNA vectors to express BMV replication proteins encoded by RNA1 and RNA2, BMV RNA3 accumulation in cpr5-2 protoplasts was similar to that in wild-type Col-0 protoplasts, despite significant reduction of accumulation levels of replication proteins, suggesting that cpr5-2 mutation could enhance BMV multiplication independently of increased accumulation, therefore enhanced translation and stabilization, of the replication proteins.

  19. Overexpression and self-assembly of virus-like particles in Nicotiana benthamiana by a single-vector DNA replicon system.

    Science.gov (United States)

    Moon, Ki-Beom; Lee, Jisu; Kang, Sebyung; Kim, Moonil; Mason, Hugh S; Jeon, Jae-Heung; Kim, Hyun-Soon

    2014-10-01

    Based on recent developments, virus-like particles (VLPs) are considered to be perfect candidates as nanoplatforms for applications in materials science and medicine. To succeed, mass production of VLPs and self-assembly into a correct form in plant systems are key factors. Here, we report expression of synthesized coat proteins of the three viruses, Brome mosaic virus, Cucumber mosaic virus, and Maize rayado fino virus, in Nicotiana benthamiana and production of self-assembled VLPs by transient expression system using agroinfiltration. Each coat protein was synthesized and cloned into a pBYR2fp single replicon vector. Target protein expression in cells containing p19 was fourfold higher than that of cells lacking p19. After agroinfiltration, protein expression was analyzed by SDS-PAGE and quantitative image analyzer. Quantitative analysis showed that BMVCP, CMVCP, and MRFVCP concentrations were 0.5, 1.0, and 0.8 mg · g(-1) leaf fresh weight, respectively. VLPs were purified by sucrose cushion ultracentrifugation and then analyzed by transmission electron microscopy. Our results suggested that BMVCP and CMVCP proteins expressed in N. benthamiana leaves were able to correctly self-assemble into particles. Moreover, we evaluated internal cavity accessibility of VLPs to load foreign molecules. Finally, plant growth conditions after agroinfiltration are critical for increasing heterologous protein expression levels in a transient expression system.

  20. In Search of the English Sabbat: Popular Conceptions of Witches’ Meetings in Early Modern England

    Directory of Open Access Journals (Sweden)

    James Sharpe

    2013-03-01

    Full Text Available This article explores the evidence for belief in the witches’ sabbat in early modern England. England is generally thought of as a country where the concept of the sabbat did not exist, and it was certainly largely absent from elite thinking on witchcraft, as displayed in the witchcraft statutes of 1563 and 1604 and Elizabethan and Jacobean demonological writings. But evidence entering the historical record mainly via deposi- tions taken by justices of the peace suggests that there was a widespread popular belief in the sabbat or in parallel forms of witches’ meetings, evidence that the concept of the sabbat existed in popular culture. In this, the English evidence seems to support Carlo Ginzburg’s model of the sabbat being essentially a popular construction in its origins. The article also examines a play based on one of the historical incidents analysed, Richard Brome and Thomas Heywood’s The Late Lancashire Witches (1634, and uses it as a starting point for a brief discussion of witchcraft motifs in contemporary drama, notably Shakespeare’s Macbeth.

  1. Virus-resembling nano-structures for near infrared fluorescence imaging of ovarian cancer HER2 receptors

    Science.gov (United States)

    Guerrero, Yadir A.; Bahmani, Baharak; Singh, Sheela P.; Vullev, Valentine I.; Kundra, Vikas; Anvari, Bahman

    2015-10-01

    Ovarian cancer remains the dominant cause of death due to malignancies of the female reproductive system. The capability to identify and remove all tumors during intraoperative procedures may ultimately reduce cancer recurrence, and lead to increased patient survival. The objective of this study is to investigate the effectiveness of an optical nano-structured system for targeted near infrared (NIR) imaging of ovarian cancer cells that over-express the human epidermal growth factor receptor 2 (HER2), an important biomarker associated with ovarian cancer. The nano-structured system is comprised of genome-depleted plant-infecting brome mosaic virus doped with NIR chromophore, indocyanine green, and functionalized at the surface by covalent attachment of monoclonal antibodies against the HER2 receptor. We use absorption and fluorescence spectroscopy, and dynamic light scattering to characterize the physical properties of the constructs. Using fluorescence imaging and flow cytometry, we demonstrate the effectiveness of these nano-structures for targeted NIR imaging of HER2 receptors in vitro. These functionalized nano-materials may provide a platform for NIR imaging of ovarian cancer.

  2. Targeted imaging of ovarian cancer cells using viral nanoparticles doped with indocyanine green

    Science.gov (United States)

    Guerrero, Yadir; Bahmani, Baharak; Jung, Bonsu; Vullev, Valentine; Kundra, Vikas; Anvari, Bahman

    2013-03-01

    Our group has constructed a new type of viral nanoparticles (VNPs) from genome-depleted plant infecting brome mosaic virus (BMV) that encapsulates the FDA-approved near infrared (NIR) indocyanine green (ICG)[1]. We refer to these VNPs as optical viral ghosts (OVGs) since the constructs lack the genomic content of wild-type BMV. One of our areas of interest is the application of OVGs for real-time intraoperative NIR fluorescence imaging of small peritoneal ovarian tumor nodules. We target human epidermal growth factor receptor-2 (HER-2) expression in ovarian cancer as a biomarker associated with ovarian cancer, since its over-expression is linked to the disease's progression to death. We functionalize the OVGs with anti-HER-2 monoclonal antibodies using reductive amination methods. We used fluorescence imaging to visualize the SKOV-3 cells (high HER-2 expression) after incubation with free ICG, OVGs, and functionalized OVGs. Our results suggest the possibility of using anti-HER2 conjugated OVGs in conjunction with cytoreductive surgery to detect small tumor nodules (<5cm) which currently are not excised during surgery.

  3. Evolutionary Relationships between Rhynchosporium lolii sp. nov. and Other Rhynchosporium Species on Grasses

    Science.gov (United States)

    King, Kevin M.; West, Jonathan S.; Brunner, Patrick C.; Dyer, Paul S.; Fitt, Bruce D. L.

    2013-01-01

    The fungal genus Rhynchosporium (causative agent of leaf blotch) contains several host-specialised species, including R. commune (colonising barley and brome-grass), R. agropyri (couch-grass), R. secalis (rye and triticale) and the more distantly related R. orthosporum (cocksfoot). This study used molecular fingerprinting, multilocus DNA sequence data, conidial morphology, host range tests and scanning electron microscopy to investigate the relationship between Rhynchosporium species on ryegrasses, both economically important forage grasses and common wild grasses in many cereal growing areas, and other plant species. Two different types of Rhynchosporium were found on ryegrasses in the UK. Firstly, there were isolates of R. commune that were pathogenic to both barley and Italian ryegrass. Secondly, there were isolates of a new species, here named R. lolii, that were pathogenic only to ryegrass species. R. lolii was most closely related to R. orthosporum, but exhibited clear molecular, morphological and host range differences. The species was estimated to have diverged from R. orthosporum ca. 5735 years before the present. The colonisation strategy of all of the different Rhynchosporium species involved extensive hyphal growth in the sub-cuticular regions of the leaves. Finally, new species-specific PCR diagnostic tests were developed that could distinguish between these five closely related Rhynchosporium species. PMID:24146740

  4. Syngas Production from Pyrolysis of Nine Composts Obtained from Nonhybrid and Hybrid Perennial Grasses

    Science.gov (United States)

    Hlavsová, Adéla; Raclavská, Helena; Juchelková, Dagmar; Škrobánková, Hana; Frydrych, Jan

    2014-01-01

    A pyrolysis of compost for the production of syngas with an explicit H2/CO = 2 or H2/CO = 3 was investigated in this study. The composts were obtained from nonhybrid (perennial) grasses (NHG) and hybrid (perennial) grasses (HG). Discrepancies in H2 evolution profiles were found between NHG and HG composts. In addition, positive correlations for NHG composts were obtained between (i) H2 yield and lignin content, (ii) H2 yield and potassium content, and (iii) CO yield and cellulose content. All composts resulted in H2/CO = 2 and five of the nine composts resulted in H2/CO = 3. Exceptionally large higher heating values (HHVs) of pyrolysis gas, very close to HHVs of feedstock, were obtained for composts made from mountain brome (MB, 16.23 MJ/kg), hybrid Becva (FB, 16.45 MJ/kg), and tall fescue (TF, 17.43 MJ/kg). The MB and FB composts resulted in the highest syngas formation with H2/CO = 2, whereas TF compost resulted in the highest syngas formation with H2/CO = 3. PMID:25101320

  5. Evolutionary relationships between Rhynchosporium lolii sp. nov. and other Rhynchosporium species on grasses.

    Directory of Open Access Journals (Sweden)

    Kevin M King

    Full Text Available The fungal genus Rhynchosporium (causative agent of leaf blotch contains several host-specialised species, including R. commune (colonising barley and brome-grass, R. agropyri (couch-grass, R. secalis (rye and triticale and the more distantly related R. orthosporum (cocksfoot. This study used molecular fingerprinting, multilocus DNA sequence data, conidial morphology, host range tests and scanning electron microscopy to investigate the relationship between Rhynchosporium species on ryegrasses, both economically important forage grasses and common wild grasses in many cereal growing areas, and other plant species. Two different types of Rhynchosporium were found on ryegrasses in the UK. Firstly, there were isolates of R. commune that were pathogenic to both barley and Italian ryegrass. Secondly, there were isolates of a new species, here named R. lolii, that were pathogenic only to ryegrass species. R. lolii was most closely related to R. orthosporum, but exhibited clear molecular, morphological and host range differences. The species was estimated to have diverged from R. orthosporum ca. 5735 years before the present. The colonisation strategy of all of the different Rhynchosporium species involved extensive hyphal growth in the sub-cuticular regions of the leaves. Finally, new species-specific PCR diagnostic tests were developed that could distinguish between these five closely related Rhynchosporium species.

  6. A universal BMV-based RNA recombination system--how to search for general rules in RNA recombination.

    Science.gov (United States)

    Alejska, Magdalena; Figlerowicz, Magdalena; Malinowska, Nelli; Urbanowicz, Anna; Figlerowicz, Marek

    2005-07-07

    At present, there is no doubt that RNA recombination is one of the major factors responsible for the generation of new RNA viruses and retroviruses. Numerous experimental systems have been created to investigate this complex phenomenon. Consequently, specific RNA structural motifs mediating recombination have been identified in several viruses. Unfortunately, up till now a unified model of genetic RNA recombination has not been formulated, mainly due to difficulties with the direct comparison of data obtained for different RNA-based viruses. To solve this problem, we have attempted to construct a universal system in which the recombination activity of various RNA sequences could be tested. To this end, we have used brome mosaic virus, a model (+)RNA virus of plants, for which the structural requirements of RNA recombination are well defined. The effectiveness of the new homomolecular system has been proven in an experiment involving two RNA sequences derived from the hepatitis C virus genome. In addition, comparison of the data obtained with the homomolecular system with those generated earlier using the heteromolecular one has provided new evidence that the mechanisms of homologous and non-homologous recombination are different and depend on the virus' mode of replication.

  7. Molecular studies on bromovirus capsid protein. VII. Selective packaging on BMV RNA4 by specific N-terminal arginine residuals.

    Science.gov (United States)

    Choi, Y G; Rao, A L

    2000-09-15

    An arginine-rich RNA-binding motif (ARM) found at the N-proximal region of Brome mosaic virus (BMV) coat protein (CP) adopts alpha-helical conformation and shares homology with CPs of plant and insect RNA viruses, HIV-Rev and Tat proteins, bacterial antiterminators, and ribosomal splicing factors. The ARM of BMV CP, consisting of amino acids 9 through 21 with six arginine residues, is essential for RNA binding and subsequent packaging. In this study analysis of the alpha-helical contents of wild-type and mutant peptides by circular dichroism spectra identified protein determinants required for such conformation. Electrophoretic mobility-shift assays between viral RNA and BMV CP peptides with either proline or alanine substitutions revealed that the interaction is nonspecific. Expression in vivo of mature full-length BMV CP subunits, having the same substitutions for each arginine within the ARM, derived from biologically active clones was found to be competent to assemble into infectious virions and cause visible symptom phenotypes in whole plants. However, analysis of virion progeny RNA profiles of CP variants and subsequent in vitro reassembly assays between mutant CP and four BMV RNAs unveiled the ability of arginine residues at positions 10, 13, or 14 of the ARM to confer selective packaging of BMV RNA4. Thus, BMV CP contains determinants that specifically interact with RNA4 to ensure selective packaging.

  8. Host ESCRT proteins are required for bromovirus RNA replication compartment assembly and function.

    Directory of Open Access Journals (Sweden)

    Arturo Diaz

    2015-03-01

    Full Text Available Positive-strand RNA viruses genome replication invariably is associated with vesicles or other rearranged cellular membranes. Brome mosaic virus (BMV RNA replication occurs on perinuclear endoplasmic reticulum (ER membranes in ~70 nm vesicular invaginations (spherules. BMV RNA replication vesicles show multiple parallels with membrane-enveloped, budding retrovirus virions, whose envelopment and release depend on the host ESCRT (endosomal sorting complexes required for transport membrane-remodeling machinery. We now find that deleting components of the ESCRT pathway results in at least two distinct BMV phenotypes. One group of genes regulate RNA replication and the frequency of viral replication complex formation, but had no effect on spherule size, while a second group of genes regulate RNA replication in a way or ways independent of spherule formation. In particular, deleting SNF7 inhibits BMV RNA replication > 25-fold and abolishes detectable BMV spherule formation, even though the BMV RNA replication proteins accumulate and localize normally on perinuclear ER membranes. Moreover, BMV ESCRT recruitment and spherule assembly depend on different sets of protein-protein interactions from those used by multivesicular body vesicles, HIV-1 virion budding, or tomato bushy stunt virus (TBSV spherule formation. These and other data demonstrate that BMV requires cellular ESCRT components for proper formation and function of its vesicular RNA replication compartments. The results highlight growing but diverse interactions of ESCRT factors with many viruses and viral processes, and potential value of the ESCRT pathway as a target for broad-spectrum antiviral resistance.

  9. The Lsm1-7-Pat1 complex promotes viral RNA translation and replication by differential mechanisms.

    Science.gov (United States)

    Jungfleisch, Jennifer; Chowdhury, Ashis; Alves-Rodrigues, Isabel; Tharun, Sundaresan; Díez, Juana

    2015-08-01

    The Lsm1-7-Pat1 complex binds to the 3' end of cellular mRNAs and promotes 3' end protection and 5'-3' decay. Interestingly, this complex also specifically binds to cis-acting regulatory sequences of viral positive-strand RNA genomes promoting their translation and subsequent recruitment from translation to replication. Yet, how the Lsm1-7-Pat1 complex regulates these two processes remains elusive. Here, we show that Lsm1-7-Pat1 complex acts differentially in these processes. By using a collection of well-characterized lsm1 mutant alleles and a system that allows the replication of Brome mosaic virus (BMV) in yeast we show that the Lsm1-7-Pat1 complex integrity is essential for both, translation and recruitment. However, the intrinsic RNA-binding ability of the complex is only required for translation. Consistent with an RNA-binding-independent function of the Lsm1-7-Pat1 complex on BMV RNA recruitment, we show that the BMV 1a protein, the sole viral protein required for recruitment, interacts with this complex in an RNA-independent manner. Together, these results support a model wherein Lsm1-7-Pat1 complex binds consecutively to BMV RNA regulatory sequences and the 1a protein to promote viral RNA translation and later recruitment out of the host translation machinery to the viral replication complexes.

  10. Host ESCRT proteins are required for bromovirus RNA replication compartment assembly and function.

    Science.gov (United States)

    Diaz, Arturo; Zhang, Jiantao; Ollwerther, Abigail; Wang, Xiaofeng; Ahlquist, Paul

    2015-03-01

    Positive-strand RNA viruses genome replication invariably is associated with vesicles or other rearranged cellular membranes. Brome mosaic virus (BMV) RNA replication occurs on perinuclear endoplasmic reticulum (ER) membranes in ~70 nm vesicular invaginations (spherules). BMV RNA replication vesicles show multiple parallels with membrane-enveloped, budding retrovirus virions, whose envelopment and release depend on the host ESCRT (endosomal sorting complexes required for transport) membrane-remodeling machinery. We now find that deleting components of the ESCRT pathway results in at least two distinct BMV phenotypes. One group of genes regulate RNA replication and the frequency of viral replication complex formation, but had no effect on spherule size, while a second group of genes regulate RNA replication in a way or ways independent of spherule formation. In particular, deleting SNF7 inhibits BMV RNA replication > 25-fold and abolishes detectable BMV spherule formation, even though the BMV RNA replication proteins accumulate and localize normally on perinuclear ER membranes. Moreover, BMV ESCRT recruitment and spherule assembly depend on different sets of protein-protein interactions from those used by multivesicular body vesicles, HIV-1 virion budding, or tomato bushy stunt virus (TBSV) spherule formation. These and other data demonstrate that BMV requires cellular ESCRT components for proper formation and function of its vesicular RNA replication compartments. The results highlight growing but diverse interactions of ESCRT factors with many viruses and viral processes, and potential value of the ESCRT pathway as a target for broad-spectrum antiviral resistance.

  11. Systemic virus-induced gene silencing allows functional characterization of maize genes during biotrophic interaction with Ustilago maydis.

    Science.gov (United States)

    van der Linde, Karina; Kastner, Christine; Kumlehn, Jochen; Kahmann, Regine; Doehlemann, Gunther

    2011-01-01

    Infection of maize (Zea mays) plants with the corn smut fungus Ustilago maydis leads to the formation of large tumors on the stem, leaves and inflorescences. In this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed massive and stage-specific changes in host gene expression during disease progression. To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a virus-induced gene silencing (VIGS) system based on the brome mosaic virus (BMV) for maize. Conditions were established that allowed successful U. maydis infection of BMV-preinfected maize plants. This set-up enabled quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (qRT-PCR)-based readout. In proof-of-principle experiments, an U. maydis-induced terpene synthase was shown to negatively regulate disease development while a protein involved in cell death inhibition was required for full virulence of U. maydis. The results suggest that this system is a versatile tool for the rapid identification of maize genes that determine compatibility with U. maydis.

  12. Seasonal infestations of two stem borers (Lepidoptera: Crambidae) in noncrop grasses of Gulf Coast rice agroecosystems.

    Science.gov (United States)

    Beuzelin, J M; Mészáros, A; Reagan, T E; Wilson, L T; Way, M O; Blouin, D C; Showler, A T

    2011-10-01

    Infestations of two stem borers, Eoreuma loftini (Dyar) and Diatraea saccharalis (F.) (Lepidoptera: Crambidae), were compared in noncrop grasses adjacent to rice (Oryza sativa L.) fields. Three farms in the Texas rice Gulf Coast production area were surveyed every 6-8 wk between 2007 and 2009 using quadrat sampling along transects. Although D. saccharalis densities were relatively low, E. loftini average densities ranged from 0.3 to 5.7 immatures per m(2) throughout the 2-yr period. Early annual grasses including ryegrass, Lolium spp., and brome, Bromus spp., were infested during the spring, whereas the perennial johnsongrass, Sorghum halepense (L.) Pers., and Vasey's grass, Paspalum urvillei Steud., were infested throughout the year. Johnsongrass was the most prevalent host (41-78% relative abundance), but Vasey's grass (13-40% relative abundance) harbored as much as 62% of the recovered E. loftini immatures (during the winter). Young rice in newly planted fields did not host stem borers before June. April sampling in fallow rice fields showed that any available live grass material, volunteer rice or weed, can serve as a host during the spring. Our study suggests that noncrop grasses are year-round sources of E. loftini in Texas rice agroecosystems and may increase pest populations.

  13. Model estimation of land-use effects on water levels of northern prairie wetlands.

    Science.gov (United States)

    Voldseth, Richard A; Johnson, W Carter; Gilmanov, Tagir; Guntenspergen, Glenn R; Millett, Bruce V

    2007-03-01

    Wetlands of the Prairie Pothole Region exist in a matrix of grassland dominated by intensive pastoral and cultivation agriculture. Recent conservation management has emphasized the conversion of cultivated farmland and degraded pastures to intact grassland to improve upland nesting habitat. The consequences of changes in land-use cover that alter watershed processes have not been evaluated relative to their effect on the water budgets and vegetation dynamics of associated wetlands. We simulated the effect of upland agricultural practices on the water budget and vegetation of a semipermanent prairie wetland by modifying a previously published mathematical model (WETSIM). Watershed cover/land-use practices were categorized as unmanaged grassland (native grass, smooth brome), managed grassland (moderately heavily grazed, prescribed burned), cultivated crops (row crop, small grain), and alfalfa hayland. Model simulations showed that differing rates of evapotranspiration and runoff associated with different upland plant-cover categories in the surrounding catchment produced differences in wetland water budgets and linked ecological dynamics. Wetland water levels were highest and vegetation the most dynamic under the managed-grassland simulations, while water levels were the lowest and vegetation the least dynamic under the unmanaged-grassland simulations. The modeling results suggest that unmanaged grassland, often planted for waterfowl nesting, may produce the least favorable wetland conditions for birds, especially in drier regions of the Prairie Pothole Region. These results stand as hypotheses that urgently need to be verified with empirical data.

  14. Ciclo de vida de Anasa litigiosa (Hemiptera: Heteroptera: Coreidae Life cycle of Anasa litigiosa (Hemiptera: Heteroptera: Coreidae

    Directory of Open Access Journals (Sweden)

    Adriana Chacón-López

    2012-06-01

    Full Text Available El objetivo de este trabajo es el estudio del ciclo de vida de Anasa litigiosa Stål. Se recolectaron ejemplares adultos de esta especie que se encontraban sobre plantas de chayote y fueron cultivados en el laboratorio utilizando hojas, tallos y frutos de la misma planta. Se describen e ilustran en detalle todos los estadios de vida, incluyendo notas sobre su biología. Anasa litigiosa se ha recolectado sobre bromeliáceas y cucurbitáceas y es una plaga importante de estas últimas.The aim of this work was the study of the life cycle of Anasa litigiosa Stål. Adults were collected on chayote and they were reared in laboratory using leaves, stems and fruits of chayote. Descriptions and illustrations of all instars of, and notes on its biology are included. This species has been collected in bromeliads and on cucurbits, it is an important pest of cucurbits in Mexico.

  15. Syngas Production from Pyrolysis of Nine Composts Obtained from Nonhybrid and Hybrid Perennial Grasses

    Directory of Open Access Journals (Sweden)

    Adéla Hlavsová

    2014-01-01

    Full Text Available A pyrolysis of compost for the production of syngas with an explicit H2/CO = 2 or H2/CO = 3 was investigated in this study. The composts were obtained from nonhybrid (perennial grasses (NHG and hybrid (perennial grasses (HG. Discrepancies in H2 evolution profiles were found between NHG and HG composts. In addition, positive correlations for NHG composts were obtained between (i H2 yield and lignin content, (ii H2 yield and potassium content, and (iii CO yield and cellulose content. All composts resulted in H2/CO = 2 and five of the nine composts resulted in H2/CO = 3. Exceptionally large higher heating values (HHVs of pyrolysis gas, very close to HHVs of feedstock, were obtained for composts made from mountain brome (MB, 16.23 MJ/kg, hybrid Becva (FB, 16.45 MJ/kg, and tall fescue (TF, 17.43 MJ/kg. The MB and FB composts resulted in the highest syngas formation with H2/CO = 2, whereas TF compost resulted in the highest syngas formation with H2/CO = 3.

  16. Examining the Heterogeneous Genome Content of Multipartite Viruses BMV and CCMV by Native Mass Spectrometry

    Science.gov (United States)

    van de Waterbeemd, Michiel; Snijder, Joost; Tsvetkova, Irina B.; Dragnea, Bogdan G.; Cornelissen, Jeroen J.; Heck, Albert J. R.

    2016-06-01

    Since the concept was first introduced by Brian Chait and co-workers in 1991, mass spectrometry of proteins and protein complexes under non-denaturing conditions (native MS) has strongly developed, through parallel advances in instrumentation, sample preparation, and data analysis tools. However, the success rate of native MS analysis, particularly in heterogeneous mega-Dalton (MDa) protein complexes, still strongly depends on careful instrument modification. Here, we further explore these boundaries in native mass spectrometry, analyzing two related endogenous multipartite viruses: the Brome Mosaic Virus (BMV) and the Cowpea Chlorotic Mottle Virus (CCMV). Both CCMV and BMV are approximately 4.6 megadalton (MDa) in mass, of which approximately 1 MDA originates from the genomic content of the virion. Both viruses are produced as mixtures of three particles carrying different segments of the genome, varying by approximately 0.1 MDA in mass (~2%). This mixture of particles poses a challenging analytical problem for high-resolution native MS analysis, given the large mass scales involved. We attempt to unravel the particle heterogeneity using both Q-TOF and Orbitrap mass spectrometers extensively modified for analysis of very large assemblies. We show that manipulation of the charging behavior can provide assistance in assigning the correct charge states. Despite their challenging size and heterogeneity, we obtained native mass spectra with resolved series of charge states for both BMV and CCMV, demonstrating that native MS of endogenous multipartite virions is feasible.

  17. An adaptive approach to invasive plant management on U.S. Fish and Wildlife Service-owned native prairies in the Prairie Pothole Region: decision support under uncertainity

    Science.gov (United States)

    Gannon, Jill J.; Moore, Clinton T.; Shaffer, Terry L.; Flanders-Wanner, Bridgette

    2011-01-01

    Much of the native prairie managed by the U.S. Fish and Wildlife Service (Service) in the Prairie Pothole Region (PPR) is extensively invaded by the introduced cool-season grasses smooth brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis). The central challenge to managers is selecting appropriate management actions in the face of biological and environmental uncertainties. We describe the technical components of a USGS management project, and explain how the components integrate and inform each other, how data feedback from individual cooperators serves to reduce uncertainty across the whole region, and how a successful adaptive management project is coordinated and maintained on a large scale. In partnership with the Service, the U.S. Geological Survey is developing an adaptive decision support framework to assist managers in selecting management actions under uncertainty and maximizing learning from management outcomes. The framework is built around practical constraints faced by refuge managers and includes identification of the management objective and strategies, analysis of uncertainty and construction of competing decision models, monitoring, and mechanisms for model feedback and decision selection. Nineteen Service field stations, spanning four states of the PPR, are participating in the project. They share a common management objective, available management strategies, and biological uncertainties. While the scope is broad, the project interfaces with individual land managers who provide refuge-specific information and receive updated decision guidance that incorporates understanding gained from the collective experience of all cooperators.

  18. Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection.

    Science.gov (United States)

    Zhu, Min; Chen, Yuting; Ding, Xin Shun; Webb, Stephen L; Zhou, Tao; Nelson, Richard S; Fan, Zaifeng

    2014-09-01

    The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  19. Ação de quitosana sobre o desenvolvimento de Plasmopara viticola e Elsinoe ampelina, in vitro e em videiras cv. Isabel Chitosan action on Plasmopara viticola and Elsinoe ampelina development in vitro and in grapevines cv. Isabel

    Directory of Open Access Journals (Sweden)

    Aline José Maia

    2010-09-01

    Full Text Available Este trabalho teve como objetivos avaliar o efeito da quitosana no controle dos fungos Plasmopara viticola e Elsinoe ampelina, agentes causais do míldio e da antracnose da videira, respectivamente. As concentrações de 0, 20, 40, 80 e 160 mg L-1 de quitosana foram utilizadas nos seguintes experimentos: testes de crescimento micelial, de germinação de esporos e ensaio em condições de campo. Para os dois últimos ensaios, adicionou-se tratamentos padrões com mancozeb e calda bordalesa. Verificou-se redução no crescimento micelial de E. ampelina sendo que a maior concentração de quitosana (160 mg L-1 reduziu em 57% o desenvolvimento do fungo, 192 horas após incubação. Nos testes de germinação, a dose de 160 mg L-1 de quitosana reduziu a germinação de esporos de E. ampelina em aproximadamente 98% e de P. viticola em 60%, não diferindo dos tratamentos com calda bordalesa e mancozeb. Nos ensaios a campo as maiores doses de quitosana (80 e 160 mg L-1 apresentaram um decréscimo na severidade de antracnose entre 93 e 81%. Para o míldio, a concentração de 160 mg L-1 apresentou um decréscimo de aproximadamente 81%. Baseando-se nestes resultados, pode-se concluir que a quitosana tem um grande potencial no controle do míldio e da antracnose da videira.This work aimed to evaluate the effect of chitosan on the control of fungi Elsinoe ampelina and Plasmopara viticola, the causal agents of downy mildew and anthracnose in grapevines, respectively. The concentrations of 0, 20, 40, 80 and 160 mg L-1 chitosan were used in the following trials: mycelial growth, spore germination, and experiment in field conditions. For the last two trials standard treatments with mancozeb and bordeax mixture were added. There was a reduction in E. ampelina mycelial growth and the highest chitosan concentration (160 mg L-1 decreased by 57% the fungus development at 192 hours after incubation. In the germination tests, the concentration of 160 mg L-1 chitosan

  20. Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

    Science.gov (United States)

    Arneth, A.; Veenendaal, E. M.; Best, C.; Timmermans, W.; Kolle, O.; Montagnani, L.; Shibistova, O.

    2006-09-01

    We compare assimilation and respiration rates, and water use strategies in four divergent ecosystems located in cold-continental central Siberia and in semi-arid southern Africa. These seemingly unrelated systems have in common a harsh and highly seasonal environment with a very sharp transition between the dormant and the active season, with vegetation facing dry air and soil conditions for at least part of the year. Moreover, the northern high latitudes and the semi-arid tropics will likely experience changes in key environmental parameters (e.g., air temperature and precipitation) in the future; indeed, in some regions marked climate trends have already been observed over the last decade or so. The magnitude of instantaneous or daily assimilation and respiration rates, derived from one to two years of eddy covariance measurements in each of the four ecosystems, was not related to the growth environment. For instance, respiration rates were clearly highest in the two deciduous systems included in the analysis (a Mopane woodland in northern Botswana and a Downy birch forest in Siberia; >300 mmol m-2 d-1), while assimilation rates in the Mopane woodland were relatively similar to a Siberian Scots pine canopy for a large part of the active season (ca. 420 mmol m-2 d-1). Acknowledging the limited number of ecosystems compared here, these data nevertheless demonstrate that factors like vegetation type, canopy phenology or ecosystem age can override larger-scale climate differences in terms of their effects on carbon assimilation and respiration rates. By far the highest rates of assimilation were observed in Downy birch, an early successional species. These were achieved at a rather conservative water use, as indicated by relatively low levels of λ, the marginal water cost of plant carbon gain. Surprisingly, the Mopane woodland growing in the semi-arid environment had significantly higher values of λ. However, its water use strategy included a very plastic response

  1. Management of hirsutism.

    Science.gov (United States)

    Callan, A

    1982-12-01

    This discussion of the management of hirsutism focuses on clinical assessment, investigations, evaluation of treatment methods, therapeutic regimens, medical therapy, cosmetic therapy, and supportive therapy for hirsute women. Initial clinical evaluation of the hirsute woman should consider the site, type, and extent or area of hair growth as well as age of onset and rate of appearance. In part what is normal is determined by societal attitudes and cultural norms, and it may be that a woman seeking treatment for hirsutism is simply over concerned by a normal growth pattern. A well defined coarse growth of hair on the chin and cheeks of sudden onset at any age suggests an underlying endocrine problem, whereas women with fine downy facial hair, even when this is extensive, are less likely to have an endocrine disturbance than those with a coarse growth. Data about family history, ethnic background, age of onset, and rate of appearance will help identify those cases needing more detailed investigation. Physical examination included pelvic examination to exclude ovarian enlargement and examination of genitals to exclude clitoral hypertrophy together with assessment of the overall severity of hirsutism will further define those patients who require further investigation. Urinary 24 hour 17 ketosteroid excretion and plasma androgens should be estimated as a baseline investigation to identify those patients whose hirsutism is due to androgen secreting tumors or adrenal hyperplasia. Testosterone production rate and testosterone metabolic clearance rate have been shown to be well increased in hirsute women and to correlate well with severity of hirsutism. In certain patients laboratory evidence may suggest either the ovaries or the adrenals as the major source of androgen excess. The ideal response to treatment is reduced growth rate and reversion of coarse, dark, terminal hair to a lighter, more downy growth. There is no uniformly reliable, simple, objective method of

  2. Características morfológicas e fitossanitárias de variedades de roseira na etapa de classificação Morphological and fitossanitary characteristics in rose varieties on classification stage

    Directory of Open Access Journals (Sweden)

    Beatriz Meireles Barguil

    2010-07-01

    Full Text Available A qualidade da haste floral de roseira é afetada por inúmeros defeitos, como botão pequeno ou presença de doenças e ferimentos. Este trabalho teve como objetivo avaliar as características morfológicas (comprimento e retidão da haste e do botão floral e fitossanitárias (incidência de míldio, oídio, mofo cinzento e dano causado por lagarta de sete variedades de roseira cultivadas em ambiente protegido. As características foram observadas em três avaliações. O comprimento médio de haste floral variou de 56,1 a 83,3cm, enquanto que o comprimento médio dos botões variou de 4,7 a 5,2cm. Foram observados sintomas de míldio, oídio, mofo cinzento e injúria causada por lagarta nas hastes florais, sendo o oídio o principal problema fitossanitário observado, tendo afetado de 2,9 a 41,3% das hastes, dependendo da variedade. Cerca de 70% das hastes de cada variedade apresentaram características do tipo de C ou D durante a etapa de classificação. Esses resultados reforçam a necessidade da avaliação das diversas características das variedades adquiridas, antes da implementação do cultivo comercial.The quality of the rose's floral stem can be affected by numerous faults as small button or diseases and injuries. This study aimed to evaluate the morphological (length and rightness of stem and rose bud and fitossanitary (downy mildew, powdery mildew, gray mold and caterpillar damage characteristics in seven varieties of rose grown in a greenhouse. The characteristics were analyzed three times. The average length of floral stems ranged from 56.1 to 83.3cm, while the average length of buttons ranged from 4.7 to 5.2cm in the varieties evaluated. Symptoms of downy mildew, powdery mildew, gray mold and damage caused by caterpillar were observed, although powdery mildew were the main problem witch affect from 2,9 to 41,3% of floral stems. About 70% of the stems of all varieties showed characteristics of type C or D during the

  3. Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

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    O. Kolle

    2006-04-01

    Full Text Available We compare assimilation and respiration rates, and water use strategies in four divergent ecosystems located in cold-continental central Siberia and in semi-arid southern Africa. These seemingly unrelated systems have in common a harsh and highly seasonal environment with a very sharp transition between the dormant and the active season, and with vegetation facing dry air and soil conditions for at least part of the year. Moreover, the northern high latitudes and the semi-arid tropics will likely experience changes in key environmental parameters (e.g., air temperature and precipitation in the future; indeed, in some regions marked climate trends have already been observed over the last decade or so. The magnitude of instantaneous or daily assimilation and respiration rates, derived from one to two years of eddy covariance measurements in each of the four ecosystems, was not related to the growth environment. For instance, respiration rates were clearly highest in the two deciduous systems included in the analysis (a Mopane woodland in northern Botswana and a Downy birch forest in Siberia; >300 mmol m−2 d−1, while assimilation rates in the Mopane woodland were relatively similar to a Siberian Scots pine canopy for a large part of the active season (ca. 420 mmol m−2 d−1. Acknowledging the limited number of ecosystems compared here, these data nevertheless suggest that factors like vegetation type, canopy phenology or ecosystem age can override larger-scale climate differences in terms of their effects on carbon assimilation and respiration rates. By far the highest rates of assimilation were observed in Downy birch, an early successional species. These were achieved at a rather conservative water use, as indicated by relatively low levels of λ, the marginal water cost of plant carbon gain. Surprisingly, the Mopane woodland growing in the semi-arid environment had significantly higher values of λ. However, its water use strategy

  4. PERAKITAN VARIETAS HIBRIDA JAGUNG MANIS BERDAYA HASIL TINGGI DAN TAHAN TERHADAP PENYAKIT BULAI

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    Sriani Sujiprihati

    2012-12-01

    Full Text Available Sweet corn is a result of recessive mutation which occurs naturally in gene that controls the conversion of sugar into starch in corn seed endosperm. There are 3 main genes that affect corn sweetness, namely sugary gene (su, sugary enhancer gene (se, and shrunken gene (sh2. This study aims to obtain a general combining ability value for the sweet corn lines, which will be the parent in diallel crosses; obtain the information of general combining ability, specific combining ability, and heterosis value for sweet corn lines; and obtain one or more promising single cross hybrids that will be potential for high yield and resistance to downy mildew disease. The study was conducted from April 2009 until November 2011 at the Experimental Field Centre for Cereal Plant Study (BALITSEREAL, Maros, South Sulawesi. The results showed that five genotypes had moderately high yield: Mr4/SC/BC4-3-1B, Mr14/SC/BC4-6-1B, Mr11/SC/BC4-3-1B, Mr14/SC/BC3-8-1B, and Mr12/SC/BC4-6-1B. The attack level of downy mildew that was classified as resistant has 0 to 7% rate. The combination of crosses that produce better productivity than all the varieties are: C × A (Mr11/SC/BC4-2-1B-1 × Mr12/SC/BC4-5-B-1, A × D (Mr12/SC/BC4-5-B-1 × Mr11/SC/BC4-2-1B-1, E × B (Mr12/SC/BC3-3-1B -1 × Mr14/SC/BC4-6-1B-1, and B × D (Mr11/SC/BC4-2-1B-1 × Mr14/SC/BC4-6-1B-1 . Five hybrids can be continued for the preliminary testing of yields. Twelve candidate varieties do not have yield different than the checked varieties, so it can proceed to a multilocation trials to explore the advantages that can be released as new varieties.

  5. Genotyping-by-Sequencing Uncovers the Introgression Alien Segments Associated with Sclerotinia Basal Stalk Rot Resistance from Wild Species-I. Helianthus argophyllus and H. petiolaris.

    Science.gov (United States)

    Qi, Lili; Long, Yunming; Talukder, Zahirul I; Seiler, Gerald J; Block, Charles C; Gulya, Thomas J

    2016-01-01

    Basal stalk rot (BSR), caused by Sclerotinia sclerotiorum, is a devastating disease in sunflower worldwide. The progress of breeding for Sclerotinia BSR resistance has been hampered due to the lack of effective sources of resistance for cultivated sunflower. Our objective was to transfer BSR resistance from wild annual Helianthus species into cultivated sunflower and identify the introgressed alien segments associated with BSR resistance using a genotyping-by-sequencing (GBS) approach. The initial crosses were made between the nuclear male sterile HA 89 with the BSR resistant plants selected from wild Helianthus argophyllus and H. petiolaris populations in 2009. The selected resistant F1 plants were backcrossed to HA 458 and HA 89, respectively. Early generation evaluations of BSR resistance were conducted in the greenhouse, while the BC2F3 and subsequent generations were evaluated in the inoculated field nurseries. Eight introgression lines; six from H. argophyllus (H.arg 1 to H.arg 6), and two from H. petiolaris (H.pet 1 and H.pet 2), were selected. These lines consistently showed high levels of BSR resistance across seven environments from 2012 to 2015 in North Dakota and Minnesota, USA. The mean BSR disease incidence (DI) for H.arg 1 to H.arg 6, H.pet 1, and H.pet 2 was 3.0, 3.2, 0.8, 7.2, 7.7, 1.9, 2.5, and 4.4%, compared to a mean DI of 36.1% for Cargill 270 (susceptible hybrid), 31.0% for HA 89 (recurrent parent), 19.5% for HA 441 (resistant inbred), and 11.6% for Croplan 305 (resistant hybrid). Genotyping of the highly BSR resistant introgression lines using GBS revealed the presence of the H. argophyllus segments in linkage groups (LGs) 3, 8, 9, 10, and 11 of the sunflower genome, and the H. petiolaris segments only in LG8. The shared polymorphic SNP loci in the introgression lines were detected in LGs 8, 9, 10, and 11, indicating the common introgression regions potentially associated with BSR resistance. Additionally, a downy mildew resistance gene, Pl17

  6. Study on fungicide resistance of Pseudoperonospora cubensis to azoxystrobin%黄瓜霜霉菌对嘧菌酯抗药性的研究

    Institute of Scientific and Technical Information of China (English)

    张艳菊; 王莹; 党悦嘉; 柴洪庆

    2015-01-01

    Azoxystrobin is a strobilurin fungicide, it has a broad antimicrobial spectrum and high activity, but at the same time the agent also runs the risk of becoming a resistance agent. In order to understand the resistance of the cucumber downy mildew's (Pseudoperonospora cubensis) sensitivity to azoxystrobin, 36 cucumber downy mildew isolates were tested using the leaf disk floating method. The isolates were collected from 13 production areas over eight provinces:Heilongjiang, Jilin, Liaoning, Beijing, Shandong, Jiangsu, Hubei and Guangdong. EC50 of Pseudoperonospora cubensis to azoxy-strobin was 0.0107-0.2408μg·mL-1 and the average EC50 was 0.1004μg·mL-1. Of the 36 strains, 26 had a medium level of resistance, nine had low resistance, one was sensitive and none were highly resistant. The resistance level of Shandong Province strains to azoxystrobin was the highest and the resistance levels of other provinces' resistant strains to azoxystrobin were relatively low.%嘧菌酯为甲氧基丙烯酸酯类杀菌剂,具有杀菌谱广、杀菌活性高等优点,但同时该类药剂也属于高抗性风险药剂。为明确我国黄瓜主产区黄瓜霜霉菌对嘧菌酯的抗药性,采用叶盘漂浮法测定来自黑龙江、吉林、辽宁、北京、山东、江苏、湖北和广东8个省份13个黄瓜主产区36个黄瓜霜霉病菌(Pseudoperonospora cubensis)菌株对嘧菌酯的抗药性。黄瓜霜霉菌对嘧菌酯的EC50值为0.0107~0.2408μg·mL-1,平均EC50值为0.1004μg·mL-1。36个菌株中有26个中抗菌株、9个低抗菌株和1个敏感菌株,无高抗菌株。山东省菌株对嘧菌酯的抗性水平最高,其余省份菌株对嘧菌酯抗性水平相对较低。

  7. 叶片湿润时间对葡萄霜霉病发生状况的影响%Effect of Different Humidity Time on Occurrence of Plasmopara viticola in Grape

    Institute of Scientific and Technical Information of China (English)

    沙月霞; 王国珍; 樊仲庆

    2011-01-01

    The experiments set up different time of leaves infected by fungal suspension, different humidity time of leaves inoculated by Plasmorara viticola and different humidity condition in laboratory to explore the effect of different thumidity time on occurrence extent of Plasmopara viticola on grape leaves. Results showed that grape downy mildew would take place when grape leaves were infected by fungal suspension beyond 0. 5 h and the severity of disease became worse with time enlongation. The humid condition of grape downy mildew was beyond RH 76. 00% and disease was worse with higher humid. The key condition for Plasmorara viticola infection and disease apparition was keeping humidity beyond 2 -3 h. The shortest incubation period of Plasmorara viticola was 2~3 d at 20 °C. The highest apparition period of disease was 5 - 7 d after wetting grape blade back.%从不同菌悬液与叶片接触时间、接菌后叶片不同保湿时间和不同保湿条件3方面,研究叶片湿润时间对葡萄霜霉病发生状况的影响.结果表明,葡萄霜霉病菌悬液与叶片接触0.5h以上即可导致霜霉病发生,接触时间越长发病越重;接菌后在RH=76%保湿条件下,葡萄霜霉病即发生,湿度越高发病越重;霜霉病菌完成侵入到显症需要的叶片湿润条件是叶片湿润2~3 h以上;20℃条件下,霜霉病的潜伏期最短2~3 d,而病斑出现的高峰期是使叶背湿润后的5~7 d.

  8. Multiple candidate effectors from the oomycete pathogen Hyaloperonospora arabidopsidis suppress host plant immunity.

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    Georgina Fabro

    2011-11-01

    Full Text Available Oomycete pathogens cause diverse plant diseases. To successfully colonize their hosts, they deliver a suite of effector proteins that can attenuate plant defenses. In the oomycete downy mildews, effectors carry a signal peptide and an RxLR motif. Hyaloperonospora arabidopsidis (Hpa causes downy mildew on the model plant Arabidopsis thaliana (Arabidopsis. We investigated if candidate effectors predicted in the genome sequence of Hpa isolate Emoy2 (HaRxLs were able to manipulate host defenses in different Arabidopsis accessions. We developed a rapid and sensitive screening method to test HaRxLs by delivering them via the bacterial type-three secretion system (TTSS of Pseudomonas syringae pv tomato DC3000-LUX (Pst-LUX and assessing changes in Pst-LUX growth in planta on 12 Arabidopsis accessions. The majority (~70% of the 64 candidates tested positively contributed to Pst-LUX growth on more than one accession indicating that Hpa virulence likely involves multiple effectors with weak accession-specific effects. Further screening with a Pst mutant (ΔCEL showed that HaRxLs that allow enhanced Pst-LUX growth usually suppress callose deposition, a hallmark of pathogen-associated molecular pattern (PAMP-triggered immunity (PTI. We found that HaRxLs are rarely strong avirulence determinants. Although some decreased Pst-LUX growth in particular accessions, none activated macroscopic cell death. Fewer HaRxLs conferred enhanced Pst growth on turnip, a non-host for Hpa, while several reduced it, consistent with the idea that turnip's non-host resistance against Hpa could involve a combination of recognized HaRxLs and ineffective HaRxLs. We verified our results by constitutively expressing in Arabidopsis a sub-set of HaRxLs. Several transgenic lines showed increased susceptibility to Hpa and attenuation of Arabidopsis PTI responses, confirming the HaRxLs' role in Hpa virulence. This study shows TTSS screening system provides a useful tool to test whether

  9. Análise da diversidade genética por AFLP e identificação de marcadores associados à resistência a doenças em videira Genetic diversity and identification of AFLP markers associated with diseases resistance in grapevine

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    Paulo Ricardo Dias de Oliveira

    2005-12-01

    Full Text Available Com objetivo de estudar diversidade genética e identificar marcadores associados à resistência ao míldio (Plasmopara viticola e ao oídio (Uncinula necator, foram analisadas as cultivares de videira A 1976, CG 87746, CNPUV 154-27, Crimson Seedless, Gota de Ouro, Itália, Seyve Villard 12327 e Seyve Villard 12375. As análises de polimorfismo de comprimento de fragmento amplificado (AFLP seguiram as etapas de digestão, ligação, pré-amplificação e amplificação. Efetuou-se a separação dos fragmentos amplificados em gel de 7% de poliacrilamida desnaturante (uréia 7M e coloração com nitrato de prata. A similaridade foi estimada com base no coeficiente de Jaccard, e a agregação, por UPGMA. Foi gerada uma matriz de similaridade com bom ajustamento da agregação (r = 0,84. Os agrupamentos obtidos corresponderam à origem e classificação botânica das cultivares. Foram identificadas 15 marcas dissimilares associadas à resistência, sendo oito para míldio e sete para oídio.The grapevine cultivars A 1976, CG 87746, CNPUV 154-27, Crimson Seedless, Gota de Ouro, Itália, Seyve Villard 12327 and Seyve Villard 12375 were analyzed to establish the genetic relationship and to identify markers associated with resistance to downy mildew (Plasmopara viticola and powdery mildew (Uncinula necator. The amplified fragment lenght polymorphism (AFLP analysis comprise the steps of digestion, ligation, preamplification and amplification. The amplified fragments were separeted on a 7% denaturing polyacrylamide gel (7M urea and silver stained. The similarity was estimated using Jaccard's coefficient and the clustering was estimated by UPGMA. A similarity matrix was generated with a good fit for aggregation (r = 0,84. The clusters corresponded to origin and botany classification of the cultivars. Fifteen markers were associated with resistance, eight for downy mildew and seven for powdery mildew.

  10. Contrasting patterns of groundwater evapotranspiration in grass and tree dominated riparian zones of a temperate agricultural catchment

    Science.gov (United States)

    Satchithanantham, Sanjayan; Wilson, Henry F.; Glenn, Aaron J.

    2017-06-01

    Consumptive use of shallow groundwater by phreatophytic vegetation is a significant part of the water budget in many regions, particularly in riparian areas. The influence of vegetation type on groundwater level fluctuations and evapotranspiration has rarely been quantified for contrasting plant communities concurrently although it has implications for downstream water yield and quality. Hourly groundwater evapotranspiration (ETG) rates were estimated for grass and tree riparian vegetation in southwestern Manitoba, Canada using two modified White methods. Groundwater table depth was monitored in four 21 m transects of five 3 m deep monitoring wells in the riparian zone of a stream reach including tree (Acer negundo; boxelder) and grass (Bromus inermis; smooth brome) dominated segments. The average depths to the groundwater table from the surface were 1.4 m and 1 m for the tree and grass segments, respectively, over the two-year study. During rain free periods of the growing season ETG was estimated for a total of 70 days in 2014 and 79 days in 2015 when diurnal fluctuations were present in groundwater level. Diurnal groundwater level fluctuations were observed during dry periods under both segments, however, ETG was significantly higher (p total ETG was approximately 50% (148 mm) and 100% (282-285 mm) of reference evapotranspiration (ETref, 281 mm) for the grass and tree segments, respectively. In 2015, total ETG was approximately 40% (106-127 mm) and 120% (369-374 mm) of ETref (307 mm) for the grass and tree segments, respectively. Results from the study show the tree dominated portions of the stream reach consumed approximately 2.4 ML ha-1 yr-1 more groundwater than a common forage grass. These findings have land management implications for regional water budgets during wet periods when flood mitigation is desirable and dry years when water scarcity is a concern.

  11. Status and management of non-native plant invasion in three of the largest national parks in the United States

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    Scott Abella

    2015-06-01

    Full Text Available Globally, invasion by non-native plants threatens resources that nature reserves are designated to protect. We assessed the status of non-native plant invasion on 1,662, 0.1-ha plots in Death Valley National Park, Mojave National Preserve, and Lake Mead National Recreation Area. These parks comprise 2.5 million ha, 23% of the national park land in the contiguous USA. At least one non-native species inhabited 82% of plots. Thirty-one percent of plots contained one non-native species, 30% two, 17% three, and 4% four to ten non-native species. Red brome (Bromus rubens, an ‘ecosystem engineer’ that alters fire regimes, was most widespread, infesting 60% of plots. By identifying frequency of species through this assessment, early detection and treatment can target infrequent species or minimally invaded sites, while containment strategies could focus on established invaders. We further compared two existing systems for prioritizing species for management and found that a third of species on plots had no rankings available. Moreover, rankings did not always agree between ranking systems for species that were ranked. Presence of multiple non-native species complicates treatment, and while we found that 40% of plots contained both forb and grass invaders, exploiting accelerated phenology of non-natives (compared to native annuals might help manage multi-species invasions. Large sizes of these parks and scale of invasion are formidable challenges for management. Yet, precisely because of their size, these reserves represent opportunities to conserve large landscapes of native species by managing non-native plant invasions.

  12. Production of cucumber mosaic virus RNA5 and its role in recombination.

    Science.gov (United States)

    de Wispelaere, Melissanne; Rao, A L N

    2009-02-05

    Cucumber Mosaic Virus (CMV) is a plant infecting tripartite positive-strand RNA virus. In addition to three genomic and two known subgenomic RNAs, CMV strains of subgroup II (e.g. Q-CMV), but not subgroup I (e.g. Fny-CMV), produce and package a redundant RNA5 encompassing the 3' 304-307 nucleotides of RNAs 2 and 3. The mechanism regulating RNA5 production and its role in CMV life cycle is unknown. In this study, transient expression of Q2 or Q3 by agroinfiltration into Nicotiana benthamiana plants resulted in efficient accumulation of RNA5 suggesting that its production is independent of CMV replication. Deletion and point mutations engineered into a highly conserved region (Box1) adjacent to the 5' end of RNA5 identified sequences required for its efficient production. An experimental system, involving a chimera of Q3 (Q3B3) characterized by having a 3' tRNA-like structure (3'TLS) from Brome mosaic virus (BMV) and RNA5 defective variants of Q1 (Q1Delta), Q2 (Q2Delta) and Q3B3 (Q3DeltaB3), was used to evaluate in vivo the contribution of RNA5 in promoting RNA recombination. Generation of precise homologous recombinants was strictly dependent on sequence identity. When both parental RNAs carried the Box1, recombination occurred preferentially within the Box1. In contrast, generation of non-homologous recombinants occurred only when Q1 and Q2 were competent to produce RNA5. A mechanistic model explaining the functional role played by the RNA5 in generating CMV recombinants was presented.

  13. Comparative Study of Non-Enveloped Icosahedral Viruses Size.

    Science.gov (United States)

    Nikitin, Nikolai; Trifonova, Ekaterina; Evtushenko, Evgeniy; Kirpichnikov, Mikhail; Atabekov, Joseph; Karpova, Olga

    2015-01-01

    Now, as before, transmission electron microscopy (TEM) is a widely used technique for the determination of virions size. In some studies, dynamic light scattering (DLS) has also been applied for this purpose. Data obtained by different authors and using different methods could vary significantly. The process of TEM sample preparation involves drying on the substrate, which can cause virions to undergo morphology changes. Therefore, other techniques should be used for measurements of virions size in liquid, (i.e. under conditions closer to native). DLS and nanoparticle tracking analysis (NTA) provide supplementary data about the virions hydrodynamic diameter and aggregation state in liquid. In contrast to DLS, NTA data have a higher resolution and also are less sensitive to minor admixtures. In the present work, the size of non-enveloped icosahedral viruses of different nature was analyzed by TEM, DLS and NTA: the viruses used were the encephalomyocarditis virus (animal virus), and cauliflower mosaic virus, brome mosaic virus and bean mild mosaic virus (plant viruses). The same, freshly purified, samples of each virus were used for analysis using the different techniques. The results were compared with earlier published data and description databases. DLS data about the hydrodynamic diameter of bean mild mosaic virus, and NTA data for all examined viruses, were obtained for the first time. For all virus samples, the values of size obtained by TEM were less than virions sizes determined by DLS and NTA. The contribution of the electrical double layer (EDL) in virions hydrodynamic diameter was evaluated. DLS and NTA data adjusted for EDL thickness were in better agreement with TEM results.

  14. Comparative Study of Non-Enveloped Icosahedral Viruses Size.

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    Nikolai Nikitin

    Full Text Available Now, as before, transmission electron microscopy (TEM is a widely used technique for the determination of virions size. In some studies, dynamic light scattering (DLS has also been applied for this purpose. Data obtained by different authors and using different methods could vary significantly. The process of TEM sample preparation involves drying on the substrate, which can cause virions to undergo morphology changes. Therefore, other techniques should be used for measurements of virions size in liquid, (i.e. under conditions closer to native. DLS and nanoparticle tracking analysis (NTA provide supplementary data about the virions hydrodynamic diameter and aggregation state in liquid. In contrast to DLS, NTA data have a higher resolution and also are less sensitive to minor admixtures. In the present work, the size of non-enveloped icosahedral viruses of different nature was analyzed by TEM, DLS and NTA: the viruses used were the encephalomyocarditis virus (animal virus, and cauliflower mosaic virus, brome mosaic virus and bean mild mosaic virus (plant viruses. The same, freshly purified, samples of each virus were used for analysis using the different techniques. The results were compared with earlier published data and description databases. DLS data about the hydrodynamic diameter of bean mild mosaic virus, and NTA data for all examined viruses, were obtained for the first time. For all virus samples, the values of size obtained by TEM were less than virions sizes determined by DLS and NTA. The contribution of the electrical double layer (EDL in virions hydrodynamic diameter was evaluated. DLS and NTA data adjusted for EDL thickness were in better agreement with TEM results.

  15. Aspen (Populus tremuloides Michx.) intake and preference by mammalian herbivores: the role of plant secondary compounds and nutritional context.

    Science.gov (United States)

    Villalba, Juan J; Burritt, Elizabeth A; St Clair, Samuel B

    2014-10-01

    Aspen (Populus tremuloides Michx.) has evolved a chemical defense system comprised of phenolic glycosides (PG), which effectively deter insect herbivory. However, much less is known about the role of PG and the nutritional quality of the associated plant community on aspen browse susceptibility to mammalian herbivores. In three successive periods during the growing season, we conducted experiments with sheep by offering leaves from two aspen stands with different concentrations of PG (LOW, HIGH) or aspen leaves vs. leaves from a forb (Utah pea, Lathyrus pauciflorus) or a grass (smooth brome, Bromus inermis Leyss.) growing in an aspen understory. Intake of aspen (19 to 35 % PG) was low in all periods (1 to 6 g/Kg(0.75) in 2 hr) supporting the notion that aspen's defense system may contribute to its ecological success. However, lambs ate larger amounts of LOW than of HIGH suggesting that sheep could discriminate between aspen stands with different concentrations of PG, even when both stands were relatively well defended. Concentration of nutrients and chemical defenses in aspen leaves remained fairly stable across the growing season, and preference for aspen increased over the growing season. In contrast, preference for the forb and the grass decreased across the growing season in concert with a decline in the nutritional quality of these plants. The data suggest that nutritional context of aspen and associated forage species drove preference more than contrasts in defense chemistry of aspen. There may be periods of "susceptibility" of aspen use by mammalian herbivores, despite high concentrations of chemical defenses, which can potentially be targeted by management to reduce aspen herbivory.

  16. Precious grasses : Alberta Research Council releases new native species for reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Jaremko, D.

    2006-03-15

    The Alberta Research Council has released 6 new varieties of native plant species suitable for reclamation in Alberta's Parkland region, which is characterized by sandy soils. The Parkland stretches for 37,000 kilometres and is the most densely populated of the province's 6 ecoregions. Because of farming, grazing, oil and gas development and recreation, only 5 per cent of the area remains undisturbed. It was anticipated that the native grasses will help disturbed sites eventually resemble their original state. Varieties included: Aspen Milk Vetch; Centennial Canada Wild Rye; Hillbilly Nodding Brome; Butte Rocky Mountain Fescue; Porter Indian Rice Grass; and Metisko Awned Wheatgrass. The varieties were evaluated for their ability to provide rapid cover and their ability to compete with invading weeds, as well as their ability to allow recruitment of other native species. Multi-environmental testing trials were established to evaluate the species' seed production potential. Seeds were tested for germination in species-specific growth chambers, grown in greenhouses and then taken to an agricultural setting where data on forage density; ground cover; vigour; and biomass were then recorded. The species have also been targeted to ensure that the oil and gas industry has better options for reclaiming disturbed sites. In addition to their ability to combat threats from invasive species, the native plant species have been investigated for their ability to remediate hydrocarbon and salt contaminants and sequester carbon dioxide. Details of Alberta's current reclamation criteria for wellsites and associated facilities were also presented. 4 figs.

  17. Systematic identification of novel, essential host genes affecting bromovirus RNA replication.

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    Brandi L Gancarz

    Full Text Available Positive-strand RNA virus replication involves viral proteins and cellular proteins at nearly every replication step. Brome mosaic virus (BMV is a well-established model for dissecting virus-host interactions and is one of very few viruses whose RNA replication, gene expression and encapsidation have been reproduced in the yeast Saccharomyces cerevisiae. Previously, our laboratory identified ∼100 non-essential host genes whose loss inhibited or enhanced BMV replication at least 3-fold. However, our isolation of additional BMV-modulating host genes by classical genetics and other results underscore that genes essential for cell growth also contribute to BMV RNA replication at a frequency that may be greater than that of non-essential genes. To systematically identify novel, essential host genes affecting BMV RNA replication, we tested a collection of ∼900 yeast strains, each with a single essential gene promoter replaced by a doxycycline-repressible promoter, allowing repression of gene expression by adding doxycycline to the growth medium. Using this strain array of ∼81% of essential yeast genes, we identified 24 essential host genes whose depleted expression reproducibly inhibited or enhanced BMV RNA replication. Relevant host genes are involved in ribosome biosynthesis, cell cycle regulation and protein homeostasis, among other cellular processes. BMV 2a(Pol levels were significantly increased in strains depleted for a heat shock protein (HSF1 or proteasome components (PRE1 and RPT6, suggesting these genes may affect BMV RNA replication by directly or indirectly modulating 2a(Pol localization, post-translational modification or interacting partners. Investigating the diverse functions of these newly identified essential host genes should advance our understanding of BMV-host interactions and normal cellular pathways, and suggest new modes of virus control.

  18. Intersection of the multivesicular body pathway and lipid homeostasis in RNA replication by a positive-strand RNA virus.

    Science.gov (United States)

    Wang, Xiaofeng; Diaz, Arturo; Hao, Linhui; Gancarz, Brandi; den Boon, Johan A; Ahlquist, Paul

    2011-06-01

    Like many positive-strand RNA viruses, brome mosaic virus (BMV) RNA replication occurs in membrane-invaginated vesicular compartments. BMV RNA replication compartments show parallels with membrane-enveloped, budding retrovirus virions, whose release depends on the cellular multivesicular body (MVB) sorting pathway. BMV RNA replication compartments are not released from their parent membranes, but might depend on MVB functions for membrane invagination. Prior results show that BMV RNA replication is severely inhibited by deletion of the crucial MVB gene DOA4 or BRO1. We report here that involvement of DOA4 and BRO1 in BMV RNA replication is not dependent on the MVB pathway's membrane-shaping functions but rather is due to their roles in recycling ubiquitin from MVB cargos. We show that deleting DOA4 or BRO1 inhibits the ubiquitination- and proteasome-dependent activation of homologous transcription factors Mga2p and Spt23p, which regulate many lipid metabolism genes, including the fatty acid desaturase gene OLE1, which is essential for BMV RNA replication. However, Mga2p processing and BMV RNA replication are restored by supplementing free ubiquitin, which is depleted in doa4Δ and bro1Δ cells. The results identify Mga2p and Spt23p processing and lipid regulation as sensitive targets of ubiquitin depletion and correctly predict multiple effects of modulating additional host genes RFU1, UBP6, and UFD3. Our results also show that BMV RNA replication depends on additional Mga2p-regulated genes likely involved in lipid metabolism beyond OLE1. Among other points, these findings show the potential for blocking viral RNA replication by modulating lipid synthesis at multiple levels.

  19. Systematic identification of novel, essential host genes affecting bromovirus RNA replication.

    Science.gov (United States)

    Gancarz, Brandi L; Hao, Linhui; He, Qiuling; Newton, Michael A; Ahlquist, Paul

    2011-01-01

    Positive-strand RNA virus replication involves viral proteins and cellular proteins at nearly every replication step. Brome mosaic virus (BMV) is a well-established model for dissecting virus-host interactions and is one of very few viruses whose RNA replication, gene expression and encapsidation have been reproduced in the yeast Saccharomyces cerevisiae. Previously, our laboratory identified ∼100 non-essential host genes whose loss inhibited or enhanced BMV replication at least 3-fold. However, our isolation of additional BMV-modulating host genes by classical genetics and other results underscore that genes essential for cell growth also contribute to BMV RNA replication at a frequency that may be greater than that of non-essential genes. To systematically identify novel, essential host genes affecting BMV RNA replication, we tested a collection of ∼900 yeast strains, each with a single essential gene promoter replaced by a doxycycline-repressible promoter, allowing repression of gene expression by adding doxycycline to the growth medium. Using this strain array of ∼81% of essential yeast genes, we identified 24 essential host genes whose depleted expression reproducibly inhibited or enhanced BMV RNA replication. Relevant host genes are involved in ribosome biosynthesis, cell cycle regulation and protein homeostasis, among other cellular processes. BMV 2a(Pol) levels were significantly increased in strains depleted for a heat shock protein (HSF1) or proteasome components (PRE1 and RPT6), suggesting these genes may affect BMV RNA replication by directly or indirectly modulating 2a(Pol) localization, post-translational modification or interacting partners. Investigating the diverse functions of these newly identified essential host genes should advance our understanding of BMV-host interactions and normal cellular pathways, and suggest new modes of virus control.

  20. 贵州南部混播草地几种建植因素最佳组合研究%A Study on the Optimal Combination of a Few Establishing Factors on the Mix Sowing Grassland in South Guizhou.

    Institute of Scientific and Technical Information of China (English)

    莫本田; 罗天琼; 唐成斌; 韩永芬

    2000-01-01

    选用苇状羊茅、多年生黑麦草、扁穗雀麦、疏花雀麦、白三叶和紫花苜蓿等六种牧草,采用L9(34)正交试验设计,探讨了在贵州南部地区生态条件下建立永久型优质人工混播草地最佳的草种组合、豆禾比例、播种量和播种方式。结果表明,草种组合是主要因素,播种量次之,用种比例和播种方式无明显影响;贵州南部地区优质永久型人工混播草地的理想草种组合是苇状羊茅+多年生黑麦草+扁穗雀麦+白三叶(或紫花苜蓿),豆科和禾本科的比例是2∶8,播种量为30.0kg/hm2,播种方式为混种条播。%The optimal combinations of mixed sowing grassland in southern Guizhou were studied. The result indicated that species combination was the key factor, seeding rate was the second. The optimal combination of species was fescue + perennial rye, flat ear brome + white clover + alfalfa. The ratio of legumes to grasses was 2∶8, the seeding rate was 30.0kg/hm2, the sowing style was mixed drilling.

  1. The Longevity of Crop Seeds Stored Under Long-term Condition in the National Gene Bank of Bulgaria

    Directory of Open Access Journals (Sweden)

    Desheva Gergana

    2016-10-01

    Full Text Available Seed accessions from 7 plant families and 28 species stored for above 20 years in the National gene bank of Bulgaria were evaluated. All seed accessions were maintained as base collection under long-term storage conditions with low moisture contents (5±2% in hermetically closed containers at −18°C. On the basis of experimental data, the seed storage characters σ (standard deviation of seed death in storage, P50% (the time for viability to fall to 50% and P10% (the time for viability reduction of 10% were determined allowing the prediction of seed storage life and the regeneration needs. The results showed significant differences in loss of seed viability among species and within the species. After 20–24 years of storage, eleven crops showed minimal viability decline under 5% as compared to the initial viability (oats, barley, maize, bread wheat, durum wheat, smooth brome grass, faba bean, chickpea, sunflower, cucumber and pepper. For the same storage time, another group of crops (sorghum, triticale, orchard grass, tall fescue, common vetch, grass pea, lentil, common bean, rapeseed, tobacco, flax, cabbage and tomatoes presented 5–10% reduction of seed viability. More significant changes in seed viability – above 10% – were detected for peanuts, lettuce, soybean and rye. The σ values varied from 20.41 years (Arachis hypogaea L. to 500 years (for Avena sativa L. and Triticum aestivum L. There was wide variation across species, both in time taken for the viability to fall to 50% and in time taken for the seed viability reduction of 10%. The study illustrates the positive effect of both seed storability early monitoring and prediction of regeneration needs as a tool for limiting undesired losses.

  2. Composes inter-halogenes sous pression: etude des transformations structurales dans le monobromure d'iode sous forme dense

    Science.gov (United States)

    Bouchard, Alexandre

    La famille des composes halogenes et inter-halogenes representent des solides moleculaires adoptant des phases denses communes avec des solides moleculaires diatomiques comme l'azote et l'hydrogene. Parmi les transformations structurales et electroniques induites sous haute pression et observees dans ces solides, on note, entre autres, la dissociation moleculaire et la metallisation. De plus, l'etude des phases denses de l'iode a permis recemment l'observation d'une structure cristalline possedant une modulation dite incommensurable, c'est-a-dire une modulation possedant une periodicite differente de celle de la structure cristalline, jetant ainsi une lumiere nouvelle sur le processus de dissociation moleculaire dans les solides halogenes. Dans ce memoire, on propose d'etudier les changements structuraux dans monobromure d'iode (IBr), un compose inter-halogene possedant des proprietes structurales semblables a celles de deux composes halogenes, soit l'iode (I 2) et le brome (Br2) sous leur forme solide. Des experiences de diffraction des rayons X de poudres en utilisant un rayonnement synchrotron ont ete realisees a temperature ambiante sur l'IBr en variant la pression jusqu'aux environs de 60 GPa. La nature chimique particuliere du compose IBr a necessite la mise au point de techniques de chargement d'echantillon destinees a preserver l'integrite chimique de la substance utilisee. On rapporte egalement l'observation d'une phase de l'IBr presentant une modulation incommensurable. Les phases observees dans l'IBr permettent d'etablir des paralleles avec les phases denses rapportees dans I2 et Br2 par le biais d'un modele phenomenologique decrivant la sequence structurale des solides halogenes sous forme condensee.

  3. An emerging crisis across northern prairie refuges: Prevalence of invasive plants and a plan for adaptive management

    Science.gov (United States)

    Grant, T.A.; Flanders-Wanner, B.; Shaffer, T.L.; Murphy, R.K.; Knutsen, G.A.

    2009-01-01

    In the northern Great Plains, native prairies managed by the U.S. Fish and Wildlife Service (Service) can be pivotal in conservation of North America's biological diversity. From 2002 to 2006, we surveyed 7,338 belt transects to assess the general composition of mixed-grass and tallgrass prairie vegetation across five "complexes" (i.e., administrative groupings) of national wildlife refuges managed by the Service in North Dakota and South Dakota. Native grasses and forbs were common (mean frequency of occurrence 47%-54%) on two complexes but uncommon (4%-13%) on two others. Conversely, an introduced species of grass, smooth brome (Bromus inermis), accounted for 45% to 49% of vegetation on two complexes and another species, Kentucky bluegrass (Poa pratensis) accounted for 27% to 36% of the vegetation on three of the complexes. Our data confirm prior suspicions of widespread invasion by introduced species of plants on Service-owned tracts of native prairie, changes that likely stem in part from a common management history of little or no disturbance (e.g., defoliation by grazing or fire). However, variability in the degree and type of invasion among prairie tracts suggests that knowledge of underlying causes (e.g., edaphic or climatic factors, management histories) could help managers more effectively restore prairies. We describe an adaptive management approach to acquire such knowledge while progressing with restoration. More specifically, we propose to use data from inventories of plant communities on Service-owned prairies to design and implement, as experiments, optimal restoration strategies. We will then monitor these experiments and use the results to refine future strategies. This comprehensive, process-oriented approach should yield reliable and robust recommendations for restoration and maintenance of native prairies in the northern Great Plains. ??2009 by the Board of Regents of the University of Wisconsin System.

  4. Conforth Ranch Wildlife Mitigation Feasibility Study, McNary, Oregon : Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Larry; Wright, Patrick; Giger, Richard

    1991-03-01

    The 2,860-acre Conforth Ranch near Umatilla, Oregon is being considered for acquisition and management to partially mitigate wildlife losses associated with McNary Hydroelectric Project. The Habitat Evaluation Procedures (HEP) estimated that management for wildlife would result in habitat unit gains of 519 for meadowlark, 420 for quail, 431 for mallard, 466 for Canada goose, 405 for mink, 49 for downy woodpecker, 172 for yellow warbler, and 34 for spotted sandpiper. This amounts to a total combined gain of 2,495 habitat units -- a 110 percent increase over the existing values for these species combined of 2,274 habitat units. Current water delivery costs, estimated at $50,000 per year, are expected to increase to $125,000 per year. A survey of local interest indicated a majority of respondents favored the concept with a minority opposed. No contaminants that would preclude the Fish and Wildlife Service from agreeing to accept the property were identified. 21 refs., 3 figs., 5 tabs.

  5. mRNA-Seq analysis of the Pseudoperonospora cubensis transcriptome during cucumber (Cucumis sativus L. infection.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Savory

    Full Text Available Pseudoperonospora cubensis, an oomycete, is the causal agent of cucurbit downy mildew, and is responsible for significant losses on cucurbit crops worldwide. While other oomycete plant pathogens have been extensively studied at the molecular level, Ps. cubensis and the molecular basis of its interaction with cucurbit hosts has not been well examined. Here, we present the first large-scale global gene expression analysis of Ps. cubensis infection of a susceptible Cucumis sativus cultivar, 'Vlaspik', and identification of genes with putative roles in infection, growth, and pathogenicity. Using high throughput whole transcriptome sequencing, we captured differential expression of 2383 Ps. cubensis genes in sporangia and at 1, 2, 3, 4, 6, and 8 days post-inoculation (dpi. Additionally, comparison of Ps. cubensis expression profiles with expression profiles from an infection time course of the oomycete pathogen Phytophthora infestans on Solanum tuberosum revealed similarities in expression patterns of 1,576-6,806 orthologous genes suggesting a substantial degree of overlap in molecular events in virulence between the biotrophic Ps. cubensis and the hemi-biotrophic P. infestans. Co-expression analyses identified distinct modules of Ps. cubensis genes that were representative of early, intermediate, and late infection stages. Collectively, these expression data have advanced our understanding of key molecular and genetic events in the virulence of Ps. cubensis and thus, provides a foundation for identifying mechanism(s by which to engineer or effect resistance in the host.

  6. Arboreal ants use the "Velcro(R principle" to capture very large prey.

    Directory of Open Access Journals (Sweden)

    Alain Dejean

    Full Text Available Plant-ants live in a mutualistic association with host plants known as "myrmecophytes" that provide them with a nesting place and sometimes with extra-floral nectar (EFN and/or food bodies (FBs; the ants can also attend sap-sucking Hemiptera for their honeydew. In return, plant-ants, like most other arboreal ants, protect their host plants from defoliators. To satisfy their nitrogen requirements, however, some have optimized their ability to capture prey in the restricted environment represented by the crowns of trees by using elaborate hunting techniques. In this study, we investigated the predatory behavior of the ant Azteca andreae which is associated with the myrmecophyte Cecropia obtusa. We noted that up to 8350 ant workers per tree hide side-by-side beneath the leaf margins of their host plant with their mandibles open, waiting for insects to alight. The latter are immediately seized by their extremities, and then spread-eagled; nestmates are recruited to help stretch, carve up and transport prey. This group ambush hunting technique is particularly effective when the underside of the leaves is downy, as is the case for C. obtusa. In this case, the hook-shaped claws of the A. andreae workers and the velvet-like structure of the underside of the leaves combine to act like natural Velcro that is reinforced by the group ambush strategy of the workers, allowing them to capture prey of up to 13,350 times the mean weight of a single worker.

  7. Three new species of Trichoderma with hyaline ascospores from China.

    Science.gov (United States)

    Zhu, Z X; Zhuang, W Y

    2015-01-01

    Collections of Trichoderma having hyaline ascospores from different areas of China were examined. Using combined analyses of morphological data, culture characters and phylogenetic information based on rDNA sequences of partial nuc translation elongation factor 1-α encoding gene (TEF1-α) and the gene encoding the second largest nuc RNA polymerase subunit (RPB2), three new species, Trichoderma applanatum, T. oligosporum and T. sinoluteum, were discovered and are described. Trichoderma applanatum produces continuous flat to pulvinate, white to cream stromata with dense orange or pale brown ostioles, and simple acremonium-like to verticillium-like conidiophores, belongs to the Hypocreanum clade and is closely related to T. decipiens. Trichoderma oligosporum forms reddish brown stromata with a downy surface, hyaline conidia and gliocladium-like conidiophores, and is closely related to but distinct from T. crystalligenum in the Psychrophila clade. Trichoderma sinoluteum, as a member of the Polysporum clade, is characterized by pale yellow stromata, white pustulate conidiomata, pachybasium-like conidiophores, and hyaline conidia. Differences between the new species and their close relatives are discussed.

  8. Expression profiling of Cucumis sativus in response to infection by Pseudoperonospora cubensis.

    Science.gov (United States)

    Adhikari, Bishwo N; Savory, Elizabeth A; Vaillancourt, Brieanne; Childs, Kevin L; Hamilton, John P; Day, Brad; Buell, C Robin

    2012-01-01

    The oomycete pathogen, Pseudoperonospora cubensis, is the causal agent of downy mildew on cucurbits, and at present, no effective resistance to this pathogen is available in cultivated cucumber (Cucumis sativus). To better understand the host response to a virulent pathogen, we performed expression profiling throughout a time course of a compatible interaction using whole transcriptome sequencing. As described herein, we were able to detect the expression of 15,286 cucumber genes, of which 14,476 were expressed throughout the infection process from 1 day post-inoculation (dpi) to 8 dpi. A large number of genes, 1,612 to 3,286, were differentially expressed in pair-wise comparisons between time points. We observed the rapid induction of key defense related genes, including catalases, chitinases, lipoxygenases, peroxidases, and protease inhibitors within 1 dpi, suggesting detection of the pathogen by the host. Co-expression network analyses revealed transcriptional networks with distinct patterns of expression including down-regulation at 2 dpi of known defense response genes suggesting coordinated suppression of host responses by the pathogen. Comparative analyses of cucumber gene expression patterns with that of orthologous Arabidopsis thaliana genes following challenge with Hyaloperonospora arabidopsidis revealed correlated expression patterns of single copy orthologs suggesting that these two dicot hosts have similar transcriptional responses to related pathogens. In total, the work described herein presents an in-depth analysis of the interplay between host susceptibility and pathogen virulence in an agriculturally important pathosystem.

  9. 加乐多土壤调理剂在瓜类蔬菜连作地上的应用效果%Application Effects of a Soil Conditioner Jialeduo on Continuous Cropping Fields of Melon Vegetables

    Institute of Scientific and Technical Information of China (English)

    史雨生

    2013-01-01

    In order to control continuous cropping obstacles in melon vegetables fields, we studied the application effects of the soil conditioner Jialeduo. The results showed that, after being applied with Jialeduo, the plants of bottle gourd grew vigorously, and had more branches, in addition, the yield was increased by 233.8 kg/667 m2 with the yield-increasing rate of 12%, and the income was increased by 1 636.6 Yuan/667 m2. Moreover, applying with Jialeduo increased the soil pH value and enhanced the flooding tolerance and resistance to downy mildew and grey mould of bottle gourd plants.%为改善瓜类蔬菜种植地连作障碍,探讨了土壤调理剂加乐多的应用效果。试验结果表明,与未施加乐多的处理相比,施用加乐多后,瓠子植株长势旺盛,分枝多,产量增加233.8 kg/667 m2,增产12%,增收1636.6元/667 m2;且提高了土壤 pH 值,增强了瓠子的耐涝性和抗霜霉病和灰霉病的能力。

  10. Control of Plant Diseases by Extracts of Inula viscosa.

    Science.gov (United States)

    Wang, Wenqiao; Ben-Daniel, B H; Cohen, Yigal

    2004-10-01

    ABSTRACT Leaves of Inula viscosa were collected from the field, dried, and extracted with a mixture of acetone and n-hexane. The oily, water-insoluble pastes obtained after evaporation of the solvents were used for the control of foliar diseases in growth chambers. The pastes, either dissolved in acetone or emulsified in water, effectively controlled downy mildew of cucumber, late blight of potato or tomato, powdery mildew of wheat, and rust of sunflower. Mean effective dose (concentration) required for 90% inhibition of disease values for acetone solutions and water emulsions ranged from 0.68 to 1.02% and 0.65 to 1.00% (wt/vol), respectively. Dry matter content in fresh leaves, paste-extract yield in dry leaves, and disease control efficacy of paste extracts were similar in leaves of I. viscosa collected during May to October, suggesting that, for practical use, harvests can be conducted during most of the growing season. The results show that I. viscosa may be used as an herbal source for fungicidal preparations against foliar diseases caused by pathogens belonging to the families Oomycetes, Ascomycetes, and Basidiomycetes.

  11. Identification and characterisation of Dof transcription factors in the cucumber genome.

    Science.gov (United States)

    Wen, Chang-Long; Cheng, Qing; Zhao, Liqun; Mao, Aijun; Yang, Jingjing; Yu, Shuancang; Weng, Yiqun; Xu, Yong

    2016-03-16

    Cucumber is vulnerable to many foliage diseases. Recent studies reported cloning of candidate genes for several diseases in cucumber; however, the exact defence mechanisms remain unclear. Dof genes have been shown to play significant roles in plant growth, development, and responses to biotic and abiotic stresses. Dof genes coding for plant-specific transcription factors can promote large-scale expression of defence-related genes at whole genome level. The genes in the family have been identified and characterized in several plant species, but not in cucumber. In the present study, we identified 36 CsDof members from the cucumber draft genomes which could be classified into eight groups. The proportions of the CsDof family genes, duplication events, chromosomal locations, cis-elements and miRNA target sites were comprehensively investigated. Consequently, we analysed the expression patterns of CsDof genes in specific tissues and their response to two biotic stresses (watermelon mosaic virus and downy mildew). These results indicated that CsDof may be involved in resistance to biotic stresses in cucumber.

  12. Revisiting Vitis vinifera subtilase gene family: a possible role in grapevine resistance against Plasmopara viticola

    Directory of Open Access Journals (Sweden)

    Joana Figueiredo

    2016-11-01

    Full Text Available Subtilisin-like proteases, also known as subtilases, are a very diverse family of serine peptidases present in many organisms. In grapevine, there are hints of the involvement of subtilases in defence mechanisms, but their role is not yet understood. The first characterization of the subtilase gene family was performed in 2014. However, simultaneously, the grapevine genome was re-annotated and several sequences were re-annotated or retrieved. We have performed a re-characterization of this family in grapevine and identified 82 genes coding for 97 putative proteins, as result of alternative splicing. All the subtilases identified present the characteristic S8 peptidase domain and the majority of them also have a pro-domain I9 inhibitor, a protease-associated (PA domain and a signal peptide for targeting to the secretory pathway. Phylogenetic studies revealed six subtilase groups denominated VvSBT1 to VvSBT6. As several evidences have highlighted the participation of plant subtilases in response to biotic stimulus, we have investigated subtilase participation in grapevine resistance to Plasmopara viticola, the causative agent of downy mildew. Fourteen grapevine subtilases presenting either high homology to P69C from tomato, SBT3.3 from Arabidopsis thaliana or located near the Resistance to Plasmopara viticola (RPV locus were selected. Expression studies were conducted in the grapevine-P. viticola pathosystem with resistant and susceptible cultivars. Our results may indicate that some of grapevine subtilisins are potentially participating in the defence response against this biotrophic oomycete.

  13. Rin4 Causes Hybrid Necrosis and Race-Specific Resistance in an Interspecific Lettuce Hybrid[W

    Science.gov (United States)

    Jeuken, Marieke J.W.; Zhang, Ningwen W.; McHale, Leah K.; Pelgrom, Koen; den Boer, Erik; Lindhout, Pim; Michelmore, Richard W.; Visser, Richard G.F.; Niks, Rients E.

    2009-01-01

    Some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. Hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. We observed hybrid necrosis in interspecific lettuce (Lactuca sativa and Lactuca saligna) hybrids that correlated with resistance to downy mildew. Segregation analysis revealed a specific allelic combination at two interacting loci to be responsible. The allelic interaction had two consequences: (1) a quantitative temperature-dependent autoimmunity reaction leading to necrotic lesions, lethality, and quantitative resistance to an otherwise virulent race of Bremia lactucae; and (2) a qualitative temperature-independent race-specific resistance to an avirulent race of B. lactucae. We demonstrated by transient expression and silencing experiments that one of the two interacting genes was Rin4. In Arabidopsis thaliana, RIN4 is known to interact with multiple R gene products, and their interactions result in hypersensitive resistance to Pseudomonas syringae. Site-directed mutation studies on the necrosis-eliciting allele of Rin4 in lettuce showed that three residues were critical for hybrid necrosis. PMID:19855048

  14. Cloning and expression of sesquiterpene synthase genes from lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Bennett, Mark H; Mansfield, John W; Lewis, Mervyn J; Beale, Michael H

    2002-06-01

    Sesquiterpenoid lactones (SLs) from lettuce (Lactuca sativa L.) include constitutive components of latex such as lactucin and the induced phytoalexin, lettucenin A. A redundant primer strategy was used to recover two full length cDNA clones (LTC1 and LTC2) encoding sesquiterpene synthases from a cDNA library derived from seedlings with the red spot disorder, which accumulate phytoalexins. Recombinant enzymes produced from LTC1 and LTC2 in Escherichia coli catalysed the cyclisation of farnesyl diphosphate to germacrene A, potentially an early step in the biosynthesis of SLs. RT-PCR analysis showed LTC1 and LTC2 were expressed constitutively in roots, hypocotyls and true leaves but not in cotyledons. Expression in cotyledons was induced by challenge with the downy mildew pathogen Bremia lactucae in the disease resistant cultivar Diana. Southern hybridisation experiments showed that LTC1 and LTC2 were not part of a multigene family. The germacrene A synthases provide targets for modified expression to generate beneficial modifications to the SL profile in lettuce.

  15. Rin4 causes hybrid necrosis and race-specific resistance in an interspecific lettuce hybrid.

    Science.gov (United States)

    Jeuken, Marieke J W; Zhang, Ningwen W; McHale, Leah K; Pelgrom, Koen; den Boer, Erik; Lindhout, Pim; Michelmore, Richard W; Visser, Richard G F; Niks, Rients E

    2009-10-01

    Some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. Hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. We observed hybrid necrosis in interspecific lettuce (Lactuca sativa and Lactuca saligna) hybrids that correlated with resistance to downy mildew. Segregation analysis revealed a specific allelic combination at two interacting loci to be responsible. The allelic interaction had two consequences: (1) a quantitative temperature-dependent autoimmunity reaction leading to necrotic lesions, lethality, and quantitative resistance to an otherwise virulent race of Bremia lactucae; and (2) a qualitative temperature-independent race-specific resistance to an avirulent race of B. lactucae. We demonstrated by transient expression and silencing experiments that one of the two interacting genes was Rin4. In Arabidopsis thaliana, RIN4 is known to interact with multiple R gene products, and their interactions result in hypersensitive resistance to Pseudomonas syringae. Site-directed mutation studies on the necrosis-eliciting allele of Rin4 in lettuce showed that three residues were critical for hybrid necrosis.

  16. Pathogenic variation and sexual reproduction in Swedish populations of Bremia lactucae.

    Science.gov (United States)

    Gustafsson, M; Liljeroth, E; Gustafsson, I

    1985-09-01

    The host-pathogen interaction between lettuce (Lactuca sativa) and downy mildew (Bremia lactucae) is mainly differential and the resistance so far utilized in the host is vertical. As in many other obligate parasites, the introduction of cultivars with new vertical resistance has exerted a strong selection pressure on the pathogen resulting in significant changes in virulence frequencies and in the establishment of races with new combinations of virulence. Genetic diversity in pathogen populations may arise through mutation and gene flow, and new virulence genotypes may then be established through parasexuality and sexual recombination. In Swedish populations of Bremia lactucae, the pattern of variation in the parasite agrees well with that which might be expected in a diploid, outcrossing organism with frequent sexual reproduction. This is supported by: two or more isolates, different in virulence and mating type, may occur together on the same lettuce leaf; zygotes (oospores) are formed in all populations investigated and the frequency varies from 22% to 98%; oospores germinate rather frequently under suitable conditions. To breed for resistance in dynamic host-pathogen systems such as this one is difficult and the program should preferably be based on race-non-specific resistance.

  17. Videographic evidence of endangered species depredation by feral cat

    Science.gov (United States)

    Judge, Seth; Lippert, Jill S.; Misajon, Kathleen; Hu, Darcy; Hess, Steven C.

    2012-01-01

    Feral cats (Felis cafus) have long been implicated as nest predators of endangered 'Ua'u (Hawaiian Petrel; Pterodroma sandwichensis) on Hawaii Island, but until recently, visual confirmation has been limited by available technology. 'Ua'u nest out of view, deep inside small cavities, on alpine lava flows. During the breeding seasons of 2007 and 2008, we monitored known burrows within Hawai'i Volcanoes National Park. Digital infrared video cameras assisted in determining the breeding behaviour and nesting success at the most isolated of burrows. With 7 cameras, we collected a total of 819 videos and 89 still photographs of adult and nestling 'Ua'u at 14 burrows. Videos also confirmed the presence of rats (Rattus spp.) at 2 burrows, 'Ōmao (Myadestes obscurus) at 8 burrows, and feral cats at 6 burrows. A sequence of videos showed a feral cat taking a downy 'Ua'u chick from its burrow, representing the first direct evidence of 'Ua'u depredation by feral cat in Hawai'i. This technique provides greater understanding of feral cat behaviour in 'Ua'u colonies, which may assist in the development of more targeted management strategies to reduce nest predation on endangered insular bird species.

  18. Highly abundant and stage-specific mRNAs in the obligate pathogen Bremia lactucae.

    Science.gov (United States)

    Judelson, H S; Michelmore, R W

    1990-01-01

    Germinating spores of the obligate pathogen Bremia lactucae (lettuce downy mildew) contain several unusually abundant species of mRNA. Thirty-nine cDNA clones corresponding to prevalent transcripts were isolated from a library synthesized using poly(A)+ RNA from germinating spores; these clones represented only five distinct classes. Each corresponding mRNA accounted for from 0.4 to 9 percent by mass of poly(A)+ RNA from germinating spores and together represented greater than 20 percent of the mRNA. The expression of the corresponding genes, and a gene encoding Hsp70, was analyzed in spores during germination and during growth in planta. The Hsp70 mRNA and mRNA from one abundant cDNA clone (ham34) were expressed constitutively. Two clones (ham9 and ham12) hybridized only to mRNA from spores and germinating spores. Two clones (ham37 and ham27) showed hybridization specific to germinating spores. Quantification of the number of genes homologous to each cDNA clone indicated that four clones corresponded to one or two copies per haploid genome, and one hybridized to an approximately 11-member family of genes. A sequence of the gene corresponding to ham34 was obtained to investigate its function and to identify sequences conferring high levels of gene expression for use in constructing vectors for the transformation of B. lactucae.

  19. Genetic analysis of the fungus, Bremia lactucae, using restriction fragment length polymorphisms.

    Science.gov (United States)

    Hulbert, S H; Ilott, T W; Legg, E J; Lincoln, S E; Lander, E S; Michelmore, R W

    1988-12-01

    Restriction fragment length polymorphisms (RFLPs) were developed as genetic markers for Bremia lactucae, the biotrophic Oomycete fungus which causes lettuce downy mildew. By using 55 genomic and cDNA probes, a total of 61 RFLP loci were identified among three heterothallic isolates of B. lactucae. Of these 61 RFLP loci, 53 were heterozygous in at least one of the three strains and thus were informative for linkage analysis in at least one of two F1 crosses that were performed. Analysis of the cosegregation of these 53 RFLPs, eight avirulence loci and the mating type locus allowed the construction of a preliminary genetic linkage map consisting of 13 small linkage groups. Based on the extent of linkage detected among probes, the genome of B. lactucae can be estimated to be approximately 2000 cM. Linkage was detected between a RFLP locus and an avirulence gene, providing a potential starting point for chromosome walking to clone an avirulence gene. The high frequency of DNA polymorphism in naturally occurring isolates and the proper Mendelian segregation of loci detected by low copy number probes indicates that it will be possible to construct a detailed genetic map of B. lactucae using RFLPs as markers. The method of analysis employed here should be applicable to many other outbreeding, heterozygous species for which defined inbred lines are not available.

  20. The feather mites of the hoatzin Opisthocomus hoazin (Müller) (Aves: Opisthocomiformes), with the description of two new genera and six new species (Acari: Analgoidea, Pterolichoidea).

    Science.gov (United States)

    Hernandes, Fabio A; Mironov, Sergey V

    2015-10-30

    Six new species and two new genera of feather mites are described from the hoatzin Opisthocomus hoazin (Müller) (Opisthocomiformes: Opisthocomidae) in Brazil: Gymnolichus lacrimosus sp. n., G. latihumeralis sp. n. (Xolalgidae), Temnalges hoazin sp. n., T. atelodiscus sp. n. (Psoroptoididae), Ciganalichus boasfilhoi gen. n., sp. n., and Hoazinacarus anisosetus gen. n., sp. n. (Pterolichidae). Illustrations of two previously known species, Opisthocomacarus umbellifer (Trouessart, 1899) and Stakyonemus hystrix (Trouessart, 1899) are provided. We show that the hoatzin bears a much richer feather mite fauna than previously thought and presently includes eight mite species from three families: Xolalgidae, Psoroptoididae (Analgoidea) and Pterolichidae (Pterolichoidea). They represent two morpho-ecological groups: (1) mites inhabiting the wing and tail feathers, and (2) mites living in downy and body contour feathers. We hypothesize that these mites represent a native feather mite fauna of the hoatzin, inherited from its ancestors and existing on this bird for a long time. The controversial and unresolved relationships of this bird with other bird taxa are briefly discussed in the light of the new acarofauna discovered.

  1. Dynamic vortex interactions with flexible fibers and edges for prediction of owl noise suppression

    Science.gov (United States)

    Korykora, Sarah; Jaworski, Justin

    2015-11-01

    The compliant trailing-edge fringe of owls and the soft downy material on their upper wing surfaces are thought to enable their silent flight by weakening the interaction of boundary layer turbulence with these flexible structures. Previous analysis of turbulence noise generation by wave-bearing elastic edges have shown that the far-field acoustic power scaling can be weakened by up to the square of the Mach number relative to a rigid edge. However, it is unclear whether or not the wave-bearing feature or simply the flexible nature of the edge scatterer produces this noise suppression. To assess this distinction, a dynamic vortex interaction model is developed whereby the motion of a line vortex round a rigid but elastically-restrained wall-mounted fiber or trailing edge is determined numerically. Special attention is paid to the dynamic interaction between the flexible structure and vortex, which is accomplished via a conformal mapping relationship determined in closed form. Results from this analysis seek to develop a vortex sound model to discern the effect of flexible versus wave-bearing scatterers on turbulence noise suppression and help explain the mechanisms of silent owl flight.

  2. Conversion trials in mixed coppices of Gargano (Puglia, Italy: first results

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Six plots have been drawn in an mixed aged coppice stand, 40 years after last coppicing; they represent a typical expression of Doronico-Carpinetum phytosociological association and they are characteristic of many woods of Gargano’s territory, composed by Quercus cerris L. (turkey oak, Quercus pubescens Willd. (downy oak, Acer opalus Mill. (italian maple, Carpinus betulus L. (european hornbeam, Ostrya carpinifolia Scop. (hop hornbeam. Compared treatments are: natural evolution of the coppice without thinning versus two thinning regimes with different intensity, both aimed to convert the stands into high forests. 1200 and 1600 stems per hectare were released in the conversion plots. Plots, control and treated in 2001, have been measured before and immediately after thinning and remeasured five years later. At the present time, stands are characterized by a basically monolayered structure, in which turkey oak is prevalent in term of basal area. Moreover in thinned areas, losses on the released shoots number are unimportant both in absolute and in percent terms; in control plot, instead, competition by plants of upper storey on the dominated ones means high values of mortality.

  3. Evaluating electrolysed oxidising water as a fungicide using two rose varieties (Rosa sp in greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Belén Rocío Fernández

    2011-05-01

    Full Text Available The aim of evaluating electrolysed oxidising water (EOWfor controlling botrytis (Botrytis cinerea, powdery mildew(Sphaerotheca pannosa and downy mildew (Peronosporasparsa using two greenhouse rose varieties was to verifythis new technology’s effectiveness by contrast with traditionalchemical handling. Two concentrations of hypochlorousacid in EOW were produced during electrolysisin aP1200 cell and applied at three application volumesusing stationary hydraulic pressure equipment. Thecommercial rose varieties (Rosa sp used here were theOrlando and Versilia varieties. The EOW used was slightlyacidic type C, pH 5.0, having high-oxide-reduction potential(ORP +850 millivolts (mV. Two types of EOWwere evaluated for this study: EOW C-50 (50 ppm HOCland EOW C-75 (75 ppm HOCl. The test results showedthe feasibility of EOW as a fungicide at the volumes testedhere, providing significant control of powdery mildewwhich has high incidence due to climatic conditions. Thebest disease control was achieved by applying the highestvolume; however, some curled leaflets appeared with thisapplication.

  4. Direct Effects of Carpophagous Insects on the Germination Ability and Early Abscission of Oak Acorns

    Directory of Open Access Journals (Sweden)

    CSÓKA, György

    2006-01-01

    Full Text Available Carpophagous insects play an important role in decreasing the viability of acorns in bothdirect and indirect ways. Therefore they significantly influence the reproductive potential of oaks. As adirect effect, their feeding on the embryo and on the cotyledons may prevent the germination of theacorn and on the other hand, their damage causes premature acorn abscission. During 3 years, 60acorn samples from five oak species (Turkey oak – Quercus cerris, pedunculate oak – Quercus robur,sessile oak – Quercus petraea, downy oak – Quercus pubescens, red oak – Quercus rubra have beeninvestigated. The average rate of damage varied a lot between years, but was always significant (2000:36%, 2001: 61%, 2002: 51%. The insects’ influence causing premature acorn abscission wassignificant both for pedunculate and Turkey oaks. The premature acorn abscission was 34% of thetotal crop in 2000 for pedunculate oak (Curculio spp. 26%, Cydia spp. 2% and Andricusquercuscalicis 6% and 39% in 2001 (Curculio spp. 14%, Cydia spp. 2%, Andricus quercuscalicis13%, Callirhytis glandium 10%. In case of Turkey oak it was 29% in 2001 (C. glandium 16%,Neuroterus saliens 13%, and 12% in 2002 (C. glandium 10%, N. saliens 2%.

  5. Phytochemical screening and In vitro antioxidant activity of Paracalyx scariosa (Roxb Ali

    Directory of Open Access Journals (Sweden)

    RAMOJI ALLA

    2014-06-01

    Full Text Available Paracalyx scariosa (Roxb. Ali. also called as Paracalyx scariosus and cylista scariosa is a woody twiners belongs to the family Fabaceae is one of the important medicinal plant distributed in Central Provinces, West and South India, and Upper Burma. It is woody twiners with tomentose branches and stems finely downy. Leaves are 3-foliate with rhachis prolonged 6-13mm. between the insertion of the leaflets and stipels of the terminal one. The objective of this study is to explore the phytochemistry and the antioxidant potential of various extracts of Paracalyx scariosa (Roxb. Ali which is considered traditionally as an important medicinal plant. The preliminary phytochemical analysis was done to find out the presence of various bioactive compounds and TLC was performed to identify the no of flavonoids present. In vitro antioxidant analysis of methanol, acetone, benzene extracts and ethyl acetate , aqueous fractions of methanol extract was carried out by DPPH assay and Nitric oxide assay. It is observed from the phytochemical study, carbohydrates, proteins, saponins, triterpenoids, flavonoids and alkaloids are present in all the three extracts and Ethyl acetate fraction, benzene extract were separated in to 5 spots identified by bluish black colour confirming the presence of 5 types of flavonoids and the Acetone extract was not separated. Besides the extracts and fractions also possess strong antioxidant activity

  6. Combating plant diseases--the Darwin connection.

    Science.gov (United States)

    Hollomon, Derek W; Brent, Keith J

    2009-11-01

    Although Darwin knew of plant diseases, he did not study them as part of his analysis of natural selection. Effective plant disease control has only been developed after his death. This article explores the relevance of Darwin's ideas to three problem areas with respect to diseases caused by fungi: emergence of new diseases, loss of disease resistance bred into plants and development of fungicide resistance. Darwin's concept of change through natural or artificial selection relied on selection of many small changes, but subsequent genetic research has shown that change can also occur through large steps. Appearance of new diseases can involve gene duplication, transfer or recombination, but all evidence points to both host plant resistance and fungicide susceptibility being overcome through point mutations. Because the population size of diseases such as rusts and powdery and downy mildews is so large, all possible point mutations are likely to occur daily, even during moderate epidemics. Overcoming control measures therefore reflects the overall fitness of these mutants, and much resource effort is being directed towards assessment of their fitness, both in the presence and in the absence of selection. While recent developments in comparative genomics have caused some revision of Darwin's ideas, experience in managing plant disease control measures clearly demonstrates the relevance of concepts he introduced 150 years ago. It also reveals the remarkable speed and the practical impact of adaptation in wild microorganism populations to changes in their environment, and the difficulty of stopping or delaying such adaptation.

  7. Ammonium carbonate is more attractive than apple and hawthorn fruit volatile lures to Rhagoletis pomonella (Diptera: Tephritidae) in Washington State.

    Science.gov (United States)

    Yee, Wee L; Nash, Meralee J; Goughnour, Robert B; Cha, Dong H; Linn, Charles E; Feder, Jeffrey L

    2014-08-01

    The apple maggot fly, Rhagoletis pomonella (Walsh), is an introduced, quarantine pest of apple (Malus domestica Borkhausen) in the Pacific Northwest of the United States. In the eastern United States where the fly is native, fruit volatiles have been reported to be more attractive than ammonia compounds to R. pomonella. However, the opposite may be true in the western United States. Here, we determined whether newly identified western apple and western hawthorn fruit volatiles are more attractive than ammonium carbonate (AC) to R. pomonella in apple, black hawthorn, and ornamental hawthorn trees in western Washington State. In all three host trees, sticky red sphere or yellow panel traps baited with AC generally caught more flies than traps baited with lures containing the four newly developed fruit blends (modified eastern apple, western apple, western ornamental hawthorn, and western black hawthorn) or two older blends (eastern apple and eastern downy hawthorn). Fruit volatiles also displayed more variation among trapping studies conducted at different sites, in different host trees, and across years than AC. The results imply that traps baited with AC represent the best approach to monitoring R. pomonella in Washington State.

  8. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    Science.gov (United States)

    Pessanha, Sofia; Carvalho, Maria Luisa; Becker, Maria; von Bohlen, Alex

    2010-06-01

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  9. Expression profiling of Cucumis sativus in response to infection by Pseudoperonospora cubensis.

    Directory of Open Access Journals (Sweden)

    Bishwo N Adhikari

    Full Text Available The oomycete pathogen, Pseudoperonospora cubensis, is the causal agent of downy mildew on cucurbits, and at present, no effective resistance to this pathogen is available in cultivated cucumber (Cucumis sativus. To better understand the host response to a virulent pathogen, we performed expression profiling throughout a time course of a compatible interaction using whole transcriptome sequencing. As described herein, we were able to detect the expression of 15,286 cucumber genes, of which 14,476 were expressed throughout the infection process from 1 day post-inoculation (dpi to 8 dpi. A large number of genes, 1,612 to 3,286, were differentially expressed in pair-wise comparisons between time points. We observed the rapid induction of key defense related genes, including catalases, chitinases, lipoxygenases, peroxidases, and protease inhibitors within 1 dpi, suggesting detection of the pathogen by the host. Co-expression network analyses revealed transcriptional networks with distinct patterns of expression including down-regulation at 2 dpi of known defense response genes suggesting coordinated suppression of host responses by the pathogen. Comparative analyses of cucumber gene expression patterns with that of orthologous Arabidopsis thaliana genes following challenge with Hyaloperonospora arabidopsidis revealed correlated expression patterns of single copy orthologs suggesting that these two dicot hosts have similar transcriptional responses to related pathogens. In total, the work described herein presents an in-depth analysis of the interplay between host susceptibility and pathogen virulence in an agriculturally important pathosystem.

  10. Proteomic Analysis of Cucumber Defense Rresponses Induced by Propamocarb

    Institute of Scientific and Technical Information of China (English)

    WU Peng; QIN Zhi-wei; WU Tao; ZHOU Xiu-yan; XIN Ming; GUO Qian-qian

    2013-01-01

    Propamocarb is an agricultural chemical that has been widely used to protect cucumber plants from downy mildew. To understand the mechanisms of cucumber defense responses to propamocarb, we investigated the physiological and proteomic responses of the cucumber line D0351 with propamocarb application. We found that after treatment with propamocarb, the activities of detoxifying enzymes (glutathione reductase, GR; glutathione S-tramsferase, GST) and soluble sugar content of cucumber fruit were signiifcantly increased, but malonaldehyde (MDA) content was signiifcantly reduced. To identify components of propamocarb responsive signaling, we compared the high resolution two-dimensional gel electrophoresis (2-DE) protein proifles of control and propamocarb-treated fruits, and identiifed 18 differentially expressed (13 up-regulated and 5 down-regulated) proteins induced by propamocarb which were determined by matrix-assisted laser desorption/ionization time-of-lfight mass spectrometry (MALDI-TOF-MS). The majority of the proteins had functions related to detoxication, energy and transport, protein biosynthesis, regulating reactions and defending against stresses. A real-time quantitative reverse transcriptional-polymerase chain reaction (qRT-PCR) was used to compare transcript and protein accumulation patterns for 18 candidate proteins, and the expression of 14 was consistent at both transcript and protein levels. The responses of cucumber proteome to propamocarb seemed complex; the identified proteins may play an important role in regulating adaptation activities following exposure to propamocarb. Data presented herein may shed light on understanding cucumber fruit defense responses under propamocarb treatment.

  11. [An orientational examination of the effects of extracts from mixtures of herbal drugs on selected renal functions].

    Science.gov (United States)

    Masteiková, R; Klimas, R; Samura, B B; Savickas, A; Samura, B A; Belaij, S I; Samura, I B; Rabisková, M; Chalupová, Z; Bernatoniene, J

    2007-04-01

    The paper aimed to determine the effects of mixtures of selected medicinal plants on some physiological renal functions, i.e. excretion of urine and electrolytes and changes in the quantity of prostaglandins E2 (PGE2) and kallikrein-kinins in rat blood plasma after water and salt load. The following medicinal plants were selected for the examination: downy birch (Betula pubescens EHRH.), everlasting flower (Helichrysum arenarium L. MOENCH.), hawthorn (Crataegus oxyacantha L.), woodland strawberry (Fragaria vesca L.), sweet corn (Zea mays L.), German chamomile (Matricaria recutita L.), and field horsetail (Equisetum arvense L.). Herbal drugs were used to compose 6 mixtures. Extracts from these mixtures were administered to Wistar strain males and their effects were compared with the effects of an administered suspension of hydrochlorothiazide, an extract from field horsetail herb alone, and a control group of animals which was not administered any preparation. The greatest diuretic effect was found in a mixture composed of birch leaves (Betulae folium), hawthorn berries (Crataegi fructus), strawberry leaves (Fragariae folium), corn silk (Maydis stigmata), chamomile flowers (Matricariae flos), and horsetail herb (Equiseti herba). Its effect was greater by 47% and 34% than the effect of a horsetail herb extract and a hydrochlorothiazide suspension (p < 0.05), respectively. The extract from this mixture also increased the quantity of prostaglandins E2 and kallikrein-kinins in rat blood plasma in water and salt load.

  12. Triboelectric Nanogenerator Enabled Body Sensor Network for Self-Powered Human Heart-Rate Monitoring.

    Science.gov (United States)

    Lin, Zhiming; Chen, Jun; Li, Xiaoshi; Zhou, Zhihao; Meng, Keyu; Wei, Wei; Yang, Jin; Wang, Zhong Lin

    2017-09-26

    Heart-rate monitoring plays a critical role in personal healthcare management. A low-cost, noninvasive, and user-friendly heart-rate monitoring system is highly desirable. Here, a self-powered wireless body sensor network (BSN) system is developed for heart-rate monitoring via integration of a downy-structure-based triboelectric nanogenerator (D-TENG), a power management circuit, a heart-rate sensor, a signal processing unit, and Bluetooth module for wireless data transmission. By converting the inertia energy of human walking into electric power, a maximum power of 2.28 mW with total conversion efficiency of 57.9% was delivered at low operation frequency, which is capable of immediately and sustainably driving the highly integrated BSN system. The acquired heart-rate signal by the sensor would be processed in the signal process circuit, sent to an external device via the Bluetooth module, and displayed on a personal cell phone in a real-time manner. Moreover, by combining a TENG-based generator and a TENG-based sensor, an all-TENG-based wireless BSN system was developed, realizing continuous and self-powered heart-rate monitoring. This work presents a potential method for personal heart-rate monitoring, featured as being self-powered, cost-effective, noninvasive, and user-friendly.

  13. Morphological and genetic identification and isotopic study of the hair of a cave lion (Panthera spelaea Goldfuss, 1810) from the Malyi Anyui River (Chukotka, Russia)

    Science.gov (United States)

    Chernova, O. F.; Kirillova, I. V.; Shapiro, B.; Shidlovskiy, F. K.; Soares, A. E. R.; Levchenko, V. A.; Bertuch, F.

    2016-06-01

    We present the first detailed analyses of the preserved hair of a cave lion (Panthera spelaea Goldfuss, 1810). The hair was found in association with a skeleton that was recovered recently from perennially frozen Pleistocene sediments in the lower reaches of the Malyi Anyui River (Chukotka, Russia). We extract mitochondrial DNA from the hair to confirm its taxonomic identity, and perform detailed morphological analyses of the color and structure of the hair using light optical microscopy and SEM. In addition, we compare the cave lion hair to hair taken from the back and mane of an African lion. We find that cave lion hair is similar but not identical to that of the present-day lion. In addition to slightly different coloration, cave lions had a very thick and dense undercoat comprising closed and compressed wavy downy hair with a medulla. In addition, while the microstructures of the medulla and cortex of cave lion hair are similar in extinct and living lions, the cuticular scales of cave lion hair are higher than those in living lions, suggesting that cave lion hair is stronger and more robust than that of living lions. We hypothesize that the differences between cave lion hair and present-day lion hair may be due to adaptations of cave lions to the harsh climatic and environmental conditions of the Pleistocene Ice Ages.

  14. Pesticides' influence on wine fermentation.

    Science.gov (United States)

    Caboni, Pierluigi; Cabras, Paolo

    2010-01-01

    Wine quality strongly depends on the grape quality. To obtain high-quality wines, it is necessary to process healthy grapes at the correct ripeness stage and for this reason the farmer has to be especially careful in the prevention of parasite attacks on the grapevine. The most common fungal diseases affecting grape quality are downy and powdery mildew (Plasmopara viticola and Uncinula necator), and gray mold (Botrytis cinerea). On the other hand, the most dangerous insects are the grape moth (Lobesia botrana), vine mealybug (Planococcus ficus), and the citrus mealybug (Planococcus citri). Farmers fight grape diseases and insects applying pesticides that can be found at harvest time on grapes. The persistence of pesticides depends on the chemical characteristic of the active ingredients as well as on photodegradation, thermodegradation, codistillation, and enzymatic degradation. The pesticide residues on grapes can be transferred to the must and this can influence the selection and development of yeast strains. Moreover, yeasts can also influence the levels of the pesticides in the wine by reducing or adsorbing them on lees. During the fermentative process, yeasts can cause the disappearance of pesticide residues by degradation or absorption at the end of the fermentation when yeasts are deposited as lees. In this chapter, we reviewed the effect of commonly used herbicides, insecticides, and fungicides on yeasts. We also studied the effect of alcoholic and malolactic fermentation on pesticide residues.

  15. Influence of Nitrogen Availability on Growth of Two Transgenic Birch Species Carrying the Pine GS1a Gene

    Directory of Open Access Journals (Sweden)

    Vadim G. Lebedev

    2017-01-01

    Full Text Available An alternative way to increase plant productivity through the use of nitrogen fertilizers is to improve the efficiency of nitrogen utilization via genetic engineering. The effects of overexpression of pine glutamine synthetase (GS gene and nitrogen availability on growth and leaf pigment levels of two Betula species were studied. Untransformed and transgenic plants of downy birch (B. pubescens and silver birch (B. pendula were grown under open-air conditions at three nitrogen regimes (0, 1, or 10 mM for one growing season. The transfer of the GS1a gene led to a significant increase in the height of only two transgenic lines of nine B. pubescens, but three of five B. pendula transgenic lines were higher than the controls. In general, nitrogen supply reduced the positive effect of the GS gene on the growth of transgenic birch plants. No differences in leaf pigment levels between control and transgenic plants were found. Nitrogen fertilization increased leaf chlorophyll content in untransformed plants but its effect on most of the transgenic lines was insignificant. The results suggest that birch plants carrying the GS gene use nitrogen more efficiently, especially when growing in nitrogen deficient soil. Transgenic lines were less responsive to nitrogen supply in comparison to wild-type plants.

  16. Transfer of elements relevant to nuclear fuel cycle from soil to boreal plants and animals in experimental meso- and microcosms.

    Science.gov (United States)

    Tuovinen, Tiina S; Kasurinen, Anne; Häikiö, Elina; Tervahauta, Arja; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka

    2016-01-01

    Uranium (U), cobalt (Co), molybdenum (Mo), nickel (Ni), lead (Pb), thorium (Th) and zinc (Zn) occur naturally in soil but their radioactive isotopes can also be released into the environment during the nuclear fuel cycle. The transfer of these elements was studied in three different trophic levels in experimental mesocosms containing downy birch (Betula pubescens), narrow buckler fern (Dryopteris carthusiana) and Scandinavian small-reed (Calamagrostis purpurea ssp. Phragmitoides) as producers, snails (Arianta arbostorum) as herbivores, and earthworms (Lumbricus terrestris) as decomposers. To determine more precisely whether the element uptake of snails is mainly via their food (birch leaves) or both via soil and food, a separate microcosm experiment was also performed. The element uptake of snails did not generally depend on the presence of soil, indicating that the main uptake route was food, except for U, where soil contact was important for uptake when soil U concentration was high. Transfer of elements from soil to plants was not linear, i.e. it was not correctly described by constant concentration ratios (CR) commonly applied in radioecological modeling. Similar nonlinear transfer was found for the invertebrate animals included in this study: elements other than U were taken up more efficiently when element concentration in soil or food was low.

  17. Manejo da adubação potássica e da irrigação no progresso de doenças fúngicas e produtividade da melancia Potassium fertilizer and irrigation management in the progress of fungal diseases and yield of watermelon

    Directory of Open Access Journals (Sweden)

    Gil R dos Santos

    2013-03-01

    Full Text Available Entre as principais doenças da melancia, o crestamento gomoso do caule (Didymella bryoniae e o míldio (Pseudoperonospora cubensis se destacam devido às grandes perdas que causam na produtividade e qualidade de frutos. Para investigar a influência da adubação potássica no progresso do crestamento gomoso e na produtividade da melancia e a influência da lâmina de água e do intervalo de irrigação no progresso do míldio, foram conduzidos dois ensaios em condições de campo em Gurupi-TO, nos anos de 2009 e 2010. O ensaio I foi conduzido em blocos ao acaso e os tratamentos se constituíram em três doses de potássio aplicadas em cobertura (0, 50 e 100 kg ha-1 de KCl e 12 repetições, sendo avaliada a severidade do crestamento gomoso, por meio de uma escala de notas e os dados de produção e qualidade dos frutos. No ensaio II, utilizou-se o delineamento em blocos ao acaso com quatro repetições, em esquema fatorial de 3 x 3, três lâminas de irrigação (100, 300 e 500 mm de água durante o ciclo da cultura e três intervalos de irrigação. Avaliou-se além da severidade do míldio, também a produção e a qualidade dos frutos. Constatou-se que as doses de potássio não influenciaram no progresso do crestamento gomoso e no número, peso médio e qualidade dos frutos. As lâminas de irrigação aplicadas influenciaram no progresso do míldio. Maiores níveis de severidade do míldio foram observados nas plantas mantidas sob irrigação com lâmina de 500 mm de água. As lâminas de água aplicadas também influenciaram significativamente na produção e qualidade dos frutos. Observou-se a presença de maior número de frutos deformados ou tortos nas plantas mantidas sob déficit hídrico, na lâmina de 100 mm. As maiores produtividades comerciais e totais foram obtidas nas plantas irrigadas com a lâmina de 500 mm de água.Among the major diseases of watermelon, gummy stem blight (Didymella bryoniae and downy mildew

  18. Resistance Mechanisms and Molecular Docking Studies of Four Novel QoI Fungicides in Peronophythora litchii.

    Science.gov (United States)

    Zhou, Yuxin; Chen, Lei; Hu, Jian; Duan, Hongxia; Lin, Dong; Liu, Pengfei; Meng, Qingxiao; Li, Bin; Si, Naiguo; Liu, Changling; Liu, Xili

    2015-12-14

    Peronophythora litchii is the causal agent of litchi downy blight. Enestroburin, SYP-1620, SYP-2815 and ZJ0712 are four novel QoI fungicides developed by China. Eight mutants of P. litchii resistant to these QoI fungicides and azoxystrobin (as a known QoI fungicide) were obtained in our preliminary work. In this study, the full length of the cytochrome b gene in P. litchii, which has a full length of 382 amino acids, was cloned from both sensitive isolates and resistant mutants, and single-site mutations G142A, G142S, Y131C, or F128S were found in resistant mutants. Molecular docking was used to predict how the mutations alter the binding of the five QoI fungicides to the Qo-binding pockets. The results have increased our understanding of QoI fungicide-resistance mechanisms and may help in the development of more potent inhibitors against plant diseases in the fields.

  19. The Present Development and Utilization of Vanilla Germplasm Resources%香荚兰属种质研究与利用现状

    Institute of Scientific and Technical Information of China (English)

    梁淑云; 吴刚; 杨逢春; 张翠玲; 文慧婷

    2009-01-01

    香荚兰属植物分布全球热带地区,南北纬27°以内,全世界有近110种.目前在我国发现有4种,即台湾香荚兰(Vanilla somai Hayata)、深圳香荚兰(Vanilla shenzhenica Z.J.Liu & S.C.Chen)、越南香荚兰(Vanilla shenzhenica Gagnep)和大香荚兰(Vanilla siamensis Rolfe ex Downie),分布在广西、贵州、云南、海南、广东以及台湾等地潮湿的热带山沟谷林下.商业栽培的香荚兰主要是墨西哥香荚兰(Vanilla planifolia Ames),以生产芳香的豆荚而著称.笔者结合研究工作,对国内外香荚兰种质资源的分类和资源分布、细胞染色体、遗传多样性和资源保护利用等进行了总结和分析,对香荚兰种质资源研究发展前景进行了探讨.

  20. SOYBEAN AND CASEIN HYDROLYSATES INDUCE GRAPEVINE IMMUNE RESPONSES AND RESISTANCE AGAINST PLASMOPARA VITICOLA

    Directory of Open Access Journals (Sweden)

    Nihed eLachhab

    2014-12-01

    Full Text Available Plasmopara viticola, the causal agent of grapevine downy mildew, is one of the most devastating grape pathogen in Europe and North America. Although phytochemicals are used to control pathogen infections, the appearance of resistant strains and the concern for possible adverse effects on environment and human health are increasing the search for alternative strategies. In the present investigation, we successfully tested two protein hydrolysates from soybean (soy and casein (cas to trigger grapevine resistance against P. viticola. On Vitis vinifera cv. Marselan plants, the application of soy and cas reduced the infected leaf surface by 76 and 63%, as compared to the control, respectively. Since both hydrolysates might trigger the plant immunity, we investigated their ability to elicit grapevine defence responses. On grapevine cell suspensions, a different free cytosolic calcium signature was recorded for each hydrolysate, whereas a similar transient phosphorylation of two MAP kinases of 45 and 49 kDa was observed. These signalling events were followed by transcriptome reprogramming, including the up-regulation of defence genes encoding pathogenesis-related (PR proteins and the stilbene synthase enzyme responsible for the biosynthesis of resveratrol, the main grapevine phytoalexin. Liquid chromatography analyses confirmed the production of resveratrol and its dimer metabolites, δ- and ε-viniferins. Overall, soy effects were more pronounced as compared to the cas one. Both hydrolysates proved to act as elicitors to enhance grapevine immunity against pathogen attack.

  1. Rational Design of Highly Potent and Slow-Binding Cytochrome bc1 Inhibitor as Fungicide by Computational Substitution Optimization

    Science.gov (United States)

    Hao, Ge-Fei; Yang, Sheng-Gang; Huang, Wei; Wang, Le; Shen, Yan-Qing; Tu, Wen-Long; Li, Hui; Huang, Li-Shar; Wu, Jia-Wei; Berry, Edward A.; Yang, Guang-Fu

    2015-01-01

    Hit to lead (H2L) optimization is a key step for drug and agrochemical discovery. A critical challenge for H2L optimization is the low efficiency due to the lack of predictive method with high accuracy. We described a new computational method called Computational Substitution Optimization (CSO) that has allowed us to rapidly identify compounds with cytochrome bc1 complex inhibitory activity in the nanomolar and subnanomolar range. The comprehensively optimized candidate has proved to be a slow binding inhibitor of bc1 complex, ~73-fold more potent (Ki = 4.1 nM) than the best commercial fungicide azoxystrobin (AZ; Ki = 297.6 nM) and shows excellent in vivo fungicidal activity against downy mildew and powdery mildew disease. The excellent correlation between experimental and calculated binding free-energy shifts together with further crystallographic analysis confirmed the prediction accuracy of CSO method. To the best of our knowledge, CSO is a new computational approach to substitution-scanning mutagenesis of ligand and could be used as a general strategy of H2L optimisation in drug and agrochemical design.

  2. Influence of Nitrogen Availability on Growth of Two Transgenic Birch Species Carrying the Pine GS1a Gene

    Science.gov (United States)

    Lebedev, Vadim G.; Kovalenko, Nina P.; Shestibratov, Konstantin A.

    2017-01-01

    An alternative way to increase plant productivity through the use of nitrogen fertilizers is to improve the efficiency of nitrogen utilization via genetic engineering. The effects of overexpression of pine glutamine synthetase (GS) gene and nitrogen availability on growth and leaf pigment levels of two Betula species were studied. Untransformed and transgenic plants of downy birch (B. pubescens) and silver birch (B. pendula) were grown under open-air conditions at three nitrogen regimes (0, 1, or 10 mM) for one growing season. The transfer of the GS1a gene led to a significant increase in the height of only two transgenic lines of nine B. pubescens, but three of five B. pendula transgenic lines were higher than the controls. In general, nitrogen supply reduced the positive effect of the GS gene on the growth of transgenic birch plants. No differences in leaf pigment levels between control and transgenic plants were found. Nitrogen fertilization increased leaf chlorophyll content in untransformed plants but its effect on most of the transgenic lines was insignificant. The results suggest that birch plants carrying the GS gene use nitrogen more efficiently, especially when growing in nitrogen deficient soil. Transgenic lines were less responsive to nitrogen supply in comparison to wild-type plants. PMID:28067821

  3. PRE-PLANTING TREATMENTS WITH PHOSPHITE-BASED PRODUCTS AGAINST DIFFERENT FOLIAR AND SOIL-BORNE PATHOGENS OF VEGETABLE CROPS.

    Science.gov (United States)

    Gilardi, G; Demarchi, S; Ramon, I; Gullino, M L; Garibaldi, A

    2015-01-01

    Fifteen experimental trials were carried out under greenhouse conditions to evaluate the efficacy of preventative treatments based on phosphite salts on the following pathosystems: tomato/Phytophthora nicotianae, zucchini/P. capsici, lettuce/Fusarium oxysporum f.sp. Iactucae, rocket/Fusarium oxysporum f. sp. raphani, wild rocket/Plectosphaerella cucumerina and basii/Peronospora belbahrii. The possible use of phosphite salts in nursery cultivation systems is considered in comparison with chemical fungicides. Phosphites-based products reduced 66-88% and 56-72% the severity of Phytophthora crown root rot of tomato and zucchini, respectively. Four application with the phosphites-based products provided a disease reduction of Fusarium wilt of lettuce from of 33 to 83% and of 45 to 68% on cultivated rocket. These products provide the most constant results when applied in three treatments against Plectosphaerella cucumerina with a disease reduction ranging between 34%-82%. Phosphite-based products showed results statistically similar to mefenoxam when tested against downy mildew of basil. Their contribution to disease management can be very interesting, because they can complement other control measures.

  4. 春大白菜新品种‘晋春2号’%A New Spring Chinese Cabbage Hybrid ‘Jinchun 2'

    Institute of Scientific and Technical Information of China (English)

    李改珍; 巫东堂; 赵军良; 王秀英; 赵俊

    2013-01-01

    'Jinchun 2' is a new hybrid of early-mid maturity spring Chinese cabbage, with a growth period of 70 - 75 days. Compactly closed, its head is medium-sized and shell-shaped. It has a good taste and a good marketability. The average plant weight is 2.0 - 2.5 kg, the average yield is 72 000 - 78 000 kg · hm-2. Due to its resistance to viral diseases, downy mildew and soft rot disease, it can be planted in central and southern Shanxi province and the same ecological types of area.%‘晋春2号’为早中熟春大白菜一代杂交种.生育期70~75 d,叶球合抱,中桩,炮弹形,商品性好,品质佳,单株质量2.0~2.5kg,净菜产量72 000~78 000 kg·hm-2,抗病毒病、霜霉病和软腐病,在山西省中南部及全国同生态类型地区均可种植.

  5. Identification of Hyaloperonospora arabidopsidis transcript sequences expressed during infection reveals isolate-specific effectors.

    Directory of Open Access Journals (Sweden)

    Adriana Cabral

    Full Text Available Biotrophic plant pathogens secrete effector proteins that are important for infection of the host. The aim of this study was to identify effectors of the downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa that are expressed during infection of its natural host Arabidopsis thaliana. Infection-related transcripts were identified from Expressed Sequence Tags (ESTs derived from leaves of the susceptible Arabidopsis Ws eds1-1 mutant inoculated with the highly virulent Hpa isolate Waco9. Assembly of 6364 ESTs yielded 3729 unigenes, of which 2164 were Hpa-derived. From the translated Hpa unigenes, 198 predicted secreted proteins were identified. Of these, 75 were found to be Hpa-specific and six isolate Waco9-specific. Among 42 putative effectors identified there were three Elicitin-like proteins, 16 Cysteine-rich proteins and 18 host-translocated RXLR effectors. Sequencing of alleles in different Hpa isolates revealed that five RXLR genes show signatures of diversifying selection. Thus, EST analysis of Hpa-infected Arabidopsis is proving to be a powerful method for identifying pathogen effector candidates expressed during infection. Delivery of the Waco9-specific protein RXLR29 in planta revealed that this effector can suppress PAMP-triggered immunity and enhance disease susceptibility. We propose that differences in host colonization can be conditioned by isolate-specific effectors.

  6. Activation tagging of ATHB13 in Arabidopsis thaliana confers broad-spectrum disease resistance.

    Science.gov (United States)

    Gao, Dongli; Appiano, Michela; Huibers, Robin P; Chen, Xi; Loonen, Annelies E H M; Visser, Richard G F; Wolters, Anne-Marie A; Bai, Yuling

    2014-12-01

    Powdery mildew species Oidium neolycopersici (On) can cause serious yield losses in tomato production worldwide. Besides on tomato, On is able to grow and reproduce on Arabidopsis. In this study we screened a collection of activation-tagged Arabidopsis mutants and identified one mutant, 3221, which displayed resistance to On, and in addition showed a reduced stature and serrated leaves. Additional disease tests demonstrated that the 3221 mutant exhibited resistance to downy mildew (Hyaloperonospora arabidopsidis) and green peach aphid (Myzus persicae), but retained susceptibility to bacterial pathogen Pseudomonas syringae pv tomato DC3000. The resistance trait and morphological alteration were mutually linked in 3221. Identification of the activation tag insertion site and microarray analysis revealed that ATHB13, a homeodomain-leucine zipper (HD-Zip) transcription factor, was constitutively overexpressed in 3221. Silencing of ATHB13 in 3221 resulted in the loss of both the morphological alteration and resistance, whereas overexpression of the cloned ATHB13 in Col-0 and Col-eds1-2 backgrounds resulted in morphological alteration and resistance. Microarray analysis further revealed that overexpression of ATHB13 influenced the expression of a large number of genes. Previously, it was reported that ATHB13-overexpressing lines conferred tolerance to abiotic stress. Together with our results, it appears that ATHB13 is involved in the crosstalk between abiotic and biotic stress resistance pathways.

  7. Epigenetic Regulation of Intronic Transgenes in Arabidopsis

    Science.gov (United States)

    Osabe, Kenji; Harukawa, Yoshiko; Miura, Saori; Saze, Hidetoshi

    2017-01-01

    Defense mechanisms of plant genomes can epigenetically inactivate repetitive sequences and exogenous transgenes. Loss of mutant phenotypes in intronic T-DNA insertion lines by interaction with another T-DNA locus, termed T-DNA suppression, has been observed in Arabidopsis thaliana, although the molecular basis of establishment and maintenance of T-DNA suppression is poorly understood. Here we show that maintenance of T-DNA suppression requires heterochromatinisation of T-DNA sequences and the nuclear proteins, INCREASED IN BONSAI METHYLATION 2 (IBM2) and ENHANCED DOWNY MILDEW 2 (EDM2), which prevent ectopic 3′ end processing of mRNA in atypically long introns containing T-DNA sequences. Initiation of T-DNA suppression is mediated by the canonical RdDM pathway after hybridisation of two T-DNA strains, accompanied by DNA hypermethylation of T-DNA sequences in the F1 generation. Our results reveal the presence of a genome surveillance mechanism through genome hybridisation that masks repetitive DNAs intruding into transcription units. PMID:28338020

  8. Motion-defined form processing in extremely premature children.

    Science.gov (United States)

    Jakobson, L S; Frisk, V; Downie, A L S

    2006-01-01

    Children born extremely prematurely are at risk for a variety of problems with motion analysis, including problems with motion-defined (MD) form recognition [Downie, A. L. S., Jakobson, L. S., Frisk, V., & Ushycky, I. (2003). Periventricular brain injury, visual motion processing, and reading and spelling abilities in children who were extremely-low-birthweight. Journal of the International Neuropsychological Society, 9, 440-449]. The aims of the present study were (1) to examine the impact of retinopathy of prematurity (ROP) and mild periventricular brain injury (PVBI) on MD form processing in this population; (2) to assess relationships between MD form recognition in these children and their performance in several other areas of visual competence. To this end, a battery of visual and visuomotor tests was administered to 43, 5- and 6-year old, extremely premature children, all of whom had escaped severe PVBI. A group of full-term controls was also studied. Relative to controls, premature children displayed clear deficits in MD form recognition and these deficits were related to the presence of ROP and/or mild PVBI, rather than to a history of prematurity per se. Regression analyses revealed significant associations in premature children between MD form processing deficits and problems with visual search, stereopsis, visuoconstructive and graphomotor skills, motor development, and Performance IQ. The results suggest that assessment of sensitivity to MD forms may be useful in the early identification of preterm children at greatest risk for visual problems associated with dorsal stream dysfunction.

  9. Arboreal ants use the "Velcro(R) principle" to capture very large prey.

    Science.gov (United States)

    Dejean, Alain; Leroy, Céline; Corbara, Bruno; Roux, Olivier; Céréghino, Régis; Orivel, Jérôme; Boulay, Raphaël

    2010-06-25

    Plant-ants live in a mutualistic association with host plants known as "myrmecophytes" that provide them with a nesting place and sometimes with extra-floral nectar (EFN) and/or food bodies (FBs); the ants can also attend sap-sucking Hemiptera for their honeydew. In return, plant-ants, like most other arboreal ants, protect their host plants from defoliators. To satisfy their nitrogen requirements, however, some have optimized their ability to capture prey in the restricted environment represented by the crowns of trees by using elaborate hunting techniques. In this study, we investigated the predatory behavior of the ant Azteca andreae which is associated with the myrmecophyte Cecropia obtusa. We noted that up to 8350 ant workers per tree hide side-by-side beneath the leaf margins of their host plant with their mandibles open, waiting for insects to alight. The latter are immediately seized by their extremities, and then spread-eagled; nestmates are recruited to help stretch, carve up and transport prey. This group ambush hunting technique is particularly effective when the underside of the leaves is downy, as is the case for C. obtusa. In this case, the hook-shaped claws of the A. andreae workers and the velvet-like structure of the underside of the leaves combine to act like natural Velcro that is reinforced by the group ambush strategy of the workers, allowing them to capture prey of up to 13,350 times the mean weight of a single worker.

  10. Identification of Tsuga Germplasm by Morphological Characters and RAPD Markers

    Institute of Scientific and Technical Information of China (English)

    ROH Mark S; DE BENEDETTI Laura; JOUNG Young Hee; LEE Nam Sook

    2007-01-01

    Germplasm collection is important to preserve and maximize genetic diversity for germplasm conservation. Tsuga dumosa (D. Don) Eichler in Engler & Prantl. and T. chinensis var. forrestii (Downie) Silba germplasm was collected from three localities in China: Mt. Yulong, Wenfeng Temple and Mt. Dishiergu, Yunnan Province. Accessions were identified based on morphological characters and RAPD markers. The shapes of the apices and margins of needles were examined, and the length and width of needles, cones and seeds from accessions of mature plants were used to compare the morphological differences and to identify the germplasm. Molecular markers generated by randomly amplified polymorphic DNA (RAPD) were also used to characterize the taxa. Although the clustering based on RAPD markers was inconsistent with the morphological characters of the needles, based on the overall morphological characters and on RAPD markers, the accessions from Mt. Yulong and Wenfeng Temple were identified as T. chinensis var. forrestii, and those from Mt. Dishiergu identified as T. dumosa. Taxonomic identification of the accessions was made based on morphology and by RAPD markers concurred. The results indicate that the shapes of the apices and margins of needles particularly from young plants could not be used as a possible key to identify T. dumosa and T. chinensis var. forrestii. Fig 6, Tab 3, Ref 24

  11. Identification of Genetic Variation between Obligate Plant Pathogens Pseudoperonospora cubensis and P. humuli Using RNA Sequencing and Genotyping-By-Sequencing.

    Directory of Open Access Journals (Sweden)

    Carly F Summers

    Full Text Available RNA sequencing (RNA-seq and genotyping-by-sequencing (GBS were used for single nucleotide polymorphism (SNP identification from two economically important obligate plant pathogens, Pseudoperonospora cubensis and P. humuli. Twenty isolates of P. cubensis and 19 isolates of P. humuli were genotyped using RNA-seq and GBS. Principle components analysis (PCA of each data set showed genetic separation between the two species. Additionally, results supported previous findings that P. cubensis isolates from squash are genetically distinct from cucumber and cantaloupe isolates. A PCA-based procedure was used to identify SNPs correlated with the separation of the two species, with 994 and 4,231 PCA-correlated SNPs found within the RNA-seq and GBS data, respectively. The corresponding unigenes (n = 800 containing these potential species-specific SNPs were then annotated and 135 putative pathogenicity genes, including 3 effectors, were identified. The characterization of genes containing SNPs differentiating these two closely related downy mildew species may contribute to the development of improved detection and diagnosis strategies and improve our understanding of host specificity pathways.

  12. A review on important maize diseases and their management in Nepal

    Directory of Open Access Journals (Sweden)

    Subash Subedi

    2015-12-01

    Full Text Available In Nepal, maize ranks second after rice both in area and production. In recent years, maize area and production has shown a steady increase, but productivity has been low (2.46 t/ha. The major maize producing regions in Nepal are mid hill (72.85%, terai (17.36% and high hill (9.79% respectively. A literature review was carried out to explore major maize diseases and their management in Nepal. The omnipresent incidence of diseases at the pre harvest stage has been an important bottleneck in increasing production. Till now, a total of 78 (75 fungal and 3 bacterial species are pathogenic to maize crop in Nepal. The major and economically important maize diseases reported are Gray leaf spot, Northern leaf blight, Southern leaf Blight, Banded leaf and sheath blight, Ear rot, Stalk rot, Head smut, Common rust, Downy mildew and Brown spot. Information on bacterial and virus diseases, nematodes and yield loss assessment is also given. Description of the major maize diseases, their causal organisms, distribution, time and intensity of disease incidence, symptoms, survival, spreads, environmental factors for disease development, yield losses and various disease management strategies corresponded to important maize diseases of Nepal are gathered and compiled thoroughly from the available publications. Concerted efforts of NARC commodity programs, divisions, ARS and RARS involving research on maize pathology and their important outcomes are mentioned. The use of disease management methods focused on host resistance has also been highlighted.

  13. Can synthetic pesticides be replaced with biologically-based alternatives?--an industry perspective.

    Science.gov (United States)

    Froyd, J D

    1997-09-01

    Agricultural chemical companies have invested in the discovery and development of biological pesticides to complement synthetic pesticides for the control of insects, diseases, and weeds on agronomic and horticultural crops. For plant disease control, companies envisage biological fungicides entering markets where they have the best chance of performing and which are most receptive to using biological control methods. Fewer regulatory requirements can mean faster registration for a biological than a synthetic pesticide. However, industry's requirements for competitive performance, effective formulations, and economic production can mean significant investments in time and money for a biological pesticide, although total investment may be less than for a synthetic pesticide. One biocontrol project in which industry has invested is baculoviruses for insect control. Insect baculoviruses, genetically modified to kill insects faster than wild-type viruses, are attractive biocontrol agents because their selectivity to insect pests and safety to beneficial insects and mammals enable them to compete with synthetic insecticides. Industry is looking for similar biocontrol opportunities in disease control. Biocontrol agents for seedling disease, root rot, and postharvest disease control have been registered by the EPA and are trying to compete with synthetic fungicides for market share. To date, effective biocontrol agents have not been identified for the control of serious foliar diseases, such as grape downy mildew, potato late blight, wheat powdery mildew, and apple scab. Farmers must rely on synthetic fungicides and agronomic methods to control these diseases for the foreseeable future.

  14. Antimicrobial Activity of Resveratrol Analogues

    Directory of Open Access Journals (Sweden)

    Malik Chalal

    2014-06-01

    Full Text Available Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew. Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold. The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups and antimicrobial activity.

  15. Solar radiation affects grapevine susceptibility to Plasmopara Viticola Radiação solar e susceptibilidade da videira à Plasmopara Viticola

    Directory of Open Access Journals (Sweden)

    Anna Dalla Marta

    2008-12-01

    Full Text Available Solar radiation plays an important role in the development of some fungal diseases due to its direct action on the microorganisms and also its indirect effect on the production of specific plant compounds. This experiment examined the effect of two light environments (100% and 35% of full strength on the polyphenolic content of grapevine leaves and quantified their relation to resistance to downy mildew (Plasmopara viticola. Leaf epidermal polyphenolic contents were non-destructively measured during the growing season 2006 using the Dualex chlorophyll fluorescence-based portable leaf-clip. The experimental design consisted of six parcels of 30 vines and measurements were performed on the 12 central vines. The leaves were inoculated with a sporangia suspension containing 50,000 sporangia of P. viticola per mL and the disease severity was assessed after the appearance of symptoms. Leaves maintained at 100% sun had high polyphenolic content and significantly lower disease severity compared to leaves under shading nets. These results indicate an inverse relationship between produced polyphenolics and downy mildew severity.A radiação solar exerce papel importante no desenvolvimento de algumas doenças fúngicas, devido à sua ação direta sobre os microorganismos e também devido ao seu efeito indireto sobre a produção de compostos específicos nas plantas. Este experimento examinou o efeito de dois ambientes de luz (100% e 35% da intensidade máxima sobre o conteúdo de polifenóis nas folhas da videira e quantificou sua relação com a resistência ao míldio (Plasmopara viticola. As concentrações de polifenóis na epiderme das folhas foram quantificadas de forma não destrutiva, durante a estação de crescimento de 2006, usando o equipamento portátil Dualex, baseado na fluorescência da clorofila. O delineamento experimental consistiu de seis parcelas de 30 videiras e as medidas foram feitas nas 12 plantas centrais. As folhas foram

  16. DIVERSIDAD GENÉTICA DE Peronospora sparsa (PERONOSPORACEAE EN CULTIVOS DE ROSA DE COLOMBIA Genetic Diversity of Peronospora sparsa (Peronosporaceae on Rose Crops From Colombia

    Directory of Open Access Journals (Sweden)

    MARILUZ AYALA-VÁSQUEZ

    Full Text Available El mildeo velloso de la rosa es la enfermedad más limitante de este cultivo en Colombia . Aunque algunos trabajos de investigación se han adelantado recientemente sobre la epidemiología de esta enfermedad, uno de los campos menos estudiados es el nivel de variabilidad de su agente causal. El conocimiento de este aspecto es fundamental para definir las estrategias de manejo, especialmente aquellas relacionadas con la resistencia genética y el control químico. Los objetivos de esta investigación fueron confirmar la identidad taxonómica del agente causal del mildeo velloso de la rosa y profundizar en el conocimiento de su estructura poblacional en Colombia . Para esto se colectaron 34 aislamientos del pseudohongo en cultivos de rosas ubicados en Antioquia y la sabana de Bogotá y se extrajo su ADN, para proceder a la amplificación mediante PCR de la región ITS del ADNr utilizando los primers especieespecíficos PS3 y PS1. Dichos productos se emplearon tanto para su secuenciación directa como para la evaluación de variabilidad genética mediante la técnica PCRRFLP, resultados que se complementaron con la utilización de los marcadores RAPD y RAMS. La presencia de un amplicón de aproximadamente 700 pb que compartió un porcentaje de identidad del 100% con secuencias depositadas en el GenBank, permitió confirmar a los aislamientos como pertenecientes a Peronospora sparsa, mientras que el análisis de RFLP, RAPD y RAMS indicó un muy bajo nivel de variabilidad entre todos los aislamientos, concluyéndose que la población de P. sparsa en Colombia es predominantemente clonal.Downy mildew of roses is the most restrictive disease of this crop in Colombia . Although some studies have been carried out on the epidemiology of this disease, one of the fields less studied is the level of variability of its causal agent. The knowledge of this aspect is fundamental to define management strategies, especially those related with the genetic resistance

  17. Habitat Evaluation Procedures (HEP) Report : Hellsgate Project, 1999-2000 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Matthew

    2000-05-01

    A Habitat Evaluation Procedure (HEP) study was conducted on lands acquired and/or managed (4,568 acres total) by the Hellsgate Big Game Winter Range Wildlife Mitigation Project (Hellsgate project) to mitigate some of the losses associated with the original construction and operation of Grand Coulee Dam and inundation of habitats behind the dams. Three separate properties, totaling 2,224 acres were purchased in 1998. One property composed of two separate parcels, mostly grassland lies southeast of the town of Nespelem in Okanogan County (770 acres) and was formerly called the Hinman property. The former Hinman property lies within an area the Tribes have set aside for the protection and preservation of the sharp-tailed grouse (Agency Butte unit). This special management area minus the Hinman acquisition contains 2,388 acres in a long-term lease with the Tribes. The second property lies just south of the Silver Creek turnoff (Ferry County) and is bisected by the Hellsgate Road (part of the Friedlander unit). This parcel contains 60 acres of riparian and conifer forest cover. The third property (now named the Sand Hills unit) acquired for mitigation (1,394 acres) lies within the Hellsgate Reserve in Ferry County. This new acquisition links two existing mitigation parcels (the old Sand Hills parcels and the Lundstrum Flat parcel, all former Kuehne purchases) together forming one large unit. HEP team members included individuals from the Colville Confederated Tribes Fish and Wildlife Department (CTCR), Washington Department of Fish and Wildlife (WDFW), and Bureau of Land Management (BLM). The HEP team conducted a baseline habitat survey using the following HEP species models: mule deer (Odocoileus hemionus), mink (Mustela vison), downy woodpecker (Picoides pubescens), bobcat (Lynx rufus), yellow warbler (Dendroica petechia), and sharp-tailed grouse (Tympanuchus phasianellus columbianus). HEP analysis and results are discussed within the body of the text. The cover types

  18. Negative impacts of invasive plants on conservation of sensitive desert wildlife

    Science.gov (United States)

    Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.

    2016-01-01

    . rubens, indicating potential greater susceptibility to disease or other health-related problems. This study highlights the negative indirect effects of invasive grasses, such as red brome, in desert ecosystems, and provides definitive evidence of a larger negative consequence to health, survival, and ultimately population recruitment for Mojave Desert tortoises than previously understood.

  19. Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease.

    Science.gov (United States)

    Zhang, Rui; Duhl, Tiffany; Salam, Muhammad T; House, James M; Flagan, Richard C; Avol, Edward L; Gilliland, Frank D; Guenther, Alex; Chung, Serena H; Lamb, Brian K; VanReken, Timothy M

    2013-03-01

    Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the WRF/CMAQ air-quality modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation) threshold conditions and is designed to be flexible with respect to its representation of vegetation species and plant functional types (PFTs). The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 km and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to underestimate walnut and peak oak pollen concentrations, and tends

  20. Tillandsia recurvata L. (Bromeliaceae: aspectos farmacognósticos

    Directory of Open Access Journals (Sweden)

    Alex Lucena de Vasconcelos

    2013-01-01

    Full Text Available A cobertura superior das florestas tropicais, formada pelas copas das árvores, constitui um ambiente de extrema diversidade vegetal. Contribuindo com a grande riqueza dessas florestas encontram-se as espécies botânicas epífitas, cuja importância pode ser observada do ponto de vista ecológico, faunístico, etnobotânico e até mesmo farmacológico. Dentre as espécies adaptadas à vida epifítica podemos citar as bromeliáceas, que compõem uma das famílias mais representativas dessa flora com elevada variabilidade genética. Tillandsia recurvata é uma espécie epífita cosmopolita, nativa, adaptada a habitats áridos, utilizada para o tratamento de diversas doenças, mas pouco se tem publicado a respeito das comprovações científicas de suas propriedades. O presente trabalho revisa os aspectos etnofarmacológicos, atividades biológicas e compostos químicos relacionados à espécie em questão, pertencente à Bromeliaceae. A partir do levantamento de dados realizado, observa-se que esta se trata de uma espécie de conhecido uso popular no tratamento de diferentes distúrbios, com alguns estudos farmacológicos que comprovam suas propriedades terapêuticas. Do ponto de vista químico observa-se a presença de terpenos, flavonoides e derivados cinâmicos em sua constituição, em que alguns compostos isolados ilustram a potencialidade desta espécie como fonte de biomoléculas de interesse. Todos estes aspectos considerados nesta revisão contribuem para o conhecimento a respeito da importância biológica e o potencial terapêutico acerca dos metabólitos desta promissora espécie.

  1. Bosques montanos-relictos en Kañaris (Lambayeque, Perú

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    Santos Llatas-Quiroz

    2013-05-01

    Full Text Available En Kañaris (Lambayeque se encuentran grandes bosques relictos, probablemente los mayores de la vertiente occidental de los Andes peruanos. Actualmente están muy bien conservados, pero al mismo tiempo es la zona botánicamente menos estudiada de todos los bosques relictos de la zona. Estos bosques se ubican en las alturas de Upaypiteq y adyacentes a los flancos de la cordillera occidental de los Andes en la vertiente del Atlántico: Shin Shin, San Lorenzo, Huacapampa, Pandachí, Gramalote, Walte, Mollepampa; entre los 1500 a 3000 m sobre el nivel del mar, en el distrito de Kañaris (2300 m y los bosques de Chiñama y Luto en la vertiente del Pacífico. La presente investigación se emprendió con el objeto de estudiar científicamente, mediante muestreos florísticos, la vida y estructura de los componentes de los bosques de Upaypiteq. Las muestras conducen a un avance de la investigación, determinando que los principales componentes arbóreos corresponden a las Lauráceas: Persea, Ocotea y Nectandra, Cunoniáceas: Weinmannia, Podocarpáceas: Podocarpus, Cecropiáceas: Cecropia, Mirtáceas: Myrcianthes, Moráceas: Ficus, Rubiáceas: Cinchona, Bignoniáceas: Tabebuia, Arecáceas: Ceroxylon y, helechos arborescentes del género Nephelea. Circundantes a la masa boscosa se encuentran varias especies de arbustos, de los géneros Miconia, Munnozia, Baccharis, Senna, Colignonia, Gaiadendron, Oreopanax, etc.; también en la estructura es muy frecuente las epífitas y lianas ascendentes: Bromeliáceas, Orquídeas, Heliconias, Aráceas, musgos. Los helechos herbáceos, hongos, líquenes gelatinosos, hepáticas, Balanoforáceas y Begonias, tapizan por completo el piso boscoso. La composición florística es similar al bosque de Cutervo y los bosques de la Vertiente Oriental de los Andes, que a los demás bosques relictos en la Vertiente Occidental. La presencia de estos bosques se debe preservar, por su importancia en los procesos ecológicos para la

  2. Comparison of lime and fly ash as amendments to acidic coal mine refusej growth responses and trace-element uptake of two grasses

    Energy Technology Data Exchange (ETDEWEB)

    Jasrow, J. D.; Zimmerman, C. A.; Dvorak, A. J.; Hinchman, R. R.

    1979-10-01

    Two commonly used revegetation species, Kentucky 31 tall fescue (Festuca arundinacea Schreb.) and Lincoln smooth brome (Bromus inermis Leyss.) were grown for 60 days in pots containing coarse coal mine refuse (referred to as gob, pH = 3.5) that was amended with lime or alkaline fly ash. Both species were also grown in pots containing a silt-loam surface soil as a control. Morphological growth parameters were measured over time; dry weights and shoot:root ratios were determined at harvest. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in the plant shoots were determined by atomic absorption spectrophotometry. Plant growth of both species was not as good on either lime- or fly ash-amended gob as it was on surface soil. Although plant height and length of the longest lead were not significantly different (p > 0.10) at the end of the experiment for plants grown on the two amended-gob substrates, parameters giving an indication of plant vigor (i.e., number of leaves and stems, width of the longest lead, and biomass) were significantly greater (p < 0.01) for plants grown on lime-amended gob than for those grown on fly ash-amended gob. Significant (p < 0.05) differences in the tissue concentrations of Cd, Co, Fe, Hg, Mn, Pb, V, and Zn were found among the plants grown on the three substrates. Except for Hg and Pb, these elements were higher in plants grown on at least one of the amended-gob substrates than in plants grown on surface soil. Significant substrate differences were not observed for Al, As, Cr, Cu, Ni, and Se. The tissue concentrations of some elements - notably Al, Cu, Fe, Mn, V, and Zn - were high enough in plants from one or more of the substrates to either approach or exceed concentrations that have been reported to be associated with toxic effects in some plant species.

  3. Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

    Science.gov (United States)

    Zhang, R.; Duhl, T.; Salam, M. T.; House, J. M.; Flagan, R. C.; Avol, E. L.; Gilliland, F. D.; Guenther, A.; Chung, S. H.; Lamb, B. K.; VanReken, T. M.

    2014-03-01

    Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD) in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the coupled Weather Research and Forecasting Community Multiscale Air Quality (WRF/CMAQ) modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation) threshold conditions and is designed to be flexible with respect to its representation of vegetation species and plant functional types (PFTs). The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California (USA) for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to

  4. Development of a regional-scale pollen emission and transport modeling framework for investigating the impact of climate change on allergic airway disease

    Directory of Open Access Journals (Sweden)

    R. Zhang

    2013-03-01

    Full Text Available Exposure to bioaerosol allergens such as pollen can cause exacerbations of allergenic airway disease (AAD in sensitive populations, and thus cause serious public health problems. Assessing these health impacts by linking the airborne pollen levels, concentrations of respirable allergenic material, and human allergenic response under current and future climate conditions is a key step toward developing preventive and adaptive actions. To that end, a regional-scale pollen emission and transport modeling framework was developed that treats allergenic pollens as non-reactive tracers within the WRF/CMAQ air-quality modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS model was used to generate a daily pollen pool that can then be emitted into the atmosphere by wind. The STaMPS is driven by species-specific meteorological (temperature and/or precipitation threshold conditions and is designed to be flexible with respect to its representation vegetation species and plant functional types (PFTs. The hourly pollen emission flux was parameterized by considering the pollen pool, friction velocity, and wind threshold values. The dry deposition velocity of each species of pollen was estimated based on pollen grain size and density. An evaluation of the pollen modeling framework was conducted for southern California for the period from March to June 2010. This period coincided with observations by the University of Southern California's Children's Health Study (CHS, which included O3, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nesting domains with horizontal resolutions of 12 km and 4 km were constructed, and six representative allergenic pollen genera were included: birch tree, walnut tree, mulberry tree, olive tree, oak tree, and brome grasses. Under the current parameterization scheme, the modeling framework tends to underestimate walnut and peak oak pollen

  5. Application of radioactivity to subterranean hydraulic engineering (1961); Application de la radioactivite a l'hydraulique souterraine (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Hours, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The search for radioactive tracers for water capable of percolating through permeable grounds without significant absorption has led to the choosing of two isotopes, bromine 82 (half-life 36 hours) and iodine (half-life 8 days), both {gamma} emitters; various combinations of other {gamma} emitters with longer half-lives have been tried but with only partial success. The recent progress in the dosage of tritium should make it possible to widen the field of application of this tracer which is unique in its kind. Being detectable at concentrations of 10{sup -6} to 10{sup -8} curies per cubic meter, the radioactive tracers are suitable for all the usual applications of conventional tracers; furthermore, some original techniques have been devised for measurements of flow, of reservoir capacity, of porosity and of permeability. Techniques based on the absorption and scattering of {gamma}-rays have also been developed for the measurement of the density, the humidity and the porosity of soils, and also for their analysis. Up to the present, radioactivity has been mainly applied to the study of oil-bearing formations. Furthermore, the study of the distribution of natural of thermonuclear tritium has contributed greatly to the study of the hydrological cycle. (author) [French] La recherche de traceurs radioactifs de l'eau susceptibles de circuler a travers les terrains permeables sans retention notable a abouti a la selection de deux isotopes, le brome 82 (periodes 36 heures) et l'iode (periode 8 jours), tous deux emetteurs {gamma}; diverses combinaisons mettant en jeu des emetteurs {gamma} de periode plus longue ont ete essayees, mais avec un succes partiel. Les progres recemment accomplis dans le dosage du tritium doivent permettre une rapide extension de l'emploi de ce traceur unique en son genre. Decelables a des concentrations de 10{sup -6} a 10{sup -8} curies par metre cube, les traceurs radioactifs se pretent a toutes les applications des traceurs

  6. Expressed Sequence Tags from the oomycete Plasmopara halstedii, an obligate parasite of the sunflower

    Directory of Open Access Journals (Sweden)

    Mouzeyar Said

    2007-12-01

    Full Text Available Abstract Background Sunflower downy mildew is a major disease caused by the obligatory biotrophic oomycete Plasmopara halstedii. Little is known about the molecular mechanisms underlying its pathogenicity. In this study we used a genomics approach to gain a first insight into the transcriptome of P. halstedii. Results To identify genes from the obligatory biotrophic oomycete Plasmopara halstedii that are expressed during infection in sunflower (Helianthus annuus L. we employed the suppression subtraction hybridization (SSH method from sunflower seedlings infected by P. halstedii. Using this method and random sequencing of clones, a total of 602 expressed sequence tags (ESTs corresponding to 230 unique sequence sets were identified. To determine the origin of the unisequences, PCR primers were designed to amplify these gene fragments from genomic DNA isolated either from P. halstedii sporangia or from Helianthus annuus. Only 145 nonredundant ESTs which correspond to a total of 373 ESTs (67.7% proved to be derived from P. halstedii genes and that are expressed during infection in sunflower. A set of 87 nonredundant sequences were identified as showing matches to sequences deposited in public databases. Nevertheless, about 7% of the ESTs seem to be unique to P. halstedii without any homolog in any public database. Conclusion A summary of the assignment of nonredundant ESTs to functional categories as well as their relative abundance is listed and discussed. Annotation of the ESTs revealed a number of genes that could function in virulence. We provide a first glimpse into the gene content of P. halstedii. These resources should accelerate research on this important pathogen.

  7. Prediction of biological sensors appearance with ARIMA models as a tool for Integrated Pest Management protocols

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    María Fernández-González

    2015-12-01

    Full Text Available [b]Introduction and objectives.[/b] Powdery mildew caused by [i]Uncinula necator[/i] and Downy mildew produced by [i]Plasmopara viticola[/i] are the most common diseases in the North-West Spain vineyards. Knowledge of airborne spore concentrations could be a useful tool in the Integrated Pest Management protocols in order to reduce the number of pesticide treatments, applied only when there is a real risk of infection. [b]Material and methods. [/b]The study was carried out in a vineyard of the D. O. Ribeiro, in the North-West Spain, during the grapevine active period 2004–2012. A Hirts-type volumetric spore-trap was used for the aerobiological monitoring. [b]Results.[/b] During the study period the annual total [i]U. necator[/i] spores amount ranged from the 578 spores registered in 2007 to the 4,145 spores sampled during 2008. The highest annual total [i]P. viticola[/i] spores quantity was observed in 2010 (1,548 spores and the lowest in 2005 (210 spores. In order to forecast the concentration of fungal spores, ARIMA models were elaborated. [b]Conclusions[/b]. The most accurate models were an ARIMA (3.1.3 for [i]U. necator[/i] and (1.0.3 for [i]P. viticola[/i]. The possibility to forecast the spore presence 72 hours in advance open an important horizon for optimizing the organization of the harvest processes in the vineyard.

  8. Phenolic Compounds and Bioactivity of Healthy and Infected Grapevine Leaf Extracts from Red Varieties Merlot and Vranac (Vitis vinifera L.).

    Science.gov (United States)

    Anđelković, Marko; Radovanović, Blaga; Anđelković, Ana Milenkovic; Radovanović, Vladimir

    2015-09-01

    We investigated the phenolic composition, radical scavenging activity, and antimicrobial activity of grapevine leaf extracts from two red grape varieties, Vranac and Merlot (Vitis vinifera L.). The extracts were prepared from healthy grapevine leaves and those infected by Plasmopara viticola (downy mildew). The phenolic composition of the grapevine leaf extracts was determined using spectrophotometric assays and reverse-phase high performance liquid chromatography (RP-HPLC). The radical scavenging activity of grapevine leaf extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl assay, and their antimicrobial activity was determined by microwell dilution tests. The total phenolic content was higher in healthy grapevine leaf extracts than in infected grapevine leaf extracts. The RP-HPLC analysis detected significant amounts of flavonols, phenolic acids, and flavan-3-ols, and small amounts of stilbenes in the grapevine leaf extracts. Compared with the infected grapevine leaf extracts, the healthy grapevine leaf extracts were richer in flavonols, phenolic acids, and flavan-3-ols, but had lower stilbenes contents. All extracts showed strong free radical scavenging activity, which was strongly correlated with the total phenolic content (R(2) = 0.978). The extracts showed a stronger antimicrobial activity towards Gram-positive bacterial strains than towards Gram-negative bacterial strains and yeast. The phenolic compounds in grapevine leaves were responsible for their strong radical scavenging and antimicrobial activities. Together, these results demonstrate that grapevine leaves have high nutritional value and can be used as a fresh food and to prepare extracts that can be used as additives in food and medicines.

  9. Mandipropamid targets the cellulose synthase-like PiCesA3 to inhibit cell wall biosynthesis in the oomycete plant pathogen, Phytophthora infestans.

    Science.gov (United States)

    Blum, Mathias; Boehler, Martine; Randall, Eva; Young, Vanessa; Csukai, Michael; Kraus, Sabrina; Moulin, Florence; Scalliet, Gabriel; Avrova, Anna O; Whisson, Stephen C; Fonne-Pfister, Raymonde

    2010-03-01

    Oomycete plant pathogens cause a wide variety of economically and environmentally important plant diseases. Mandipropamid (MPD) is a carboxylic acid amide (CAA) effective against downy mildews, such as Plasmopara viticola on grapes and potato late blight caused by Phytophthora infestans. Historically, the identification of the mode of action of oomycete-specific control agents has been problematic. Here, we describe how a combination of biochemical and genetic techniques has been utilized to identify the molecular target of MPD in P. infestans. Phytophthora infestans germinating cysts treated with MPD produced swelling symptoms typical of cell wall synthesis inhibitors, and these effects were reversible after washing with H(2)O. Uptake studies with (14)C-labelled MPD showed that this oomycete control agent acts on the cell wall and does not enter the cell. Furthermore, (14)C glucose incorporation into cellulose was perturbed in the presence of MPD which, taken together, suggests that the inhibition of cellulose synthesis is the primary effect of MPD. Laboratory mutants, insensitive to MPD, were raised by ethyl methane sulphonate (EMS) mutagenesis, and gene sequence analysis of cellulose synthase genes in these mutants revealed two point mutations in the PiCesA3 gene, known to be involved in cellulose synthesis. Both mutations in the PiCesA3 gene result in a change to the same amino acid (glycine-1105) in the protein. The transformation and expression of a mutated PiCesA3 allele was carried out in a sensitive wild-type isolate to demonstrate that the mutations in PiCesA3 were responsible for the MPD insensitivity phenotype.

  10. Transfer of elements relevant to nuclear fuel cycle from soil to boreal plants and animals in experimental meso- and microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Tuovinen, Tiina S., E-mail: tiina.tuovinen@uef.fi [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland); Kasurinen, Anne; Häikiö, Elina [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland); Tervahauta, Arja [Department of Biology, University of Eastern Finland, P.O. Box FI-70211, Kuopio (Finland); Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka [Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2016-01-01

    Uranium (U), cobalt (Co), molybdenum (Mo), nickel (Ni), lead (Pb), thorium (Th) and zinc (Zn) occur naturally in soil but their radioactive isotopes can also be released into the environment during the nuclear fuel cycle. The transfer of these elements was studied in three different trophic levels in experimental mesocosms containing downy birch (Betula pubescens), narrow buckler fern (Dryopteris carthusiana) and Scandinavian small-reed (Calamagrostis purpurea ssp. Phragmitoides) as producers, snails (Arianta arbostorum) as herbivores, and earthworms (Lumbricus terrestris) as decomposers. To determine more precisely whether the element uptake of snails is mainly via their food (birch leaves) or both via soil and food, a separate microcosm experiment was also performed. The element uptake of snails did not generally depend on the presence of soil, indicating that the main uptake route was food, except for U, where soil contact was important for uptake when soil U concentration was high. Transfer of elements from soil to plants was not linear, i.e. it was not correctly described by constant concentration ratios (CR) commonly applied in radioecological modeling. Similar nonlinear transfer was found for the invertebrate animals included in this study: elements other than U were taken up more efficiently when element concentration in soil or food was low. - Highlights: • We studied transfer of elements in boreal food chain using meso- and microcosms. • Elements related to nuclear fuel cycle and mining were examined. • Higher uptake at lower soil concentrations was observed for primary producers. • Snails took up elements mainly from food but for U also soil was an element source. • Non-linear transfer of essential elements was observed for herbivore and decomposer.

  11. Predicting infection risk of hop by Pseudoperonospora humuli.

    Science.gov (United States)

    Gent, David H; Ocamb, Cynthia M

    2009-10-01

    ABSTRACT Downy mildew, caused by Pseudoperonospora humuli, is one of the most destructive diseases of hop. Weather factors associated with infection risk by P. humuli in the maritime region of western Oregon were examined for 24- and 48-h periods and quadratic discriminant function models were developed to classify periods as favorable for disease development on leaves. For the 24-h data sets, the model with superior predictive ability included variables for hours of relative humidity>80%, degree-hours of wetness, and mean night temperature. The same variables were selected for the 48-h data sets, with the addition of a product variable for mean night temperature and hours of relative humidity>80%. Cut-points (pT) on receiver operating characteristic curves that minimized the overall error rate were identified by selecting the cut-point with the highest value of Youden's index. For the 24- and 48-h models these were pT=0.49 and 0.39, respectively. With these thresholds, the sensitivity and specificity of the models in cross validation by jackknife exclusion were 83.3 and 88.8% for the 24-h model and 87.5 and 84.4% for the 48-h model, respectively. Cut-points that minimized the average costs associated with disease control and crop loss due to classification errors were determined using estimates of economic damage during vegetative development and on cones near harvest. Use of the 24- and 48-h models was estimated to reduce average management costs during vegetative development when disease prevalence was decisions informed by the models reduced average costs when disease prevalence was models, respectively. The value of the models in management decisions was greatest when disease prevalence was relatively low during vegetative development, which generally corresponds to the normally drier period from late spring to midsummer in the Pacific Northwest of the United States.

  12. Inhibitory effects of macrotetrolides from Streptomyces spp. on zoosporogenesis and motility of peronosporomycete zoospores are likely linked with enhanced ATPase activity in mitochondria

    Directory of Open Access Journals (Sweden)

    Md Tofazzal Islam

    2016-11-01

    Full Text Available The release of zoospores from sporangia and motility of the released zoospores are critical in the disease cycle of the Peronosporomycetes that cause devastating diseases in plants, fishes, animals and humans. Disruption of any of these asexual life stages eliminates the possibility of pathogenesis. In the course of screening novel bioactive secondary metabolites, we found that extracts of some strains of marine Streptomyces spp. rapidly impaired motility and caused subsequent lysis of zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10 g/ml. We tested a number of secondary metabolites previously isolated from these strains and found that macrotetrolide antibiotics such as nonactin, monactin, dinactin and trinactin, and nactic acids such as (+-nonactic acid, (+-homonactic acid, nonactic acid methyl ester, homonactic acid methyl ester, bonactin and feigrisolide C impaired motility and caused subsequent lysis of P. viticola zoospores in a dose- and time-dependent manners with dinactin being the most active compound (MIC 0.3 g/ml. A cation channel-forming compound, gramicidin, and a carrier of monovalent cations, nigericin also showed similar biological activities. Among all 12 compounds tested, gramicidin most potently arrested the motility of zoospores at concentrations starting from 0.1 g/ml. All macrotetrolide antibiotics also displayed similar motility impairing activities against P. viticola, Phytophthora capsici and Aphanomyces cochlioides zoospores indicating non-specific biological effects of these compounds towards peronosporomyctes. Furthermore, macrotetrolide antibiotics and gramicidin also markedly suppressed the release of zoospores from sporangia of P. viticola in a dose-dependent manner. As macrotetrolide antibiotics and gramicidin are known as enhancers of mitochondrial ATPase activity, inhibition of zoosporogenesis and motility of zoospores by these compounds are likely linked with hydrolysis of ATP

  13. The sulfated laminarin triggers a stress transcriptome before priming the SA- and ROS-dependent defenses during grapevine's induced resistance against Plasmopara viticola.

    Directory of Open Access Journals (Sweden)

    Adrien Gauthier

    Full Text Available Grapevine (Vitis vinifera is susceptible to many pathogens which cause significant losses to viticulture worldwide. Chemical control is available, but agro-ecological concerns have raised interest in alternative methods, especially in triggering plant immunity by elicitor treatments. The β-glucan laminarin (Lam and its sulfated derivative (PS3 have been previously demonstrated to induce resistance in grapevine against downy mildew (Plasmopara viticola. However, if Lam elicits classical grapevine defenses such as oxidative burst, pathogenesis-related (PR-proteins and phytoalexin production, PS3 triggered grapevine resistance via a poorly understood priming phenomenon. The aim of this study was to identify the molecular mechanisms of the PS3-induced resistance. For this purpose we studied i the signaling events and transcriptome reprogramming triggered by PS3 treatment on uninfected grapevine, ii grapevine immune responses primed by PS3 during P. viticola infection. Our results showed that i PS3 was unable to elicit reactive oxygen species (ROS production, cytosolic Ca(2+ concentration variations, mitogen-activated protein kinase (MAPK activation but triggered a long lasting plasma membrane depolarization in grapevine cells, ii PS3 and Lam shared a common stress-responsive transcriptome profile that partly overlapped the salicylate- (SA and jasmonate-(JA-dependent ones. After P. viticola inoculation, PS3 specifically primed the SA- and ROS-dependent defense pathways leading to grapevine induced resistance against this biotroph. Interestingly pharmacological approaches suggested that the plasma membrane depolarization and the downstream ROS production are key events of the PS3-induced resistance.

  14. Dissection of Two Complex Clusters of Resistance Genes in Lettuce (Lactuca sativa).

    Science.gov (United States)

    Christopoulou, Marilena; McHale, Leah K; Kozik, Alex; Reyes-Chin Wo, Sebastian; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-07-01

    Of the over 50 phenotypic resistance genes mapped in lettuce, 25 colocalize to three major resistance clusters (MRC) on chromosomes 1, 2, and 4. Similarly, the majority of candidate resistance genes encoding nucleotide binding-leucine rich repeat (NLR) proteins genetically colocalize with phenotypic resistance loci. MRC1 and MRC4 span over 66 and 63 Mb containing 84 and 21 NLR-encoding genes, respectively, as well as 765 and 627 genes that are not related to NLR genes. Forward and reverse genetic approaches were applied to dissect MRC1 and MRC4. Transgenic lines exhibiting silencing were selected using silencing of β-glucuronidase as a reporter. Silencing of two of five NLR-encoding gene families resulted in abrogation of nine of 14 tested resistance phenotypes mapping to these two regions. At MRC1, members of the coiled coil-NLR-encoding RGC1 gene family were implicated in host and nonhost resistance through requirement for Dm5/8- and Dm45-mediated resistance to downy mildew caused by Bremia lactucae as well as the hypersensitive response to effectors AvrB, AvrRpm1, and AvrRpt2 of the nonpathogen Pseudomonas syringae. At MRC4, RGC12 family members, which encode toll interleukin receptor-NLR proteins, were implicated in Dm4-, Dm7-, Dm11-, and Dm44-mediated resistance to B. lactucae. Lesions were identified in the sequence of a candidate gene within dm7 loss-of-resistance mutant lines, confirming that RGC12G confers Dm7.

  15. Silencing of the major family of NBS-LRR-encoding genes in lettuce results in the loss of multiple resistance specificities.

    Science.gov (United States)

    Wroblewski, Tadeusz; Piskurewicz, Urszula; Tomczak, Anna; Ochoa, Oswaldo; Michelmore, Richard W

    2007-09-01

    The RGC2 gene cluster in lettuce (Lactuca sativa) is one of the largest known families of genes encoding nucleotide binding site-leucine-rich repeat (NBS-LRR) proteins. One of its members, RGC2B, encodes Dm3 which determines resistance to downy mildew caused by the oomycete Bremia lactucae carrying the cognate avirulence gene, Avr3. We developed an efficient strategy for analysis of this large family of low expressed genes using post-transcriptional gene silencing (PTGS). We transformed lettuce cv. Diana (carrying Dm3) using chimeric gene constructs designed to simultaneously silence RGC2B and the GUS reporter gene via the production of interfering hairpin RNA (ihpRNA). Transient assays of GUS expression in leaves accurately predicted silencing of both genes and were subsequently used to assay silencing in transgenic T(1) plants and their offspring. Levels of mRNA were reduced not only for RGC2B but also for all seven diverse RGC2 family members tested. We then used the same strategy to show that the resistance specificity encoded by the genetically defined Dm18 locus in lettuce cv. Mariska is the result of two resistance specificities, only one of which was silenced by ihpRNA derived from RGC2B. Analysis of progeny from crosses between transgenic, silenced tester stocks and lettuce accessions carrying other resistance genes previously mapped to the RGC2 locus indicated that two additional resistance specificities to B. lactucae, Dm14 and Dm16, as well as resistance to lettuce root aphid (Pemphigus bursarius L.), Ra, are encoded by RGC2 family members.

  16. Three combined quantitative trait loci from nonhost Lactuca saligna are sufficient to provide complete resistance of lettuce against Bremia lactucae.

    Science.gov (United States)

    Zhang, Ningwen W; Pelgrom, Koen; Niks, Rients E; Visser, Richard G F; Jeuken, Marieke J W

    2009-09-01

    The nonhost resistance of wild lettuce (Lactuca saligna) to downy mildew (Bremia lactucae) is based on at least 15 quantitative trait loci (QTL), each effective at one or more plant developmental stages. We used QTL pyramiding (stacking) to determine how many of these QTL from L. saligna are sufficient to impart complete resistance towards B. lactucae to cultivated lettuce, L. sativa. The alleles of four of the most promising QTL, rbq4, rbq5, rbq6+11, and rbq7 are effective at both the young and adult plant stages. Lines with these four QTL in all possible combinations were generated by crossing the respective backcross inbred lines (BIL). Using the 11 resulting lines (combiBIL), we determined that combinations of three QTL, rbq4, rbq5, and rbq6+11, led to increased levels of resistance; however, one QTL, rbq7, did not add to the resistance level when combined with the other QTL. One line, tripleBIL268, which contains the three QTL rbq4, rbq5, and rbq6+11, was completely resistant to B. lactucae at the young plant stage. This suggests that these three QTL are sufficient to confer the complete resistance of the nonhost L. saligna and any additional QTL in L. saligna are redundant. Histological analysis of B. lactucae infection in L. saligna, the BIL, and the combiBIL 48 h after inoculation revealed different microscopical phenotypes of resistance. The QTL differed with respect to the stage of the infection process with which they interfered.

  17. sunTILL: a TILLING resource for gene function analysis in sunflower

    Directory of Open Access Journals (Sweden)

    Sabetta Wilma

    2011-06-01

    Full Text Available Abstract Background Cultivated sunflower (Helianthus annus L. is a globally important oilseed crop, subjected to intensive genetic and genomic studies. Although classical mutagenesis has successfully been applied to Helianthus genus in the past, we have developed the first sunflower TILLING resource. Results To balance the maximum mutation density with an acceptable plant survival rate, a 'kill curve' analysis was first conducted with different ethylmethanesulfonate (EMS dosages and different exposure times. According to the germination rate, a treatment with 0.7% EMS for 6 h was chosen. An M2 progeny of 3,651 fertile plants was obtained. Totally, 4.79% of the whole population showed clear aberrant phenotypes. A microsatellite analysis on a representative sample of the original seed stock and mutant lines confirmed the uniformity of the genetic background of plant material. The TILLING procedure was successfully applied to sunflower genome, initially by a CelI-nuclease mismatch cleavage assay coupled with a DNA-pooling level test. To investigate the efficiency of the mutagenic treatment, a pilot screening was carried out on 1,152 M2 lines focusing on four genes, three involved in the fatty acid biosynthetic pathway and one for downy mildew resistance. A total of 9 mutant lines were identified and confirmed by sequencing; thereby, the estimated overall mutation frequency for the pilot assay resulted to be 1/475 kb. Conclusion A first TILLING population for a high throughput identification of EMS-induced point mutations in sunflower genome has been successfully obtained. This represents a powerful tool to a better understanding of gene function in sunflower.

  18. The major resistance gene cluster in lettuce is highly duplicated and spans several megabases.

    Science.gov (United States)

    Meyers, B C; Chin, D B; Shen, K A; Sivaramakrishnan, S; Lavelle, D O; Zhang, Z; Michelmore, R W

    1998-11-01

    At least 10 Dm genes conferring resistance to the oomycete downy mildew fungus Bremia lactucae map to the major resistance cluster in lettuce. We investigated the structure of this cluster in the lettuce cultivar Diana, which contains Dm3. A deletion breakpoint map of the chromosomal region flanking Dm3 was saturated with a variety of molecular markers. Several of these markers are components of a family of resistance gene candidates (RGC2) that encode a nucleotide binding site and a leucine-rich repeat region. These motifs are characteristic of plant disease resistance genes. Bacterial artificial chromosome clones were identified by using duplicated restriction fragment length polymorphism markers from the region, including the nucleotide binding site-encoding region of RGC2. Twenty-two distinct members of the RGC2 family were characterized from the bacterial artificial chromosomes; at least two additional family members exist. The RGC2 family is highly divergent; the nucleotide identity was as low as 53% between the most distantly related copies. These RGC2 genes span at least 3.5 Mb. Eighteen members were mapped on the deletion breakpoint map. A comparison between the phylogenetic and physical relationships of these sequences demonstrated that closely related copies are physically separated from one another and indicated that complex rearrangements have shaped this region. Analysis of low-copy genomic sequences detected no genes, including RGC2, in the Dm3 region, other than sequences related to retrotransposons and transposable elements. The related but divergent family of RGC2 genes may act as a resource for the generation of new resistance phenotypes through infrequent recombination or unequal crossing over.

  19. Transposon tagging of disease resistance genes. Progress report, May 1, 1988--1992

    Energy Technology Data Exchange (ETDEWEB)

    Michelmore, R.

    1994-06-01

    Our goal is to clone genes in lettuce determining resistance to downy mildew. One approach involves the mobilization of transposons into resistance genes to mutate and tag the target gene. Because transposons have yet to be isolated and characterized from lettuce, the majority of our experiments have involved Ac from corn as this is increasingly the best characterized transposon. Over the past several years, various labs have contributed to a detailed understanding of the biology of Ac in corn and heterologous plant species. We have collaborated closely with several of these labs, exchanged materials and incorporated their advances into our analysis of transposition in lettuce. The original proposal described the development of a transposon mutagenesis system for lettuce and its subsequent use to tag disease resistance genes. The development phase involved characterization and manipulation of Ac transposition, identification of suitable whole plant selectable markers for the construction of chimeric non-autonomous elements, and investigation of the stability of resistance genes. Investigation of Ac transposition in lettuce has received the majority of our attention. Initially, we made a simple construct with wildtype Ac and introduced it into lettuce. No transposition was observed; although other labs demonstrated that the same construct was functional in tomato. We then focused on assaying for Ac transposition with constructs of increasing sophistication that had been demonstrated by others to be functional in other species. The latest constructs for transposon mutagenesis clearly demonstrated transposition in lettuce. This allowed us to generate seed stocks that we will start to screen for insertional inactivation of resistance genes this year.

  20. A new disjunct eddy-covariance system for BVOC flux measurements – validation on CO2 and H2O fluxes

    Directory of Open Access Journals (Sweden)

    N. Striebig

    2012-06-01

    Full Text Available The disjunct eddy covariance (DEC method is an interesting alternative to the conventional eddy covariance (EC method, because it allows the estimation of turbulent fluxes of species for which fast sensors are not available. A new disjunct sampling system (called MEDEE was developed and validated. This system was built with chemically inert materials. Air samples are grabbed quickly and alternately in two cylindrical reservoirs, whose internal pressures are regulated by a moving piston. It was designed to be operated either on ground or aboard an airplane (the French ATR-42 research aircraft. It is also compatible with most analysers since it transfers the air samples at a regulated pressure. For validating the system, DEC and EC measurements of CO2 and latent heat fluxes were performed concurrently during a field campaign. EC fluxes were first compared to simulated DEC (SDEC fluxes and then to actual DEC fluxes. The EC fluxes were in agreement with both the simulated and actual DEC fluxes. The EC fluxes compare well to SDEC fluxes (R2 = 0.92 and 0.68 for latent heat and CO2 fluxes, respectively and to actual DEC fluxes (R2 = 0.91 and 0.67 for latent heat and CO2 fluxes, respectively, in spite of low fluxes experienced during the campaign. This good agreement between the two techniques demonstrates that MEDEE is suitable for DEC measurements and highlights the DEC method as a reliable alternative to EC for slower sensors. A first field campaign focused on biogenic volatile organic compound (BVOC emissions was done to measure isoprene fluxes above a downy oak (Quercus Pubescens forest in the southeast of France. The measured emission rates were in good agreement with the values reported in earlier studies. Further analysis will be conducted from ground-based and airborne campaigns in the forthcoming years.