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Sample records for phytophthora brassicae zoospores

  1. A novel method for efficient and abundant production of Phytophthora brassicae zoospores on Brussels sprout leaf discs

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    Govers Francine

    2009-08-01

    Full Text Available Abstract Background Phytophthora species are notorious oomycete pathogens that cause diseases on a wide range of plants. Our understanding how these pathogens are able to infect their host plants will benefit greatly from information obtained from model systems representative for plant-Phytophthora interactions. One attractive model system is the interaction between Arabidopsis and Phytophthora brassicae. Under laboratory conditions, Arabidopsis can be easily infected with mycelial plugs as inoculum. In the disease cycle, however, sporangia or zoospores are the infectious propagules. Since the current P. brassicae zoospore isolation methods are generally regarded as inefficient, we aimed at developing an alternative method for obtaining high concentrations of P. brassicae zoospores. Results P. brassicae isolates were tested for pathogenicity on Brussels sprout plants (Brassica oleracea var. gemmifera. Microscopic examination of leaves, stems and roots infected with a GFP-tagged transformant of P. brassicae clearly demonstrated the susceptibility of the various tissues. Leaf discs were cut from infected Brussels sprout leaves, transferred to microwell plates and submerged in small amounts of water. In the leaf discs the hyphae proliferated and abundant formation of zoosporangia was observed. Upon maturation the zoosporangia released zoospores in high amounts and zoospore production continued during a period of at least four weeks. The zoospores were shown to be infectious on Brussels sprouts and Arabidopsis. Conclusion The in vitro leaf disc method established from P. brassicae infected Brussels sprout leaves facilitates convenient and high-throughput production of infectious zoospores and is thus suitable to drive small and large scale inoculation experiments. The system has the advantage that zoospores are produced continuously over a period of at least one month.

  2. Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.

    Science.gov (United States)

    Kong, Ping; McDowell, John M; Hong, Chuanxue

    2017-01-01

    Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF) and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA) and jasmonic acid (JA): eds16 (enhanced disease susceptibility16), pad4 (phytoalexin deficient4), and npr1 (nonexpressor of pathogenesis-related genes1). Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.

  3. Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Ping Kong

    Full Text Available Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA and jasmonic acid (JA: eds16 (enhanced disease susceptibility16, pad4 (phytoalexin deficient4, and npr1 (nonexpressor of pathogenesis-related genes1. Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.

  4. Defective zoospore encystment and suppressed cyst germination of Phytophthora palmivora caused by transient leaching treatments

    NARCIS (Netherlands)

    Dijksterhuis, J; Deacon, J W

    2003-01-01

    The behaviour of encysting zoospores of Phytophthora palmivora during leaching conditions was studied. Zoospores encysted and germinated successfully on polycarbonate membranes after mechanical agitation. Transient (10 min) leaching treatments with nutrient-free buffer underneath the membranes

  5. Zoosporic Tolerance to pH Stress and Its Implications for Phytophthora Species in Aquatic Ecosystems▿

    OpenAIRE

    Kong, Ping; Moorman, Gary W.; Lea-Cox, John D.; Ross, David S.; Richardson, Patricia A.; Hong, Chuanxue

    2009-01-01

    Phytophthora species, a group of destructive plant pathogens, are commonly referred to as water molds, but little is known about their aquatic ecology. Here we show the effect of pH on zoospore survival of seven Phytophthora species commonly isolated from irrigation reservoirs and natural waterways and dissect zoospore survival strategy. Zoospores were incubated in a basal salt liquid medium at pH 3 to 11 for up to 7 days and then plated on a selective medium to determine their survival. The ...

  6. An efficient method for zoospore production, infection and real-time quantification of Phytophthora cajani causing Phytophthora blight disease in pigeonpea under elevated atmospheric CO₂.

    Science.gov (United States)

    Sharma, Mamta; Ghosh, Raju; Tarafdar, Avijit; Telangre, Rameshwar

    2015-03-25

    Phytophthora blight caused by Phytophthora cajani is an emerging disease of pigeonpea (Cajanus cajan L.) affecting the crop irrespective of cropping system, cultivar grown and soil types. Current detection and identification methods for Phytophthora species rely primarily on cultural and morphological characteristics, the assessment of which is time-consuming and not always suitable. Sensitive and reliable methods for isolation, identification, zoospore production and estimating infection severity are therefore desirable in case of Phytophthora blight of pigeonpea. In this study, protocols for isolation and identification of Phytophthora blight of pigeonpea were standardized. Also the method for zoospore production and in planta infection of P. cajani was developed. Quantification of fungal colonization by P. cajani using real-time PCR was further standardized. Phytophthora species infecting pigeonpea was identified based on mycological characters such as growth pattern, mycelium structure and sporangial morphology of the isolates and confirmed through molecular characterization (sequence deposited in GenBank). For Phytophthora disease development, zoospore suspension of 1 × 10(5) zoospores per ml was found optimum. Phytophthora specific real-time PCR assay was developed using specific primers based on internal transcribed spacer (ITS) 1 and 2. Use of real-time PCR allowed the quantitative estimation of fungal biomass in plant tissues. Detection sensitivities were within the range of 0.001 pg fungal DNA. A study to see the effect of elevated CO₂ on Phytophthora blight incidence was also conducted which indicated no significant difference in disease incidence, but incubation period delayed under elevated CO₂ as compared to ambient level. The zoospore infection method for Phytophthora blight of pigeonpea will facilitate the small and large scale inoculation experiments and thus devise a platform for rapid and reliable screening against Phytophthora blight

  7. A Myb transcription factor of Phytophthora sojae, regulated by MAP kinase PsSAK1, is required for zoospore development.

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    Meng Zhang

    Full Text Available PsSAK1, a mitogen-activated protein (MAP kinase from Phytophthora sojae, plays an important role in host infection and zoospore viability. However, the downstream mechanism of PsSAK1 remains unclear. In this study, the 3'-tag digital gene expression (DGE profiling method was applied to sequence the global transcriptional sequence of PsSAK1-silenced mutants during the cysts stage and 1.5 h after inoculation onto susceptible soybean leaf tissues. Compared with the gene expression levels of the recipient P. sojae strain, several candidates of Myb family were differentially expressed (up or down in response to the loss of PsSAK1, including of a R2R3-type Myb transcription factor, PsMYB1. qRT-PCR indicated that the transcriptional level of PsMYB1 decreased due to PsSAK1 silencing. The transcriptional level of PsMYB1 increased during sporulating hyphae, in germinated cysts, and early infection. Silencing of PsMYB1 results in three phenotypes: a no cleavage of the cytoplasm into uninucleate zoospores or release of normal zoospores, b direct germination of sporangia, and c afunction in zoospore-mediated plant infection. Our data indicate that the PsMYB1 transcription factor functions downstream of MAP kinase PsSAK1 and is required for zoospore development of P. sojae.

  8. Use of the vital stain FUN-1 indicates viability of Phytophthora capsici propagules and can be used to predict maximum zoospore production.

    Science.gov (United States)

    Lewis Ivey, Melanie L; Miller, Sally A

    2014-01-01

    The fluorescent vital dye FUN®-1 (2-chloro-4-[2,3-dihydro-3-methyl-{benzo-1,3-thiazol-2-yl}-methylidene]-1-phenylquinolinium iodide) was evaluated as a tool to assess Phytophthora capsici sporangia and zoospore metabolic activity and viability. Under aerobic conditions, mycelia, sporangia and zoospores cultured on agar medium and stained with FUN-1 exhibited red fluorescent cylindrical intravacuolar structures (CIVS) that were clearly visible at 100× magnification. Encysted zoospores did not exhibit CIVS after exposure to FUN-1 dye. Over 7 d there was a significant reduction in the percent of sporangia containing CIVS, which corresponded with a significant increase in zoospore formation and release. The decline in the percentage of metabolically active sporangia and increase in the number of zoospores fit both a linear and log regression model. The FUN-1 dye was suitable for distinguishing between live and dead sporangia and effective in monitoring the change in metabolic activity of sporangia over time. It will be useful in determining parameters, including P. capsici culture age, that maximize production of zoospores in vitro.

  9. Effect of arabinogalactan proteins from the root caps of pea and Brassica napus on Aphanomyces euteiches zoospore chemotaxis and germination.

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    Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

    2012-08-01

    Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions.

  10. Effect of Arabinogalactan Proteins from the Root Caps of Pea and Brassica napus on Aphanomyces euteiches Zoospore Chemotaxis and Germination12[C][W

    Science.gov (United States)

    Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

    2012-01-01

    Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions. PMID:22645070

  11. Effect of partially purified components of zoospores and mycelia of phytophthora infestans on uptake of 3H-leucine by potato tuber disks

    International Nuclear Information System (INIS)

    Nishimura, Norio; Tomiyama, Kohei; Doke, Noriyuki

    1980-01-01

    The zoosporial component of Phytophthora infestans, which was previously reported to cause reduction of 3 H-leucine uptake by potato tuber disks, was partially purified. Precipitate (A-fraction) was obtained by homogenizing zoospores with acetate buffer at pH 4.5 and centrifuging at 20,000 x g, and the A-fraction was suspended in borate buffer at pH 8.8, boiled for 1 hr and then centrifuged at 20,000 x g, giving the precipitate (B-fraction) and supernatant (C-fraction). Ten ml of 10 mM tris-HCl buffer containing 1 mM CaCl 2 at pH 7.4 was used to suspend A and B-fraction. The buffer was used as a control. A, B and C fractions obtained from 5 - 6 x 10 6 zoosprores reducted uptake of 3 H-leucine by the tuber disks of potato cv. Rishiri, but the inhibition rates caused by these fractions differed markedly. However, very high correlation was found between inhibition rates of 3 H-leucine uptake and sugar contents of these fractions. There was no difference in the inhibition rates between the zoosporial components of incompatible and compatible races, when the activities were expressed in terms of the sugar contents. The mycelial components of P. infestans extracted by the modified method of Lisker and Kuc which was used to extract phytoalexin elicitor from that of P. infestans, also had the same effect as the zoosporial components (A, B, and C-fraction) on 3 H-leucine uptake by the disks. C-fraction containing 15 μg of sugar per ml sufficed to inhibit 3 H-leucine uptake at the maximum rate, and the maximum rate of inhibition was attained within 2 hr after the zoosporial component (C-fraction containing 30 μg sugar/ml) was administered to the disks. (author)

  12. Tobacco Rotated with Rapeseed for Soil-Borne Phytophthora Pathogen Biocontrol: Mediated by Rapeseed Root Exudates

    Directory of Open Access Journals (Sweden)

    Yuting Fang

    2016-06-01

    Full Text Available Black shank, caused by Phytophthora parasitica var. nicotianae, is a widespread and destructive disease of tobacco. Crop rotation is essential in controlling black shank. Here, we confirmed that rotating black shank-infested fields with rapeseed (Brassica napus suppressed the incidence this disease. Further study demonstrated that rapeseed roots have a strong ability to attract zoospores and subsequently stop the swimming of zoospores into cystospores. Then, rapeseed roots secrete a series of antimicrobial compounds, including 2-butenoic acid, benzothiazole, 2-(methylthiobenzothiazole, 1-(4-ethylphenyl-ethanone, and 4-methoxyindole, to inhibit the cystospore germination and mycelial growth of P. parasitica var. nicotianae. Thus, rapeseed rotated with tobacco suppresses tobacco black shank disease through the chemical weapons secreted by rapeseed roots.

  13. Rhamnolipids as platform molecules for production of potential anti-zoospore agrochemicals.

    Science.gov (United States)

    Miao, Shida; Dashtbozorg, Soroosh Soltani; Callow, Nicholas V; Ju, Lu-Kwang

    2015-04-08

    Rhamnolipid biosurfactants have potential applications in the control of zoosporic plant pathogens. However, rhamnolipids have not been closely investigated for the anti-zoospore mechanism or for developing new anti-zoospore chemicals. In this study, RhL-1 and RhL-3 groups of rhamnolipids were used to generate the corresponding RhL-2 and RhL-4 groups and the free diacids. Conversion of RhL-3 to RhL-1 was also accomplished in vitro with cellobiase as the catalyst. The anti-zoospore effects of RhL-1-RhL-4 and the diacids were investigated with zoospores of Phytophthora sojae. For RhL-1-RhL-4, approximately 20, 30, 40, and 40 mg/L, respectively, were found to be the lowest concentrations required to stop movement of all zoospores, which indicates that the anti-zoospore effect remains strong even after RhL-1 and RhL-3 are hydrolyzed into RhL-2 and RhL-4. The free diacids required a significantly higher critical concentration of about 125 mg/L. Rhamnose can be obtained as a co-product.

  14. Phytophthora cinnamomi.

    Science.gov (United States)

    Hardham, Adrienne R; Blackman, Leila M

    2018-02-01

    Phytophthora cinnamomi is one of the most devastating plant pathogens in the world. It infects close to 5000 species of plants, including many of importance in agriculture, forestry and horticulture. The inadvertent introduction of P. cinnamomi into natural ecosystems, including a number of recognized Global Biodiversity Hotspots, has had disastrous consequences for the environment and the biodiversity of flora and fauna. The genus Phytophthora belongs to the Class Oomycetes, a group of fungus-like organisms that initiate plant disease through the production of motile zoospores. Disease control is difficult in agricultural and forestry situations and even more challenging in natural ecosystems as a result of the scale of the problem and the limited range of effective chemical inhibitors. The development of sustainable control measures for the future management of P. cinnamomi requires a comprehensive understanding of the cellular and molecular basis of pathogen development and pathogenicity. The application of next-generation sequencing technologies to generate genomic and transcriptomic data promises to underpin a new era in P. cinnamomi research and discovery. The aim of this review is to integrate bioinformatic analyses of P. cinnamomi sequence data with current knowledge of the cellular and molecular basis of P. cinnamomi growth, development and plant infection. The goal is to provide a framework for future research by highlighting potential pathogenicity genes, shedding light on their possible functions and identifying suitable targets for future control measures. Phytophthora cinnamomi Rands; Kingdom Chromista; Phylum Oomycota or Pseudofungi; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; genus Phytophthora. Infects about 5000 species of plants, including 4000 Australian native species. Host plants important for agriculture and forestry include avocado, chestnut, macadamia, oak, peach and pineapple. A root pathogen which causes rotting of fine

  15. Validation of the bait test with Rhododendron leaves for Phytophthora diagnosis

    Science.gov (United States)

    Corina Junker; Sabine Werres

    2017-01-01

    Bait tests are very helpful for diagnosis of Phytophthora in for example soil, substrate, water, sediment, and rootball samples (Werres and others 2014). By attracting the motile zoospores of the Phytophthora species with the baits these pathogens can be separated from other organisms. Bait tests are simple and cost...

  16. Stable transformation of the oomycete, Phytophthora infestans, using microprojectile bombardment

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Judelson, Howard S.

    2003-01-01

    Germinated asexual sporangia, zoospores, and mycelia of Phytophthora infestans were transformed to G418-resistance by microprojectile bombardment. After optimization, an average of 14 transformants/shot were obtained, using 10(6) germinated sporangia and gold particles coated with 1 microg...

  17. Slow sand filters effectively reduce Phytophthora after a pathogen switch from Fusarium and a simulated pump failure.

    Science.gov (United States)

    Lee, Eric; Oki, Lorence R

    2013-09-15

    Slow sand filtration has been shown to effectively reduce Phytophthora zoospores in irrigation water. This experiment tested the reduction of Phytophthora colony forming units (CFUs) by slow sand filtration systems after switching the pathogen contaminating plant leachate from Fusarium to Phytophthora and the resilience of the system to a short period without water, as might be caused by a pump failure. The slow sand filtration system greatly reduced Phytophthora CFUs and transmission after switching the pathogens. In addition, Phytophthora reduction by the slow sand filter was equally effective before and after the simulated pump failure. Reduction of Fusarium was not seen by the SSFs, before or after the simulated pump failure. The results suggest that slow sand filters are effective at reducing larger organisms, such as Phytophthora zoospores, even after a pump failure or a change in pathogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Nature of vegetative cycle in Phytophthora parasitica Dastur and palmivora (BUTLER) BUTLER

    International Nuclear Information System (INIS)

    Le Grand-Pernot, Francoise; Pellegrin, F.

    1976-01-01

    Up to now, neither cytological nor genetical studies have clearly demonstrated the 'ploidy' degree of somatic nuclei in different species of Phytophthora. Two complementary studies, using biological effect of γ rays upon zoospores, and microspectrophotometric techniques measuring relative amount of DNA by nucleus in zoospores or in hyphae, allowed to demonstrate diploid nature of the vegetative phase in P. palmivora (BUTLER) BUTLER and P. parasitica DASTUR cycles [fr

  19. Elemental variations in the germinating fungus Phytophthora palmivora

    International Nuclear Information System (INIS)

    Mazzolini, A.P.; Sealock, R.M.; Legge, G.J.F.; Grant, B.R.

    1991-01-01

    We have measured the elemental variations between zoospores and germinating cystospores of the fungus Phytophthora palmivora, using a scanning proton microprobe. Averaged over a number of individual cells, our results indicate that the level of Ca is much lower in germinating cystospores than in zoospores. The levels of S, Cl, and Zn also appear to be lower, and the level of K appears to be higher. The spatial distribution of elements within the germinating cystospore is very similar for P, S, Cl, K, Mn, Fe, and Cu, but significantly different for Ca and Zn. (orig.)

  20. Elemental variations in the germinating fungus Phytophthora palmivora

    Science.gov (United States)

    Mazzolini, A. P.; Grant, B. R.; Sealock, R. M.; Legge, G. J. F.

    1991-03-01

    We have measured the elemental variations between zoospores and germinating cystospores of the fungus Phytophthora palmivora, using a scanning proton microprobe. Averaged over a number of individual cells, our results indicate that the level of Ca is much lower in germinating cystospores than in zoospores. The levels of S, Cl, and Zn also appear to be lower, and the level of K appears to be higher. The spatial distribution of elements within the germinating cystospore is very similar for P, S, Cl, K, Mn, Fe, and Cu, but significantly different for Ca and Zn.

  1. Phytophthora viruses.

    Science.gov (United States)

    Cai, Guohong; Hillman, Bradley I

    2013-01-01

    Phytophthora sp. is a genus in the oomycetes, which are similar to filamentous fungi in morphology and habitat, but phylogenetically more closely related to brown algae and diatoms and fall in the kingdom Stramenopila. In the past few years, several viruses have been characterized in Phytophthora species, including four viruses from Phytophthora infestans, the late blight pathogen, and an endornavirus from an unnamed Phytophthora species from Douglas fir. Studies on Phytophthora viruses have revealed several interesting systems. Phytophthora infestans RNA virus 1 (PiRV-1) and PiRV-2 are likely the first members of two new virus families; studies on PiRV-3 support the establishment of a new virus genus that is not affiliated with established virus families; PiRV-4 is a member of Narnaviridae, most likely in the genus Narnavirus; and Phytophthora endornavirus 1 (PEV1) was the first nonplant endornavirus at the time of reporting. Viral capsids have not been found in any of the above-mentioned viruses. PiRV-1 demonstrated a unique genome organization that requires further examination, and PiRV-2 may have played a role in late blight resurgence in 1980s-1990s. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Gene expression profiling during asexual development of the late blight pathogen Phytophthora infestans reveals a highly dynamic transcriptome

    NARCIS (Netherlands)

    Judelson, H.S.; Ah-Fong, A.M.V.; Aux, G.; Avrova, A.O.; Bruce, C.; Cakir, C.; Cunha, da L.; Grenville-Briggs, L.; Latijnhouwers, M.; Ligterink, W.; Meijer, H.J.G.; Roberts, S.; Thurber, C.S.; Whisson, S.C.; Birch, P.R.J.; Govers, F.; Kamoun, S.; West, van P.; Windass, J.

    2008-01-01

    Much of the pathogenic success of Phytophthora infestans, the potato and tomato late blight agent, relies on its ability to generate from mycelia large amounts of sporangia, which release zoospores that encyst and form infection structures. To better understand these stages, Affymetrix GeneChips

  3. Susceptibility of common alder (Alnus glutinosa) seeds and seedlings to Phytophthora alni and other Phytophthora species

    Energy Technology Data Exchange (ETDEWEB)

    Haque, M. M.; Diez, J. J.

    2012-11-01

    Phytophthora alni is a highly destructive host specific pathogen to alders (Alnus spp.) spreading all over Europe. Recently this pathogen has been reported to cause diseases in common alder (Alnus glutinosa) in Spain. Seeds and seedlings of A. glutinosa were tested in vitro for their susceptibility to alder Phytophthora and other Phytophthora species. Isolates of P. alni ssp. alni, P. cinnamomi, P. citrophthora, P. nicotianae and P. palmivora were used in the experiments. Seeds and seedlings were inoculated with a zoospore suspension and uniform mycelial blocks of agar of the Phytophthora species. Susceptibility was calculated in terms of pathogen virulence on seed germination and seedling mortality 42 and 67 days after inoculation respectively. Seed germination and seedling mortality rates varied differently among the isolates used. Results implied that common alder and its seeds and seedlings are at risk to be infected by P. alni. In addition, other Phytophthora species are able to infect this kind of material showing their relative host non-specificity. This is one important finding concerning alder regeneration in infected areas, and the possibility of disease spread on this plant material. (Author) 42 refs.

  4. Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium.

    Science.gov (United States)

    Ali, Mohammad; Kim, Bosung; Belfield, Kevin D; Norman, David; Brennan, Mary; Ali, Gul Shad

    2015-09-01

    Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml⁻¹ of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml⁻¹) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

  5. Establishment of a simple and efficient Agrobacterium-mediated transformation system for Phytophthora palmivora.

    Science.gov (United States)

    Wu, Dongliang; Navet, Natasha; Liu, Yingchao; Uchida, Janice; Tian, Miaoying

    2016-09-06

    As an agriculturally important oomycete genus, Phytophthora contains a large number of destructive plant pathogens that severely threaten agricultural production and natural ecosystems. Among them is the broad host range pathogen P. palmivora, which infects many economically important plant species. An essential way to dissect their pathogenesis mechanisms is genetic modification of candidate genes, which requires effective transformation systems. Four methods were developed for transformation of Phytophthora spp., including PEG(polyethylene glycol)/CaCl2 mediated protoplast transformation, electroporation of zoospores, microprojectile bombardment and Agrobacterium-mediated transformation (AMT). Among them, AMT has many advantages over the other methods such as easy handling and mainly generating single-copy integration in the genome. An AMT method previously reported for P. infestans and P. palmivora has barely been used in oomycete research due to low success and low reproducibility. In this study, we report a simple and efficient AMT system for P. palmivora. Using this system, we were able to reproducibly generate over 40 transformants using zoospores collected from culture grown in a single 100 mm-diameter petri dish. The generated GFP transformants constitutively expressed GFP readily detectable using a fluorescence microscope. All of the transformants tested using Southern blot analysis contained a single-copy T-DNA insertion. This system is highly effective and reproducible for transformation of P. palmivora and expected to be adaptable for transformation of additional Phytophthora spp. and other oomycetes. Its establishment will greatly accelerate their functional genomic studies.

  6. Chemical control trials against Phytophthora capsici (Leon on pepper cultivations in Morocco

    Directory of Open Access Journals (Sweden)

    Pussemier, L.

    1988-01-01

    Full Text Available Chemical control trials against Phytophthora capsici (Leon on pepper cultivations in Morocco. Pepper protection trials against collar and root rot have been undertaken under laboratory and culture conditions using Aliette (80 % of phosethylaluminium and Ridomil M 58 (10 % of metalaxyl associated to 48 % of maneb. It has been proved that, contrary to Ridomil M 58, Aliette does not protect the hostplant when the Phytophthora capsici (Leon zoospores are used as inoculum. But both fongicides are active when inoculating with a mycelian suspension. Trials undertaken under plastic glasshouses confirmed the laboratory results both with an artificial inoculation and with a natural one on contaminated soil. Only Ridomil M 58 provides satisfactory protection during the first weeks after the treatment. When disease propagation conditions are particularly favorable (permanent presence of an active inoculum source, the protection given by repeated Ridomil M 58 applications gradually disappears after a few weeks.

  7. Multimodal sensorimotor system in unicellular zoospores of a fungus.

    Science.gov (United States)

    Swafford, Andrew J M; Oakley, Todd H

    2018-01-19

    Complex sensory systems often underlie critical behaviors, including avoiding predators and locating prey, mates and shelter. Multisensory systems that control motor behavior even appear in unicellular eukaryotes, such as Chlamydomonas , which are important laboratory models for sensory biology. However, we know of no unicellular opisthokonts that control motor behavior using a multimodal sensory system. Therefore, existing single-celled models for multimodal sensorimotor integration are very distantly related to animals. Here, we describe a multisensory system that controls the motor function of unicellular fungal zoospores. We found that zoospores of Allomyces arbusculus exhibit both phototaxis and chemotaxis. Furthermore, we report that closely related Allomyces species respond to either the chemical or the light stimuli presented in this study, not both, and likely do not share this multisensory system. This diversity of sensory systems within Allomyces provides a rare example of a comparative framework that can be used to examine the evolution of sensory systems following the gain/loss of available sensory modalities. The tractability of Allomyces and related fungi as laboratory organisms will facilitate detailed mechanistic investigations into the genetic underpinnings of novel photosensory systems, and how multisensory systems may have functioned in early opisthokonts before multicellularity allowed for the evolution of specialized cell types. © 2018. Published by The Company of Biologists Ltd.

  8. Interactions of Phytophthora capsici with Resistant and Susceptible Pepper Roots and Stems.

    Science.gov (United States)

    Dunn, Amara R; Smart, Christine D

    2015-10-01

    Using host resistance is an important strategy for managing pepper root and crown rot caused by Phytophthora capsici. An isolate of P. capsici constitutively expressing a gene for green fluorescent protein was used to investigate pathogen interactions with roots, crowns, and stems of Phytophthora-susceptible bell pepper 'Red Knight', Phytophthora-resistant bell pepper 'Paladin', and Phytophthora-resistant landrace Criollos de Morelos 334 (CM-334). In this study, the same number of zoospores attached to and germinated on roots of all cultivars 30 and 120 min postinoculation (pi), respectively. At 3 days pi, significantly more secondary roots had necrotic lesions on Red Knight than on Paladin and CM-334 plants. By 4 days pi, necrotic lesions had formed on the taproot of Red Knight but not Paladin or CM-334 plants. Although hyphae were visible in the crowns and stems of all Red Knight plants observed at 4 days pi, hyphae were observed in crowns of only a few Paladin and in no CM-334 plants, and never in stems of either resistant cultivar at 4 days pi. These results improve our understanding of how P. capsici infects plants and may contribute to the use of resistant pepper cultivars for disease management and the development of new cultivars.

  9. Copper (II) Lead (II) and Zinc (II) reduce growth and zoospore release in four zoosporic true fungi from soils of NSW, Australia

    DEFF Research Database (Denmark)

    Henderson, Linda; Pilgaard, Bo; Gleason, Frank

    2015-01-01

    This study examined the responses of a group of four zoosporic true fungi isolated from soils in NSW Australia, to concentrations of toxic metals in the laboratory that may be found in polluted soils. All isolates showed greatest sensitivity to Cu and least sensitivity to Pb. All isolates showed ...... in 60 ppm Cu. If these metals cause similar effects in the field, Cu, Pb and Zn contamination of NSW soils is likely to reduce biomass of zoosporic true fungi. Loss of the fungi may reduce the rate of mineralisation of soil organic matter.......This study examined the responses of a group of four zoosporic true fungi isolated from soils in NSW Australia, to concentrations of toxic metals in the laboratory that may be found in polluted soils. All isolates showed greatest sensitivity to Cu and least sensitivity to Pb. All isolates showed...

  10. Recruitment potential of a green alga Ulva flexuosa Wolfen dark preserved zoospore and its development

    Digital Repository Service at National Institute of Oceanography (India)

    Imchen, T.

    Green Alga Ulva flexuosa Wulfen Dark Preserved Zoospore and Its Development Temjensangba Imchen* National Institute of Oceanography (Council of Scientific and Industrial Research), Goa, India Abstract The recruitment potential and the ability of Ulva... factors play a role in the process of recruitment. Citation: Imchen T (2012) Recruitment Potential of a Green Alga Ulva flexuosa Wulfen Dark Preserved Zoospore and Its Development. PLoS ONE 7(3): e32651. doi:10.1371/journal.pone.0032651 Editor: Ross...

  11. Fungal infection intensity and zoospore output of Atelopus zeteki, a potential acute chytrid supershedder.

    Directory of Open Access Journals (Sweden)

    Graziella V Direnzo

    Full Text Available Amphibians vary in their response to infection by the amphibian-killing chytrid fungus, Batrachochytrium dendrobatidis (Bd. Highly susceptible species are the first to decline and/or disappear once Bd arrives at a site. These competent hosts likely facilitate Bd proliferation because of ineffective innate and/or acquired immune defenses. We show that Atelopus zeteki, a highly susceptible species that has undergone substantial population declines throughout its range, rapidly and exponentially increases skin Bd infection intensity, achieving intensities that are several orders of magnitude greater than most other species reported. We experimentally infected individuals that were never exposed to Bd (n = 5 or previously exposed to an attenuated Bd strain (JEL427-P39; n = 3. Within seven days post-inoculation, the average Bd infection intensity was 18,213 zoospores (SE: 9,010; range: 0 to 66,928. Both average Bd infection intensity and zoospore output (i.e., the number of zoospores released per minute by an infected individual increased exponentially until time of death (t50 = 7.018, p<0.001, t46 = 3.164, p = 0.001, respectively. Mean Bd infection intensity and zoospore output at death were 4,334,422 zoospores (SE: 1,236,431 and 23.55 zoospores per minute (SE: 22.78, respectively, with as many as 9,584,158 zoospores on a single individual. The daily percent increases in Bd infection intensity and zoospore output were 35.4% (SE: 0.05 and 13.1% (SE: 0.04, respectively. We also found that Bd infection intensity and zoospore output were positively correlated (t43 = 3.926, p<0.001. All animals died between 22 and 33 days post-inoculation (mean: 28.88; SE: 1.58. Prior Bd infection had no effect on survival, Bd infection intensity, or zoospore output. We conclude that A. zeteki, a highly susceptible amphibian species, may be an acute supershedder. Our results can inform epidemiological models to estimate Bd outbreak probability, especially as they relate

  12. Fighting phytophthora in blueberries

    Science.gov (United States)

    Phytophthora cinnamomi Rands is a ubiquitous soilborne pathogen associated with root rot in many woody perennial plant species, including highbush blueberry (Vaccinium sp.). To identify genotypes with resistance to the pathogen, cultivars and advanced selections of highbush blueberry were grown in a...

  13. Antifungal Activity and Biochemical Response of Cuminic Acid against Phytophthora capsici Leonian.

    Science.gov (United States)

    Wang, Yong; Sun, Yang; Zhang, Ying; Zhang, Xing; Feng, Juntao

    2016-06-11

    Phytophthora blight of pepper caused by Phytophthora capsici Leonian is a destructive disease throughout the world. Cuminic acid, extracted from the seed of Cuminum cyminum L., belongs to the benzoic acid chemical class. In this study, the sensitivity and biochemical response of P. capsici to cuminic acid was determined. The mean EC50 (50% effective concentration) values for cuminic acid in inhibiting mycelial growth and zoospore germination of the 54 studied P. capsici isolates were 14.54 ± 5.23 μg/mL and 6.97 ± 2.82 μg/mL, respectively. After treatment with cuminic acid, mycelial morphology, sporangium formation and mycelial respiration were significantly influenced; cell membrane permeability and DNA content increased markedly, but pyruvic acid content, adenosine triphosphate (ATP) content, and ATPase activity decreased compared with the untreated control. In pot experiments, cuminic acid exhibited both protective and curative activity. Importantly, POD and PAL activity of the pepper leaves increased after being treated with cuminic acid. These indicated that cuminic acid not only showed antifungal activity, but also could improve the defense capacity of the plants. All the results suggested that cuminic acid exhibits the potential to be developed as a new phytochemical fungicide, and this information increases our understanding of the mechanism of action of cuminic acid against Phytophthora capsici.

  14. Influence of Phytophthora capsici L. inoculation on disease severity, necrosis length, peroxidase and catalase activity, and phenolic content of resistant and susceptible pepper (Capsicum annuum L.) plants

    OpenAIRE

    KOÇ, Esra; ÜSTÜN, Ayşen Sülün

    2014-01-01

    This study explored the level of infection caused by different inoculum concentrations (102, 103, and 104 zoospores mL-1) of Phytophthora capsici in 3 pepper cultivars at days 2, 4, and 6. The effect that the infection induced on the peroxidase (POX), catalase (CAT), and phenolics of resistant and sensitive seedlings, as well as the defense mechanism against the pathogen, were also investigated. The resistance of PM-702 against the isolate used was high, whereas KM-Hot and DEM-8 displayed sen...

  15. Antifungal activity of the osthol derivative JS-B against Phytophthora capsici.

    Science.gov (United States)

    Wang, Chun-Mei; Guan, Wei; Fang, Shu; Chen, Hao; Li, You-Qin; Cai, Chun; Fan, Yong-Jian; Shi, Zhi-Qi

    2010-08-01

    JS-B (C(12)H(10)O(3)) is a derivative compound of osthol. The antifungal properties of JS-B were tested against 10 economically important plant pathogens. JS-B was effective in inhibiting the mycelial growth of Phytophthora capsici, and its inhibition on different stages of the life cycle of P. capsici was observed. The 50% effective concentration (EC(50)) of JS-B on mycelial dry weight and zoospore germination of P. capsici was 43.74 and 86.03 microg/ml, respectively. The rupture of released zoospores induced by JS-B was reduced by the addition of 100 mM glucose. The ultrastructural study showed that JS-B caused destruction of most of the mitochondrions, the concentration of cell nuclear, and the existing vesicles. When compared with dimethomorph, the activity of JS-B on P. capsici was determined under pot conditions. The result showed that JS-B has a curative effect on pepper blight.

  16. An LRR receptor kinase regulates growth, development and pathogenesis in Phytophthora capsici.

    Science.gov (United States)

    Safdar, Asma; Li, Qi; Shen, Danyu; Chen, Linlin; He, Feng; Wang, Rongbo; Zhang, Meixiang; Mafurah, Joseph Juma; Khan, Sajid Aleem; Dou, Daolong

    2017-05-01

    Leucine-rich repeats (LRRs) domain containing kinase proteins (LRR-RK) perform various functions in eukaryotic organisms. However, their functions in Oomycetes are still largely unknown. Here, we identified an LRR-RK (PcLRR-RK1) gene and characterized its functions in Phytophthora capsici, a model oomycete specie and a major plant destroyer of solanaceous and cucurbitaceous vegetable crops. We showed that PcLRR-RK1-silenced P. capsici transformants exhibited reduced growth and produced highly branched fluffy hyphae. The shape and size of sporangia were also altered along with the reduced production of number of sporangia and zoospores. Moreover, silencing of the gene affected the cyst germination and penetration of germ tube into the host tissues, and led to the reduced virulence of P. capsici. Thus, we suggest that PcLRR-RK1 was essentially required for zoospores development, and successful infection of the P. capsici. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  17. Copper (II) lead (II), and zinc (II) reduce growth and zoospore release in four zoosporic true fungi from soils of NSW, Australia.

    Science.gov (United States)

    Henderson, Linda; Pilgaard, Bo; Gleason, Frank H; Lilje, Osu

    2015-07-01

    This study examined the responses of a group of four zoosporic true fungi isolated from soils in NSW Australia, to concentrations of toxic metals in the laboratory that may be found in polluted soils. All isolates showed greatest sensitivity to Cu and least sensitivity to Pb. All isolates showed significant reduction in growth at 60 ppm (0.94 mmol m(-3)) for Cu, while three declined significantly at 60 ppm (0.92 mmol m(-3)) Zn. The growth of two isolates declined significantly at 100 ppm (0.48 mmol m(-3)) Pb and one at 200 ppm (0.96 mmol m(-3)) Pb. The rate of production of zoospores for all isolates was reduced when sporangia were grown in solid PYG media with 60 ppm Cu. Three isolates significantly declined in production at 60 ppm Zn and three at 100 ppm Pb. All isolates recovered growth after incubation in solid media with 60 ppm Zn or 100 ppm Pb. Two isolates did not recover growth after incubation in 60 ppm Cu. If these metals cause similar effects in the field, Cu, Pb, and Zn contamination of NSW soils is likely to reduce biomass of zoosporic true fungi. Loss of the fungi may reduce the rate of mineralisation of soil organic matter. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  18. A novel, multiplexed, probe-based quantitative PCR assay for the soybean root- and stem-rot pathogen, Phytophthora sojae, utilizes its transposable element.

    Science.gov (United States)

    Haudenshield, James S; Song, Jeong Y; Hartman, Glen L

    2017-01-01

    Phytophthora root rot of soybean [Glycine max (L.) Merr.] is caused by the oomycete Phytophthora sojae (Kaufm. & Gerd.). P. sojae has a narrow host range, consisting primarily of soybean, and it is a serious pathogen worldwide. It exists in root and stem tissues as mycelium, wherein it can form oospores which subsequently germinate to release motile, infectious zoospores. Molecular assays detecting DNA of P. sojae are useful in disease diagnostics, and for determining the presence of the organism in host tissues, soils, and runoff or ponded water from potentially infested fields. Such assays as published have utilized ITS sequences from the nuclear ribosomal RNA genes in conventional PCR or dye-binding quantitative PCR (Q-PCR) but are not amenable to multiplexing, and some of these assays did not utilize control strategies for type I or type II errors. In this study, we describe primers and a bifunctional probe with specificity to a gypsy-like retroelement in the P. sojae genome to create a fluorogenic 5'-exonuclease linear hydrolysis assay, with a multiplexed internal control reaction detecting an exogenous target to validate negative calls, and with uracil-deglycosylase-mediated protection against carryover contamination. The assay specifically detected 13 different P. sojae isolates, and excluded 17 other Phytophthora species along with 20 non-Phytophthora fungal and oomycete species pathogenic on soybean. A diagnostic limit of detection of 34 fg total P. sojae DNA was observed in serial dilutions, equivalent to 0.3 genome, and a practical detection sensitivity of four zoospores per sample was achieved, despite losses during DNA extraction.

  19. Can fungal zoospores be the source of energy for the rumen protozoa Eudiplodinium maggii?

    Science.gov (United States)

    Miltko, Renata; Bełżecki, Grzegorz; Kowalik, Barbara; Michałowski, Tadeusz

    2014-10-01

    Results of our earlier studies showed the ability of ciliates Eudiplodinium maggii to digest and metabolize commercial chitin. The natural source of this polysaccharide in the rumen are fungi. The objectives of present research were to determine the effect of fungal zoospores on the survival and population density of E. maggii to quantify the concentration of chitin in the cells of protozoa and to examine the ability of E. maggii, to ferment chitin of fungal zoospores. The cultivation experiment showed that the survival of protozoa was shorter than 4 days when the culture medium was composed of buffer solution and lyophilized fungal spores. An enrichment of this medium with wheat gluten prolonged the survival of ciliates up to 8 days. The supplementation of the last medium with meadow hay enabled the protozoa to survive for 28 days but a positive effect was observed only during the last 8 days of experiment. The chitin content was 0.27 ng and 0.21-0.35 ng per single zoospore and ciliate, respectively. An increase in the concentration of volatile fatty acids (VFA) was found when protozoa were incubated with zoospores. The production rate of VFA was 46.3 pM/protozoan per h whereas the endogenous production did not exceed 31 pM/protozoan per h. The molar proportion of acetic acid was 77.7% and these of butyric and propionic acids-12.2 and 11.0%, respectively. The obtained results make it evident that carbohydrates present in fungal zoospores were utilized by protozoa in energy yielding processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Phytophthora megakarya and Phytophthora palmivora, Closely Related Causal Agents of Cacao Black Pod Rot, Underwent Increases in Genome Sizes and Gene Numbers by Different Mechanisms

    Science.gov (United States)

    Ali, Shahin S.; Shao, Jonathan; Lary, David J.; Kronmiller, Brent A.; Shen, Danyu; Strem, Mary D.; Amoako-Attah, Ishmael; Akrofi, Andrew Yaw; Begoude, B.A. Didier; ten Hoopen, G. Martijn; Coulibaly, Klotioloma; Kebe, Boubacar Ismaël; Melnick, Rachel L.; Guiltinan, Mark J.; Tyler, Brett M.; Meinhardt, Lyndel W.

    2017-01-01

    Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) are closely related species causing cacao black pod rot. Although Ppal is a cosmopolitan pathogen, cacao is the only known host of economic importance for Pmeg. Pmeg is more virulent on cacao than Ppal. We sequenced and compared the Pmeg and Ppal genomes and identified virulence-related putative gene models (PGeneM) that may be responsible for their differences in host specificities and virulence. Pmeg and Ppal have estimated genome sizes of 126.88 and 151.23 Mb and PGeneM numbers of 42,036 and 44,327, respectively. The evolutionary histories of Pmeg and Ppal appear quite different. Postspeciation, Ppal underwent whole-genome duplication whereas Pmeg has undergone selective increases in PGeneM numbers, likely through accelerated transposable element-driven duplications. Many PGeneMs in both species failed to match transcripts and may represent pseudogenes or cryptic genetic reservoirs. Pmeg appears to have amplified specific gene families, some of which are virulence-related. Analysis of mycelium, zoospore, and in planta transcriptome expression profiles using neural network self-organizing map analysis generated 24 multivariate and nonlinear self-organizing map classes. Many members of the RxLR, necrosis-inducing phytophthora protein, and pectinase genes families were specifically induced in planta. Pmeg displays a diverse virulence-related gene complement similar in size to and potentially of greater diversity than Ppal but it remains likely that the specific functions of the genes determine each species’ unique characteristics as pathogens. PMID:28186564

  1. Biocontrol Activity of Myxococcus sp. KYC 1126 against Phytophthora Blight on Hot Pepper

    Directory of Open Access Journals (Sweden)

    Sung Chul Yun

    2011-08-01

    Full Text Available Bacteriolytic myxobacteria have been known to secrete various antifungal metabolites against several soilborne phytopathogens including Phytophthora. Among the three isolates of Myxococcus spp., KYC 1126 and KYC 1136 perfectly inhibited the mycelial growth of Phytophtora capsici in vitro. In order to show the biocontrol activity on Phytophthora blight of hot pepper, we tried to find the best way of application of myxobacterial isolate. Although KYC 1126 fruiting body was easily grown on the colony of Escherichia coli as a nutrient source, it did not control the disease when it was pre-applied in soil. Before the bioassay of a liquid culture filtrate of KYC 1126 was conducted, its antifungal activity was confirmed on the seedlings applying with the mixture of the pathogen`s zoospore suspension and KYC 1126 filtrate. On greenhouse experiments with five and four replications, the control value of KYC 1126 on phyllosphere and rhizosphere was 88% and 36%, respectively. Whereas, the control value of dimetnomorph+propineb on phyllosphere was 100% and that of propamorcarb on rhizosphere was 44%. There was a phytotoxicity of the myxobacterial filtrate when seedlings were washed and soaked for 24 hours. Gummy materials were covered with roots. And stem and petiole were constricted, then a whole seedling was eventually blighted.

  2. Biocontrol of Late Blight (Phytophthora capsici Disease and Growth Promotion of Pepper by Burkholderia cepacia MPC-7

    Directory of Open Access Journals (Sweden)

    Mao Sopheareth

    2013-03-01

    Full Text Available A chitinolytic bacterial strain having strong antifungal activity was isolated and identified as Burkholderia cepacia MPC-7 based on 16S rRNA gene analysis. MPC-7 solubilized insoluble phosphorous in hydroxyapatite agar media. It produced gluconic acid and 2-ketogluconic acid related to the decrease in pH of broth culture. The antagonist produced benzoic acid (BA and phenylacetic acid (PA. The authentic compounds, BA and PA, showed a broad spectrum of antimicrobial activity against yeast, several bacterial and fungal pathogens in vitro. To demonstrate the biocontrol efficiency of MPC-7 on late blight disease caused by Phytophthora capsici, pepper plants in pot trials were treated with modified medium only (M, M plus zoospore inoculation (MP, MPC-7 cultured broth (B and B plus zoospore inoculation (BP. With the sudden increase in root mortality, plants in MP wilted as early as five days after pathogen inoculation. However, plant in BP did not show any symptom of wilting until five days. Root mortality in BP was markedly reduced for as much as 50%. Plants in B had higher dry weight, P concentration in root, and larger leaf area compared to those in M and MP. These results suggested that B. cepacia MPC-7 should be considered as a candidate for the biological fertilizer as well as antimicrobial agent for pepper plants.

  3. Abscisic Acid as a Dominant Signal in Tomato During Salt Stress Predisposition to Phytophthora Root and Crown Rot

    Directory of Open Access Journals (Sweden)

    Matthew F. Pye

    2018-04-01

    Full Text Available Salt stress predisposes plants to Phytophthora root and crown rot in an abscisic acid (ABA-dependent manner. We used the tomato–Phytophthora capsici interaction to examine zoospore chemoattraction and assessed expression of pathogenesis-related (PR genes regulated by salicylic acid (SA and jasmonic acid (JA following a salt-stress episode. Although salt treatment enhances chemoattraction of tomato roots to zoospores, exudates from salt-stressed roots of ABA-deficient mutants, which do not display the predisposition phenotype, have a similar chemoattraction as exudates from salt-stressed, wild-type roots. This suggests that ABA action during predisposing stress enhances disease through effects on plant responses occurring after initial contact and during ingress by the pathogen. The expression of NCED1 (ABA synthesis and TAS14 (ABA response in roots generally corresponded to previously reported changes in root ABA levels during salt stress onset and recovery in a pattern that was not altered by infection by P. capsici. The PR genes, P4 and PI-2, hallmarks in tomato for SA and JA action, respectively, were induced in non-stressed roots during infection and strongly suppressed in infected roots exposed to salt-stress prior to inoculation. However, there was a similar proportional increase in pathogen colonization observed in salt-stressed plants relative to non-stressed plants in both wild-type and a SA-deficient nahG line. Unlike the other tomato cultivars used in this study that showed a strong predisposition phenotype, the processing tomato cv. ‘Castlemart’ and its JA mutants were not predisposed by salt. Salt stress predisposition to crown and root rot caused by P. capsici appears to be strongly conditioned by ABA-driven mechanisms in tomato, with the stress compromising SA-and JA-mediated defense-related gene expression during P. capsici infection.

  4. Tolerance of Brassica nigra to Pieris brassicae herbivory

    NARCIS (Netherlands)

    Blatt, S.E.; Smallegange, R.C.; Hess, L.; Harvey, J.A.; Dicke, M.; Loon, van J.J.A.

    2008-01-01

    Black mustard, Brassica nigra (L.) Koch, is a wild annual species found throughout Europe and fed on by larvae of the large cabbage-white butterfly, Pieris brassicae L. We examined the impact of herbivory from P. brassicae, a gregarious herbivore, on B. nigra grown from wild seed collected locally.

  5. Lipid profiling of the soybean pathogen Phytophthora sojae using Fatty Acid Methyl Esters (FAMEs).

    Science.gov (United States)

    Yousef, Lina Fayez; Wojno, Michal; Dick, Warren A; Dick, Richard P

    2012-05-01

    Phytophthora sojae is a destructive soilborne pathogen of soybean, but currently there is no rapid or commercially available testing for its infestation level in soil. For growers, such information would greatly improve their ability to make management decisions to minimize disease damage to soybean crops. Fatty acid profiling of P. sojae holds potential for determining the prevalence of this pathogen in soil. In this study, the Fatty Acid Methyl Ester (FAME) profile of P. sojae was determined in pure culture, and the profile was subsequently evaluated for its potential use in detecting the pathogen in soil. The predominant fatty acids in the FAME profile of P. sojae are the unsaturated 18C fatty acids (18:1ω9 and 18:2ω6) followed by the saturated and unsaturated 16C fatty acids (16:0 and 16:1ω7). FAME analysis of P. sojae zoospores showed two additional long-chain saturated fatty acids (20:0 and 22:0) that were not detected in the mycelium of this organism. Addition of a known number of zoospores of P. sojae to soil demonstrated that fatty acids such as 18:1ω9, 18:2ω6, 20:1ω9, 20:4ω6, and 22:1ω9 could be detected and quantified against the background levels of fatty acids present in soil. These results show the potential for using selected FAMEs of P. sojae as a marker for detecting this pathogen in soybean fields. Copyright © 2012 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  6. Draft genome sequences of Phytophthora kernoviae and Phytophthora ramorum lineage EU2 from Scotland

    Directory of Open Access Journals (Sweden)

    Christine Sambles

    2015-12-01

    Full Text Available Newly discovered Phytophthora species include invasive pathogens that threaten trees and shrubs. We present draft genome assemblies for three isolates of Phytophthora kernoviae and one isolate of the EU2 lineage of Phytophthora ramorum, collected from outbreak sites in Scotland.

  7. Arabidopsis Lectin Receptor Kinases LecRK-IX.1 and LecRK-IX.2 Are Functional Analogs in Regulating Phytophthora Resistance and Plant Cell Death.

    Science.gov (United States)

    Wang, Yan; Cordewener, Jan H G; America, Antoine H P; Shan, Weixing; Bouwmeester, Klaas; Govers, Francine

    2015-09-01

    L-type lectin receptor kinases (LecRK) are potential immune receptors. Here, we characterized two closely-related Arabidopsis LecRK, LecRK-IX.1 and LecRK-IX.2, of which T-DNA insertion mutants showed compromised resistance to Phytophthora brassicae and Phytophthora capsici, with double mutants showing additive susceptibility. Overexpression of LecRK-IX.1 or LecRK-IX.2 in Arabidopsis and transient expression in Nicotiana benthamiana increased Phytophthora resistance but also induced cell death. Phytophthora resistance required both the lectin domain and kinase activity, but for cell death, the lectin domain was not needed. Silencing of the two closely related mitogen-activated protein kinase genes NbSIPK and NbNTF4 in N. benthamiana completely abolished LecRK-IX.1-induced cell death but not Phytophthora resistance. Liquid chromatography-mass spectrometry analysis of protein complexes coimmunoprecipitated in planta with LecRK-IX.1 or LecRK-IX.2 as bait, resulted in the identification of the N. benthamiana ABC transporter NbPDR1 as a potential interactor of both LecRK. The closest homolog of NbPDR1 in Arabidopsis is ABCG40, and coimmunoprecipitation experiments showed that ABCG40 associates with LecRK-IX.1 and LecRK-IX.2 in planta. Similar to the LecRK mutants, ABCG40 mutants showed compromised Phytophthora resistance. This study shows that LecRK-IX.1 and LecRK-IX.2 are Phytophthora resistance components that function independent of each other and independent of the cell-death phenotype. They both interact with the same ABC transporter, suggesting that they exploit similar signal transduction pathways.

  8. Stability of Cucumber Necrosis Virus at the Quasi-6-Fold Axis Affects Zoospore Transmission.

    Science.gov (United States)

    Sherman, Michael B; Kakani, Kishore; Rochon, D'Ann; Jiang, Wen; Voss, Neil R; Smith, Thomas J

    2017-10-01

    Cucumber necrosis virus (CNV) is a member of the genus Tombusvirus and has a monopartite positive-sense RNA genome. CNV is transmitted in nature via zoospores of the fungus Olpidium bornovanus As with other members of the Tombusvirus genus, the CNV capsid swells when exposed to alkaline pH and EDTA. We previously demonstrated that a P73G mutation blocks the virus from zoospore transmission while not significantly affecting replication in plants (K. Kakani, R. Reade, and D. Rochon, J Mol Biol 338:507-517, 2004, https://doi.org/10.1016/j.jmb.2004.03.008). P73 lies immediately adjacent to a putative zinc binding site (M. Li et al., J Virol 87:12166-12175, 2013, https://doi.org/10.1128/JVI.01965-13) that is formed by three icosahedrally related His residues in the N termini of the C subunit at the quasi-6-fold axes. To better understand how this buried residue might affect vector transmission, we determined the cryo-electron microscopy structure of wild-type CNV in the native and swollen state and of the transmission-defective mutant, P73G, under native conditions. With the wild-type CNV, the swollen structure demonstrated the expected expansion of the capsid. However, the zinc binding region at the quasi-6-fold at the β-annulus axes remained intact. By comparison, the zinc binding region of the P73G mutant, even under native conditions, was markedly disordered, suggesting that the β-annulus had been disrupted and that this could destabilize the capsid. This was confirmed with pH and urea denaturation experiments in conjunction with electron microscopy analysis. We suggest that the P73G mutation affects the zinc binding and/or the β-annulus, making it more fragile under neutral/basic pH conditions. This, in turn, may affect zoospore transmission. IMPORTANCE Cucumber necrosis virus (CNV), a member of the genus Tombusvirus , is transmitted in nature via zoospores of the fungus Olpidium bornovanus While a number of plant viruses are transmitted via insect vectors

  9. Screening Phytophthora rubi for fungicide resistance

    Science.gov (United States)

    Preliminary results from the survey for fungicide resistance in Phytophthora were reported at the 2016 Washington Small Fruit Conference. Phytophthora was isolated from diseased plants in 28 red raspberry fields and tested against mefenoxam, the active ingredient of Ridomil. Most isolates were ident...

  10. Effect of temperature, salinity and biofilm on the zoospores settlement of Enteromorpha flexuosa (Wulfen) J.Agardh

    Digital Repository Service at National Institute of Oceanography (India)

    Imchen, T.

    by permanent adhesion through rapid secretion and curing of an N-linked, self-aggregating glycoprotein that anchors the spore to the substratum surface4. A variety of factors influence settlement of zoospores (biological4; topography of surface5-6; charge...

  11. PsHint1, associated with the G-protein α subunit PsGPA1, is required for the chemotaxis and pathogenicity of Phytophthora sojae.

    Science.gov (United States)

    Zhang, Xin; Zhai, Chunhua; Hua, Chenlei; Qiu, Min; Hao, Yujuan; Nie, Pingping; Ye, Wenwu; Wang, Yuanchao

    2016-02-01

    Zoospore chemotaxis to soybean isoflavones is essential in the early stages of infection by the oomycete pathogen Phytophthora sojae. Previously, we have identified a G-protein α subunit encoded by PsGPA1 which regulates the chemotaxis and pathogenicity of P. sojae. In the present study, we used affinity purification to identify PsGPA1-interacting proteins, including PsHint1, a histidine triad (HIT) domain-containing protein orthologous to human HIT nucleotide-binding protein 1 (HINT1). PsHint1 interacted with both the guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms of PsGPA1. An analysis of the gene-silenced transformants revealed that PsHint1 was involved in the chemotropic response of zoospores to the isoflavone daidzein. During interaction with a susceptible soybean cultivar, PsHint1-silenced transformants displayed significantly reduced infectious hyphal extension and caused a strong cell death in plants. In addition, the transformants displayed defective cyst germination, forming abnormal germ tubes that were highly branched and exhibited apical swelling. These results suggest that PsHint1 not only regulates chemotaxis by interacting with PsGPA1, but also participates in a Gα-independent pathway involved in the pathogenicity of P. sojae. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  12. [Identification of a repetitive sequence element for DNA fingerprinting in Phytophthora sojae].

    Science.gov (United States)

    Yin, Lihua; Wang, Qinhu; Ning, Feng; Zhu, Xiaoying; Zuo, Yuhu; Shan, Weixing

    2010-04-01

    Establishment of DNA fingerprinting in Phytophthora sojae and an analysis of genetic relationship of Heilongjiang and Xinjiang populations. Bioinformatics tools were used to search repetitive sequences in P. sojae and Southern blot analysis was employed for DNA fingerprinting analysis of P. sojae populations from Heilongjiang and Xinjiang using the identified repetitive sequence. A moderately repetitive sequence was identified and designated as PS1227. Southern blot analysis indicated 34 distinct bands ranging in size from 1.5 kb-23 kb, of which 21 were polymorphic among 49 isolates examined. Analysis of single-zoospore progenies showed that the PS1227 fingerprint pattern was mitotically stable. DNA fingerprinting showed that the P. sojae isolates HP4002, SY6 and GJ0105 of Heilongjiang are genetically identical to DW303, 71228 and 71222 of Xinjiang, respectively. A moderately repetitive sequence designated PS1227 which will be useful for epidemiology and population biology studies of P. sojae was obtained, and a PS1227-based DNA fingerprinting analysis provided molecular evidence that P. sojae in Xinjiang was likely introduced from Heilongjiang.

  13. Transcriptome analysis of Phytophthora litchii reveals pathogenicity arsenals and confirms taxonomic status.

    Science.gov (United States)

    Sun, Jinhua; Gao, Zhaoyin; Zhang, Xinchun; Zou, Xiaoxiao; Cao, Lulu; Wang, Jiabao

    2017-01-01

    Litchi downy blight, caused by Peronophythora litchii, is one of the major diseases of litchi and has caused severe economic losses. P. litchii has the unique ability to produce downy mildew like sporangiophores under artificial culture. The pathogen had been placed in a new family Peronophytophthoraceae by some authors. In this study, the whole transcriptome of P. litchii from mycelia, sporangia, and zoospores was sequenced for the first time. A set of 23637 transcripts with an average length of 1284 bp was assembled. Using six open reading frame (ORF) predictors, 19267 representative ORFs were identified and were annotated by searching against several public databases. There were 4666 conserved gene families and various sets of lineage-specific genes among P. litchii and other four closely related oomycetes. In silico analyses revealed 490 pathogen-related proteins including 128 RXLR and 22 CRN effector candidates. Based on the phylogenetic analysis of 164 single copy orthologs from 22 species, it is validated that P. litchii is in the genus Phytophthora. Our work provides valuable data to elucidate the pathogenicity basis and ascertain the taxonomic status of P. litchii.

  14. RNA-Seq Reveals Infection-Related Gene Expression Changes in Phytophthora capsici

    Science.gov (United States)

    Chen, Xiao-Ren; Xing, Yu-Ping; Li, Yan-Peng; Tong, Yun-Hui; Xu, Jing-You

    2013-01-01

    Phytophthora capsici is a soilborne plant pathogen capable of infecting a wide range of plants, including many solanaceous crops. However, genetic resistance and fungicides often fail to manage P. capsici due to limited knowledge on the molecular biology and basis of P. capsici pathogenicity. To begin to rectify this situation, Illumina RNA-Seq was used to perform massively parallel sequencing of three cDNA samples derived from P. capsici mycelia (MY), zoospores (ZO) and germinating cysts with germ tubes (GC). Over 11 million reads were generated for each cDNA library analyzed. After read mapping to the gene models of P. capsici reference genome, 13,901, 14,633 and 14,695 putative genes were identified from the reads of the MY, ZO and GC libraries, respectively. Comparative analysis between two of samples showed major differences between the expressed gene content of MY, ZO and GC stages. A large number of genes associated with specific stages and pathogenicity were identified, including 98 predicted effector genes. The transcriptional levels of 19 effector genes during the developmental and host infection stages of P. capsici were validated by RT-PCR. Ectopic expression in Nicotiana benthamiana showed that P. capsici RXLR and Crinkler effectors can suppress host cell death triggered by diverse elicitors including P. capsici elicitin and NLP effectors. This study provides a first look at the transcriptome and effector arsenal of P. capsici during the important pre-infection stages. PMID:24019970

  15. Rapid and Pervasive Occupation of Fallen Mangrove Leaves by a Marine Zoosporic Fungus †

    OpenAIRE

    Newell, S. Y.; Miller, J. D.; Fell, J. W.

    1987-01-01

    Samples of leaves of red mangrove (Rhizophora mangle) were incubated on an agar medium selective for pythiaceous oomycetes. Leaves on trees above the water did not contain oomycetes. Marine oomycetes, principally Phytophthora vesicula, had colonized leaves within 2 h of leaf submergence, probably finding them by chemotaxis. The frequency of occurrence of P. vesicula in submerged leaves reached 100% within 30 h of submergence. By 43 h most, if not all, parts of leaves were occupied, and surfac...

  16. Deteksi Keberadaan Phytophthora Spp. Di Air

    OpenAIRE

    Sulistyawati, Purnamila

    2014-01-01

    The genus of Phytophthora is a destructive plants pathogen. However the existence of these species in plant tissue was hardly to detect because the fungus may also be present as resistant propagules in soil or spread through waterways. This study aimed to test the FTA card as a direct bait to obtain the DNA of Phytophthora spp and also to investigate the suitability of FTA card as a sampling method. This research used several Phytophthora baits including FTA card followed by DNA extraction a...

  17. Introducing the Phytophthora database: an integrated resource for detecting, monitoring, and managing Phytophthora diseases

    Science.gov (United States)

    Kelly L. Ivors; Frank Martin; Michael Coffey; Izabela Makalowska; David M. Geiser; Seogchan Kang

    2008-01-01

    Its virulence and ability to spread rapidly throughout the world by various means establishes Phytophthora as one of the most important groups of plant pathogens. Discoveries of interspecific hybridization among Phytophthora species in nature, which could yield novel pathogens, further underscore the threat posed by members of this genus. The ability...

  18. Public value at risk from Phytophthora ramorum and Phytophthora kernoviae spread in England and Wales.

    Science.gov (United States)

    Drake, Ben; Jones, Glyn

    2017-04-15

    Heritage gardens, heathland and woodland are increasingly under threat from the non-native tree and plant diseases Phytophthora ramorum and Phytophthora kernoviae. However, there exist only limited literature that estimates the public non-market value that may be lost from a continued spread of Phytophthora ramorum and Phytophthora kernoviae into these habitats. This paper therefore uses a contingent valuation survey to assess the non-extractive public use and non-use values at risk from an uncontrolled spread of these diseases in England and Wales. Results estimate that £1.446bn of public value is at risk in England and Wales per year from an uncontrolled spread of Phytophthora ramorum and Phytophthora kernoviae. The greatest public value at risk, of £578  m/year, is from an uncontrolled spread of these diseases to heritage gardens, while the lowest public value at risk, of £386  m/year, is from disease spread to heathland. The findings of this paper should help policymakers make informed decisions as to the public resources to dedicate towards Phytophthora ramorum and Phytophthora kernoviae control in England and Wales. In this regard, the current control programme to contain these diseases appears cost-effective in light of the public value at risk estimates produced by this paper. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Mitochondrial genomics in the Genus Phytophthora with a focus on Phytophthora ramorum

    Science.gov (United States)

    Frank N. Martin; Paul Richardson

    2008-01-01

    The mitochondrial genomes of Phytophthora infestans, P. ramorum and P. sojae have been sequenced and comparative genomics has provided an opportunity to examine the processes involved with genome evolution in the genus Phytophthora. This approach can also be useful in assessing intraspecific...

  20. Phytophthora rotråte i juletrefelt

    DEFF Research Database (Denmark)

    Talgø, Venche; Thomsen, Iben Margrete

    2015-01-01

    Phytophthora rotråte forårsaket av ulike arter av Phytophthora er et stort problem i juletreproduksjonen iUSA. I Norge er det også rapportert om flere tilfeller av skade på grunn av Phytophthora både i juletrær og klippegrønt, men så langt ikke i Danmark. I begge landene er flere arter av...... Phytophthora funnet på treaktige vekster i grøntanlegg. Vi har også sett en urovekkende spredning av Phytophthora til løvtrær i bynære skoger, vassdrag og naturområder det siste tiåret, spesielt i Norge. Både i Norge og Danmark har vi undersøkt vann i eller like ved juletreplantinger og funnet flere...... Phytophthora-arter, så dette er en skadegjører juletredyrkere må være på vakt overfor...

  1. Inhibition de Phytophthora palmivora, agent de pourriture brune des ...

    African Journals Online (AJOL)

    clonage de la souche par isolement mono zoospores a été effectué selon la technique décrite par Babacauh (1980). 2.2.2. Préparation d'inoculum de P. palmivora et Trichoderma sp. L'inoculum de P. palmivora est constitué d'une suspension de zoospores. Elle est obtenue à partir d'une culture âgée de 5 à 6 jours dans.

  2. Brassica ASTRA: an integrated database for Brassica genomic research.

    Science.gov (United States)

    Love, Christopher G; Robinson, Andrew J; Lim, Geraldine A C; Hopkins, Clare J; Batley, Jacqueline; Barker, Gary; Spangenberg, German C; Edwards, David

    2005-01-01

    Brassica ASTRA is a public database for genomic information on Brassica species. The database incorporates expressed sequences with Swiss-Prot and GenBank comparative sequence annotation as well as secondary Gene Ontology (GO) annotation derived from the comparison with Arabidopsis TAIR GO annotations. Simple sequence repeat molecular markers are identified within resident sequences and mapped onto the closely related Arabidopsis genome sequence. Bacterial artificial chromosome (BAC) end sequences derived from the Multinational Brassica Genome Project are also mapped onto the Arabidopsis genome sequence enabling users to identify candidate Brassica BACs corresponding to syntenic regions of Arabidopsis. This information is maintained in a MySQL database with a web interface providing the primary means of interrogation. The database is accessible at http://hornbill.cspp.latrobe.edu.au.

  3. Identification of cell wall-associated proteins from Phytophthora ramorum

    NARCIS (Netherlands)

    Meijer, H.J.G.; Vondervoort, van de P.J.I.; Yin, Q.Y.; Koster, de C.G.; Klis, F.M.; Govers, F.; Groot, de P.W.J.

    2006-01-01

    The oomycete genus Phytophthora comprises a large group of fungal-like plant pathogens. Two Phytophthora genomes recently have been sequenced; one of them is the genome of Phytophthora ramorum, the causal agent of sudden oak death. During plant infection, extracellular proteins, either soluble

  4. The effects of nitric oxide in settlement and adhesion of zoospores of the green alga Ulva.

    Science.gov (United States)

    Thompson, Stephanie E M; Callow, Maureen E; Callow, James A

    2010-01-01

    Previous studies have shown that elevated nitric oxide (NO) reduces adhesion in diatom, bacterial and animal cells. This article reports experiments designed to investigate whether elevated NO reduces the adhesion of zoospores of the green alga Ulva, an important fouling species. Surface-normalised values of NO were measured using the fluorescent indicator DAF-FM DA and parallel hydrodynamic measurements of adhesion strength were made. Elevated levels of NO caused by the addition of the exogenous NO donor SNAP reduced spore settlement by 20% and resulted in lower adhesion strength. Addition of the NO scavenger cPTIO abolished the effects of SNAP on adhesion. The strength of attachment and NO production by spores in response to four coatings (Silastic T2; Intersleek 700; Intersleek 900 and polyurethane) shows that reduced adhesion is correlated with an increase in NO production. It is proposed that in spores of Ulva, NO is used as an intracellular signalling molecule to detect how conducive a surface is for settlement and adhesion. The effect of NO on the adhesion of a range of organisms suggests that NO-releasing coatings could have the potential to control fouling.

  5. Diagnostics of Tree Diseases Caused by Phytophthora austrocedri Species.

    Science.gov (United States)

    Mulholland, Vincent; Elliot, Matthew; Green, Sarah

    2015-01-01

    We present methods for the detection and quantification of four Phytophthora species which are pathogenic on trees; Phytophthora ramorum, Phytophthora kernoviae, Phytophthora lateralis, and Phytophthora austrocedri. Nucleic acid extraction methods are presented for phloem tissue from trees, soil, and pure cultures on agar plates. Real-time PCR methods are presented and include primer and probe sets for each species, general advice on real-time PCR setup and data analysis. A method for sequence-based identification, useful for pure cultures, is also included.

  6. Phytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d

    Science.gov (United States)

    N. J. Grünwald; S. Werres; E. M. Goss; C. R. Taylor; V. J. Fieland

    2012-01-01

    A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new...

  7. Pathogenicity variation in two west coast forest Phytophthoras, Phytophthora nemorosa and P. pseudosyringae, to bay laurel

    Science.gov (United States)

    R.E. Linzer; M. Garbelotto

    2008-01-01

    Two recently described pathogenic oomycetes, Phytophthora nemorosa and P. pseudosyringae, have overlapping host and geographic ranges in California and Oregon forests with P. ramorum, causal agent of ?sudden oak death? disease. Preliminary genetic evidence indicates P. nemorosa and P....

  8. Phytophthora capsici homologue of the cell cycle regulator SDA1 is required for sporangial morphology, mycelial growth and plant infection.

    Science.gov (United States)

    Zhu, Chunyuan; Yang, Xiaoyan; Lv, Rongfei; Li, Zhuang; Ding, Xiaomeng; Tyler, Brett M; Zhang, Xiuguo

    2016-04-01

    SDA1 encodes a highly conserved protein that is widely distributed in eukaryotic organisms. SDA1 is essential for cell cycle progression and organization of the actin cytoskeleton in yeasts and humans. In this study, we identified a Phytophthora capsici orthologue of yeast SDA1, named PcSDA1. In P. capsici, PcSDA1 is strongly expressed in three asexual developmental states (mycelium, sporangia and germinating cysts), as well as late in infection. Silencing or overexpression of PcSDA1 in P. capsici transformants affected the growth of hyphae and sporangiophores, sporangial development, cyst germination and zoospore release. Phalloidin staining confirmed that PcSDA1 is required for organization of the actin cytoskeleton. Moreover, 4',6-diamidino-2-phenylindole (DAPI) staining and PcSDA1-green fluorescent protein (GFP) fusions revealed that PcSDA1 is involved in the regulation of nuclear distribution in hyphae and sporangia. Both silenced and overexpression transformants showed severely diminished virulence. Thus, our results suggest that PcSDA1 plays a similar role in the regulation of the actin cytoskeleton and nuclear division in this filamentous organism as in non-filamentous yeasts and human cells. © 2015 BSPP and John Wiley & Sons Ltd.

  9. Gene expression profiling during asexual development of the late blight pathogen Phytophthora infestans reveals a highly dynamic transcriptome.

    Science.gov (United States)

    Judelson, Howard S; Ah-Fong, Audrey M V; Aux, George; Avrova, Anna O; Bruce, Catherine; Cakir, Cahid; da Cunha, Luis; Grenville-Briggs, Laura; Latijnhouwers, Maita; Ligterink, Wilco; Meijer, Harold J G; Roberts, Samuel; Thurber, Carrie S; Whisson, Stephen C; Birch, Paul R J; Govers, Francine; Kamoun, Sophien; van West, Pieter; Windass, John

    2008-04-01

    Much of the pathogenic success of Phytophthora infestans, the potato and tomato late blight agent, relies on its ability to generate from mycelia large amounts of sporangia, which release zoospores that encyst and form infection structures. To better understand these stages, Affymetrix GeneChips based on 15,650 unigenes were designed and used to profile the life cycle. Approximately half of P. infestans genes were found to exhibit significant differential expression between developmental transitions, with approximately (1)/(10) being stage-specific and most changes occurring during zoosporogenesis. Quantitative reverse-transcription polymerase chain reaction assays confirmed the robustness of the array results and showed that similar patterns of differential expression were obtained regardless of whether hyphae were from laboratory media or infected tomato. Differentially expressed genes encode potential cellular regulators, especially protein kinases; metabolic enzymes such as those involved in glycolysis, gluconeogenesis, or the biosynthesis of amino acids or lipids; regulators of DNA synthesis; structural proteins, including predicted flagellar proteins; and pathogenicity factors, including cell-wall-degrading enzymes, RXLR effector proteins, and enzymes protecting against plant defense responses. Curiously, some stage-specific transcripts do not appear to encode functional proteins. These findings reveal many new aspects of oomycete biology, as well as potential targets for crop protection chemicals.

  10. Effect of four growth-promoting rhizobacteria on crown blight caused by Phytophthora capsici in sweet pepper (Capsicum annuum

    Directory of Open Access Journals (Sweden)

    Carlos Ramírez

    2015-11-01

    Full Text Available Crown blight, caused by Phytophthora capsici, is the most important disease of pepper (Capsicum annuum in the world and causes great economic losses in Costa Rica. Alternatives to chemical control against this disease are crucial to prevent damage to human health and the environment. The antagonism of Plant-Growth-Promoting Rhizobacteria (PGPR on P. capsici, and its ability to reduce wilt in pepper plants were evaluated. PGPR strains previously isolated from sugarcane and rice were identified, using 16S RNA gene sequence, as Pseudomonas fluorescens PC4, Stenotrophomonas rhizophila PC9, Pseudomonas fragi PC11 and Azospirillum lipoferum PCJ2. The inhibition of P. capcisi growth was evaluated in vitro, in the presence of the PGPR. The effect of the four bacterial strains on pepper plants inoculated with P. capsici (100 zoospores.plant-1 was evaluated in the greenhouse. P. fluorescens PC4, S. rhizophila PC9 and A. lipoferum PCJ2, inhibited in vitro growth of the oomycete by 54%, 30% and 50 % respectively, while S. rhizophila PC9 increased by 14% shoot fresh weight of pepper plants at the greenhouse. Furthermore, PCJ2 and PC9 strains reduced the shoot and root severity of the disease, and PCJ2-inoculated plants showed no symptoms at all, indicating that PC9 and PCJ2 are promising rizobacteria for the control of crown blight in pepper.

  11. De novo assembly of Phlomis purpurea after challenging with Phytophthora cinnamomi.

    Science.gov (United States)

    Baldé, Aladje; Neves, Dina; García-Breijo, Francisco J; Pais, Maria Salomé; Cravador, Alfredo

    2017-09-06

    Phlomis plants are a source of biological active substances with potential applications in the control of phytopathogens. Phlomis purpurea (Lamiaceae) is autochthonous of southern Iberian Peninsula and Morocco and was found to be resistant to Phytophthora cinnamomi. Phlomis purpurea has revealed antagonistic effect in the rhizosphere of Quercus suber and Q. ilex against P. cinnamomi. Phlomis purpurea roots produce bioactive compounds exhibiting antitumor and anti-Phytophthora activities with potential to protect susceptible plants. Although these important capacities of P. purpurea have been demonstrated, there is no transcriptomic or genomic information available in public databases that could bring insights on the genes underlying this anti-oomycete activity. Using Illumina technology we obtained a de novo assembly of P. purpurea transcriptome and differential transcript abundance to identify putative defence related genes in challenged versus non-challenged plants. A total of 1,272,600,000 reads from 18 cDNA libraries were merged and assembled into 215,739 transcript contigs. BLASTX alignment to Nr NCBI database identified 124,386 unique annotated transcripts (57.7%) with significant hits. Functional annotation identified 83,550 out of 124,386 unique transcripts, which were mapped to 141 pathways. 39% of unigenes were assigned GO terms. Their functions cover biological processes, cellular component and molecular functions. Genes associated with response to stimuli, cellular and primary metabolic processes, catalytic and transporter functions were among those identified. Differential transcript abundance analysis using DESeq revealed significant differences among libraries depending on post-challenge times. Comparative cyto-histological studies of P. purpurea roots challenged with P. cinnamomi zoospores and controls revealed specific morphological features (exodermal strips and epi-cuticular layer), that may provide a constitutive efficient barrier against

  12. The kinome of Phytophthora infestans reveals oomycete-specific innovations and links to other taxonomic groups

    Directory of Open Access Journals (Sweden)

    Ah-Fong Audrey MV

    2010-12-01

    Full Text Available Abstract Background Oomycetes are a large group of economically and ecologically important species. Its most notorious member is Phytophthora infestans, the cause of the devastating potato late blight disease. The life cycle of P. infestans involves hyphae which differentiate into spores used for dispersal and host infection. Protein phosphorylation likely plays crucial roles in these stages, and to help understand this we present here a genome-wide analysis of the protein kinases of P. infestans and several relatives. The study also provides new insight into kinase evolution since oomycetes are taxonomically distant from organisms with well-characterized kinomes. Results Bioinformatic searches of the genomes of P. infestans, P. ramorum, and P. sojae reveal they have similar kinomes, which for P. infestans contains 354 eukaryotic protein kinases (ePKs and 18 atypical kinases (aPKs, equaling 2% of total genes. After refining gene models, most were classifiable into families seen in other eukaryotes. Some ePK families are nevertheless unusual, especially the tyrosine kinase-like (TKL group which includes large oomycete-specific subfamilies. Also identified were two tyrosine kinases, which are rare in non-metazoans. Several ePKs bear accessory domains not identified previously on kinases, such as cyclin-dependent kinases with integral cyclin domains. Most ePKs lack accessory domains, implying that many are regulated transcriptionally. This was confirmed by mRNA expression-profiling studies that showed that two-thirds vary significantly between hyphae, sporangia, and zoospores. Comparisons to neighboring taxa (apicomplexans, ciliates, diatoms revealed both clade-specific and conserved features, and multiple connections to plant kinases were observed. The kinome of Hyaloperonospora arabidopsidis, an oomycete with a simpler life cycle than P. infestans, was found to be one-third smaller. Some differences may be attributable to gene clustering, which

  13. Transcription profiling and identification of infection-related genes in Phytophthora cactorum.

    Science.gov (United States)

    Chen, Xiao-Ren; Huang, Shen-Xin; Zhang, Ye; Sheng, Gui-Lin; Zhang, Bo-Yue; Li, Qi-Yuan; Zhu, Feng; Xu, Jing-You

    2018-04-01

    Phytophthora cactorum, an oomycete pathogen, infects more than 200 plant species within several plant families. To gain insight into the repertoire of the infection-related genes of P. cactorum, Illumina RNA-Seq was used to perform a global transcriptome analysis of three life cycle stages of the pathogen, mycelia (MY), zoospores (ZO) and germinating cysts with germ tubes (GC). From over 9.8 million Illumina reads for each library, 18,402, 18,569 and 19,443 distinct genes were identified for MY, ZO and GC libraries, respectively. Furthermore, the transcriptome difference among MY, ZO and GC stages was investigated. Gene ontology (GO) and KEGG pathway enrichment analyses revealed diverse biological functions and processes. Comparative analysis identified a large number of genes that are associated with specific stages and pathogenicity, including 166 effector genes. Of them, most of RXLR and NLP genes showed induction while the majority of CRN genes were down-regulated in GC, the important pre-infection stage, compared to either MY or ZO. And 14 genes encoding small cysteine-rich (SCR) secretory proteins showed differential expression during the developmental stages and in planta. Ectopic expression in the Solanaceae indicated that SCR113 and one elicitin PcINF1 can trigger cell death on Nicotiana benthamiana, tobacco (N. tabacum) and tomato (Solanum lycopersicum) leaves. Neither conserved domain nor homologues of SCR113 in other organisms can be identified. Collectively, our study provides a comprehensive examination of gene expression across three P. cactorum developmental stages and describes pathogenicity-related genes, all of which will help elucidate the pathogenicity mechanism of this destructive pathogen.

  14. Phenolic Compounds in Brassica Vegetables

    Directory of Open Access Journals (Sweden)

    Pablo Velasco

    2010-12-01

    Full Text Available Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

  15. Coast live oak resistance to Phytophthora ramorum

    Science.gov (United States)

    B.A. McPherson; David L. Wood; Sylvia R. Mori; Pierluigi Bonello

    2012-01-01

    The oomycete Phytophthora ramorum is a plant pathogen with an unusually broad host range. Recognized in 2000 as a previously unknown and likely introduced species, this pathogen has become established in central and northern coastal California, southwestern Oregon, and Western Europe. Tree species that may be killed by stem cankers include true...

  16. Geographical distribution of Phytophthora ramorum in Norway

    Science.gov (United States)

    María- Luz Herrero; Brita Toppe; Trond Rafoss

    2008-01-01

    In November 2002, Phytophthora ramorum was detected for the first time in Norway. It was isolated from Rhododendron catawbiense imported earlier the same year. After the first detection, the Norwegian Food Safety Authority has carried out surveys from 2003 to 2006. The surveys were first directed to nurseries and garden centres....

  17. Hot spots of Phytophthora in commercial nurseries

    Science.gov (United States)

    Corina Junker; Patrick Goff; Stefan Wagner; Sabine Werres

    2017-01-01

    Studies have shown that nurseries are an important source for the spread of Phytophthora. Most surveys and studies focusing on the epidemiology of these pathogens in nurseries are based on sampling of symptomatic plants or on samples like water of different sources used for irrigation. There is little knowledge, however, on the survival and...

  18. Phytophthora Genome Sequences Uncover Evolutionary Origins and Mechanisms of Pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Lamour, Kurt H [ORNL; McDonald, W Hayes [ORNL; Savidor, Alon [ORNL

    2006-01-01

    Genome sequences of the soybean pathogen, Phytophthora sojae, and the sudden oak death pathogen, Phytophthora ramorum, suggest a photosynthetic past and reveal recent massive expansion and diversification of potential pathogenicity gene families. Abstract: Draft genome sequences of the soybean pathogen, Phytophthora sojae, and the sudden oak death pathogen, Phytophthora ramorum, have been determined. O mycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms and the presence of many Phytophthora genes of probable phototroph origin support a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors and, in particular, a superfamily of 700 proteins with similarity to known o mycete avirulence genes.

  19. Phytophthora Genome Sequences Uncover Evolutionary Origins and Mechanisms of Pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, Brett M.; Tripathy, Sucheta; Zhang, Xuemin; Dehal, Paramvir; Jiang, Rays H. Y.; Aerts, Andrea; Arredondo, Felipe D.; Baxter, Laura; Bensasson, Douda; Beynon, JIm L.; Chapman, Jarrod; Damasceno, Cynthia M. B.; Dorrance, Anne E.; Dou, Daolong; Dickerman, Allan W.; Dubchak, Inna L.; Garbelotto, Matteo; Gijzen, Mark; Gordon, Stuart G.; Govers, Francine; Grunwald, NIklaus J.; Huang, Wayne; Ivors, Kelly L.; Jones, Richard W.; Kamoun, Sophien; Krampis, Konstantinos; Lamour, Kurt H.; Lee, Mi-Kyung; McDonald, W. Hayes; Medina, Monica; Meijer, Harold J. G.; Nordberg, Erik K.; Maclean, Donald J.; Ospina-Giraldo, Manuel D.; Morris, Paul F.; Phuntumart, Vipaporn; Putnam, Nicholas J.; Rash, Sam; Rose, Jocelyn K. C.; Sakihama, Yasuko; Salamov, Asaf A.; Savidor, Alon; Scheuring, Chantel F.; Smith, Brian M.; Sobral, Bruno W. S.; Terry, Astrid; Torto-Alalibo, Trudy A.; Win, Joe; Xu, Zhanyou; Zhang, Hongbin; Grigoriev, Igor V.; Rokhsar, Daniel S.; Boore, Jeffrey L.

    2006-04-17

    Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oömycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oömycete avirulence genes.

  20. Different myrosinase and idioblast distribution in Arabidopsis and Brassica napus

    DEFF Research Database (Denmark)

    Andreasson, Erik; Jørgensen, Lise Bolt; Höglund, Anna-Stina

    2001-01-01

    Arabidopsis, Brassica napus, Myrosinase, Myrosinase Binding Protein, Glucosinolates, Myrosin Cell, Immunocytochemistry......Arabidopsis, Brassica napus, Myrosinase, Myrosinase Binding Protein, Glucosinolates, Myrosin Cell, Immunocytochemistry...

  1. User Guidelines for the Brassica Database: BRAD.

    Science.gov (United States)

    Wang, Xiaobo; Cheng, Feng; Wang, Xiaowu

    2016-01-01

    The genome sequence of Brassica rapa was first released in 2011. Since then, further Brassica genomes have been sequenced or are undergoing sequencing. It is therefore necessary to develop tools that help users to mine information from genomic data efficiently. This will greatly aid scientific exploration and breeding application, especially for those with low levels of bioinformatic training. Therefore, the Brassica database (BRAD) was built to collect, integrate, illustrate, and visualize Brassica genomic datasets. BRAD provides useful searching and data mining tools, and facilitates the search of gene annotation datasets, syntenic or non-syntenic orthologs, and flanking regions of functional genomic elements. It also includes genome-analysis tools such as BLAST and GBrowse. One of the important aims of BRAD is to build a bridge between Brassica crop genomes with the genome of the model species Arabidopsis thaliana, thus transferring the bulk of A. thaliana gene study information for use with newly sequenced Brassica crops.

  2. Pathogenicity of Phytophthora isolates originating from several woody hosts in Bulgaria and Poland

    Directory of Open Access Journals (Sweden)

    Lyubenova Aneta B.

    2016-09-01

    Full Text Available Our aim was to examine the virulence of eight Phytophthora isolates belonging to three species (Phytophthora cryptogea, Phytophthora plurivora and Phytophthora quercina obtained from diverse European ecosystems (in Bulgaria, Poland and Germany towards three forest tree hosts – English oak (Quercus robur L., Turkey oak (Quercus cerris L. and European beech (Fagus sylvatica L..

  3. Phytophthora megakarya : A potential threat to the cocoa industry in ...

    African Journals Online (AJOL)

    A severe black pod disease of cocoa in Ghana caused by Phytophthora megakarya was first reported in 1985, even though there is evidence that the fungus might have existed earlier. Until then, only Phytophthora palmivora which causes a less severe black pod disease was known in Ghana. P. megakarya has changed ...

  4. Low genetic diversity of Phytophthora infestans population in potato ...

    African Journals Online (AJOL)

    AJL

    genetic diversity of P. infestans and geographical origin. These results provided a foundation for making integrated control measures in the future. Key words: Phytophthora infestans, population genetics, simple-sequence repeat (SSR), potato late blight. INTRODUCTION. Phytophthora infestans (Mont.) de Bary, causing the ...

  5. Effects of ultraviolet radiation and temperature on the ultrastructure of zoospores of the brown macroalga Laminaria hyperborea.

    Science.gov (United States)

    Steinhoff, F S; Wiencke, C; Müller, R; Bischof, K

    2008-05-01

    The interactive effects of an 8 h exposure to UV radiation and altered temperatures on the ultrastructure and germination of zoospores of the sublittoral brown alga Laminaria hyperborea (Gunn.) Foslie were investigated for the first time. Spores were exposed to four temperatures (2, 7, 12 and 17 degrees C) and three light regimes (PAR, PAR + UV-A, PAR + UV-A+UV-B). Freshly-released spores of L. hyperborea lack a cell wall and contain a nucleus with fine granular nucleoplasm and a nucleolus, one chloroplast, several mitochondria, dictyosomes and an endoplasmatic reticulum. Further, several kinds of so-called adhesive vesicles, lipid globuli and physodes containing UV-absorbing phlorotannins are embedded in the cytoplasm. No eye-spot is present. Physodes were found but they were rare and small. After an 8 h exposure to UV-B, the nucleoplasm had a mottled structure, chloroplasts contained plastoglobuli, the structure of the mitochondria changed from crista- to sacculus-type and germination was strongly inhibited at all temperatures. UV-A only had an impact on the ultrastructure at the highest temperature tested. The strongest effects were found at 17 degrees C, where germination was reduced to 35%, 32% and 9% after exposure to PAR, PAR+UV-A and PAR + UV-A + UV-B, respectively. This study indicates that UV-B radiation has strong damaging effects on the physiology and ultrastructure of zoospores of L. hyperborea. The results are important for developing scenarios for the effect of enhanced UV radiation and increasing temperatures caused by global climate changes.

  6. Development of Phytophthora fruit rot caused by Phytophthora capsici on resistant and susceptible watermelon fruit of different ages

    Science.gov (United States)

    Watermelon is an important crop grown in 44 states in the United States. Phytophthora fruit rot caused by Phytophthora capsici is a serious disease in the southeastern U.S., where over 50% of the watermelons are produced. The disease has resulted in severe losses to watermelon growers, especially in...

  7. Monitoring for Phytophthora ramorum and other species of Phytophthora in nurseries and urban areas in the Southeastern USA

    Science.gov (United States)

    Yeshi A. Wamishe; Steven N. Jeffers; Jaesoon Hwang

    2008-01-01

    Nurseries in the southeastern United States that received ornamental plants in 2004 colonized by Phytophthora ramorum and the surrounding urban areas are being monitored to determine if this pathogen has escaped and become established. At the same time, the prevalence and diversity of other species of Phytophthora are being...

  8. Subgenome parallel selection is associated with morphotype diversification and convergent crop domestication in Brassica rapa and Brassica oleracea

    NARCIS (Netherlands)

    Cheng, Feng; Sun, Rifei; Hou, Xilin; Zheng, Hongkun; Zhang, Fenglan; Zhang, Yangyong; Liu, Bo; Liang, Jianli; Zhuang, Mu; Liu, Yunxia; Liu, Dongyuan; Wang, Xiaobo; Li, Pingxia; Liu, Yumei; Lin, Ke; Bucher, Johan; Zhang, Ningwen; Wang, Yan; Wang, Hui; Deng, Jie; Liao, Yongcui; Wei, Keyun; Zhang, Xueming; Fu, Lixia; Hu, Yunyan; Liu, Jisheng; Cai, Chengcheng; Zhang, Shujiang; Zhang, Shifan; Li, Fei; Zhang, Hui; Zhang, Jifang; Guo, Ning; Liu, Zhiyuan; Liu, Jin; Sun, Chao; Ma, Yuan; Zhang, Haijiao; Cui, Yang; Freeling, Micheal R.; Borm, Theo; Bonnema, Guusje; Wu, Jian; Wang, Xiaowu

    2016-01-01

    Brassica species, including crops such as cabbage, turnip and oilseed, display enormous phenotypic variation. Brassica genomes have all undergone a whole-genome triplication (WGT) event with unknown effects on phenotype diversification. We resequenced 199 Brassica rapa and 119 Brassica oleracea

  9. Variation in capsidiol sensitivity between Phytophthora infestans and Phytophthora capsici is consistent with their host range.

    Science.gov (United States)

    Giannakopoulou, Artemis; Schornack, Sebastian; Bozkurt, Tolga O; Haart, Dave; Ro, Dae-Kyun; Faraldos, Juan A; Kamoun, Sophien; O'Maille, Paul E

    2014-01-01

    Plants protect themselves against a variety of invading pathogenic organisms via sophisticated defence mechanisms. These responses include deployment of specialized antimicrobial compounds, such as phytoalexins, that rapidly accumulate at pathogen infection sites. However, the extent to which these compounds contribute to species-level resistance and their spectrum of action remain poorly understood. Capsidiol, a defense related phytoalexin, is produced by several solanaceous plants including pepper and tobacco during microbial attack. Interestingly, capsidiol differentially affects growth and germination of the oomycete pathogens Phytophthora infestans and Phytophthora capsici, although the underlying molecular mechanisms remain unknown. In this study we revisited the differential effect of capsidiol on P. infestans and P. capsici, using highly pure capsidiol preparations obtained from yeast engineered to express the capsidiol biosynthetic pathway. Taking advantage of transgenic Phytophthora strains expressing fluorescent markers, we developed a fluorescence-based method to determine the differential effect of capsidiol on Phytophtora growth. Using these assays, we confirm major differences in capsidiol sensitivity between P. infestans and P. capsici and demonstrate that capsidiol alters the growth behaviour of both Phytophthora species. Finally, we report intraspecific variation within P. infestans isolates towards capsidiol tolerance pointing to an arms race between the plant and the pathogens in deployment of defence related phytoalexins.

  10. The importin α subunit PsIMPA1 mediates the oxidative stress response and is required for the pathogenicity of Phytophthora sojae.

    Science.gov (United States)

    Yang, Xinyu; Ding, Fa; Zhang, Lei; Sheng, Yuting; Zheng, Xiaobo; Wang, Yuanchao

    2015-09-01

    The sensing of extracellular signals and their transduction into an appropriate response are crucial for the survival and virulence of plant pathogens. Eukaryotic plant pathogens must overcome the obstacles posed by nuclear membranes to manipulate gene expression to adapt to the host challenge. A highly sophisticated mechanism is the use of importins to transport proteins into the nucleus. In this study, we identified a conserved importin α gene, PsIMPA1, in Phytophthora sojae that was differentially expressed during the life cycle of this soybean pathogen. PsIMPA1 expression was lowest in zoospores and cysts but relatively consistent during the other life cycle stages, except for a slight increase at 6h post infection. Silenced mutants Psimpa1 had a decreased growth rate, an aberrant mycelial morphology, and a severely impaired ability to form oospores and sporangia. In addition, the Psimpa1 mutants exhibited reduced pathogenicity compared to the wild type. 3,3-Diaminobenzidine (DAB) staining and in vitro hydrogen peroxide tolerance assays showed that the scavenging of reactive oxygen species by these mutants was significantly impaired. Taken together, these results indicate that PsIMPA1 regulates multiple processes during the life cycle of P. sojae. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Genome sequences of six Phytophthora species associated with forests in New Zealand

    Science.gov (United States)

    Studholme, D.J.; McDougal, R.L.; Sambles, C.; Hansen, E.; Hardy, G.; Grant, M.; Ganley, R.J.; Williams, N.M.

    2015-01-01

    In New Zealand there has been a long association of Phytophthora diseases in forests, nurseries, remnant plantings and horticultural crops. However, new Phytophthora diseases of trees have recently emerged. Genome sequencing has been performed for 12 Phytophthora isolates, from six species: Phytophthora pluvialis, Phytophthora kernoviae, Phytophthora cinnamomi, Phytophthora agathidicida, Phytophthora multivora and Phytophthora taxon Totara. These sequences will enable comparative analyses to identify potential virulence strategies and ultimately facilitate better control strategies. This Whole Genome Shotgun data have been deposited in DDBJ/ENA/GenBank under the accession numbers LGTT00000000, LGTU00000000, JPWV00000000, JPWU00000000, LGSK00000000, LGSJ00000000, LGTR00000000, LGTS00000000, LGSM00000000, LGSL00000000, LGSO00000000, and LGSN00000000. PMID:26981359

  12. Phytophthora ramorum and Phytophthora gonapodyides differently colonize and contribute to decay of California bay laurel (Umbellularia californica) leaf litter in stream ecosystems

    Science.gov (United States)

    Kamyar Aram; David M. Rizzo

    2017-01-01

    The prevalence of Phytophthora species in surface waters has earned increasing attention in the past decades, in great part as a result of “stream monitoring” programs for detection and monitoring of Phytophthora ramorum and other invasive species. The potential for Phytophthora ...

  13. Management of chili pepper root rot and wilt (caused by Phytophthora nicotianae by grafting onto resistant rootstock

    Directory of Open Access Journals (Sweden)

    Mourad SAADOUN

    2013-05-01

    Full Text Available Root rot and plant wilting caused by Phytophthora nicotianae is a severe disease of chili pepper (Capsicum annuum L. in open fields and under greenhouse production in Tunisia. Chili pepper grafting for disease manage- ment is attracting increased interest in recent years. Using the tube grafting technique, different compatible scion/rootstock combinations were obtained with the wild-type pepper SCM334 and the local chili pepper cultivars ‘Beldi’ and ‘Baker’. SCM334 was resistant to P. nicotianae, while the cultivars Beldi and Baker were susceptible. Plant inoculations were performed with P. nicotianae zoospores, and severity of root rot was rated 30 days post- inoculation using a 0 (healthy plant to 5 (dead plant severity score. On SCM334 rootstock and with ‘Beldi’ or ‘Baker’ scions, the intensity of root rot was very low (mean score 0.1–0.2 and plants were healthy. However, with Baker or Beldi rootstocks and SCM334 scions, root rot was severe (mean score 3.1–4.6, leading to high numbers of wilting and dead plants. This severe root rot was similar to that observed on non-grafted plants of ‘Baker’ and ‘Beldi’ inoculated with the pathogen. Under greenhouse conditions, measurements of agronomic characters indicated non-consistent improvement of these features on the scion cultivar when SCM334 was the rootstock. Since plant foliage is not attacked by this pathogen, these results show that susceptible chili pepper scions grafted onto SCM334 rootstocks could be used for root rot management and improvement of pepper yields in P. nicotianae infested soils.

  14. Alleviation of Phytophthora capsici-induced oxidatıve stress by foliarly applied proline in Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Koç Esra

    2017-01-01

    Full Text Available Phytophthora capsici is a highly destructive pathogen of pepper. To examine whether proline modifies the levels of plant defense compounds produced in response to P. capsici-induced stress, pepper seedlings were infected with P. capsici-22 in the presence of proline (1 mM, 10 mM or in its absence. Proline was sprayed on the leaves of CM-334 and Kekova pepper cultivars prior to inoculation. CM-334 was more resistant to P. capsici-22, while the Kekova cultivar exhibited a sensitive reaction. P. capsici-22 increased the total phenolic compound and H2O2 levels, as well as phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase activities in pepper seedlings. The application of exogenous proline further increased the activities of phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase, as well as the total levels of phenolic compounds and the fresh and dry weights of the plants on the 5th and 7th days post treatment. After proline application, the highest catalase activity was found in both cultivars on the 5th day of the 10 mM proline + P. capsici application. On all days of the experiment, the applications caused a decrease in disease severity, necrosis length and H2O2 levels in both cultivars. In addition, proline decreased the colony growth of P. capsici and the number of zoospores. This finding indicates that enzymes and total phenolic compound levels protect the pepper seedlings against stress-related damage. Moreover, proline has the potential to directly scavenge free radicals and promote enzyme activity in pepper seedlings under P. capsici stress. These results suggest that foliar application of proline is an effective way to improve the stress tolerance of pepper to P. capsici.

  15. The effect of rumen ciliates on chitinolytic activity, chitin content and the number of fungal zoospores in the rumen fluid of sheep.

    Science.gov (United States)

    Miltko, Renata; Bełżecki, Grzegorz; Herman, Andrzej; Kowalik, Barbara; Skomiał, Jacek

    2016-12-01

    The objective of this study was to investigate the effect of selected protozoa on the degradation and concentration of chitin and the numbers of fungal zoospores in the rumen fluid of sheep. Three adult ewes were fed a hay-concentrate diet, defaunated, then monofaunated with Entodinium caudatum or Diploplastron affine alone and refaunated with natural rumen fauna. The average density of the protozoa population varied from 6.1 · 10(4) (D. affine) to 42.2 · 10(4) cells/ml rumen fluid (natural rumen fauna). The inoculation of protozoa in the rumen of defaunated sheep increased the total activity of chitinolytic enzymes from 2.9 to 3.6 μmol N-acetylglucosamine/g dry matter (DM) of rumen fluid per min, the chitin concentration from 6.3 to 7.2 mg/g DM of rumen fluid and the number of fungal zoospores from 8.1 to 10.9 · 10(5) cells/ml rumen fluid. All examined indices showed diurnal variations. Ciliate population density was highest immediately prior to feeding and lowest at 4 h thereafter. The opposite effects were observed for the numbers of fungal zoospores, the chitin concentration and chitinolytic activity. Furthermore, it was found that chitin from zoospores may account for up to 95% of total microbial chitin in the rumen fluid of sheep. In summary, the examined ciliate species showed the ability of chitin degradation as well as a positive influence on the development of the ruminal fungal population.

  16. PHYTOPHTHORA MEGAKARYA: A REVIEW ON ITS STATUS AS A ...

    African Journals Online (AJOL)

    ACSS

    2015-02-23

    Feb 23, 2015 ... broom, swollen shoot virus, vascular streak dieback, and monilia ..... evidence of alternative hosts of the pathogen. Phytophthora .... efficacy of fungicide treatment. ..... or derivatives thereof, reduced necrosis of cacao leaf discs ...

  17. Genetic diversity and relationships among cabbage ( Brassica ...

    African Journals Online (AJOL)

    The integration of our data with historical documents confirmed that traditional cabbage landraces cultivated in North of China were first introduced from Russia. Key words: Amplified fragment length polymorphism (AFLP), genetic diversity, cabbage (Brassica oleracea var. capitata), landraces, population structure.

  18. Managing Phytophthora crown and root rot on tomato by pre-plant treatments with biocontrol agents, resistance inducers, organic and mineral fertilizers under nursery conditions

    Directory of Open Access Journals (Sweden)

    Giovanna GILARDI

    2014-09-01

    Full Text Available Five trials were carried out under greenhouse conditions to test the efficacy of spray programmes based on biocontrol agents, phosphite-based fertilizers and a chemical inducer of resistance (acibenzolar-S-methyl, phosethyl-Al to control crown and root rot of tomato incited by Phytophthora nicotianae. The best disease control, under high disease pressure resulting from artificial inoculation, was obtained with three pre-plant leaf sprays at 7 d intervals with acibenzolar-S-methyl and with two mineral phosphite-based fertilizers. The disease reduction achieved was similar to that obtained with a single application of azoxystrobin and metalaxyl-M. Phosetyl-Al and the biocontrol agents Glomus spp. + Bacillus megaterium + Trichoderma, B. subtilis QST713, B. velezensis IT45 and the mixture T. asperellum ICC012 + T. gamsii ICC080 provided a partial disease control. Brassica carinata pellets did not control the disease.

  19. Phytophthora Species, New Threats to the Plant Health in Korea

    Directory of Open Access Journals (Sweden)

    Ik-Hwa Hyun

    2014-12-01

    Full Text Available Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries into Korea from 1900 to 2010. The genus Phytophthora, classified in oomycetes, includes more than 120 species that are mostly recognized worldwide as highly invasive plant pathogens. After 2000, over 50 new species of Phytophthora were identified internationally as plant pathogens occurring in crops and forest trees. In Korea, Phytophthora is also one of the most serious plant pathogens. To date, 22 species (about one-fifth of known species of the genus have been identified and reported as plant pathogens in the country. The likelihood of new exotic Phytophthora species being introduced into Korea continues to increase, thus necessitating intensive plant quarantine inspections. As new potential threats to plant health in Korea, six Phytophthora species, namely, P. alni, P. inundata, P. kernoviae, P. pinifolia, P. quercina, and P. ramorum, are discussed in this review with focus on history, disease, biology, management, and plant quarantine issues.

  20. Evaluation of Watermelon Germplasm for Resistance to Phytophthora Blight Caused by Phytophthora capsici

    Directory of Open Access Journals (Sweden)

    Min-Jeong Kim

    2013-03-01

    Full Text Available This study was conducted to determine the Phytophthora rot resistance of 514 accessions of watermelon germplasm, Citrullus lanatus var lanatus. About 46% of the 514 accessions tested were collections from Uzbekistan, Turkey, China, U.S.A., and Ukraine. Phytophthora capsici was inoculated to 45-day-old watermelon seedlings by drenching with 5 ml of sporangial suspension (10⁶ sporangia/ml. At 7 days after inoculation, 21 accessions showed no disease symptoms while 291 accessions of susceptible watermelon germplasm showed more than 60.1% disease severity. A total of 510 accessions of watermelon germplasm showed significant disease symptoms and were rated as susceptible to highly susceptible 35 days after inoculation. The highly susceptible watermelon germplasm exhibited white fungal hyphae on the lesion or damping off with water-soaked and browning symptoms. One accession (IT032840 showed moderate resistance and two accessions (IT185446 and IT187904 were resistant to P. capsici. Results suggest that these two resistant germplasm can be used as a rootstock and as a source of resistance in breeding resistant watermelon varieties against Phytophthora.

  1. Pathogenicity of Phytophthora species isolated from rhizosphere soil in the eastern United States

    Science.gov (United States)

    Y. Balci; S. Balci; W.L. MacDonald; K.W. Gottschalk

    2008-01-01

    Pathogenicity of seven Phytophthora species was assessed by inoculation of stem and foliar tissues of oak species (Quercus spp.) native to the eastern United States. Phytophthora cambivora, P. cinnamomi, P. citricola, P. europaea, P. quercina...

  2. Caractérisation des isolats de Phytophthora spp du verger ...

    African Journals Online (AJOL)

    SARAH

    31 oct. 2013 ... Characterization of Phytophthora spp isolates from cocoa orchard of Côte d'Ivoire ... cocoa black disease obtained in the main production areas of cocoa (East, Centre-West ...... Plant Pathogen Genus Phytophthora American.

  3. Oilseed brassica improvement: through induced mutations

    International Nuclear Information System (INIS)

    Shah, S.A.; Ali, I.; Rehman, K.

    1990-06-01

    The oilseed brassica improvement programme is discussed in this report. Some observations on different plant mutants were made throughout the growth period and results revealed that most of the selected mutants of both the varieties expressed better performance than the parent by showing superior plant traits. A new species named brassica carinata has tremendous untapped potential as an oilseed crop. Efforts for creating maximum variability in rapeseed mustard varieties by means other than gamma radiation continued. (A.B.)

  4. Mineral, vitamin C and crude protein contents in kale (Brassica ...

    African Journals Online (AJOL)

    ajl yemi

    2011-10-27

    Oct 27, 2011 ... Key words: Kale (Brassica oleracea var. acephala), harvesting stage, vitamin C, crude protein, mineral content. .... L-ascorbic acid (or vitamin C) in plant tissues. .... Cooking methods of Brassica rapa affect the preservation of.

  5. A review of the Phytophthora pod rot disease situation in Ghana ...

    African Journals Online (AJOL)

    The presence of Phytophthora megakarya, which until 1985 was unknown in Ghana, has changed the status of black pod disease of cocoa in the country. Hitherto, only Phytophthora palmivora was known to be present. This paper reviews the Phytophthora pod disease situation, the origin, distribution, incidence and ...

  6. 75 FR 44936 - Notice of Request for Extension of Approval of an Information Collection; Phytophthora Ramorum...

    Science.gov (United States)

    2010-07-30

    ...] Notice of Request for Extension of Approval of an Information Collection; Phytophthora Ramorum... interstate movement of regulated articles to prevent the spread of Phytophthora ramorum. DATES: We will... for the interstate movement of regulated articles to prevent the spread of Phytophthora ramorum...

  7. 40 CFR 180.1057 - Phytophthora palmivora; exemption from requirement of tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Phytophthora palmivora; exemption from... From Tolerances § 180.1057 Phytophthora palmivora; exemption from requirement of tolerance. Phytophthora palmivora is exempted from the requirement of a tolerance in or on the raw agricultural commodity...

  8. SSR marker variations in Brassica species provide insight into the origin and evolution of Brassica amphidiploids.

    Science.gov (United States)

    Thakur, Ajay Kumar; Singh, Kunwar Harendra; Singh, Lal; Nanjundan, Joghee; Khan, Yasin Jeshima; Singh, Dhiraj

    2018-01-01

    Oilseed Brassica represents an important group of oilseed crops with a long history of evolution and cultivation. To understand the origin and evolution of Brassica amphidiploids, simple sequence repeat (SSR) markers were used to unravel genetic variations in three diploids and three amphidiploid Brassica species of U's triangle along with Eruca sativa as an outlier. Of 124 Brassica-derived SSR loci assayed, 100% cross-transferability was obtained for B. juncea and three subspecies of B. rapa , while lowest cross-transferability (91.93%) was obtained for Eruca sativa . The average % age of cross-transferability across all the seven species was 98.15%. The number of alleles detected at each locus ranged from one to six with an average of 3.41 alleles per primer pair. Neighbor-Joining-based dendrogram divided all the 40 accessions into two main groups composed of B. juncea / B. nigra/B. rapa and B. carinata/B. napus/B. oleracea . C-genome of oilseed Brassica species remained relatively more conserved than A- and B-genome. A- genome present in B. juncea and B. napus seems distinct from each other and hence provides great opportunity for generating diversity through synthesizing amphidiploids from different sources of A- genome. B. juncea had least intra-specific distance indicating narrow genetic base. B. rapa appears to be more primitive species from which other two diploid species might have evolved. The SSR marker set developed in this study will assist in DNA fingerprinting of various Brassica species cultivars, evaluating the genetic diversity in Brassica germplasm, genome mapping and construction of linkage maps, gene tagging and various other genomics-related studies in Brassica species. Further, the evolutionary relationship established among various Brassica species would assist in formulating suitable breeding strategies for widening the genetic base of Brassica amphidiploids by exploiting the genetic diversity present in diploid progenitor gene pools.

  9. Mapping the Progression of Phytophthora Ramorum

    Science.gov (United States)

    Banh, T.; Li, J.; El-Askary, H. M.

    2013-12-01

    There has been a plant pathogen, Phytophthora Ramorum that has been causing trouble for the plant species in the forests of California and Oregon. Phytophthora is essentially a water mold that infects oak species like California black oak, coast live oak as well as California bay laurel (Lamsal). What this project aims to accomplish is to observe any changes in NDVI values between the years of 2002 and 1994. What the project hopes to observe is a decline of NDVI values between the two years because the infection of Phytophtora Ramorum will cause stress to the plant or kill the plant, which will lower the values of NDVI. The project will utilizes satellite data to create NDVI images over the study area and two types of change detection methods to observe the differences between the NDVI values of the two years. Preliminary results for the project, data obtained from Landsat 7 ETM+ with a resolution of 240 meters, was not able to observe any significant changes. A finer resolution to differentiate the NDVI values would be needed. In addition the best way to keep the pathogen from getting out of control is with ground level management, or complete eradication of the pathogen. These eradication methods include burning the infected host plants and spreading herbicide (Alexander). With that in mind it would be ideal to have an early detection of the pathogen infestation. Therefore another goal of the project is to continue to research if remote sensing could play a role in an early detection method for the presence of Phytophtora Ramorum.

  10. In vitro propagation of Ethiopian mustard ( Brassica carinata A ...

    African Journals Online (AJOL)

    Brassica carinata (A. Braun) is an amphi-diploid species that originated from interspecific hybridization between Brassica nigra and Brassica oleracea in the highlands of Ethiopia. The crop has many desirable agronomic traits but with oil quality constraints like high erucic acid and glucosinolate contents. In this study, two ...

  11. Tolerence of Braccica nigra to Pieris brassicae herbivory

    NARCIS (Netherlands)

    Blatt, S.E.; Smallegange, R.C.; Hess, L.; Harvey, J.A.; Dicke, D.; van Loon, J.J.A.

    2008-01-01

    Black mustard, Brassica nigra (L.) Koch, is a wild annual species found throughout Europe and fed on by larvae of the large cabbage-white butterfly, Pieris brassicae L. We examined the impact of herbivory from P. brassicae, a gregarious herbivore, on B. nigra grown from wild seed collected locally.

  12. BrassicaTED - a public database for utilization of miniature transposable elements in Brassica species.

    Science.gov (United States)

    Murukarthick, Jayakodi; Sampath, Perumal; Lee, Sang Choon; Choi, Beom-Soon; Senthil, Natesan; Liu, Shengyi; Yang, Tae-Jin

    2014-06-20

    MITE, TRIM and SINEs are miniature form transposable elements (mTEs) that are ubiquitous and dispersed throughout entire plant genomes. Tens of thousands of members cause insertion polymorphism at both the inter- and intra- species level. Therefore, mTEs are valuable targets and resources for development of markers that can be utilized for breeding, genetic diversity and genome evolution studies. Taking advantage of the completely sequenced genomes of Brassica rapa and B. oleracea, characterization of mTEs and building a curated database are prerequisite to extending their utilization for genomics and applied fields in Brassica crops. We have developed BrassicaTED as a unique web portal containing detailed characterization information for mTEs of Brassica species. At present, BrassicaTED has datasets for 41 mTE families, including 5894 and 6026 members from 20 MITE families, 1393 and 1639 members from 5 TRIM families, 1270 and 2364 members from 16 SINE families in B. rapa and B. oleracea, respectively. BrassicaTED offers different sections to browse structural and positional characteristics for every mTE family. In addition, we have added data on 289 MITE insertion polymorphisms from a survey of seven Brassica relatives. Genes with internal mTE insertions are shown with detailed gene annotation and microarray-based comparative gene expression data in comparison with their paralogs in the triplicated B. rapa genome. This database also includes a novel tool, K BLAST (Karyotype BLAST), for clear visualization of the locations for each member in the B. rapa and B. oleracea pseudo-genome sequences. BrassicaTED is a newly developed database of information regarding the characteristics and potential utility of mTEs including MITE, TRIM and SINEs in B. rapa and B. oleracea. The database will promote the development of desirable mTE-based markers, which can be utilized for genomics and breeding in Brassica species. BrassicaTED will be a valuable repository for scientists

  13. The aspartic proteinase family of three Phytophthora species

    Science.gov (United States)

    2011-01-01

    Background Phytophthora species are oomycete plant pathogens with such major social and economic impact that genome sequences have been determined for Phytophthora infestans, P. sojae and P. ramorum. Pepsin-like aspartic proteinases (APs) are produced in a wide variety of species (from bacteria to humans) and contain conserved motifs and landmark residues. APs fulfil critical roles in infectious organisms and their host cells. Annotation of Phytophthora APs would provide invaluable information for studies into their roles in the physiology of Phytophthora species and interactions with their hosts. Results Genomes of Phytophthora infestans, P. sojae and P. ramorum contain 11-12 genes encoding APs. Nine of the original gene models in the P. infestans database and several in P. sojae and P. ramorum (three and four, respectively) were erroneous. Gene models were corrected on the basis of EST data, consistent positioning of introns between orthologues and conservation of hallmark motifs. Phylogenetic analysis resolved the Phytophthora APs into 5 clades. Of the 12 sub-families, several contained an unconventional architecture, as they either lacked a signal peptide or a propart region. Remarkably, almost all APs are predicted to be membrane-bound. Conclusions One of the twelve Phytophthora APs is an unprecedented fusion protein with a putative G-protein coupled receptor as the C-terminal partner. The others appear to be related to well-documented enzymes from other species, including a vacuolar enzyme that is encoded in every fungal genome sequenced to date. Unexpectedly, however, the oomycetes were found to have both active and probably-inactive forms of an AP similar to vertebrate BACE, the enzyme responsible for initiating the processing cascade that generates the Aβ peptide central to Alzheimer's Disease. The oomycetes also encode enzymes similar to plasmepsin V, a membrane-bound AP that cleaves effector proteins of the malaria parasite Plasmodium falciparum during

  14. Ozone affects growth and development of Pieris brassicae on the wild host plant Brassica nigra

    International Nuclear Information System (INIS)

    Khaling, Eliezer; Papazian, Stefano; Poelman, Erik H.; Holopainen, Jarmo K.; Albrectsen, Benedicte R.; Blande, James D.

    2015-01-01

    When plants are exposed to ozone they exhibit changes in both primary and secondary metabolism, which may affect their interactions with herbivorous insects. Here we investigated the performance and preferences of the specialist herbivore Pieris brassicae on the wild plant Brassica nigra under elevated ozone conditions. The direct and indirect effects of ozone on the plant-herbivore system were studied. In both cases ozone exposure had a negative effect on P. brassicae development. However, in dual-choice tests larvae preferentially consumed plant material previously fumigated with the highest concentration tested, showing a lack of correlation between larval preference and performance on ozone exposed plants. Metabolomic analysis of leaf material subjected to combinations of ozone and herbivore-feeding, and focussing on known defence metabolites, indicated that P. brassicae behaviour and performance were associated with ozone-induced alterations to glucosinolate and phenolic pools. - Highlights: • We examined the effects of ozone on Pieris brassicae performance and preference. • We studied ozone and herbivore induced changes in the metabolome of Brassica nigra. • The performance of P. brassicae did not correlate with preference of ozonated plants. • Ozone and herbivore-feeding stress changes the phytochemical pools of B. nigra. - Ozone indirectly reduces herbivore performance, which is associated with change in phytochemical pools, but does not correlate with host plant preference

  15. INFLUENCIA DE LAS CONDICIONES DE INCUBACIÓN SOBRE LA ACTIVACIÓN DE ZOOSPORAS DE Spongospora subterranea, EN BUSCA DE UN INÓCULO PARA EL ESTUDIO DE LA SARNA POLVOSA INFLUENCE OF INCUBATION CONDITIONS ON THE ACTIVATION OF ZOOSPORES OF Spongospora subterranea, SEARCHING FOR AN INOCULUM TO THE STUDY OF THE POWDERY SCAB

    Directory of Open Access Journals (Sweden)

    Edgar Beltrán Sánchez

    2009-12-01

    Full Text Available La sarna polvosa es una enfermedad que decrece la producción de papa. Es causada por el parásito obligado Spongospora subterranea f. sp. subterranea, el cual produce grupos de zoosporas enquistadas llamados quistosoros. Cuando las zoosporas están activas pueden infectar raíces y tubérculos iniciando un nuevo ciclo reproductivo. Para estudiar la influencia de las condiciones de incubación sobre la activación de las zoosporas, suspensiones acuosas de quistosoros fueron incubadas bajo diferentes condiciones. Los quistosoros y las zoosporas activas fueron diariamente contados utilizando microscopio óptico. El mayor número de zoosporas activas se encontró al cuarto día de incubación, mientras que el menor número de quistosoros se registró al quinto día de incubación. Esto sugiere que las zoosporas permanecen activas por un corto periodo. El número de zoosporas activas por quistosoro fue significativamente (PThe powdery scab is a disease that decreases potato production. It is caused by Spongospora subterranea f. sp. subterranea. This obligate parasite produces cystosori, which are groups of encysted zoospores. When these zoospores are active, they can infect roots and tubers initiating a new replication cycle. To investigate the influence of the incubation conditions on the zoospore activation, suspensions of cystosori in water were incubated under different conditions. The cystosori and the active zoospores were daily counted under microscope. The higher number of active zoospores was found after four days of incubation, meanwhile the lower number of cystosori was found after five days of incubation. This suggests that zoospores are active for a short period. The number of active zoospores per cystosorus was significantly (P<0.05 higher in tap water than in distillated water, and in presence of light than in dark. More zoospores per cystosorus were activated at 19 °C than at 5 °C, but potato roots did not have a significant (P<0

  16. Standardized gene nomenclature for the Brassica genus

    Directory of Open Access Journals (Sweden)

    King Graham J

    2008-05-01

    Full Text Available Abstract The genus Brassica (Brassicaceae, Brassiceae is closely related to the model plant Arabidopsis, and includes several important crop plants. Against the background of ongoing genome sequencing, and in line with efforts to standardize and simplify description of genetic entities, we propose a standard systematic gene nomenclature system for the Brassica genus. This is based upon concatenating abbreviated categories, where these are listed in descending order of significance from left to right (i.e. genus – species – genome – gene name – locus – allele. Indicative examples are provided, and the considerations and recommendations for use are discussed, including outlining the relationship with functionally well-characterized Arabidopsis orthologues. A Brassica Gene Registry has been established under the auspices of the Multinational Brassica Genome Project that will enable management of gene names within the research community, and includes provisional allocation of standard names to genes previously described in the literature or in sequence repositories. The proposed standardization of Brassica gene nomenclature has been distributed to editors of plant and genetics journals and curators of sequence repositories, so that it can be adopted universally.

  17. Unleashing the genome of Brassica rapa

    Directory of Open Access Journals (Sweden)

    Haibao eTang

    2012-07-01

    Full Text Available The completion and release of the Brassica rapa genome is of great benefit to researchers of the Brassicas, Arabidopsis, and genome evolution. While its lineage is closely related to the model organism Arabidopsis thaliana, the Brassicas experienced a whole genome triplication subsequent to their divergence. This event contemporaneously created three copies of its ancestral genome, which had diploidized through the process of homeologous gene loss known as fractionation. By the fractionation of homeologous gene content and genetic regulatory binding sites, Brassica’s genome is well placed to use comparative genomic techniques to identify syntenic regions, homeologous gene duplications, and putative regulatory sequences. Here, we use the comparative genomics platform CoGe to perform several different genomic analyses with which to study structural changes of its genome and dynamics of various genetic elements. Starting with whole genome comparisons, the Brassica paleohexaploidy is characterized, syntenic regions with Arabidopsis thaliana are identified, and the TOC1 gene in the circadian rhythm pathway from Arabidopsis thaliana is used to find duplicated orthologs in Brassica rapa. These TOC1 genes are further analyzed to identify conserved noncoding sequences that contain cis-acting regulatory elements and promoter sequences previously implicated in circadian rhythmicity. Each 'cookbook style' analysis includes a step-by-step walkthrough with links to CoGe to quickly reproduce each step of the analytical process.

  18. Occurrence of Xanthomonas campestris pv. campestris (Pammel, 1895) Dowson 1939, on brassicas in Montenegro

    OpenAIRE

    Radunović Dragana; Balaž Jelica

    2012-01-01

    Brassicas form the most important group of vegetable crops in Montenegro. The cabbage (Brassica oleracea var. capitata) is most commonly grown, although other brassicas, particularly kale, Brussels sprout, cauliflower and broccoli, have been increasingly produced since recently. One of the specialties of vegetable production in Montenegro is growing of collard (Brassica oleracea var. acephala), which is the simplest variety of the Brassica oleracea species ...

  19. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici.

    Science.gov (United States)

    Sang, Mee Kyung; Shrestha, Anupama; Kim, Du-Yeon; Park, Kyungseok; Pak, Chun Ho; Kim, Ki Deok

    2013-06-01

    We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

  20. Distribution of Phytophthora spp. in Field Soils Determined by Immunoassay.

    Science.gov (United States)

    Miller, S A; Madden, L V; Schmitthenner, A F

    1997-01-01

    ABSTRACT Populations of Phytophthora spp. were determined by enzyme-linked immunosorbent assay (ELISA) in field soils used for pepper and soybean production in Ohio. Soybean fields were sampled extensively (64 fields, n = 6 samples per field over 2 years) and intensively (4 fields, n = 64 samples per field in 1 year) to assess heterogeneity of P. sojae populations. Four pepper fields (n = 64), three of which had a history of Phytophthora blight (caused by P. capsici), also were sampled intensively during a 6-month period. Mean (m), variance (v), and measures of aggregation (e.g., variance-to-mean ratio [v/m]) of immunoassay values, translated to Phytophthora antigen units (PAU), were related to the disease history in each of the pepper and soybean fields. Mean PAU values for fields in which Phytophthora root rot (soybean) or blight (pepper) had been moderate to severe were higher than in fields in which disease incidence had been low or not observed. A detection threshold value of 11.3 PAU was calculated with values for 64 samples from one pepper field, all of which tested negative for Phytophthora by bioassay and ELISA. Seven of the eight intensively sampled fields contained at least some detectable Phytophthora propagules, with the percentage of positive samples ranging from 1.6 to 73.4. Mean PAU values ranged from 1 to 84 (extensive soybean field sampling), 6 to 24 (intensive soybean field sampling), and 4 to 30 (intensive pepper field sampling); however, variances ranged from 0 to 7,774 (extensive sampling), 30 to 848 (intensive soybean field sampling), and 5 to 2,401 (intensive pepper field sampling). Heterogeneity of PAU was high in most individual soybean and pepper fields, with values of v/m greater than 1, and log(v) increasing with log(m), with a slope of about 2.0. Spatial autocorrelation coefficients were not significant, indicating there was no relationship of PAU values in neighboring sampling units (i.e., field locations) of the intensively sampled

  1. Phytophthora infestans population structure: A worldwide scale

    International Nuclear Information System (INIS)

    Cardenas, Martha; Danies, Giovanna; Tabima, Javier; Bernal, Adriana; Restrepo, Silvia

    2012-01-01

    Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of the pathogen's population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase) and Pep (Pep tidase), the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America, expanding it on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  2. Phytophthora infestans population structure: a worldwide scale

    Directory of Open Access Journals (Sweden)

    Martha Cárdenas Toquica

    2012-05-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep (Peptidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and the mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America expanding on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  3. Complete mitochondrial genome sequence of black mustard (Brassica nigra; BB) and comparison with Brassica oleracea (CC) and Brassica carinata (BBCC).

    Science.gov (United States)

    Yamagishi, Hiroshi; Tanaka, Yoshiyuki; Terachi, Toru

    2014-11-01

    Crop species of Brassica (Brassicaceae) consist of three monogenomic species and three amphidiploid species resulting from interspecific hybridizations among them. Until now, mitochondrial genome sequences were available for only five of these species. We sequenced the mitochondrial genome of the sixth species, Brassica nigra (nuclear genome constitution BB), and compared it with those of Brassica oleracea (CC) and Brassica carinata (BBCC). The genome was assembled into a 232 145 bp circular sequence that is slightly larger than that of B. oleracea (219 952 bp). The genome of B. nigra contained 33 protein-coding genes, 3 rRNA genes, and 17 tRNA genes. The cox2-2 gene present in B. oleracea was absent in B. nigra. Although the nucleotide sequences of 52 genes were identical between B. nigra and B. carinata, the second exon of rps3 showed differences including an insertion/deletion (indel) and nucleotide substitutions. A PCR test to detect the indel revealed intraspecific variation in rps3, and in one line of B. nigra it amplified a DNA fragment of the size expected for B. carinata. In addition, the B. carinata lines tested here produced DNA fragments of the size expected for B. nigra. The results indicate that at least two mitotypes of B. nigra were present in the maternal parents of B. carinata.

  4. Brassica villosa, a system for studying non-glandular trichomes and genes in the Brassicas.

    Science.gov (United States)

    Nayidu, Naghabushana K; Tan, Yifang; Taheri, Ali; Li, Xiang; Bjorndahl, Trent C; Nowak, Jacek; Wishart, David S; Hegedus, Dwayne; Gruber, Margaret Y

    2014-07-01

    Brassica villosa is a wild Brassica C genome species with very dense trichome coverage and strong resistance to many insect pests of Brassica oilseeds and vegetables. Transcriptome analysis of hairy B. villosa leaves indicated higher expression of several important trichome initiation genes compared with glabrous B. napus leaves and consistent with the Arabidopsis model of trichome development. However, transcripts of the TRY inhibitory gene in hairy B. villosa were surprisingly high relative to B. napus and relative transcript levels of SAD2, EGL3, and several XIX genes were low, suggesting potential ancillary or less important trichome-related roles for these genes in Brassica species compared with Arabidopsis. Several antioxidant, calcium, non-calcium metal and secondary metabolite genes also showed differential expression between these two species. These coincided with accumulation of two alkaloid-like compounds, high levels of calcium, and other metals in B. villosa trichomes that are correlated with the known tolerance of B. villosa to high salt and the calcium-rich natural habitat of this wild species. This first time report on the isolation of large amounts of pure B. villosa trichomes, on trichome content, and on relative gene expression differences in an exceptionally hairy Brassica species compared with a glabrous species opens doors for the scientific community to understand trichome gene function in the Brassicas and highlights the potential of B. villosa as a trichome research platform.

  5. Developing a taxonomic identification system of Phytophthora species based on microsatellites.

    Science.gov (United States)

    del Castillo-Múnera, Johanna; Cárdenas, Martha; Pinzón, Andrés; Castañeda, Adriana; Bernal, Adriana J; Restrepo, Silvia

    2013-01-01

    Phytophthora is the most important genus of the Oomycete plant pathogens. Nowadays, there are 117 described species in this genus, most of them being primary invaders of plant tissues. The different species are causal agents of diseases in a wide range of crops and plants in natural environments. In order to develop control strategies against Phytophthoraspecies, it is important to know the biology, ecology and evolutionary processes of these important pathogens. The aim of this study was to propose and validate a low cost identification system for Phytophthora species based on a set of polymorphic microsatellite (SSRs) markers. Thirty-three isolates representing Phytophthora infestans, Phytophthora andina, Phytophthora sojae, Phytophthora cryptogea, Phytophthora nicotianae, Phytophthora capsici and Phytophthora cinnamomi species were obtained, and 13 SSRs were selected as potentially transferable markers between these species. Amplification conditions, including annealing temperatures, were standardized for several markers. A subset of these markers amplified in all species, showing species-specific alleles. The adaptability and impact of the identification system in Colombia, an Andean agricultural country where different Phytophthora species co-exist in the same or in several hosts grown together, are discussed. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  6. New role for Cdc14 phosphatase: localization to basal bodies in the oomycete phytophthora and its evolutionary coinheritance with eukaryotic flagella.

    Directory of Open Access Journals (Sweden)

    Audrey M V Ah-Fong

    Full Text Available Cdc14 protein phosphatases are well known for regulating the eukaryotic cell cycle, particularly during mitosis. Here we reveal a distinctly new role for Cdc14 based on studies of the microbial eukaryote Phytophthora infestans, the Irish potato famine agent. While Cdc14 is transcribed constitutively in yeast and animal cells, the P. infestans ortholog is expressed exclusively in spore stages of the life cycle and not in vegetative hyphae where the bulk of mitosis takes place. PiCdc14 expression is first detected in nuclei at sporulation, and during zoospore formation the protein accumulates at the basal body, which is the site from which flagella develop. The association of PiCdc14 with basal bodies was supported by co-localization studies with the DIP13 basal body protein and flagellar β-tubulin, and by demonstrating the enrichment of PiCdc14 in purified flagella-basal body complexes. Overexpressing PiCdc14 did not cause defects in growth or mitosis in hyphae, but interfered with cytoplasmic partitioning during zoosporogenesis. This cytokinetic defect might relate to its ability to bind microtubules, which was shown using an in vitro cosedimentation assay. The use of gene silencing to reveal the precise function of PiCdc14 in flagella is not possible since we showed previously that silencing prevents the formation of the precursor stage, sporangia. Nevertheless, the association of Cdc14 with flagella and basal bodies is consistent with their phylogenetic distribution in eukaryotes, as species that lack the ability to produce flagella generally also lack Cdc14. An ancestral role of Cdc14 in the flagellar stage of eukaryotes is thereby proposed.

  7. Genome-wide prediction and functional validation of promoter motifs regulating gene expression in spore and infection stages of Phytophthora infestans.

    Directory of Open Access Journals (Sweden)

    Sourav Roy

    2013-03-01

    Full Text Available Most eukaryotic pathogens have complex life cycles in which gene expression networks orchestrate the formation of cells specialized for dissemination or host colonization. In the oomycete Phytophthora infestans, the potato late blight pathogen, major shifts in mRNA profiles during developmental transitions were identified using microarrays. We used those data with search algorithms to discover about 100 motifs that are over-represented in promoters of genes up-regulated in hyphae, sporangia, sporangia undergoing zoosporogenesis, swimming zoospores, or germinated cysts forming appressoria (infection structures. Most of the putative stage-specific transcription factor binding sites (TFBSs thus identified had features typical of TFBSs such as position or orientation bias, palindromy, and conservation in related species. Each of six motifs tested in P. infestans transformants using the GUS reporter gene conferred the expected stage-specific expression pattern, and several were shown to bind nuclear proteins in gel-shift assays. Motifs linked to the appressoria-forming stage, including a functionally validated TFBS, were over-represented in promoters of genes encoding effectors and other pathogenesis-related proteins. To understand how promoter and genome architecture influence expression, we also mapped transcription patterns to the P. infestans genome assembly. Adjacent genes were not typically induced in the same stage, including genes transcribed in opposite directions from small intergenic regions, but co-regulated gene pairs occurred more than expected by random chance. These data help illuminate the processes regulating development and pathogenesis, and will enable future attempts to purify the cognate transcription factors.

  8. Brassica rapa L. seed development in hypergravity

    NARCIS (Netherlands)

    Musgrave, M.E.; Kuang, A.; Allen, J.; Blasiak, J.; van Loon, J.J.W.A.

    2009-01-01

    Previous experiments had shown that microgravity adversely affected seed development in Brassica rapa L. We tested the hypothesis that gravity controls seed development via modulation of gases around the developing seeds, by studying how hypergravity affects the silique microenvironment and seed

  9. Development and application of qPCR and RPA genus and species-specific detection of Phytophthora sojae and Phytophthora sansomeana root rot pathogens of soybean

    Science.gov (United States)

    Phytophthora root rot of soybean, caused by Phytophthora sojae is one of the most important diseases in the Midwest US, causing losses of up to 44 million bushels per year. Disease may also be caused by P. sansomeana, however the prevalence and damage caused by this species is not well known, partl...

  10. A unique species in Phytophthora clade 10, Phytophthora intercalaris sp. nov., recovered from stream and irrigation water in the eastern USA

    Science.gov (United States)

    Balci, Y.; Brazee, N. J.; Loyd, A. L.; Hong, C. X.

    2016-01-01

    A novel species of the genus Phytophthora was recovered during surveys of stream and nursery irrigation water in Maryland, Massachusetts, North Carolina, Virginia and West Virginia in the USA. The novel species is heterothallic, and all examined isolates were A1 mating type. It produced rare ornamented oogonia and amphigynous antheridia when paired with A2 mating type testers of Phytophthora cinnamomi and Phytophthora cryptogea. Sporangia of this novel species were non-papillate and non-caducous. Thin-walled intercalary chlamydospores were abundant in hemp seed agar and carrot agar, while they were produced only rarely in aged cultures grown in clarified V8 juice agar. Phylogenetic analyses based on sequences of the internal transcribed spacer region and the β-tubulin and mitochondrial cytochrome-c oxidase 1 (cox1) genes indicated that the novel species is phylogenetically close to Phytophthora gallica in Phytophthora clade 10. The novel species has morphological and molecular features that are distinct from those of other species in Phytophthora clade 10. It is formally described here as Phytophthora intercalaris sp. nov. Description of this unique clade-10 species is important for understanding the phylogeny and evolution of Phytophthora clade 10. PMID:26620125

  11. The current situation with Phytophthora ramorum in England and Wales

    Science.gov (United States)

    David Slawson; Lynne Bennett; Nicola Parry; Charles Lane

    2006-01-01

    Since the first finding of Phytophthora ramorum in England in April 2002, an intensive campaign, supported by the European Community (EC) and national legislation, has been conducted to locate and eradicate all interceptions and outbreaks of P. ramorum. A summary of the findings made during these surveys is presented, along with an...

  12. Factors Affecting Onset of Sporulation in Phytophthora ramorum

    Science.gov (United States)

    To elucidate the sporulation potential of the sudden oak death pathogen, Phytophthora ramorum, on rhododendron, we conducted a series of experiments looking at the relationship between moisture period, lesion size, and onset of sporangia production. Inoculations were performed using P. ramorum isol...

  13. Phytophthora ramorum detection surveys for forests in the United States

    Science.gov (United States)

    S. W. Oak; W. D. Smith; B.M. Tkacz

    2006-01-01

    Diseases caused by Phytophthora ramorum in forest landscapes of North America are presently confined to areas of the Pacific coast in the states of CA and OR. However, the vulnerability of other ecosystems is suggested by the discovery in Europe and the U.K. of disease in hosts which are abundant in oak-dominated ecosystems of eastern North America;...

  14. Chemistry of coast live oak response to Phytophthora ramorum infection

    Science.gov (United States)

    Frances S. Ockels; Alieta Eyles; Brice A. McPherson; David L. Wood; Pierluigi Bonello

    2008-01-01

    Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant to the pathogen. The apparent resistance to P....

  15. Consequences of Phytophthora ramorum infection in coast live oaks

    Science.gov (United States)

    Brice McPherson; David L. Wood; Sylvia R. Mori; Pavel Svihra; Richard B. Standiford; N. Maggi. Kelly

    2008-01-01

    Sudden oak death, caused by Phytophthora ramorum, has infected and killed large numbers of oaks (Quercus spp.) and tanoaks (Lithocarpus densiflorus) in California since the mid 1990s. Since March 2000 we have been investigating the interactions between patterns of disease progression and...

  16. Reduced efficacy of fluazinam against Phytophthora infestans in the Netherlands

    NARCIS (Netherlands)

    Schepers, H.T.A.M.; Kessel, G.J.T.; Lucca, F.; Förch, M.G.; Den Bosch, van G.B.M.; Topper, C.G.; Evenhuis, A.

    2018-01-01

    Phytophthora infestans is the causal organism of potato late blight, the most important disease in potato, the second most important arable crop in Europe. The P. infestans population in Europe is well known for its sudden changes in composition. Currently it is composed of a wide variety of

  17. Interactions between biosurfactant-producing Pseudomonas and Phytophthora species

    NARCIS (Netherlands)

    Tran, H.

    2007-01-01

    Fluorescent Pseudomonas bacteria produce a wide variety of antimicrobial metabolites, including soap-like compounds referred to as biosurfactants. The results of this thesis showed that biosurfactant-producing Pseudomonas bacteria are effective in controlling Phytophthora foot rot

  18. Evolutionary relationships within the Phytophthora cactorum species complex in Europe.

    Science.gov (United States)

    Pánek, Matěj; Fér, Tomáš; Mráček, Jaroslav; Tomšovský, Michal

    2016-01-01

    The Phytophthora cactorum species complex in Europe is composed of P. cactorum, Phytophthora hedraiandra, and a hybrid species Phytophthora × serendipita. Evolutionary analyses using the amplified fragment length polymorphism (AFLP) method were carried out on 133 isolates from 19 countries. The AFLP data were complemented by sequence analysis of three genes (ITS region of ribosomal RNA gene, phenolic acid decarboxylase - Pheca I, and Cytochrome oxidase - Cox I), morphometric analysis and cardinal temperature data. The high proportion of clonal genotypes, low gene flow among groups, which was defined by the structure analysis, and low Nei's gene diversity confirms the homothallic life cycle of the groups. On the other hand, the ITS, Cox I and Pheca I sequence data support occasional hybridization between species. The structure K = 5 grouping revealed two groups of hybrid origin (C2 and F). While the C2 group resembles P. × serendipita, the F group includes Finnish isolates characterized by high oogonial abortion rates and slow growth. The morphological characters routinely used in identification of Phytophthora species are not useful for delimitation of species from the P. cactorum complex. Therefore, we discuss the status of P. hedraiandra as a separate species. The epitypification of P. cactorum is proposed. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  19. Field management of Phytophthora blight disease of cocoyam ...

    African Journals Online (AJOL)

    Cocoyam (Colocasia esculenta L). is an important edible tuber crop, but taro leaf blight caused by Phytophthora colocasiae has been the greatest constraint to cocoyam production in Nigeria since 2009. Field trials were conducted to determine the effect of fungicides and the spray regimes on leaf growth, disease incidence, ...

  20. Carbohydrate-related enzymes of important Phytophthora plant pathogens.

    Science.gov (United States)

    Brouwer, Henk; Coutinho, Pedro M; Henrissat, Bernard; de Vries, Ronald P

    2014-11-01

    Carbohydrate-Active enZymes (CAZymes) form particularly interesting targets to study in plant pathogens. Despite the fact that many CAZymes are pathogenicity factors, oomycete CAZymes have received significantly less attention than effectors in the literature. Here we present an analysis of the CAZymes present in the Phytophthora infestans, Ph. ramorum, Ph. sojae and Pythium ultimum genomes compared to growth of these species on a range of different carbon sources. Growth on these carbon sources indicates that the size of enzyme families involved in degradation of cell-wall related substrates like cellulose, xylan and pectin is not always a good predictor of growth on these substrates. While a capacity to degrade xylan and cellulose exists the products are not fully saccharified and used as a carbon source. The Phytophthora genomes encode larger CAZyme sets when compared to Py. ultimum, and encode putative cutinases, GH12 xyloglucanases and GH10 xylanases that are missing in the Py. ultimum genome. Phytophthora spp. also encode a larger number of enzyme families and genes involved in pectin degradation. No loss or gain of complete enzyme families was found between the Phytophthora genomes, but there are some marked differences in the size of some enzyme families. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. A Surface Plasmon Resonance Immunobiosensor for Detection of Phytophthora infestans

    DEFF Research Database (Denmark)

    Skottrup, Peter; Frøkiær, Hanne; Hejgaard, Jørn

    2006-01-01

    In this study we focused on the development of a Surface Plasmon Resonance (SPR) immunosensor for Phytophthora infestans detection. The fungus-like organism is the cause of potato late blight and is a major problem in potato growing regions of the world. Efficient control is dependent on early...

  2. Recovery of Phytophthora ramorum in plant tissue with mixed infections

    Science.gov (United States)

    This study was performed to investigate the frequency with which P. ramorum would be isolated from host tissue co-infected with P. ramorum as well as an indigenous Phytophthora species or P. kernoviae. Three separate experiments were tested in a similar manner using different combinations of pathog...

  3. Genetic transformation of Phytophthora ramorum with the jellyfish GFP gene

    Science.gov (United States)

    G. Calmin; M. Riedel; L. Belbahri; S. Wagner; S. Werres; F. Lefort

    2009-01-01

    The important quarantine organism Phytophthora ramorum has been dramatically increasing its host range in the past years and most of the studies concerning P. ramorum focus on these issues. Very little is known about the latency period. For sampling and analyzing potentially infected plant material,...

  4. Gene expression in the tanoak-Phytophthora ramorum interaction

    Science.gov (United States)

    Katherine J. Hayden; Matteo Garbelotto; Hardeep Fai; Brian Knaus; Richard Cronn; Jessica W. Wright

    2012-01-01

    Disease processes are dynamic, involving a suite of gene expression changes in both the host and the pathogen, all within a single tissue. As such, they lend themselves well to transcriptomic analysis. Here we focus on a generalist invasive pathogen (Phytophthora ramorum) and its most susceptible California Floristic Province native host, tanoak (...

  5. Monitoring Phytophthora ramorum distribution in streams within California watersheds

    Science.gov (United States)

    S.K. Murphy; C. Lee; Y. Valachovic; J. Bienapfl; W. Mark; A. Jirka; D.R. Owen; T.F. Smith; D.M. Rizzo

    2008-01-01

    One hundred-thirteen sites were established in perennial watercourses and sampled for 1 to 3 years between 2004 and 2006 to monitor for presence of Phytophthora ramorum throughout coastal central and northern California watersheds as well as portions of the Sierra Nevada mountain range (Murphy and others 2006). The majority of the monitored...

  6. Susceptibility of Australian plant species to Phytophthora ramorum

    Science.gov (United States)

    Kylie Ireland; Daniel H& uuml; berli; Bernard Dell; Ian Smith; David Rizzo; Giles. Hardy

    2010-01-01

    Phytophthora ramorum is an invasive plant pathogen causing considerable and widespread damage in nurseries, gardens, and natural woodland ecosystems of the United States and Europe, and is classified as a Category 1 pest in Australia. It is of particular interest to Australian plant biosecurity as, like P. cinnamomi; it has...

  7. Validation of a tuber blight (Phytophthora infestans) prediction model

    Science.gov (United States)

    Potato tuber blight caused by Phytophthora infestans accounts for significant losses in storage. There is limited published quantitative data on predicting tuber blight. We validated a tuber blight prediction model developed in New York with cultivars Allegany, NY 101, and Katahdin using independent...

  8. Phytophthora stricta isolated from Rhododendron maximum in Pennsylvania

    Science.gov (United States)

    During a survey in October 2013, in the Michaux State Forest in Pennsylvania , necrotic Rhododendron maximum leaves were noticed on mature plants alongside a stream. Symptoms were nondescript necrotic lesions at the tips of mature leaves. Colonies resembling a Phytophthora sp. were observed from c...

  9. The biology of Phytophthora infestans at its center of origin

    NARCIS (Netherlands)

    Grünwald, N.J.; Flier, W.G.

    2005-01-01

    The central highlands of Mexico are considered to be a center of genetic diversity for both the potato late blight pathogen and for tuber-bearing Solanum spp. Recent work conducted in Mexico and South America sheds new light on the biology and evolution of Phytophthora infestans and other related

  10. Molecular analysis of Phytophthora species found in Poland

    Directory of Open Access Journals (Sweden)

    Oszako Tomasz

    2017-12-01

    Full Text Available Pathogens of Phytophthora genus are common not only in forest nurseries and stands, but also in water courses. Species of Phytophthora spread with plants for plantings (and soil attached to them and with water courses as well, attacking the plants growing in riparian ecosystems. Several specialized organisms damaging only one tree species were identified like P. alni on alders or P. quercina on oaks. Some Phytophthora species can develop on several hosts like P. plurivora and P. cactorum on oaks, beeches, alders, ashes and horse chestnuts. Other oomycetes like P. gallica species was found for the first time in Poland in water used for plant watering in forest nursery. Species P. lacustris and P. gonapodyides were found in superficial water. Phytophthora species P. polonica was identified in the declining alder stands for the first time in the world, and P. taxon hungarica and P. megasperma were found in the rhizosphere of seriously damaged ash stands for the first time in Poland. The most often isolated species were P. plurivora (clade 2 with frequency 37% and P. lacustris with frequency 33% (clade 6. The best represented clade 6 revealed the occurrence of 6 species: P. gonapodyides, P. lacustris, P. megasperma, P. sp. raspberry, P. taxon hungarica and P. taxon oak soil.

  11. Summer survival of Phytophthora ramorum in California bay laurel leaves

    Science.gov (United States)

    Elizabeth J. Fichtner; David M. Rizzo; Shannon C. Lynch; Jennifer Davidson; Gerri Buckles; Jennifer Parker

    2008-01-01

    Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. Infected bay laurel leaves are more likely to abscise than uninfected leaves, resulting in an accumulation of inoculum at the forest floor. The pathogen survives the dry...

  12. First report of Phytophthora ramorum infecting grand fir in California

    Science.gov (United States)

    K.L. Riley; G.A. Chastagner

    2011-01-01

    Phytophthora ramorum was detected on grand fir in 2003 and 2005 in a Christmas tree plantation near Los Gatos, CA, in association with infected California bay laurel. Isolates derived from stem lesions were used to inoculate grand fir seedlings in two tests. Isolations from lesions on inoculated plants were positive for P. ramorum...

  13. First report of Phytophthora ramorum infecting mistletoe in California

    Science.gov (United States)

    K.L. Riley; G.A. Chastagner

    2011-01-01

    In 2005 and 2006, white fir and Douglas-fir growing in a Christmas tree plantation near Los Gatos, CA, under a black walnut tree infected with mistletoe tested positive for Phytophthora ramorum, the cause of Sudden Oak Death. Isolation from a symptomatic mistletoe inflorescence stalk was positive for P. ramorum. In 2007,...

  14. Phytophthora ramorum regulatory program: present, past, and future direction

    Science.gov (United States)

    Prakash Hebbar; Scott Pfister; Stacy Scott; Anthony Man-Son-Hing; Russ Bulluck

    2013-01-01

    Sudden oak death (SOD), caused by Phytophthora ramorum, is lethal to tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh), and threatens this species throughout its range in Oregon. The disease was first discovered in coastal southwest Oregon forests in July 2001. Since then an interagency team...

  15. Studies of tissue colonization in Rhododendron by Phytophthora ramorum

    Science.gov (United States)

    Marko Riedel; Stefan Wagner; Monika Götz; Lassaad Belbahri; Francois Lefort; Sabine Werres

    2008-01-01

    The knowledge on latency is of great importance to prevent the spread of Phytophthora ramorum with healthy looking plant material. To learn more about the tissue colonisation in Rhododendron, histological studies with epifluorescence microscopy have been started. Epifluorescence images showing P. ramorum structures in different...

  16. The maturation and germination of Phytophthora ramorum Chlamydospores

    Science.gov (United States)

    Aaron L. Smith; Everett M. Hansen

    2008-01-01

    Chlamydospores are a distinctive feature of Phytophthora ramorum. They are formed quickly in agar, and within colonized leaves. We followed their development and maturation in vitro and in vivo, and studied conditions affecting their germination. Cell walls of mature P. ramorum chlamydospores...

  17. Resistance to Phytophthora cinnamomi in the Genus Abies

    Science.gov (United States)

    John Frampton; Fikret Isik; Mike Benson; Jaroslav Kobliha; Jan Stjskal

    2012-01-01

    A major limiting factor for the culture of true firs as Christmas trees is their susceptibility to Oomycete species belonging to the genus Phytophthora. In North Carolina alone, the Fraser fir (Abies fraseri [Pursh] Poir.) Christmas tree industry loses 6 to 7 million dollars annually to root rot primarily caused by ...

  18. Histology of Phytophthora ramorum in Notholithocarpus densiflorus bark tissues

    Science.gov (United States)

    Molly Botts Giesbrecht; Everett M. Hansen; Peter Kitin

    2011-01-01

    Colonisation of Notholithocarpus densiflorus (Hook. and Arn.) Rehder tissues by Phytophthora ramorum Werres, De Cock & Man in't Veld is not well understood. The pathogen is able to colonise nearly all tissues of this host but it is unclear how a tree is ultimately killed. In this research,

  19. Antioxidant Enzyme Activities of some Brassica Species

    Directory of Open Access Journals (Sweden)

    Rodica SOARE

    2017-11-01

    Full Text Available This paper set out to comparatively study five species: white cabbage (Brassica oleracea L. var. capitata alba Alef., red cabbage (Brassica oleracea L. var. capitata f. rubra Alef., Kale (Brassica oleracea L. var. Acephala, cauliflower (Brassica oleracea var. botrytis and broccoli (Brassica oleracea var. cymosa in order to identify those with high enzymatic and antioxidant activities. The enzymatic activity of superoxide dismutase (SOD, catalase (CAT and soluble peroxidase (POX as well as the antioxidant activity against 2.2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS radical cation were determined. Total superoxide dismutase activity was measured spectrophotometrically based on inhibition in the photochemical reduction of nitroblue tetrazolium. Total soluble peroxidase was assayed by measuring the increase in A436 due to the guaiacol oxidation and the catalase activity was assayed through the colorimetric method. The capacity of extracts to scavenge the ABTS radical cation was assessed colorimetric using Trolox as a standard. The obtained results show that studied enzymatic activities and the antioxidant activity against ABTS vary depending on the analyzed species. So, among the studied Brassicaceae species, it emphasize red cabbage with the highest enzymatic activity (CAT 22.54 mM H2O2/min/g and POX 187.2 mM ΔA/1min/1g f.w. and kale with highest antioxidant activity, of 767 μmol TE/100g f.w. The results of this study recommendintroducing the studied varieties in diet due to the rich antioxidant properties.

  20. Two novel species representing a new clade and cluster of Phytophthora.

    Science.gov (United States)

    Yang, Xiao; Copes, Warren E; Hong, Chuanxue

    2014-01-01

    Phytophthora stricta sp. nov. and Phytophthora macilentosa sp. nov. are described based on morphological, physiological and molecular characters in this study. Phytophthora stricta represents a previously unknown clade in the rRNA internal transcribed spacer (ITS)-based phylogeny. Phytophthora macilentosa, along with nine other species, consistently forms a high temperature-tolerant cluster within ITS clade 9. These observations are supported by the sequence analysis of the mitochondrial cytochrome c oxidase 1 gene. Both species are heterothallic and all examined isolates are A1 mating type. Phytophthora stricta produces nonpapillate and slightly caducous sporangia. This species is named after its characteristic constrictions on sporangiophores. Phytophthora macilentosa produces nonpapillate and noncaducous sporangia, which are mostly elongated obpyriform with a high length to breadth ratio. Both species were recovered from irrigation water of an ornamental plant nursery in Mississippi, USA and P. stricta was also recovered from stream water in Virginia, USA. Copyright © 2013 The British Mycological Society. All rights reserved.

  1. Thermal inactivation of Phytophthora capsici oospores.

    Science.gov (United States)

    Etxeberria, Aitzol; Mendarte, Sorkunde; Larregla, Santiago

    2011-01-01

    Phytophthora capsici is a major fungal plant pathogen that causes root and crown rot of pepper crops and its oospores are the most resistant propagules. To evaluate the effect of different temperature regimes and exposure times on the survival of P. capsici oospores. Thermal inactivation treatments simulated field conditions, through the use of different constant and cycling temperature regimes, in moistened sterilized soil (15-53 °C) and sterilized water (45-53 °C). The plasmolysis method evaluated oospore viability. Relationships between oospores viability and exposure time were statistically determined by linear regression. Interpolation was used to calculate the estimated times required to kill a determined percentage of the population. The required time to reduce P. capsici oospores viability decreased with increasing temperatures. Times required to kill 100% of oospores were 199-22-6.6-4.7-1.0 hours at 40-45-47.5-50-53°C respectively in moistened soil and 31-1.0-0.2 hours at 45-50-53 °C in water. Oospores were scarcely affected at temperatures ≤ 35 °C. With 1,680 hours at 15-35 °C, oospores survival in soil ranged from 88 to 36%. The 4 hours-40 °C regime killed 100% of oospores after 28days, while the 5 hours-35°C regime after 70 days killed only 75%. Time required to achieve total oospores death was remarkably shortened in water when compared with moistened soil. The developed models can be used to predict survival values at any exposure time with constant temperatures ranging from 40 to 53 °C in moistened soil and from 45 to 53 °C in water. The weakening of P. capsici oospores under sublethal heating, is a useful observation that can be applied for pathogen control with solarization. Copyright © 2010 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  2. ELISA and ImmunoStrip® for detection of Phytophthora ramorum, P. kernoviae, and other Phytophthora species

    Science.gov (United States)

    Francisco J. Avila; Barbara Schoedel; Z. Gloria Abad; Michael D. Coffey; Cheryl Blomquist

    2009-01-01

    The goal of this work was to develop improved tools for the detection of Phytophthora ramorum and P. kernoviae for field and the laboratory use. ImmunoStrip® and ELISA were selected as the test formats for development. Presently, the diagnosis of sudden oak death (SOD) in the national survey of P. ramorum ...

  3. Phytophthora betacei, a new species within Phytophthora clade 1c causing late blight on Solanum betaceum in Colombia

    NARCIS (Netherlands)

    Mideros, M.F.; Turissini, D.A.; Guayazán, N.; Ibarra-Avila, H.; Danies, G.; Cárdenas, M.; Myers, K.; Tabima, J.; Goss, E.M.; Bernal, A.; Lagos, L.E.; Grajales, A.; Gonzalez, L.N.; Cooke, D.E.L.; Fry, W.E.; Grünwald, N.; Matute, D.R.; Restrepo, S.

    2018-01-01

    Over the past few years, symptoms akin to late blight disease have been reported on a variety of crop plants in South America. Despite the economic importance of these crops, the causal agents of the diseases belonging to the genus Phytophthora have not been completely characterized. In this study,

  4. NMR metabolomics of ripened and developing oilseed rape (Brassica napus) and turnip rape (Brassica rapa).

    Science.gov (United States)

    Kortesniemi, Maaria; Vuorinen, Anssi L; Sinkkonen, Jari; Yang, Baoru; Rajala, Ari; Kallio, Heikki

    2015-04-01

    The oilseeds of the commercially important oilseed rape (Brassica napus) and turnip rape (Brassica rapa) were investigated with (1)H NMR metabolomics. The compositions of ripened (cultivated in field trials) and developing seeds (cultivated in controlled conditions) were compared in multivariate models using principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Differences in the major lipids and the minor metabolites between the two species were found. A higher content of polyunsaturated fatty acids and sucrose were observed in turnip rape, while the overall oil content and sinapine levels were higher in oilseed rape. The genotype traits were negligible compared to the effect of the growing site and concomitant conditions on the oilseed metabolome. This study demonstrates the applicability of NMR-based analysis in determining the species, geographical origin, developmental stage, and quality of oilseed Brassicas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Biology and harmfulness of Brassica pod midge (Dasineura brassicae Winn. in winter oilseed rape

    Directory of Open Access Journals (Sweden)

    Draga Graora

    2015-04-01

    Full Text Available The Brassica pod midge (Dasineura brassicae Winn. is an important pest in oilseed rape (Brasica napus L.. It develops two generations per year and overwinters in the larval stage in cocoons in soil. Immigration of the first generation adults lasted from the beginning of April until the end of May. Larvae developed in pods from mid-April to mid-June, causing pod deformation and cracking, which resulted in premature falling out of seeds and yield reduction. Pod damage amounted to 11.6%. The emergence of the second generation adults was detected at the end of May and in the first ten days of June. D. brassicae was found to lay eggs in healthy pods and no correlation was found with the cabbage seed weevil, Ceutorhynchus assimilis Paykull.

  6. Phytophthora Root and Crown Rot on Apples in Bulgaria

    Directory of Open Access Journals (Sweden)

    Mariana Nakova

    2010-01-01

    Full Text Available Phytophthora is a genus of Oomycota responsible for some of the most serious diseases with great economic impact (Judelson and Blanco, 2005. While 54 species were found in the 20th century (Erwin and Ribeiro, 1996 another 51-54 new species have been identified(Brasier, 2008 since the year 2000. They are spread worldwide and have broad range of host plants – fruit trees, citrus, forest and park species. Phytophthora can cause serious damages in orchards and nurseries of apples, cherries, etc. In Bulgaria they have been found first on young apples and cherries (1998-1999 in Plovdiv region (Nakova, 2003. Surveys have been done for discovering disease symptoms in Plovdiv and Kjustendil regions. Isolates have been obtained from infected plant material (roots and stem bases applying baiting bioassay (green apples, variety Granny Smith and/or PARP 10 selective media. Phytophthora strains were identified based on standard morphology methods – types of colonies on PDA, CMA, V 8, type and size of sporangia, oogonia and antheridia, andoospores. Cardial temperatures for their growth were tested on CMA and PDA.For molecular studies, DNA was extracted from mycelium using the DNA extraction kit.DNA was amplified using universal primers ITS 6 and ITS 4. Amplification products concentrations were estimated by comparison with the standard DNA. Sequencing was done at the Scottish Crop Research Institute (SCRI, Dundee, Scotland. Phytophthora root and crown rot symptoms first appear in early spring. Infected trees show bud break delay, have small chlorotic leaves, and branches die all of a sudden. Later symptoms are found in August-September. Leaves of the infected trees show reddish discoloration and drop down. Both symptoms are connected with lesions (wet, necrotic in appearance at stem bases of the trees.Disease spread was 2-3% in most gardens, only in an apple orchard in Bjaga (Plovdiv region it was up to 8-10%. Morphologically, the isolates acquired from

  7. Inheritance of oilseed rape (Brassica napus) RAPD markers in a backcross progeny with Brassica campestris

    DEFF Research Database (Denmark)

    Mikkelsen, T.R.; Jensen, J.; Bagger Jørgensen, Rikke

    1996-01-01

    Different cultivars/transgenic lines of oilseed rape (Brassica napus) were crossed (as females) with different cultivars/populations of Brassica campestris. All cross combinations produced seed, with an average seed set per pollination of 9.8. Backcrossing of selected interspecific hybrids (as...... females) to B. campestris resulted in a much lower seed set, average 0.7 seed per pollination. In the single backcross progeny where a large enough population (92 plants) was obtained for analysis, 33 B. napus specific RAPD markers were investigated to determine the extent of transfer of oilseed rape...

  8. Occurrence of Phytophthora plurivora and other Phytophthora species in oak forests of southern Poland and their association with site conditions and the health status of trees.

    Science.gov (United States)

    Jankowiak, R; Stępniewska, H; Bilański, P; Kolařík, M

    2014-11-01

    Phytophthora plurivora and other Phytophthora species are known to be serious pathogens of forest trees. Little is known, however, about the presence of P. plurivora in Polish oak forests and their role in oak decline. The aims of this study were to identify P. plurivora in healthy and declining Quercus robur stands in southern Poland and to demonstrate the relationship between different site factors and the occurrence of P. plurivora. In addition, the virulence of P. plurivora and other Phytophthora species was evaluated through inoculations using 2-year-old oak seedlings. Rhizosphere soil was investigated from 39 oak stands representing different healthy tree statuses. The morphology and DNA sequences of the internal transcribed spacer regions (ITS) of the ribosomal DNA and the mitochondrial cox1 gene were used for identifications. P. plurivora, an oak fine root pathogen, was isolated from rhizosphere soil samples in 6 out of 39 stands. Additionally, Phytophthora cambivora, Phytophthora polonica and Phytophthora rosacearum-like were also obtained from several stands. The results showed a significant association between the presence of P. plurivora and the health status of oak trees. Similar relationships were also observed for all identified Phytophthora species. In addition, there was evidence for a connection between the presence of all identified Phytophthora species and some site conditions. Phytophthora spp. occurred more frequently in declining stands and in silt loam and sandy loam soils with pH ≥ 3.66. P. plurivora and P. cambivora were the only species capable of killing whole plants, producing extensive necrosis on seedling stems.

  9. Salt tolerance potential of brassica juncea Linn

    Energy Technology Data Exchange (ETDEWEB)

    Ibrar, M; Jabeen, M; Tabassum, J [University of Peshawar (Pakistan). Dept. of Botany; Hussain, F; Ilahi, I [University of Peshawar (Pakistan). Dept. of Pharmacy

    2003-07-01

    The present study showed that percent germination, radicle and plumule lengths of Brassica juncea were adversely affected by increasing the level of salinity. As compared to 95 per cent germination of the control, there were 92.50. 90.00. 90.00, 85.00, 87.50 and 80.00 per cent germinations respectively at 2.5, 5.0, 7.5. 10.0. 12.5 and 15.0 dSm/sup -1/ NaCI salinity levels. Similarly. all the parameters tested in the pot experiments showed gradual decline with the corresponding increasing levels of NaCl salinity. At lower levels of salinity (2.5 and 5.0 dSm/sup -l/), Brassica juncea had reasonably good growth and productivity. It showed greatly reduced growth and at 7.5 and 10.0 dSm/sup -1/ while at 12.5 and 15.0 10.0 dSm/sup -1/ salinity levels it was severely production affected. It is concluded from the present work that Brassica juncea can be grown fairly on mild saline soils for a food, fodder and seed production. (author)

  10. Salt tolerance potential of brassica juncea Linn

    International Nuclear Information System (INIS)

    Ibrar, M.; Jabeen, M.; Tabassum, J.; Hussain, F.; Ilahi, I.

    2003-01-01

    The present study showed that percent germination, radicle and plumule lengths of Brassica juncea were adversely affected by increasing the level of salinity. As compared to 95 per cent germination of the control, there were 92.50. 90.00. 90.00, 85.00, 87.50 and 80.00 per cent germinations respectively at 2.5, 5.0, 7.5. 10.0. 12.5 and 15.0 dSm/sup -1/ NaCI salinity levels. Similarly. all the parameters tested in the pot experiments showed gradual decline with the corresponding increasing levels of NaCl salinity. At lower levels of salinity (2.5 and 5.0 dSm/sup -l/), Brassica juncea had reasonably good growth and productivity. It showed greatly reduced growth and at 7.5 and 10.0 dSm/sup -1/ while at 12.5 and 15.0 10.0 dSm/sup -1/ salinity levels it was severely production affected. It is concluded from the present work that Brassica juncea can be grown fairly on mild saline soils for a food, fodder and seed production. (author)

  11. A review of mechanisms underlying anticarcinogenicity by brassica vegetables

    NARCIS (Netherlands)

    Verhoeven, D.T.H.; Verhagen, H.; Goldbohm, R.A.; Brandt, P.A. van den; Poppel, G. van

    1997-01-01

    The mechanisms by which brassica vegetables might decrease the risk of cancer are reviewed in this paper. Brassicas, including all types of cabbages, broccoli, cauliflower and Brussels sprouts, may be protective against cancer due to their relatively high glucosinolate content. Glucosinolates are

  12. Identification and evolutionary dynamics of cacta DNA transposons in brassica

    International Nuclear Information System (INIS)

    Nouroz, F.; Noreen, S.; Harrison, J.S.H.

    2017-01-01

    Transposable elements are the major drivers of genome evolution and plasticity. Due to their transposition mode, they are classified into two major classes as Retrotransposons and DNA transposons. The En/Spm or CACTA elements are diverse group of DNA transposons proliferating in plant genomes. Various bioinformatics and molecular approaches were used for identification and distribution of CACTA transposons in Brassica genome. A combination of dot plot analysis and BLASTN searches yielded 35 autonomous and 7 non-autonomous CACTA elements in Brassica. The elements ranged in sizes from 1.2 kb non-autonomous elements to 11kb autonomous elements, terminated by 3 bp Target Site Duplication (TSD) and ~15 bp conserved Terminal Inverted Repeat (TIR) motifs (5'-CACTACAAGAAAACA-3'), with heterogeneous internal regions. The transposase (TNP) was identified from autonomous CACTA elements, while other protein domains from Brassica and other plants CACTA revealed similar organizations with minor differences. Both transposases (TNPD, TNPA) are present in most CACTA, while a few CACTA harboured an additional ATHILA ORF1-like domain. The PCR analysis amplified the CACTA transposases from 40 Brassica accessions (A, B, and C-genome) suggesting their distribution among various Brassica crops. A detailed characterization and evolutionary analysis of the identified CACTA elements allowed some to be placed in genome-specific groups, while most of them (Brassica-Arabidopsis elements) have followed the same evolutionary line. The distribution of CACTA in Brassica concluded that 3 bp TSDs generating CACTA transposons contributed significantly to genome size and evolution of Brassica genome. (author)

  13. Epidemiological studies on Brassica vegetables and cancer risk

    NARCIS (Netherlands)

    Verhoeven, D.T.H.; Goldbohm, R.A.; Poppel, G. van; Verhagen, H.; Brandt, P.A. van den

    1996-01-01

    This paper gives an overview of the epidemiological data concerning the cancer-preventive effect of brassica vegetables, including cabbage, kale, broccoli, Brussels sprouts, and cauliflower. The protective effect of brassicas against cancer may be due to their relatively high content of

  14. Brassica oleracea: the dog of the plant world

    Science.gov (United States)

    The horticultural crop Brassica oleracea L. plays an important role in global food systems. Brassica oleracea is unique in that it has been domesticated into several morphotypes (cultivars), including broccoli, Brussels sprout, cabbage, cauliflower, kale, kohlrabi, and several lesser well known morp...

  15. Brassica oleracea; The dog of the plant world

    Science.gov (United States)

    The horticultural crop Brassica oleracea L. plays an important role in global food systems. Brassica oleracea is unique in that it has been domesticated into several morphotypes (cultivars), including broccoli, Brussels sprout, cabbage, cauliflower, kale, kohlrabi, and several lesser well known morp...

  16. Isolation of an ascorbate peroxidase in Brassica napus and analysis ...

    African Journals Online (AJOL)

    USER

    2010-04-05

    Apr 5, 2010 ... domain; APX, ascorbate peroxidase; Bn-APX, Brassica napus ascorbate ... Brassica napus, which is widely grown as the oilseed crop of rape or canola, .... grew on the SD-Leu-Trp-His-Ade medium and were verified by PCR.

  17. The oomycete broad-host-range pathogen Phytophthora capsici.

    Science.gov (United States)

    Lamour, Kurt H; Stam, Remco; Jupe, Julietta; Huitema, Edgar

    2012-05-01

    Phytophthora capsici is a highly dynamic and destructive pathogen of vegetables. It attacks all cucurbits, pepper, tomato and eggplant, and, more recently, snap and lima beans. The disease incidence and severity have increased significantly in recent decades and the molecular resources to study this pathogen are growing and now include a reference genome. At the population level, the epidemiology varies according to the geographical location, with populations in South America dominated by clonal reproduction, and populations in the USA and South Africa composed of many unique genotypes in which sexual reproduction is common. Just as the impact of crop loss as a result of P. capsici has increased in recent decades, there has been a similar increase in the development of new tools and resources to study this devastating pathogen. Phytophthora capsici presents an attractive model for understanding broad-host-range oomycetes, the impact of sexual recombination in field populations and the basic mechanisms of Phytophthora virulence. Kingdom Chromista; Phylum Oomycota; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; Genus Phytophthora; Species capsici. Symptoms vary considerably according to the host, plant part infected and environmental conditions. For example, in dry areas (e.g. southwestern USA and southern France), infection on tomato and bell or chilli pepper is generally on the roots and crown, and the infected plants have a distinctive black/brown lesion visible at the soil line (Fig. 1). In areas in which rainfall is more common (e.g. eastern USA), all parts of the plant are infected, including the roots, crown, foliage and fruit (Fig. 1). Root infections cause damping off in seedlings, whereas, in older plants, it is common to see stunted growth, wilting and, eventually, death. For tomatoes, it is common to see significant adventitious root growth just above an infected tap root, and the stunted plants, although severely compromised, may not die

  18. Interactions between biosurfactant-producing Pseudomonas and Phytophthora species

    OpenAIRE

    Tran, H.

    2007-01-01

    Fluorescent Pseudomonas bacteria produce a wide variety of antimicrobial metabolites, including soap-like compounds referred to as biosurfactants. The results of this thesis showed that biosurfactant-producing Pseudomonas bacteria are effective in controlling Phytophthora foot rot disease of black pepper in Vietnam and promote root and shoot development of the ‘King of Spices’. Biosurfactant-producing P. fluorescens strain SS101 was also effective in controlling tomato late blight caused by P...

  19. Infectivity and sporulation potential of Phytophthora kernoviae to select North American native plants

    Science.gov (United States)

    E. J. Fichtner; D. M. Rizzo; S. A. Kirk; J. F. Webber

    2011-01-01

    Phytophthora kernoviae exhibits comparable epidemiology to Phytophthora ramorum in invaded UK woodlands. Because both pathogens have an overlapping geographic range in the UK and often concurrently invade the same site, it is speculated that P. kernoviae may also invade North American (NA) forests...

  20. Efficacy of commercial algaecides to manage species of Phytophthora in suburban waterways

    Science.gov (United States)

    G. Curtis Colburn; Steven N. Jeffers

    2010-01-01

    Many commercial algaecides contain copper compounds as active ingredients. Phytophthora spp. and other oomycetes are known to be sensitive to copper-based fungicides. Therefore, algaecides registered to manage algae in natural waterways and irrigation waters also might be effective for mitigating or even eradicating Phytophthora ...

  1. Fungicides reduce Rhododendron root rot and mortality caused by Phytophthora cinnamomi, but not by P. plurivora

    Science.gov (United States)

    Rhododendron root rot, caused by several Phytophthora species, can cause devastating losses in nursery-grown plants. Most research on chemical control of root rot has focused on Phytophthora cinnamomi. However, it is unknown whether treatments recommended for P. cinnamomi are also effective for othe...

  2. Sporulation of Phytophthora ramorum and P. kernoviae on asymptomatic foliage and fruit

    Science.gov (United States)

    S. Denman; E. Moralejo; S.A. Kirk; E. Orton; A. Whybrow

    2008-01-01

    Phytophthora ramorum and P. kernoviae are newly discovered invasive Phytophthoras causing leaf necrosis, shoot tip dieback (mostly on ornamental and forest understorey host species) and bleeding cankers on tree trunks of a wide range of plant species. Both pathogens are now present in south-west England....

  3. Resistance to Phytophthora cinnamomi among seedlings from backcross families of hybrid american chestnut

    Science.gov (United States)

    Steven N. Jeffers; Inga M. Meadows; Joseph B. James; Paul H. Sisco

    2012-01-01

    American chestnut (Castanea dentata (Marsh.) Borkh.) once was a primary hardwood species in forests of the eastern United States. Sometime during the late 18th century, it is speculated that Phytophthora cinnamomi, which causes Phytophthora root rot (PRR) on many woody plant species, was introduced to the southeast region of...

  4. The interplay between a Phytophthora RXLR effector and an Arabidopsis lectin receptor kinase

    NARCIS (Netherlands)

    Bouwmeester, K.

    2010-01-01

    Phytophthora infestans – the causal agent of potato late blight – secretes a plethora of effector proteins to facilitate plant infection. The central subject of this thesis is ipiO, one of the first cloned Phytophthora genes with a putative function in pathogenicity as was anticipated based on its

  5. Variation in density and diversity of species of Phytophthora in two forest stream networks

    Science.gov (United States)

    Jaesoon Hwang; Steven N. Jeffers; Steven W. Oak

    2010-01-01

    Monitoring occurrence and distribution of Phytophthora species, including Phytophthora ramorum, in forest ecosystems can be achieved in several ways including sampling symptomatic plants, infested soils, and infested streams. Collecting plant and soil samples can be laborious and time consuming due to the distance surveyors...

  6. Introduction of filtration systems in container nurseries for nonchemical elimination of Phytophthora spp. from irrigation water

    Science.gov (United States)

    Thorsten Ufer; Heinrich Beltz; Thomas Brand; Katrin Kaminski; Ralf Lüttmann; Martin Posner; Stefan Wagner; Sabine Werres; Hans-Peter Wessels

    2006-01-01

    In a 3-year project the elimination of Phytophthora spp. from the recirculation water with different kinds of filtration systems will be tested under commercial conditions in container nurseries. First results indicate that the filtration systems eliminate Phytophthora spp. from the water.

  7. Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across southeastern United States

    Science.gov (United States)

    Southeastern states produce about 50% of the watermelons in the United States (U.S.) where conditions are optimal for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses to growers before and after harvest. ...

  8. Microbial- and isothiocyanate-mediated control of Phytophthora and Pythium species

    Science.gov (United States)

    M.F. Cohen; E. Yamamoto; E. Condeso; B.L. Anacker; N. Rank; M. Mazzola

    2008-01-01

    Plant pathogens of the oomycete lineage share common susceptibilities to many biotic and abiotic stresses. We are investigating the potential of antagonistic bacteria, isothiocyanates, and mycophagous amoebae to control diseases caused by Phytophthora spp., including the etiologic agent of sudden oak death, Phytophthora ramorum (...

  9. Phylogenetic Analysis of Phytophthora Species Based on Mitochondrial and Nuclear DNA Sequences

    NARCIS (Netherlands)

    Kroon, L.P.N.M.; Bakker, F.T.; Bosch, van den G.B.M.; Bonants, P.J.M.; Flier, W.G.

    2004-01-01

    A molecular phylogenetic analysis of the genus Phytophthora was performed, 113 isolates from 48 Phytophthora species were included in this analysis. Phylogenetic analyses were performed on regions of mitochondrial (cytochrome c oxidase subunit 1; NADH dehydrogenase subunit 1) and nuclear gene

  10. Molecular tools to unravel the role of genes from Phytophthora infestans

    NARCIS (Netherlands)

    West, van P.

    2000-01-01

    The oomycete plant pathogen Phytophthora infestans is the causal agent of potato late blight. P. infestans is undoubtedly the best known and most studied Phytophthora species today. This is mainly because it is such a

  11. Phytophthora database 2.0: update and future direction.

    Science.gov (United States)

    Park, Bongsoo; Martin, Frank; Geiser, David M; Kim, Hye-Seon; Mansfield, Michele A; Nikolaeva, Ekaterina; Park, Sook-Young; Coffey, Michael D; Russo, Joseph; Kim, Seong H; Balci, Yilmaz; Abad, Gloria; Burgess, Treena; Grünwald, Niklaus J; Cheong, Kyeongchae; Choi, Jaeyoung; Lee, Yong-Hwan; Kang, Seogchan

    2013-12-01

    The online community resource Phytophthora database (PD) was developed to support accurate and rapid identification of Phytophthora and to help characterize and catalog the diversity and evolutionary relationships within the genus. Since its release in 2008, the sequence database has grown to cover 1 to 12 loci for ≈2,600 isolates (representing 138 described and provisional species). Sequences of multiple mitochondrial loci were added to complement nuclear loci-based phylogenetic analyses and diagnostic tool development. Key characteristics of most newly described and provisional species have been summarized. Other additions to improve the PD functionality include: (i) geographic information system tools that enable users to visualize the geographic origins of chosen isolates on a global-scale map, (ii) a tool for comparing genetic similarity between isolates via microsatellite markers to support population genetic studies, (iii) a comprehensive review of molecular diagnostics tools and relevant references, (iv) sequence alignments used to develop polymerase chain reaction-based diagnostics tools to support their utilization and new diagnostic tool development, and (v) an online community forum for sharing and preserving experience and knowledge accumulated in the global Phytophthora community. Here we present how these improvements can support users and discuss the PD's future direction.

  12. Effect of CO2 enhancement on beech (Fagus sylvatica L. seedling root rot due to Phytophthora plurivora and Phytophthora cactorum

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2014-09-01

    Full Text Available Global climate change is associated with higher concentrations of atmospheric carbon dioxide (CO2. The ongoing changes are likely to have significant, direct or indirect effects on plant diseases caused by many biotic agents such as phytopathogenic fungi. This study results showed that increased CO2 concentration did not stimulate the growth of 1-year-old beech Fagus sylvatica L seedlings but it activated pathogenic Phytophthora species (P. plurivora and P. cactorum which caused significant reduction in the total number of fine roots as well as their length and area. The results of the greenhouse experiment indicated that pathogens once introduced into soil survived in pot soil, became periodically active (in sufficient water conditions and were able to damage beech fine roots. However, the trees mortality was not observed during the first year of experiment. DNA analyses performed on soil and beech tissue proved persistence of introduced Phytophthora isolates.

  13. Small homologous blocks in phytophthora genomes do not point to an ancient whole-genome duplication.

    Science.gov (United States)

    van Hooff, Jolien J E; Snel, Berend; Seidl, Michael F

    2014-05-01

    Genomes of the plant-pathogenic genus Phytophthora are characterized by small duplicated blocks consisting of two consecutive genes (2HOM blocks) and by an elevated abundance of similarly aged gene duplicates. Both properties, in particular the presence of 2HOM blocks, have been attributed to a whole-genome duplication (WGD) at the last common ancestor of Phytophthora. However, large intraspecies synteny-compelling evidence for a WGD-has not been detected. Here, we revisited the WGD hypothesis by deducing the age of 2HOM blocks. Two independent timing methods reveal that the majority of 2HOM blocks arose after divergence of the Phytophthora lineages. In addition, a large proportion of the 2HOM block copies colocalize on the same scaffold. Therefore, the presence of 2HOM blocks does not support a WGD at the last common ancestor of Phytophthora. Thus, genome evolution of Phytophthora is likely driven by alternative mechanisms, such as bursts of transposon activity.

  14. Diversity of Phytophthora Species from Declining Mediterranean Maquis Vegetation, including Two New Species, Phytophthora crassamura and P. ornamentata sp. nov.

    Science.gov (United States)

    Scanu, Bruno; Linaldeddu, Benedetto T.; Deidda, Antonio; Jung, Thomas

    2015-01-01

    The Mediterranean basin is recognized as a global biodiversity hotspot accounting for more than 25,000 plant species that represent almost 10% of the world’s vascular flora. In particular, the maquis vegetation on Mediterranean islands and archipelagos constitutes an important resource of the Mediterranean plant diversity due to its high rate of endemism. Since 2009, a severe and widespread dieback and mortality of Quercus ilex trees and several other plant species of the Mediterranean maquis has been observed in the National Park of La Maddalena archipelago (northeast Sardinia, Italy). Infected plants showed severe decline symptoms and a significant reduction of natural regeneration. First studies revealed the involvement of the highly invasive wide-host range pathogen Phytophthora cinnamomi and several fungal pathogens. Subsequent detailed research led to a better understanding of these epidemics showing that multiple Phytophthora spp. were involved, some of them unknown to science. In total, nine Phytophthora species were isolated from rhizosphere soil samples collected from around symptomatic trees and shrubs including Asparagus albus, Cistus sp., Juniperus phoenicea, J. oxycedrus, Pistacia lentiscus and Rhamnus alaternus. Based on morphological characters, growth-temperature relations and sequence analysis of the ITS and cox1 gene regions, the isolates were identified as Phytophthora asparagi, P. bilorbang, P. cinnamomi, P. cryptogea, P. gonapodyides, P. melonis, P. syringae and two new Clade 6 taxa which are here described as P. crassamura sp. nov. and P. ornamentata sp. nov. Pathogenicity tests supported their possible involvement in the severe decline that is currently threatening the Mediterranean maquis vegetation in the La Maddalena archipelago. PMID:26649428

  15. Subgenome parallel selection is associated with morphotype diversification and convergent crop domestication in Brassica rapa and Brassica oleracea.

    Science.gov (United States)

    Cheng, Feng; Sun, Rifei; Hou, Xilin; Zheng, Hongkun; Zhang, Fenglan; Zhang, Yangyong; Liu, Bo; Liang, Jianli; Zhuang, Mu; Liu, Yunxia; Liu, Dongyuan; Wang, Xiaobo; Li, Pingxia; Liu, Yumei; Lin, Ke; Bucher, Johan; Zhang, Ningwen; Wang, Yan; Wang, Hui; Deng, Jie; Liao, Yongcui; Wei, Keyun; Zhang, Xueming; Fu, Lixia; Hu, Yunyan; Liu, Jisheng; Cai, Chengcheng; Zhang, Shujiang; Zhang, Shifan; Li, Fei; Zhang, Hui; Zhang, Jifang; Guo, Ning; Liu, Zhiyuan; Liu, Jin; Sun, Chao; Ma, Yuan; Zhang, Haijiao; Cui, Yang; Freeling, Micheal R; Borm, Theo; Bonnema, Guusje; Wu, Jian; Wang, Xiaowu

    2016-10-01

    Brassica species, including crops such as cabbage, turnip and oilseed, display enormous phenotypic variation. Brassica genomes have all undergone a whole-genome triplication (WGT) event with unknown effects on phenotype diversification. We resequenced 199 Brassica rapa and 119 Brassica oleracea accessions representing various morphotypes and identified signals of selection at the mesohexaploid subgenome level. For cabbage morphotypes with their typical leaf-heading trait, we identified four subgenome loci that show signs of parallel selection among subgenomes within B. rapa, as well as four such loci within B. oleracea. Fifteen subgenome loci are under selection and are shared by these two species. We also detected strong subgenome parallel selection linked to the domestication of the tuberous morphotypes, turnip (B. rapa) and kohlrabi (B. oleracea). Overall, we demonstrated that the mesohexaploidization of the two Brassica genomes contributed to their diversification into heading and tuber-forming morphotypes through convergent subgenome parallel selection of paralogous genes.

  16. A Phylogenetic Analysis of Chloroplast Genomes Elucidates the Relationships of the Six Economically Important Brassica Species Comprising the Triangle of U

    NARCIS (Netherlands)

    Li, Peirong; Zhang, Shujiang; Li, Fei; Zhang, Shifan; Zhang, Hui; Wang, Xiaowu; Sun, Rifei; Bonnema, Guusje; Borm, Theo J.A.

    2017-01-01

    The Brassica genus comprises many economically important worldwide cultivated crops. The well-established model of the Brassica genus, U’s triangle, consists of three basic diploid plant species (Brassica rapa, Brassica oleracea, and Brassica nigra) and three amphidiploid species (Brassica napus,

  17. Oilseed brassica improvement through induced mutations

    International Nuclear Information System (INIS)

    Shah, S.A.; Ali, I.; Rehman, K.

    1992-07-01

    The improvement in processing and refining technologies of oil seed brassica have now made possible the use of rape seed mustard oil as cooking medium shortening, salad ingredients and in margarine in many countries. Different promising rape seed mutants were tested for yield and other agronomic traits in eight preliminary yields trails and results of these trails are presented in this report. Three varieties of rape seeds were subjected to 80, 100, 120 krads and two varieties of mustard were treated 60, 80, 100 krads dose of gamma rays. (A.B.)

  18. BRAD, the genetics and genomics database for Brassica plants

    Directory of Open Access Journals (Sweden)

    Li Pingxia

    2011-10-01

    Full Text Available Abstract Background Brassica species include both vegetable and oilseed crops, which are very important to the daily life of common human beings. Meanwhile, the Brassica species represent an excellent system for studying numerous aspects of plant biology, specifically for the analysis of genome evolution following polyploidy, so it is also very important for scientific research. Now, the genome of Brassica rapa has already been assembled, it is the time to do deep mining of the genome data. Description BRAD, the Brassica database, is a web-based resource focusing on genome scale genetic and genomic data for important Brassica crops. BRAD was built based on the first whole genome sequence and on further data analysis of the Brassica A genome species, Brassica rapa (Chiifu-401-42. It provides datasets, such as the complete genome sequence of B. rapa, which was de novo assembled from Illumina GA II short reads and from BAC clone sequences, predicted genes and associated annotations, non coding RNAs, transposable elements (TE, B. rapa genes' orthologous to those in A. thaliana, as well as genetic markers and linkage maps. BRAD offers useful searching and data mining tools, including search across annotation datasets, search for syntenic or non-syntenic orthologs, and to search the flanking regions of a certain target, as well as the tools of BLAST and Gbrowse. BRAD allows users to enter almost any kind of information, such as a B. rapa or A. thaliana gene ID, physical position or genetic marker. Conclusion BRAD, a new database which focuses on the genetics and genomics of the Brassica plants has been developed, it aims at helping scientists and breeders to fully and efficiently use the information of genome data of Brassica plants. BRAD will be continuously updated and can be accessed through http://brassicadb.org.

  19. Four different Phytophthora species that are able to infect Scots pine seedlings in laboratory conditions

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2016-09-01

    Full Text Available To investigate susceptibility of young Scots pine seedlings to four Phytophthora species: Phytophthora cactorum, Phytophthora cambivora, Phytophthora plurivora and Phytophthora pini; seven-day-old seedlings of Scots pine (15 seedlings per experiment were infected using agar plugs of the respective species. Control group also consisted of 15 seedlings and was inoculated with sterile agar plugs. Results unambiguously show that after 4.5 days, all seedlings show clear signs of infection and display severe symptoms of tissue damage and necrosis. Moreover, three and two seedlings in the P. cactorum and P. cambivora infected seedlings groups, respectively, collapsed. The length of largest necrosis measured 13.4±3.90 mm and was caused by P. cactorum. To rule out any putative contamination or infection by secondary pathogens, re-isolations of pathogens from infection sites were performed and were positive in 100% of plated pieces of infected seedlings. All re-isolations were, however, negative in the case of the control group. Detailed microscopic analyses of infected tissues of young seedlings confirmed the presence of numerous Phytophthora species inside and on the surface of infected seedlings. Therefore, our results suggest Phytophthora spp. and mainly P. cactorum and P. cambivora as aggressive pathogens of Scots pine seedlings and highlight a putative involvement of these species in the damping off of young Scots pine seedlings frequently observed in forest nurseries.

  20. Transcriptome analysis of Brassica juncea var. tumida Tsen responses to Plasmodiophora brassicae primed by the biocontrol strain Zhihengliuella aestuarii.

    Science.gov (United States)

    Luo, Yuanli; Dong, Daiwen; Su, Yu; Wang, Xuyi; Peng, Yumei; Peng, Jiang; Zhou, Changyong

    2018-05-01

    Mustard clubroot, caused by Plasmodiophora brassicae, is a serious disease that affects Brassica juncea var. tumida Tsen, a mustard plant that is the raw material for a traditional fermented food manufactured in Chongqing, China. In our laboratory, we screened the antagonistic bacteria Zhihengliuella aestuarii against P. brassicae. To better understand the biocontrol mechanism, three transcriptome analyses of B. juncea var. tumida Tsen were conducted using Illumina HiSeq 4000, one from B. juncea only inoculated with P. brassicae (P), one inoculated with P. brassica and the biocontrol agent Z. aestuarii at the same time (P + B), and the other was the control (H), in which P. brassicae was replaced by sterile water. A total of 19.94 Gb was generated by Illumina HiSeq sequencing. The sequence data were de novo assembled, and 107,617 unigenes were obtained. In total, 5629 differentially expressed genes between biocontrol-treated (P + B) and infected (P) samples were assigned to 126 KEGG pathways. Using multiple testing corrections, 20 pathways were significantly enriched with Qvalue ≤ 0.05. The resistance-related genes, involved in the production of pathogenesis-related proteins, pathogen-associated molecular pattern-triggered immunity, and effector-triggered immunity signaling pathways, calcium influx, salicylic acid pathway, reactive oxygen intermediates, and mitogen-activated protein kinase cascades, and cell wall modification, were obtained. The various defense responses induced by the biocontrol strain combatted the P. brassicae infection. The genes and pathways involved in plant resistance were induced by a biocontrol strain. The transcriptome data explained the molecular mechanism of the potential biocontrol strain against P. brassicae. The data will also serve as an important public information platform to study B. juncea var. tumida Tsen and will be useful for breeding mustard plants resistant to P. brassicae.

  1. Phytophthora Species in Rivers and Streams of the Southwestern United States.

    Science.gov (United States)

    Stamler, Rio A; Sanogo, Soumalia; Goldberg, Natalie P; Randall, Jennifer J

    2016-08-01

    Phytophthora species were isolated from rivers and streams in the southwestern United States by leaf baiting and identified by sequence analysis of internal transcribed spacer (ITS) ribosomal DNA (rDNA). The major waterways examined included the Rio Grande River, Gila River, Colorado River, and San Juan River. The most prevalent species identified in rivers and streams were Phytophthora lacustris and P. riparia, both members of Phytophthora ITS clade 6. P. gonapodyides, P. cinnamomi, and an uncharacterized Phytophthora species in clade 9 were also recovered. In addition, six isolates recovered from the Rio Grande River were shown to be hybrids of P. lacustris × P. riparia Pathogenicity assays using P. riparia and P. lacustris failed to produce any disease symptoms on commonly grown crops in the southwestern United States. Inoculation of Capsicum annuum with P. riparia was shown to inhibit disease symptom development when subsequently challenged with P. capsici, a pathogenic Phytophthora species. Many Phytophthora species are significant plant pathogens causing disease on a large variety of crops worldwide. Closer examinations of streams, rivers, and forest soils have also identified numerous Phytophthora species that do not appear to be phytopathogens and likely act as early saprophytes in aquatic and saturated environments. To date, the Phytophthora species composition in rivers and streams of the southwestern United States has not been evaluated. This article details a study to determine the identity and prevalence of Phytophthora species in rivers and streams located in New Mexico, Arizona, Colorado, Utah, and Texas. Isolated species were evaluated for pathogenicity on crop plants and for their potential to act as biological control agents. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  2. Host Adaptation and Speciation through Hybridization and Polyploidy in Phytophthora

    Science.gov (United States)

    Bertier, Lien; Leus, Leen; D’hondt, Liesbet; de Cock, Arthur W. A. M.; Höfte, Monica

    2013-01-01

    It is becoming increasingly evident that interspecific hybridization is a common event in phytophthora evolution. Yet, the fundamental processes underlying interspecific hybridization and the consequences for its ecological fitness and distribution are not well understood. We studied hybridization events in phytophthora clade 8b. This is a cold-tolerant group of plant pathogenic oomycetes in which six host-specific species have been described that mostly attack winter-grown vegetables. Hybrid characterization was done by sequencing and cloning of two nuclear (ITS and Ypt1) and two mitochondrial loci (Cox1 and Nadh1) combined with DNA content estimation using flow cytometry. Three different mtDNA haplotypes were recovered among the presumed hybrid isolates, dividing the hybrids into three types, with different parental species involved. In the nuclear genes, additivity, i.e. the presence of two alleles coming from different parents, was detected. Hybrid isolates showed large variations in DNA content, which was positively correlated with the additivity in nuclear loci, indicating allopolyploid hybridization followed by a process of diploidization. Moreover, indications of homeologous recombination were found in the hybrids by cloning ITS products. The hybrid isolates have been isolated from a range of hosts that have not been reported previously for clade 8b species, indicating that they have novel pathogenic potential. Next to this, DNA content measurements of the non-hybrid clade 8b species suggest that polyploidy is a common feature of this clade. We hypothesize that interspecific hybridization and polyploidy are two linked phenomena in phytophthora, and that these processes might play an important and ongoing role in the evolution of this genus. PMID:24386473

  3. Antifungal Effect of Plant Essential Oils on Controlling Phytophthora Species

    Directory of Open Access Journals (Sweden)

    Jahanshir Amini

    2016-02-01

    Full Text Available In this study, antifungal activity of essential oils of Cymbopogon citratus and Ocimum basilicum and two fungicides Mancozeb and Metalaxyl-Mancozeb in six different concentrations were investigated for controlling three species of Phytophthora, including P. capsici, P. drechsleri and P. melonis on pepper, cucumber and melon under in vitro and greenhouse conditions, respectively. Under the in vitro condition, the median effective concen- tration (EC₅₀ values (ppm of plant essential oils and fungicides were measured. In greenhouse, soil infested with Phytophthora species was treated by adding 50 ml of essential oils and fungicides (100 ppm. Disease severity was determined after 28 days. Among two tested plant essential oils, C. citratus had the lowest EC₅₀ values for inhibition of the mycelial growth of P. capsici (31.473, P. melonis (33.097 and P. drechsleri (69.112, respectively. The mean EC₅₀ values for Metalaxyl-Mancozeb on these pathogens were 20.87, 20.06 and 17.70, respectively. Chemical analysis of plant essential oils by GC-MS showed that, among 42 compounds identified from C. citratus, two compounds β-geranial (α-citral (39.16% and z-citral (30.95% were the most abundant. Under the greenhouse condition, Metalaxyl-Mancozeb caused the greatest reduction in disease severity, 84.2%, 86.8% and 92.1% on melon, cucumber, and pepper, respectively. The C. citratus essential oil reduced disease severity from 47.4% to 60.5% compared to the untreated control (p≤0.05. Essential oils of O. basilicum had the lowest effects on the pathogens under in vitro and greenhouse conditions. These results show that essential oils may contribute to the development of new antifungal agents to protect the crops from Phytophthora diseases.

  4. Methods for Detection of Phytophthora fragariae var. rubi on Raspberry

    Directory of Open Access Journals (Sweden)

    Mirjana Koprivica

    2009-01-01

    Full Text Available Phytophthora fragariae var. rubi (Wilcox & Duncan, a causal agent of raspberry root rot, is a serious soil-borne pathogen listed by EPPO as an A2 quarantine pest. Root samples were collected from badly diseased raspberry plants showing a variety of characteristic and often dramatic symptoms during surveys carried out in western Serbia in 2002. Identification of the causal agent was performed in collaboration work with the Scottish Crop Research Institute (S.C.R.I., Dundee, UK. Necrotic roots were plated on selective French bean agar (incorporating ampicilin, ryfamicin, bavistin and hymexasol. Detection of isolates was based on cultural and morphological features compared with referent cultures. DNA was extracted directly from the sampled roots using extraction buffer (200 mM Tris- HCl pH 8.5, 250 mM NaCl, 25 mM EDTA, 0.5% SDS, purified by multi spin separation columns [Thistle Scientific (Axygen] or in 24:1 mixture of chlorophorm- iso-amyl alcohol and amplified by nested PCR (ITS4 and DC6 for first round, DC1and DC5 for second round. Diluted DNA extracts were also amplified by conventional PCR with modified ”universal” Phytophthora primers (ITS 6, ITS 7 and ITS 8, Cooke et al., 2000 and digested with Msp1. Digestion patterns of the universal primers PCR product from infected roots matched those of Scottish strains. P. fragariae var. rubi occured on 8 out of 14 sites. Our results indicate that nested PCR (ITS4 and DC6 for first round, DC1 and DC5 for second round or digestion of the ”universal” Phytophthora primers PCR product for detection of P. fragariae var. rubi are more sensitive and less time-consuming and therefore recommended for use.

  5. PsMPK7, a stress-associated mitogen-activated protein kinase (MAPK) in Phytophthora sojae, is required for stress tolerance, reactive oxygenated species detoxification, cyst germination, sexual reproduction and infection of soybean.

    Science.gov (United States)

    Gao, Jian; Cao, Mingna; Ye, Wenwu; Li, Haiyang; Kong, Liang; Zheng, Xiaobo; Wang, Yuanchao

    2015-01-01

    The sensing of stress signals and their transduction into appropriate responses are crucial for the adaptation, survival and infection of phytopathogenic fungi and oomycetes. Amongst evolutionarily conserved pathways, mitogen-activated protein kinase (MAPK) cascades function as key signal transducers that use phosphorylation to convey information. In this study, we identified a gene, designated PsMPK7, one of 14 predicted genes encoding MAPKs in Phytophthora sojae. PsMPK7 was highly transcribed in each tested stage, but was up-regulated in the zoospore, cyst and cyst germination stages. Silencing of PsMPK7 affected the growth of germinated cysts, oospore production and the pathogenicity of soybean. PsMPK7 transcription was induced by stresses from sorbitol, NaCl and hydrogen peroxide. Transformants in which PsMPK7 expression was silenced (PsMPK7-silenced) were significantly more sensitive to osmotic and oxidative stress. Aniline blue and diaminobenzidine staining revealed that the silenced lines did not suppress the host reactive oxygen species (ROS) burst, indicating that either the inoculated plants activated stronger defence responses to the transformants and/or the PsMPK7-silenced transformants failed to overcome plant defences. In addition, extracellular secretion of laccase decreased in the silenced lines. Overall, our results indicate that the PsMPK7 gene encodes a stress-associated MAPK in P. sojae that is important not only for responses to various stresses, but also for ROS detoxification, cyst germination, sexual oospore production and infection of soybean. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  6. Origin of new Brassica types from a single intergeneric hybrid ...

    Indian Academy of Sciences (India)

    Origin of new Brassica types from a single intergeneric hybrid between B. rapa and Orychophragmus ... The morphological and genetic divergence of these novel types derived from a single hybrid is probably due ... Journal of Genetics | News.

  7. Yield performance of brassica varieties under rainfed condition

    International Nuclear Information System (INIS)

    Hassan, M.Z.U.; Wahla, A.J.; Waqar, M.Q.

    2014-01-01

    A field study was conducted to evaluate crop growth and seed yield performance of Brassica varieties under Rainfed conditions. The varieties, included in the study, were BSA, Zafar-2000, Pakola, Con.1, Con.2, Abaseen, Rainbow, SPS-5, Bard-1, and KJ-119. KJ-119 (2500.0 KG/HA) among Brassica juncea L. varieties and Abaseen (2425.9 kg/ha) among Brassica napusL. Varieties produced with maximum seed yield as compared to rest of varieties. Significantly, minimum seed yield was observed in check variety BSA. The significant difference in seed yield of Brassica varieties, Abaseen and KJ 119, was attributed to improve yield components over other varieties. Maximum pods per plant and seeds per pod led these varieties to attain maximum yield. Inspite of weather variations existence during years 2007-09,the same varieties produced with maximum seed yield. (author)

  8. Identification of novel QTLs for isolate-specific partial resistance to Plasmodiophora brassicae in Brassica rapa.

    Directory of Open Access Journals (Sweden)

    Jingjing Chen

    Full Text Available Plasmodiophora brassicae, the causal agent of clubroot disease of the Brassica crops, is widespread in the world. Quantitative trait loci (QTLs for partial resistance to 4 different isolates of P. brassicae (Pb2, Pb4, Pb7, and Pb10 were investigated using a BC1F1 population from a cross between two subspecies of Brassica rapa, i.e. Chinese cabbage inbred line C59-1 as a susceptible recurrent parent and turnip inbred line ECD04 as a resistant donor parent. The BC1F2 families were assessed for resistance under controlled conditions. A linkage map constructed with simple sequence repeats (SSR, unigene-derived microsatellite (UGMS markers, and specific markers linked to published clubroot resistance (CR genes of B. rapa was used to perform QTL mapping. A total of 6 QTLs residing in 5 CR QTL regions of the B. rapa chromosomes A01, A03, and A08 were identified to account for 12.2 to 35.2% of the phenotypic variance. Two QTL regions were found to be novel except for 3 QTLs in the respective regions of previously identified Crr1, Crr2, and Crr3. QTL mapping results indicated that 1 QTL region was common for partial resistance to the 2 isolates of Pb2 and Pb7, whereas the others were specific for each isolate. Additionally, synteny analysis between B. rapa and Arabidopsis thaliana revealed that all CR QTL regions were aligned to a single conserved crucifer blocks (U, F, and R on 3 Arabidopsis chromosomes where 2 CR QTLs were detected in A. thaliana. These results suggest that some common ancestral genomic regions were involved in the evolution of CR genes in B. rapa.

  9. Metabolic profiling and biological capacity of Pieris brassicae fed with kale (Brassica oleracea L. var. acephala).

    Science.gov (United States)

    Ferreres, Federico; Fernandes, Fátima; Oliveira, Jorge M A; Valentão, Patrícia; Pereira, José A; Andrade, Paula B

    2009-06-01

    Phenolic and organic acid profiles of aqueous extracts from Pieris brassicae material and the host kale (Brassica oleracea L. var. acephala) leaves were determined by HPLC/UV-DAD/MS(n)-ESI and HPLC-UV, respectively. The identified phenolics included acylated and nonacylated flavonoid glycosides, hydroxycinnamic acyl gentiobiosides, and sulphate phenolics. Kale exhibited the highest content (11g/kg lyophilized extract), while no phenolics were identified in the butterflies or exuviae. Nine different organic acids were characterized in the materials, with kale showing the highest amount (112g/kg lyophilized extract). With the exception of the exuviae extract, the rest were screened for bioactivity. Using spectrophotometric microassays, all exhibited antiradical capacity against DPPH and NO in a concentration-dependent way, whereas only kale and excrement extracts were active against superoxide. All displayed activity on intestinal smooth muscle, albeit with distinct relaxation-contraction profiles. Larvae and butterfly extracts were more efficacious for intestinal relaxation than was kale extract, whereas excrement extract evoked only contractions, thus evidencing their different compositions. Collectively, these results show that P. brassicae sequesters and metabolizes kale's phenolic compounds. Moreover, the extract's bioactivities suggest that they may constitute an interesting source of bioactive compounds whose complex chemical structures preclude either synthesis or isolation.

  10. Comparative Transcriptome Analysis between Broccoli (Brassica oleracea var. italica) and Wild Cabbage (Brassica macrocarpa Guss.) in Response to Plasmodiophora brassicae during Different Infection Stages.

    Science.gov (United States)

    Zhang, Xiaoli; Liu, Yumei; Fang, Zhiyuan; Li, Zhansheng; Yang, Limei; Zhuang, Mu; Zhang, Yangyong; Lv, Honghao

    2016-01-01

    Clubroot, one of the most devastating diseases to the Brassicaceae family, is caused by the obligate biotrophic pathogen Plasmodiophora brassicae . However, studies of the molecular basis of disease resistance are still poor especially in quantitative resistance. In the present paper, two previously identified genotypes, a clubroot-resistant genotype (wild cabbage, B2013) and a clubroot-susceptible genotype (broccoli, 90196) were inoculated by P. brassicae for 0 (T0), 7 (T7), and 14 (T14) day after inoculation (DAI). Gene expression pattern analysis suggested that response changes in transcript level of two genotypes under P. brassicae infection were mainly activated at the primary stage (T7). Based on the results of DEGs functional enrichments from two infection stages, genes associated with cell wall biosynthesis, glucosinolate biosynthesis, and plant hormone signal transduction showed down-regulated at T14 compared to T7, indicating that defense responses to P. brassicae were induced earlier, and related pathways were repressed at T14. In addition, the genes related to NBS-LRR proteins, SA signal transduction, cell wall and phytoalexins biosynthesis, chitinase, Ca 2+ signals and RBOH proteins were mainly up-regulated in B2013 by comparing those of 90196, indicating the pathways of response defense to clubroot were activated in the resistant genotype. This is the first report about comparative transcriptome analysis for broccoli and its wild relative during the different stages of P. brassicae infection and the results should be useful for molecular assisted screening and breeding of clubroot-resistant genotypes.

  11. The compact genome of the plant pathogen Plasmodiophora brassicae is adapted to intracellular interactions with host Brassica spp.

    Science.gov (United States)

    Rolfe, Stephen A; Strelkov, Stephen E; Links, Matthew G; Clarke, Wayne E; Robinson, Stephen J; Djavaheri, Mohammad; Malinowski, Robert; Haddadi, Parham; Kagale, Sateesh; Parkin, Isobel A P; Taheri, Ali; Borhan, M Hossein

    2016-03-31

    The protist Plasmodiophora brassicae is a soil-borne pathogen of cruciferous species and the causal agent of clubroot disease of Brassicas including agriculturally important crops such as canola/rapeseed (Brassica napus). P. brassicae has remained an enigmatic plant pathogen and is a rare example of an obligate biotroph that resides entirely inside the host plant cell. The pathogen is the cause of severe yield losses and can render infested fields unsuitable for Brassica crop growth due to the persistence of resting spores in the soil for up to 20 years. To provide insight into the biology of the pathogen and its interaction with its primary host B. napus, we produced a draft genome of P. brassicae pathotypes 3 and 6 (Pb3 and Pb6) that differ in their host range. Pb3 is highly virulent on B. napus (but also infects other Brassica species) while Pb6 infects only vegetable Brassica crops. Both the Pb3 and Pb6 genomes are highly compact, each with a total size of 24.2 Mb, and contain less than 2 % repetitive DNA. Clustering of genome-wide single nucleotide polymorphisms (SNP) of Pb3, Pb6 and three additional re-sequenced pathotypes (Pb2, Pb5 and Pb8) shows a high degree of correlation of cluster grouping with host range. The Pb3 genome features significant reduction of intergenic space with multiple examples of overlapping untranslated regions (UTRs). Dependency on the host for essential nutrients is evident from the loss of genes for the biosynthesis of thiamine and some amino acids and the presence of a wide range of transport proteins, including some unique to P. brassicae. The annotated genes of Pb3 include those with a potential role in the regulation of the plant growth hormones cytokinin and auxin. The expression profile of Pb3 genes, including putative effectors, during infection and their potential role in manipulation of host defence is discussed. The P. brassicae genome sequence reveals a compact genome, a dependency of the pathogen on its host for some

  12. Disease Severity Rating of Chile Pepper Plants Inoculated with Phytophthora Capsici Collected in Taiwan

    Data.gov (United States)

    US Agency for International Development — The data are the phenotypic host reactions of a recombinant inbred line population of Capsicum annuum developed to differentiate races of Phytophthora capsici. The...

  13. A test system to quantify inoculum in runoff from Phytophthora ramorum-infected plant roots

    Science.gov (United States)

    Nina. Shishkoff

    2010-01-01

    Foliar hosts of Phytophthora ramorum are often susceptible to root infection, but the epidemiological significance of such infections is unknown. We used a standardized test system to study inoculum in runoff from root-infected Viburnum tinus cuttings.

  14. Integrating cultural control methods for tomato late blight (Phytophthora infestans) in Uganda

    NARCIS (Netherlands)

    Tumwine, J.; Frinking, H.D.; Jeger, M.J.

    2002-01-01

    Cultural control measures against tomato late blight (Phytophthora infestans) were evaluated in six field experiments over 3 years in Uganda. Each experiment included sanitation (removal of diseased plant tissues), fungicide (mancozeb) application, and an untreated control, as standard treatments.

  15. AFLPs detect low genetic diversity for Phytophthora nemorosa and P. pseudosyringae in the US and Europe

    Science.gov (United States)

    Rachel E. Linzer; David M. Rizzo; Santa Olga Cacciola; Matteo Garbelotto

    2009-01-01

    In California and Oregon, two recently described oomycete forest pathogens, Phytophthora nemorosa and P. pseudosyringae, overlap in their host and geographic ranges with the virulent P. ramorum, causal agent of "sudden oak death." Epidemiological observations, namely broader geographic...

  16. Kaliumfosfiet helpt kalanchoë tegen phytophthora (interview met Filip van Noort)

    NARCIS (Netherlands)

    Neefjes, H.; Noort, van F.R.

    2009-01-01

    Toevoegen van plantversterker kaliumfosfiet maakt kalanchoë weerbaar tegen phytophthora. Onderzoek bij WUR Glastuinbouw heeft dit aangetoond in een deel van een proef. De praktijk is voorzichtig met het middel

  17. Is stump sprout treatment necessary to effectively control Phytophthora ramorum in California's wildlands?

    Science.gov (United States)

    Yana Valachovic; Richard Cobb; David Rizzo; Brendan Twieg; Chris Lee; Radoslaw Glebocki

    2013-01-01

    In California, wildland hosts that support sporulation of Phytophthora ramorum, such as California bay laurel (Umbellularia californica (Hook. & Arn.) Nutt.) and tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh), also develop prolific basal sprouts following...

  18. Microbiota Characterization of Compost Using Omics Approaches Opens New Perspectives for Phytophthora Root Rot Control

    OpenAIRE

    Blaya, Josefa; Marhuenda, Frutos C.; Pascual, Jose A.; Ros, Margarita

    2016-01-01

    Phytophthora root rot caused by Phytophthora nicotianae is an economically important disease in pepper crops. The use of suppressive composts is a low environmental impact method for its control. Although attempts have been made to reveal the relationship between microbiota and compost suppressiveness, little is known about the microorganisms associated with disease suppression. Here, an Ion Torrent platform was used to assess the microbial composition of composts made of different agro-indus...

  19. Multiple origins of downy mildews and mito-nuclear discordance within the paraphyletic genus Phytophthora

    Science.gov (United States)

    Choudhury, Robin A.; Mehl, Heather K.; Blomquist, Cheryl L.; McRoberts, Neil; Rizzo, David M.

    2018-01-01

    Phylogenetic relationships between thirteen species of downy mildew and 103 species of Phytophthora (plant-pathogenic oomycetes) were investigated with two nuclear and four mitochondrial loci, using several likelihood-based approaches. Three Phytophthora taxa and all downy mildew taxa were excluded from the previously recognized subgeneric clades of Phytophthora, though all were strongly supported within the paraphyletic genus. Downy mildews appear to be polyphyletic, with graminicolous downy mildews (GDM), brassicolous downy mildews (BDM) and downy mildews with colored conidia (DMCC) forming a clade with the previously unplaced Phytophthora taxon totara; downy mildews with pyriform haustoria (DMPH) were placed in their own clade with affinities to the obligate biotrophic P. cyperi. Results suggest the recognition of four additional clades within Phytophthora, but few relationships between clades could be resolved. Trees containing all twenty extant downy mildew genera were produced by adding partial coverage of seventeen additional downy mildew taxa; these trees supported the monophyly of the BDMs, DMCCs and DMPHs but suggested that the GDMs are paraphyletic in respect to the BDMs or polyphyletic. Incongruence between nuclear-only and mitochondrial-only trees suggests introgression may have occurred between several clades, particularly those containing biotrophs, questioning whether obligate biotrophic parasitism and other traits with polyphyletic distributions arose independently or were horizontally transferred. Phylogenetic approaches may be limited in their ability to resolve some of the complex relationships between the “subgeneric” clades of Phytophthora, which include twenty downy mildew genera and hundreds of species. PMID:29529094

  20. Membrane-based oligonucleotide array developed from multiple markers for the detection of many Phytophthora species.

    Science.gov (United States)

    Chen, Wen; Djama, Zeinab Robleh; Coffey, Michael D; Martin, Frank N; Bilodeau, Guillaume J; Radmer, Lorien; Denton, Geoff; Lévesque, C André

    2013-01-01

    Most Phytophthora spp. are destructive plant pathogens; therefore, effective monitoring and accurate early detection are important means of preventing potential epidemics and outbreaks of diseases. In the current study, a membrane-based oligonucleotide array was developed that can detect Phytophthora spp. reliably using three DNA regions; namely, the internal transcribed spacer (ITS), the 5' end of cytochrome c oxidase 1 gene (cox1), and the intergenic region between cytochrome c oxidase 2 gene (cox2) and cox1 (cox2-1 spacer). Each sequence data set contained ≈250 sequences representing 98 described and 15 undescribed species of Phytophthora. The array was validated with 143 pure cultures and 35 field samples. Together, nonrejected oligonucleotides from all three markers have the ability to reliably detect 82 described and 8 undescribed Phytophthora spp., including several quarantine or regulated pathogens such as Phytophthora ramorum. Our results showed that a DNA array containing signature oligonucleotides designed from multiple genomic regions provided robustness and redundancy for the detection and differentiation of closely related taxon groups. This array has the potential to be used as a routine diagnostic tool for Phytophthora spp. from complex environmental samples without the need for extensive growth of cultures.

  1. Pyrosequencing of environmental soil samples reveals biodiversity of the Phytophthora resident community in chestnut forests.

    Science.gov (United States)

    Vannini, Andrea; Bruni, Natalia; Tomassini, Alessia; Franceschini, Selma; Vettraino, Anna Maria

    2013-09-01

    Pyrosequencing analysis was performed on soils from Italian chestnut groves to evaluate the diversity of the resident Phytophthora community. Sequences analysed with a custom database discriminated 15 pathogenic Phytophthoras including species common to chestnut soils, while a total of nine species were detected with baiting. The two sites studied differed in Phytophthora diversity and the presence of specific taxa responded to specific ecological traits of the sites. Furthermore, some species not previously recorded were represented by a discrete number of reads; among these species, Phytophthora ramorum was detected at both sites. Pyrosequencing was demonstrated to be a very sensitive technique to describe the Phytophthora community in soil and was able to detect species not easy to be isolated from soil with standard baiting techniques. In particular, pyrosequencing is an highly efficient tool for investigating the colonization of new environments by alien species, and for ecological and adaptive studies coupled with biological detection methods. This study represents the first application of pyrosequencing for describing Phytophthoras in environmental soil samples. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  2. FACTORES QUE INCIDEN EN LA LIBERACIÓN DE ZOOSPORAS DE Spongospora subterranea (Wallroth Lagerheim f. sp. subterranea Tomlinson FACTORS AFECTING THE ZOOSPORE RELEASE OF Spongospora subterranean (Wallroth Lagerheim f. sp. subterranea Tomlinson

    Directory of Open Access Journals (Sweden)

    Daniel Esteban Alzate Velez

    2008-12-01

    Full Text Available Spongospora subterranea (Wallroth Lagerheim f. sp. subterranea Tomlinson es el agente causal de la sarna polvosa de la papa. Este patógeno es un protozoario, su infección ocurre por medio de zoosporas las cuales se liberan a partir de quistosoros y son el principal modo de dispersión de la enfermedad. Estos pueden encontrarse en tubérculos, raíces y el suelo, donde permanecen como estructuras de resistencia por varios años, hasta cuando las condiciones ambientales favorecen la liberación de zoosporas, para dar inicio a nuevas infecciones. En este trabajo, se evaluó el efecto de los exudados de raíz de papa, temperatura y fuente de inóculo con quistosoros aislados de suelo, raíz y tubérculo con el objetivo de verificar las condiciones en las cuales ocurre la liberación de zoosporas. Para tal fin se realizaron dos experimentos, en el primero se evaluó el efecto del agua y extracto de raíces y en el segundo el extracto de raíces y las diferentes fuentes de inóculo. Las evaluaciones se hicieron por conteo de zoosporas móviles durante 120 horas cada 24 horas. Se observó que el exudado de raíz tiene una alta influencia en la liberación de zoosporas, la cual ocurre entre los 15 y 23 °C a partir de las 48 y hasta las 96 horas, no se detectaron diferencias entre las fuentes de inóculo, lo que indica que independiente de su origen, si existen las condiciones ambientales adecuadas los quistosoros, tienen la capacidad de liberar un número suficiente de zoosporas que potencialmente pueden iniciar el proceso de infección en el hospedero.Spongospora subterranea (Wallroth Lagerheim f. sp. subterranea Tomlinson is the causal agent of potato powdery scab. This pathogen is worldwide distributed on the potato fields, infections occurs by zoospores which are inside resting spores called sporeballs or cystosori which are the principal way of disease spread. Sporeballs can be found on tubers, roots and soil as resistance structure, that can

  3. Could nitrile derivatives of turnip (Brassica rapa) glucosinolates be Hepato-and/or cholangiotoxic in cattle?

    Science.gov (United States)

    Turnip (Brassica rapa ssp. rapa) and rape (Brassica napus ssp. biennis) and other brassica forage crops are generally regarded as “safe” feed for cattle during late summer and fall in New Zealand. However, when Pithomyces chartarum spore counts are high there are epidemics of sporidesmin toxicity (...

  4. Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan

    2011-01-01

    , representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying...... the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from...

  5. Proceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09: Phytophthoras in forests and natural ecosystems

    Science.gov (United States)

    E.M. Goheen; S.J. Frankel

    2009-01-01

    The fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09, Phytophthoras in Forests and Natural Ecosystems provided a forum for current research on Phytophthora species worldwide. Seventy-eight submissions describing papers and posters on recent developments in Phytophthora diseases of trees and natural ecosystems in...

  6. Infection of Phytophthora palmivora from Soil in Cocoa Plantation

    Directory of Open Access Journals (Sweden)

    Agus Purwantara

    2008-12-01

    Full Text Available Phytophthora palmivora causes serious losses on cocoa in Indonesia and world-wide. The research aimed to assess the potential of soil as source of inocula for Phytophthora diseases in cocoa. Soil samples were baited using a healthy cocoa pod tissue, and the pathogen was isolated for morphological and molecular identification. Baiting technique was successfully used to detect the presence of P. palmivora in soil samples, and this was confirmed by morphological and molecular identification. P. palmivora can be detected in soil in all year around in wet areas indicating that soil is a massive and consistent source of inocula. Surveys conducted on the soil of Amazonian, Amelonado and Trinitario blocks of various ages showed that P. palmivora can be found in old and young cocoa blocks, even as young as 3 or 4 years. P. palmivora infection from soil to the pods appears to be mainly through contact or rain splash. Baiting with whole healthy pods exposed at different heights above undisturbed litter and above bare soil showed that the infection still occurred at 100 cm above the soil, even though it decreased gradually with the height. Infection from litter was not different to that from bare soil, indicating that the litter layer is not acting physically as a shield preventing rain from splashing the inocula up from wet soil to the pods. However, in tests for the possibility of P. palmivora carried through air convection, no pod was found to be infected, suggesting that the pathogen was not carried through convective accend of aerosol droplets from soil surface up to pods in the canopy.Key words : Theobroma cacao, pod rot, stem canker, baiting.

  7. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis fruits in Vietnam.

    Directory of Open Access Journals (Sweden)

    Ivana Puglisi

    Full Text Available Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis, a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana rootstocks grafted with 'King' mandarin (Citrus nobilis and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi, sweet orange (Citrus x sinensis and bergamot (Citrus x bergamia as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata. This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  8. The hidden duplication past of the plant pathogen Phytophthora and its consequences for infection

    Directory of Open Access Journals (Sweden)

    Martens Cindy

    2010-06-01

    Full Text Available Abstract Background Oomycetes of the genus Phytophthora are pathogens that infect a wide range of plant species. For dicot hosts such as tomato, potato and soybean, Phytophthora is even the most important pathogen. Previous analyses of Phytophthora genomes uncovered many genes, large gene families and large genome sizes that can partially be explained by significant repeat expansion patterns. Results Analysis of the complete genomes of three different Phytophthora species, using a newly developed approach, unveiled a large number of small duplicated blocks, mainly consisting of two or three consecutive genes. Further analysis of these duplicated genes and comparison with the known gene and genome duplication history of ten other eukaryotes including parasites, algae, plants, fungi, vertebrates and invertebrates, suggests that the ancestor of P. infestans, P. sojae and P. ramorum most likely underwent a whole genome duplication (WGD. Genes that have survived in duplicate are mainly genes that are known to be preferentially retained following WGDs, but also genes important for pathogenicity and infection of the different hosts seem to have been retained in excess. As a result, the WGD might have contributed to the evolutionary and pathogenic success of Phytophthora. Conclusions The fact that we find many small blocks of duplicated genes indicates that the genomes of Phytophthora species have been heavily rearranged following the WGD. Most likely, the high repeat content in these genomes have played an important role in this rearrangement process. As a consequence, the paucity of retained larger duplicated blocks has greatly complicated previous attempts to detect remnants of a large-scale duplication event in Phytophthora. However, as we show here, our newly developed strategy to identify very small duplicated blocks might be a useful approach to uncover ancient polyploidy events, in particular for heavily rearranged genomes.

  9. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis) fruits in Vietnam.

    Science.gov (United States)

    Puglisi, Ivana; De Patrizio, Alessandro; Schena, Leonardo; Jung, Thomas; Evoli, Maria; Pane, Antonella; Van Hoa, Nguyen; Van Tri, Mai; Wright, Sandra; Ramstedt, Mauritz; Olsson, Christer; Faedda, Roberto; Magnano di San Lio, Gaetano; Cacciola, Santa Olga

    2017-01-01

    Two distinct Phytophthora taxa were found to be associated with brown rot of pomelo (Citrus grandis), a new disease of this ancestral Citrus species, in the Vinh Long province, Mekong River Delta area, southern Vietnam. On the basis of morphological characters and using the ITS1-5.8S-ITS2 region of the rDNA and the cytochrome oxidase subunit 1 (COI) as barcode genes, one of the two taxa was provisionally named as Phytophthora sp. prodigiosa, being closely related to but distinct from P. insolita, a species in Phytophthora Clade 9, while the other one, was closely related to but distinct from the Clade 2 species P. meadii and was informally designated as Phytophthora sp. mekongensis. Isolates of P. sp. prodigiosa and P. sp. mekongensis were also obtained from necrotic fibrous roots of Volkamer lemon (C. volkameriana) rootstocks grafted with 'King' mandarin (Citrus nobilis) and from trees of pomelo, respectively, in other provinces of the Mekong River Delta, indicating a widespread occurrence of both Phytophthora species in this citrus-growing area. Koch's postulates were fulfilled via pathogenicity tests on fruits of various Citrus species, including pomelo, grapefruit (Citrus x paradisi), sweet orange (Citrus x sinensis) and bergamot (Citrus x bergamia) as well as on the rootstock of 2-year-old trees of pomelo and sweet orange on 'Carrizo' citrange (C. sinensis 'Washington Navel' x Poncirus trifoliata). This is the first report of a Phytophthora species from Clade 2 other than P. citricola and P. citrophthora as causal agent of fruit brown rot of Citrus worldwide and the first report of P. insolita complex in Vietnam. Results indicate that likely Vietnam is still an unexplored reservoir of Phytophthora diversity.

  10. Reduction of antinutritional glucosinolates in Brassica oilseeds by mutation of genes encoding transporters

    DEFF Research Database (Denmark)

    Nour-Eldin, Hussam Hassan; Madsen, Svend Roesen; Engelen, Steven

    2017-01-01

    The nutritional value of Brassica seed meals is reduced by the presence of glucosinolates, which are toxic compounds involved in plant defense. Mutation of the genes encoding two glucosinolate transporters (GTRs) eliminated glucosinolates from Arabidopsis thaliana seeds, but translation of loss......-of-function phenotypes into Brassica crops is challenging because Brassica is polyploid. We mutated one of seven and four of 12 GTR orthologs and reduced glucosinolate levels in seeds by 60-70% in two different Brassica species (Brassica rapa and Brassica juncea). Reduction in seed glucosinolates was stably inherited...... over multiple generations and maintained in field trials of two mutant populations at three locations. Successful translation of the gtr loss-of-function phenotype from model plant to two Brassica crops suggests that our transport engineering approach could be broadly applied to reduce seed...

  11. Light influence in the nutritional composition of Brassica oleracea sprouts.

    Science.gov (United States)

    Vale, A P; Santos, J; Brito, N V; Peixoto, V; Carvalho, Rosa; Rosa, E; Oliveira, M Beatriz P P

    2015-07-01

    Brassica sprouts are considered a healthy food product, whose nutritional quality can be influenced by several factors. The aim of this work was to monitor the nutritional composition changes promoted by different sprouting conditions of four varieties of Brassica oleracea (red cabbage, broccoli, Galega kale and Penca cabbage). Sprouts were grown under light/darkness cycles and complete darkness. Standard AOAC methods were applied for nutritional value evaluation, while chromatographic methods with UV-VIS and FID detection were used to determine the free amino acids and fatty acids, respectively. Mineral content was analyzed by atomic absorption spectrometry. Sprouts composition revealed them as an excellent source of protein and dietary fiber. Selenium content was one of the most distinctive feature of sprouts, being the sprouting conditions determinant for the free amino acid and fatty acids profile. The use of complete darkness was beneficial to the overall nutritional quality of the brassica sprouts studied. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Phosphate-assisted phytoremediation of arsenic by Brassica napus and Brassica juncea: Morphological and physiological response.

    Science.gov (United States)

    Niazi, Nabeel Khan; Bibi, Irshad; Fatimah, Ayesha; Shahid, Muhammad; Javed, Muhammad Tariq; Wang, Hailong; Ok, Yong Sik; Bashir, Safdar; Murtaza, Behzad; Saqib, Zulfiqar Ahmad; Shakoor, Muhammad Bilal

    2017-07-03

    In this study, we examined the potential role of phosphate (P; 0, 50, 100 mg kg -1 ) on growth, gas exchange attributes, and photosynthetic pigments of Brassica napus and Brassica juncea under arsenic (As) stress (0, 25, 50, 75 mg kg -1 ) in a pot experiment. Results revealed that phosphate supplementation (P100) to As-stressed plants significantly increased shoot As concentration, dry biomass yield, and As uptake, in addition to the improved morphological and gas exchange attributes and photosynthetic pigments over P0. However, phosphate-assisted increase in As uptake was substantially (up to two times) greater for B. napus, notably due to higher shoot As concentration and dry biomass yield, compared to B. juncea at the P100 level. While phosphate addition in soil (P100) led to enhanced shoot As concentration in B. juncea, it reduced shoot dry biomass, primarily after 50 and 75 mg kg -1 As treatments. The translocation factor and bioconcentration factor values of B. napus were higher than B. juncea for all As levels in the presence of phosphate. This study demonstrates that phosphate supplementation has a potential to improve As phytoextraction efficiency, predominantly for B. napus, by minimizing As-induced damage to plant growth, as well as by improving the physiological and photosynthetic attributes.

  13. Effects of Phytophthora cinnamomi isolate, inoculum delivery method, flood, and drought on vigor, disease severity and mortality of blueberry plants

    Science.gov (United States)

    Four studies evaluated the effect of Phytophthora cinnamomi isolates, inoculum delivery methods, and flood and drought conditions on vigor, disease severity scores, and survival of blueberry plants grown in pots in the greenhouse. Phytophthora cinnamomi isolates were obtained from blueberry plants ...

  14. Using single strand conformational polymorphisms (SSCP) to identify Phytophthora species in Oregon forests affected by sudden oak death

    Science.gov (United States)

    E. Hansen; C. Hesse; P. Reeser; W. Sutton; L. Winton

    2006-01-01

    Phytophthora species are abundant in streams, widespread in soils and occasionally found in diseased plants in the tanoak forests of southwestern Oregon. It is time-consuming and expensive to identify hundreds of isolates to species using morphology or internal transribed spacer (ITS) sequencing. We modified a published Phytophthora...

  15. Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across Southeastern United States (NC, SC, and GA)

    Science.gov (United States)

    Phytophthora capsici has been documented as a pathogen on a wide variety of vegetable crops in the family Solanaceae, Cucurbitaceae, Fabaceae, and plants belonging to 23 other families. Phytophthora fruit rot of watermelons caused by P. capsici is particularly severe in southeastern U.S where optima...

  16. Dendritic cells pulsed with Pythium insidiosum (1,3)(1,6)-β-glucan, Heat-inactivated zoospores and immunotherapy prime naïve T cells to Th1 differentiation in vitro.

    Science.gov (United States)

    Ledur, Pauline C; Tondolo, Juliana S M; Jesus, Francielli P K; Verdi, Camila M; Loreto, Érico S; Alves, Sydney H; Santurio, Janio M

    2018-03-01

    Pythiosis is a life-threatening disease caused by the fungus-like microorganism Pythium insidiosum that can lead to death if not treated. Since P. insidiosum has particular cell wall characteristics, pythiosis is difficult to treat, as it does not respond well to traditional antifungal drugs. In our study, we investigated a new immunotherapeutic approach with potential use in treatment and in the acquisition of immunity against pythiosis. Dendritic cells from both human and mouse, pulsed with P. insidiosum heat-inactivated zoospore, (1,3)(1,6)-β-glucan and the immunotherapeutic PitiumVac ® efficiently induced naïve T cell differentiation in a Th1 phenotype by the activation of specific Th1 cytokine production in vitro. Heat-inactivated zoospores showed the greatest Th1 response among the tested groups, with a significant increase in IL-6 and IFN-γ production in human cells. In mice cells, we also observed a Th17 pathway induction, with an increase on the IL-17A levels in lymphocytes cultured with β-glucan pulsed DCs. These results suggest a potential use of DCs pulsed with P. insidiosum antigens as a new therapeutic strategy in the treatment and acquisition of immunity against pythiosis. Copyright © 2017 Elsevier GmbH. All rights reserved.

  17. Phytophthora terminalis sp. nov. and Phytophthora occultans sp. nov., two invasive pathogens of ornamental plants in Europe.

    Science.gov (United States)

    Man In 't Veld, Willem A; Rosendahl, Karin C H M; van Rijswick, Patricia C J; Meffert, Johan P; Westenberg, Marcel; van de Vossenberg, Bart T L H; Denton, Geoff; van Kuik, Fons A J

    2015-01-01

    In the past decade several Phytophthora strains were isolated from diseased Pachysandra terminalis plants suffering stem base and root rot, originating from the Netherlands and Belgium. All isolates were homothallic and had a felt-like colony pattern, produced semi-papillate sporangia, globose oogonia and had a maximum growth at ~ 27 C. Several additional Phytophthora strains were isolated from diseased Buxus sempervirens plants, originating from the Netherlands and Belgium, which had sustained stem base and root rot; similar strains also were isolated from Acer palmatum, Choisya ternata and Taxus in the United Kingdom. All isolates were homothallic and had a stellate colony pattern, produced larger semi-papillate sporangia and smaller globose oogonia than the isolates from Pa. terminalis and had a maximum growth temperature of ~ 30 C. Phylogenetic analyses of both species using the internal transcribed spacer region of the nuc rDNA (ITS), mt cytochrome oxidases subunit I gene (CoxI) and nuc translation elongation factor 1-α gene (TEF1α) revealed that all sequences of each species were identical at each locus and unique to that species, forming two distinct clusters in subclade 2a. Sequence analysis of partial β-tubulin genes showed that both taxa share an identical sequence that is identical to that of Ph. himalsilva, a species originating from Asia, suggesting a common Asian origin. Pathogenicity trials demonstrated disease symptoms on their respective hosts, and re-isolation and re-identification of the inoculated pathogens confirmed Koch's postulates. © 2015 by The Mycological Society of America.

  18. Induced polyploidization in Brassica campestris L. (Brassicaceae).

    Science.gov (United States)

    Kumar, G; Dwivedi, K

    2014-01-01

    Present experimental design has been made up to obtain crop with higher ploidy level via synthetic polyploidization. Since ploidy manipulation is generally associated with the obtainment of some increased enviable traits of the crop and also provides them greater adaptability to unfavorable or harsh circumstances as compared to its diploids counterparts. Thus, herein present research autotetraploids of Brassica campestris L. have been lucratively achieved by the application of colchicine. Two methods of treatment were utilized i.e. seed treatment and seedling treatment. No polyploidy could be obtained through seed treatment while seedling treatment responded well towards polyploidy. However, the status of autotetraploidy has been confirmed by cytomorphological investigations of treated plants as against its diploids counterparts. For the purpose, morphological parameters such as increased stomata size, pollen diameter, flower size, reproductive organs whereas reduction in plant height, leaf length, leaf breadth, stomata frequency, number of flowers/inflorescence etc. were appraised. Further, cytological observations were made that had clearly revealed the doubling of genome in the autotetraploids as compared to diploids. Meanwhile, pollen fertility and size of pollen grains were evaluated as well.

  19. Profiling Gene Expression in Germinating Brassica Roots.

    Science.gov (United States)

    Park, Myoung Ryoul; Wang, Yi-Hong; Hasenstein, Karl H

    2014-01-01

    Based on previously developed solid-phase gene extraction (SPGE) we examined the mRNA profile in primary roots of Brassica rapa seedlings for highly expressed genes like ACT7 (actin7), TUB (tubulin1), UBQ (ubiquitin), and low expressed GLK (glucokinase) during the first day post-germination. The assessment was based on the mRNA load of the SPGE probe of about 2.1 ng. The number of copies of the investigated genes changed spatially along the length of primary roots. The expression level of all genes differed significantly at each sample position. Among the examined genes ACT7 expression was most even along the root. UBQ was highest at the tip and root-shoot junction (RS). TUB and GLK showed a basipetal gradient. The temporal expression of UBQ was highest in the MZ 9 h after primary root emergence and higher than at any other sample position. Expressions of GLK in EZ and RS increased gradually over time. SPGE extraction is the result of oligo-dT and oligo-dA hybridization and the results illustrate that SPGE can be used for gene expression profiling at high spatial and temporal resolution. SPGE needles can be used within two weeks when stored at 4 °C. Our data indicate that gene expression studies that are based on the entire root miss important differences in gene expression that SPGE is able to resolve for example growth adjustments during gravitropism.

  20. The broccoli (Brassica oleracea) phloem tissue proteome.

    Science.gov (United States)

    Anstead, James A; Hartson, Steven D; Thompson, Gary A

    2013-11-07

    The transport of sugars, hormones, amino acids, proteins, sugar alcohols, and other organic compounds from the sites of synthesis to the sites of use or storage occurs through the conducting cells of the phloem. To better understand these processes a comprehensive understanding of the proteins involved is required. While a considerable amount of data has been obtained from proteomic analyses of phloem sap, this has mainly served to identify the soluble proteins that are translocated through the phloem network. In order to obtain more comprehensive proteomic data from phloem tissue we developed a simple dissection procedure to isolate phloem tissue from Brassica oleracea. The presence of a high density of phloem sieve elements was confirmed using light microscopy and fluorescently labeled sieve element-specific antibodies. To increase the depth of the proteomic analysis for membrane bound and associated proteins, soluble proteins were extracted first and subsequent extractions were carried out using two different detergents (SDS and CHAPSO). Across all three extractions almost four hundred proteins were identified and each extraction method added to the analysis demonstrating the utility of an approach combining several extraction protocols. The phloem was found to be enriched in proteins associated with biotic and abiotic stress responses and structural proteins. Subsequent expression analysis identified a number of genes that appear to be expressed exclusively or at very high levels in phloem tissue, including genes that are known to express specifically in the phloem as well as novel phloem genes.

  1. Phytophthora community structure analyses in Oregon nurseries inform systems approaches to disease management.

    Science.gov (United States)

    Parke, Jennifer L; Knaus, Brian J; Fieland, Valerie J; Lewis, Carrie; Grünwald, Niklaus J

    2014-10-01

    Nursery plants are important vectors for plant pathogens. Understanding what pathogens occur in nurseries in different production stages can be useful to the development of integrated systems approaches. Four horticultural nurseries in Oregon were sampled every 2 months for 4 years to determine the identity and community structure of Phytophthora spp. associated with different sources and stages in the nursery production cycle. Plants, potting media, used containers, water, greenhouse soil, and container yard substrates were systematically sampled from propagation to the field. From 674 Phytophthora isolates recovered, 28 different species or taxa were identified. The most commonly isolated species from plants were Phytophthora plurivora (33%), P. cinnamomi (26%), P. syringae (19%), and P. citrophthora (11%). From soil and gravel substrates, P. plurivora accounted for 25% of the isolates, with P. taxon Pgchlamydo, P. cryptogea, and P. cinnamomi accounting for 18, 17, and 15%, respectively. Five species (P. plurivora, P. syringae, P. taxon Pgchlamydo, P. gonapodyides, and P. cryptogea) were found in all nurseries. The greatest diversity of taxa occurred in irrigation water reservoirs (20 taxa), with the majority of isolates belonging to internal transcribed spacer clade 6, typically including aquatic opportunists. Nurseries differed in composition of Phytophthora communities across years, seasons, and source within the nursery. These findings suggest likely contamination hazards and target critical control points for management of Phytophthora disease using a systems approach.

  2. Phytophthora pseudopolonica sp. nov., a new species recovered from stream water in subtropical forests of China.

    Science.gov (United States)

    Li, Wen-Wen; Zhao, Wen-Xia; Huai, Wen-Xia

    2017-09-01

    A new species of the genus Phytophthora was isolated from stream water in the subtropical forests of China during a survey of forest Phytophthora from 2011 to 2013. This new species is formally described here and named Phytophthora pseudopolonica sp. nov. This new homothallic species is distinct from other known Phytophthora species in morphology and produces nonpapillate and noncaducous sporangia with internal proliferation. Spherical hyphal swellings and thin-walled chlamydospores are abundant when the species is kept in sterile water. The P. pseudopolonica sp. nov. forms smooth oogonia with paragynous and sometimes amphigynous antheridia. The optimum growth temperature of the species is 30 °C in V8-juice agar with β-sitosterol, yet it barely grows at 5 °C and 35 °C. Based on sequences of the internal transcribed spacer and the combined β-tubulin and elongation factor 1α gene sequence data, isolates of the new species cluster together into a single branch and are close to Phytophthora polonicabelonging to clade 9.

  3. Multiple Phytophthora species associated with a single riparian ecosystem in South Africa.

    Science.gov (United States)

    Nagel, Jan H; Slippers, Bernard; Wingfield, Michael J; Gryzenhout, Marieka

    2015-01-01

    The diversity of Phytophthora spp. in rivers and riparian ecosystems has received considerable international attention, although little such research has been conducted in South Africa. This study determined the diversity of Phytophthora spp. within a single river in Gauteng province of South Africa. Samples were collected over 1 y including biweekly river baiting with Rhododendron indicum leaves. Phytophthora isolates were identified with phylogenetic analyses of sequences for the internal transcribed spacer (ITS) region of the ribosomal DNA and the mitochondrial cytochrome oxidase c subunit I (coxI) gene. Eight Phytophthora spp. were identified, including a new taxon, P. taxon Sisulu-river, and two hybrid species from Cooke's ITS clade 6. Of these, species from Clade 6 were the most abundant, including P. chlamydospora and P. lacustris. Species residing in Clade 2 also were encountered, including P. multivora, P. plurivora and P. citrophthora. The detection of eight species in this investigation of Phytophthora diversity in a single riparian river ecosystem in northern South Africa adds to the known diversity of this genus in South Africa and globally. © 2015 by The Mycological Society of America.

  4. Metabarcoding Analysis of Phytophthora Diversity Using Genus-Specific Primers and 454 Pyrosequencing.

    Science.gov (United States)

    Prigigallo, Maria I; Abdelfattah, Ahmed; Cacciola, Santa O; Faedda, Roberto; Sanzani, Simona M; Cooke, David E L; Schena, L

    2016-03-01

    A metabarcoding method based on genus-specific primers and 454 pyrosequencing was utilized to investigate the genetic diversity of Phytophthora spp. in soil and root samples of potted plants, from eight nurseries. Pyrosequencing enabled the detection of 25 Phytophthora phylotypes distributed in seven different clades and provided a much higher resolution than a corresponding cloning/Sanger sequencing approach. Eleven of these phylotypes, including P. cactorum, P. citricola s.str., P. palmivora, P. palmivora-like, P. megasperma or P. gonapodyides, P. ramorum, and five putative new Phytophthora species phylogenetically related to clades 1, 2, 4, 6, and 7 were detected only with the 454 pyrosequencing approach. We also found an additional 18 novel records of a phylotype in a particular nursery that were not detected with cloning/Sanger sequencing. Several aspects confirmed the reliability of the method: (i) many identical sequence types were identified independently in different nurseries, (ii) most sequence types identified with 454 pyrosequencing were identical to those from the cloning/Sanger sequencing approach and/or perfectly matched GenBank deposited sequences, and (iii) the divergence noted between sequence types of putative new Phytophthora species and all other detected sequences was sufficient to rule out sequencing errors. The proposed method represents a powerful tool to study Phytophthora diversity providing that particular attention is paid to the analysis of 454 pyrosequencing raw read sequences and to the identification of sequence types.

  5. Genome-wide microsatellite characterization and marker development in the sequenced Brassica crop species.

    Science.gov (United States)

    Shi, Jiaqin; Huang, Shunmou; Zhan, Jiepeng; Yu, Jingyin; Wang, Xinfa; Hua, Wei; Liu, Shengyi; Liu, Guihua; Wang, Hanzhong

    2014-02-01

    Although much research has been conducted, the pattern of microsatellite distribution has remained ambiguous, and the development/utilization of microsatellite markers has still been limited/inefficient in Brassica, due to the lack of genome sequences. In view of this, we conducted genome-wide microsatellite characterization and marker development in three recently sequenced Brassica crops: Brassica rapa, Brassica oleracea and Brassica napus. The analysed microsatellite characteristics of these Brassica species were highly similar or almost identical, which suggests that the pattern of microsatellite distribution is likely conservative in Brassica. The genomic distribution of microsatellites was highly non-uniform and positively or negatively correlated with genes or transposable elements, respectively. Of the total of 115 869, 185 662 and 356 522 simple sequence repeat (SSR) markers developed with high frequencies (408.2, 343.8 and 356.2 per Mb or one every 2.45, 2.91 and 2.81 kb, respectively), most represented new SSR markers, the majority had determined physical positions, and a large number were genic or putative single-locus SSR markers. We also constructed a comprehensive database for the newly developed SSR markers, which was integrated with public Brassica SSR markers and annotated genome components. The genome-wide SSR markers developed in this study provide a useful tool to extend the annotated genome resources of sequenced Brassica species to genetic study/breeding in different Brassica species.

  6. Genetic variability among advanced lines of brassica

    International Nuclear Information System (INIS)

    Ullah, N.; Farhatullah, A.; Rahman, H.U.; Fayyaz, L.

    2015-01-01

    Genetic variability for morphological and biochemical traits among six advanced lines (F10:11) of brassica was studied at The University of Agriculture Peshawar during crop season of 2012-13. These lines were developed through interspecific hybridization. Significant differences at (p=0.01) for plant height, main, pods main raceme-1, pod length, seed yield plant-1 and protein content at (p=0.05) for 100-seed weight, oil content were recorded. The advanced line, AUP-05 produced the maximum seed yield plant-1 (19.73 g), protein content (24.56%), 100-seed weight (0.64 g). Advanced line AUP-04 had the highest erucic acid (50.31%), linolenic acid (10.60%) and was late maturing (179.33). Advanced line AUP-06 produced the high oil content (48.82%). Advanced line AUP-03 produced comparatively longer main raceme (69.32 cm). Environmental variance was smaller than genotypic variance for majority of the traits. Genotypic and phenotypic coefficients of variation ranged from 2.45 to 25.67% and 2.50 to 27.68%, respectively. Heritability was high for majority of the traits. The maximum heritability was recorded for plant height (0.61), main raceme length (0.81), pods main raceme-1 (0.74), seed yield plant-1 (0.86) and protein content (0.77). Moderate heritability was observed for oil (0.58) contents. Heritability for 100-seed weight (0.30) was the lowest. These lines may be released as new improved varieties for specific parameters. (author)

  7. Oxygen dependency of germinating Brassica seeds

    Science.gov (United States)

    Park, Myoung Ryoul; Hasenstein, Karl H.

    2016-02-01

    Establishing plants in space, Moon or Mars requires adaptation to altered conditions, including reduced pressure and composition of atmospheres. To determine the oxygen requirements for seed germination, we imbibed Brassica rapa seeds under varying oxygen concentrations and profiled the transcription patterns of genes related to early metabolism such as starch degradation, glycolysis, and fermentation. We also analyzed the activity of lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH), and measured starch degradation. Partial oxygen pressure (pO2) greater than 10% resulted in normal germination (i.e., protrusion of radicle about 18 hours after imbibition) but lower pO2 delayed and reduced germination. Imbibition in an oxygen-free atmosphere for three days resulted in no germination but subsequent transfer to air initiated germination in 75% of the seeds and the root growth rate was transiently greater than in roots germinated under ambient pO2. In hypoxic seeds soluble sugars degraded faster but the content of starch after 24 h was higher than at ambient oxygen. Transcription of genes related to starch degradation, α-amylase (AMY) and Sucrose Synthase (SUS), was higher under ambient O2 than under hypoxia. Glycolysis and fermentation pathway-related genes, glucose phosphate isomerase (GPI), 6-phosphofructokinase (PFK), fructose 1,6-bisphosphate aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate decarboxylase (PDC), LDH, and ADH, were induced by low pO2. The activity of LDH and ADH was the highest in anoxic seeds. Germination under low O2 conditions initiated ethanolic fermentation. Therefore, sufficient oxygen availability is important for germination before photosynthesis provides necessary oxygen and the determination of an oxygen carrying capacity is important for uniform growth in space conditions.

  8. Plant regeneration of Brassica oleracea subsp. italica (Broccoli) CV ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-03

    Jun 3, 2009 ... Department of Agriculture Technology, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul. Ehsan, Malaysia. Accepted 20 March, 2009. Hypocotyls and shoot tips were used as explants in in vitro plant regeneration of broccoli (Brassica oleracea subsp.italica) cv. Green Marvel.

  9. Processing of Brassica seeds for feedstock in biofuels production

    Science.gov (United States)

    Several Brassica species are currently being evaluated to develop regionalized production systems based on their suitability to the environment and with the prevailing practices of growing commodity food crops like wheat, corn, and soybeans. This integrated approach to farming will provide high qual...

  10. Genetic diversity analysis of mustard ( Brassica spp.) germplasm ...

    African Journals Online (AJOL)

    Molecular characterization of 16 mustard (Brassica spp.) genotypes by using 12 RAPD markers revealed that three primers GLA-11, OPB-04 and OPD-02 showed good technical resolution and sufficient variations among different genotypes. A total of 40 RAPD bands were scored of which 38 (94.87%) polymorphic ...

  11. Phytotoxicity assay for seed production using Brassica rapa L.

    Science.gov (United States)

    Although pesticide drift can affect crop yield adversely, current plant testing protocols emphasize only the potential impacts on vegetative plant growth. The present study was conducted to determine whether a plant species with a short life cycle, such as Brassica rapa L. Wiscon...

  12. Phenotyping of Brassica napus for high oil content

    Science.gov (United States)

    Multi-trait and multi-growth stage phenotyping may improve our ability to assess the dynamic changes in the B. napus phenome under spatiotemporal field conditions. A minimum set of phenotypic traits that can integrate ontogeny and architecture of Brassica napus L. is required for breeding and select...

  13. Study of total seed storage protein in indigenous Brassica species ...

    African Journals Online (AJOL)

    hope&shola

    2010-11-08

    Nov 8, 2010 ... Brassica napus. Acc. No Location. Acc. No Location. Acc. No Location. Acc. No Location. 500. Islamsbad. 522. Hassan Abdal. 544. Naseer abad. 566. Rawalpindi. 501. Islamsbad. 523. Bannu. 545. Jaglot. 567. Karak. 502. Rawalakot. 524. Karak. 546. Haripur North. 568. Akora Khattack. 503. Sibi. 525.

  14. Mineral, vitamin C and crude protein contents in kale ( Brassica ...

    African Journals Online (AJOL)

    This study compares mineral, vitamin C and crude protein contents at different harvesting stages in kale (Brassica oleraceae var. acephala). Three different harvest periods as first harvest stage (at the rosette stage), second harvest stage (at the budding stage) and third harvest stage (at the flowering/blooming stage) were ...

  15. Suitability of an artificial diet for rape aphid, Brevicoryne brassicae ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-15

    Sep 15, 2009 ... Brevicoryne brassicae, using life table parameters. A. Balvasi1* ... In this work, suitability of an artificial diet was studied through age-specific life tables. Development ... In large measure, the success of entomology over the past century is ..... balance on the improvement of an artificial diet for a biotype of.

  16. Molecular phylogenetic implications in Brassica napus based on ...

    Indian Academy of Sciences (India)

    Brassica napus L. (canola, rapeseed) is one of the most important oil crops in many countries (Abdelmigid 2012;. Fayyaz et al. 2014), and thought to have originated from a cross where the maternal donor was closely related to two diploid species, B. oleracea (CC, 2n = 18) and B. rapa (AA, 2n = 20). Here, molecular ...

  17. Occurrence of Escherichia coli in Brassica rapa L. chinensis ...

    African Journals Online (AJOL)

    Low quality water has become valuable resource with restricted or unrestricted use in food production depending on its quality. This study has quantified the occurrence of Escherichia coli in Brassica rapa L. chinensis (Chinese cabbage) vegetables and low quality irrigation water. A total of 106 samples including Chinese ...

  18. Glucosinolates during preparation of Brassica vegetables in Indonesia

    NARCIS (Netherlands)

    Nugrahedi, P.Y.

    2015-01-01

    Title:

    Glucosinolates during preparation of Brassica vegetables in Indonesia

    Dutch translation of title:

    Effecten van Indonesische bereidingsmethoden op gezondheidsbevorderende stoffen in groenten

    Title/description

  19. Molecular characterization of some local and exotic Brassica juncea ...

    African Journals Online (AJOL)

    SERVER

    2007-07-18

    Jul 18, 2007 ... 1Institute of Biotechnology and Genetic Engineering (IBGE) NWFP Agricultural University, Peshawar, Pakistan. 2Department of Plant Breeding and Genetics, NWFP Agricultural University Peshawar, Pakistan. Accepted 14 June, 2007. The production of Brassica germplasm with a wider genetic base is ...

  20. Local cabbage ( Brassica oleracea var. capitata L.) populations from ...

    African Journals Online (AJOL)

    In previous experiments, we were able to augment cabbages (Brassica oleracea L. var. capitata L.) with two new local open pollinated (OP) populations and one cultivar. The type of use indicated that these are cabbages with thinner and juicier leaves, which predisposes their heads for fine grating and also makes their ...

  1. Identification of seed-related QTL in Brassica rapa

    NARCIS (Netherlands)

    Bagheri, H.; Pino del Carpio, D.; Hanhart, C.J.; Bonnema, A.B.; Keurentjes, J.J.B.; Aarts, M.G.M.

    2013-01-01

    To reveal the genetic variation, and loci involved, for a range of seed-related traits, a new F2 mapping population was developed by crossing Brassica rapa ssp. parachinensis L58 (CaiXin) with B. rapa ssp. trilocularis R-o-18 (spring oil seed), both rapid flowering and self-compatible. A linkage map

  2. Factors affecting the density of Brassica napus seeds

    NARCIS (Netherlands)

    Young, L.; Jalink, H.; Denkert, R.; Reaney, M.

    2006-01-01

    Brassica napus seed is composed of low density oil (0.92 g.cm(-3)) and higher density solids (1.3-1.45 g.cm(-3)). Seed buoyant density may potentially be used to determine seed oil content and to separate seeds with different oil contents, however, we have found that seeds with the lowest buoyant

  3. Immunopurification and characterization of a rape ( Brassica napus L.)

    African Journals Online (AJOL)

    Lipase or triacylglycerol acylhydrolase (E.C.3.1.1.3) was purified to homogeneity from rapeseed-germinated cotyledons (Brassica napus L.). The purification scheme involved homogenization, centrifugation, ultracentrifugation and affinity chromatography using polyclonal antibodies raised against porcine pancreatic lipase.

  4. Respon Tiga Varietas Sawi (Brassica Rapa L.) Terhadap Cekaman Air

    OpenAIRE

    Moctava, Mohammad Aries; Koesriharti, Koesriharti; Maghfoer, Mochammad Dawam

    2013-01-01

    Kebutuhan air tanaman berbeda-beda tergantung pada jenis tanamannya. Ketersediaan air bagi tanaman yang tidak mencukupi akan mempengaruhi morfologi dan fisiologis sehingga pertumbuhan dan hasil tanaman. Tujuan dari penelitian mendapatkan varietas sawi (Brassica rapa L.) yang tahan terhadap cekaman air. Penelitian dilaksanakan pada bulan Oktober sampai dengan Desember 2012. Tempat penelitian Kebun Percobaan Fakultas Pertanian Brawijaya, Desa Jatikerto, Kabupaten Malang.Penelitian menggunakan ...

  5. Phytophthora species recovered from the Connecticut River Valley in Massachusetts, USA.

    Science.gov (United States)

    Brazee, Nicholas J; Wick, Robert L; Hulvey, Jonathan P

    2016-01-01

    Little is currently known about the assemblage of Phytophthora species in northeastern North America, representing a gap in our understanding of species incidence. Therefore, Phytophthora species were surveyed at 20 sites in Massachusetts, with 16 occurring in the Connecticut River Valley. Many of the sampled waterways were adjacent to active agricultural lands, yet were buffered by mature floodplain forests composed of Acer, Platanus, Populus and Ulmus. Isolates were recovered with three types of baits (rhododendron leaves, pear, green pepper) in 2013 and water filtration in 2014. Overall, 457 isolates of Phytophthora were recovered and based on morphological characters and rDNA internal transcribed spacer (ITS), β-tubulin (β-tub) and cytochrome oxidase c subunit I (cox1) sequences, 18 taxa were identified, including three new species: P. taxon intercalaris, P. taxon caryae and P. taxon pocumtuck. In addition, 49 isolates representing five species of Phytopythium also were identified. Water filtration captured a greater number of taxa (18) compared to leaf and fruit baits (12). Of the three bait types rhododendron leaves yielded the greatest number of isolates and taxa, followed by pear and green pepper, respectively. Despite the proximity to agricultural lands, none of the Phytophthora species baited are considered serious pathogens of vegetable crops in the region. However, many of the recovered species are known woody plant pathogens, including four species in the P. citricola s.l. complex that were identified: P. plurivora, P. citricola III, P. pini and a putative novel species, referred to here as P. taxon caryae. An additional novel species, P. taxon pocumtuck, is a close relative of P. borealis based on cox1 sequences. The results illustrate a high level of Phytophthora species richness in the Connecticut River Valley and that major rivers can serve as a source of inoculum for pathogenic Phytophthora species in the northeast. © 2016 by The Mycological

  6. Use of genome sequence data in the design and testing of SSR markers for Phytophthora species

    Directory of Open Access Journals (Sweden)

    Cardle Linda

    2008-12-01

    Full Text Available Abstract Background Microsatellites or single sequence repeats (SSRs are a powerful choice of marker in the study of Phytophthora population biology, epidemiology, ecology, genetics and evolution. A strategy was tested in which the publicly available unigene datasets extracted from genome sequences of P. infestans, P. sojae and P. ramorum were mined for candidate SSR markers that could be applied to a wide range of Phytophthora species. Results A first approach, aimed at the identification of polymorphic SSR loci common to many Phytophthora species, yielded 171 reliable sequences containing 211 SSRs. Microsatellites were identified from 16 target species representing the breadth of diversity across the genus. Repeat number ranged from 3 to 16 with most having seven repeats or less and four being the most commonly found. Trinucleotide repeats such as (AAGn, (AGGn and (AGCn were the most common followed by pentanucleotide, tetranucleotide and dinucleotide repeats. A second approach was aimed at the identification of useful loci common to a restricted number of species more closely related to P. sojae (P. alni, P. cambivora, P. europaea and P. fragariae. This analysis yielded 10 trinucleotide and 2 tetranucleotide SSRs which were repeated 4, 5 or 6 times. Conclusion Key studies on inter- and intra-specific variation of selected microsatellites remain. Despite the screening of conserved gene coding regions, the sequence diversity between species was high and the identification of useful SSR loci applicable to anything other than the most closely related pairs of Phytophthora species was challenging. That said, many novel SSR loci for species other than the three 'source species' (P. infestans, P. sojae and P. ramorum are reported, offering great potential for the investigation of Phytophthora populations. In addition to the presence of microsatellites, many of the amplified regions may represent useful molecular marker regions for other studies as

  7. Atmospheric H2S and SO2 as sulfur sources for Brassica juncea and Brassica rapa: Regulation of sulfur uptake and assimilation

    NARCIS (Netherlands)

    Aghajanzadeh, T.; Hawkesford, M.J.; De Kok, L.J.

    2016-01-01

    Brassica juncea and Brassica rapa were able to utilize foliarly absorbed H2S and SO2 as sulfur source for growth and resulted in a decreased sink capacity of the shoot for sulfur supplied by the root and subsequently in a partial decrease in sulfate uptake capacity of the roots. Sulfate-deprived

  8. Stage-specific gene expression during sexual development in Phytophthora infestans

    DEFF Research Database (Denmark)

    Fabritius, Anna-Liisa; Cvitanich, Cristina; Judelson, Howard S.

    2002-01-01

    Eight genes that are upregulated during sexual development in the heterothallic oomycete, Phytophthora infestans, were identified by suppression subtractive hybridization. Two genes showed very low but detectable expression in vegetative hyphae and became induced about 40- to >100-fold early...... revealed that the predicted products of three of the genes had similarity to proteins that influence RNA stability, namely a ribonuclease activator, the pumilio family of RNA-binding proteins and RNase H. The products of two other mating-induced genes resembled two types of Phytophthora proteins previously...

  9. Phenylalanine Ammonia Lyase Activity in Stem of Pepper (Capsicum annuum L.) Infected by Phytophthora capsici L.

    OpenAIRE

    KOC, Esra; USTUN, Ayşen Sulun

    2012-01-01

    In this study, PAL activity in stems of pepper (Capsicum annuum L.) plants infected by the root rot pathogen Phytophthora capsici-22 in a resistant (PM-702) and two susceptible (Kahramanmaraş-Hot (KM-Hot) and Demre-8) cultivar were studied. The response of the PAL activity in the resistant cultivar was faster and higher than in the susceptible cultivars (p < 0.01). The increase in production of  PAL upon Phytophthora capsici-22 were higher in the infected plants compared to the non-in...

  10. Functional analysis and tissue-differential expression of four FAD2 genes in amphidiploid Brassica napus derived from Brassica rapa and Brassica oleracea.

    Science.gov (United States)

    Lee, Kyeong-Ryeol; In Sohn, Soo; Jung, Jin Hee; Kim, Sun Hee; Roh, Kyung Hee; Kim, Jong-Bum; Suh, Mi Chung; Kim, Hyun Uk

    2013-12-01

    Fatty acid desaturase 2 (FAD2), which resides in the endoplasmic reticulum (ER), plays a crucial role in producing linoleic acid (18:2) through catalyzing the desaturation of oleic acid (18:1) by double bond formation at the delta 12 position. FAD2 catalyzes the first step needed for the production of polyunsaturated fatty acids found in the glycerolipids of cell membranes and the triacylglycerols in seeds. In this study, four FAD2 genes from amphidiploid Brassica napus genome were isolated by PCR amplification, with their enzymatic functions predicted by sequence analysis of the cDNAs. Fatty acid analysis of budding yeast transformed with each of the FAD2 genes showed that whereas BnFAD2-1, BnFAD2-2, and BnFAD2-4 are functional enzymes, and BnFAD2-3 is nonfunctional. The four FAD2 genes of B. napus originated from synthetic hybridization of its diploid progenitors Brassica rapa and Brassica oleracea, each of which has two FAD2 genes identical to those of B. napus. The BnFAD2-3 gene of B. napus, a nonfunctional pseudogene mutated by multiple nucleotide deletions and insertions, was inherited from B. rapa. All BnFAD2 isozymes except BnFAD2-3 localized to the ER. Nonfunctional BnFAD2-3 localized to the nucleus and chloroplasts. Four BnFAD2 genes can be classified on the basis of their expression patterns. © 2013.

  11. The response of transgenic Brassica species to salt stress: a review.

    Science.gov (United States)

    Shah, Nadil; Anwar, Sumera; Xu, Jingjing; Hou, Zhaoke; Salah, Akram; Khan, Shahbaz; Gong, Jianfang; Shang, Zhengwei; Qian, Li; Zhang, Chunyu

    2018-06-01

    Salt stress is considered one of the main abiotic factors to limit crop growth and productivity by affecting morpho-physiological and biochemical processes. Genetically, a number of salt tolerant Brassica varieties have been developed and introduced, but breeding of such varieties is time consuming. Therefore, current focus is on transgenic technology, which plays an important role in the development of salt tolerant varieties. Various salt tolerant genes have been characterized and incorporated into Brassica. Therefore, such genetic transformation of Brassica species is a significant step for improvement of crops, as well as conferring salt stress resistance qualities to Brassica species. Complete genome sequencing has made the task of genetically transforming Brassica species easier, by identifying desired candidate genes. The present review discusses relevant information about the principles which should be employed to develop transgenic Brassica species, and also will recommend tools for improved tolerance to salinity.

  12. Infection of a tomato cell culture by Phytophthora infestans; a versatile tool to study Phytophthora-host interactions

    Directory of Open Access Journals (Sweden)

    Charikleia Schoina

    2017-10-01

    Full Text Available Abstract Background The oomycete Phytophthora infestans causes late blight on potato and tomato. Despite extensive research, the P. infestans-host interaction is still poorly understood. To find new ways to further unravel this interaction we established a new infection system using MsK8 tomato cells. These cells grow in suspension and can be maintained as a stable cell line that is representative for tomato. Results MsK8 cells can host several Phytophthora species pathogenic on tomato. Species not pathogenic on tomato could not infect. Microscopy revealed that 16 h after inoculation up to 36% of the cells were infected. The majority were penetrated by a germ tube emerging from a cyst (i.e. primary infection while other cells were already showing secondary infections including haustoria. In incompatible interactions, MsK8 cells showed defense responses, namely reactive oxygen species production and cell death leading to a halt in pathogen spread at the single cell level. In compatible interactions, several P. infestans genes, including RXLR effector genes, were expressed and in both, compatible and incompatible interactions tomato genes involved in defense were differentially expressed. Conclusions Our results show that P. infestans can prosper as a pathogen in MsK8 cells; it not only infects, but also makes haustoria and sporulates, and it receives signals that activate gene expression. Moreover, MsK8 cells have the ability to support pathogen growth but also to defend themselves against infection in a similar way as whole plants. An advantage of MsK8 cells compared to leaves is the more synchronized infection, as all cells have an equal chance of being infected. Moreover, analyses and sampling of infected tissue can be performed in a non-destructive manner from early time points of infection onwards and as such the MsK8 infection system offers a potential platform for large-scale omics studies and activity screenings of inhibitory

  13. Contrasting microsatellite diversity in the evolutionary lineages of Phytophthora lateralis.

    Science.gov (United States)

    Vettraino, AnnaMaria; Brasier, Clive M; Webber, Joan F; Hansen, Everett M; Green, Sarah; Robin, Cecile; Tomassini, Alessia; Bruni, Natalia; Vannini, Andrea

    2017-02-01

    Following recent discovery of Phytophthora lateralis on native Chamaecyparis obtusa in Taiwan, four phenotypically distinct lineages were discriminated: the Taiwan J (TWJ) and Taiwan K (TWK) in Taiwan, the Pacific Northwest (PNW) in North America and Europe and the UK in west Scotland. Across the four lineages, we analysed 88 isolates from multiple sites for microsatellite diversity. Twenty-one multilocus genotypes (MLGs) were resolved with high levels of diversity of the TWK and PNW lineages. No alleles were shared between the PNW and the Taiwanese lineages. TWK was heterozygous at three loci, whereas TWJ isolates were homozygous apart from one isolate, which exhibited a unique allele also present in the TWK lineage. PNW lineage was heterozygous at three loci. The evidence suggests its origin may be a yet unknown Asian source. North American and European PNW isolates shared all their alleles and also a dominant MLG, consistent with a previous proposal that this lineage is a recent introduction into Europe from North America. The UK lineage was monomorphic and homozygous at all loci. It shared its alleles with the PNW and the TWJ and TWK lineages, hence a possible origin in a recent hybridisation event between a Taiwan lineage and PNW cannot be ruled out. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  14. Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

    Directory of Open Access Journals (Sweden)

    Sirjana Devi Shrestha

    Full Text Available The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076 with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

  15. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Science.gov (United States)

    Sahoo, Dipak K; Abeysekara, Nilwala S; Cianzio, Silvia R; Robertson, Alison E; Bhattacharyya, Madan K

    2017-01-01

    Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs) (F7 families) were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR)-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  16. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Directory of Open Access Journals (Sweden)

    Dipak K Sahoo

    Full Text Available Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs (F7 families were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  17. Quantification of Plasmodiophora brassicae Using a DNA-Based Soil Test Facilitates Sustainable Oilseed Rape Production

    OpenAIRE

    Ann-Charlotte Wallenhammar; Albin Gunnarson; Fredrik Hansson; Anders Jonsson

    2016-01-01

    Outbreaks of clubroot disease caused by the soil-borne obligate parasite Plasmodiophora brassicae are common in oilseed rape (OSR) in Sweden. A DNA-based soil testing service that identifies fields where P. brassicae poses a significant risk of clubroot infection is now commercially available. It was applied here in field surveys to monitor the prevalence of P. brassicae DNA in field soils intended for winter OSR production and winter OSR field experiments. In 2013 in Scania, prior to plantin...

  18. Phytophthora suppressor of RNA silencing 2 is a conserved RxLR effector that promotes infection in soybean and Arabidopsis thaliana.

    Science.gov (United States)

    Xiong, Qin; Ye, Wenwu; Choi, Duseok; Wong, James; Qiao, Yongli; Tao, Kai; Wang, Yuanchao; Ma, Wenbo

    2014-12-01

    The genus Phytophthora consists of notorious and emerging pathogens of economically important crops. Each Phytophthora genome encodes several hundreds of cytoplasmic effectors, which are believed to manipulate plant immune response inside the host cells. However, the majority of Phytophthora effectors remain functionally uncharacterized. We recently discovered two effectors from the soybean stem and root rot pathogen Phytophthora sojae with the activity to suppress RNA silencing in plants. These effectors are designated Phytophthora suppressor of RNA silencing (PSRs). Here, we report that the P. sojae PSR2 (PsPSR2) belongs to a conserved and widespread effector family in Phytophthora. A PsPSR2-like effector produced by P. infestans (PiPSR2) can also suppress RNA silencing in plants and promote Phytophthora infection, suggesting that the PSR2 family effectors have conserved functions in plant hosts. Using Agrobacterium rhizogenes-mediated hairy roots induction, we demonstrated that the expression of PsPSR2 rendered hypersusceptibility of soybean to P. sojae. Enhanced susceptibility was also observed in PsPSR2-expressing Arabidopsis thaliana plants during Phytophthora but not bacterial infection. These experiments provide strong evidence that PSR2 is a conserved Phytophthora effector family that performs important virulence functions specifically during Phytophthora infection of various plant hosts.

  19. Molecular breeding in Brassica for salt tolerance: importance of microsatellite (SSR) markers for molecular breeding in Brassica

    Science.gov (United States)

    Kumar, Manu; Choi, Ju-Young; Kumari, Nisha; Pareek, Ashwani; Kim, Seong-Ryong

    2015-01-01

    Salinity is one of the important abiotic factors for any crop management in irrigated as well as rainfed areas, which leads to poor harvests. This yield reduction in salt affected soils can be overcome by improving salt tolerance in crops or by soil reclamation. Salty soils can be reclaimed by leaching the salt or by cultivation of salt tolerance crops. Salt tolerance is a quantitative trait controlled by several genes. Poor knowledge about mechanism of its inheritance makes slow progress in its introgression into target crops. Brassica is known to be a good reclamation crop. Inter and intra specific variation within Brassica species shows potential of molecular breeding to raise salinity tolerant genotypes. Among the various molecular markers, SSR markers are getting high attention, since they are randomly sparsed, highly variable and show co-dominant inheritance. Furthermore, as sequencing techniques are improving and softwares to find SSR markers are being developed, SSR markers technology is also evolving rapidly. Comparative SSR marker studies targeting Arabidopsis thaliana and Brassica species which lie in the same family will further aid in studying the salt tolerance related QTLs and subsequent identification of the “candidate genes” and finding out the origin of important QTLs. Although, there are a few reports on molecular breeding for improving salt tolerance using molecular markers in Brassica species, usage of SSR markers has a big potential to improve salt tolerance in Brassica crops. In order to obtain best harvests, role of SSR marker driven breeding approaches play important role and it has been discussed in this review especially for the introgression of salt tolerance traits in crops. PMID:26388887

  20. Molecular breeding in Brassica for salt tolerance: importance of microsatellite (SSR) markers for molecular breeding in Brassica.

    Science.gov (United States)

    Kumar, Manu; Choi, Ju-Young; Kumari, Nisha; Pareek, Ashwani; Kim, Seong-Ryong

    2015-01-01

    Salinity is one of the important abiotic factors for any crop management in irrigated as well as rainfed areas, which leads to poor harvests. This yield reduction in salt affected soils can be overcome by improving salt tolerance in crops or by soil reclamation. Salty soils can be reclaimed by leaching the salt or by cultivation of salt tolerance crops. Salt tolerance is a quantitative trait controlled by several genes. Poor knowledge about mechanism of its inheritance makes slow progress in its introgression into target crops. Brassica is known to be a good reclamation crop. Inter and intra specific variation within Brassica species shows potential of molecular breeding to raise salinity tolerant genotypes. Among the various molecular markers, SSR markers are getting high attention, since they are randomly sparsed, highly variable and show co-dominant inheritance. Furthermore, as sequencing techniques are improving and softwares to find SSR markers are being developed, SSR markers technology is also evolving rapidly. Comparative SSR marker studies targeting Arabidopsis thaliana and Brassica species which lie in the same family will further aid in studying the salt tolerance related QTLs and subsequent identification of the "candidate genes" and finding out the origin of important QTLs. Although, there are a few reports on molecular breeding for improving salt tolerance using molecular markers in Brassica species, usage of SSR markers has a big potential to improve salt tolerance in Brassica crops. In order to obtain best harvests, role of SSR marker driven breeding approaches play important role and it has been discussed in this review especially for the introgression of salt tolerance traits in crops.

  1. The in vitro culture of Phytophthora infestans isolates occurring on the tomato - their pathogenicity and usefulness for artificial inoculations

    Directory of Open Access Journals (Sweden)

    Elżbieta Horodecka

    2013-12-01

    Full Text Available In investigations on the fungus, Phytophthora infestans, isolated from open air, field-grown tomatoes, particular attention was paid to the pathogenicity of 32 isolates and the suitability of 10 kinds of natural media. It is concluded that Phytophthora races in Poland have highly varied pathogenicities and that they belong to race 0 or 1. The races were divided into subgroups of various aggressiveness. It was found that the best medium to obtain an inoculum was the agar-oat medium without vitamin B1. Vitamin B1 as well as tomatine added to agar media stimulated growth, but inhibited sporulation of Phytophthora infestans.

  2. Radiation effects on Brassica seeds and seedlings

    Science.gov (United States)

    Deoli, Naresh; Hasenstein, Karl H.

    2016-07-01

    Space radiation consists of high energy charged particles and affects biological systems, but because of its stochastic, non-directional nature is difficult to replicate on Earth. Radiation damages biological systems acutely at high doses or cumulatively at low doses through progressive changes in DNA organization. These damages lead to death or cause of mutations. While radiation biology typically focuses on mammalian or human systems, little is known as to how radiation affects plants. In addition, energetic ion beams are widely used to generate new mutants in plants considering their high-LET (Linear Energy Transfer) as compared to gamma rays and X-rays. Understanding the effect of ionizing radiation on plant provides a basis for studying effects of radiation on biological systems and will help mitigate (space) radiation damage in plants. We exposed dry and imbibed Brassica rapa seeds and seedling roots to proton beams of varying qualities and compared the theoretical penetration range of different energy levels with observable growth response. We used 1, 2 and 3 MeV protons in air at the varying fluences to investigate the effect of direct irradiation on the seeds (1012 - 1015 ions/cm2) and seedlings (1013 ions/cm2). The range of protons in the tissue was calculated using Monte-Carlo based SRIM (Stopping and Range of Ions in Matter) software. The simulation and biological results indicate that ions did not penetrate the tissue of dry or hydrated seeds at all used ion energies. Therefore the entire energy was transferred to the treated tissue. Irradiated seeds were germinated vertically under dim light and roots growth was observed for two days after imbibition. The LD50 of the germination was about 2×1014 ions/cm2 and about 5×1014 ions/cm2 for imbibed and dry seeds, respectively. Since seedlings are most sensitive to gravity, the change in gravitropic behavior is a convenient means to assess radiation damage on physiological responses other than direct tissue

  3. Characterization and expression patterns of small RNAs in synthesized Brassica hexaploids.

    Science.gov (United States)

    Shen, Yanyue; Zhao, Qin; Zou, Jun; Wang, Wenliang; Gao, Yi; Meng, Jinling; Wang, Jianbo

    2014-06-01

    Polyploidy has played an important role in promoting plant evolution through genomic merging and doubling. We used high-throughput sequencing to compare miRNA expression profiles between Brassica hexaploid and its parents. A total of 613, 784 and 742 known miRNAs were identified in Brassica rapa, Brassica carinata, and Brassica hexaploid, respectively. We detected 618 miRNAs were differentially expressed (log(2)Ratio ≥ 1, P ≤ 0.05) between Brassica hexaploid and its parents, and 425 miRNAs were non-additively expressed in Brassica hexaploid, which suggest a trend of non-additive miRNA regulation following hybridization and polyploidization. Remarkably, majority of the non-additively expressed miRNAs in the Brassica hexaploid are repressed, and there was a bias toward repression of B. rapa miRNAs, which is consistent with the progenitor-biased gene repression in the synthetic allopolyploids. In addition, we identified 653 novel mature miRNAs in Brassica hexaploid and its parents. Finally, we found that almost all the non-additive accumulation of siRNA clusters exhibited a low-parent pattern in Brassica hexaploid. Non-additive small RNA regulation is involved in a range of biological pathways, probably providing a driving force for variation and adaptation in allopolyploids.

  4. Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity▿†

    Science.gov (United States)

    Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

    2011-01-01

    The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so

  5. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish potato famine pathogen, P. infestans.

    Directory of Open Access Journals (Sweden)

    Erica M Goss

    Full Text Available Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c.

  6. Germination of Phytophthora ramorum chlamydospores: a comparison of separation method and chlamydospore age

    Science.gov (United States)

    Justin P. Shaffer; Jennifer L. Parke

    2013-01-01

    Phytophthora ramorum characteristically produces large amounts of chlamydospores in vitro, but the role of these propagules in the disease cycle remains unclear. Germination is difficult to observe and quantify if chlamydospores are not free of mycelium, and the low frequency of germination commonly reported suggests that...

  7. Longevity of active Phytophthora ramorum in terminal tree hosts following the removal of primary sporulating hosts

    Science.gov (United States)

    Barnaby Wylder; Mick Biddle; Anna Harris; Joan Webber

    2017-01-01

    The Forestry Commission-managed forest estate located in Plym, Devon (southwest England) was one of the first locations in late summer 2009 to have stands of Larix kaempferi (Japanese larch) confirmed as infected with Phytophthora ramorum (EU1 lineage). The 398 ha forest had a high proportion (>30%) of

  8. The effect of salinity on the growth, sporulation and infection of Phytophthora ramorum

    Science.gov (United States)

    Phytophthora ramorum, a threat to Eastern U.S. forests, has been found in waterways outside the boundaries of infested ornamental nurseries. Very little is known about what factors are conducive to its survival and sporulation in water. This study examined the effect of salt on growth, sporulation,...

  9. Virulence, sporulation, and elicitin production in three clonal lineages of Phytophthora ramorum

    Science.gov (United States)

    Phytophthora ramorum populations are clonal and consist of three lineages. Recent studies have shown that the clonal lineages may have varying degrees of aggressiveness on some host species, such as Quercus rubra. In this study, we examined virulence, sporulation and elicitin production of five P. ...

  10. Temperature effects on the onset of sporulation by Phytophthora ramorum on rhododendron Cunningham’s White

    Science.gov (United States)

    The effect of temperature and moist period on the onset of sporangia production by Phytophthora ramorum on Rhododendron ‘Cunningham’s White’ was examined with misted detached leaves held in humid chambers. Following wound-inoculation with sporangia, leaves were preincubated at 20°C for either 24 or...

  11. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation

    Science.gov (United States)

    The acquisition of plant sterols, mediated via elicitins, is required for growth and sporulation of Phytophthora spp. In this paper, we looked at the interaction between elicitins, sterols, and tannins. When ground leaf tissue was added to growth media, P. ramorum growth and sporulation was greates...

  12. Sporulation capacity of Phytophthora ramorum on northern red oak and chestnut oak

    Science.gov (United States)

    Branches from six 2 to 3-year old northern red and chestnut oak seedlings were dip-inoculated with ca. 5,000 sporangia per milliliter of Phytophthora ramorum isolate Pr-6 and incubated at 100 percent relative humidity in dew chambers for 6 days. Three plants were then used to assess sporangia produ...

  13. Differences in virulence and sporulation of Phytophthora kernoviae isolates originating from two distinct geographical regions

    Science.gov (United States)

    Phytophthora kernoviae has only been isolated from the United Kingdom (U.K.) and New Zealand. To understand what differences may exist between isolates from these two distinct geographical regions, virulence studies on three host plants and sporulation on host leaves were conducted on select isolat...

  14. Infectivity and sporulation of Phytophthora ramorum on northern red oak and chestnut oak

    Science.gov (United States)

    Branches from northern red and chestnut oak seedlings were dip-inoculated with 5,000 sporangia per milliliter of Phytophthora ramorum and incubated at 100 percent relative humidity in dew chambers for 6 days. Three plants were then used to assess sporangia production, while the other three plants w...

  15. Assessment of potential economic and environmental impacts caused by Phytophthora ramorum in Europe

    Science.gov (United States)

    Hella Kehlenbeck

    2008-01-01

    Economic and environmental impacts of Phytophthora ramorum in Europe were evaluated within the European Union framework 6 project on ?Risk Analysis for P. ramorum a pathogen threat to Europe? (RAPRA). Impact assessment was conducted according to three different scenarios: 1. ?Nursery System? - describes losses occurring in...

  16. Relationship between field resistance to Phytophthora ramorum and constitutive phenolic chemistry of coast live oak

    Science.gov (United States)

    A.M. Nagle; B.A. McPherson; D.L. Wood; M. Garbelotto; A.O. Conrad; S. Opiyo; P. Bonello

    2012-01-01

    Sudden oak death, caused by Phytophthora ramorum, has resulted in high levels of coast live oak (Quercus agrifolia Nee (CLO) mortality. However, some CLO survive in areas with high disease pressure and may thus be resistant. We tested the hypothesis that such field resistant trees contain constitutively higher levels of...

  17. Attraction of ambrosia and bark beetles to coast live oaks infected by Phytophthora ramorum

    Science.gov (United States)

    Brice A. McPherson; Nadir Erbilgin; David L. Wood; Pavel Svihra; Andrew J. Storer; Richard B. Standiford

    2008-01-01

    Sudden oak death, caused by Phytophthora ramorum (Werres, de Cock & Man in?t Veld), has killed thousands of oaks (Quercus spp.) in coastal California forests since the mid-1990s. Bark and ambrosia beetles that normally colonize dead or severely weakened trees selectively tunnel into the bleeding cankers that are the first...

  18. Metabolite profiling to predict resistance to Phytophthora ramorum in natural populations of coast live oak

    Science.gov (United States)

    A. Conrad; B. Mcpherson; D. Wood; S. Opiyo; S. Mori; P. Bonello

    2013-01-01

    Sudden oak death, caused by the invasive oomycete pathogen Phytophthora ramorum, continues to shape the dynamics of coastal populations of oak (Quercus spp.) and tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh) in California and tanoak in southwestern Oregon. Over the...

  19. Impacts of Phytophthora ramorum on oaks and tanoaks in Marin County, California forests since 2000

    Science.gov (United States)

    Brice A. McPherson; David L. Wood; Maggi Kelly; Sylvia R. Mori; Pavel Svihra; Andrew J. Storer; Richard B. Standiford

    2010-01-01

    The forests of Marin County were among the first in coastal California to be affected by the Phytophthora ramorum epidemic. Although initially observed in 1994 in tanoaks (Lithocarpus densiflorus) and 1995 in coast live oaks (Quercus agrifolia), it is evident from studies of disease progression that the...

  20. Phytophthora ramorum in coast live oak: search for resistance and mechanisms.

    Science.gov (United States)

    B.A. McPherson; D.L. Wood; S.R. Mori; A. Conrad; P. Bonello

    2013-01-01

    Despite the presence of Phytophthora ramorum in northern and central California forests since at least 1994, asymptomatic coast live oaks (Quercus agrifolia Née) still remain in heavily infested stands. Coast live oak infection and mortality rates of 5 percent y-1 and 3 percent y-1, respectively, observed in long-term...

  1. The response of saprotrophic beetles to coast live oaks infected with Phytophthora ramorum

    Science.gov (United States)

    Brice A. McPherson; Nadir Ebilgin; David L. Wood; Pavel Svihra; Andrew J. Storer; Richard B. Standiford

    2006-01-01

    Saprotro phic ambrosia and bark beetles (Coleoptera: Scolytidae) tunnel into the bark overlying cankers caused by Phytophthora ramorum in coast live oaks, Quercus agrifolia. These insects are characteristically reported to colonize freshly dead or moribund trees (Furniss and Carolin, 1977). However, the initial attacks by these...

  2. Vegetation response following Phytophthora ramorum eradication treatments in southwest Oregon forests

    Science.gov (United States)

    Ellen Michaels Goheen; Everett Hansen; Alan Kanaskie; Wendy Sutton; Paul Reeser

    2008-01-01

    Sudden oak death, caused by Phytophthora ramorum, was identified in late July 2001 in forest stands in Curry County on the southwest Oregon coast where it was killing tanoak (Lithocarpus densiflorus) and infecting Pacific rhododendron (Rhododendron macrophyllum) and evergreen huckleberry (Vaccinium...

  3. Eradication of Phytophthora ramorum from Oregon forests: status after 6 years

    Science.gov (United States)

    Alan Kanaskie; Ellen Goheen; Nancy Osterbauer; Mike McWilliams; Everett Hansen; Wendy Sutton

    2008-01-01

    Sudden oak death (SOD), caused by Phytophthora ramorum, was first discovered in Oregon forests in July 2001. Since then an interagency team has been working with landowners to eradicate the pathogen by cutting and burning all infected and nearby host plants. During the first two years of the eradication effort, all host vegetation within 15 to 30 m...

  4. Four years experience with filtration systems in commercial nurseries for eliminating Phytophthora species from recirculation water

    Science.gov (United States)

    T. Ufer; M. Posner; H.-P. Wessels; S. Wagner; K. Kaminski; T. Brand; Werres S.

    2008-01-01

    In a four year project, three different filtration systems were tested under commercial nursery conditions to eliminate Phytophthora spp. from irrigation water. Five nurseries were involved in the project. Slow sand filtration systems were tested in three nurseries. In the fourth nursery, a filtration system with lava grains (Shieer® Bio filtration)...

  5. New Phytophthora populations: A shift from indirect to direct sporangial germination?

    NARCIS (Netherlands)

    Kessel, G.J.T.; Veloso, S.; Forch, M.G.; Latorse, M.P.

    2009-01-01

    Phytophthora infestans, the causal agent of potato- and tomato late blight, remains a serious threat for (commercial) potato and tomato production. In North Western Europe, frequent fungicide applications, mostly aimed to prevent infection, form the back bone of potato late blight control. Modern

  6. Innovation and dedication underpin management of sudden oak death (Phytophthora ramorum) in California and Oregon forests

    Science.gov (United States)

    Susan J. Frankel

    2017-01-01

    This special issue of Forest Phytophthoras serves as part of the proceedings from the Sixth Sudden Oak Death Science Symposium held June 21 -23, 2016 at Fort Mason Center in San Francisco, CA, USA. The symposium marked almost 16 years to the day that David Rizzo (UC Davis) and Matteo Garbelotto (UC Berkeley) identified the cause of sudden oak death to be a previously...

  7. Extended abstract on the potential for Phytophthora ramorum to infest finished compost

    Science.gov (United States)

    Steven Swain; Matteo Garbelotto

    2006-01-01

    The survival rate of Phytophthora ramorum was assessed when introduced at high rates into composts of varying provenance and curing time, produced by both "turned windrow" and "forced air static pile" techniques. Survival in some compost media was high and statistically indistinguishable from positive controls (P

  8. New technologies to detect and monitor Phytophthora ramorum in plant, soil, and water samples

    Science.gov (United States)

    Paul Russell; Nathan McOwen; Robert Bohannon

    2013-01-01

    The focus of our research efforts has been to develop methods to quickly identify plants, soil, and water samples infested with Phytophthora spp., and to rapidly confirm the findings using novel isothermal DNA technologies suitable for field use. These efforts have led to the development of a rapid Immunostrip® that reliably detects...

  9. Effects of environmental variables on the survival of Phytophthora ramorum in bay laurel leaves

    Science.gov (United States)

    M.V. DiLeo; R.M. Bostock; D.M. Rizzo

    2008-01-01

    Bay laurel (Umbellularia californica (Hook. & Arn.) Nutt.) is the primary reservoir host of Phytophthora ramorum Werres, De Cock & Man n?t Veld in coastal California woodlands. Non-lethal foliar lesions on bay laurel trees support the majority of pathogen sporulation during the winter et season and appear to provide the...

  10. Survival and chlamydospore production of Phytophthora ramorum in California bay laurel leaves

    Science.gov (United States)

    E. Fichtner; D. Rizzo; S. Lynch; D. Rizzo; G. Buckles; J. Parke

    2009-01-01

    Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. The pathogen survives the dry summers in a proportion of attached bay leaves, but the propagules responsible for survival are...

  11. Host phenology and leaf effects on susceptibility of California bay laurel to Phytophthora ramorum

    Science.gov (United States)

    Steven F. Johnston; Michael F. Cohen; Tamas Torok; Ross K. Meentemeyer; Nathan E. Rank

    2016-01-01

    Spread of the plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death, is driven by a few competent hosts that support spore production from foliar lesions. The relationship between traits of a principal foliar host, California bay laurel (Umbellularia californica), and susceptibility to

  12. Pathways of spread of Phytophthora ramorum in a simulated nursery setting: an update

    Science.gov (United States)

    Kurt Heungens; Bjorn Gehesqui& egrave; re; Kris Van Poucke; Annelies Vercauteren; Martine. Maes

    2013-01-01

    European phytosanitary measures as applied to nurseries require that potential host plants within a radius of 2 m of a Phytophthora ramorum-infected plant must be destroyed and that remaining host plants within a radius of 10 m cannot be traded until they are inspected and found to be pest free at further specific inspections. Despite the wide...

  13. Ethanol attracts scolytid beetles to Phytophthora ramorum cankers on coast live oak

    Science.gov (United States)

    Rick G. Kelsey; Maia M. Beh; David C. Shaw; Daniel K. Manter

    2013-01-01

    Ethanol in sapwood was analyzed along vertical transects, through small spot cankers and larger basal cankers, of Phytophthora ramorum-infected stems of Quercus agrifolia at three sites in California. Trees with large basal cankers, known to attract scolytid beetles, had a 4.3 times higher ethanol level than trees with spot cankers...

  14. Ethanol attracts scolytid beetles to Phytophthora ramorum cankers on coast live oak [Abstract

    Science.gov (United States)

    Rick G. Kelsey; Maia Beh; Dave Shaw; Daniel K. Manter

    2013-01-01

    Successful infection of coast live oak (Quercus agrifolia Née) stems by Phytophthora ramorum results in the formation of a canker visible initially at the bark surface by the release of a dark red to black colored exudate referred to as "bleeding." Bark and ambrosia beetles are often attracted to diseased trees within...

  15. Multiplex SSR analysis of Phytophthora infestans in different countries and the importance for potato breeding

    NARCIS (Netherlands)

    Li, Y.

    2012-01-01

    Potato is the most important non-cereal crop in the world. Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease of potato. In the mid-19th century, P. infestans attacked the European potato fields and this resulted in a widespread famine in Ireland

  16. Use of microsatellite markers derived from whole genome sequence data for identifying polymorphism in Phytophthora ramorum

    Science.gov (United States)

    Kelly Ivors; Matteo Garbelotto; Ineke De Vries; Peter Bonants

    2006-01-01

    Investigating the population genetics of Phytophthora ramorum, the causal agent of sudden oak death (SOD), is critical to understanding the biology and epidemiology of this important phytopathogen. Raw sequence data (445,000 reads) of P. ramorum was provided by the Joint Genome Institute. Our objective was to develop and utilize...

  17. Phytophthora ramorum and sudden oak death in California: III. preliminary studies in pathogen genetics

    Science.gov (United States)

    Matteo Garbelotto; David M. Rizzo; Katie Hayden; Monica Meija-Chang; Jennifer M. Davidson; Steven Tjosvold

    2002-01-01

    Sudden oak death (SOD) has been shown to be caused by a new species of Phytophthora, P. ramorum. A basic understanding of the genetics of P. ramorum is critical to any management strategy. We have initiated a number of studies to examine species concepts, population biology and mating behavior of the pathogen....

  18. Collateral damage: fire and Phytophthora ramorum interact to increase mortality in coast redwood

    Science.gov (United States)

    Margaret R. Metz; J. Morgan Varner; Kerri M. Frangioso; Ross K. Meentemeyer; David M. Rizzo

    2013-01-01

    Invading species can alter ecosystems by impacting the frequency, severity, and consequences of endemic disturbance regimes (Mack and D'Antonio 1998). Phytophthora ramorum, the causal agent of the emergent disease sudden oak death (SOD), is an invasive pathogen causing widespread tree mortality in coastal forests of California and Oregon. In...

  19. Susceptibility to Phytophthora ramorum in California bay laurel, a key foliar host of sudden oak death

    Science.gov (United States)

    Brian L. Anacker; Nathan E. Rank; Daniel Hüberli; Matteo Garbelotto; Sarah Gordon; Rich Whitkus; Tami Harnik; Matthew Meshriy; Lori Miles; Ross K. Meentemeyer

    2008-01-01

    Sudden oak death, caused by the water mold Phytophthora ramorum, is a plant disease responsible for the death of hundreds of thousands of oak and tanoak trees. Some foliar hosts play a major role in the epidemiology of this disease. Upon infection by P. ramorum, these foliar hosts express non-fatal leaf lesions from which large...

  20. Genetic structure of the population of Phytophthora infestans attacking Solanum ochranthum in the highlands of Ecuador

    NARCIS (Netherlands)

    Chacón, M.G.; Adler, N.E.; Jarrin, F.; Flier, W.G.; Gessler, C.; Forbes, G.A.

    2006-01-01

    Thirty-nine isolates of Phytophthora infestans were collected from the wild host Solanum ochranthum in the highland tropics of Ecuador and characterized with a set of phenotypic and molecular markers (mating type, metalaxyl sensitivity, the allozyme loci Gpi, and Pep, mitochondrial DNA haplotype,

  1. Tracking populations and new infections of Phytophthora ramorum in southern Oregon forests

    Science.gov (United States)

    Jennifer Britt; Simone Prospero; Niklaus Grünwald; Alan Kanaskie; Everett Hansen

    2010-01-01

    Since the discovery of Phytophthora ramorum in southern Oregon forests in 2001, newly infested areas are located each year. We tracked the spread and dispersal using DNA fingerprinting. While among site genetic variance was low, we did find changes in genotype presence and frequency at the site level. These genotypic differences allowed us to...

  2. Anaerobic soil disinfestation reduces survival and infectivity of Phytophthora nicotianae chlamydospores in pepper

    Science.gov (United States)

    Phytophthora nicotianae is the principal causal agent of root and crown rot disease of pepper plants in Extremadura (western Spain), a spring-summer crop in this region. Preplant soil treatment by anaerobic soil disinfestation (ASD) may effectively control plant pathogens in many crop production sys...

  3. Molecular characterization of natural hybrids of Phytophthora nicotianae and P. cactorum

    NARCIS (Netherlands)

    Bonants, P.J.M.; Hagenaar-de Weerdt, M.; Man in 't Veld, W.A.; Baayen, R.P.

    2000-01-01

    Hybrid isolates of Phytophthora nicotianae x P. cactorum from five different hosts (Cyclamen, Lavandula, Lewisia, Primula, and Spathiphyllum spp.) were identified by their atypical morphology and their well-defined heterozygous isozyme patterns. The hybrid nature of these isolates was tested by

  4. Clonal expansion of the Belgian Phytophthora ramorum populations based on new microsatellite markers

    Science.gov (United States)

    A. Vercauteren; I. De Dobbelaere; N. J. Grünwald; P. Bonants; E. Van Bockstaele; M. Maes; K. Heungens

    2010-01-01

    Co-existence of both mating types A1 and A2 within the EU1 lineage of Phytophthora ramorum has only been observed in Belgium, which begs the question whether sexual reproduction is occurring. A collection of 411 Belgian P. ramorum isolates was established during a 7-year survey. Our main objectives were genetic characterization of this population to test for sexual...

  5. Phytophthora effector targets a novel component of small RNA pathway in plants to promote infection.

    Science.gov (United States)

    Qiao, Yongli; Shi, Jinxia; Zhai, Yi; Hou, Yingnan; Ma, Wenbo

    2015-05-05

    A broad range of parasites rely on the functions of effector proteins to subvert host immune response and facilitate disease development. The notorious Phytophthora pathogens evolved effectors with RNA silencing suppression activity to promote infection in plant hosts. Here we report that the Phytophthora Suppressor of RNA Silencing 1 (PSR1) can bind to an evolutionarily conserved nuclear protein containing the aspartate-glutamate-alanine-histidine-box RNA helicase domain in plants. This protein, designated PSR1-Interacting Protein 1 (PINP1), regulates the accumulation of both microRNAs and endogenous small interfering RNAs in Arabidopsis. A null mutation of PINP1 causes embryonic lethality, and silencing of PINP1 leads to developmental defects and hypersusceptibility to Phytophthora infection. These phenotypes are reminiscent of transgenic plants expressing PSR1, supporting PINP1 as a direct virulence target of PSR1. We further demonstrate that the localization of the Dicer-like 1 protein complex is impaired in the nucleus of PINP1-silenced or PSR1-expressing cells, indicating that PINP1 may facilitate small RNA processing by affecting the assembly of dicing complexes. A similar function of PINP1 homologous genes in development and immunity was also observed in Nicotiana benthamiana. These findings highlight PINP1 as a previously unidentified component of RNA silencing that regulates distinct classes of small RNAs in plants. Importantly, Phytophthora has evolved effectors to target PINP1 in order to promote infection.

  6. Draft genome sequences of seven isolates of Phytophthora ramorum EU2 from Northern Ireland

    Directory of Open Access Journals (Sweden)

    Lourdes de la Mata Saez

    2015-12-01

    Full Text Available Here we present draft-quality genome sequence assemblies for the oomycete Phytophthora ramorum genetic lineage EU2. We sequenced genomes of seven isolates collected in Northern Ireland between 2010 and 2012. Multiple genome sequences from P. ramorum EU2 will be valuable for identifying genetic variation within the clonal lineage that can be useful for tracking its spread.

  7. Efficacy of management tools for control of Phytophthora plurivora leaf spot of Rhododendron, 2014

    Science.gov (United States)

    This study was conducted as part of the IR-4 Ornamental Horticulture program to evaluate fungicides and biopesticides for management of leaf spot of Rhododendron caused by Phytophthora plurivora. The experiment was conducted by treating two-year old Rhododendron plants with fungicides on September 2...

  8. The Phytophthora species assemblage and diversity in riparian alder ecosystems of western Oregon, USA.

    Science.gov (United States)

    Sims, Laura Lee; Sutton, Wendy; Reeser, Paul; Hansen, Everett M

    2015-01-01

    Phytophthora species were systematically sampled, isolated, identified and compared for presence in streams, soil and roots of alder (Alnus species) dominated riparian ecosystems in western Oregon. We describe the species assemblage and evaluate Phytophthora diversity associated with alder. We recovered 1250 isolates of 20 Phytophthora species. Only three species were recovered from all substrates (streams, soil, alder roots): P. gonapodyides, the informally described "P. taxon Pgchlamydo", and P. siskiyouensis. P. alni ssp. uniformis along with five other species not previously recovered in Oregon forests are included in the assemblage: P.citricola s.l., P. gregata, P. gallica, P. nicotianae and P. parsiana. Phytophthora species diversity was greatest in downstream riparian locations. There was no significant difference in species diversity comparing soil and unwashed roots (the rhizosphere) to stream water. There was a difference between the predominating species from the rhizosphere compared to stream water. The most numerous species was the informally described "P. taxon Oaksoil", which was mainly recovered from, and most predominant in, stream water. The most common species from riparian forest soils and alder root systems was P. gonapodyides. © 2015 by The Mycological Society of America.

  9. Comparing methods for inducing root rot of Rhododendron with Phytophthora cinnamomi and P. plurivora

    Science.gov (United States)

    Root rot, caused by Phytophthora cinnamomi and P. plurivora in containerized Rhododendron, can cause significant losses in the nursery industry. Studies commonly use a 48 h flooding event to stimulate root infection. While flooding rarely occurs in container nurseries, plants may sit in a shallow pu...

  10. Effects of temperature on germination of sporangia, infection and protein secretion by Phytophthora kernoviae

    Science.gov (United States)

    Phytophthora kernoviae has been reported to cause bleeding stem lesions and foliar necrosis on a wide range of species, with little knowledge of the optimal conditions for infection. Detached Rhododendron ponticum leaves were inoculated with six different isolates of P. kernoviae sporangia and set ...

  11. Rapid Determination of Phytophthora infestans sporangia Using a Surface Plasmon Resonance Immunosensor

    DEFF Research Database (Denmark)

    Skottrup, Peter; Nicolaisen, Mogens; Justesen, Annemarie Fejer

    2007-01-01

    Phytophthora infestans is the cause of late blight disease in potato and is an economically important pathogen worldwide. Early disease detection is important to implement disease control measures. In this study a surface plasmon resonance (SPR) immunosensor for detection of P. infestans sporangia...

  12. Whole genome sequences of the raspberry and strawberry pathogens Phytophthora rubi and P. fragariae

    Science.gov (United States)

    Phytophthora rubi and P. fragariae are two closely related oomycete plant pathogens that exhibit strong morphological and physiological similarities, but are specialized to infect different hosts of economic importance, namely raspberry and strawberry. Here, we report the draft genome sequences of t...

  13. Nonchemical, cultural management strategies to suppress phytophthora root rot in northern highbush blueberry

    Science.gov (United States)

    Phytophthora cinnamomi causes root rot of highbush blueberry and decreases plant growth, yield, and profitability for growers. Fungicides can suppress root rot, but cannot be used in certified organic production systems and fungicide resistance may develop. Alternative, non-chemical, cultural manag...

  14. Efficient Genome Editing in the Oomycete Phytophthora sojae Using CRISPR/Cas9.

    Science.gov (United States)

    Fang, Yufeng; Cui, Linkai; Gu, Biao; Arredondo, Felipe; Tyler, Brett M

    2017-02-06

    Phytophthora is a filamentous fungus-like microorganism, but belongs to the oomycetes, in the kingdom Stramenopila. Phytophthora species are notorious as plant destroyers, causing multibillion-dollar damage to agriculture and natural ecosystems worldwide annually. For a long time, genome editing has been unattainable in oomycetes, because of their extremely low rate of homologous recombination. The recent implementation of the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system in the soybean pathogen Phytophthora sojae, an experimental model for oomycetes, has opened up a powerful new research capability for the oomycete community. Here, we describe a detailed protocol for CRISPR/Cas9-mediated genome editing in P. sojae, including single guide RNA (sgRNA) design and construction, efficient gene replacement, and mutant-screening strategies. This protocol should be generally applicable for most culturable oomycetes. We also describe an optimized transformation method that is useful for other Phytophthora spp. including P. capsici and P. parasitica. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  15. Population structure and genetic diversity of Phytophthora nicotianae from tobacco in Georgia

    Science.gov (United States)

    Black shank caused by Phytophthora nicotianae occurs worldwide and is responsible for significant yield loss in tobacco production in Georgia. Management of the disease has primarily relied on utilization of tobacco cultivars with resistance to race 0 of the pathogen and application of the fungicide...

  16. Interaction of Trichoderma asperellum with Phytophthora ramorum inoculum soil populations and enzyme secretion

    Science.gov (United States)

    Supriya Sharma; Wolfgang Schweigkofler; Karen Suslow; Timothy L. Widmer

    2017-01-01

    There is a continuing desire to investigate the potential of biological control to manage the spread of Phytophthora ramorum. A specific isolate of Trichoderma asperellum has been demonstrated to be effective in reducing P. ramorum soil populations to non-detectable levels. This study was conducted...

  17. Marine Phytophthora species can hamper conservation and restoration of vegetated coastal ecosystems

    NARCIS (Netherlands)

    Govers, Laura L.; Man in 't Veld, Willem A.; Meffert, Johan P.; Bouma, Tjeerd J.; van Rijswick, Patricia C. J.; Heusinkveld, Jannes H. T.; Orth, Robert J.; van Katwijk, Marieke M.; van der Heide, Tjisse

    2016-01-01

    Phytophthora species are potent pathogens that can devastate terrestrial plants, causing billions of dollars of damage yearly to agricultural crops and harming fragile ecosystems worldwide. Yet, virtually nothing is known about the distribution and pathogenicity of their marine relatives. This is

  18. Evaluation of watermelon varieties for tolerance to powdery mildew and Phytophthora fruit rot, 2014

    Science.gov (United States)

    This experiment was conducted at the U.S. Vegetable Laboratory farm in Charleston, SC. The soil was Yonges loamy fine sand. This study was undertaken to determine the performance of seeded and seedless commercial watermelon varieties for tolerance to powdery mildew (PM) and Phytophthora fruit rot as...

  19. Isolation and Pathogenicity of Phytophthora Species from Poplar Plantations in Serbia

    Directory of Open Access Journals (Sweden)

    Ivan Milenković

    2018-06-01

    Full Text Available During a survey in three declining and three healthy poplar plantations in Serbia, six different Phytophthora species were obtained. Phytophthora plurivora was the most common, followed by P. pini, P. polonica, P. lacustris, P. cactorum, and P. gonapodyides. Pathogenicity of all isolated species to four-month and one-year-old cuttings of Populus hybrid clones I-214 and Pánnonia, respectively, was tested using both a soil infestation and stem inoculation test. Isolates of P. polonica, P. × cambivora, P. cryptogea, and P. × serendipita from other host plants were included as a comparison. In the soil infestation test, the most aggressive species to clone I-214 were P. plurivora, P. × serendipita, and P. pini. On clone Pánnonia, P. gonapodyides and P. pini were the most aggressive, both causing 100% mortality, followed by P. cactorum, P. × cambivora, and P. polonica. In the underbark inoculation test, the susceptibility of both poplar clones to the different Phytophthora species was largely similar, as in the soil infestation test, with the exception of P. polonica, which proved to be only weakly pathogenic to poplar bark. The most aggressive species to clone I-214 was P. pini, while on clone Pánnonia, the longest lesions and highest disease incidence were caused by P. gonapodyides. Phytophthora cactorum and P. plurivora were pathogenic to both clones, whereas P. × cambivora showed only weak pathogenicity. The implications of these findings and possible pathways of dispersion of the pathogens are discussed.

  20. Marine Phytophthora species can hamper conservation and restoration of vegetated coastal ecosystems.

    Science.gov (United States)

    Govers, Laura L; Man In 't Veld, Willem A; Meffert, Johan P; Bouma, Tjeerd J; van Rijswick, Patricia C J; Heusinkveld, Jannes H T; Orth, Robert J; van Katwijk, Marieke M; van der Heide, Tjisse

    2016-08-31

    Phytophthora species are potent pathogens that can devastate terrestrial plants, causing billions of dollars of damage yearly to agricultural crops and harming fragile ecosystems worldwide. Yet, virtually nothing is known about the distribution and pathogenicity of their marine relatives. This is surprising, as marine plants form vital habitats in coastal zones worldwide (i.e. mangrove forests, salt marshes, seagrass beds), and disease may be an important bottleneck for the conservation and restoration of these rapidly declining ecosystems. We are the first to report on widespread infection of Phytophthora and Halophytophthora species on a common seagrass species, Zostera marina (eelgrass), across the northern Atlantic and Mediterranean. In addition, we tested the effects of Halophytophthora sp. Zostera and Phytophthora gemini on Z. marina seed germination in a full-factorial laboratory experiment under various environmental conditions. Results suggest that Phytophthora species are widespread as we found these oomycetes in eelgrass beds in six countries across the North Atlantic and Mediterranean. Infection by Halophytophthora sp. Zostera, P. gemini, or both, strongly affected sexual reproduction by reducing seed germination sixfold. Our findings have important implications for seagrass ecology, because these putative pathogens probably negatively affect ecosystem functioning, as well as current restoration and conservation efforts. © 2016 The Author(s).

  1. Dual RNA-seq of the plant pathogen phytophthora ramorum and its tanoak host

    Science.gov (United States)

    Katherine J. Hayden; Matteo Garbelotto; Brian J. Knaus; Richard C. Cronn; Hardeep Rai; Jessica W. Wright

    2014-01-01

    Emergent diseases are an ever-increasing threat to forests and forest ecosystems and necessitate the development of research tools for species that often may have few preexisting resources. We sequenced the mRNA expressed by the sudden oak death pathogen Phytophthora ramorum and its most susceptible forest host, tanoak, within the same tissue at two time points after...

  2. Susceptibility to Phytophthora ramorum and inoculum production potential of some common eastern forest understory plant species

    Science.gov (United States)

    Paul W. Tooley; Marsha Browning

    2009-01-01

    Twenty-five plant species (21 genera, 14 families), which comprise a portion of the understory in forests of the Eastern United States, were evaluated for susceptibility to infection by Phytophthora ramorum. The degree to which P. ramorum is able to form sporangia and chlamydospores was also assessed on...

  3. Evaluation of molecular markers for Phytophthora ramorum detection and identification using a standardized library of isolates

    Science.gov (United States)

    F.N. Martin; M. Coffey; R. Hamelin; P. Tooley; M. Garbelotto; K. Hughes; T. Kubisiak

    2008-01-01

    A number of molecular diagnostic procedures for detection of Phytophthora ramorum have been reported in the literature. In an effort to evaluate the specificity of 10 of these techniques a standardized DNA library for 317 isolates was assembled that included 60 described species as well as 22 taxonomically unclassified isolates. These were sent blind...

  4. Understanding the role of L-type lectin receptor kinases in Phytophthora resistance

    NARCIS (Netherlands)

    Wang, Y.

    2014-01-01

    Abstract

    Phytophthora pathogens are notorious for causing severe damage to many agriculturally and ornamentally important plants. Effective plant resistance depends largely on the capacity to perceive pathogens and to activate rapid defence. Cytoplasmic resistance

  5. Effectiveness of fungicides in protecting Douglas-fir shoots from infection by Phytophthora ramorum

    Science.gov (United States)

    G.A. Chastagner; E.M. Hansen; K.L. Riley; W. Sutton

    2006-01-01

    The effectiveness of 20 systemic and contact fungicides in protecting Douglas-fir seedlings from infection by Phytophthora ramorum was determined. Some systemic products were applied about a week prior to bud break, while most treatments were applied just after bud break. In addition to the fungicides, two surfactants were included in the post-bud...

  6. Sudden Oak Death, Phytophthora ramorum: A Persistent Threat to Oaks and Other Tree Species

    Science.gov (United States)

    S.J. Frankel; K.M. Palmieri

    2014-01-01

    This paper reviews the status and management of sudden oak death and “sudden larch death” in the urban and wildland forests of California, Oregon, and the UK. The causal pathogen, Phytophthora ramorum, was discovered in all three locations over a decade ago; however, efforts to contain and eliminate infestations have been unsuccessful. These less...

  7. Sudden oak death and Phytophthora ramorum: a summary of the literature

    Science.gov (United States)

    John T. Kliejunas

    2010-01-01

    Sudden oak death and Phytophthora ramorum, both first recognized about a decade ago, have been the subject of hundreds of scientific and popular press articles. This document presents a comprehensive, concise summary of sudden oak death and P. ramorum research findings and management activities. Topics covered include...

  8. Population structure of Phytophthora infestans in the Toluca Valley region of Central Mexico

    NARCIS (Netherlands)

    Grünwald, N.J.; Flier, W.G.; Sturbaum, A.K.; Garay-Serrano, E.; Bosch, van den G.B.M.; Smart, C.D.; Matuszak, J.M.; Turkensteen, L.J.; Fry, W.E.

    2001-01-01

    We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and

  9. Forecasting oak decline caused by Phytophthora cinnamomi in Andalusia: Identification of priority areas for intervention

    NARCIS (Netherlands)

    Duque Lazo, Joaquin; Navarro-Cerrillo, Rafael Maria; Van Gils, Hein; Groen, T.A.

    2018-01-01

    Since the mid-20th century, trees in the Andalusian oak dehesa and forests have exhibited stress that often ends in the death of the tree. These events have been associated with Phytophthora cinnamomi, a soil-borne root pathogen, which causes root rot, bark cankers, decay and mortality – known as

  10. Genes for and molecular markers linked with resistance to Phytophthora fragariae in strawberry

    NARCIS (Netherlands)

    Weg, van de W.E.; Henken, B.; Haymes, K.M.; Nijs, den A.P.M.

    1998-01-01

    A gene-for-gene model is presented which explains interactions between cultivars of strawberry and races of Phytophthora fragariae var. fragariae, the causal agent of red core (red stele) root rot. The model allows the constitution of a universal differential set of strawberry genotypes and the

  11. Methods for screening Port-Orford-cedar for resistance to Phytophthora lateralis

    Science.gov (United States)

    Everett M. Hansen; Paul Reeser; Wendy Sutton; Richard A. Sniezko

    2012-01-01

    Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murray) Parl.) (POC) is an economically and ecologically valuable tree in the forests of southwest Oregon and northern California and in the horticultural trade worldwide. Phytophthora lateralis, the aggressive, invasive cause of POC root disease, was introduced to the native...

  12. Large subclonal variation in Phytophthora infestans populations associated with Ecuadorian potato landraces

    NARCIS (Netherlands)

    Delgado, R.A.; Monteros-Altamiro, A.R.; Li, Y.; Visser, R.G.F.; Lee, van der T.A.J.; Vosman, B.

    2013-01-01

    The population of Phytophthora infestans on potato landraces in three provinces (Carchi, Chimborazo and Loja) of Ecuador was analysed. All isolates (n = 66) were of the A1 mating type. Simple sequence repeats (SSR) were used to assess the genetic diversity of the isolates. The P. infestans isolates

  13. The epidemiology of Phytophthora ramorum and P. kernoviae at two historic gardens in Scotland

    Science.gov (United States)

    M. Elliot; T.R. Meagher; C. Harris; K. Searle; B.V. Purse; A. Schlenzig

    2013-01-01

    This study looked at the factors that facilitated the spread of Phytophthora ramorum andP. kernoviae at two locations in the west of Scotland. Spore traps, river baiting, bait plants, and soil sampling were used to both confirm the presence of, and measure the amount of, inoculum in the environment in order...

  14. Genetic epidemiology of the Sudden Oak Death pathogen Phytophthora ramorum in California

    Science.gov (United States)

    S. Mascheretti; P.J.P. Croucher; M. Kozanitas; L. Baker; M. Garbelotto

    2009-01-01

    A total of 669 isolates of Phytophthora ramorum, the pathogen responsible for Sudden Oak Death, were collected from 34 Californian forests and from the ornamental plant-trade. Seven microsatellite markers revealed 82 multilocus genotypes (MGs) of which only three were abundant (>10%). Iteratively collapsing based upon minimum ΦST, yielded five meta-samples and five...

  15. Detection of Phytophthora ramorum at retail nurseries in the southeastern United States

    Science.gov (United States)

    Steven N. Jeffers; Jaesoon Hwang; Yeshi A. Wamishe; Steven W. Oak

    2010-01-01

    Many nursery plants are known to be hosts of Phytophthora ramorum or to be associated with this pathogen. These plants can be infected or merely infested by P. ramorum and with or without symptoms. The pathogen has been detected most frequently on container-grown nursery plants, and occasionally has been found in the container...

  16. PIXE studies of changes in host mineral compositions of plants due to Phytophthora Cinnamomi

    International Nuclear Information System (INIS)

    Papper, C.S.; Chaudhri, M.A.

    1978-01-01

    In order to study the effect of the disease due to Phytophthora Cinnamomi on the vegetation in Wilson's Promontory, the mineral compositions of tolerant and susceptible plants in both healthy and diseased areas have been compared, using proton-induced x-ray emission analysis

  17. First results with a lab-on-a-chip system for a fast Phytophthora diagnosis.

    Science.gov (United States)

    Sonja Horatzek; Stephan König; Stefan Wagner; Sabine Werres; Lydia Schwenkbier; Karina Weber; Jörg. Weber

    2013-01-01

    For Phytophthora spp. that are quarantine or regulated organisms, highly specific and sensitive diagnostic tools are recommended for surveys and monitoring. Furthermore, these diagnostic techniques should give results within a short time and should be not be too expensive. The techniques currently used for routine diagnosis of ...

  18. Activity of some aminoglycoside antibiotics against true fungi, Phytophthora and Pythium species.

    Science.gov (United States)

    Lee, H B; Kim, Y; Kim, J C; Choi, G J; Park, S-H; Kim, C-J; Jung, H S

    2005-01-01

    To investigate the in vitro antifungal and antioomycete activities of some aminoglycosides against true fungi and Phytophthora and Pythium species and to evaluate the potential of the antibiotics against Phytophthora late blight on plants. Antifungal and antioomycete activities of aminoglycoside antibiotics (neomycin, paromomycin, ribostamycin and streptomycin) and a paromomycin-producing strain (Streptomyces sp. AMG-P1) against Phytophthora and Pythium species and 10 common fungi were measured in potato dextrose broth (PDB) and on seedlings in pots. Paromomycin was the most active against Phytophthora and Pythium species with a minimal inhibitory concentration of 1-10 microg ml(-1) in PDB, but displayed low to moderate activities towards other common fungi at the same concentration. Paromomycin also showed potent in vivo activity against red pepper and tomato late blight diseases with 80 and 99% control value, respectively, at 100 microg ml(-1). In addition, culture broth of Streptomyces sp. AMG-P1 as a paromomycin producer exhibited high in vivo activity against late blight at 500 microg freeze-dried weight per millilitre. Among tested aminoglycoside antibiotics, paromomycin was the most active against oomycetes both in vitro and in vivo. Data from this study show that aminoglycoside antibiotics have in vitro and in vivo activities against oomycetes, suggesting that Streptomyces sp. AMG-P1 may be used as a biocontrol agent against oomycete diseases.

  19. Recommended industry best management practices for the prevention of Phytophthora ramorum introduction in nursery operations

    Science.gov (United States)

    Karen Suslow

    2008-01-01

    The following industry recommended best management practices (BMPs), designed for growers and/or interstate shippers of host and associated host plants of Phytophthora ramorum, consists of biosecurity guidelines created by and for nursery growers in order to reduce the risks associated with P. ramorum. The control of P....

  20. Chemical control of Phytophthora ramorum causing foliar disease in hardy nursery stock in the United Kingdom

    Science.gov (United States)

    Judith Turner; Philip Jennings; Sam McDonough; Debbie Liddell; Jackie Stonehouse

    2006-01-01

    A range of fungicides have been tested for activity against P. ramorum using both in vitro and in vivo tests. All fungicides had proven activity against Phytophthora species and either had full approval for use on hardy ornamental nursery stock in the United Kingdom, or could be used under the Revised Long Term Arrangements for Extension of Use (2002...

  1. Natural outbreaks of Phytophthora ramorum in the U.K.—current status and monitoring update

    Science.gov (United States)

    Judith Turner; Philip Jennings; Gilli Humphries; Steve Parker; Sam McDonough; Jackie Stonehouse; David Lockley; David Slawson

    2008-01-01

    To date (February 2007) there have been 160 outbreaks of Phytophthora ramorum in gardens or woodlands in the U.K. Current EU policy requires that appropriate measures be taken to contain P. ramorum in such situations. In the U.K., the measures have either been aimed at eradication, through destruction of infected plants, or at...

  2. Seasonal symptom expression, laboratory detection success, and sporulation potential of Phytophthora ramorum on rhododendron and camellia

    Science.gov (United States)

    Steve A. Tjosvold; David L. Chambers; Cheryl L. Blomquist

    2008-01-01

    Camellias and rhododendrons are important nursery and landscape plants and are known to be highly susceptible hosts of the quarantined plant pathogen, Phytophthora ramorum Werres, de Cock & Man In?t Veld. Nursery inspection can not always occur during optimal conditions for the disease and its detection. The goals of this research were to (1)...

  3. Evaluation of fungicide rotations for management of Phytophthora fruit rot of watermelon, 2015

    Science.gov (United States)

    The experiment was conducted at the U.S. Vegetable Laboratory farm in Charleston, SC. The soil was Yonges loamy fine sand. For the past 6 years, the field has been infested with Phytophthora capsici. The experimental design was a randomized complete block with four replications. Five-week-old seedli...

  4. Phytophthora ramorum detections in Canada: Evidence for migration within North America and from Europe

    Science.gov (United States)

    E.M. Goss; M. Larsen; A. Vercauteren; S. Werres; K. Heungens; N.J. Grünwald

    2011-01-01

    Phytophthora ramorum, the cause of sudden oak death on oak and ramorum blight on woody ornamentals, has been reported in ornamental nurseries on the West Coast of North America from British Columbia to California. Long-distance migration of P. ramorum has occurred via the nursery trade, and shipments of host plants are known to...

  5. A Rapid Diagnostic Test to Distinguish Between American and European Populations of Phytophthora ramorum

    NARCIS (Netherlands)

    Kroon, L.P.N.M.; Verstappen, E.C.P.; Kox, L.F.F.; Flier, W.G.; Bonants, P.J.M.

    2004-01-01

    A new devastating disease in the United States, commonly known as Sudden Oak Death, is caused by Phytophthora ramorum. This pathogen, which previously was described attacking species of Rhododendron and Viburnum in Germany and the Netherlands, has established itself in forests on the central coast

  6. The Effect of Low Oxygen Stress on Phytophthora cinnamomi Infection and Disease of Cork Oak Roots

    Science.gov (United States)

    Karel A. Jacobs; James D. MacDonald; Alison M. Berry; Laurence R. Costello

    1997-01-01

    The incidence and severity of Phytophthora cinnamomi Rands root disease was quantified in cork oak (Quercus suber L.) roots subjected to low oxygen (hypoxia) stress. Seedling root tips were inoculated with mycelial plugs of the fungus and incubated in ≤1, 3-4, or 21 percent oxygen for 5 days. Ninety-four percent of roots...

  7. Survival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates

    Science.gov (United States)

    A. Vercauteren; M. Riedel; M. Maes; S. Werres; K. Heungens

    2013-01-01

    This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a...

  8. The phytophthora genome initiative database: informatics and analysis for distributed pathogenomic research.

    Science.gov (United States)

    Waugh, M; Hraber, P; Weller, J; Wu, Y; Chen, G; Inman, J; Kiphart, D; Sobral, B

    2000-01-01

    The Phytophthora Genome Initiative (PGI) is a distributed collaboration to study the genome and evolution of a particularly destructive group of plant pathogenic oomycete, with the goal of understanding the mechanisms of infection and resistance. NCGR provides informatics support for the collaboration as well as a centralized data repository. In the pilot phase of the project, several investigators prepared Phytophthora infestans and Phytophthora sojae EST and Phytophthora sojae BAC libraries and sent them to another laboratory for sequencing. Data from sequencing reactions were transferred to NCGR for analysis and curation. An analysis pipeline transforms raw data by performing simple analyses (i.e., vector removal and similarity searching) that are stored and can be retrieved by investigators using a web browser. Here we describe the database and access tools, provide an overview of the data therein and outline future plans. This resource has provided a unique opportunity for the distributed, collaborative study of a genus from which relatively little sequence data are available. Results may lead to insight into how better to control these pathogens. The homepage of PGI can be accessed at http:www.ncgr.org/pgi, with database access through the database access hyperlink.

  9. Genome sequences of Phytophthora enable translational plant disease management and accelerate research

    Science.gov (United States)

    Niklaus J. Grünwald

    2012-01-01

    Whole and partial genome sequences are becoming available at an ever-increasing pace. For many plant pathogen systems, we are moving into the era of genome resequencing. The first Phytophthora genomes, P. ramorum and P. sojae, became available in 2004, followed shortly by P. infestans...

  10. The effects of Phytophthora ramorum infection on hydraulic conductivity and tylosis formation in tanoak sapwood

    Science.gov (United States)

    Bradley R. Collins; Jennifer L. Parke; Barb Lachenbruch; Everett M. Hansen

    2009-01-01

    Tanoak (Lithocarpus densiflorus (Hook. and Arn.) Rehder) is highly susceptible to sudden oak death, a disease caused by the oomycete Phytophthora ramorum Werres, De Cock & Man in’t Veld. Symptoms include a dying crown, bleeding cankers, and, eventually, death of infected trees. The cause of mortality is not well understood, but recent research indicates that...

  11. Application of rapid onsite PCR (TaqMan) for Phytophthora ramorum under U.S. conditions

    Science.gov (United States)

    Kelvin Hughes; Jenny Tomlinson; Neil Boonham; Kelly Ivors; Matteo Garbelotto; Ian Barker

    2006-01-01

    Currently, diagnosis of Phytophthora ramorum involves sending samples to a laboratory for traditional isolation and morphological characterisation, and/or PCR analysis. This can take as long as 2 weeks from sampling to final diagnosis. However, the Plant Health Group, Central Science Laboratory, has produced on-site DNA extraction and real-time PCR (...

  12. Green Fluorescent Protein (GFP) as a reporter gene for the plant pathogenic oomycete Phytophthora ramorum

    Science.gov (United States)

    Marko Riedel; Gautier Calmin; Lassaad Belbahri; Francois Lefort; Monika Gotz; Stefan Wagner; Sabine. Werres

    2009-01-01

    Transgenic Phytophthora ramorum strains that produce green fluorescent protein (GFP) constitutively were obtained after stable DNA integration using a polyethylene glycol and CaCl2-based transformation protocol. Green fluorescent protein production was studied in developing colonies and in different propagules of the pathogen...

  13. Detection and identification of Phytophthora fragariae Hickman by the polymerase chain reaction

    NARCIS (Netherlands)

    Bonants, P.; Hagenaar-de Weerdt, M.; Gent-Pelzer, van M.; Lacourt, I.; Cooke, D.; Duncan, J.

    1997-01-01

    Phytophthora fragariae Hickman, which causes strawberry red stele and raspberry root rot, is a quarantine organism for which specific and sensitive detection methods are required to test the health of planting material. Sequences of the internal transcribed spacer regions of the ribosomal gene

  14. Identification, characterization and high-resolution mapping of resistance genes to Phytophthora infestans in potato

    NARCIS (Netherlands)

    Park, T.H.

    2005-01-01

    Potato ( Solanum tuberosum L.) is one of the most important crops in the world. The oomycete Phytophthora infestans (Mont. de Bary) is the causal agent of late blight which is the most devastating disease of the cultivated potato. It causes economic losses of several billion US dollars in crop

  15. Climate-Host Mapping of Phytophthora ramorum, causal agent of sudden oak death

    Science.gov (United States)

    Roger Magarey; Glenn Fowler; Manuel Colunga; Bill Smith; Ross Meentemeyer

    2008-01-01

    We modeled Phytophthora ramorum infection using the North Carolina State University- Animal and Plant Health Inspection Service Plant Pest Forecasting System (NAPPFAST) for the conterminous United States. Our infection model is based on a temperature-moisture response function. The model parameters were: leaf wetness, minimum temperature, optimum...

  16. Suppression of Phytophthora ramorum infestations through silvicultural treatment in California's north coast

    Science.gov (United States)

    Yana Valachovic; Chris Lee; Brendan Twieg; David Rizzo; Richard Cobb; Radoslaw Glebocki

    2013-01-01

    In 2006, three forested sites infested with Phytophthora ramorum in Humboldt County, California were subjected to different combinations of treatments designed to reduce inoculum and control spread. One treatment, consisting of removal of all California bay laurel (Umbellularia californica (Hook. & Arn.) Nutt.) and tanoak...

  17. THE INFLUENCE OF NATURAL ESSENTIAL OILS ON THE GROWTH OF PHYTOPHTHORA SPP. ISOLATED FROM PELARGONIUM CUTTINGS

    Directory of Open Access Journals (Sweden)

    Marcelina Machura

    2017-10-01

    Full Text Available Ornamental plants play an important role in human life. Plants positively influence the psyche and improve the well-being of people around them. They produce oxygen, provide a barrier to dust and noise, lower the temperature and increase air humidity, thereby positively impacting the microclimate. The unmatched appeal of pelargonium, ease of cultivation and care, abundance of flowering from spring to late autumn and its decorative qualities make it a universal application. The aim of the study was to isolate the microorganisms that inhabit the cuttings of pelargonium, identify fungal isolates, investigate the pathogenicity of selected isolates and evaluate the influence of certain essential oils (Carum carvi L. essential oils, Citrus limon L. essential oils, Citrus reticulatae aetheroleum essential oils, essential oil of tea tree in in vitro circumstances on the linear growth of the mycelium: Phytophthora cryptogea, Phytophthora nicotianae var. nicotianae. Previcur Energy 840 SL was used as a standard chemical protection. The most numerous isolated fungi were: Phytophthora, Botrytis, Cylindrocladium, Alternaria and Cylindrocarpon. The highest efficiency in relation to Phytophthora cryptogea characterized the Citrus limon L. essential oils (concentration 0.1% and 1% and Carum carvi L. essential oil (concentration 1%.

  18. A systems approach for detecting sources of Phytophthora contamination in nurseries

    Science.gov (United States)

    Jennifer L. Parke; Niklaus Grünwald; Carrie Lewis; Val Fieland

    2010-01-01

    Nursery plants are also important long-distance vectors of non-indigenous pathogens such as P. ramorum and P. kernoviae. Pre-shipment inspections have not been adequate to ensure that shipped plants are free from Phytophthora, nor has this method informed growers about sources of contamination in their...

  19. Phytophthora community structure analyses in Oregon nurseries inform systems approaches to disease management

    Science.gov (United States)

    J.L. Parke; B.J. Knaus; V.J. Fieland; C. Lewis; N.J. Grünwald

    2014-01-01

    Nursery plants are important vectors for plant pathogens. Understanding what pathogens occur in nurseries in different production stages can be useful to the development of integrated systems approaches. Four horticultural nurseries in Oregon were sampled every 2 months for 4 years to determine the identity and community structure of Phytophthora...

  20. Core Promoter Structure in the Oomycete Phytophthora infestans

    Science.gov (United States)

    McLeod, Adele; Smart, Christine D.; Fry, William E.

    2004-01-01

    We have investigated the core promoter structure of the oomycete Phytophthora infestans. The transcriptional start sites (TSS) of three previously characterized P. infestans genes, Piexo1, Piexo3, and Piendo1, were determined by primer extension analyses. The TSS regions were homologous to a previously identified 16-nucleotide (nt) core sequence that overlaps the TSS in most oomycete genes. The core promoter regions of Piexo1 and Piendo1 were investigated by using a transient protoplast expression assay and the reporter gene β-glucuronidase. Mutational analyses of the promoters of Piexo1 and Piendo1 showed that there is a putative core promoter element encompassing the TSS (−2 to + 5) that has high sequence and functional homology to a known core promoter element present in other eukaryotes, the initiator element (Inr). Downstream and flanking the Inr is a highly conserved oomycete promoter region (+7 to + 15), hereafter referred to as FPR (flanking promoter region), which is also important for promoter function. The importance of the 19-nt core promoter region (Inr and FPR) in Piexo1 and Piendo1 was further investigated through electrophoretic mobility shift assays (EMSA). The EMSA studies showed that (i) both core promoters were able to specifically bind a protein or protein complex in a P. infestans whole-cell protein extract and (ii) the same mutations that reduced binding of the EMSA complex also reduced β-glucuronidase (GUS) levels in transient expression assays. The consistency of results obtained using two different assays (GUS transient assays [in vivo] and EMSA studies [in vitro]) supports a convergence of inference about the relative importance of specific nucleotides within the 19-nt core promoter region. PMID:14871940

  1. Biological and epidemiological aspects of the quarantine pathogen Phytophthora ramorum

    Directory of Open Access Journals (Sweden)

    Beatrice Ginetti

    2015-12-01

    Full Text Available Phytophthora ramorum is a quarantine pathogen that causes leaf blight and shoot dieback of the crown, bark cankers and death on a number of both ornamental and forest trees, especially in North America and northern Europe, where it has produced severe outbreaks.In Italy it was first reported in 2002, on Rhodondendron yakushimanum in a Piedmont nursery; after that it seemed to have disappeared, only to re-emerge in 2013 when numerous isolates were detected on batches of Viburnum tinus plants growing in some nurseries in the Pistoia area (Tuscany, which is an important district in the trade of nursery plants world-wide. This work reports on a number of laboratory tests that were carried out on isolates from infected plant samples. The micromorphological and macromorphological characteristics of the pathogen growing on carrot agar (CA, corn meal agar (CMA, malt extract agar (MEA potato dextrose agar, and V8 agar with added PARPNH (see text were determined, as was the growth rate at 10º, 15º, 20º, 25°, 30º, 32º and 35ºC. Molecular analysis was employed to identify the isolates more precisely. Inoculation trials under the bark were also carried out to ascertain the isolate virulence and the Koch’s Postulates.The Plant Protection Service of the Tuscan Region (SFR, Servizio Fitosanitario Regionale was alerted as soon as the pathogen infection was detected and it took the prescribed steps to eradicate the infection in the field and prevent the recurrence of an epidemic.

  2. Genetic diversity of Phytophthora infestans in the Northern Andean region.

    Science.gov (United States)

    Cárdenas, Martha; Grajales, Alejandro; Sierra, Roberto; Rojas, Alejandro; González-Almario, Adriana; Vargas, Angela; Marín, Mauricio; Fermín, Gustavo; Lagos, Luz E; Grünwald, Niklaus J; Bernal, Adriana; Salazar, Camilo; Restrepo, Silvia

    2011-02-09

    Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana) and tree tomato (Solanum betaceum), all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a) and one mitochondrial (Cox1) region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

  3. Genetic diversity of Phytophthora infestans in the Northern Andean region

    Directory of Open Access Journals (Sweden)

    Grünwald Niklaus J

    2011-02-01

    Full Text Available Abstract Background Phytophthora infestans (Mont. de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana and tree tomato (Solanum betaceum, all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a and one mitochondrial (Cox1 region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Results Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. Conclusions The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

  4. Tracing the Transcriptomic Changes in Synthetic Trigenomic allohexaploids of Brassica Using an RNA-Seq Approach

    Science.gov (United States)

    Zhao, Qin; Zou, Jun; Meng, Jinling; Mei, Shiyong; Wang, Jianbo

    2013-01-01

    Polyploidization has played an important role in plant evolution and speciation, and newly formed allopolyploids have experienced rapid transcriptomic changes. Here, we compared the transcriptomic differences between a synthetic Brassica allohexaploid and its parents using a high-throughput RNA-Seq method. A total of 35,644,409 sequence reads were generated, and 32,642 genes were aligned from the data. Totals of 29,260, 29,060, and 29,697 genes were identified in Brassica rapa , Brassica carinata , and Brassica allohexaploid, respectively. We compared 7,397 differentially expressed genes (DEGs) between Brassica hexaploid and its parents, as well as 2,545 nonadditive genes of Brassica hexaploid. We hypothesized that the higher ploidy level as well as secondary polyploidy might have influenced these changes. The majority of the 3,184 DEGs between Brassica hexaploid and its paternal parent, B . rapa , were involved in the biosynthesis of secondary metabolites, plant–pathogen interactions, photosynthesis, and circadian rhythm. Among the 2,233 DEGs between Brassica hexaploid and its maternal parent, B . carinata , several played roles in plant–pathogen interactions, plant hormone signal transduction, ribosomes, limonene and pinene degradation, photosynthesis, and biosynthesis of secondary metabolites. There were more significant differences in gene expression between the allohexaploid and its paternal parent than between it and its maternal parent, possibly partly because of cytoplasmic and maternal effects. Specific functional categories were enriched among the 2,545 nonadditive genes of Brassica hexaploid compared with the additive genes; the categories included response to stimulus, immune system process, cellular process, metabolic process, rhythmic process, and pigmentation. Many transcription factor genes, methyltransferases, and methylation genes showed differential expression between Brassica hexaploid and its parents. Our results demonstrate that the

  5. Intraspecific Variation in Carotenoids of Brassica oleracea var. sabellica.

    Science.gov (United States)

    Mageney, Vera; Baldermann, Susanne; Albach, Dirk C

    2016-04-27

    Carotenoids are best known as a source of natural antioxidants. Physiologically, carotenoids are part of the photoprotection in plants as they act as scavengers of reactive oxygen species (ROS). An important source of carotenoids in European food is Brassica oleracea. Focusing on the most abundant carotenoids, we estimated the contents of ß-carotene, (9Z)-neoxanthin, zeaxanthin, and lutein as well as those of chlorophylls a and b to assess their variability in Brassica oleracea var. sabellica. Our analyses included more than 30 cultivars categorized in five distinct sets grouped according to morphological characteristics or geographical origin. Our results demonstrated specific carotenoid patterns characteristic for American, Italian, and red-colored kale cultivars. Moreover, we demonstrated a tendency of high zeaxanthin proportions under traditional harvest conditions, which accord to low-temperature regimes. We also compared the carotenoid patterns of self-generated hybrid lines. Corresponding findings indicated that crossbreeding has a high potential for carotenoid content optimization in kale.

  6. Erosion of Brassica incana Genetic Resources: Causes and Effects

    Science.gov (United States)

    Muscolo, A.; Settineri, G.; Mallamaci, C.; Papalia, T.; Sidari, M.

    2017-07-01

    Brassica incana Ten., possessing a number of useful agronomic traits, represents a precious genetic resource to be used in plant breeding programs to broaden the genetic base in most Brassica crop species. B. incana that grows on limestone cliffs is at risk of genetic erosion for environmental constraints and human activities. We studied the pedological conditions of a Calabrian site where the B. incana grows, and we correlated the soil properties to the physiological and biochemical aspects of B. incana to identify the causes and effects of the genetic erosion of this species. Our results evidenced that physical soil conditions did not affect B. incana growth and nutraceutical properties; conversely, biological soil properties modified its properties. We identified leaf pigments and secondary metabolites that can be used routinely as early warning indicators of plant threat, to evaluate in a short term the dynamic behavior of plants leading to species extinction.

  7. Effect of Heavy Metals in Plants of the Genus Brassica

    Science.gov (United States)

    Mourato, Miguel P.; Moreira, Inês N.; Leitão, Inês; Pinto, Filipa R.; Sales, Joana R.; Louro Martins, Luisa

    2015-01-01

    Several species from the Brassica genus are very important agricultural crops in different parts of the world and are also known to be heavy metal accumulators. There have been a large number of studies regarding the tolerance, uptake and defense mechanism in several of these species, notably Brassica juncea and B. napus, against the stress induced by heavy metals. Numerous studies have also been published about the capacity of these species to be used for phytoremediation purposes but with mixed results. This review will focus on the latest developments in the study of the uptake capacity, oxidative damage and biochemical and physiological tolerance and defense mechanisms to heavy metal toxicity on six economically important species: B. juncea, B. napus, B. oleracea, B. carinata, B. rapa and B. nigra. PMID:26247945

  8. Omics Approach to Identify Factors Involved in Brassica Disease Resistance.

    Science.gov (United States)

    Francisco, Marta; Soengas, Pilar; Velasco, Pablo; Bhadauria, Vijai; Cartea, Maria E; Rodríguez, Victor M

    2016-01-01

    Understanding plant's defense mechanisms and their response to biotic stresses is of fundamental meaning for the development of resistant crop varieties and more productive agriculture. The Brassica genus involves a large variety of economically important species and cultivars used as vegetable source, oilseeds, forage and ornamental. Damage caused by pathogens attack affects negatively various aspects of plant growth, development, and crop productivity. Over the last few decades, advances in plant physiology, genetics, and molecular biology have greatly improved our understanding of plant responses to biotic stress conditions. In this regard, various 'omics' technologies enable qualitative and quantitative monitoring of the abundance of various biological molecules in a high-throughput manner, and thus allow determination of their variation between different biological states on a genomic scale. In this review, we have described advances in 'omic' tools (genomics, transcriptomics, proteomics and metabolomics) in the view of conventional and modern approaches being used to elucidate the molecular mechanisms that underlie Brassica disease resistance.

  9. Development of Rapid Isothermal Amplification Assays for Detection of Phytophthora spp. in Plant Tissue.

    Science.gov (United States)

    Miles, Timothy D; Martin, Frank N; Coffey, Michael D

    2015-02-01

    Several isothermal amplification techniques recently have been developed that are tolerant of inhibitors present in many plant extracts, which can reduce the need for obtaining purified DNA for running diagnostic assays. One such commercially available technique that has similarities with real-time polymerase chain reaction (PCR) for designing primers and a labeled probe is recombinase polymerase amplification (RPA). This technology was used to develop two simple and rapid approaches for detection of Phytophthora spp.: one genus-specific assay multiplexed with a plant internal control and the other species-specific assays for Phytophthora ramorum and P. kernoviae. All assays were tested for sensitivity (ranging from 3 ng to 1 fg of DNA) and specificity using DNA extracted from more than 136 Phytophthora taxa, 21 Pythium spp., 1 Phytopythium sp., and a wide range of plant species. The lower limit of linear detection using purified DNA was 200 to 300 fg of DNA in all pathogen RPA assays. Six different extraction buffers were tested for use during plant tissue maceration and the assays were validated in the field by collecting 222 symptomatic plant samples from over 50 different hosts. Only 56 samples were culture positive for Phytophthora spp. whereas 91 were positive using the Phytophthora genus-specific RPA test and a TaqMan real-time PCR assay. A technique for the generation of sequencing templates from positive RPA amplifications to confirm species identification was also developed. These RPA assays have added benefits over traditional technologies because they are rapid (results can be obtained in as little as 15 min), do not require DNA extraction or extensive training to complete, use less expensive portable equipment than PCR-based assays, and are significantly more specific than current immunologically based methods. This should provide a rapid, field-deployable capability for pathogen detection that will facilitate point-of-sample collection processing

  10. Relationship between resistance to Phytophthora ramorum and constitutive phenolic chemistry in coast live oaks and northern red oaks

    Science.gov (United States)

    Annemarie M. Nagle; Matteo Garbelotto; Brice McPherson; David L. Wood; Pierluigi. Bonello

    2010-01-01

    Phytophthora ramorum causes lethal canker diseases and extensive mortality in coast live oak (CLO) (Quercus agrifolia) and tanoak (Lithocarpus densiflorus). No practical controls are available for this disease in non-urban environments. Therefore, characterization of natural resistance is highly...

  11. Phytophthora capsici - Loss of Heterozygosity (LOH): A Widespread Mechanism for Rapid Adaptation (7th Annual SFAF Meeting, 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Mudge, Joanne

    2012-06-01

    Joanne Mudge on "Phytophthora capsici - Loss of Heterozygosity (LOH): A Widespread Mechanism for Rapid Mutation" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  12. First detection in the USA: new plant pathogen, Phytophthora tentaculata, in native plant nurseries and restoration sites in California

    Science.gov (United States)

    S. Rooney-Latham; C. L. Blomquist; T. Swiecki; E. Bernhardt; S.J. Frankel

    2015-01-01

    Phytophthora tentaculata Kröber & Marwitz, has been detected in several native plant nurseries in 4 California counties and in restoration sites on orange sticky monkey flower (Diplacus aurantiacus subsp. aurantiacus (W. Curtis) Jeps. [Scrophulariaceae]), toyon (Heteromeles...

  13. Phytophthora ramorum infects tanoak sapwood and is associated with reduced sap flux and specific conductivity of xylem

    Science.gov (United States)

    Jennifer Parke; Eunsung Oh; Steve Voelker; Everett Hansen; Gerri Buckles; Barb Lachenbruch

    2008-01-01

    Culture, detection with diagnostic PCR, and microscopy demonstrated the presence of Phytophthora ramorum in the sapwood of mature, naturally infected tanoak (Lithocarpus densiflorus) trees in Curry County, Oregon. The pathogen was strongly associated with discolored sapwood (P

  14. Catalytic properties of three catalases from Kohlrabi ( Brassica ...

    African Journals Online (AJOL)

    Catalase (EC 1.11.1.6) was extracted from kohlrabi bulbs (Brassica oleracea gongylodes) with 0.05 M phosphate buffer, pH 7.0. On the basis of kinetic studies and activity stain for catalase, only three isoenzymes of catalases were detected in kohlrabi bulbs extract with pH optima at 4.5, 6.5 and 10. Highest catalytic ...

  15. Cadmium uptake potential of Brassica napus cocropped with Brassica parachinensis and Zea mays

    International Nuclear Information System (INIS)

    Selvam, Ammaiyappan; Wong, Jonathan Woon-Chung

    2009-01-01

    Cadmium uptake potential of Brassica napus cocropped with B. parachinensis or Zea mays plants in split pot (allow the solutes to pass but prevent the interaction of roots between compartments) experiments was evaluated. Plants were grown in split pots filled with soil spiked at 0, 3, 6, 12, 25 and 50 mg Cd/kg soil. Biomass and Cd uptake were detemined after 6 weeks, and rhizospheric soil solutions, extracted using soil probes, were analyzed for pH and water soluble Cd at weekly intervals. Cadmium treatments affected the biomass. Cadmium concentration in the shoots of B. napus was higher when cocropped with B. parachinensis and significantly higher with Z. mays; however, the biomass was negatively affected implying the higher nutrient apportionment to the crop plants than B. napus. Concentration of Cd in B. napus was higher in shoots than in roots as revealed by shoot/root Cd quotient and was always >1; the quotient for B. parachinensis was ∼1 and that of Z. mays was <1, indicating the potential of Brassicaceae members to translocate the Cd to aboveground tissue. Results indicate the feasibility of cocropping method to clean the Cd contaminated soils.

  16. Cadmium uptake potential of Brassica napus cocropped with Brassica parachinensis and Zea mays

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, Ammaiyappan [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong, (Hong Kong); Wong, Jonathan Woon-Chung, E-mail: jwcwong@hkbu.edu.hk [Sino-Forest Applied Research Centre for Pearl River Delta Environment, Department of Biology, Hong Kong Baptist University, Hong Kong (Hong Kong)

    2009-08-15

    Cadmium uptake potential of Brassica napus cocropped with B. parachinensis or Zea mays plants in split pot (allow the solutes to pass but prevent the interaction of roots between compartments) experiments was evaluated. Plants were grown in split pots filled with soil spiked at 0, 3, 6, 12, 25 and 50 mg Cd/kg soil. Biomass and Cd uptake were detemined after 6 weeks, and rhizospheric soil solutions, extracted using soil probes, were analyzed for pH and water soluble Cd at weekly intervals. Cadmium treatments affected the biomass. Cadmium concentration in the shoots of B. napus was higher when cocropped with B. parachinensis and significantly higher with Z. mays; however, the biomass was negatively affected implying the higher nutrient apportionment to the crop plants than B. napus. Concentration of Cd in B. napus was higher in shoots than in roots as revealed by shoot/root Cd quotient and was always >1; the quotient for B. parachinensis was {approx}1 and that of Z. mays was <1, indicating the potential of Brassicaceae members to translocate the Cd to aboveground tissue. Results indicate the feasibility of cocropping method to clean the Cd contaminated soils.

  17. COST action FP801- established and emerging Phytophthora: incresasing threats to woodland and forest ecosystems in Europe

    OpenAIRE

    Woodward, S.; Vannini, A.; Werres, S.; Osswald, W.; Bonants, P.J.M.; Jung, T.

    2011-01-01

    With the rapidly growing international trade in plants and ongoing impacts of climate change, impacts of plant pathogens in the genus Phytophthora are increasing, threatening the biodiversity and sustainability of European forest ecosystems. Through the European Cooperation in Science and Technology (COST) framework Action FP0801, scientists and disease-control experts are working on phytophthora in forest ecosystems with the overall aim of increasing understanding of the biology and ecology ...

  18. Control of Cocoa Pod Borer and Phytophthora Pod Rot Using Degradable Plastic Pod Sleeves and a Nematode, Steinernema Carpocapsae

    OpenAIRE

    Rosmana, Ade; Shepard, Merle; Hebbar, Prakash; Mustari, Anita

    2010-01-01

    Cocoa pod borer (CPB; Conopomorpha cramerella) and Phytophthora pod rot (PPR; Phytophthora palmivora) are serious pest and disease on cocoa plantations in Indonesia. Both pest and disease have been controlled with limited success using cultural practices such as pruning, frequent harvesting, sanitation, plastic sleeving, and chemical pesticides. An experiment was conducted on cocoa plantings in Pinrang Regency, South Sulawesi during the wet season of 2008/09 to test the effect of pod sleeving...

  19. Association mapping for #Phytophthora# pod rot resistance in a cacao (#Theobroma cacao# L.) population grown in farmers' field

    OpenAIRE

    Efombagn, Mousseni Ives Bruno; Sounigo, Olivier; Courtois, Brigitte; Fouet, Olivier; Jeanneau, Mélanie; Lemainque, Arnaud; Pavek, Sylvana; Lanaud, Claire

    2016-01-01

    Phytophthora pod rot (PPR) caused by the specie Phytophthora megakarya is an important disease of cacao tree. Association mapping identified markers linked to PPR resistance in a cacao population of 260 trees planted under high disease pressure in a single plantation in a farmer's field. These cacao trees were derived from both selfing and full-sib progenies. The resistance traits were assessed through field observations of the natural pod attacks of the disease on the trunk (PRTnk) or the ca...

  20. Genetic diversity assessment in brassica germplasm based on morphological attributes

    International Nuclear Information System (INIS)

    Ali, I.; Ali, N.; Ali, S.; Hussain, I.; Khan, S. A.; Tahira, R.

    2015-01-01

    Genetic diversity of 28 Brassica genotypes was studied using different morphological attributes. Data were recorded on days to maturity (DM), plant height (PH), primary branches plant (PBPP), pod length (PL), seed pod (SP), 1000 - seed weight (1000 - SW), yield plant (YPP) and oil (percentage). Three checks (Pakola, CM and TA), were used to check the performance of collected materials with already available brassica varieties. significant statistical differences were observed among the tested genotypes based on the studied morphological traits. Among the tested genotypes, genotype keelboat proved to be superior as compared to other studied genotypes due to maximum level of studied traits like pod length (7.03 cm), seed pod (32.33), 1000 - seed weight (5.38 g), seed yield plant (110.8 g) and oil content (52.9 percentage. The highest level of performance recorded by kalabat in terms of branches plant, pod length (cm), number of seed pod, seed yield plant (g), 1000 - seed weight (g) and oil content (percentage), indicates that this genotype is genetically different and superior than the other studied genotype. Therefore, genotype kalabat can be either used as variety after adaptability trials over a larger area or included in Brassica breeding programmes as a good source of genetic variation. (author)

  1. Isolate dependency of Brassica rapa resistance QTLs to Botrytis cinerea.

    Directory of Open Access Journals (Sweden)

    Wei eZhang

    2016-02-01

    Full Text Available Generalist necrotrophic pathogens including Botrytis cinerea cause significant yield and financial losses on Brassica crops. However, there is little knowledge about the mechanisms underlying the complex interactions encoded by both host and pathogen genomes in this interaction. This potentially includes multiple layers of plant defense and pathogen virulence mechanisms that could complicate in breeding broad spectrum resistance within Brassica species. Glucosinolates are a diverse group of defense metabolites that play a key role in interaction between Brassica and biotic attackers. In this study, we utilized a collection of diverse B. cinerea isolates to investigate resistance within the B. rapa R500 x IMB211 recombinant inbred line population. We tested variation on lesion development and glucosinolate accumulation in parental lines and all population lines. We then mapped quantitative trait loci (QTL for both resistances to B. cinerea and defense metabolites in this population. Phenotypic analysis and QTL mapping demonstrate that the genetic basis of resistance to B. cinerea in B. rapa is isolate specific and polygenic with transgressive segregation that both parents contribute resistance alleles. QTLs controlling defensive glucosinolates are highly dependent on pathogen infection. An overlap of two QTLs identified between resistance to B. cinerea and defense metabolites also showed isolate specific effects. This work suggests that directly searching for resistance loci may not be the best approach at improving resistance in B. rapa to necrotrophic pathogen.

  2. NEW ACCESSIONS OF BRASSICA OLERACEA L. IN VIR PLANT COLLECTION

    Directory of Open Access Journals (Sweden)

    A. M. Artemieva

    2017-01-01

    Full Text Available Varieties of Brassica oleracea L. are widespread and favorite crops, where among them the head cabbage and cauliflower are the most economically important. Russia takes third place after India and Chine among countries with largest production areas and gross yield for the crop. In Russia, the area sown to cabbage is about 27 thousand hectares. 728 cultivars and hybrids of eight cabbage crops including 528 hybrids have been added in State Register of Breeding Achievements of Russian Federation in 2017. The collection of Brassica oleracea L. totally contains of 2421 accessions and takes first place at number of collected items among the world’s plant genbanks. The phenotyping, genotyping, passportization, development of core collection and trait collection as well as initial breeding accessions, covering all genetic diversity have been carried out at department of genetic resources of vegetables and melons at VIR. Selection of most promising accessions is performed to find genes and sources for economically valuable traits to develop proper lines and hybrids. There are the enrichment of the collection by means of ordering and gathering in expeditions, the improvement of methods of phenotyping and development of database for all biological accessions studied at the department. In 2007-2016, 255 accessions of Brassica oleracea L. have been included into collection to be used in different national breeding programs.

  3. Transcriptome responses of an ungrafted Phytophthora root rot tolerant avocado (Persea americana) rootstock to flooding and Phytophthora cinnamomi.

    Science.gov (United States)

    Reeksting, B J; Olivier, N A; van den Berg, N

    2016-09-22

    Avocado (Persea americana Mill.) is a commercially important fruit crop worldwide. A major limitation to production is the oomycete Phytophthora cinnamomi, which causes root rot leading to branch-dieback and tree death. The decline of orchards infected with P. cinnamomi occurs much faster when exposed to flooding, even if flooding is only transient. Flooding is a multifactorial stress compromised of several individual stresses, making breeding and selection for tolerant varieties challenging. With more plantations occurring in marginal areas, with imperfect irrigation and drainage, understanding the response of avocado to these stresses will be important for the industry. Maintenance of energy production was found to be central in the response to flooding, as seen by up-regulation of transcripts related to glycolysis and induction of transcripts related to ethanolic fermentation. Energy-intensive processes were generally down-regulated, as evidenced by repression of transcripts related to processes such as secondary cell-wall biosynthesis as well as defence-related transcripts. Aquaporins were found to be down-regulated in avocado roots exposed to flooding, indicating reduced water-uptake under these conditions. The transcriptomic response of avocado to flooding and P. cinnamomi was investigated utilizing microarray analysis. Differences in the transcriptome caused by the presence of the pathogen were minor compared to transcriptomic perturbations caused by flooding. The transcriptomic response of avocado to flooding reveals a response to flooding that is conserved in several species. This data could provide key information that could be used to improve selection of stress tolerant rootstocks in the avocado industry.

  4. 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.

  5. Productivity and nutritive quality of three brassica varieties for use in pasture-based systems

    Science.gov (United States)

    Brassicas are gaining popularity among pasture-based livestock producers to extend grazing during the ‘summer slump’ and throughout the fall. A 2-yr study was conducted to compare biomass production and nutrient composition of ‘Barisca’ rapeseed (RAP; Brassica napus L.), ‘Inspiration’ canola (CAN; B...

  6. Effect of seed-irradiation on morphological characters yield components of brassica campestris var. sarson

    International Nuclear Information System (INIS)

    Bokhari, F.S.; Ahmad, S.

    1996-01-01

    Seed of Brassica campestris (var. Sarson) were used to study the effect of radiation of different morphological and yield parameters. Survival percentage showed drastic decrease at higher doses (75 Kr and 100 Kr). Similarly all characters showed a trend of decrease with increasing dose. LD50 for Brassica was about 50 Kr. (author)

  7. Enteric methane production and ruminal fermentation from forage brassica diets fed in continuous culture

    Science.gov (United States)

    Brassicas provide forage for livestock during the late fall when traditional perennial cool-season forages are not productive. However, little research exists on ruminal fermentation and methane(CH4) production of brassicas fed as forage. A continuous culture fermentor system was used to assess nutr...

  8. The genome of the mesopolyploid crop species Brassica rapa

    DEFF Research Database (Denmark)

    Wang, Xiaowu; Wang, Hanzhong; Wang, Jun

    2011-01-01

    We report the annotation and analysis of the draft genome sequence of Brassica rapa accession Chiifu-401-42, a Chinese cabbage. We modeled 41,174 protein coding genes in the B. rapa genome, which has undergone genome triplication. We used Arabidopsis thaliana as an outgroup for investigating...... of Brassica oil and vegetable crops....

  9. Variation and Distribution of Glucosinolates in 42 Cultivars of Brassica oleracea Vegetable Crops

    NARCIS (Netherlands)

    Verkerk, R.; Tebbenhoff, S.; Dekker, M.

    2010-01-01

    Brassica vegetables are known to contain glucosinolates that are precursors for bioactive compounds like isothiocyanates that have been shown to play an important role in human health. This study reports the results of a screening of 11 Brassica oleracea crops consisting of 42 cultivars (6 white

  10. Database derived microsatellite markers (SSRs) for cultivar differentiation in Brassica oleracea

    DEFF Research Database (Denmark)

    Louarn, Sébastien Jean Yves; Torp, Anna Maria; Holme, I.B.

    2007-01-01

     Fifty-nine Brassica oleracea cultivars, belonging to five botanical varieties, were evaluated for microsatellite (SSR) polymorphisms using 11 database sequence derived primer pairs. The cultivars represented 12 broccoli (Brassica oleracea var. italica), ten Brussels sprouts (B. o. var. gemmifera...

  11. Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana

    NARCIS (Netherlands)

    Ji, X.

    2014-01-01

    Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana.

    I studied numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and

  12. Integration of linkage maps for the Amphidiploid Brassica napus and comparative mapping with Arabidopsis and Brassica rapa

    Directory of Open Access Journals (Sweden)

    Delourme Régine

    2011-02-01

    Full Text Available Abstract Background The large number of genetic linkage maps representing Brassica chromosomes constitute a potential platform for studying crop traits and genome evolution within Brassicaceae. However, the alignment of existing maps remains a major challenge. The integration of these genetic maps will enhance genetic resolution, and provide a means to navigate between sequence-tagged loci, and with contiguous genome sequences as these become available. Results We report the first genome-wide integration of Brassica maps based on an automated pipeline which involved collation of genome-wide genotype data for sequence-tagged markers scored on three extensively used amphidiploid Brassica napus (2n = 38 populations. Representative markers were selected from consolidated maps for each population, and skeleton bin maps were generated. The skeleton maps for the three populations were then combined to generate an integrated map for each LG, comparing two different approaches, one encapsulated in JoinMap and the other in MergeMap. The BnaWAIT_01_2010a integrated genetic map was generated using JoinMap, and includes 5,162 genetic markers mapped onto 2,196 loci, with a total genetic length of 1,792 cM. The map density of one locus every 0.82 cM, corresponding to 515 Kbp, increases by at least three-fold the locus and marker density within the original maps. Within the B. napus integrated map we identified 103 conserved collinearity blocks relative to Arabidopsis, including five previously unreported blocks. The BnaWAIT_01_2010a map was used to investigate the integrity and conservation of order proposed for genome sequence scaffolds generated from the constituent A genome of Brassica rapa. Conclusions Our results provide a comprehensive genetic integration of the B. napus genome from a range of sources, which we anticipate will provide valuable information for rapeseed and Canola research.

  13. Comparative mapping of Brassica juncea and Arabidopsis thaliana using Intron Polymorphism (IP markers: homoeologous relationships, diversification and evolution of the A, B and C Brassica genomes

    Directory of Open Access Journals (Sweden)

    Gupta Vibha

    2008-03-01

    Full Text Available Abstract Background Extensive mapping efforts are currently underway for the establishment of comparative genomics between the model plant, Arabidopsis thaliana and various Brassica species. Most of these studies have deployed RFLP markers, the use of which is a laborious and time-consuming process. We therefore tested the efficacy of PCR-based Intron Polymorphism (IP markers to analyze genome-wide synteny between the oilseed crop, Brassica juncea (AABB genome and A. thaliana and analyzed the arrangement of 24 (previously described genomic block segments in the A, B and C Brassica genomes to study the evolutionary events contributing to karyotype variations in the three diploid Brassica genomes. Results IP markers were highly efficient and generated easily discernable polymorphisms on agarose gels. Comparative analysis of the segmental organization of the A and B genomes of B. juncea (present study with the A and B genomes of B. napus and B. nigra respectively (described earlier, revealed a high degree of colinearity suggesting minimal macro-level changes after polyploidization. The ancestral block arrangements that remained unaltered during evolution and the karyotype rearrangements that originated in the Oleracea lineage after its divergence from Rapa lineage were identified. Genomic rearrangements leading to the gain or loss of one chromosome each between the A-B and A-C lineages were deciphered. Complete homoeology in terms of block organization was found between three linkage groups (LG each for the A-B and A-C genomes. Based on the homoeology shared between the A, B and C genomes, a new nomenclature for the B genome LGs was assigned to establish uniformity in the international Brassica LG nomenclature code. Conclusion IP markers were highly effective in generating comparative relationships between Arabidopsis and various Brassica species. Comparative genomics between the three Brassica lineages established the major rearrangements

  14. The Large Subunit rDNA Sequence of Plasmodiophora brassicae Does not Contain Intra-species Polymorphism.

    Science.gov (United States)

    Schwelm, Arne; Berney, Cédric; Dixelius, Christina; Bass, David; Neuhauser, Sigrid

    2016-12-01

    Clubroot disease caused by Plasmodiophora brassicae is one of the most important diseases of cultivated brassicas. P. brassicae occurs in pathotypes which differ in the aggressiveness towards their Brassica host plants. To date no DNA based method to distinguish these pathotypes has been described. In 2011 polymorphism within the 28S rDNA of P. brassicae was reported which potentially could allow to distinguish pathotypes without the need of time-consuming bioassays. However, isolates of P. brassicae from around the world analysed in this study do not show polymorphism in their LSU rDNA sequences. The previously described polymorphism most likely derived from soil inhabiting Cercozoa more specifically Neoheteromita-like glissomonads. Here we correct the LSU rDNA sequence of P. brassicae. By using FISH we demonstrate that our newly generated sequence belongs to the causal agent of clubroot disease. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  15. Genome-wide Investigation of microRNAs and Their Targets in Brassica rapa ssp. pekinensis Root with Plasmodiophora brassicae Infection

    Directory of Open Access Journals (Sweden)

    Xiaochun Wei

    2016-07-01

    Full Text Available Increasing evidence has revealed that microRNAs play a pivotal role in the post transcriptional regulation of gene expression in response to pathogens in plants. However, there is little information available about the expression patterns of miRNAs and their targets in Chinese cabbage (Brassica rapa ssp. pekinensis under Plasmodiophora brassicae stress. In the present study, using deep sequencing and degradome analysis, a genome-wide identification of miRNAs and their targets during P. brassicae stress was performed. A total of 221 known and 93 potentially novel miRNAs were successfully identified from two root libraries of one control (635-10CK and P. brassicae-treated Chinese cabbage samples (635-10T. Of these, 14 known and 10 potentially novel miRNAs were found to be differentially expressed after P. brassicae treatment. Degradome analysis revealed that the 223 target genes of the 75 miRNAs could be potentially cleaved. KEGG (Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that the putative target genes of the miRNAs were predominately involved in selenocompound metabolism and plant hormone signal transduction. Then the expression of 12 miRNAs was validated by quantitative real-time PCR (qRT-PCR. These results provide insights into the miRNA-mediated regulatory networks underlying the stress response to the plant pathogen P. brassicae.

  16. A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans is a Member of the Puf Family of Translational Regulators

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Judelson, Howard S.

    2003-01-01

    and persisted in mature oospores. Expression was also observed in hyphal tips just prior to asexual sporulation, in sporangiophores, in mature sporangia, and in zoospores. The signal quickly disappeared once spores made the transition to hyphae after germination. Nutrient limitation did not induce the gene...

  17. Roles of small RNAs in soybean defense against Phytophthora sojae infection.

    Science.gov (United States)

    Wong, James; Gao, Lei; Yang, Yang; Zhai, Jixian; Arikit, Siwaret; Yu, Yu; Duan, Shuyi; Chan, Vicky; Xiong, Qin; Yan, Jun; Li, Shengben; Liu, Renyi; Wang, Yuanchao; Tang, Guiliang; Meyers, Blake C; Chen, Xuemei; Ma, Wenbo

    2014-09-01

    The genus Phytophthora consists of many notorious pathogens of crops and forestry trees. At present, battling Phytophthora diseases is challenging due to a lack of understanding of their pathogenesis. We investigated the role of small RNAs in regulating soybean defense in response to infection by Phytophthora sojae, the second most destructive pathogen of soybean. Small RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are universal regulators that repress target gene expression in eukaryotes. We identified known and novel small RNAs that differentially accumulated during P. sojae infection in soybean roots. Among them, miR393 and miR166 were induced by heat-inactivated P. sojae hyphae, indicating that they may be involved in soybean basal defense. Indeed, knocking down the level of mature miR393 led to enhanced susceptibility of soybean to P. sojae; furthermore, the expression of isoflavonoid biosynthetic genes was drastically reduced in miR393 knockdown roots. These data suggest that miR393 promotes soybean defense against P. sojae. In addition to miRNAs, P. sojae infection also resulted in increased accumulation of phased siRNAs (phasiRNAs) that are predominantly generated from canonical resistance genes encoding nucleotide binding-leucine rich repeat proteins and genes encoding pentatricopeptide repeat-containing proteins. This work identifies specific miRNAs and phasiRNAs that regulate defense-associated genes in soybean during Phytophthora infection. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  18. The Phytophthora mating hormone α2 is an antagonist of the counterhormone α1.

    Science.gov (United States)

    Zhang, Li; Yajima, Arata; Ojika, Makoto

    2016-06-01

    The crop destroyer Phytophthora uses mating hormones α1 and α2 to commence its sexual reproduction. The α1-induced sexual reproduction of the A2 mating type was unexpectedly found to be interfered with by the counterhormone α2 that the A2 type itself produces to induce the sexual reproduction of the A1 type. A plausible mechanism is proposed based on structure-activity relationships.

  19. Karakter Morfologi Dan Molekuler Isolat Phytophthora Palmivora Asal Kelapa Dan Kakao

    OpenAIRE

    MOTULO, HIASINTA FJ; S-SINAGA, MEITY; SUASTIKA, GEDE; ASWIDINNOOR, HAJRIAL; HARTANA, ALEX

    2007-01-01

    Morphology and molecular characteristics of P.palmivora isolates from coconut and cacaoPhytophthora palmivora, is the pathogen of coconut nutfall andcacao black pod diseases. This study was conducted to differentiate theisolates of P. palmivora from coconut and those from cacao fruit based onmorphology and molecular characteristics. Samples of nutfall of coconutand black pod of cacao were collected from Banyuwangi and JemberDistricts, East Java, Minahasa and Bolaang Mongondow Districts, ...

  20. Identification and characterization of microRNAs in oilseed rape (Brassica napus) responsive to infection with the pathogenic fungus Verticillium longisporum using Brassica AA (Brassica rapa) and CC (Brassica oleracea) as reference genomes.

    Science.gov (United States)

    Shen, Dan; Suhrkamp, Ina; Wang, Yu; Liu, Shenyi; Menkhaus, Jan; Verreet, Joseph-Alexander; Fan, Longjiang; Cai, Daguang

    2014-11-01

    Verticillium longisporum, a soil-borne pathogenic fungus, causes vascular disease in oilseed rape (Brassica napus). We proposed that plant microRNAs (miRNAs) are involved in the plant-V. longisporum interaction. To identify oilseed rape miRNAs, we deep-sequenced two small RNA libraries made from V. longisporum infected/noninfected roots and employed Brassica rapa and Brassica oleracea genomes as references for miRNA prediction and characterization. We identified 893 B. napus miRNAs representing 360 conserved and 533 novel miRNAs, and mapped 429 and 464 miRNAs to the AA and CC genomes, respectively. Microsynteny analysis with the conserved miRNAs and their flanking protein coding sequences revealed 137 AA-CC genome syntenic miRNA pairs and 61 AA and 42 CC genome-unique miRNAs. Sixty-two miRNAs were responsive to the V. longisporum infection. We present data for specific interactions and simultaneously reciprocal changes in the expression levels of the miRNAs and their targets in the infected roots. We demonstrate that miRNAs are involved in the plant-fungus interaction and that miRNA168-Argonaute 1 (AGO1) expression modulation might act as a key regulatory module in a compatible plant-V. longisporum interaction. Our results suggest that V. longisporum may have evolved a virulence mechanism by interference with plant miRNAs to reprogram plant gene expression and achieve infection. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  1. Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod induce similar reactions when infecting pods of a susceptible cacao genotype

    Science.gov (United States)

    Phytophthora megakarya (Pmeg) and Phytophthora palmivora (Ppal) cause black pod rot of Theobroma cacao. Of these two clade 4 species; Pmeg is more virulent and is displacing Ppal on cacao in many cacao production areas in Africa. To understand the advantages Pmeg has over Ppal, we compared symptom...

  2. The use of genus-specific amplicon pyrosequencing to assess phytophthora species diversity using eDNA from soil and water in Northern Spain.

    Science.gov (United States)

    Català, Santiago; Pérez-Sierra, Ana; Abad-Campos, Paloma

    2015-01-01

    Phytophthora is one of the most important and aggressive plant pathogenic genera in agriculture and forestry. Early detection and identification of its pathways of infection and spread are of high importance to minimize the threat they pose to natural ecosystems. eDNA was extracted from soil and water from forests and plantations in the north of Spain. Phytophthora-specific primers were adapted for use in high-throughput Sequencing (HTS). Primers were tested in a control reaction containing eight Phytophthora species and applied to water and soil eDNA samples from northern Spain. Different score coverage threshold values were tested for optimal Phytophthora species separation in a custom-curated database and in the control reaction. Clustering at 99% was the optimal criteria to separate most of the Phytophthora species. Multiple Molecular Operational Taxonomic Units (MOTUs) corresponding to 36 distinct Phytophthora species were amplified in the environmental samples. Pyrosequencing of amplicons from soil samples revealed low Phytophthora diversity (13 species) in comparison with the 35 species detected in water samples. Thirteen of the MOTUs detected in rivers and streams showed no close match to sequences in international sequence databases, revealing that eDNA pyrosequencing is a useful strategy to assess Phytophthora species diversity in natural ecosystems.

  3. Evaluation of chemical and biological agents for control of Phytophthora species on intact plants or detached leaves of rhododendron and lilac

    Science.gov (United States)

    R.G. Linderman; E.A. Davis

    2006-01-01

    The recent incidence of Ramorum blight, caused by Phytophthora ramorum, on many nursery crops has focused attention on improving management strategies against Phytophthora diseases in nurseries. We evaluated several chemical agents that target Oomycete pathogens for their capacity to inhibit infection of rhododendron or lilac...

  4. The current state of knowledge on operational sanitation measures to lower risk of Phytophthora ramorum spread and the need for further study

    Science.gov (United States)

    Yana Valachovic; Dave Rizzo; Brendan Twieg

    2013-01-01

    We are working to evaluate risks associated with human spread of the sudden oak death (SOD) pathogen, Phytophthora ramorum, to currently uninfested areas in California. Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murray) Parl.) root disease (POC RD), caused by Phytophthora lateralis, has brought...

  5. Mutation breeding against black pod (Phytophthora pod rot) disease of cacao (Theobroma cacao)

    International Nuclear Information System (INIS)

    Opeke, L.K.

    1977-01-01

    Black pod rot disease, caused by Phytophthora palmivora, is an important disease of cacao (Theobroma cacao L.) in Nigeria and other cacao producing countries of West Africa and Latin America. A naturally occurring source of genetic resistance to the disease has not been found. This paper completes the report, the first part of which was published in Induced Mutations in Vegetatively Propagated Plants, IAEA, Vienna (1973). The survivors of the irradiated seedlings reported on in this publication were transplanted to the field along with their controls. When the Phytophthora pod disease season began in 1973, all experimental plants along with the controls were sprayed with active and freshly prepared dense sporangial suspension of P. palmivora. Observations on Phytophthora infection were recorded at two-weekly intervals for three months. Results were pooled for each set of experimental plants, after having confirmed that no marked difference appeared among individual plants of each group. Contrary to the observations recorded at the nursery stage, all experimental plants that showed no infection indicated disease infection levels normally characteristic of the F 3 Amazon cultivar of Cacao in Nigeria. Although the nursery and the field data are difficult to reconcile and interpret, it is suggested that probably temporary disease tolerance/resistance, which some irradiated plants showed at the nursery (seedling) stage, was lost as the plants matured, thus suggesting different resistance factor systems for juvenile and mature cacao trees. (author)

  6. Identification and Characterisation CRN Effectors in Phytophthora capsici Shows Modularity and Functional Diversity.

    Directory of Open Access Journals (Sweden)

    Remco Stam

    Full Text Available Phytophthora species secrete a large array of effectors during infection of their host plants. The Crinkler (CRN gene family encodes a ubiquitous but understudied class of effectors with possible but as of yet unknown roles in infection. To appreciate CRN effector function in Phytophthora, we devised a simple Crn gene identification and annotation pipeline to improve effector prediction rates. We predicted 84 full-length CRN coding genes and assessed CRN effector domain diversity in sequenced Oomycete genomes. These analyses revealed evidence of CRN domain innovation in Phytophthora and expansion in the Peronosporales. We performed gene expression analyses to validate and define two classes of CRN effectors, each possibly contributing to infection at different stages. CRN localisation studies revealed that P. capsici CRN effector domains target the nucleus and accumulate in specific sub-nuclear compartments. Phenotypic analyses showed that few CRN domains induce necrosis when expressed in planta and that one cell death inducing effector, enhances P. capsici virulence on Nicotiana benthamiana. These results suggest that the CRN protein family form an important class of intracellular effectors that target the host nucleus during infection. These results combined with domain expansion in hemi-biotrophic and necrotrophic pathogens, suggests specific contributions to pathogen lifestyles. This work will bolster CRN identification efforts in other sequenced oomycete species and set the stage for future functional studies towards understanding CRN effector functions.

  7. A paralogous decoy protects Phytophthora sojae apoplastic effector PsXEG1 from a host inhibitor.

    Science.gov (United States)

    Ma, Zhenchuan; Zhu, Lin; Song, Tianqiao; Wang, Yang; Zhang, Qi; Xia, Yeqiang; Qiu, Min; Lin, Yachun; Li, Haiyang; Kong, Liang; Fang, Yufeng; Ye, Wenwu; Wang, Yan; Dong, Suomeng; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2017-02-17

    The extracellular space (apoplast) of plant tissue represents a critical battleground between plants and attacking microbes. Here we show that a pathogen-secreted apoplastic xyloglucan-specific endoglucanase, PsXEG1, is a focus of this struggle in the Phytophthora sojae -soybean interaction. We show that soybean produces an apoplastic glucanase inhibitor protein, GmGIP1, that binds to PsXEG1 to block its contribution to virulence. P. sojae , however, secretes a paralogous PsXEG1-like protein, PsXLP1, that has lost enzyme activity but binds to GmGIP1 more tightly than does PsXEG1, thus freeing PsXEG1 to support P. sojae infection. The gene pair encoding PsXEG1 and PsXLP1 is conserved in many Phytophthora species, and the P. parasitica orthologs PpXEG1 and PpXLP1 have similar functions. Thus, this apoplastic decoy strategy may be widely used in Phytophthora pathosystems. Copyright © 2017, American Association for the Advancement of Science.

  8. Cross-species global proteomics reveals conserved and unique processes in Phytophthora sojae and P. ramorum

    Energy Technology Data Exchange (ETDEWEB)

    Savidor, Alon [ORNL; Donahoo, Ryan S [ORNL; Hurtado-Gonzales, Oscar [University of Tennessee, Knoxville (UTK); Land, Miriam L [ORNL; Shah, Manesh B [ORNL; Lamour, Kurt H [ORNL; McDonald, W Hayes [ORNL

    2008-08-01

    Phytophthora ramorum and Phytophthora sojae are destructive plant pathogens. Phytophthora sojae has a narrow host range whereas P. ramorum has a wide host range. A global proteomic comparison of the vegetative (mycelium) and infective (germinating-cyst) life-stages of P. sojae and P. ramorum was conducted to identify candidate proteins involved in host range, early infection and vegetative growth. Sixty-two candidates for early infection, 26 candidates for vegetative growth, and numerous proteins that may be involved in defining host specificity were identified. In addition, common life stage proteomic trends between the organisms were observed. In mycelia, proteins involved in transport and metabolism of amino acids, carbohydrates and other small molecules were up-regulated. In the germinating cysts, up-regulated proteins associated with lipid transport and metabolism, cytoskeleton and protein synthesis were observed. It appears that the germinating cyst catabolizes lipid reserves through the -oxidation pathway to drive the extensive protein synthesis necessary to produce the germ tube and initiate infection. Once inside the host, the pathogen switches to vegetative growth, where energy is derived from glycolysis and utilized for synthesis of amino acids and other molecules that assist survival in the plant tissue.

  9. Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

    Directory of Open Access Journals (Sweden)

    Daniel D. Rosa

    2007-01-01

    Full Text Available Due to the economic importance of gummosis disease for the citriculture, studies on P. parasitica-Citrus interaction comprise a significant part in the Brazilian Citrus genome data bank (CitEST. Among them, two cDNA libraries constructed from two different growth conditions of the P. parasitica pathogen are included which has generated the PP/CitEST database (CitEST - Center APTA Citros Sylvio Moreira/IAC- Millennium Institute. Through this genomic approach and clustering analyses the following has been observed: out of a total of 13,285 available in the Phytophthora parasitica database, a group of 4,567 clusters was formed, comprising 2,649 singlets and 1,918 contigs. Out of a total of 4,567 possible genes, only 2,651 clusters were categorized; among them, only 4.3% shared sequence similarities with pathogenicity factors and defense. Some of these possible genes (103 corresponding to 421 ESTs, were characterized by phylogenetic analysis and discussed. A comparison made with the COGEME database has shown homology which may be part of an evolutionary pathogenicity pathway present in Phytophthora and also in other fungi. Many of the genes which were identified here, which may encode proteins associated to mechanisms of citrus gummosis pathogenicity, represent only one facet of the pathogen-host Phytophthora - Citrus interaction.

  10. Pathways to false-positive diagnoses using molecular genetic detection methods; Phytophthora cinnamomi a case study.

    Science.gov (United States)

    Kunadiya, Manisha; White, Diane; Dunstan, William A; Hardy, Giles E St J; Andjic, Vera; Burgess, Treena I

    2017-04-01

    Phytophthora cinnamomi is one of the world's most invasive plant pathogens affecting ornamental plants, horticultural crops and natural ecosystems. Accurate diagnosis is very important to determine the presence or absence of this pathogen in diseased and asymptomatic plants. In previous studies, P. cinnamomi species-specific primers were designed and tested using various polymerase chain reaction (PCR) techniques including conventional PCR, nested PCR and quantitative real-time PCR. In all cases, the primers were stated to be highly specific and sensitive to P. cinnamomi. However, few of these studies tested their primers against closely related Phytophthora species (Phytophthora clade 7). In this study, we tested these purported P. cinnamomi-specific primer sets against 11 other species from clade 7 and determined their specificity; of the eight tested primer sets only three were specific to P. cinnamomi. This study demonstrated the importance of testing primers against closely related species within the same clade, and not just other species within the same genus. The findings of this study are relevant to all species-specific microbial diagnosis. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Neem (Azadirachta indica a. Juss) components: candidates for the control of Crinipellis perniciosa and Phytophthora ssp.

    Science.gov (United States)

    de Rezende Ramos, Alessandra; Lüdke Falcão, Loeni; Salviano Barbosa, Guilherme; Helena Marcellino, Lucilia; Silvano Gander, Eugen

    2007-01-01

    Witches' broom and pod rot are the two most devastating diseases of cocoa in South America and Africa, respectively. Their control by means of phytosanitation and chemical fungicides is labor-intensive, costly and, in many cases, environmentally undesirable. Therefore efforts are made in order to identify alternative, environmentally safe and cost-efficient methods for the control of these pathogens. Promising candidates are components of the neem tree (Azadirachta indica), that have been used for centuries in Asia as insecticides, fungicides, anticonceptionals in popular medicine. Here we report about tests on the effect of various concentrations of extracts from neem leaves on growth of mycelia of Crinipellis and Phytophthora and on germination of spores of Crinipellis. We show a 35% growth reduction of mycelia of Phytophthora on neem leaf extract media, whereas growth of mycelia of Crinipellis was not affected, even at the highest concentration of neem leaf extracts used (35%). However, the most dramatic effect of neem leaf extracts is observed on Crinipellis spore germination, here the extracts (20-35%) reduced germination almost completely. Based on these results, we believe that the neem tree might be a source for the production, on small and medium scale, of an effective and cheap formulation for the control of Crinipellis and Phytophthora.

  12. Morphological and molecular identification of phytophthora species from maple trees in Serbia

    Directory of Open Access Journals (Sweden)

    Milenković Ivan

    2014-01-01

    Full Text Available The paper presents the results of the study performed with aims to determine the presence and diversity of Phytophthora species on maple trees in Serbia. Due to high aggressiveness and their multicyclic nature, presence of these pathogens is posing significant threat to forestry and biodiversity. In total, 29 samples of water, soil and tissues were taken from 10 different localities, and six different maple hosts were tested. After the isolation tests, 17 samples from five different maple hosts were positive for the presence of Phytophthora spp., and 31 isolates were obtained. After the detailed morphological and physiological classification, four distinct groups of isolates were separated. DNA was extracted from selected representative isolates and molecular identification with sequencing of ITS region was performed. Used ITS4 and ITS6 primers successfully amplified the genomic DNA of chosen isolates and morphological identification of obtained isolates was confirmed after the sequencing. Four different Phytophthora species were detected, including P. cactorum, P. gonapodyides, P. plurivora and P. lacustris. The most common isolated species was homothallic, and with very variable and semipapillate sporangia, P. plurivora with 22 obtained isolates. This is the first report of P. plurivora and P. gonapodyides on A. campestre, P. plurivora and P. lacustris on Acer heldreichii and first report of P. lacustris on A. pseudoplatanus and A. tataricum in Serbia. [Projekat Ministarstva nauke Republike Srbije, br. TR 37008

  13. Phytophthora parsiana sp. nov., a new high-temperature tolerant species.

    Science.gov (United States)

    Mostowfizadeh-Ghalamfarsa, R; Cooke, D E L; Banihashemi, Z

    2008-07-01

    As part of a study to examine the phylogenetic history of the taxonomically challenging species Phytophthora cryptogea and P. drechsleri, a distinct monophyletic group of isolates, previously described as P. drechsleri or P. cryptogea, were characterised. Analysis of their rDNA ITS sequences indicated that these isolates were distinct from P. drechsleri, P. cryptogea, and all members of Phytophthora ITS clades 1-8, clustering instead alongside basal groups previously described as clades 9 and 10. This group comprised six isolates all of which were isolated from woody plants, such as pistachio (Pistacia vera, Iran and USA), fig (Ficus carica, Iran), and almond (Prunus dulcis, Greece). Analysis of sequence data from nuclear (beta-tubulin and translation elongation factor 1alpha) and mitochondrial (cytochrome c oxidase subunit I) genes confirmed the ITS-based analysis as these isolates formed a distinct monophyletic group in all NJ trees. The isolates were fast growing with a relatively high optimum growth temperature of 30 degrees C and, in most cases, rapid colony growth even at 37 degrees C. The isolates produced complex colony patterns on almost all media, especially corn meal agar (CMA). Phylogenetic analysis and examination of all the other morphological and physiological data lead us to infer that this taxon has not been described previously. As this taxon was first isolated and described from Iran we propose that this taxon be formally designated as Phytophthora parsiana.

  14. Real-Time Polymerase Chain Reaction Quantification of Phytophthora capsici in Different Pepper Genotypes.

    Science.gov (United States)

    Silvar, C; Díaz, J; Merino, F

    2005-12-01

    ABSTRACT Reliable and sensitive quantification of Phytophthora capsici in pepper plants is of crucial importance in managing the multiple syndromes caused by this pathogen. A real-time polymerase chain reaction (PCR) assay was developed for the determination of P. capsici in pepper tissues. DNA levels of a highly virulent and a less virulent isolate were measured in different pepper genotypes with varying degrees of resistance. Using SYBR Green and specific primers for P. capsici, the minimal amount of pathogen DNA quantified was 10 pg. Pathogen DNA was recorded as early as 8 h postinoculation. Thereafter, the increase was rapid in susceptible cultivars and slower in resistant ones. The amount of pathogen DNA quantified in each pepper genotype correlated with susceptibility to Phytophthora root rot. Likewise, there was a relationship between the virulence of the pathogen and the degree of colonization. Differences also were found in oomycete amount among pepper tissues, with maximal pathogen biomass occurring in stems. The real-time PCR technique developed in this study was sensitive and robust enough to assess both pathogen development and resistance to Phytophthora root rot in different pepper genotypes.

  15. A novel Capsicum gene inhibits host-specific disease resistance to Phytophthora capsici.

    Science.gov (United States)

    Reeves, Gregory; Monroy-Barbosa, Ariadna; Bosland, Paul W

    2013-05-01

    A novel disease resistance inhibitor gene (inhibitor of P. capsici resistance [Ipcr]), found in the chile pepper (Capsicum annuum) variety 'New Mexico Capsicum Accession 10399' (NMCA10399), inhibits resistance to Phytophthora capsici but not to other species of Phytophthora. When a highly P. capsici-resistant variety was hybridized with NMCA10399, the resultant F1 populations, when screened, were completely susceptible to P. capsici for root rot and foliar blight disease syndromes, despite the dominance inheritance of P. capsici resistance in chile pepper. The F2 population displayed a 3:13 resistant-to-susceptible (R:S) ratio. The testcross population displayed a 1:1 R:S ratio, and a backcross population to NMCA10399 displayed complete susceptibility. These results demonstrate the presence of a single dominant inhibitor gene affecting P. capsici resistance in chile pepper. Moreover, when lines carrying the Ipcr gene were challenged against six Phytophthora spp., the nonhost resistance was not overcome. Therefore, the Ipcr gene is interfering with host-specific resistance but not the pathogen- or microbe-associated molecular pattern nonhost responses.

  16. Mitochondrial genome sequences reveal evolutionary relationships of the Phytophthora 1c clade species.

    Science.gov (United States)

    Lassiter, Erica S; Russ, Carsten; Nusbaum, Chad; Zeng, Qiandong; Saville, Amanda C; Olarte, Rodrigo A; Carbone, Ignazio; Hu, Chia-Hui; Seguin-Orlando, Andaine; Samaniego, Jose A; Thorne, Jeffrey L; Ristaino, Jean B

    2015-11-01

    Phytophthora infestans is one of the most destructive plant pathogens of potato and tomato globally. The pathogen is closely related to four other Phytophthora species in the 1c clade including P. phaseoli, P. ipomoeae, P. mirabilis and P. andina that are important pathogens of other wild and domesticated hosts. P. andina is an interspecific hybrid between P. infestans and an unknown Phytophthora species. We have sequenced mitochondrial genomes of the sister species of P. infestans and examined the evolutionary relationships within the clade. Phylogenetic analysis indicates that the P. phaseoli mitochondrial lineage is basal within the clade. P. mirabilis and P. ipomoeae are sister lineages and share a common ancestor with the Ic mitochondrial lineage of P. andina. These lineages in turn are sister to the P. infestans and P. andina Ia mitochondrial lineages. The P. andina Ic lineage diverged much earlier than the P. andina Ia mitochondrial lineage and P. infestans. The presence of two mitochondrial lineages in P. andina supports the hybrid nature of this species. The ancestral state of the P. andina Ic lineage in the tree and its occurrence only in the Andean regions of Ecuador, Colombia and Peru suggests that the origin of this species hybrid in nature may occur there.

  17. EFFECT OF EXTRACTS FROM GERANIACEAE PLANTS ON PIERIS BRASSICAE L.

    Directory of Open Access Journals (Sweden)

    MARIA WAWRZYNIAK

    2010-06-01

    Full Text Available The conducted studies comprised the analyses of activity of extracts derived from selected plants of the Geranium family on some processes of large white butterfly (Pieris brassicae development (oviposition, survival of eggs and caterpillar feeding. The results proved that all tested extracts showed activity against large white butterfly. Geranium pratense L. and Geranium senquineum L. showed better activity than other Geranium plants. Water extracts from these species protected cabbage plants against laying eggs, while applied on eggs caused their mortality. Alcohol and water extracts from G. pratense L. and water extracts from G. senquineum L. increased an amount of food put on mass gain of caterpillars.

  18. Alternaria resistance of Brassicae campestris L. improved by induced mutations

    International Nuclear Information System (INIS)

    Das, M.L.; Rahman, A.

    1989-01-01

    Full text: Seeds of 'YS 52', a cultivar susceptible to Alternaria brassicae (Berk.) Sacc., were exposed to gamma rays (30-90 kR). Eight more resistant mutants were selected in M3 and subjected to further field evaluation. The best mutant '17-5-83' appeared resistant and gave 44% higher yield than the parent, mutant '70-7-82' was found to be moderately resistant and gave a yield 21% higher than the parent. The yield increases seem to be connected with plant architecture changes. (author)

  19. Tracing the transcriptomic changes in synthetic Trigenomic allohexaploids of Brassica using an RNA-Seq approach.

    Directory of Open Access Journals (Sweden)

    Qin Zhao

    Full Text Available Polyploidization has played an important role in plant evolution and speciation, and newly formed allopolyploids have experienced rapid transcriptomic changes. Here, we compared the transcriptomic differences between a synthetic Brassica allohexaploid and its parents using a high-throughput RNA-Seq method. A total of 35,644,409 sequence reads were generated, and 32,642 genes were aligned from the data. Totals of 29,260, 29,060, and 29,697 genes were identified in Brassicarapa, Brassicacarinata, and Brassica allohexaploid, respectively. We compared 7,397 differentially expressed genes (DEGs between Brassica hexaploid and its parents, as well as 2,545 nonadditive genes of Brassica hexaploid. We hypothesized that the higher ploidy level as well as secondary polyploidy might have influenced these changes. The majority of the 3,184 DEGs between Brassica hexaploid and its paternal parent, B. rapa, were involved in the biosynthesis of secondary metabolites, plant-pathogen interactions, photosynthesis, and circadian rhythm. Among the 2,233 DEGs between Brassica hexaploid and its maternal parent, B. carinata, several played roles in plant-pathogen interactions, plant hormone signal transduction, ribosomes, limonene and pinene degradation, photosynthesis, and biosynthesis of secondary metabolites. There were more significant differences in gene expression between the allohexaploid and its paternal parent than between it and its maternal parent, possibly partly because of cytoplasmic and maternal effects. Specific functional categories were enriched among the 2,545 nonadditive genes of Brassica hexaploid compared with the additive genes; the categories included response to stimulus, immune system process, cellular process, metabolic process, rhythmic process, and pigmentation. Many transcription factor genes, methyltransferases, and methylation genes showed differential expression between Brassica hexaploid and its parents. Our results demonstrate that the

  20. Functional, genetic and chemical characterization of biosurfactants produced by plant growth-promoting Pseudomonas putida 267

    NARCIS (Netherlands)

    Kruijt, M.; Tran, H.; Raaijmakers, J.M.

    2009-01-01

    Aims: Plant growth-promoting Pseudomonas putida strain 267, originally isolated from the rhizosphere of black pepper, produces biosurfactants that cause lysis of zoospores of the oomycete pathogen Phytophthora capsici. The biosurfactants were characterized, the biosynthesis gene(s) partially

  1. Genome-wide identification of aquaporin encoding genes in Brassica oleracea and their phylogenetic sequence comparison to Brassica crops and Arabidopsis

    Science.gov (United States)

    Diehn, Till A.; Pommerrenig, Benjamin; Bernhardt, Nadine; Hartmann, Anja; Bienert, Gerd P.

    2015-01-01

    Aquaporins (AQPs) are essential channel proteins that regulate plant water homeostasis and the uptake and distribution of uncharged solutes such as metalloids, urea, ammonia, and carbon dioxide. Despite their importance as crop plants, little is known about AQP gene and protein function in cabbage (Brassica oleracea) and other Brassica species. The recent releases of the genome sequences of B. oleracea and Brassica rapa allow comparative genomic studies in these species to investigate the evolution and features of Brassica genes and proteins. In this study, we identified all AQP genes in B. oleracea by a genome-wide survey. In total, 67 genes of four plant AQP subfamilies were identified. Their full-length gene sequences and locations on chromosomes and scaffolds were manually curated. The identification of six additional full-length AQP sequences in the B. rapa genome added to the recently published AQP protein family of this species. A phylogenetic analysis of AQPs of Arabidopsis thaliana, B. oleracea, B. rapa allowed us to follow AQP evolution in closely related species and to systematically classify and (re-) name these isoforms. Thirty-three groups of AQP-orthologous genes were identified between B. oleracea and Arabidopsis and their expression was analyzed in different organs. The two selectivity filters, gene structure and coding sequences were highly conserved within each AQP subfamily while sequence variations in some introns and untranslated regions were frequent. These data suggest a similar substrate selectivity and function of Brassica AQPs compared to Arabidopsis orthologs. The comparative analyses of all AQP subfamilies in three Brassicaceae species give initial insights into AQP evolution in these taxa. Based on the genome-wide AQP identification in B. oleracea and the sequence analysis and reprocessing of Brassica AQP information, our dataset provides a sequence resource for further investigations of the physiological and molecular functions of

  2. High-throughput multiplex cpDNA resequencing clarifies the genetic diversity and genetic relationships among Brassica napus, Brassica rapa and Brassica oleracea.

    Science.gov (United States)

    Qiao, Jiangwei; Cai, Mengxian; Yan, Guixin; Wang, Nian; Li, Feng; Chen, Binyun; Gao, Guizhen; Xu, Kun; Li, Jun; Wu, Xiaoming

    2016-01-01

    Brassica napus (rapeseed) is a recent allotetraploid plant and the second most important oilseed crop worldwide. The origin of B. napus and the genetic relationships with its diploid ancestor species remain largely unresolved. Here, chloroplast DNA (cpDNA) from 488 B. napus accessions of global origin, 139 B. rapa accessions and 49 B. oleracea accessions were populationally resequenced using Illumina Solexa sequencing technologies. The intraspecific cpDNA variants and their allelic frequencies were called genomewide and further validated via EcoTILLING analyses of the rpo region. The cpDNA of the current global B. napus population comprises more than 400 variants (SNPs and short InDels) and maintains one predominant haplotype (Bncp1). Whole-genome resequencing of the cpDNA of Bncp1 haplotype eliminated its direct inheritance from any accession of the B. rapa or B. oleracea species. The distribution of the polymorphism information content (PIC) values for each variant demonstrated that B. napus has much lower cpDNA diversity than B. rapa; however, a vast majority of the wild and cultivated B. oleracea specimens appeared to share one same distinct cpDNA haplotype, in contrast to its wild C-genome relatives. This finding suggests that the cpDNA of the three Brassica species is well differentiated. The predominant B. napus cpDNA haplotype may have originated from uninvestigated relatives or from interactions between cpDNA mutations and natural/artificial selection during speciation and evolution. These exhaustive data on variation in cpDNA would provide fundamental data for research on cpDNA and chloroplasts. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  3. Morphological and molecular identification of Phytophthora species isolated from the rhizosphere of declining oak trees in Krotoszyn Plateau

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2017-01-01

    Full Text Available The following paper presents the results on the determination of the diversity of species from the Phytophthora genus occurring in the declining oak stands in Krotoszyn Plateau in Poland. From the 50s of the last century, significant deterioration of oak health was observed in these stands, and Phytophthora species were suggested as one of the factors of the decline. In order to determine the presence of pathogenic organisms from the Phytophthora genus in these stands, 180 rhizosphere soil samples from three forest districts throughout the Krotoszyn Plateau were collected and subjected to the isolation method. Phytophthora species were consistently isolated from all the sampled stands, and 194 isolates from 111 positive samples were obtained. However, 150 (77% and 44 (23% isolates originated from the samples taken under the symptomatic and asymptomatic trees, respectively. All the obtained isolates were morphologically classified using the light and scanning electron microscopy and divided into morphological groups. Genomic DNA was isolated from selected isolates representing each group, ITS regions were amplified and sequence analyses were performed. In total, four different Phytophthora species were detected, including P. cactorum, P. plurivora, P. quercina and P. europaea. The most often isolated species were P. cactorum and P. plurivora. This is the first report of P. europaea in oak stands in Poland.

  4. Co-occurrence and genotypic distribution of Phytophthora species recovered from watersheds and plant nurseries of eastern Tennessee.

    Science.gov (United States)

    Hulvey, Jon; Gobena, Daniel; Finley, Ledare; Lamour, Kurt

    2010-01-01

    In 2008 statewide surveys of symptomatic foliage of nursery plants from Tennessee resulted in isolation of 43 isolates of Phytophthora spp. This sample set includes four described species (P. citrophthora, P. citricola, P. nicotianae, P. syringae), and a provisional species of Phytophthora ('P. hydropathica'). At the same time a stream-baiting survey was initiated to recover Phytophthora from eight watersheds in eastern Tennessee, some of which are near plant nurseries. Baiting was accomplished by submerging healthy Rhododendron leaves approximately 1 wk and isolation onto selective media. Six baiting periods were completed, and in total 98 Phytophthora isolates and 45 isolates of Pythium spp. were recovered. Three described species (P. citrophthora, P. citricola and P. irrigata) and the provisional species 'P. hydropathica' were obtained as well as three undescribed Phytophthora taxa and Pythium litorale. Isolates from both surveys were identified to species with morphology and the internal transcribed spacer (ITS) sequence. Isolates from species co-occurring in streams and nurseries (P. citricola, P. citrophthora and 'P. hydropathica') were characterized further with amplified fragment length polymorphism (AFLP) analyses and mefenoxam tolerance assays. Isolates representing a putative clonal genotype of P. citricola were obtained from both environmental and nursery sample sets.

  5. Species from within the Phytophthora cryptogea complex and related species, P. erythroseptica and P. sansomeana, readily hybridize.

    Science.gov (United States)

    Safaiefarahani, Banafsheh; Mostowfizadeh-Ghalamfarsa, Reza; Hardy, Giles E St J; Burgess, Treena I

    2016-08-01

    During a study on the phylogenetic relationships between species in the Phytophthora cryptogea complex and related species, Phytophthora erythroseptica and Phytophthora sansomeana, 19 hybrid isolates with multiple polymorphisms in the nuclear sequences were observed. Molecular characterization of hybrids was achieved by sequencing three nuclear (internal transcribed spacers, β-tubulin (TUB), heat shock protein 90) and two mitochondrial (cytochrome c oxidase subunit I (coxI), NADH dehydrogenase subunit I (NADH)) gene regions and cloning of the single-copy nuclear gene, TUB. Based on the molecular studies the hybrid isolates belonged to six distinct groups between P. cryptogea, P. erythroseptica, Phytophthora pseudocryptogea, P. sansomeana, and Phytophthora sp. kelmania. In all cases, only a single coxI and NADH allele was detected and nuclear genes were biparentally inherited, suggesting that the hybrids arose from sexual recombination events. Colony morphology, growth rate, cardinal temperatures, breeding system, and morphology of sporangia, oogonia, oospores, and antheridia were also determined. Some morphological differences between the hybrids and the parental species were noted; however, they were not sufficient to reliably distinguish the taxa and DNA markers from nuclear and mitochondrial genes will to be necessary for their identification. The parental species are all important pathogens of agricultural fields that have been transported globally. With the apparent ease of hybridization within this group there is ample opportunity for virulent hybrids to form, perhaps with extended host ranges. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  6. Pyrosequencing as a tool for the detection of Phytophthora species: error rate and risk of false Molecular Operational Taxonomic Units.

    Science.gov (United States)

    Vettraino, A M; Bonants, P; Tomassini, A; Bruni, N; Vannini, A

    2012-11-01

    To evaluate the accuracy of pyrosequencing for the description of Phytophthora communities in terms of taxa identification and risk of assignment for false Molecular Operational Taxonomic Units (MOTUs). Pyrosequencing of Internal Transcribed Spacer 1 (ITS1) amplicons was used to describe the structure of a DNA mixture comprising eight Phytophthora spp. and Pythium vexans. Pyrosequencing resulted in 16 965 reads, detecting all species in the template DNA mixture. Reducing the ITS1 sequence identity threshold resulted in a decrease in numbers of unmatched reads but a concomitant increase in the numbers of false MOTUs. The total error rate was 0·63% and comprised mainly mismatches (0·25%) Pyrosequencing of ITS1 region is an efficient and accurate technique for the detection and identification of Phytophthora spp. in environmental samples. However, the risk of allocating false MOTUs, even when demonstrated to be low, may require additional validation with alternative detection methods. Phytophthora spp. are considered among the most destructive groups of invasive plant pathogens, affecting thousands of cultivated and wild plants worldwide. Simultaneous early detection of Phytophthora complexes in environmental samples offers an unique opportunity for the interception of known and unknown species along pathways of introduction, along with the identification of these organisms in invaded environments. © 2012 The Authors Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  7. Water-stable diblock polystyrene-block-poly(2-vinyl pyridine) and diblock polystyrene-block-poly(methyl methacrylate) cylindrical patterned surfaces inhibit settlement of zoospores of the green alga Ulva.

    Science.gov (United States)

    Grozea, Claudia M; Gunari, Nikhil; Finlay, John A; Grozea, Daniel; Callow, Maureen E; Callow, James A; Lu, Zheng-Hong; Walker, Gilbert C

    2009-04-13

    Nanopatterned surfaces with hydrophobic and hydrophilic domains were produced using the diblock copolymer polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) and polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA). The PS-b-P2VP diblock copolymer, mixed with the cross-linker benzophenone and spin-coated onto silicon wafers, showed self-assembled cylindrical structures, which were retained after UV treatment for cross-linking. The thin films displayed cylindrical domains after immersion in water. This study shows that pattern retention in water is possible for a long period of time, at least for two weeks in pure water and three weeks in artificial seawater. The PS-b-PMMA diblock showed self-assembled cylindrical structures. PS-b-P2VP and PS-b-PMMA cylindrical patterned surfaces showed reduced settlement of zoospores of the green alga Ulva compared to unpatterned surfaces. The copolymers were investigated using atomic force microscopy and X-ray photoelectron spectroscopy.

  8. Identification of seed-related QTL in Brassica rapa

    Directory of Open Access Journals (Sweden)

    H. Bagheri

    2013-10-01

    Full Text Available To reveal the genetic variation, and loci involved, for a range of seed-related traits, a new F2 mapping population was developed by crossing Brassica rapa ssp. parachinensis L58 (CaiXin with B. rapa ssp. trilocularis R-o-18 (spring oil seed, both rapid flowering and self-compatible. A linkage map was constructed using 97 AFLPs and 21 SSRs, covering a map distance of 757 cM with an average resolution of 6.4 cM, and 13 quantitative trait loci (QTL were detected for nine traits. A strong seed colour QTL (LOD 26 co-localized with QTL for seed size (LOD 7, seed weight (LOD 4.6, seed oil content (LOD 6.6, number of siliques (LOD 3 and number of seeds per silique (LOD 3. There was only a significant positive correlation between seed colour and seed oil content in the yellow coloured classes. Seed coat colour and seed size were controlled by the maternal plant genotype. Plants with more siliques tended to have more, but smaller, seeds and higher seed oil content. Seed colour and seed oil content appeared to be controlled by two closely linked loci in repulsion phase. Thus, it may not always be advantageous to select for yellow-seededness when breeding for high seed oil content in Brassicas.

  9. A proteomic analysis of seed development in Brassica campestri L.

    Directory of Open Access Journals (Sweden)

    Wenlan Li

    Full Text Available To gain insights into the protein dynamics during seed development, a proteomic study on the developing Brassica campestri L. seeds with embryos in different embryogenesis stages was carried out. The seed proteins at 10, 16, 20, 25 and 35 DAP (days after pollination, respectively, were separated using two-dimensional gel electrophoresis and identities of 209 spots with altered abundance were determined by matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS. These proteins were classified into 16 groups according to their functions. The most abundant proteins were related to primary metabolism, indicating the heavy demand of materials for rapid embryo growth. Besides, the high amount of proteins involved in protein processing and destination indicated importance of protein renewal during seed development. The remaining were those participated in oxidation/detoxification, energy, defense, transcription, protein synthesis, transporter, cell structure, signal transduction, secondary metabolism, transposition, DNA repair, storage and so on. Protein abundance profiles of each functional class were generated and hierarchical cluster analysis established 8 groups of dynamic patterns. Our results revealed novel characters of protein dynamics in seed development in Brassica campestri L. and provided valuable information about the complex process of seed development in plants.

  10. Conserved microstructure of the Brassica B Genome of Brassica nigra in relation to homologous regions of Arabidopsis thaliana, B. rapa and B. oleracea

    Science.gov (United States)

    2013-01-01

    Background The Brassica B genome is known to carry several important traits, yet there has been limited analyses of its underlying genome structure, especially in comparison to the closely related A and C genomes. A bacterial artificial chromosome (BAC) library of Brassica nigra was developed and screened with 17 genes from a 222 kb region of A. thaliana that had been well characterised in both the Brassica A and C genomes. Results Fingerprinting of 483 apparently non-redundant clones defined physical contigs for the corresponding regions in B. nigra. The target region is duplicated in A. thaliana and six homologous contigs were found in B. nigra resulting from the whole genome triplication event shared by the Brassiceae tribe. BACs representative of each region were sequenced to elucidate the level of microscale rearrangements across the Brassica species divide. Conclusions Although the B genome species separated from the A/C lineage some 6 Mya, comparisons between the three paleopolyploid Brassica genomes revealed extensive conservation of gene content and sequence identity. The level of fractionation or gene loss varied across genomes and genomic regions; however, the greatest loss of genes was observed to be common to all three genomes. One large-scale chromosomal rearrangement differentiated the B genome suggesting such events could contribute to the lack of recombination observed between B genome species and those of the closely related A/C lineage. PMID:23586706

  11. Survival of pathogens of Brussels sprouts (Brassica oleracea Gemifera group) in crop residues

    NARCIS (Netherlands)

    Köhl, J.; Vlaswinkel, M.E.T.; Groenenboom-de Haas, B.H.; Kastelein, P.; Hoof, van R.A.; Wolf, van der J.M.; Krijger, M.C.

    2011-01-01

    Mycosphaerella brassicicola (ringspot), Alternaria brassicicola and A. brassicae (dark leaf spot) and Xanthomonas campestris pv. campestris (black spot) can infect leaves of Brussels sprouts resulting in yield losses. Infections of outer leaves of sprouts cause severe losses in quality. Crop

  12. Genetic variation in the hTAS2R38 taste receptor and brassica vegetable intake

    DEFF Research Database (Denmark)

    Gorovic, Nela; Afzal, Shoaib; Tjonneland, Anne

    2011-01-01

    The human TAS2R38 receptor is believed to be partly responsible for the ability to taste phenylthiocarbamide (PTC), a bitter compound very similar to the bitter glucosinolates found in brassica vegetables. These vegetables and their active compounds have chemo-protective properties. This study...... investigated the relationship between genetic variation in the hTAS2R38 receptor and the actual consumption of brassica vegetables with the hypothesis that taster status was associated with intake of these vegetables. Furthermore, secondary intake information on alcohol, chocolate, coffee, smoking, BMI...... on their brassica vegetables intake from the upper quartile (>= a parts per thousand yen23 g/day) and the lower quartile (brassicas from a randomly selected sub-cohort of DCH. DNA was analysed for three functional SNPs in the hTAS2R38 gene. The hTAS2R38...

  13. Seasonal Effects on Bioactive Compounds and Antioxidant Capacity of Six Economically Important Brassica Vegetables

    Directory of Open Access Journals (Sweden)

    Eduardo A.S. Rosa

    2011-08-01

    Full Text Available Research on natural and bioactive compounds is increasingly focused on their effects on human health, but there are unexpectedly few studies evaluating the relationship between climate and natural antioxidants. The aim of this study was analyze the biological role of six different Brassica vegetables (Brassica oleracea L. and Brassica rapa L. as a natural source of antioxidant compounds. The antioxidant activity may be assigned to high levels of L-ascorbic acid, total phenolics and total flavonoids of each sample. The climate seasons affected directly the concentration of bioactive components and the antioxidant activity. Broccoli inflorescences and Portuguese kale showed high antioxidant activity in Spring-Summer whilst turnip leaves did so in Summer-Winter. The Brassica vegetables can provide considerable amounts of bioactive compounds and thus may constitute an important natural source of dietary antioxidants.

  14. Varietal improvement of Brassica species through introduction, hybridization and mutation breeding techniques

    International Nuclear Information System (INIS)

    Rhaman, A.

    1988-11-01

    Germplasm of Brassica campestris and Brassica juncea was collected from various parts of Bangladesh and evaluated for yield, oil content etc. prior to the breeding programme. Seeds of the B. campestris variety YS-52, possessing good agronomic characteristics, were treated with mutagens (gamma rays and sodium azide) to widen the genetic variation. Mutants were selected for higher yield and resistance against Alternaria brassicae. The two mutant lines BINA 1 and BINA 2 were selected exceeding the parent variety considerably in yield and disease resistance. They are candidates for recommended varieties. Brassica juncea variety RCM 625 was treated with gamma rays and EMS. Four higher yielding and earlier maturing mutants are being evaluated further. 6 tabs

  15. Lycosides, Unusual Carotenoid-Derived Terpenoid Glycosides from a Vegetable Juice, Inhibit Asexual Reproduction of the Plant Pathogen Phytophthora.

    Science.gov (United States)

    Iwai, Rika; Han, Chunguang; Govindam, Sudhakar V S; Ojika, Makoto

    2018-01-10

    Vegetable juices, typical culture media for the plant pathogen Phytophthora, effectively induce its asexual reproduction (zoosporangia formation). However, some chromatographic fractions from a vegetable juice were found to inhibit asexual reproduction. Bioassay-guided chromatographic steps led to the isolation of four novel compounds, named lycosides A-D, 1-4, that could be metabolic products from a carotenoid. They showed 50% inhibitory activity against the asexual reproduction of P. capsici at 2.1-7.6 μM. The structure-activity relationship and the universality of the inhibitory activity within the Phytophthora genus were also investigated. In addition, the quantitative analysis of lycosides in fresh vegetables and vegetable juices revealed that tomato is the source of these active substances. These food-derived chemicals could help provide safe agents to control the outbreak of the agricultural pest Phytophthora in fields.

  16. Identification and characterization of mobile genetic elements LINEs from Brassica genome.

    Science.gov (United States)

    Nouroz, Faisal; Noreen, Shumaila; Khan, Muhammad Fiaz; Ahmed, Shehzad; Heslop-Harrison, J S Pat

    2017-09-05

    Among transposable elements (TEs), the LTR retrotransposons are abundant followed by non-LTR retrotransposons in plant genomes, the lateral being represented by LINEs and SINEs. Computational and molecular approaches were used for the characterization of Brassica LINEs, their diversity and phylogenetic relationships. Four autonomous and four non-autonomous LINE families were identified and characterized from Brassica. Most of the autonomous LINEs displayed two open reading frames, ORF1 and ORF2, where ORF1 is a gag protein domain, while ORF2 encodes endonuclease (EN) and a reverse transcriptase (RT). Three of four families encoded an additional RNase H (RH) domain in pol gene common to 'R' and 'I' type of LINEs. The PCR analyses based on LINEs RT fragments indicate their high diversity and widespread occurrence in tested 40 Brassica cultivars. Database searches revealed the homology in LINE sequences in closely related genera Arabidopsis indicating their origin from common ancestors predating their separation. The alignment of 58 LINEs RT sequences from Brassica, Arabidopsis and other plants depicted 4 conserved domains (domain II-V) showing similarity to previously detected domains. Based on RT alignment of Brassica and 3 known LINEs from monocots, Brassicaceae LINEs clustered in separate clade, further resolving 4 Brassica-Arabidopsis specific families in 2 sub-clades. High similarities were observed in RT sequences in the members of same family, while low homology was detected in members across the families. The investigation led to the characterization of Brassica specific LINE families and their diversity across Brassica species and their cultivars. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Pathogen-associated molecular pattern-triggered immunity and resistance to the root pathogen Phytophthora parasitica in Arabidopsis.

    Science.gov (United States)

    Larroque, Mathieu; Belmas, Elodie; Martinez, Thomas; Vergnes, Sophie; Ladouce, Nathalie; Lafitte, Claude; Gaulin, Elodie; Dumas, Bernard

    2013-09-01

    The cellulose binding elicitor lectin (CBEL) of the genus Phytophthora induces necrosis and immune responses in several plant species, including Arabidopsis thaliana. However, the role of CBEL-induced responses in the outcome of the interaction is still unclear. This study shows that some of CBEL-induced defence responses, but not necrosis, required the receptor-like kinase BAK1, a general regulator of basal immunity in Arabidopsis, and the production of a reactive oxygen burst mediated by respiratory burst oxidases homologues (RBOH). Screening of a core collection of 48 Arabidopsis ecotypes using CBEL uncovered a large variability in CBEL-induced necrotic responses. Analysis of non-responsive CBEL lines Ws-4, Oy-0, and Bla-1 revealed that Ws-4 and Oy-0 were also impaired in the production of the oxidative burst and expression of defence genes, whereas Bla-1 was partially affected in these responses. Infection tests using two Phytophthora parasitica strains, Pp310 and Ppn0, virulent and avirulent, respectively, on the Col-0 line showed that BAK1 and RBOH mutants were susceptible to Ppn0, suggesting that some immune responses controlled by these genes, but not CBEL-induced cell death, are required for Phytophthora parasitica resistance. However, Ws-4, Oy-0, and Bla-1 lines were not affected in Ppn0 resistance, showing that natural variability in CBEL responsiveness is not correlated to Phytophthora susceptibility. Overall, the results uncover a BAK1- and RBOH-dependent CBEL-triggered immunity essential for Phytophthora resistance and suggest that natural quantitative variation of basal immunity triggered by conserved general elicitors such as CBEL does not correlate to Phytophthora susceptibility.

  18. Mitochondrial genome sequencing helps show the evolutionary mechanism of mitochondrial genome formation in Brassica

    Science.gov (United States)

    2011-01-01

    Background Angiosperm mitochondrial genomes are more complex than those of other organisms. Analyses of the mitochondrial genome sequences of at least 11 angiosperm species have showed several common properties; these cannot easily explain, however, how the diverse mitotypes evolved within each genus or species. We analyzed the evolutionary relationships of Brassica mitotypes by sequencing. Results We sequenced the mitotypes of cam (Brassica rapa), ole (B. oleracea), jun (B. juncea), and car (B. carinata) and analyzed them together with two previously sequenced mitotypes of B. napus (pol and nap). The sizes of whole single circular genomes of cam, jun, ole, and car are 219,747 bp, 219,766 bp, 360,271 bp, and 232,241 bp, respectively. The mitochondrial genome of ole is largest as a resulting of the duplication of a 141.8 kb segment. The jun mitotype is the result of an inherited cam mitotype, and pol is also derived from the cam mitotype with evolutionary modifications. Genes with known functions are conserved in all mitotypes, but clear variation in open reading frames (ORFs) with unknown functions among the six mitotypes was observed. Sequence relationship analysis showed that there has been genome compaction and inheritance in the course of Brassica mitotype evolution. Conclusions We have sequenced four Brassica mitotypes, compared six Brassica mitotypes and suggested a mechanism for mitochondrial genome formation in Brassica, including evolutionary events such as inheritance, duplication, rearrangement, genome compaction, and mutation. PMID:21988783

  19. In vitro activity of glucosinolates and their degradation products against brassica-pathogenic bacteria and fungi.

    Science.gov (United States)

    Sotelo, T; Lema, M; Soengas, P; Cartea, M E; Velasco, P

    2015-01-01

    Glucosinolates (GSLs) are secondary metabolites found in Brassica vegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about their in vitro biocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enriched Brassica crops on suppressing in vitro growth of two bacterial (Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. maculicola) and two fungal (Alternaria brassicae and Sclerotinia scletoriorum) Brassica pathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of different Brassica species, have potential to inhibit pathogen growth and offer new opportunities to study the use of Brassica crops in biofumigation for the control of multiple diseases. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. A comparative map viewer integrating genetic maps for Brassica and Arabidopsis

    Directory of Open Access Journals (Sweden)

    Erwin Timothy A

    2007-07-01

    Full Text Available Abstract Background Molecular genetic maps provide a means to link heritable traits with underlying genome sequence variation. Several genetic maps have been constructed for Brassica species, yet to date, there has been no simple means to compare this information or to associate mapped traits with the genome sequence of the related model plant, Arabidopsis. Description We have developed a comparative genetic map database for the viewing, comparison and analysis of Brassica and Arabidopsis genetic, physical and trait map information. This web-based tool allows users to view and compare genetic and physical maps, search for traits and markers, and compare genetic linkage groups within and between the amphidiploid and diploid Brassica genomes. The inclusion of Arabidopsis data enables comparison between Brassica maps that share no common markers. Analysis of conserved syntenic blocks between Arabidopsis and collated Brassica genetic maps validates the application of this system. This tool is freely available over the internet on http://bioinformatics.pbcbasc.latrobe.edu.au/cmap. Conclusion This database enables users to interrogate the relationship between Brassica genetic maps and the sequenced genome of A. thaliana, permitting the comparison of genetic linkage groups and mapped traits and the rapid identification of candidate genes.

  1. Structure, anti-Phytophthora and anti-tumor activities of a nortriterpenoid from the rhizome of Phlomis purpurea (Lamiaceae).

    Science.gov (United States)

    Mateus, Maria C; Neves, Dina; Dacunha, Bruno; Laczko, Endre; Maia, Cristiana; Teixeira, Rúben; Cravador, Alfredo

    2016-11-01

    To investigate bioactive compounds potentially involved in the biotic interactions exhibited by Phlomis purpurea (Lamiaceae) in rhizospheres infested with Phytophthora cinnamomi, the plant rhizome was chemically analysed. The nortriterpenoid (17S)-2α,3α,11α,23,24-pentahydroxy-19(18 → 17)-abeo-28-norolean-12-en-18-one, was isolated and its structure was elucidated by comprehensive spectroscopic analysis, chiefly using 2D NMR experiments, and X-ray analysis. It was shown to be exuded by roots and to exhibit anti-Phytophthora and antitumor activities. Copyright © 2016. Published by Elsevier Ltd.

  2. The CAZyome of Phytophthora spp.: A comprehensive analysis of the gene complement coding for carbohydrate-active enzymes in species of the genus Phytophthora

    Directory of Open Access Journals (Sweden)

    Laird Emma W

    2010-09-01

    Full Text Available Abstract Background Enzymes involved in carbohydrate metabolism include Carbohydrate esterases (CE, Glycoside hydrolases (GH, Glycosyl transferases (GT, and Polysaccharide lyases (PL, commonly referred to as carbohydrate-active enzymes (CAZymes. The CE, GH, and PL superfamilies are also known as cell wall degrading enzymes (CWDE due to their role in the disintegration of the plant cell wall by bacterial and fungal pathogens. In Phytophthora infestans, penetration of the plant cells occurs through a specialized hyphal structure called appressorium; however, it is likely that members of the genus Phytophthora also use CWDE for invasive growth because hyphal forces are below the level of tensile strength exhibited by the plant cell wall. Because information regarding the frequency and distribution of CAZyme coding genes in Phytophthora is currently unknown, we have scanned the genomes of P. infestans, P. sojae, and P. ramorum for the presence of CAZyme-coding genes using a homology-based approach and compared the gene collinearity in the three genomes. In addition, we have tested the expression of several genes coding for CE in cultures grown in vitro. Results We have found that P. infestans, P. sojae and P. ramorum contain a total of 435, 379, and 310 CAZy homologs; in each genome, most homologs belong to the GH superfamily. Most GH and PL homologs code for enzymes that hydrolyze substances present in the pectin layer forming the middle lamella of the plant cells. In addition, a significant number of CE homologs catalyzing the deacetylation of compounds characteristic of the plant cell cuticle were found. In general, a high degree of gene location conservation was observed, as indicated by the presence of sequential orthologous pairs in the three genomes. Such collinearity was frequently observed among members of the GH superfamily. On the other hand, the CE and PL superfamilies showed less collinearity for some of their putative members

  3. Cytological and morphological analysis of hybrids between Brassicoraphanus, and Brassica napus for introgression of clubroot resistant trait into Brassica napus L.

    Science.gov (United States)

    Zhan, Zongxiang; Nwafor, Chinedu Charles; Hou, Zhaoke; Gong, Jianfang; Zhu, Bin; Jiang, Yingfen; Zhou, Yongming; Wu, Jiangsheng; Piao, Zhongyun; Tong, Yue; Liu, Chao; Zhang, Chunyu

    2017-01-01

    Interspecific hybridization is a powerful tool for improvement of crop species, it has the potential to broaden the genetic base and create new plant forms for breeding programs. Synthetic allopolyploid is a widely-used model for the study of genetic recombination and fixed heterosis in Brassica. In Brassica napus breeding, identification and introgression of new sources of clubroot resistance trait from wild or related species into it by hybridization is a long-term crop management strategy for clubroot disease. Radish (Raphanus sativus L.) is a close relative of the Brassica and most radish accessions are immune to the clubroot disease. A synthesized allotetraploid Brassicoraphanus (RRCC, 2n = 36) between R. sativus cv. HQ-04 (2n = 18, RR) and Brassica oleracea var. alboglabra (L.H Bailey) (2n = 18, CC) proved resistant of multiple clubroot disease pathogen P. brassicae. To predict the possibility to transfer the clubroot resistance trait from the RR subgenome of allotetraploid Brassicoraphanus (RRCC, 2n = 36) into Brassica napus (AACC, 2n = 38), we analyzed the frequency of chromosome pairings in the F1 hybrids produced from a cross between B. napus cv. HS5 and the allotetraploid, characterize the genomic composition of some backcrossed progeny (BC1) using GISH, BAC-FISH and AFLP techniques. The level of intergenomic pairing between A and R genomes in the F1 hybrid was high, allosyndetic bivalents formed in 73.53% PMCs indicative of significant level of homeologous recombination between two genomes and high probability of incorporating chromosomal segments/genes from R-genome into A/C-genomes. The BC1 plants inherited variant extra R chromosomes or fragments from allotetraploid as revealed by GISH and AFLP analysis. 13.51% BC2 individuals were resistant to clubroot disease, and several resistance lines had high pollen fertility, Overall, the genetic material presented in this work represents a potential new genetic resource for practical use in breeding B. napus

  4. Resistance to Phytophthora in mutant lines of currant tomato and in their original forms

    International Nuclear Information System (INIS)

    Khrustaleva, V.V.; Shcherbakov, V.K.

    1987-01-01

    Information on the production of currant tomato mutants is contained in a previous report. Evaluation of fruit resistance against Phytophthora infestans (Mont.) de Bary was carried out with pathotypes T 0 and T 1 . For artificial infection we used mainly a culture of T 1 (isolate 275), supplied by the Byelorussian Scientific Research Institute of Potato, Fruit and Vegetable Growing at Samokhvalovich. As inoculum for T 0 , a local population of the potato pathotype from the village of Shebantsevo, Moscow province was used. The standard variety 'Gruntovyj gribovskij 1180' was used as the control. Green fruits were taken from the first or second raceme of 20 plants. They were inoculated by spraying in plastic cuvettes with moist filter paper. The cuvettes were covered with glass and maintained at temperature of 18-20 deg. C. The results were checked 5, 9 and 12 days after inoculation. Under natural conditions, each of the 20 plants was also evaluated. As result, three lines with increased resistance to Phytophthora were selected from the original wild-type of currant tomato. Induced mutant forms were tested in the same way for resistance to Phytophthora. Data is presented from 4 years study. Of 26 mutant lines studied, we identified seven whose fruit displayed a stable and enhanced resistance to Phytophthora under both laboratory and field conditions. With regard to leaf infection of these lines, positive results were not obtained. There appears to be no direct relationship between resistance to Phytophthora of the fruit and the leaves. The mutant lines are of determinate type with early and medium ripening time. The average fruit weight is 5-33 g; in the case of the original specimen, it is only 0.9-1.7 g. The fruits have a pleasant sour-sweet taste and a thick skin. It is noteworthy that the mutant lines selected on the basis of their suitability for cultivation not only showed the resistance selected from the wild-type, but in a number of cases even turned out to

  5. Antifungal activity of salaceyin A against Colletotrichum orbiculare and Phytophthora capsici.

    Science.gov (United States)

    Park, C N; Lee, D; Kim, W; Hong, Y; Ahn, J S; Kim, B S

    2007-08-01

    The antifungal activities of novel salicylic acid derivatives, salaceyin A, 6-(9-methyldecyl) salicylic acid, and salaceyin B, 6-(9-methylundecyl) salicylic acid were evaluated against plant pathogenic fungi. Salaceyin A showed antifungal activity against Cladosporium cucumerinum, Colletotrichum orbiculare and Phytophthora capsici at 64 microg ml(-1) while salaceyin B was less effective. In vitro antifungal activities of the compounds were influenced by the experimental pH value of the MIC test medium wherein their antifungal activities were enhanced by increasingly acidic conditions. Salaceyin A showed potent in vivo control efficacy against Phytophthora blight in pepper plants. The disease was effectively suppressed at 500 microg ml(-1), which was comparable to the commercial fungicide, metalaxyl. Salaceyin A suppressed anthracnose development on cucumber leaves in a concentration dependent manner. The control efficacy of salaceyin A against C. orbiculare infection was similar to chlorothalonil when applied prior to pathogen inoculation. Since the salaceyins are derivatives of salicylic acid, a known important signal molecule critical to plant defenses against pathogen invasion, we investigated the possibility that exogenous application of the salaceyin A would activate a systemic acquired resistance against P. capsici infection and C. orbiculare development on pepper and cucumber plants respectively. The addition of 500 microg ml(-1) of salaceyin A to the plant root systems did not significantly decrease disease development in the hosts. We are led to conclude that the disease control efficacy of salaceyin A against the Phytophthora blight and anthracnose diseases, mainly originates from the direct interaction of the agent with the pathogens.

  6. Phytophthora have distinct endogenous small RNA populations that include short interfering and microRNAs.

    Directory of Open Access Journals (Sweden)

    Noah Fahlgren

    Full Text Available In eukaryotes, RNA silencing pathways utilize 20-30-nucleotide small RNAs to regulate gene expression, specify and maintain chromatin structure, and repress viruses and mobile genetic elements. RNA silencing was likely present in the common ancestor of modern eukaryotes, but most research has focused on plant and animal RNA silencing systems. Phytophthora species belong to a phylogenetically distinct group of economically important plant pathogens that cause billions of dollars in yield losses annually as well as ecologically devastating outbreaks. We analyzed the small RNA-generating components of the genomes of P. infestans, P. sojae and P. ramorum using bioinformatics, genetic, phylogenetic and high-throughput sequencing-based methods. Each species produces two distinct populations of small RNAs that are predominantly 21- or 25-nucleotides long. The 25-nucleotide small RNAs were primarily derived from loci encoding transposable elements and we propose that these small RNAs define a pathway of short-interfering RNAs that silence repetitive genetic elements. The 21-nucleotide small RNAs were primarily derived from inverted repeats, including a novel microRNA family that is conserved among the three species, and several gene families, including Crinkler effectors and type III fibronectins. The Phytophthora microRNA is predicted to target a family of amino acid/auxin permeases, and we propose that 21-nucleotide small RNAs function at the post-transcriptional level. The functional significance of microRNA-guided regulation of amino acid/auxin permeases and the association of 21-nucleotide small RNAs with Crinkler effectors remains unclear, but this work provides a framework for testing the role of small RNAs in Phytophthora biology and pathogenesis in future work.

  7. Phytophthora have distinct endogenous small RNA populations that include short interfering and microRNAs.

    Science.gov (United States)

    Fahlgren, Noah; Bollmann, Stephanie R; Kasschau, Kristin D; Cuperus, Josh T; Press, Caroline M; Sullivan, Christopher M; Chapman, Elisabeth J; Hoyer, J Steen; Gilbert, Kerrigan B; Grünwald, Niklaus J; Carrington, James C

    2013-01-01

    In eukaryotes, RNA silencing pathways utilize 20-30-nucleotide small RNAs to regulate gene expression, specify and maintain chromatin structure, and repress viruses and mobile genetic elements. RNA silencing was likely present in the common ancestor of modern eukaryotes, but most research has focused on plant and animal RNA silencing systems. Phytophthora species belong to a phylogenetically distinct group of economically important plant pathogens that cause billions of dollars in yield losses annually as well as ecologically devastating outbreaks. We analyzed the small RNA-generating components of the genomes of P. infestans, P. sojae and P. ramorum using bioinformatics, genetic, phylogenetic and high-throughput sequencing-based methods. Each species produces two distinct populations of small RNAs that are predominantly 21- or 25-nucleotides long. The 25-nucleotide small RNAs were primarily derived from loci encoding transposable elements and we propose that these small RNAs define a pathway of short-interfering RNAs that silence repetitive genetic elements. The 21-nucleotide small RNAs were primarily derived from inverted repeats, including a novel microRNA family that is conserved among the three species, and several gene families, including Crinkler effectors and type III fibronectins. The Phytophthora microRNA is predicted to target a family of amino acid/auxin permeases, and we propose that 21-nucleotide small RNAs function at the post-transcriptional level. The functional significance of microRNA-guided regulation of amino acid/auxin permeases and the association of 21-nucleotide small RNAs with Crinkler effectors remains unclear, but this work provides a framework for testing the role of small RNAs in Phytophthora biology and pathogenesis in future work.

  8. Evidence for homoploid speciation in Phytophthora alni supports taxonomic reclassification in this species complex.

    Science.gov (United States)

    Husson, C; Aguayo, J; Revellin, C; Frey, P; Ioos, R; Marçais, B

    2015-04-01

    Alder decline has been a problem along European watercourses since the early 1990s. Hybridization was identified as the main cause of this emerging disease. Indeed, the causal agent, a soil-borne pathogen named Phytophthora alni subsp. alni (Paa) is the result of interspecific hybridization between two taxa, Phytophthora alni subsp. multiformis (Pam) and Phytophthora alni subsp. uniformis (Pau), initially identified as subspecies of Paa. The aim of this work was to characterize the ploidy level within the P. alni complex that is presently poorly understood. For that, we used two complementary approaches for a set of 31 isolates of Paa, Pam and Pau: (i) quantification of allele copy number of three single-copy nuclear genes using allele-specific real-time PCR and (ii) comparison of the genome size estimated by flow cytometry. Relative quantification of alleles of the three single-copy genes showed that the copy number of a given allele in Paa was systematically half that of its parents Pau or Pam. Moreover, DNA content estimated by flow cytometry in Paa was equal to half the sum of those in Pam and Pau. Our results therefore suggest that the hybrid Paa is an allotriploid species, containing half of the genome of each of its parents Pam and Pau, which in turn are considered to be allotetraploid and diploid, respectively. Paa thus results from a homoploid speciation process. Based on published data and on results from this study, a new formal taxonomic name is proposed for the three taxa Paa, Pam and Pau which are raised to species status and renamed P. ×alni, P. ×multiformis and P. uniformis, respectively. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Phytophthora Have Distinct Endogenous Small RNA Populations That Include Short Interfering and microRNAs

    Science.gov (United States)

    Fahlgren, Noah; Bollmann, Stephanie R.; Kasschau, Kristin D.; Cuperus, Josh T.; Press, Caroline M.; Sullivan, Christopher M.; Chapman, Elisabeth J.; Hoyer, J. Steen; Gilbert, Kerrigan B.; Grünwald, Niklaus J.; Carrington, James C.

    2013-01-01

    In eukaryotes, RNA silencing pathways utilize 20-30-nucleotide small RNAs to regulate gene expression, specify and maintain chromatin structure, and repress viruses and mobile genetic elements. RNA silencing was likely present in the common ancestor of modern eukaryotes, but most research has focused on plant and animal RNA silencing systems. Phytophthora species belong to a phylogenetically distinct group of economically important plant pathogens that cause billions of dollars in yield losses annually as well as ecologically devastating outbreaks. We analyzed the small RNA-generating components of the genomes of P. infestans, P. sojae and P. ramorum using bioinformatics, genetic, phylogenetic and high-throughput sequencing-based methods. Each species produces two distinct populations of small RNAs that are predominantly 21- or 25-nucleotides long. The 25-nucleotide small RNAs were primarily derived from loci encoding transposable elements and we propose that these small RNAs define a pathway of short-interfering RNAs that silence repetitive genetic elements. The 21-nucleotide small RNAs were primarily derived from inverted repeats, including a novel microRNA family that is conserved among the three species, and several gene families, including Crinkler effectors and type III fibronectins. The Phytophthora microRNA is predicted to target a family of amino acid/auxin permeases, and we propose that 21-nucleotide small RNAs function at the post-transcriptional level. The functional significance of microRNA-guided regulation of amino acid/auxin permeases and the association of 21-nucleotide small RNAs with Crinkler effectors remains unclear, but this work provides a framework for testing the role of small RNAs in Phytophthora biology and pathogenesis in future work. PMID:24204767

  10. Intracellular and extracellular phosphatidylinositol 3-phosphate produced by Phytophthora species is important for infection.

    Science.gov (United States)

    Lu, Shan; Chen, Linlin; Tao, Kai; Sun, Nannan; Wu, Yuren; Lu, Xiaoxue; Wang, Yuanchao; Dou, Daolong

    2013-09-01

    RxLR effectors produced by Phytophthora pathogens have been proposed to bind to phosphatidylinositol 3-phosphate (PtdIns(3)P) to mediate their translocation into host cells and/or to increase their stability in planta. Since the levels of PtdIns(3)P in plants are low, we examined whether Phytophthora species may produce PtdIns(3)P to promote infection. We observed that PtdIns(3)P-specific GFP biosensors could bind to P. parasitica and P. sojae hyphae during infection of Nicotiana benthamiana leaves transiently secreting the biosensors, suggesting that the hyphae exposed PtdIns(3)P on their plasma membrane and/or secreted PtdIns(3)P. Silencing of the phosphatidylinositol 3-kinases (PI3K) genes, treatment with LY294002, or expression of PtdIns(3)P-binding proteins by P. sojae reduced the virulence of the pathogen on soybean, indicating that pathogen-synthesized PtdIns(3)P was required for full virulence. Secretion of PtdIns(3)P-binding proteins or of a PI3P-5-kinase by N. benthamiana leaves significantly increased the level of resistance to infection by P. parasitica and P. capsici. Together, our results support the hypothesis that Phytophthora species produce external PtdIns(3)P to aid in infection, such as to promote entry of RxLR effectors into host cells. Our results derived from P. sojae RxLR effector Avr1b confirm that both the N-terminus and the C-terminus of this effector can bind PtdIns(3)P.

  11. Influence of electron beam irradiation on growth of Phytophthora cinnamomi and its control in substrates

    International Nuclear Information System (INIS)

    MigdaŁ, Wojciech; Orlikowski, Leszek B.; Ptaszek, Magdalena; Gryczka, Urszula

    2012-01-01

    Very extensive production procedure, especially in plants growing under covering, require methods, which would allow quick elimination or substantial reduction of populations of specific pathogens without affecting the growth and development of the cultivated plants. Among soil-borne pathogens, the Phytophthora species are especially dangerous for horticultural plants. In this study, irradiation with electron beam was applied to control Phytophthora cinnamomi. The influence of irradiation dose on the reduction of in vitro growth and the population density of the pathogen in treated peat and its mixture with composted pine bark (1:1), as well as the health of Chamaecyparis lawsoniana and Lavandula angustifolia plants were evaluated. Application of irradiation at a dose of 1.5 kGy completely inhibited the in vitro development of P. cinnamomi. This irradiation effect was connected with the disintegration of the hyphae and spores of the species. Irradiation of peat and its mixture with composted pine bark with 10 kGy resulted in the inhibition of stem base rot development in Ch. lawsoniana. Symptoms of the disease were not observed when the substrates were treated with 15 kGy. In the case of L. angustifolia, stem root rot was not observed on cuttings transplanted to infected peat irradiated at a dose of 10 kGy. Irradiation of the horticultural substrates did not affect plant growth. - Highlights: ► Electron beam irradiation is effective against soil-borne pathogens. ► Application of irradiation at dose 1.5 kGy completely inhibited in vitro development of Phytophthora cinnamomi. ► Irradiation of horticultural substrata did not influence the growth of plants.

  12. NAPUS 2000 Rapeseed (Brassica napus breeding for improved human nutrition

    Directory of Open Access Journals (Sweden)

    Friedt Wolfgang

    2001-01-01

    Full Text Available Following a competition announcement of the Federal Ministry of Research and Education (BMBF a project dealing with the improvement of the nutritional value of oilseed rape (Brassica napus for food applications and human nutrition was worked out and started in autumn 1999. A number of partners (Figure 2 are carrying out a complex project reaching from the discovery, characterisation, isolation and transfer of genes of interest up to breeding of well performing varieties combined with important agronomic traits. Economic studies and processing trials as well as nutritional investigations of the new qualities are undertaken. B. napus seed quality aspects with respect to seed coat colour, oil composition, lecithin and protein fractions and antioxidants like tocopherols and resveratrol will be improved.

  13. Hormones and Pod Development in Oilseed Rape (Brassica napus) 1

    Science.gov (United States)

    de Bouille, Pierre; Sotta, Bruno; Miginiac, Emile; Merrien, André

    1989-01-01

    The endogenous levels of several plant growth substances (indole acetic acid, IAA; abscisic acid, ABA; zeatin, Z; zeatin riboside, [9R]Z; isopentenyladenine, iP; and isopentenyladenosine, [9R]iP were measured during pod development of field grown oilseed Rape (Brassica napus L. var oleifera cv Bienvenu) with high performance liquid chromatography and immunoenzymic (enzyme-linked immunosorbent assay, ELISA) techniques. Results show that pod development is characterized by high levels of Z and [9R]Z in 3 day old fruits and of IAA on the fourth day. During pod maturation, initially a significant increase of IAA and cytokinins was observed, followed by a progressive rise of ABA levels and a concomitant decline of IAA and cytokinin (except iP) levels. The relationship between hormone levels and development, especially pod number, seed number per pod, and seed weight determination, will be discussed. PMID:16666891

  14. EFFECTS OF PLANT NUTRITION ON CANOLA (Brassica napus L. GROWTH

    Directory of Open Access Journals (Sweden)

    Sami Süzer

    2016-03-01

    Full Text Available Canola (Brassica napus L. is an important edible oilseed crop in the World and in Turkey. It has a healthy vegetable oil because of its balance with omega 3-6-9 essential fatty acids, making canola oil a healthy vegetable oil throughout the World for cooking and processed food industry. Canola production of high yield and good quality usually depends on well-balanced plant nutrition and growing conditions. A well-balanced soil condition also affects canola plants responses to stress factors such as disease and bad weather conditions. Nitrogen, phosphorus and potassium (NPK are some of the major nutrients required to significantly increase canola yield. Fertilizer application dosages in canola production vary because of the variable occurrence of NPK in the soil. A high yielding canola production needs a well-balanced fertilization program.

  15. Effects of gamma radiation in cauliflower (Brassica spp) minimally processed

    International Nuclear Information System (INIS)

    Nunes, Thaise C.F.; Rogovschi, Vladimir D.; Thomaz, Fernanda S.; Trindade, Reginaldo A.; Villavicencio, Anna L.C.H.; Alencar, Severino M.

    2007-01-01

    Consumers demand for health interests and the latest diet trends. The consumption of vegetables worldwide has increased every year over the past decade, consequently, less extreme treatments or additives are being required. Minimally processed foods have fresh-like characteristics and satisfy the new consumer demand. Food irradiation is an exposure process of the product to controlled sources of gamma radiation with the intention to destroy pathogens and to extend the shelf life. Minimally processed cauliflower (Brassica oleraceae) exposed to low dose of gamma radiation does not show any change in sensory attributes. The aim of this study was to analyze the effects of the low doses of gamma radiation on sensorial aspects like appearance, texture and flavor of minimally processed cauliflower. (author)

  16. Efficiency of wheat brassica mixtures with different seed rates in rainfed areas of potohar-pakistan

    International Nuclear Information System (INIS)

    Khan, S.; Khan, M.A.; Akmal, M.; Jabeen, A.

    2014-01-01

    Mixed over sole cropping is advantageous under the rainfed conditions in Pakistan. This avoids risk of complete crop failure and may returns higher income. The study aimed to investigate appropriate seed-rates combination for wheat-Brassica as mixed- or intercropped in rainfed conditions. Experiments were conducted at National Agricultural Research Center (NARC), Islamabad Pakistan during winter 2004-05 and 2005-06 using 10 treatments for wheat and Brassica as sole and mixed- or intercropped with 100 and 5 kg ha/sup -1/ for sole crop and 100 kg ha/sup -1/ for wheat with 40, 50, 60, and 70% lower than the recommended for Brassica. Sowing was done in 3rd week of October each year, in lines spaced 30cm. Fertilizer was applied N 48, P/sub 2/O/sub 5/ 34 and K/sub 2/O 18 (kg ha/sup -1/). Brassica was manually removed for fodder at flowering. Seed rate (SR) significantly (p<0.05) affected wheat grain yield. Cropping system (CS) significantly (p<0.05) affected grain yield of Brassica. Interactions of CS and SR were also significant (p<0.05) for both species. Planned mean comparison for grain yield was found significant (p<0.05) for wheat and brassica. Grain yield for sole wheat was 4.28t ha/sup -1/ but reported higher in mixed than intercropped. Grain yield of wheat decreased with increase in seed rate of Brassica as intercropped. Higher grain yield (4.39 t ha/sup -1/) of wheat was recorded for seed rates combinations 100:50 (%) as wheat: Brassica intercropped. The land equivalent ratio (LER) for mixed or intercropped system was higher than the sole crop and it increased with increase in the seed rate of Brassica as mixed crop but decreased as intercropped. The high LER was associated to treatment 100:50 (%) seed rates combination for wheat:Brassica as intercropped. Intercropped resulted the greater LER (1.78) than the mixed crop (1.66) and was found most effective for sustainable production in the rainfed areas for a higher net return. (author)

  17. Quantification of Plasmodiophora brassicae Using a DNA-Based Soil Test Facilitates Sustainable Oilseed Rape Production.

    Science.gov (United States)

    Wallenhammar, Ann-Charlotte; Gunnarson, Albin; Hansson, Fredrik; Jonsson, Anders

    2016-04-22

    Outbreaks of clubroot disease caused by the soil-borne obligate parasite Plasmodiophora brassicae are common in oilseed rape (OSR) in Sweden. A DNA-based soil testing service that identifies fields where P. brassicae poses a significant risk of clubroot infection is now commercially available. It was applied here in field surveys to monitor the prevalence of P. brassicae DNA in field soils intended for winter OSR production and winter OSR field experiments. In 2013 in Scania, prior to planting, P. brassicae DNA was detected in 60% of 45 fields on 10 of 18 farms. In 2014, P. brassicae DNA was detected in 44% of 59 fields in 14 of 36 farms, in the main winter OSR producing region in southern Sweden. P. brassicae was present indicative of a risk for >10% yield loss with susceptible cultivars (>1300 DNA copies g soil(-1)) in 47% and 44% of fields in 2013 and 2014 respectively. Furthermore, P. brassicae DNA was indicative of sites at risk of complete crop failure if susceptible cultivars were grown (>50 000 copies g(-1) soil) in 14% and 8% of fields in 2013 and 2014, respectively. A survey of all fields at Lanna research station in western Sweden showed that P. brassicae was spread throughout the farm, as only three of the fields (20%) showed infection levels below the detection limit for P.brassicae DNA, while the level was >50,000 DNA copies g(-1) soil in 20% of the fields. Soil-borne spread is of critical importance and soil scraped off footwear showed levels of up to 682 million spores g(-1) soil. Soil testing is an important tool for determining the presence of P. brassicae and providing an indication of potential yield loss, e.g., in advisory work on planning for a sustainable OSR crop rotation. This soil test is gaining acceptance as a tool that increases the likelihood of success in precision agriculture and in applied research conducted in commercial oilseed fields and at research stations. The present application highlights the importance of prevention of

  18. Quantification of Plasmodiophora brassicae Using a DNA-Based Soil Test Facilitates Sustainable Oilseed Rape Production

    Directory of Open Access Journals (Sweden)

    Ann-Charlotte Wallenhammar

    2016-04-01

    Full Text Available Outbreaks of clubroot disease caused by the soil-borne obligate parasite Plasmodiophora brassicae are common in oilseed rape (OSR in Sweden. A DNA-based soil testing service that identifies fields where P. brassicae poses a significant risk of clubroot infection is now commercially available. It was applied here in field surveys to monitor the prevalence of P. brassicae DNA in field soils intended for winter OSR production and winter OSR field experiments. In 2013 in Scania, prior to planting, P. brassicae DNA was detected in 60% of 45 fields on 10 of 18 farms. In 2014, P. brassicae DNA was detected in 44% of 59 fields in 14 of 36 farms, in the main winter OSR producing region in southern Sweden. P. brassicae was present indicative of a risk for >10% yield loss with susceptible cultivars (>1300 DNA copies g soil−1 in 47% and 44% of fields in 2013 and 2014 respectively. Furthermore, P. brassicae DNA was indicative of sites at risk of complete crop failure if susceptible cultivars were grown (>50 000 copies g−1 soil in 14% and 8% of fields in 2013 and 2014, respectively. A survey of all fields at Lanna research station in western Sweden showed that P. brassicae was spread throughout the farm, as only three of the fields (20% showed infection levels below the detection limit for P.brassicae DNA, while the level was >50,000 DNA copies g−1 soil in 20% of the fields. Soil-borne spread is of critical importance and soil scraped off footwear showed levels of up to 682 million spores g−1 soil. Soil testing is an important tool for determining the presence of P. brassicae and providing an indication of potential yield loss, e.g., in advisory work on planning for a sustainable OSR crop rotation. This soil test is gaining acceptance as a tool that increases the likelihood of success in precision agriculture and in applied research conducted in commercial oilseed fields and at research stations. The present application highlights the importance of

  19. New record of Phytophthora root and stem rot of Lavandula angustifolia

    Directory of Open Access Journals (Sweden)

    Leszek B. Orlikowski

    2013-12-01

    Full Text Available Phytophthora cinnamomi was isolated from rotted root and stem parts of lavender as well as from soil taken from containers with diseased plants. Additionally Botrytis cinerea, Fusarium spp. and Sclerotinia sclerotiorum were often isolated from diseased tissues. P. cinnamomi colonised leaves and stem parts of 4 lavender species in laboratory trials and caused stem rot of plants in greenhouse experiments. Cardinal temperature for in vitro growth were about 7,5 and 32°C with optimum 25-27,5°C. The species colonised stem tissues at temperature ranged from 10° to 32°C.

  20. Proton activation studies of changes in mineral composition of Eucalyptus obliqua due to Phytophthora cinnamomi

    International Nuclear Information System (INIS)

    Chaudhri, M.A.; Lee, M.M.; Rouse, J.L.; Weste, G.

    1978-01-01

    As part of a study of disease caused by Phytophthora cinnamomi in native vegetation, the mineral composition of diseased plants has been compared with those free from disease, but grown under the same conditions. Using proton activation it has been shown that a reduction of 70% in iron and 41% in titanium occurs for diseased Eucalytus obliqua compared with disease-free plants. The reduction in iron is associated with severe chlorosis which occurs as a primary symptom in most plants attacked by this pathogen. (author)

  1. Genetic Diversity and Origins of the Homoploid-Type Hybrid Phytophthora ×alni.

    Science.gov (United States)

    Aguayo, Jaime; Halkett, Fabien; Husson, Claude; Nagy, Zoltán Á; Szigethy, András; Bakonyi, József; Frey, Pascal; Marçais, Benoit

    2016-12-15

    Assessing the process that gives rise to hybrid pathogens is central to understanding the evolution of emerging plant diseases. Phytophthora ×alni, a pathogen of alder, results from the homoploid hybridization of two related species, Phytophthora uniformis and Phytophthora ×multiformis Describing the genetic characteristics of P ×alni should help us understand how reproductive mechanisms and historical processes shaped the population structure of this emerging hybrid pathogen. The population genetic structure of P ×alni and the relationship with its parental species were investigated using 12 microsatellites and one mitochondrial DNA (mtDNA) marker on a European collection of 379 isolates. Populations of P ×alni were dominated by one multilocus genotype (MLG). The frequency of this dominant MLG increased after the disease emergence together with a decline in diversity, suggesting that it was favored by a genetic mechanism such as drift or selection. Combined microsatellite and mtDNA results confirmed that P ×alni originated from multiple hybridization events that involved different genotypes of the progenitors. Our detailed analyses point to a geographic structure that mirrors that observed for P. uniformis in Europe. The study provides more insights on the contribution of P. uniformis, an invasive species in Europe, to the emergence of Phytophthora-induced alder decline. Our study describes an original approach to assess the population genetics of polyploid organisms using microsatellite markers. By studying the parental subgenomes present in the interspecific hybrid P. ×alni, we were able to assess the geographical and temporal structure of European populations of the hybrid, shedding new light on the evolution of an emerging plant pathogen. In turn, the study of the parental subgenomes permitted us to assess some genetic characteristics of the parental species of P. ×alni, P. uniformis, and P ×multiformis, which are seldom sampled in nature. The

  2. PIXE studies of changes in mineral composition of plants infected with Phytophthora cinnamomi

    Science.gov (United States)

    Chaudhri, M. Anwar; Papper, C. S.; Weste, G.

    1981-03-01

    The mineral composition of susceptible and resistant plants from native forests infected with Phytophthora cinnamomi was compared between themselves and with the same species from disease-free areas. Root and shoot samples from different plants were carefully ashed, compressed into pellets and analysed with the thick target PIXE technique. A number of elements, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Sn and Pb, were detected. Many of the elements showed variations, sometimes large, between the composition of susceptible and resistant plants, and between the same species from infected and disease-free forests.

  3. Propuesta de medio de cultivo para el estudio de Phytophthora Nicotianae Breda de Haan

    OpenAIRE

    Vaillant Flores, Daymara I; González García, Marleny; Ramírez Ochoa, Rebeca

    2013-01-01

    El género Phytophthora representa un grupo difícil de aislar y conservar. Por lo que se han desarrollado varios medios de cultivo para su estudio. Se propone al medio Agar-tabaco como alternativa para el crecimiento y desarrollo de P. nicotianae. Para realizar este trabajo se emplearon dos cepas: Pp1 y Pp6 aislados de tabaco y piña respectivamente. Ambas se sembraron en discos en agar-tabaco, y se comparó con agar tomate y agar harina de maíz. Se determinó el crecimiento lineal del hongo, las...

  4. PIXE studies of changes in mineral composition of plants infected with Phytophthora cinnamomi

    International Nuclear Information System (INIS)

    Chaudhri, M.A.; Melbourne Univ., Austin; Weste, G.; Papper, C.S.

    1981-01-01

    The mineral composition of susceptible and resistant plants from native forests infected with Phytophthora cinnamomi was compared between themselves and with the same species from disease-free areas. Root and shoot samples from different plants were carefully ashed, compressed into pellets and analysed with the thick target PIXE technique. A number of elements, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Sn, and Pb, were detected. Many of the elements showed variations, sometimes large, between the composition of suspectible and resistant plants, and between the same species from infected and disease-free forests. (orig.)

  5. Identification of stable resistance to Phytophthora infestans in potato genotypes evaluated in field experiments in Peru

    DEFF Research Database (Denmark)

    Wulff, Ednar Gadelha; Pérez, W.; Nelson, R.J.

    2007-01-01

    Abstract: In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non......-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans...

  6. Challenges and Strategies for Breeding Resistance in Capsicum annuum to the Multifarious Pathogen, Phytophthora capsici

    Directory of Open Access Journals (Sweden)

    Derek W. Barchenger

    2018-05-01

    Full Text Available Phytophthora capsici is the most devastating pathogen for chile pepper production worldwide and current management strategies are not effective. The population structure of the pathogen is highly variable and few sources of widely applicable host resistance have been identified. Recent genomic advancements in the host and the pathogen provide important insights into the difficulties reported by epidemiological and physiological studies published over the past century. This review highlights important challenges unique to this complex pathosystem and suggests strategies for resistance breeding to help limit losses associated with P. capsici.

  7. Growth and "1"3"7Cs uptake and accumulation among 56 Japanese cultivars of Brassica rapa, Brassica juncea and Brassica napus grown in a contaminated field in Fukushima: Effect of inoculation with a Bacillus pumilus strain

    International Nuclear Information System (INIS)

    Djedidi, Salem; Kojima, Katsuhiro; Ohkama-Ohtsu, Naoko; Bellingrath-Kimura, Sonoko Dorothea; Yokoyama, Tadashi

    2016-01-01

    Fifty six local Japanese cultivars of Brassica rapa (40 cultivars), Brassica juncea (10 cultivars) and Brassica napus (6 cultivars) were assessed for variability in growth and "1"3"7Cs uptake and accumulation in association with a Bacillus pumilus strain. Field trial was conducted at a contaminated farmland in Nihonmatsu city, in Fukushima prefecture. Inoculation resulted in different responses of the cultivars in terms of growth and radiocesium uptake and accumulation. B. pumilus induced a significant increase in shoot dry weight in 12 cultivars that reached up to 40% in one B. rapa and three B. juncea cultivars. Differences in radiocesium uptake were observed between the cultivars of each Brassica species. Generally, inoculation resulted in a significant increase in "1"3"7Cs uptake in 22 cultivars, while in seven cultivars it was significantly decreased. Regardless of plant cultivar and bacterial inoculation, the transfer of "1"3"7Cs to the plant shoots (TF) varied by a factor of up to 5 and it ranged from to 0.011 to 0.054. Five inoculated cultivars, showed enhanced shoot dry weights and decreased "1"3"7Cs accumulations, among which two B. rapa cultivars named Bitamina and Nozawana had a significantly decreased "1"3"7Cs accumulation in their shoots. Such cultivars could be utilized to minimize the entry of radiocesium into the food chain; however, verifying the consistency of their radiocesium accumulation in other soils is strongly required. Moreover, the variations in growth and radiocesium accumulation, as influenced by Bacillus inoculation, could help selecting well grown inoculated Brassica cultivars with low radiocesium accumulation in their shoots. - Highlights: • Out of 56 Brassica cultivars, inoculation significantly increased shoot dry weight in 12 cultivars. • Inoculation triggered a significant increase and decrease in "1"3"7Cs uptake, respectively in 22 and 7 cultivars. • Five cultivars had an enhanced shoot dry weight and decreased "1"3"7Cs

  8. Wybrane zagadnienia z biologii grzyba Plasmodiophora brassicae Wor. [Some problems in the life-cycle of fungus Plasmodiophora brassicae, Wor.

    Directory of Open Access Journals (Sweden)

    B. Nowicki

    2015-06-01

    Full Text Available The quickest loss of infectivity of Plasmodiophora brassicae Wor. resting spores was observed in acid soil. Jnlectivity was ratained longer in neutral and alkaline soils. The infection of cabbage seedlings took place in a broad pH range from 3.3 to 8.1, the optimum soil pH for infection being at 5.3 - 5.7. When the number of spores in the soil increased the infection took place in the infection took place in the broader pH range. The plants which were planted as seedlings in infested soil were infected in a broader pH range than plants which were grown from seeds in infested soil.

  9. Molecular mapping of QTL alleles of Brassica oleracea affecting days to flowering and photosensitivity in spring Brassica napus.

    Science.gov (United States)

    Rahman, Habibur; Bennett, Rick A; Kebede, Berisso

    2018-01-01

    Earliness of flowering and maturity are important traits in spring Brassica napus canola-whether grown under long- or short-day condition. By use of a spring B. napus mapping population carrying the genome content of B. oleracea and testing this population under 10 to 18 h photoperiod and 18 to 20 0C (day) temperature conditions, we identified a major QTL on the chromosome C1 affecting flowering time without being influenced by photoperiod and temperature, and a major QTL on C9 affecting flowering time under a short photoperiod (10 h); in both cases, the QTL alleles reducing the number of days to flowering in B. napus were introgressed from the late flowering species B. oleracea. Additive effect of the C1 QTL allele at 14 to18 h photoperiod was 1.1 to 2.9 days; however, the same QTL allele exerted an additive effect of 6.2 days at 10 h photoperiod. Additive effect of the C9 QTL at 10 h photoperiod was 2.8 days. These two QTL also showed significant interaction in the control of flowering only under a short-day (10 h photoperiod) condition with an effect of 2.3 days. A few additional QTL were also detected on the chromosomes C2 and C8; however, none of these QTL could be detected under all photoperiod and temperature conditions. BLASTn search identified several putative flowering time genes on the chromosomes C1 and C9 and located the physical position of the QTL markers in the Brassica genome; however, only a few of these genes were found within the QTL region. Thus, the molecular markers and the genomic regions identified in this research could potentially be used in breeding for the development of early flowering photoinsensitive B. napus canola cultivars, as well as for identification of candidate genes involved in flowering time variation and photosensitivity.

  10. Comparative Analysis of Disease-Linked Single Nucleotide Polymorphic Markers from Brassica rapa for Their Applicability to Brassica oleracea

    Science.gov (United States)

    Cho, Young-Il; Ahn, Yul-Kyun; Tripathi, Swati; Kim, Jeong-Ho; Lee, Hye-Eun; Kim, Do-Sun

    2015-01-01

    Numerous studies using single nucleotide polymorphisms (SNPs) have been conducted in humans, and other animals, and in major crops, including rice, soybean, and Chinese cabbage. However, the number of SNP studies in cabbage is limited. In this present study, we evaluated whether 7,645 SNPs previously identified as molecular markers linked to disease resistance in the Brassica rapa genome could be applied to B. oleracea. In a BLAST analysis using the SNP sequences of B. rapa and B. oleracea genomic sequence data registered in the NCBI database, 256 genes for which SNPs had been identified in B. rapa were found in B. oleracea. These genes were classified into three functional groups: molecular function (64 genes), biological process (96 genes), and cellular component (96 genes). A total of 693 SNP markers, including 145 SNP markers [BRH—developed from the B. rapa genome for high-resolution melt (HRM) analysis], 425 SNP markers (BRP—based on the B. rapa genome that could be applied to B. oleracea), and 123 new SNP markers (BRS—derived from BRP and designed for HRM analysis), were investigated for their ability to amplify sequences from cabbage genomic DNA. In total, 425 of the SNP markers (BRP-based on B. rapa genome), selected from 7,645 SNPs, were successfully applied to B. oleracea. Using PCR, 108 of 145 BRH (74.5%), 415 of 425 BRP (97.6%), and 118 of 123 BRS (95.9%) showed amplification, suggesting that it is possible to apply SNP markers developed based on the B. rapa genome to B. oleracea. These results provide valuable information that can be utilized in cabbage genetics and breeding programs using molecular markers derived from other Brassica species. PMID:25790283

  11. Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group) through Embryo Rescue

    Science.gov (United States)

    Sharma, Brij B.; Kalia, Pritam; Singh, Dinesh; Sharma, Tilak R.

    2017-01-01

    Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is a very important disease of cauliflower (Brassica oleracea botrytis group) resulting into 10–50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome), therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s) for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B1) were generated between cauliflower “Pusa Sharad” and Ethiopian mustard “NPC-9” employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC) primers. Meiosis in the di-genomic (BCC) interspecific hybrid of B. oleracea botrytis group (2n = 18, CC) × B. carinata (2n = 4x = 34, BBCC) was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F1 hybrid and BC1 plants. The F1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC1 population. This effort will go a long way in pyramiding gene(s) for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides. PMID:28769959

  12. Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group through Embryo Rescue

    Directory of Open Access Journals (Sweden)

    Brij B. Sharma

    2017-07-01

    Full Text Available Black rot caused by Xanthomonas campestris pv. campestris (Xcc is a very important disease of cauliflower (Brassica oleracea botrytis group resulting into 10–50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome, therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B1 were generated between cauliflower “Pusa Sharad” and Ethiopian mustard “NPC-9” employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC primers. Meiosis in the di-genomic (BCC interspecific hybrid of B. oleracea botrytis group (2n = 18, CC × B. carinata (2n = 4x = 34, BBCC was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F1 hybrid and BC1 plants. The F1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC1 population. This effort will go a long way in pyramiding gene(s for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides.

  13. Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group) through Embryo Rescue.

    Science.gov (United States)

    Sharma, Brij B; Kalia, Pritam; Singh, Dinesh; Sharma, Tilak R

    2017-01-01

    Black rot caused by Xanthomonas campestris pv. campestris ( Xcc ) is a very important disease of cauliflower ( Brassica oleracea botrytis group) resulting into 10-50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome), therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s) for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B 1 ) were generated between cauliflower "Pusa Sharad" and Ethiopian mustard "NPC-9" employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F 1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC) primers. Meiosis in the di-genomic (BCC) interspecific hybrid of B. oleracea botrytis group (2 n = 18, CC) × B. carinata (2 n = 4x = 34, BBCC) was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2 n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F 1 hybrid and BC 1 plants. The F 1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC 1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC 1 population. This effort will go a long way in pyramiding gene(s) for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides.

  14. Effect of environmental conditions and lesion age on sporulation of Phytophthora ramorum on California bay laurel, rhododendron, and camellia

    Science.gov (United States)

    Steve Tjosvold; David Chambers; Sylvia Mori

    2013-01-01

    The objective of our research was to determine the environmental conditions and lesion age favorable for Phytophthora ramorum sporulation under field conditions. For 2 years, new camellia, rhododendron, and California bay laurel (Umbellaria californica (Hook. & Arn.) Nutt.) nursery stock were seasonally inoculated (every 3 months) on foliage....

  15. Soil moisture and temperature conditions affect survival and sporulation capacity of Rhododendron leaf disks infested with Phytophthora ramorum

    Science.gov (United States)

    Ebba K. Peterson; Niklaus J. Grünwald; Jennifer L. ParkeSoil

    2017-01-01

    Soilborne inoculum (infested leaf debris which has become incorporated into the soil) may be an important contributor to the persistence of the sudden oak death pathogen Phytophthora ramorum in recurrently positive nurseries. To initiate new epidemics, soilborne inoculum must not only be able to survive over time, but also be capable of...

  16. Single-strand conformation polymorphism analysis of ribosomal DNA for detection of Phytophthora ramorum directly from plant tissues

    Science.gov (United States)

    Ping Kong; Patricia A. Richardson; Chuanxue Hong; Thomas L. Kubisiak

    2006-01-01

    At the first Sudden Oak Death Science Symposium, we reported on the use of a single strand conformation polymorphism (SSCP) analysis for rapid identification of Phytophthora ramorum in culture. We have since assessed and improved the fingerprinting technique for detecting this pathogen directly from plant tissues. The improved SSCP protocol uses a...

  17. Phytophthora ramorum infection in coast live oaks and Shreve's oaks treated with insecticide to prevent beetle colonization

    Science.gov (United States)

    Brice A. McPherson; David L. Wood; David M. Rizzo; Pavel Svihra; Steve Tjosvold; Andrew J. Storer; Richard B. Standiford

    2006-01-01

    As the name implies, sudden oak death, caused by Phytophthora ramorum, kills many, if not most of the coast live oaks, Quercus agrifolia, that become infected (McPherson and others, 2005). Several genera of ambrosia and bark beetles (Coleoptera: Scolytidae) colonize bleeding (infected) trees and are suspected to hasten tree death....

  18. Pathogenicity of Phytophthora austrocedrae on Austrocedrus chilensis and its relation with mal del ciprés in Patagonia

    Science.gov (United States)

    A. G. Greslebin; E. M. Hansen

    2010-01-01

    Field observations, isolations and pathogenicity tests were performed on Austrocedrus chilensis (Cupressaceae) trees to determine the pathogenicity of Phytophthora austrocedrae and its role in the aetiology of the cypress disease mal del ciprés (MDC) in Argentina. It was found that P. austrocedrae...

  19. IUFRO Fourth Meeting of Working Party 7.02.09, Phytophthoras in Forest and Natural Ecosystems: Meeting Summary

    Science.gov (United States)

    Susan Frankel

    2009-01-01

    On behalf of the Fourth Phytophthoras in Forest and Natural Ecosystems local organizing committee and co-chairs Everett Hansen, Clive Brasier, and Giles Hardy, I thank you for your contributions to this Working Party meeting. The past week has stimulated much thought and discussion, thanks to the 100 participants from 15 countries, 48 papers and 31 posters, two field...

  20. Genetic diversity of Phytophthora infestans sensu lato in Ecuador provides new insight into the origin of this important plant pathogen

    NARCIS (Netherlands)

    Adler, N.E.; Erselius, L.J.; Chacón, G.M.; Flier, W.G.; Ordonez, M.E.; Kroon, L.P.N.M.; Forbes, G.A.

    2004-01-01

    The metapopulation structure of Phytophthora infestans sensu lato is genetically diverse in the highlands of Ecuador. Previous reports documented the diversity associated with four putative clonal lineages of the pathogen collected from various hosts in the genus Solanum. This paper simultaneously