scholarly journals Peronospora arborescens Causes Downy Mildew Disease in Commercial Opium Poppy Crops in France

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 834-834 ◽  
Author(s):  
M. Montes-Borrego ◽  
F. J. Muñoz-Ledesma ◽  
R. M. Jiménez-Díaz ◽  
B. B. Landa
Keyword(s):  
Downy Mildew ◽  
Phylogenetic Analyses ◽  
Opium Poppy ◽  
Its Sequences ◽  
Maximum Parsimony Analysis ◽  
Disease Symptoms ◽  
Specific Pcr ◽  
Three Samples ◽  
Species Specific ◽  
Downy Mildew Disease

Opium poppy is a strategic crop for the pharmaceutical industry because it is the only source of morphine, codeine, and thebaine alkaloid drugs. Approximately 7,360 ha (average from 2001 through 2007) of opium poppy (Papaver somniferum) are grown annually in France, mainly in the Northern-East (Champagne-Ardenne) and Centre-West (Centre and Poitou-Charentes) regions of the country. This acreage accounts for nearly 5.6% of the legally cultivated opium poppies worldwide. Disease symptoms resembling those of downy mildew (2) have been observed frequently in those opium-poppy-growing areas, especially in the Charente-Maritime, Cher, Loiret, and Loir et Cher departments. Disease symptoms included chlorotic to light yellow lesions on the leaf blade, curling and thickening of affected tissues, and expanding necrotic lesions that coalesced, eventually giving rise to large necrotic areas or death of the entire leaf tissues and the plant. With wet weather or high relative humidity, sporangiophores with sporangia were produced frequently on the abaxial leaf surface and occasionally on the adaxial side. Peronospora arborescens and P. cristata have been demonstrated as causal agents of opium poppy downy mildew disease and both have been reported in Europe (1–3); however, the specific identity causal agent in commercial opium poppy crops in France has not yet been determined. Microscopic observations of affected leaves in symptomatic opium poppy leaves sampled from three commercial fields in Loiret Department revealed dichotomously branching sporangiophores bearing single sporangia and oospores of shape and measurements similar to those reported for P. arborescens and P. cristata (1,3). Sporangia dimensions of P. arborescens and P. cristata overlapped, making it difficult to differentiate between the two species based solely on morphological characters (3). A species-specific PCR assay protocol (2) that differentiated P. arborescens from P. cristata was used to diagnose the pathogen. Also, the sequence of the complete 5.8S ribosomal DNA gene and internal transcribed spacers (ITS) 1 and 2 were determined and maximum parsimony analysis was performed with the Peronospora spp. data set described by Landa et al. (2). Both species-specific PCR and phylogenetic analyses of ITS sequences showed that P. arborescens was the only Peronospora species associated with the three samples of downy-mildew-affected leaves analyzed. Thus, DNA fragments of 545, 594, and 456 bp were amplified using total DNA extracted from the sampled leaves and P2, P3, and P6 primer pairs (2), respectively. ITS sequences of all three samples showed 100% homology (GenBank Accession No. EU295529). Phylogenetic analyses using Neighbor Joining of those sequences placed the infecting Peronospora sp. in a clade (100% support) that included all P. arborescens sequences from the GenBank database with 99.2 to 99.9% homology among sequences (2,3). To our knowledge, this is the first report and molecular evidence that P. arborescens causes downy mildew disease in commercial opium poppy crops in France. References: (1) S. M. Francis. No. 686 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1981. (2) B. B. Landa et al. Phytopathology 97:1380, 2007. (3) J. B. Scott et al. Phytopathology 93:752, 2003.

scholarly journals Phylogenetic Analysis of Downy Mildew Pathogens of Opium Poppy and PCR-Based In Planta and Seed Detection of Peronospora arborescens

2007 ◽  
Vol 97 (11) ◽  
pp. 1380-1390 ◽  
Author(s):  
Blanca B. Landa ◽  
Miguel Montes-Borrego ◽  
Francisco J. Muñoz-Ledesma ◽  
Rafael M. Jiménez-Díaz
Keyword(s):  
Downy Mildew ◽  
Field Experiments ◽  
Phylogenetic Analyses ◽  
Its Region ◽  
Epidemiological Studies ◽  
Papaver Somniferum ◽  
Opium Poppy ◽  
Recent Common Ancestor ◽  
In Planta ◽  
Commercial Seed

Severe downy mildew diseases of opium poppy (Papaver somniferum) can be caused by Peronospora arborescens and P. cristata, but differentiating between the two pathogens is difficult because they share morphological features and a similar host range. In Spain, where severe epidemics of downy mildew of opium poppy have occurred recently, the pathogen was identified as P. arborescens on the basis of morphological traits. In this current study, sequence homology and phylogenetic analyses of the internal transcribed spacer regions (ITS) of the ribosomal DNA (rDNA) were carried out with DNA from P. arborescens and P. cristata from diverse geographic origins, which suggested that only P. arborescens occurs in cultivated Papaver somniferum in Spain. Moreover, analyses of the rDNA ITS region from 27 samples of downy-mildew-affected tissues from all opium-poppy-growing regions in Spain showed that genetic diversity exists within P. arborescens populations in Spain and that these are phylogenetically distinct from P. cristata. P. cristata instead shares a more recent, common ancestor with a range of Peronospora species that includes those found on host plants that are not members of the Papaveraceae. Species-specific primers and a PCR assay protocol were developed that differentiated P. arborescens and P. cristata and proved useful for the detection of P. arborescens in symptomatic and asymptomatic opium poppy plant parts. Use of these primers demonstrated that P. arborescens can be transmitted in seeds and that commercial seed stocks collected from crops with high incidence of the disease were frequently infected. Field experiments conducted in microplots free from P. arborescens using seed stocks harvested from infected capsules further demonstrated that transmission from seedborne P. arborescens to opium poppy plants can occur. Therefore, the specific-PCR detection protocol developed in this study can be of use for epidemiological studies and diagnosing the pathogen in commercial seed stocks; thus facilitating the sanitary control of the disease and avoidance of the pathogen distribution in seeds.

scholarly journals Short communication: Local infection of opium poppy leaves by Peronospora somniferi sporangia can give rise to systemic infections and seed infection in resistant cultivars

2017 ◽  
Vol 15 (3) ◽  
pp. e10SC01
Author(s):  
Miguel Montes-Borrego ◽  
Francisco J. Muñoz-Ledesma ◽  
Rafael M. Jiménez-Díaz ◽  
Blanca B. Landa
Keyword(s):  
Downy Mildew ◽  
Short Communication ◽  
Opium Poppy ◽  
Local Infection ◽  
Resistance Response ◽  
Disease Symptoms ◽  
Resistant Phenotype ◽  
Systemic Nature ◽  
Systemic Infections ◽  
First Time

Downy mildew (DM) of opium poppy (Papaver somniferum) caused by Peronospora somniferi is one of the most destructive diseases of this crop due to the systemic nature of infection as compared with local infections caused by Peronospora meconopsidis, the other downy mildew pathogen of this crop. We developed an inoculation method using Peronospora somniferi sporangia as inoculum and demonstrated for the first time that local infection of leaves by sporangia give rise to systemic infections in the plant as well as of seeds. Our results also showed that this inoculation protocol was very effective in reproducing disease symptoms and assessing the resistance response to DM in opium poppy genotypes under field conditions. More interestingly, results indicate that up to 100% of seed samples from some genotypes showing a complete (symptomless) resistant phenotype were infected by the pathogen when seeds were analyzed by a P. somniferi-specific nested-PCR protocol. This latter aspect deserves further attention while breeding opium poppy for resistance to P. somniferi.

scholarly journals Molecular Characterization of Meloidogyne hispanica (Nematoda, Meloidogynidae) by Phylogenetic Analysis of Genes Within the rDNA in Meloidogyne spp.

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1104-1110 ◽  
Author(s):  
Blanca B. Landa ◽  
Juan E. Palomares Rius ◽  
Nicola Vovlas ◽  
Regina M. D. G. Carneiro ◽  
Carla M. N. Maleita ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Nematode Species ◽  
Maximum Parsimony Analysis ◽  
Biological Traits ◽  
Root Knot Nematode ◽  
Specific Pcr ◽  
Meloidogyne Spp ◽  
Species Specific ◽  
Prunus Spp

In the past, the distribution of Meloidogyne hispanica, the Seville root-knot nematode, appeared to be restricted to the southern part of Spain and Prunus spp.; however, its distribution has been confirmed to be worldwide because it occurs in all continents (Europe, Africa, Asia, Australia, and North, Central, and South America). Differentiation of M. hispanica from other Meloidogyne spp., mainly M. arenaria, can be very difficult using morphological and biological traits data. These species are quite similar and can be regularly confused in inaccurate taxonomic comparisons. In this study, species-specific polymerase chain reaction (PCR) and phylogenetic analysis of sequences from three ribosomal (r)DNA regions (18S, internal transcribed spacer [ITS]1-5.8S-ITS2, and D2-D3 of 28S) were used to characterize three M. hispanica isolates from different geographical origins (Brazil, Portugal, and Spain). Molecular analyses showed identical sequences for all three isolates for the three rDNA regions. Maximum parsimony analysis of the three rDNA regions and the species-specific PCR demonstrated and supported the differentiation of M. hispanica from M. incognita, M. javanica, and M. arenaria and from all described root-knot nematode species.

Occurrence of Vibrio spp. in Fish and Shellfish Collected from the Swiss Market

2011 ◽  
Vol 74 (8) ◽  
pp. 1345-1347 ◽  
Author(s):  
K. SCHÄRER ◽  
S. SAVIOZ ◽  
N. CERNELA ◽  
G. SAEGESSER ◽  
R. STEPHAN
Keyword(s):  
Microbiological Analysis ◽  
Time Data ◽  
Specific Pcr ◽  
Three Samples ◽  
Genes Encoding ◽  
Thermostable Direct Hemolysin ◽  
A Subunit ◽  
Species Specific ◽  
Fish And Shellfish ◽  
Vibrio Spp

The genus Vibrio includes gram-negative bacteria that inhabit estuarine ecosystems. V. cholerae, V. parahaemolyticus, and V. vulnificus pose a considerable public health threat as agents of sporadic and epidemic foodborne infections associated with the consumption of raw or undercooked contaminated fish or shellfish. In this study, we analyzed 138 fish and shellfish samples collected from the Swiss market (fish fillets [n = 102], bivalves [n = 34], and squid [n = 2]). Microbiological analysis was done according to International Organization for Standardization method 21872-1/21872-2:2007, using thiosulfate citrate bile sucrose agar and chromID Vibrio agar as selective agar. Presumptive-positive colonies on thiosulfate citrate bile sucrose agar or chromID Vibrio agar were picked and were identified by the API 20E and species-specific PCR systems. V. cholerae isolates were tested further by PCR for the presence of the cholera toxin A subunit gene (ctxA). V. parahaemolyticus isolates were tested by PCR for genes encoding for thermostable direct hemolysin (tdh) and TDH-related hemolysin (trh). V. cholerae was isolated from three samples and V. parahaemolyticus from eight samples. None of these strains harbored species-specific virulence factors. Further, V. alginolyticus was isolated from 40 samples, and V. fluvialis was isolated from 1 sample. Our study provides, for the first time, data for the assessment of exposure to Vibrio spp. in raw fish and bivalves consumed in Switzerland.

scholarly journals Effect of different inoculum levels of P. arborescens in disease development and yield losses of opium poppy

2021 ◽  
Vol 16 (2) ◽  
pp. 93-98
Author(s):  
Roop Singh ◽  
Pokhar Rawal ◽  
Irfan Khan
Keyword(s):  
Downy Mildew ◽  
Disease Severity ◽  
Seed Yield ◽  
Opium Poppy ◽  
Yield Losses ◽  
Inoculum Concentration ◽  
Pooled Data ◽  
Cent Disease ◽  
Latex Yield ◽  
Downy Mildew Disease

Downy mildew (DM) caused by Peronospora arborescens is the most alarming disease of opium poppy which hampered the production of opium crop in major growing areas of India. The pooled data taken from Rabi 2016-17 and 2017-18 demonstrated that chemical protected un-inoculated plot had a minimum per cent disease severity (9.83) with maximum dry latex yield (31.25 kg ha-1), seed yield (801.31 kg ha-1) and husk yield (889.66 kg ha-1). However, plots inoculated with Peronospora arborescens at high inoculum density of 9×105 spores ml-1 had considerably higher per cent disease severity (67.00) and minimum dry latex yield (6.94 kg ha-1), seed yield (548.42 kg ha-1) and husk yield (590.86 kg ha-1) with maximum 77.79,31.56 and 33.58 per cent loss as compared to un-inoculated chemical protected plot, respectively. The severity of the downy mildew disease was found to rise in direct conflict with the level of inoculum concentration with significant reduction in dry latex yield, seed yield and husk yield.

scholarly journals First report of Peronospora variabilis causing downy mildew disease in cañahua (Chenopodium pallidicaule) in Bolivia

2021 ◽  
Author(s):  
Oscar Miguel Rollano-Peñaloza ◽  
Valeria D. Palma-Encinas ◽  
Paola M. Nogales-Ascarrunz ◽  
Susanne Widell ◽  
Allan G. Rasmusson ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Nutritional Value ◽  
Large Scale ◽  
Artificial Infection ◽  
Potential Threat ◽  
Disease Symptoms ◽  
Sequence Identification ◽  
Visual Confirmation ◽  
Andean Highlands ◽  
Downy Mildew Disease

Abstract Cañahua (Chenopodium pallidicaule Aellen) is a semi-domesticated grain cultivated in the Andean highlands for millennia. Cañahua seeds have high nutritional value and it has become attractive because of its high resistance to frost, drought and saline soils. In May 2018, cañahua plants showed symptoms of the downy mildew disease caused by Peronospora variabilis which is known to heavily affect its tetraploid-relative quinoa. Besides the typical symptoms in the plant, visual confirmation of P. variabilis reproductive structures by microscopy was achieved. In order to verify the ability of P. variabilis to infect cañahua, an artificial infection in three cañahua varieties was performed. The three cañahua varieties were infected by P. variabilis and developed downy mildew disease symptoms. The pathogen identity was confirmed by PCR and Sanger sequencing of the PvCox2 and PvITS region. DNA sequence identification confirmed that the P. variabilis that usually infects quinoa can also infect cañahua plants. Therefore, cañahua when grown next to quinoa must be carefully watched for downy mildew disease symptoms because P. variabilis can be a potential threat for future large scale cañahua agriculture.

scholarly journals Identity and Pathogenicity of Fungi Associated with Crown and Root Rot of Dryland Winter Wheat in Azerbaijan

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2149-2157
Author(s):  
Göksel Özer ◽  
Timothy C. Paulitz ◽  
Mustafa Imren ◽  
Mehtap Alkan ◽  
Hafiz Muminjanov ◽  
...  
Keyword(s):  
Root Rot ◽  
Phylogenetic Analyses ◽  
Fusarium Culmorum ◽  
Elongation Factor ◽  
Bipolaris Sorokiniana ◽  
Specific Pcr ◽  
Wide Range ◽  
Comprehensive Survey ◽  
Crown And Root Rot ◽  
Species Specific

A comprehensive survey was performed to assess fungal populations associated with crown and root rot of wheat throughout the main wheat-growing areas of Azerbaijan. Samples were taken from 76 fields; 630 fungal strains were isolated, identified, and evaluated for pathogenicity. The identification was conducted with morphological and molecular tools such as species-specific PCR and DNA sequencing of the internal transcribed spacer (ITS) and translation elongation factor 1-α (EF1-α) loci. The fungus found in the greatest number of fields (44) was Fusarium culmorum with 192 isolates, followed by F. acuminatum. Other Fusarium spp. isolates were identified: F. equiseti, F. pseudograminearum, F. graminearum, F. incarnatum, F. avenaceum, F. hostae, F. oxysporum, F. proliferatum, F. algeriense, and F. brachygibbosum. Bipolaris sorokiniana, Curvularia spicifera, Exserohilum pedicellatum, Nigrospora oryzae, and Rhizoctonia spp. isolates were also identified, associated with underground parts of wheat. Phylogenetic analyses based on ITS and EF1-α sequences of the isolates showed that the isolates belonging to the same species were clearly separated in the dendrogram. Pathogenicity assays revealed that F. culmorum, F. pseudograminearum, and F. graminearum were most aggressive; F. avenaceum, F. hostae, F. algeriense, B. sorokiniana, C. spicifera, and R. solani isolates were moderately aggressive; C. inaequalis, E. pedicellatum, and N. oryzae were weakly aggressive; and others were nonpathogenic. The result of this study exhibited the existence of a wide range of species associated with crown and root rot of wheat in Azerbaijan. Additionally, this is the first report of F. hostae, F. algeriense, C. spicifera, C. inaequalis, and N. oryzae as pathogens on wheat in Azerbaijan. Azerbaijan is the second country after Algeria in which F. algeriense was detected.

Evaluation of Australian Brassica napus genotypes for resistance to the downy mildew pathogen, Hyaloperonospora parasitica

2008 ◽  
Vol 59 (11) ◽  
pp. 1030 ◽  
Author(s):  
X. T. Ge ◽  
Hua Li ◽  
S. Han ◽  
K. Sivasithamparam ◽  
M. J. Barbetti
Keyword(s):  
Brassica Napus ◽  
Downy Mildew ◽  
Oilseed Rape ◽  
Severe Disease ◽  
Disease Symptoms ◽  
Hyaloperonospora Parasitica ◽  
Spring Type ◽  
High Level ◽  
Resistant Genotypes ◽  
Downy Mildew Disease

Downy mildew, caused by the pathogen Hyaloperonospora parasitica, is a severe disease of oilseed rape (Brassica napus) seedlings in some regions of Australia. Sixty-three cultivars of Australian spring-type oilseed rape were evaluated for their levels of resistance to five isolates of the downy mildew pathogen, using a cotyledon infection test under controlled-environment conditions. A high level of resistance, characterised by the absence of disease symptoms or only the appearance of very sparse sporulation on inoculated cotyledons, was expressed in cvv. Pioneer 45Y77 and Pioneer 46Y78. This is the first study to identify Australian genotypes of oilseed rape highly resistant to H. parasitica. The resistance to H. parasitica identified in this study will not only enable Australian oilseed rape breeders to incorporate resistance to H. parasitica into new cultivars for enhanced resistance to this disease, but will also allow direct deployment of the most highly resistant genotypes identified directly in situations and regions most conducive to the development of severe downy mildew disease.

scholarly journals Detection of Phomopsis sclerotioides in Commercial Cucurbit Field Soil by Nested Time-Release PCR

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 515-521 ◽  
Author(s):  
T. Ito ◽  
S. Fuji ◽  
E. Sato ◽  
Y. Iwadate ◽  
T. Toda ◽  
...  
Keyword(s):  
Minimum Concentration ◽  
Disease Symptoms ◽  
Specific Pcr ◽  
Phomopsis Sclerotioides ◽  
Fluorescent Pcr ◽  
Pcr Products ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Species Specific ◽  
Pcr Techniques

A polymerase chain reaction (PCR)-based molecular method to detect Phomopsis sclerotioides in soil was developed using a species-specific primer pair. To improve sensitivity of the detection, three PCR techniques were used; namely, nested PCR using the primer pair internal transcribed spacer (ITS)1 and ITS4, time-release PCR using two different DNA polymerases (recombinant Taq and AmpliTaq Gold), and fluorescent PCR to obtain fluorescent-labeled PCR products that can be analyzed by capillary electrophoresis. The latter two techniques were combined and termed nested time-release fluorescent (NTRF)-PCR. The minimum concentration of DNA required to obtain species-specific PCR products successfully was 50 fg/μg. Using the NTRF-PCR method, the fungus could be detected in sandy soil that was artificially infested at a density of 10 CFU/g. The pathogen was detected in most soil samples collected from commercial cucumber fields in which visual disease symptoms had appeared, and even in samples collected from fields where visual disease symptoms had not appeared. To prevent the invasion and establishment of root-inhabiting pathogens such as P. sclerotioides, it is critical to detect the fungus in soil as soon as possible after its introduction into a cucumber-growing region.

scholarly journals Newly Emerged Populations of Plasmopara halstedii Infecting Rudbeckia Exhibit Unique Genotypic Profiles and Are Distinct from Sunflower-Infecting Strains

2016 ◽  
Vol 106 (7) ◽  
pp. 752-761 ◽  
Author(s):  
Yazmín Rivera ◽  
Catalina Salgado-Salazar ◽  
Thomas J. Gulya ◽  
Jo Anne Crouch
Keyword(s):  
Downy Mildew ◽  
Phylogenetic Analyses ◽  
Draft Genome ◽  
The United States ◽  
Plasmopara Halstedii ◽  
Draft Genome Assembly ◽  
Host Origin ◽  
Emergent Pathogen ◽  
Pathogen Populations ◽  
Downy Mildew Disease

The oomycete Plasmopara halstedii emerged at the onset of the 21st century as a destructive new pathogen causing downy mildew disease of ornamental Rudbeckia fulgida (rudbeckia) in the United States. The pathogen is also a significant global problem of sunflower (Helianthus annuus) and is widely regarded as the cause of downy mildew affecting 35 Asteraceae genera. To determine whether rudbeckia and sunflower downy mildew are caused by the same genotypes, population genetic and phylogenetic analyses were performed. A draft genome assembly of a P. halstedii isolate from sunflower was generated and used to design 15 polymorphic simple sequence repeat (SSR) markers. SSRs and two sequenced phylogenetic markers measured differentiation between 232 P. halstedii samples collected from 1883 to 2014. Samples clustered into two main groups, corresponding to host origin. Sunflower-derived samples separated into eight admixed subclusters, and rudbeckia-derived samples further separated into three subclusters. Pre-epidemic rudbeckia samples clustered separately from modern strains. Despite the observed genetic distinction based on host origin, P. halstedii from rudbeckia could infect sunflower, and exhibited the virulence phenotype of race 734. These data indicate that the newly emergent pathogen populations infecting commercial rudbeckia are a different species from sunflower-infecting strains, notwithstanding cross-infectivity, and genetically distinct from pre-epidemic populations infecting native rudbeckia hosts.

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