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 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.

Lipid Peroxidation and Antioxidant Activities Involved in Resistance Response against Downy Mildew in Opium Poppy

2010 ◽  
Vol 158 (2) ◽  
pp. 88-92 ◽  
Author(s):  
Mukesh K. Dubey ◽  
Ajit K. Shasany ◽  
Om P. Dhawan ◽  
Ashutosh K. Shukla ◽  
Suman P. S. Khanuja
Keyword(s):  
Lipid Peroxidation ◽  
Downy Mildew ◽  
Antioxidant Activities ◽  
Opium Poppy ◽  
Resistance Response

Peronosporales of Skadovsky Zvenigorod Biological Station (Moscow Region)

2018 ◽  
Vol 52 (1) ◽  
pp. 91-100
Author(s):  
E. Yu. Blagoveshchenskaya
Keyword(s):  
Downy Mildew ◽  
European Part ◽  
Moscow Region ◽  
State University ◽  
Biological Station ◽  
Annotated List ◽  
European Part Of Russia ◽  
First Time ◽  
Moscow State University

The paper provides the results of seven-year study of downy mildew on Skadovsky Zvenigorod Biological Station of Moscow State University (ZBS MSU, Moscow Region). A total of 29 species of Peronosporales (Oomycota) were revealed during the study. An annotated list of species is presented, among them Peronospora anemones is recorded for the first time for Russia, P. chelidonii and P. stachydis are new for the European part of Russia, 8 species are new for the Moscow Region.

scholarly journals Comparison of Three Fungicide Spray Advisories for Lettuce Downy Mildew

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 895-900 ◽  
Author(s):  
B. M. Wu ◽  
K. V. Subbarao ◽  
A. H. C. van Bruggen ◽  
S. T. Koike
Keyword(s):  
Downy Mildew ◽  
Drip Irrigation ◽  
Leaf Wetness ◽  
Lettuce Downy Mildew ◽  
Advisory System ◽  
System 2 ◽  
Forecasting System ◽  
Low Incidence ◽  
System 1 ◽  
First Time

Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform satisfactorily. In this study, the advisory system was modified by incorporating a pathogen survival component (system 1) or both survival and sporulation components (system 2). These systems were then evaluated in commercial lettuce fields in coastal California during 1996-1998. Three or four treatments were carried out in each field: (i) no spray; (ii) sprays as scheduled by the growers; (iii) sprays following modified system 1; and (iv) sprays following the original advisory system (1996) or modified system 2 (1998). Downy mildew incidence was evaluated every 2 to 9 days. In fields with drip irrigation, the number of fungicide applications was reduced by one or two regardless of the advisory system used compared to the grower's calendar-based schedule, although one unnecessary spray was recommended in 1996 at Soledad and 1997 at Salinas. Under all three systems, disease levels were low (incidence <25% and about 1 lesion per plant) for fields with drip irrigation, but not for fields with sprinklers (incidence up to 100% and 5 to 10 lesions per plant). For the first time, we established that survival and sporulation components are not needed for a lettuce downy mildew forecasting system. Instead, a threshold with a shorter period of morning leaf wetness and high temperatures were found to have potential for improving forecasting efficiency.

scholarly journals Resistance Response of Maize Germplasm to Downy Mildew [Peronosclerospora philipinensis]

2018 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Syahrir Pakki ◽  
Mappaganggang Mappaganggang
Keyword(s):  
Downy Mildew ◽  
Block Design ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Average Intensity ◽  
Standard Score ◽  
Resistance Response ◽  
Maize Germplasm ◽  
Randomized Block Design ◽  
Moderately Resistant

<p>Two experiments to study responses of resistance of maize germplasm to downy mildew (Peronosclerospora philipinensis) have been conducted. Both experiments were arranged in randomized block design with two replication. The treatments in each experiment (2014 and 2016) were 70 maize accessions. The accessions were planted in planting distant of 75 cm × 20 cm, in 5 m rows, resulting in 20 plants per row. In every 10 rows, two check varieties were planted, i.e. one susceptible and one resistant variety. Ten days prior to planting, the soil was fertilized with mixed fertilizers consisted of urea, ZA, SP36, and KCl at a dose of 100, 100, 100, and 100 kg/ha, respectively. Fertilization II and III was given at 30 days after planting, and 45 days after planting with a dose of 100 kg urea/ha. As a source of inoculum downy mildew, around the repeated plot was planted with varieties Anoman variety (susceptible variety) that was inoculated with a suspension of downy mildew pathogen. Observation was conducted at 25, 35, and 55 days after planting, with the standard score of resistant to downy mildew, followed: 0–10% = resistant, 11–25% = moderately resistant, 26–50% = moderately susceptible, &gt;50% = susceptible. The result of the experiments showed that there were 5 accessions resistant to downy mildew (P. philipinensis), i.e. CML 440×MR4-9-30-3, 664, 60, 572, and 554 with the intensity of downy mildew infection ranged from 5 to 10%. Twelve other accessions were classified as moderately resistant, i.e. CML 440×MR4-9-98-2, 440×MR4-9-98-4 CML, CML 440×MR4-9-124-1, 66, 71, 319, 108, 73, 48, 105, 554, and 682 with intensity of infection ranged from 13 to 25%. At the same experiments, the average intensity of downy mildew infection on susceptible check varieties reached 100 percent.</p>

Orally administered antigen can reduce or exacerbate pathology in an animal model of inflammatory arthritis dependent upon the timing of administration

2022 ◽  
Author(s):  
Gavin Robertson Meehan ◽  
Iain B McInnes ◽  
James M Brewer ◽  
Paul Garside
Keyword(s):  
Inflammatory Arthritis ◽  
Opposite Effect ◽  
Short Communication ◽  
Serum Antibody ◽  
Joint Inflammation ◽  
Disease Symptoms ◽  
Considerable Research ◽  
Self Tolerance ◽  
The Impact ◽  
Specific Tolerance

Currently, treatments for rheumatoid arthritis (RA) are focussed on treatment of disease symptoms rather than addressing the cause of disease, which could lead to remission and cure. Central to disease development is the induction of autoimmunity through a breach of self-tolerance. There is considerable research in RA focussed on antigens and approaches to re-establish antigen specific tolerance. A crucial step in this research is to employ appropriate animal models to test prospective antigen specific immunotherapies, preferably in the context of joint inflammation. In this short communication, we use our previously developed model of antigen specific inflammatory arthritis in which OVA-specific TcR tg T cells drive breach of tolerance to endogenous antigens to determine the impact that the timing of therapy administration has upon disease progression. Using antigen feeding to induce tolerance we demonstrate that administration prior to articular challenge results in a reduced disease score as evidenced by pathology and serum antibody responses. By contrast, feeding antigen after articular challenge had the opposite effect and resulted in the exacerbation of pathology. Although preliminary, these data suggest that the timing of antigen administration may be key to the success of tolerogenic immunotherapies. This has important implications for the timing of potential tolerogenic therapies in patients.

scholarly journals Omnivorous Behaviour of the Agouti (Dasyprocta leporina): A Neotropical Rodent with the Potential for Domestication

Scientifica ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Kegan Romelle Jones ◽  
Kavita Ranjeeta Lall ◽  
Gary Wayne Garcia
Keyword(s):  
Rural Communities ◽  
Trinidad And Tobago ◽  
Short Communication ◽  
Nutrient Requirements ◽  
The West ◽  
Field Station ◽  
Zenaida Macroura ◽  
Neotropical Rodent ◽  
The University ◽  
First Time

The agouti is a Neotropical rodent which is mainly utilized for its meat in rural communities. Recently, captive rearing of these animals by wildlife farmers have increased in the Neotropics. This short communication consists of observation of feeding behaviour of captive reared agoutis at the University of the West Indies Field Station in Trinidad and Tobago. This is the first time in Trinidad and Tobago that meat consumption and the omnivorous behaviour of the agouti have been documented in the literature. The consumption of chicken (Gallus domesticus) eggs, dead chickens, and a brown dove (Zenaida macroura) by captive reared agoutis was noted. This document described the omnivorous behaviour of the agouti which is primarily considered a frugivorous animal. Similar studies in South America have shown that wild and captive reared agoutis consumed animal matter. Further work must be done on the dietary needs and nutrient requirements of the agouti at different physiological states.

scholarly journals Transcriptional regulation of stilbene synthases in grapevine germplasm differentially susceptible to downy mildew

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mario Ciaffi ◽  
Anna Rita Paolacci ◽  
Marco Paolocci ◽  
Enrica Alicandri ◽  
Valentina Bigini ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Downy Mildew ◽  
Transcriptional Activation ◽  
Constitutive Expression ◽  
Stilbene Synthase ◽  
Disease Symptoms ◽  
Adaptive Resistance ◽  
Genes Encoding ◽  
The Impact ◽  
Stilbene Biosynthesis

Abstract Background To limit the impact of the downy mildew disease of grapevine and reduce the need to recur to chemical treatments, an effective strategy might be recovering adaptive resistance traits in both cultivated and wild V. vinifera germplasm. Considering that stilbenes represent the most important class of phytoalexins in the Vitaceae, the constitutive expression and transcriptional activation of all the functional members of the stilbene synthase gene family were analysed in a group of nine grapevine genotypes following artificial infection with the oomycete Plasmopara viticola, the causal agent of the disease. In addition, in the same genotypes we analyzed the expression of genes encoding for two transcription factors involved in the transcriptional regulation of the stilbene synthase genes, namely VvMYB14 and VvMYB15, and of genes encoding for chalcone synthases. Results Downy mildew incidence and severity ranged from nihil to high in the grapevine genotypes considered, being low to moderate in a subgroup of V. vinifera genotypes. The constitutive expression of the stilbene synthase genes as well as the extent of their transcriptional activation following P. viticola inoculation appeared to be inversely related to the proneness to develop disease symptoms upon infection. In a specular manner, following P. viticola inoculation all the chalcone synthase genes were up-regulated in the susceptible grapevine genotypes and down-regulated in the resistant ones. The infection brought by P. viticola appeared to elicit a co-ordinated and sequential transcriptional activation of distinct stilbene synthase genes subsets, each of which may be regulated by a distinct and specific MYB transcription factor. Conclusions The present results suggest that the induction of stilbene biosynthesis may contribute to the basal immunity against the downy mildew of grapevine, thus representing an adaptive resistance trait to recover, in both cultivated and wild V. vinifera germplasm. During the early stages of P. viticola infection, an antagonistic interaction between flavonol and stilbene biosynthesis might occur, whose outcome might determine the subsequent extent of disease symptoms. Further studies are needed to decipher the possible regulatory mechanisms involved in the antagonistic crosstalk between these two metabolic pathways in resistant and susceptible genotypes in response to P. viticola.

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.

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