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

2013 ◽  
Vol 57 ◽  
pp. 42-47 ◽  
Author(s):  
Wolfgang Grasse ◽  
Reinhard Zipper ◽  
Maria Totska ◽  
Otmar Spring
Keyword(s):  
Downy Mildew ◽  
Plasmopara Halstedii

Symptoms Development as Tools to Differentiate Dorizontal Resistance in Sunflower

Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Cipta Meliala ◽  
Felicity Fear ◽  
Denis Tourvieille de Labrouhe
Keyword(s):  
Downy Mildew ◽  
Natural Infection ◽  
Resistance Mechanism ◽  
Good Method ◽  
Vegetative Stage ◽  
Horizontal Resistance ◽  
Symptom Development ◽  
Plasmopara Halstedii ◽  
Controlled Conditions ◽  
Symptom Progression

Downy mildew symptoms caused by Plasmopara halstedii encountered in sunflower plantation are varied. This variation may be related to the resistance mechanism presented by plant to the invasion of the fungus. Our objectives were firstly is to evaluate symptom development after fungus race 710 inoculation on some vegetative stage of susceptible hybrid. Second objective is to evaluate the reaction some sunflower genotypes after fungus inoculation. The study was conducted under controlled conditions or under netting cages in the field. The development of downy mildew symptoms were affected by all factors studied. Shoot inoculation may present a good method to produce downy mildew symptom similar to the natural infection. Downy mildew symptom progression may be used to screen a genotype with a horizontal resistance.

scholarly journals Updated Characterization of Races of Plasmopara halstedii and Entomopathogenic Fungi as Endophytes of Sunflower Plants in Axenic Culture

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Pedro Miranda-Fuentes ◽  
Ana B. García-Carneros ◽  
Leire Molinero-Ruiz
Keyword(s):  
Plant Growth ◽  
Downy Mildew ◽  
Entomopathogenic Fungi ◽  
Genetic Resistance ◽  
Axenic Culture ◽  
Plasmopara Halstedii ◽  
Successful Establishment ◽  
Axenic Conditions ◽  
Highly Virulent

The management of downy mildew (Plasmopara halstedii) in sunflower, is heavily dependent on genetic resistance, whilst entomopathogenic fungi (EF) can reduce other sunflower diseases. In this work, we characterized P. halstedii from Spain and other countries collected in the past few years. Twenty-three races were identified (the most frequent in Spain being 310, 304, 705 and 715), with an increasing proportion of highly virulent races. Five isolates from countries other than Spain overcame the resistance in RHA-340. In addition, we assessed the efficacy of five EF against downy mildew and their effects on sunflower growth in axenic conditions. None of the entomopathogens reduced disease severity, nor did they have any effect on plant growth when applied together with P. halstedii. In contrast, three EF reduced some of the plant growth variables in the absence of the pathogen. Microbiological and molecular diagnostics suggest that the axenic system and the short experimental time used in this study did not favor the successful establishment of EF in the plants or their potential biocontrol effect. Our results show a shift in P. halstedii racial patterns and suggest that soil as a growth substrate and long infection times are needed for EF effectiveness against downy mildew.

scholarly journals DISTRIBUTION AND RACE COMPOSITION OF DOWNY MILDEW (Plasmopara halstedii (Farl.) Berl. and de Toni) IN BULGARIA / EXTENSION Y RAZAS DEL MILDIU (Plasmopara halstedii (Farl.) Berl. y de Toni) EN BULGARIA / ÉTENDUE ET RACES DE LA ROUILLE (Plasmopara halstedii (Farl.) Berl. and de Toni) EN BULGARIE

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 25-32
Author(s):  
P.S. Shindrova
Keyword(s):  
Downy Mildew ◽  
Resistance Gene ◽  
The Other ◽  
Plasmopara Halstedii ◽  
North West ◽  
North East ◽  
Race 1 ◽  
Race 2 ◽  
Production Areas ◽  
Number Of Authors

SUMMARY Downy mildew caused by the fungus Plasmopara halstedii is the main disease on sunflower in Bulgaria. In recent years a number of authors have reported the occurrence of new more virulent races of the pathogen. According to other authors these races demonstrate resistance to the fungicides used up to now. This fact is rather alarming and imposes the necessity of annual researches with the aim of following the changes in the downy mildew race variability. In the period 1995-1997 downy mildew isolates were collected from the following locations: Bourgas, Boyanovo, Karnobat, Ognyanovo, Selanovtsi, Kroushari, Lovech, Koubrat, Brashlyan, Sitovo, Tervel, Targovishte, IWS “Dobroudja” and Dobrich. The samples were assessed for virulence on a set of sunflower differential - lines under greenhouse conditions. The obtained results do not reveal a great race variability of downy mildew population in Bulgaria. In the period of study two races of the pathogen were identified: race 1 which infects the differential lines without genes for resistance to the pathogen. It is distributed in all sunflower production areas of the country. The other one is race 2. It is of limited distribution and has been registered in individual fields of north-east and north-west Bulgaria. It attacks the differential lines carrying the resistance gene Pl-1.

SUNFLOWER: DESCRIPTION OF SUNFLOWER LINES IN THE CONTEXT OF THEIR RESISTANCE TO DOWNY MILDEW (PLASMOPARA HALSTEDII (FARL.) BERL. ЕT DE TONI)

2021 ◽  
Author(s):  
V.A. GAVRILOVA ◽  
◽  
T.G. STUPNIKOVA ◽  
L.G. MAKAROVA ◽  
◽  
...  
Keyword(s):  
Field Study ◽  
Downy Mildew ◽  
General Description ◽  
Plasmopara Halstedii

This catalogue presents the results of the three-year (2016–2018) field study of 325 sunflower lines and cultivars from the VIR collection in the context of their resistance to downy mildew (caused by Plasmopara halstedii (Farl.) Berl. еt de Toni). In addition to general description, lines unaffected by downy mildew during all three years of testing are identified, along with those that were resistant in 2016 and 2018 but showed susceptibility in 2017. The catalogue is addressed to plant pathologists, geneticists and breeders.

Colocation of downy mildew (Plasmopara halstedii) resistance genes in sunflower (Helianthus annuus L.)

Euphytica ◽  
1996 ◽  
Vol 91 (2) ◽  
pp. 225-228 ◽  
Author(s):  
Patricia Roeckel-Drevet ◽  
Geneviève Gagne ◽  
Said Mouzeyar ◽  
Laurent Gentzbittel ◽  
Jacqueline Philippon ◽  
...  
Keyword(s):  
Helianthus Annuus ◽  
Downy Mildew ◽  
Resistance Genes ◽  
Plasmopara Halstedii ◽  
Helianthus Annuus L

Development of a polymerase chain reaction diagnostic test for the detection of the biotrophic pathogen Plasmopara halstedii in sunflower

1999 ◽  
Vol 45 (9) ◽  
pp. 797-803 ◽  
Author(s):  
Patricia Roeckel-Drevet ◽  
Jeanne Tourvieille ◽  
Joël R Drevet ◽  
Véronique Says-Lesage ◽  
Paul Nicolas ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Helianthus Annuus ◽  
Downy Mildew ◽  
Random Amplified Polymorphic Dna ◽  
Parasitic Fungus ◽  
Sequence Information ◽  
Chain Reaction ◽  
Plasmopara Halstedii ◽  
Polymerase Chain

The obligate parasitic fungus-like organism Plasmopara halstedii (Farl.) Berl. et De Toni, is the causal agent of downy mildew disease in sunflower (Helianthus annuus). New races of this economically important parasite are regularly detected throughout the world. In addition, fungicide-resistant isolates have been reported in Europe and North America. These observations of parasite evolution, as well as the risk of propagation of the disease by infected seeds, means that it is necessary to guarantee the absence of Plasmopara halstedii in seed shipments. We report here the development of a rapid assay that can be used to detect infection by Plasmopara halstedii in plant tissues. Based on the nucleotide sequence information obtained from one cloned random amplified polymorphic DNA fragment, specific oligonucleotides were designed and used as primers for in vitro DNA amplification by polymerase chain reaction. An amplification product was detected on agarose gel stained with ethidium bromide when DNA from various Plasmopara halstedii races was tested, whereas no amplified DNA was detected when DNA from other origins was tested, including DNA from the host plant. The sensitivity of the technique was evaluated. The assay successfully reveals the presence of Plasmopara halstedii in infected sunflower plants prior to sporulation.Key words : diagnosis, polymerase chain reaction, SCAR, downy mildew, Helianthus annuus.

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