The improvement of genetic resistance to Plasmopara halstedii pathogen and Orobanche cumana parasite, in sunflower genotypes, resistant to herbicides

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.

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History of the race structure of Orobanche cumana and the breeding of sunflower for resistance to this parasitic weed: A review

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2015134-8080 ◽

2015 ◽

Vol 13 (4) ◽

pp. e10R01 ◽

Cited By ~ 27

Author(s):

Leire Molinero-Ruiz ◽

Philippe Delavault ◽

Begoña Pérez-Vich ◽

Maria Pacureanu-Joita ◽

Mariano Bulos ◽

...

Keyword(s):

Eastern Europe ◽

Integrated Management ◽

Genetic Resistance ◽

Farming Systems ◽

Parasitic Weed ◽

Orobanche Cumana ◽

History Of ◽

Changing Patterns ◽

Harmful Effects

Broomrape, caused by Orobanche cumana, has affected sunflowers since the early 20th century in Eastern Europe. Currently, it limits sunflower oil production in Southern and Eastern Europe and in some areas of Asia, causing around 50% seed losses when susceptible hybrids are grown. Covered in this review are aspects such as: biological processes that are common to Orobanche spp. and/or particular to O. cumana in sunflower, genetic resistance and its mechanisms, races of the parasite identified in different countries throughout the time and their increasing virulence, and breeding for resistance to some herbicides as a novel control option. The main purpose is to present an updated and, as far as possible, complete picture of the way both the parasitic weed and its host crop have evolved in time, and how they co-exist in the current agriculture. Additionally, we propose a system for determining the races of the parasite that can be internationally adopted from now. In the context of minimal harmful effects on the environment, changing patterns of land use in farming systems, and global environment changes, the final goal of this work is to provide all those interested in parasites from field crops and their integrated management compiled information on the sunflower – O. cumana system as a case study.

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Genetic and physiological characterization of sunflower resistance provided by the wild-derived OrDeb2 gene against highly virulent races of Orobanche cumana Wallr

Theoretical and Applied Genetics ◽

10.1007/s00122-021-03979-9 ◽

2021 ◽

Author(s):

Mónica Fernández-Aparicio ◽

Lidia del Moral ◽

Stéphane Muños ◽

Leonardo Velasco ◽

Begoña Pérez-Vich

Keyword(s):

Genetic Resistance ◽

Resistance Mechanism ◽

Kinase Domain ◽

Genomic Region ◽

Snp Markers ◽

Resistance Response ◽

Physiological Characterization ◽

Orobanche Cumana ◽

Genes Encoding ◽

Highly Virulent

Abstract Key message OrDeb2 confers post-attachment resistance to Orobanche cumana and is located in a 1.38 Mbp genomic interval containing a cluster of receptor-like kinase and receptor-like protein genes with nine high-confidence candidates. Abstract Sunflower broomrape is a holoparasitic angiosperm that parasitizes on sunflower roots, severely constraining crop yield. Breeding for resistance is the most effective method of control. OrDeb2 is a dominant resistance gene introgressed into cultivated sunflower from a wild-related species that confers resistance to highly virulent broomrape races. The objectives of this study were as follows: (i) locate OrDeb2 into the sunflower genome and determine putative candidate genes and (ii) characterize its underlying resistance mechanism. A segregating population from a cross between the sunflower resistant line DEB2, carrying OrDeb2, and a susceptible line was phenotyped for broomrape resistance in four experiments, including different environments and two broomrape races (FGV and GTK). This population was also densely genotyped with microsatellite and SNP markers, which allowed locating OrDeb2 within a 0.9 cM interval in the upper half of Chromosome 4. This interval corresponded to a 1.38 Mbp genomic region of the sunflower reference genome that contained a cluster of genes encoding LRR (leucine-rich repeat) receptor-like proteins lacking a cytoplasmic kinase domain and receptor-like kinases with one or two kinase domains and lacking an extracellular LRR region, which were valuable candidates for OrDeb2. Rhizotron and histological studies showed that OrDeb2 determines a post-attachment resistance response that blocks O. cumana development mainly at the cortex before the establishment of host-parasite vascular connections. This study will contribute to understand the interaction between crops and parasitic weeds, to establish durable breeding strategies based on genetic resistance and provide useful tools for marker-assisted selection and OrDeb2 map-based cloning.

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Determination of Virulence Phenotypes of Plasmopara halstedii in the United States

Plant Disease ◽

10.1094/pdis-10-19-2063-re ◽

2020 ◽

Vol 104 (11) ◽

pp. 2823-2831 ◽

Cited By ~ 1

Author(s):

Michelle A. Gilley ◽

Thomas J. Gulya ◽

Gerald J. Seiler ◽

William Underwood ◽

Brent S. Hulke ◽

...

Keyword(s):

Disease Management ◽

Great Plains ◽

Resistance Genes ◽

Genetic Resistance ◽

The United States ◽

Management Tool ◽

Plasmopara Halstedii ◽

Pathogen Virulence ◽

Standard Set ◽

The U.S

Downy mildew, caused by Plasmopara halstedii (Farl.) Berl. and de Toni, is an economically important disease in cultivated sunflowers, Helianthus annuus L. Resistance genes incorporated into commercial hybrids are used as an effective disease management tool, but the duration of effectiveness is limited as virulence evolves in the pathogen population. A comprehensive assessment of pathogen virulence was conducted in 2014 and 2015 in the U.S. Great Plains states of North Dakota and South Dakota, where approximately 75% of the U.S. sunflower is produced annually. The virulence phenotypes (and races) of 185 isolates were determined using the U.S. standard set of nine differentials. Additionally, the virulence phenotypes of 61 to 185 isolates were determined on 13 additional lines that have been used to evaluate pathogen virulence in North America and/or internationally. Although widespread virulence was identified on several genes, new virulence was identified on the Pl8 resistance gene, and no virulence was observed on the PlArg, Pl15, Pl17 and Pl18 genes. Results of this study suggest that three additional lines should be used as differentials and agree with previous studies that six lines proposed as differentials should be used in two internationally accepted differential sets. For effective disease management using genetic resistance, it is critical that virulence data be relevant and timely. This is best accomplished when pathogen virulence is determined frequently and by using genetic lines containing resistance genes actively incorporated into commercial cultivars.

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Using sowing date modification and genetic resistance to manage sunflower broomrape (Orobanche cumana Wallr.)

Helia ◽

10.2298/hel1359017a ◽

2013 ◽

Vol 36 (59) ◽

pp. 17-34 ◽

Cited By ~ 1

Author(s):

B. Akhtouch ◽

L. Molinero-Ruiz ◽

J. Dominguez ◽

J.M. Melero-Vara ◽

J.M. Fernández-Martínez

Keyword(s):

Genetic Resistance ◽

Sowing Date ◽

Orobanche Cumana ◽

Sunflower Broomrape

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Symptoms Development as Tools to Differentiate Dorizontal Resistance in Sunflower

Agrotek ◽

10.30862/agt.v2i6.529 ◽

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.

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