Sunflower resistance to multiple downy mildew pathotypes revealed by recognition of conserved effectors of the oomycete Plasmopara halstedii.

Over the last 40 years, new sunflower downy mildew isolates (Plasmopara halstedii) have overcome major gene resistances in sunflower, requiring the identification of additional and possibly more durable broad-spectrum resistances. Here, 354 RXLR effectors defined in silico from our new genomic data were classified in a network of 40 connected components sharing conserved protein domains. Among 205 RXLR effector genes encoding conserved proteins in 17 P.

Genomic Prediction of Sunflower Hybrids Oil Content.

Prediction of hybrid performance using incomplete factorial mating designs is widely used in breeding programs including different heterotic groups. Based on the general combining ability (GCA) of the parents, predictions are accurate only if the genetic variance resulting from the specific combining ability is small and both parents have phenotyped descendants. Genomic selection (GS) can predict performance using a model trained on both phenotyped and genotyped hybrids that do not necessarily include all hybrid parents.

Molecular diversity of sunflower populations maintained as genetic resources is affected by multiplication processes and breeding for major traits.

SNP genotyping of 114 cultivated sunflower populations showed that the multiplication process and the main traits selected during breeding of sunflower cultivars drove molecular diversity of the populations. The molecular diversity in a set of 114 cultivated sunflower populations was studied by single-nucleotide polymorphism genotyping. These populations were chosen as representative of the 400 entries in the INRA collection received or developed between 1962 and 2011 and made up of land races, open-pollinated varieties, and breeding pools.

RXLR and CRN Effectors from the Sunflower Downy Mildew Pathogen Induce Hypersensitive-Like Responses in Resistant Sunflower Lines.

is an obligate biotrophic oomycete causing downy mildew disease on sunflower, , an economically important oil crop. Severe symptoms of the disease (e.g.

The sunflower downy mildew pathogen Plasmopara halstedii.

Unlabelled: Downy mildew of sunflower is caused by Plasmopara halstedii (Farlow) Berlese & de Toni. Plasmopara halstedii is an obligate biotrophic oomycete pathogen that attacks annual Helianthus species and cultivated sunflower, Helianthus annuus. Depending on the sunflower developmental stage at which infection occurs, the characteristic symptoms range from young seedling death, plant dwarfing, leaf bleaching and sporulation to the production of infertile flowers.

Combined linkage and association mapping of flowering time in Sunflower (Helianthus annuus L.).

Association mapping and linkage mapping were used to identify quantitative trait loci (QTL) and/or causative mutations involved in the control of flowering time in cultivated sunflower Helianthus annuus. A panel of 384 inbred lines was phenotyped through testcrosses with two tester inbred lines across 15 location × year combinations. A recombinant inbred line (RIL) population comprising 273 lines was phenotyped both per se and through testcrosses with one or two testers in 16 location × year combinations.

Positional cloning of a candidate gene for resistance to the sunflower downy mildew, Plasmopara halstedii race 300.

The resistance of sunflower to Plasmopara halstedii is conferred by major resistance genes denoted Pl. Previous genetic studies indicated that the majority of these genes are clustered on linkage groups 8 and 13. The Pl6 locus is one of the main clusters to have been identified, and confers resistance to several P.

Sunflower genetic, genomic and ecological resources.

Long a major focus of genetic research and breeding, sunflowers (Helianthus) are emerging as an increasingly important experimental system for ecological and evolutionary studies. Here, we review the various attributes of wild and domesticated sunflowers that make them valuable for ecological experimentation and describe the numerous publicly available resources that have enabled rapid advances in ecological and evolutionary genetics. Resources include seed collections available from germplasm centres at the USDA and INRA, genomic and EST sequences, mapping populations, genetic markers, genetic and physical maps and other forward- and reverse-genetic tools.

Genetic analysis of phytosterol content in sunflower seeds.

Interest in phytosterol contents due to their potential benefits for human health has been largely documented in several crop species. Studies were focused mainly on total sterol content and their concentration or distribution in seed. This study aimed at providing new insight into the genetic control of total and individual sterol contents in sunflower seed through QTL analyses in a RIL population characterized over 2 years showing contrasted rainfall during seed filling.

Consensus mapping of major resistance genes and independent QTL for quantitative resistance to sunflower downy mildew.

Major gene resistance to sunflower downy mildew (Plasmopara halstedii) races 304 and 314 was found to segregate independently from the resistance to races 334, 307 and 304 determined by the gene Pl2, already positioned on Linkage Group (LG) 8 of sunflower molecular maps. Using a consensus SSR-SNP map constructed from the INEDI RIL population and a new RIL population FU × PAZ2, the positions of Pl2 and Pl5 were confirmed and the new gene, denoted Pl21, was mapped on LG13, at 8 cM from Pl5. The two RIL populations were observed for their quantitative resistance to downy mildew in the field and both indicated the existence of a QTL on LG8 at 20-40 cM from the major resistance gene cluster.

Quantifying physiological determinants of genetic variation for yield potential in sunflower. SUNFLO: a model-based analysis.

Present work focussed on improving the description of organogenesis, morphogenesis and metabolism in a biophysical plant model (SUNFLO) applied to sunflower (Helianthus annuus L.). This first version of the model is designed for potential growth conditions without any abiotic or biotic stresses.

Single nucleotide polymorphisms reveal multiple introductions into France of Plasmopara halstedii, the plant pathogen causing sunflower downy mildew.

Plasmopara halstedii, the causal agent of sunflower downy mildew, displays a gene-for-gene interaction with its host plant, Helianthus annuus and other species of the genus. Monitoring of the evolution of virulent races in France over a 19-year period led to the identification of 14 different races (or pathotypes). Twelve expressed sequence tag (EST)-derived markers displaying SNPs and insertion-deletion variations have recently been identified in P.

Comparative genetic analysis of quantitative traits in sunflower (Helianthus annuus L.) 3. Characterisation of QTL involved in resistance to Sclerotinia sclerotiorum and Phoma macdonaldi.

One hundred and fifty F(2)-F(3) families from a cross between two inbred sunflower lines FU and PAZ2 were used to map quantitative trait loci (QTL) for resistance to white rot (Sclerotinia sclerotiorum) attacks of terminal buds and capitula, and black stem ( Phoma macdonaldii). A genetic linkage map of 18 linkage groups with 216 molecular markers spanning 1,937 cM was constructed. Disease resistances were measured in field experiments for S.

Comparative genetic analysis of quantitative traits in sunflower (Helianthus annuus L.). 2. Characterisation of QTL involved in developmental and agronomic traits.

Seed weight and oil content are important properties of cultivated sunflower under complex genetic and environmental control, and associated with morphological and developmental characteristics such as plant height or flowering dates. Using a genetic map with 290 markers for a cross between two inbred sunflower lines and 2 years of observations on F3 families, QTL controlling seed weight, oil content, plant height, plant lodging, flowering dates, maturity dates and delay from flowering to maturity were detected. QTL detected were compared between the F2 and F3 generations and between the 2 years of testing for the F3 families in 1997 and 1999.

Identification of non-TIR-NBS-LRR markers linked to the Pl5/ Pl8 locus for resistance to downy mildew in sunflower.

The resistance of sunflower, Helianthus annuus L., to downy mildew, caused by Plasmopara halstedii, is conferred by major genes denoted by Pl. Using degenerate and specific primers, 16 different resistance gene analogs (RGAs) have been cloned and sequenced.

Comparative genetic analysis of quantitative traits in sunflower ( Helianthus annuus L.) 1. QTL involved in resistance to Sclerotinia sclerotiorum and Diaporthe helianthi.

Sclerotinia sclerotiorum and Diaporthe helianthi are important pathogens of sunflower ( Helianthus annuus L.). Two hundred and twenty F2-F3 families were developed from an intraspecific cross between two inbred sunflower lines XRQ and PSC8.

Molecular analysis of a major locus for resistance to downy mildew in sunflower with specific PCR-based markers.

Resistance of sunflower to the obligate parasite Plasmopara halstedii is conferred by specific dominant genes, denoted Pl. The Pl6 locus confers resistance to all races of P. halstedii except one, and must contain at least 11 tightly linked genes each giving resistance to different downy mildew races.

Cloning of molecular markers for disease resistance in sunflower, Helianthus annuus L.

A candidate-gene approach to analyse the resistance of plants to phytopathogenic fungi is presented. The resistance of sunflower (Helianthus annuus L.) to downy mildew (Plasmopara halstedii) shows a gene-for-gene interaction (monogenic resistance), whereas resistance to white rot (Sclerotinia sclerotiorum) is quantitative, with different levels of resistance for different plant parts.

RFLP and RAPD mapping of the sunflower Pl1 locus for resistance to Plasmopara halstedii race 1.

The Pl1 locus in sunflower, Helianthus annuus L., conferring resistance to downy mildew, Plasmopara halstedii, race 1 has been located in linkage group 1 of the consensus RFLP map of the cultivated sunflower. Bulked segregant analyses were used on 135 plants of an F2 progeny from a cross between a downy mildew susceptible line, GH, and RHA266, a line carrying Pl1.

Assessment of inter- and intra-inbred line variability in sunflower (Helianthus annuus) by RFLPs.

The restriction fragment length polymorphism (RFLP) between 26 sunflower inbred lines was evaluated with 81 probe-enzyme combinations involving 51 cDNA clones and 4 restriction enzymes (HindIII, EcoRI, EcoRV, and BglII). An average of 4.6 fragments and 4.

Development of a consensus linkage RFLP map of cultivated sunflower (Helianthus annuus L.).

This paper provides the first description of a consensus map of the cultivated sunflower genome (Helianthus annuus L., n=17 chromosomes), based on RFLP. A total of 180 probe-enzyme combinations were mapped on at least one of five segregating progenies (three F2 and two BC1 populations), revealing 237 loci that did not show any distortion of segregation.

RFLP studies of genetic relationships among inbred lines of the cultivated sunflower, Helianthus annuus L.: evidence for distinct restorer and maintainer germplasm pools.

One-hundred-and-eighty-one nuclear DNA probes were used to examine restriction-fragment length polymorphism in inbred lines of the cultivated sunflower (Helianthus annuus L.). The probes were from six libraries: two genomic libraries - one made with PstI and the other with HindIII, and four cDNA libraries - from etiolated plantlets, green leaves, ovaries, petals and anthers.

Mitochondrial DNA RFLP and genetical studies of cytoplasmic male sterility in the sunflower (Helianthus annuus).

Fifteen sunflower (Helianthus annuus L.) cytoplasmic male-sterile, and a single male-fertile, cytotypes were studied by both mtDNA (mitochondrial DNA) restriction fragment length polymorphism (RFLP) and genetical analysis of male-fertility restoration patterns. It was found by multivariate analysis that the two methods of identification of cytoplasmic male sterility (CMS) should be of use in sunflower breeding programs.