Validation of microsatellite markers to identify Pl6, Pl8 and Plarg genes that control resistance to Plasmopara halstedii in sunflower (original) (raw)
Related papers
PCR-Based Markers Facilitating Marker Assisted Selection in Sunflower for Resistance to Downy Mildew
Crop Science, 2000
Korell et al., 1996a; Miller, 1992). These dominant resistance genes have been designated as Pl genes. Some Sunflower (Helianthus annuus L.) production is endangered by of them provide resistance to a single race of downy several diseases, necessitating sophisticated disease management strategies. Downy mildew of sunflower, incited by Plasmopara hal-mildew, whereas others impart resistance against two stedii (Farl.) Berl. et de Toni, is a major sunflower disease. Recent or more races (Miller, 1992). At the moment, most comreports of pathotypes resistant to metalaxyl [N-(2,6-dimethylphenyl)mercial hybrids are resistant to race 2 of downy mildew N-(methoxyacetyl)-DL-alanine methyl ester], which was used as a (Gulya, 1998), which was the predominant race in the seed treatment against downy mildew, showed the necessity to breed USA until 1981 (Gulya et al., 1991b). Six hybrids were for durable downy mildew resistance in future hybrids. This process resistant to the most virulent pathotype (race 5). Most can be accelerated by marker assisted selection (MAS) including breeders acknowledged that the resistance was obtained pyramiding of several resistance genes. The objective of this study from public USDA lines HA335 through HA339 that was to develop molecular markers for the Pl 2 gene of cultivated are resistant to all races (Gulya, 1998). It may be very sunflower, which confers resistance to downy mildew races 1, 2, 7, attractive for practical breeding to use, for example, the and 9. Two sets of near isogenic lines (AS110/AS110Pl 2 and S1358/ S1358Pl 2) and bulks of a segregating F 2 population were used to Pl 6 gene, which provides resistance to all known races. identify random amplified polymorphic DNA (RAPD) and amplified However, it is not advisable to use only one resistance fragment length polymorphism (AFLP) markers. Public maintainer gene. Rather, several different resistance genes should and restorer lines were used to evaluate the markers. Disease resisbe employed, either by growing different hybrids cartance was evaluated by the whole seedling immersion method. DNA rying the different resistance genes or by pyramiding was extracted from leaves at flowering. RAPD markers OPAA14 750 such genes. This strategy may extend the life cycle of and OPAC20 831 , as well as the AFLP marker E35M48-3, showed a each gene by keeping the selection pressure on the tight linkage of about 2 centimorgans (cM) to the Pl 2 locus. RAPD pathogen population as low as possible. Strong resismarker OPAA11 1008 linked to a distance of about 6 cM with the tance genes effective against all known races could be resistance locus and could be converted to a SCAR marker. Closely overcome soon by new pathogen races if used alone. linked RAPDs and the sequence characterized amplified region (SCAR) marker demonstrated their practicability for marker assisted On the other hand, hybrids that combine strong genes breeding by differentiating between resistant and susceptible germ-with already defeated hypostatic genes may be resistant plasm of a set of diverse sunflower inbred lines.
Validated Molecular Marker for Downy Mildew Disease Resistance Breeding of Sunflower: A Short Review
Journal of Agrobiotechnology, 2023
The oomycete pathogen Plasmopara halstedii responsible for sunflower downy mildew (DM), that is a significant and important disease that greatly affects the economy. As of now, there is no non-race-specific resistance for this disease and breeders are depended on race-specific resistance to control DM disease. On the other hand, using conventional breeding procedure introgression of the DM resistance genes is a long-term task due to the highly virulent and aggressive nature of the P. halstedii pathogen. Molecular markers that can be applied at the seedling stage, offers rapid response for selection with higher precision as well as a lower cost. There are currently 36 downy mildew resistance genes (R genes), designated as Pl (Pl1-Pl36, Plhra, and PlArg, in sunflowers, each with a unique linkage group (LGs). The availability of DM resistance genomic data of sunflower, related to Single Nucleotide Polymorphisms (SNP) based markers with mine allelic diversity maximize the opportunity of utilizing Marker assisted selection (MAS) techniques for downy mildew resistance breeding. This review highlights the available genetic marker and their utilization at MAS techniques for enhancing downy mildew disease resistant breeding program of sunflowers.
Molecular Markers as a Tool in Breeding for Resistance Against Sunflower Downy Mildew
2005
Sunflower production is endangered by several diseases, necessitating a sophisticated disease management. Downy mildew of sunflower incited by Plasmopara halstedii belongs to the major sunflower diseases. Recent reports of pathotypes resistant to metalaxyl showed the necessity to breed for durable resistance of future hybrids. In order to develop molecular markers for different resistance genes, bulks and near isogenic lines were analysed employing RAPD and AFLP techniques. Segregation analysis of disease resistance was performed using the whole seedling immersion method. Markers useful in indirect selection for resistance genes Pl 2 (e.g. RHA325), Pl 6 (HA335), and Pl arg (ARG1575-2) were identified. Crosses between several resistant genotypes were used in segregation and marker analyses to study the genetics of the genes involved. These experiments confirm the allelic relationship of loci Pl 2 Pl 6 and Pl 7 , whereas Pl 6 and Pl arg as well as Pl 6 and Pl 5 seem to be inherited independently. Pyramiding of the different resistance genes may result in an extended useful lifetime of the individual genes. Therefore, the markers are now employed in marker assisted selection experiments to combine for instance genes Pl 6 and Pl arg , both giving resistance to all known races so far. But also the combination of already defeated genes (like Pl 1 or Pl 2) with one of those genes giving multiple resistances may provide more durable resistance than this complex loci alone. Hence, the management of resistance against downy mildew in sunflower should employ different combinations of Pl genes, even if some of them seem to be not very effective at the moment.
Plant Breeding, 2007
The inheritance of the reaction of sunflower to downy mildew was investigated using resistant and susceptible near isogenic lines (NILs) and their F 3 families. Resistance to race 730 was evaluated using the whole seedling inoculation technique. Seventy-three F 3 families were inoculated, among which 54 families were resistant and 19 susceptible, fitting a 3 : 1 segregation ratio. F 3 families were also studied using several PCR markers. Ten markers at the Pl6 locus, specific for the resistant line, also segregated in F 3 families with a 3 : 1 ratio. The same segregation ratio occurred for microsatellite haplotypes that resembled the resistant parent, and were amplified with ORS 166 and ORS 1043. The only common fragment that was observed between resistant and susceptible parental lines was one of the TIR-NBS-LRR resistance gene analogue markers, having a restriction site. Two co-dominant cleaved amplified polymorphic sequence (CAPS) markers were obtained. The mapping data indicate that several dominant markers and two CAPS markers, developed here, completely co-segregate with the Pl6 gene conferring resistance to race 730. CAPS markers will facilitate efficient marker-assisted selection for sunflower resistance to downy mildew race 730.
SSR Markers Suitable for Marker Assisted Selection in Sunflower for Downy Mildew Resistance
Open Life Sciences, 2018
The effectiveness of Pl genes is known to be resistant to downy mildew (DM) disease affected by fungus Plasmopara halstedii in sunflower. In this study phenotypic analysis was performed using inoculation tests and genotypic analysis were carried out with three DM resistance genes Plarg, Pl13 and Pl8. A total of 69 simple sequence repeat markers and 241 F2 individuals derived from a cross of RHA-419 (R) x P6LC (S), RHA-419 (R) x CL (S), RHA-419 (R) x OL (S), RHA419 (R) x 9758R (S), HA-R5 (R) x P6LC (S) and HA89 (R) x P6LC (S) parental lines were used to identify resistant hybrids in sunflower. Results of SSR analysis using markers linked with downy mildew resistance genes (Plarg, Pl8 and Pl13) and downy mildew inoculation tests were evaluated together and ORS716 (for Plarg and Pl13), HA4011 (for Pl8) markers showed positive correlation with their phenotypic results. These results suggest that these markers are associated with DM resistance and they can be used successfully in marker-...
THE USE OF MOLECULAR MARKERS IN RESISTANCE BREEDING STUDIES SUNFLOWER
Molecular markers use commonly in recent years in plant breeding in addition to use of different breeding methods as well as to implement or accelerate of sunflower breeding programs for integrating biotechnology with traditional breeding specially to identify and to transfer resistant genes in resistance breeding. It calls marker-assisted selection (MAS) using genetic markers linked to the resistance and they are preferring highly because of providing the fast and accurate selection to accelerate of conventional breeding efforts. However, they should present high level of polymorphism, co-dominance in expression to distinguish heterozygotes from homozygotes, clear distinct allelic features to identify easily the different alleles, single copy and no pleiotropic effect, low cost or cost-efficient marker development and genotyping, easy assay/detection and automation, higher availability, etc. to use efficiently in sunflower breeding programs. Many molecular markers on determining resistant genes in some important diseases were determined in both cultural type sunflower and also wild sunflower sources then they were implemented and introgressed successfully in molecular studies and breeding programs. Different RAPD, SSR (microsatellite) RFLP, AFLP, CAPS, IFLP, NBS-LRR, TIR-NBS-LRR, STS, SCAR, TRAP, EST, etc. markers to have been determined until today to identify resistant genes in different sunflower diseases in many studies. For instance, Pl6 resistance gene to downy mildew from wild H. annuus at 42.9 cM in the inbred line HA335, Pl8 from H. argophyllus at 37.3 cM were determined in the inbred line RHA340. Similarly, The PlArg, Pl13 and Pl14 resistant genes were determined in localized on linkage group LG1 in different studies. The mapping resistance genes of downy mildew which is one of having the largest races among plant diseases was initiated MAS programs and also ameliorated the original resistance sources due to eliminated by recombination and selection by molecular markers in sunflower. In rust which damage more and effective in confectionery sunflower mainly, molecular markers linked and associated with rust resistance genes were first described for R1 race localized on LG8 found in RHA279 inbred line, Radv from RHA340, R4 from HAR3, R2 from MC29 located using SSR markers in LG9 described currently in sunflower genetic maps. In other study, 3 major QTLs in LG 4, 10 and 17 and the QTL were introgressed by backcrossing from Alternaria resistant sources utilizing MAS in sunflower. As results, MAS is so valuable breeding tool, but new molecular tools and technologies such as next-generation sequencing, high-throughput genotyping and genome wide selection will make MAS more based on the whole genome, rather than small parts with offering several advantages over genetic engineering to overcome barriers.
Biotechnology & Biotechnological Equipment, 2009
Sunflower is the most important oil crop in Bulgaria. Downy mildew, caused by the fungal pathogen Plasmopara halstedii, is one of the major diseases in sunflower that can lead to significant loss of yield, to more than 50%. Breeding for resistance is considered as the most effective method for achievement of low cost and environmentally friendly production. The present minireview is focused on the current status of knowledge related to the identification and the localization of the genes that control resistance to downy mildew in sunflower, as well as, the markers associated with the loci for this resistance in the frame of genetic linkage maps. A study, aimed at identification and mapping of chromosomal regions/markers introgressed from H. bolanderi, which confer resistance to P. halstedii in two inbred lines, was described. This research program, initiated in AgroBioInstitute in the frame of project DO02-105 "Centre for Sustainable Development of Plant and Animal Genomics" was launched for the development of sunflower breeding lines with improved resistance to fungal pathogens through MAS.
TAG Theoretical and Applied Genetics, 2001
A sunflower line, XRQ, carrying the gene Pl5, which gives resistance to all French downy mildew races shows cotyledon-limited sporulation in seedling immersion tests; consequently, segregations in crosses with other downy mildew resistance sources were tested both by this method and by a secondary infection on leaves. Pl5 was found to segregate independently of Pl7 (HA338) but to be closely linked, or allelic, with Pl8 (RHA340). F 3 and F 4 progenies from a cross with a line containing Pl2 showed that Pl5 carries resistance to race 100 which segregates independently of Pl2. The Pl5 gene was mapped on linkage group 6 of the Cartisol RFLP map, linked to two RFLP markers, ten AFLP markers and the restorer gene Rf1. Tests with downy mildew race 330 distinguished Pl5 and Pl8, the first being susceptible, the second resistant, whereas both these genes were active against race 304 to which Pl6 (HA335) and Pl7 gave susceptibility. It is concluded that Pl5 and Pl8 are closely linked on linkage group 6 and form a separate resistance gene group from Pl6/Pl7 on linkage group 1. The origins of these groups of downy mildew resistance genes and their use in breeding are discussed.
TAG Theoretical and Applied Genetics, 2002
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. Specific primers were designed and used to amplify 13 markers covering a genetic distance of about 3 cM centred on the Pl6 locus. Cloning and sequence analysis of these 13 markers indicate that Pl6 contains conserved genes belonging to the TIR-NBS-LRR class of plant resistance genes.
Theoretical and Applied Genetics, 2003
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. Sequence comparison and Southern-blot analysis distinguished six classes of RGA. Two of these classes correspond to TIR-NBS-LRR sequences while the remaining four classes correspond to the non-TIR-NBS-LRR type of resistance genes. The genetic mapping of these RGAs on two segregating F2 populations showed that the non-TIR-NBS-LRR RGAs are clustered and linked to the Pl5/Pl8 locus for resistance to downy mildew in sunflower. These and other results indicate that different Pl loci conferring resistance to the same pathogen races may contain different sequences.