Analysis of powdery mildew resistance in the Spanish barley core collection

24 Pag., 4 Tabl., 2 Fig. The definitive version is available at: www3.interscience.wiley.comThe Spanish Barley Core Collection, consisting of one hundred and fifty-nine landrace-derived inbred lines and sixteen cultivars, was characterized for resistance to powdery mildew (Blumeria graminis f. sp. hordei) using a set of 27 isolates with a wide spectra of virulences/avirulences on most of the genes expected to occur in Europe. No landrace-derived line and no cultivar were resistant to all the isolates but at least three landraces showed infection types below 2 for 23 isolates. Twenty-two landraces and one cultivar showed resistance against half of the isolates used. Eleven isolates were sufficient to separate the majority of resistance profiles. In total, thirty-four resistance spectra were detected and fourteen resistance genes/alleles were postulated alone or in combination: MlLa, Mlh, Mlg, Mla22, Mla7(Mlu), Mla7(Mlk), Mlk, Mla12, Mla9, Mla3, Mla6(Mla14), Mlra and Mla1. The majority of resistance spectra are composed only by one line. Resistance in twenty-one landrace-derived lines and four cultivars was based on either unidentified genes or combinations of known and unknown genes/alleles. Therefore, the SBCC may be a source for broadening the genetic base of powdery mildew resistance.This research was funded by projects AGL2004-05311 and AGL2007-63625, granted by the Spanish Ministry of Science and Innovation. C.S. holds an I3P-Doc contract from CSIC. C.S. was supported by mobility fellowships from DFG, CSIC and Fundación Caja Inmaculada.Peer reviewe

Development of a cost-effective pyrosequencing approach for SNP genotyping in barley

12 Pag., 1 Tabl., 1 Fig. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-0523An improved, efficient, reliable and cost-effective pyrosequencing protocol for single nucleotide polymorphism (SNP) genotyping in plants is described. Labelling of the PCR products, required for the single-stranded pyrosequencing assay, is carried out in a one-step PCR with a universal biotinalyted M13 primer of 19-bp. A ratio of 1 : 10 of tailed primer to M13 primer in a 15-μl reaction volume turned out to be best suited for a successful identification of different alleles based on known SNPs. This technology allows cost-effective SNP genotyping in plant genomes for loci of interest at an overall low cost in a short period of time and is therefore best suited for marker-based selection procedures.This study was partially carried out within project AGL2007-63625, funded by the Spanish Ministry for Science and Innovation. C.S. holds an I3P contract from CSIC. C.S. was supported by mobility fellowships from the Deutsche Forschungsgemeinschaft (DFG), CSIC, Fundacion Caja Inmaculada and COST Action FA0604 (Tritigen).Peer reviewe

Resistance to powdery mildew in one Spanish barley landrace hardly resembles other previously identified wild barley resistances

23 Pags., 2 Tabls., 3 Figs. The definitive version is available at: http://link.springer.com/journal/10658wo major quantitative trait loci (QTLs) associated with resistance to powdery mildew (Blumeria graminis f. sp. hordei) were previously identified on chromosome 7H of the Spanish barley line SBCC097. The two QTLs seemed to share the same chromosomal position as the major genes mlt and Mlf, which were formerly described in Hordeum vulgare ssp. spontaneum-derived lines. In the present work, different lines that carry mlt (RS42-6*O), Mlf (RS137-28*E), or a combination of both (SI-4 and SI-6) were compared with SBCC097 to evaluate their relatedness at the phenotypic, cellular, and genetic levels. The resistance of the lines was characterised by inoculating them with a set of 27 isolates of B. graminis, which displayed a wide range of virulence. It was revealed that SBCC097 possessed a distinctive resistance spectrum. Microscopic assessment of the cytological development of the resistance response showed that SBCC097 clearly formed fewer well-established colonies and secondary hyphae than the other lines. This was confirmed by the infection type recorded after visual inspection. Genetic analyses of all five lines, based on markers flanking the QTLs derived from SBCC097, supported the macroscopic and microscopic data and pointed to the presence of a combination of novel genes or alleles in SBCC097, which may be included in the category of “intermediate-acting” genes, governing resistance mainly at the post-penetration stage.C.S. held a mobility fellowship from the University of Coruña. Part of the results were obtained within the project ExpResBar funded by the German Federal Ministry of Education and Research under grant number 0315702B within the KBBE-II call, and by the Spanish Ministry of Science and Innovation, grant number EUI2009-04075.Peer reviewe

Development of diagnostic markers and physical mapping for the Rrs1 resistance locus against scald

Rhynchosporium secalis, the causal agent of scald, is still one of the most important foliar diseases of barley. Its high genetic variability and recombination frequency enable it to rapidly overcome monogenic resistances. To date four major scald resistance genes have been identified in cultivated barley (Hordeum vulgare ssp. vulgare), and another four in wild barley (Hv. spontaneum or Hv. bulbosum). The most abundant and effective one is the Rrsl resistance locus, mapping near the centromeric region of chromosome 3H. Aim of the project is the fine mapping of the Rrsl locus and the development of diagnostic markers.This project was funded by the GABI-Plant-KBBE II Project, ExpResBar” under the grant 0315702C and the StMELF.Peer Reviewe

Identification of quantitative trait loci for resistance to powdery mildew in a Spanish barley landrace

30 Pag., 1 Tabl., 5 Fig. The definitive version is available at: http://www.springerlink.com/content/1380-3743/The Spanish landrace-derived inbred line SBCC97, together with other lines from the Spanish Barley Core Collection, displays high resistance to powdery mildew, caused by the fungus Blumeria graminis f. sp. hordei. The objective of this study was to map quantitative trait loci (QTLs) for resistance to powdery mildew in a recombinant inbred line population derived from a cross between SBCC97 and the susceptible cultivar ‘Plaisant’. Phenotypic analysis was performed using four B. graminis isolates, and genetic maps were constructed with mainly simple sequence repeat (SSR) markers, following a sequential genotyping strategy. Two major QTLs with large effects were identified on chromosome 7H, and they accounted for up to 45% of the total phenotypic variance. The alleles for resistance at each QTL were contributed by the Spanish parent SBCC97. One locus was mapped to the short arm of chromosome 7HS, and was flanked by the resistance gene analogue (RGA) marker S9202 and the SSR GBM1060. This corresponded to the same chromosomal region in which a major race-specific resistance gene from Hordeum vulgare ssp. spontaneum, designated as mlt, had been identified previously. The second QTL was linked tightly to marker EBmac0755, and it shared its chromosomal location with the qualitative resistance gene Mlf, which has only been described previously in the wild ancestor H. spontaneum. This is the first report of these two QTLs occurring together in cultivated barley, and it paves the way for their use in barley breeding programs that are designed to transfer resistance alleles into elite cultivars.This work was supported by the Spanish Ministry of Education and Research (Project AGL2007-63625), and by the European Regional Development Fund. C.S. holds an I3P contract from CSIC. H.D. was supported by a Masters fellowship from IAMZ-CIHEAM.Peer reviewe

The Rrs1 locus and resistance against scald in barley.

Scald, caused by Rhynchosporium commune (formerly R. secalis ), is one of the most prevalent barley diseases worldwide. To date, four major scald resistance genes have been mapped in cultivated barley ( Hordeum vulgare ssp. vulgare ), and another four in wild barley ( Hv. spontaneum ) or Hv. bulbosum . The most abundant and effective one is the Rrs1 resistanc e locus, formerly known as Rh - Rh3Rh4 locus. It was mapped to the centromeric region of chromosome 3H. However, it is still not clear whether Rrs1 is a collection of several R - genes close to each other or several alleles of the same gene. A search for new r esistance sources revealed that Spanish landrace - derived lines SBCC145 and SBCC154 showed outstanding resistance to scald. To analyze the genetic basis in more detail two large DH mapping populations were developed crossing each donor line with cv. Beatrix . A large QTL in the centromeric region of chromosome 3H was found in both populations phenotyped for scald resistance in a well - established greenhouse test, therefore, confirmed this locus as the only resistance locus in both populations. To confirm and e nclose this locus, the “ Rrs1 region” has been saturated with all available SSR and SNP - markers and a consensus map was constructed. New markers for this region are developed based on the lllumina iSelect custom 9K barley chip, the barley genome zipper and a BSA analysis with AFLP. The genome zipper identified several candidate genes. Because of a low gene/cM density, an enrichment of candidate sequences in the region of Rrs1 is done by a BSTA (bulked segregant transcriptome analysis) with four normalized cD NA libraries and Illumina HiSeq in combination with a high resolution mapping program. For fine mapping and haplotyping of all the genes around the Rrs1 loci a mapping population comprising >10,000 F 2 from the cross SBCC145 x Beatrix has been constructed. F 2 screening of about 11,000 lines to select recombinant lines between two flanking markers has identified around 442 verified recombinant plants. The effective Rrs1 allele found and the closely linked markers developed are already useful tools for molecul ar breeding programs.Peer Reviewe

The Rrs1 resistance locus against scald in barley

Scald, caused by Rhynchosporium commune, is one of the most prevalent barley diseases worldwide. To date, four major scald resistance genes have been mapped in cultivated barley (Hordeum vulgare ssp. vulgare), and another four in wild barley (Hv. Spontaneum) or Hv. bulbosum. The most abundant and effective one is the Rrs1 resistance locus, which was mapped to the centromeric region of chromosome 3H. However, it is still not clear whether Rrs1 formerly known as Rh-Rh3Rh4 locus is a collection of several R-genes close to each other or several alleles of the same gene. A search for new resistance sources revealed that Spanish landrace-derived lines SBCC145 and SBCC154 showed outstanding resistance to scald. To analyze the genetic basis in more detail two large DH mapping populations were developed crossing each donor line with cv. Beatrix. A large QTL in the centromeric region of chromosome 3H was found in both populations, therefore, suggesting this locus as the only resistance locus in both populations. To confirm and enclose this locus, the “Rrs1 region” has been saturated with all available SSR and SNP-markers and a consensus map was constructed. New markers for this region are developed based on the lllumina iSelect custom 9K barley chip and candidate genes derived from the barley genome zipper. Because of a low gene/cM density, an enrichment of candidate sequences in the region of Rrs1 is done by a BSTA (bulked segregant transcriptome analysis) with four normalized cDNA libraries and Illumina HiSeq in combination with a high resolution mapping program. For fine mapping and haplotyping a mapping population comprising >10,000 F2 from the cross SBCC145 x Beatrix has been constructed. F2 screening of about 11,000 lines to select recombinant lines between two flanking markers has identified around 442 verified recombinant plants. The effective Rrs1 allele found and the closely linked markers developed are already useful tools for molecular breeding programs.Peer Reviewe

Assessing genetic and phenotypic diversity in pepper (Capsicum annuum L.) landraces from North-West Spain

43 Pags.- 5 Tabls.- 3 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/03044238Pepper (Capsicum annuum L.) is one of the most valuable vegetables in the world. Over the last decades, highly performing cultivars have progressively replaced the diversified and heterogeneous landraces worldwide, causing wide genetic erosion in this crop. The recovery of these ancient landraces, which might preserve alleles of agricultural interest and local adaptations, results of pivotal importance for the development of new varieties and the maintenance of a sustainable agriculture. In the present work, a collection of twenty-six landrace-derived inbred lines and three landraces from North-West Spain were evaluated for their agronomic performance and genetic diversity based on a set of twenty-seven morphological descriptors and twenty microsatellite markers. The collection featured phenotypic variability for all the studied traits, which were influenced by the location, except for the yield. The principal component analysis divided the landraces in well-defined groups, with only Arnoia, Punxin and Blanco Rosal showing some degree of overlapping. The greater part of the variance was accounted for traits such as fruit weight, pericarp thickness and fruit shape and color. The molecular analyses suggested a high level of genetic diversity within the collection and the presence of specific alleles, which were not previously detected in other Spanish pepper landraces. Multivariate and Bayesian clustering showed that landraces were primarily grouped according to their geographical origin and secondarily in agreement with the characteristics of their fruits. Six groups of landraces, with a great genetic differentiation, were clearly identified. Only the landraces Mougan and Arnoia possessed an allele associated to the pungency character.This work was supported by Xunta de Galicia (Project EM2014/048) and by the Spanish Institute for Agricultural and Food Research and Technology (INIA), co-financed by the European Regional Development Fund (FEDER) (Project RTA2011–00118–C02–02).Peer reviewe

Screening the Spanish Barley Core Collection for disease resistance

26 Pag., 6 Tabl. The definitive version is available at: www3.interscience.wiley.comThe Spanish Barley Core Collection comprises 159 landrace-derived inbred lines and 16 cultivars adapted to Southern European conditions. The collection was screened for resistance to powdery mildew (Blumeria graminis), scald (Rhynchosporium secalis), leaf rust (Puccinia hordei), net blotch (Pyrenophora teres f. teres), Barley yellow dwarf virus (BYDV) and Barley mild mosaic virus (BaMMV). Resistance to powdery mildew was outstanding, with 58 lines presenting mean overall resistance, among them seven landrace-derived lines resistant to all seven isolates tested. About 26% of the Spanish lines were resistant to scald. Resistance to leaf rust and to net blotch was scarce, though a few accessions showed resistance levels as good as the checks. Thirteen accessions (12 Spanish) were totally resistant to BaMMV and c. 20% of accessions showed moderate tolerance to BYDV. Landrace-derived lines from the Mediterranean Coast and Southern regions of Spain were the most resistant to powdery mildew and leaf rust, but the most susceptible to viruses. Potential sources of resistance might be preserved in some accessions subjected to selective pressure in the region of origin.This study was funded by projects RTA01-088-C3, granted by the INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentación), of the Spanish Ministry of Science and Technology, projects AGL2004-05311/AGR, AGL2007-63625, all of them co-funded by the European Regional Development Fund and the Bavarian Ministry of Agriculture and Forest/Bayerisches Staatsministerium für Landwirtschaft und Forsten.Peer reviewe