ORCID Profile
0000-0002-4820-2846
Current Organisation
Technical University of Munich
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Publisher: Springer Science and Business Media LLC
Date: 27-10-2011
Abstract: Frost is an important abiotic stress that limits cereal production in the temperate zone. As the most frost tolerant small grain cereal, rye ( Secale cereale L.) is an ideal cereal model for investigating the genetic basis of frost tolerance (FT), a complex trait with polygenic inheritance. Using 201 genotypes from five Eastern and Middle European winter rye populations, this study reports a multi-platform candidate gene-based association analysis in rye using 161 single nucleotide polymorphisms (SNPs) and nine insertion-deletion (Indel) polymorphisms previously identified from twelve candidate genes with a putative role in the frost responsive network. Phenotypic data analyses of FT in three different phenotyping platforms, controlled, semi-controlled and field, revealed significant genetic variations in the plant material under study. Statistically significant ( P 0.05) associations between FT and SNPs/haplotypes of candidate genes were identified. Two SNPs in ScCbf15 and one in ScCbf12 , all leading to amino acid exchanges, were significantly associated with FT over all three phenotyping platforms. Distribution of SNP effect sizes expressed as percentage of the genetic variance explained by in idual SNPs was highly skewed towards zero with a few SNPs obtaining large effects. Two-way epistasis was found between 14 pairs of candidate genes. Relatively low to medium empirical correlations of SNP-FT associations were observed across the three platforms underlining the need for multi-level experimentation for dissecting complex associations between genotypes and FT in rye. Candidate gene based-association studies are a powerful tool for investigating the genetic basis of FT in rye. Results of this study support the findings of bi-parental linkage mapping and expression studies that the Cbf gene family plays an essential role in FT.
Publisher: Cold Spring Harbor Laboratory
Date: 19-09-2017
DOI: 10.1101/190728
Abstract: In plant-pathogen interactions, components of the plant ubiquitination machinery are preferred targets of pathogen-encoded effectors suppressing defense responses or co-opting host cellular functions for accommodation. Here, we employed transient and stable gene silencing-and over-expression systems in Hordeum vulgare (barley) to study the function of HvARM1 (for H. vulgare Armadillo 1 ), a partial gene duplicate of the U-box/armadillo-repeat E3 ligase Hv PUB15 (for H. vulgare Plant U-Box 15 ). The partial ARM1 gene was derived from an ancient gene-duplication event in a common ancestor of the Triticeae tribe of grasses comprising the major crop species H. vulgare , Triticum aestivum and Secale cereale . The barley gene HvARM1 contributed to quantitative host as well as nonhost resistance to the biotrophic powdery mildew fungus Blumeria graminis , and allelic variants were found to be associated with powdery mildew-disease severity. Both HvPUB15 and HvARM1 proteins interacted in yeast and plant cells with the susceptibility-related, plastid-localized barley homologs of THF1 (for Thylakoid formation 1) and of ClpS1 (for Clp-protease adaptor S1) of Arabidopsis thaliana . The results suggest a neo-functionalization HvARM1 to increase resistance against powdery mildew and provide a link to plastid function in susceptibility to biotrophic pathogen attack.
Publisher: Springer Science and Business Media LLC
Date: 18-03-2021
DOI: 10.1038/S41588-021-00807-0
Abstract: Rye ( Secale cereale L.) is an exceptionally climate-resilient cereal crop, used extensively to produce improved wheat varieties via introgressive hybridization and possessing the entire repertoire of genes necessary to enable hybrid breeding. Rye is allogamous and only recently domesticated, thus giving cultivated ryes access to a erse and exploitable wild gene pool. To further enhance the agronomic potential of rye, we produced a chromosome-scale annotated assembly of the 7.9-gigabase rye genome and extensively validated its quality by using a suite of molecular genetic resources. We demonstrate applications of this resource with a broad range of investigations. We present findings on cultivated rye’s incomplete genetic isolation from wild relatives, mechanisms of genome structural evolution, pathogen resistance, low-temperature tolerance, fertility control systems for hybrid breeding and the yield benefits of rye–wheat introgressions.
Publisher: Springer Science and Business Media LLC
Date: 28-09-2011
Abstract: The improvement of agricultural crops with regard to yield, resistance and environmental adaptation is a perpetual challenge for both breeding and research. Exploration of the genetic potential and implementation of genome-based breeding strategies for efficient rye ( Secale cereale L.) cultivar improvement have been h ered by the lack of genome sequence information. To overcome this limitation we sequenced the transcriptomes of five winter rye inbred lines using Roche/454 GS FLX technology. More than 2.5 million reads were assembled into 115,400 contigs representing a comprehensive rye expressed sequence tag (EST) resource. From sequence comparisons 5,234 single nucleotide polymorphisms (SNPs) were identified to develop the Rye5K high-throughput SNP genotyping array. Performance of the Rye5K SNP array was investigated by genotyping 59 rye inbred lines including the five lines used for sequencing, and five barley, three wheat, and two triticale accessions. A balanced distribution of allele frequencies ranging from 0.1 to 0.9 was observed. Residual heterozygosity of the rye inbred lines varied from 4.0 to 20.4% with higher average heterozygosity in the pollen compared to the seed parent pool. The established sequence and molecular marker resources will improve and promote genetic and genomic research as well as genome-based breeding in rye.
Publisher: Springer Science and Business Media LLC
Date: 24-06-2006
DOI: 10.1007/S00122-006-0330-2
Abstract: Bacterial wilt caused by Xanthomonas translucens pv. graminis (Xtg) is a major disease of economically important forage crops such as ryegrasses and fescues. Targeted breeding based on seedling inoculation has resulted in cultivars with considerable levels of resistance. However, the mechanisms of inheritance of resistance are poorly understood and further breeding progress is difficult to obtain. This study aimed to assess the relevance of the seedling screening in the glasshouse for adult plant resistance in the field and to investigate genetic control of resistance to bacterial wilt in Italian ryegrass (Lolium multiflorum Lam.). A mapping population consisting of 306 F1 in iduals was established and resistance to bacterial wilt was assessed in glasshouse and field experiments. Highly correlated data (r = 0.67-0.77, P < 0.01) between trial locations demonstrated the suitability of glasshouse screens for phenotypic selection. Analysis of quantitative trait loci (QTL) based on a high density genetic linkage map consisting of 368 lified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers revealed a single major QTL on linkage group (LG) 4 explaining 67% of the total phenotypic variance (Vp). In addition, a minor QTL was observed on LG 5. Field experiments confirmed the major QTL on LG 4 to explain 43% (in 2004) to 84% (in 2005) of Vp and also revealed additional minor QTLs on LG 1, LG 4 and LG 6. The identified QTLs and the closely linked markers represent important targets for marker-assisted selection of Italian ryegrass.
Publisher: Cold Spring Harbor Laboratory
Date: 12-12-2019
DOI: 10.1101/2019.12.11.869693
Abstract: We present a chromosome-scale annotated assembly of the rye ( Secale cereale L. inbred line ‘Lo7’) genome, which we use to explore Triticeae genomic evolution, and rye’s superior disease and stress tolerance. The rye genome shares chromosome-level organization with other Triticeae cereals, but exhibits unique retrotransposon dynamics and structural features. Crop improvement in rye, as well as in wheat and triticale, will profit from investigations of rye gene families implicated in pathogen resistance, low temperature tolerance, and fertility control systems for hybrid breeding. We show that rye introgressions in wheat breeding panels can be characterised in high-throughput to predict the yield effects and trade-offs of rye chromatin.
Publisher: Springer Science and Business Media LLC
Date: 11-04-2007
DOI: 10.1007/S00122-007-0535-Z
Abstract: Crown rust, caused by Puccinia coronata f. sp. lolii, is one of the most important diseases of temperate forage grasses, such as ryegrasses (Lolium spp.), affecting yield and nutritional quality. Therefore, resistance to crown rust is a major goal in ryegrass breeding programmes. In a two-way pseudo-testcross population consisting of 306 Lolium multiflorum in iduals, multisite field evaluations as well as alternative methods based on artificial inoculation with natural inoculate in controlled environments were used to identify QTLs controlling resistance to crown rust. Disease scores obtained from glasshouse and leaf segment test (LST) evaluations were highly correlated with scores from a multisite field assessment (r = 0.66 and 0.79, P < 0.01, respectively) and thus confirmed suitability of these methods for crown rust investigations. Moreover, QTL mapping based on a linkage map consisting of 368 lified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers revealed similar results across different phenotyping methods. Two major QTLs were consistently detected on linkage group (LG) 1 and LG 2, explaining up to 56% of total phenotypic variance (V (p)). Nevertheless, differences between position and magnitude of QTLs were observed among in idual field locations and suggested the existence of specific local pathogen populations. The present study not only compared QTL results among crown rust evaluation methods and environments, but also identified molecular markers closely linked to previously undescribed QTLs for crown rust resistance in Italian ryegrass with the potential to be applied in marker-assisted forage crop breeding.
Publisher: Springer Science and Business Media LLC
Date: 10-01-2011
Abstract: Rye ( Secale cereale L.) is the most frost tolerant cereal species. As an outcrossing species, rye exhibits high levels of intraspecific ersity, which makes it well-suited for allele mining in genes involved in the frost responsive network. For investigating genetic ersity and the extent of linkage disequilibrium (LD) we analyzed eleven candidate genes and 37 microsatellite markers in 201 lines from five Eastern and Middle European rye populations. A total of 147 single nucleotide polymorphisms (SNPs) and nine insertion-deletion polymorphisms were found within 7,639 bp of DNA sequence from eleven candidate genes, resulting in an average SNP frequency of 1 SNP/52 bp. Nucleotide and haplotype ersity of candidate genes were high with average values π = 5.6 × 10 -3 and Hd = 0.59, respectively. According to an analysis of molecular variance (AMOVA), most of the genetic variation was found between in iduals within populations. Haplotype frequencies varied markedly between the candidate genes. ScCbf14 , ScVrn1 , and ScDhn1 were dominated by a single haplotype, while the other 8 genes ( ScCbf2 , ScCbf6 , ScCbf9b , ScCbf11 , ScCbf12 , ScCbf15 , ScIce2 , and ScDhn3 ) had a more balanced haplotype frequency distribution. Intra-genic LD decayed rapidly, within approximately 520 bp on average. Genome-wide LD based on microsatellites was low. The Middle European population did not differ substantially from the four Eastern European populations in terms of haplotype frequencies or in the level of nucleotide ersity. The low LD in rye compared to self-pollinating species promises a high resolution in genome-wide association mapping. SNPs discovered in the promoters or coding regions, which attribute to non-synonymous substitutions, are suitable candidates for association mapping.
Publisher: Springer Science and Business Media LLC
Date: 18-11-2004
DOI: 10.1007/S00122-004-1832-4
Abstract: Soil-borne barley yellow mosaic virus disease--caused by a complex of at least three viruses, i.e. Barley mild mosaic virus (BaMMV), Barley yellow mosaic virus (BaYMV) and BaYMV-2--is one of the most important diseases of winter barley in Europe. The two genes rym4, effective against BaMMV and BaYMV, and rym5, additionally effective against BaYMV-2, comprise a complex locus on chromosome 3HL, which is of special importance to European barley breeding. To provide the genetic basis for positional cloning of the Rym4/Rym5 locus, two high-resolution maps were constructed based on co-dominant flanking markers (MWG838/Y57c10 - MWG010/Bmac29). Mapping at a resolution of about 0.05% rec., rym4 has been located 1.07% recombination distal of marker MWG838 and 1.21% recombination proximal to marker MWG010. Based on a population size of 3,884 F2 plants (0.013% recombination) the interval harbouring rym5 was delimited to 1.49+/-0.14% recombination. By testing segmental recombinant inbred lines (RILs) for reaction to the different viruses at a resolution of 0.05% rec. (rym4) and 0.019% rec. (rym5), no segregation concerning the reaction to the different viruses could be observed. AFLP-based marker saturation for rym4, using 932 PstI+2/MseI+3 primer combinations only resulted in three markers with the closest one linked at 0.9% recombination to the gene. Two of these markers detected epialleles arising from the differential cytosine methylation of PstI sites. Regarding rym5, profiling of 1,200 RAPD primers (about 18,000 loci) and 2,048 EcoRI+3/MseI+3 AFLP primer combinations (about 205,000 loci) resulted in one RAPD marker and seven AFLP markers tightly linked to the resistance gene. Flanking markers with the closest linkage to rym5 (0.05% and 0.88% recombination) were converted into STS markers. These markers provide a starting point for chromosomal walking and may be exploited in marker-assisted selection for virus resistance based on rym5.
Publisher: Oxford University Press (OUP)
Date: 10-2013
Publisher: Proceedings of the National Academy of Sciences
Date: 30-07-2012
Abstract: Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic elements comparable to selfish DNA, like transposons. In contrast to transposons, they are autonomously inherited independent of the host genome and have their own mechanisms of mitotic or meiotic drive. Although B chromosomes were first described a century ago, little is known about their origin and molecular makeup. The widely accepted view is that they are derived from fragments of A chromosomes and/or generated in response to interspecific hybridization. Through next-generation sequencing of sorted A and B chromosomes, we show that B chromosomes of rye are rich in gene-derived sequences, allowing us to trace their origin to fragments of A chromosomes, with the largest parts corresponding to rye chromosomes 3R and 7R. Compared with A chromosomes, B chromosomes were also found to accumulate large amounts of specific repeats and insertions of organellar DNA. The origin of rye B chromosomes occurred an estimated ∼1.1–1.3 Mya, overlapping in time with the onset of the genus Secale (1.7 Mya). We propose a comprehensive model of B chromosome evolution, including its origin by recombination of several A chromosomes followed by capturing of additional A-derived and organellar sequences and lification of B-specific repeats.
Location: Germany
Location: Germany
No related grants have been discovered for Eva Bauer.