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Guoping Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Association mapping for total polyphenol content, total flavonoid content and antioxidant activity in Barley
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Zhigang Han, Shengguan Cai, Jingjie Zhang, Xiaohui Chen, Xiaoyan Quan, Guoping Zhang
    Abstract:

    Abstract Background The interest has been increasing on the phenolic compounds in plants because of their nutritive function as food and the roles regulating plant growth. However, their underlying genetic mechanism in Barley is still not clear. Results A genome-wide association study (GWAS) was conducted for total phenolic content (TPC), total flavonoid content (FLC) and antioxidant activity (AOA) in 67 cultivated and 156 Tibetan wild Barley genotypes. Most markers associated with phenolic content were different in cultivated and wild Barleys. The markers bPb-0572 and bPb-4531 were identified as the major QTLs controlling phenolic compounds in Tibetan wild Barley. Moreover, the marker bPb-4531 was co-located with the UDP- glycosyltransferase gene (HvUGT), which is a homolog to Arabidopsis UGTs and involved in biosynthesis of flavonoid glycosides . Conclusions GWAS is an efficient tool for exploring the genetic architecture of phenolic compounds in the cultivated and Tibetan wild Barleys. The DArT markers applied in this study can be used in Barley breeding for developing new Barley cultivars with higher phenolics content. The candidate gene (HvUGT) provides a potential route for deep understanding of the molecular mechanism of flavonoid synthesis

  • metabolite profiling of Barley grains subjected to water stress to explain the genotypic difference in drought induced impacts on malting quality
    Frontiers in Plant Science, 2017
    Co-Authors: Kangfeng Cai, Guoping Zhang, Fanrong Zeng
    Abstract:

    Grain weight and protein content will be reduced and increased respectively when Barley is subjected to water stress after anthesis, consequently deteriorating the malt quality. However such adverse impact of water stress differs greatly among Barley genotypes. In this study, two Tibetan wild Barley accessions and two cultivated varieties differing in water stress tolerance, were used to investigate the genotypic difference in metabolic profiles during grain-filling stage under drought condition. Totally 71 differently-accumulated metabolites were identified, including organic acids, amino acids / amines, and sugars / sugar alcohols. Their relative contents were significantly affected by water stress for all genotypes and differed distinctly between the wild and cultivated Barleys. The PCA analysis of metabolites indicated that the Tibetan wild Barley XZ147 possessed a unique response to water stress. When subjected to water stress, the wild Barley XZ147 showed the most increase of β-amylase activity among the four genotypes, as a result of its higher lysine content, less IAA biosynthesis, more stable H2O2 homeostasis and more up-regulation of BMY1 gene. On the other hand, XZ147 had the most reduction of β-glucan content under water stress than the other genotypes, which could be explained by the faster grain filling process and the less expression of β-glucan synthase gene GSL7. All these results indicated a great potential for XZ147 in Barley breeding for improving water stress tolerance.

  • development and characterization of polymorphic est ssr and genomic ssr markers for tibetan annual wild Barley
    PLOS ONE, 2014
    Co-Authors: Mian Zhang, Weihua Mao, Guoping Zhang
    Abstract:

    Tibetan annual wild Barley is rich in genetic variation. This study was aimed at the exploitation of new SSRs for the genetic diversity and phylogenetic analysis of wild Barley by data mining. We developed 49 novel EST-SSRs and confirmed 20 genomic SSRs for 80 Tibetan annual wild Barley and 16 cultivated Barley accessions. A total of 213 alleles were generated from 69 loci with an average of 3.14 alleles per locus. The trimeric repeats were the most abundant motifs (40.82%) among the EST-SSRs, while the majority of the genomic SSRs were di-nuleotide repeats. The polymorphic information content (PIC) ranged from 0.08 to 0.75 with a mean of 0.46. Besides this, the expected heterozygosity (He) ranged from 0.0854 to 0.7842 with an average of 0.5279. Overall, the polymorphism of genomic SSRs was higher than that of EST-SSRs. Furthermore, the number of alleles and the PIC of wild Barley were both higher than that of cultivated Barley, being 3.12 vs 2.59 and 0.44 vs 0.37. Indicating more polymorphism existed in the Tibetan wild Barley than in cultivated Barley. The 96 accessions were divided into eight subpopulations based on 69 SSR markers, and the cultivated genotypes can be clearly separated from wild Barleys. A total of 47 SSR-containing EST unigenes showed significant similarities to the known genes. These EST-SSR markers have potential for application in germplasm appraisal, genetic diversity and population structure analysis, facilitating marker-assisted breeding and crop improvement in Barley.

  • genome wide association analysis of aluminum tolerance in cultivated and tibetan wild Barley
    PLOS ONE, 2013
    Co-Authors: Shengguan Cai, Yuqing Huang, Yechang Huang, Zahra Jabeen, Guoping Zhang
    Abstract:

    Tibetan wild Barley (Hordeum vulgare L. ssp. spontaneum), originated and grown in harsh enviroment in Tibet, is well-known for its rich germpalsm with high tolerance to abiotic stresses. However, the genetic variation and genes involved in Al tolerance are not totally known for the wild Barley. In this study, a genome-wide association analysis (GWAS) was performed by using four root parameters related with Al tolerance and 469 DArT markers on 7 chromosomes within or across 110 Tibetan wild accessions and 56 cultivated cultivars. Population structure and cluster analysis revealed that a wide genetic diversity was present in Tibetan wild Barley. Linkage disequilibrium (LD) decayed more rapidly in Tibetan wild Barley (9.30 cM) than cultivated Barley (11.52 cM), indicating that GWAS may provide higher resolution in the Tibetan group. Two novel Tibetan group-specific loci, bpb-9458 and bpb-8524 were identified, which were associated with relative longest root growth (RLRG), located at 2H and 7H on barely genome, and could explain 12.9% and 9.7% of the phenotypic variation, respectively. Moreover, a common locus bpb-6949, localized 0.8 cM away from a candidate gene HvMATE, was detected in both wild and cultivated Barleys, and showed significant association with total root growth (TRG). The present study highlights that Tibetan wild Barley could provide elite germplasm novel genes for Barley Al-tolerant improvement.

  • tibet is one of the centers of domestication of cultivated Barley
    Proceedings of the National Academy of Sciences of the United States of America, 2012
    Co-Authors: Dezhi Wu, Avigdor Beiles, Jordi Comadran, Guoxiong Chen, Zhonghua Chen, Meixue Zhou, Guoping Zhang
    Abstract:

    The Near East Fertile Crescent is well recognized as a primary center of Barley origin, diversity, and domestication. A large number of wild Barleys have been collected from the Tibetan Plateau, which is characterized by an extreme environment. We used genome-wide diversity array technology markers to analyze the genotypic division between wild Barley from the Near East and Tibet. Our results confirmed the existence of Tibetan wild Barley and suggested that the split between the wild Barleys in the Near East and those in Tibet occurred around 2.76 million years ago (Mya). To test the concept of polyphyletic domestication of Barley, we characterized a set of worldwide cultivated Barley. Some Chinese hulless and six-rowed Barleys showed a close relationship with Tibetan wild Barley but showed no common ancestor with other cultivated Barley. Our data support the concept of polyphyletic domestication of cultivated Barley and indicate that the Tibetan Plateau and its vicinity is one of the centers of domestication of cultivated Barley. The current results may be highly significant in exploring the elite germplasm for Barley breeding, especially against cold and drought stresses.

Roger P Wise - One of the best experts on this subject based on the ideXlab platform.

  • The knottin-like Blufensin family regulates genes involved in nuclear import and the secretory pathway in Barley-powdery mildew interactions.
    Frontiers in plant science, 2015
    Co-Authors: Yan Meng, Priyanka Surana, Greg Fuerst, Dan Nettleton, Roger P Wise
    Abstract:

    Plants have evolved complex regulatory mechanisms to control a multi-layered defense response to microbial attack. Both temporal and spatial gene expression are tightly regulated in response to pathogen ingress, modulating both positive and negative control of defense. BLUFENSINs, small knottin-like peptides in Barley, wheat, and rice, are highly induced by attack from fungal pathogens, in particular, the obligate biotrophic fungus, Blumeria graminis f. sp. hordei (Bgh), causal agent of Barley powdery mildew. Previous research indicated that Blufensin1 (Bln1) functions as a negative regulator of basal defense mechanisms. In the current report, we show that BLN1 and BLN2 can both be secreted to the apoplast and Barley stripe mosaic virus (BSMV)-mediated overexpression of Bln2 increases susceptibility of Barley to Bgh. Bimolecular fluorescence complementation (BiFC) assays signify that BLN1 and BLN2 can interact with each other, and with calmodulin. We then used BSMV-induced gene silencing to knock down Bln1, followed by Barley1 GeneChip transcriptome analysis, to identify additional host genes influenced by Bln1. Analysis of differential expression revealed a gene set enriched for those encoding proteins annotated to nuclear import and the secretory pathway, particularly Importin α1-b and Sec61 γ subunits. Further functional analysis of these two affected genes showed that when silenced, they also reduced susceptibility to Bgh. Taken together, we postulate that Bln1 is co-opted by Bgh to facilitate transport of disease-related host proteins or effectors, influencing the establishment of Bgh compatibility on its Barley host.

  • Drought response in the spikes of Barley: gene expression in the lemma, palea, awn, and seed
    Functional & Integrative Genomics, 2010
    Co-Authors: Tilahun Abebe, Kalpalatha Melmaiee, Virginia Berg, Roger P Wise
    Abstract:

    The photosynthetic organs of the Barley spike (lemma, palea, and awn) are considered resistant to drought. However, there is little information about gene expression in the spike organs under drought conditions. We compared response of the transcriptome of the lemma, palea, awn, and seed to drought stress using the Barley1 Genome Array. Barley plants were exposed to drought treatment for 4 days at the grain-filling stage by withholding water. At the end of the stress, relative water content of the lemma, palea, and awn dropped from 85% to 60%. Nevertheless, the water content of the seed only decreased from 89% to 81%. Transcript abundance followed the water status of the spike organs; the awn had more drought-regulated genes followed by lemma and palea, and the seed showed very little change in gene expression. Despite expressing more drought-associated genes, many genes for amino acid, amino acid derivative, and carbohydrate metabolism, as well as for photosynthesis, respiration, and stress response, were down-regulated in the awn compared with the lemma, palea, and seed. This suggests that the lemma and the palea are more resistant to drought stress compared with the awn.

  • exploiting regulatory variation to identify genes underlying quantitative resistance to the wheat stem rust pathogen puccinia graminis f sp tritici in Barley
    Theoretical and Applied Genetics, 2008
    Co-Authors: Arnis Druka, Brian J. Steffenson, David Marshall, Timothy J Close, Ling Zhang, Elena Potokina, Zewei Luo, Nicola Bonar, Ilze Druka, Roger P Wise
    Abstract:

    We previously mapped mRNA transcript abundance traits (expression-QTL or eQTL) using the Barley1 Affymetrix array and ‘whole plant’ tissue from 139 progeny of the Steptoe × Morex (St/Mx) reference Barley mapping population. Of the 22,840 probesets (genes) on the array, 15,987 reported transcript abundance signals that were suitable for eQTL analysis, and this revealed a genome-wide distribution of 23,738 significant eQTLs. Here we have explored the potential of using these mRNA abundance eQTL traits as surrogates for the identification of candidate genes underlying the interaction between Barley and the wheat stem rust fungus Puccinia graminis f. sp. tritici. We re-analysed quantitative ‘resistance phenotype’ data collected on this population in 1990/1991 and identified six loci associated with Barley’s reaction to stem rust. One of these coincided with the major stem rust resistance locus Rpg1, that we had previously positionally cloned using this population. Correlation analysis between phenotype values for rust infection and mRNA abundance values reported by the 22,840 GeneChip probe sets placed Rpg1, which is on the Barley1 GeneChip, in the top five candidate genes for the major QTL on chromosome 7H corresponding to the location of Rpg1. A second co-located with the rpg4/Rpg5 stem rust resistance locus that has been mapped in a different population and the remaining four were novel. Correlation analyses identified candidate genes for the rpg4/Rpg5 locus on chromosome 5H. By combining our data with additional published mRNA profiling data sets, we identify a putative sensory transduction histidine kinase as a strong candidate for a novel resistance locus on chromosome 2H and compile candidate gene lists for the other three loci.

  • diversification of lrk tak kinase gene clusters is associated with subfunctionalization and cultivar specific transcript accumulation in Barley
    Functional & Integrative Genomics, 2008
    Co-Authors: Pingsha Hu, Roger P Wise
    Abstract:

    Lrk (Lr10 receptor-like kinase) and Tak (Triticum aestivum kinase) belong to the receptor-like kinase (RLK) supergene family in higher plants. Three Lrk/Tak gene regions spanning greater than 600 kb were identified via a genome-wide survey of Barley gene-rich BAC clones. Two Lrk/Tak gene clusters are positioned on Barley chromosome 3 (3H) and another is localized on chromosome 5 (1H), with each Lrk and Tak open reading frame physically positioned in a back-to-back orientation. Thirteen new Lrk/Tak-like fragments were cloned from the two clusters on 3H and the single cluster on 1H, respectively, and compared phylogenetically with other grass Lrk/Tak-like genes, including a 280-kb Lrk/Tak cluster on rice chromosome 1S. Physically clustered Lrk/Tak-like genes always form monophyletic groups; this suggests that the primary mechanism of expansion of the Lrk/Tak RLK super family was by tandem duplication, of which most members were duplicated after speciation of the Poaceae. Cultivar-dependent transcript accumulation of some Lrk/Tak family members on 3H, as revealed via Barley1 GeneChip microarray analysis, is consistent with the hypothesis of subfunctionalization of Lrk/Tak members following tandem duplication.

Andreas Graner - One of the best experts on this subject based on the ideXlab platform.

  • sequence diversification in recessive alleles of two host factor genes suggests adaptive selection for bymovirus resistance in cultivated Barley from east asia
    Theoretical and Applied Genetics, 2017
    Co-Authors: Ping Yang, Bernhard J. Hofinger, Kostya Kanyuka, Frank Ordon, Andreas Graner, Benjamin Kilian, Antje Habekus, Nils Stein
    Abstract:

    Two distinct patterns of sequence diversity for the recessive alleles of two host factors HvPDIL5 - 1 and HvEIF4E indicated the adaptive selection for bymovirus resistance in cultivated Barley from East Asia. Plant pathogens are constantly challenging plant fitness and driving resistance gene evolution in host species. Little is known about the evolution of sequence diversity in host recessive resistance genes that interact with plant viruses. Here, by combining previously published and newly generated targeted re-sequencing information, we systematically analyzed natural variation in a broad collection of wild (Hordeum spontaneum; Hs) and domesticated Barleys (Hordeum vulgare; Hv) using the full-length coding sequence of the two host factor genes, HvPDIL5-1 and HvEIF4E, conferring recessive resistance to the agriculturally important Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV). Interestingly, two types of gene evolution conferred by sequence variation in domesticated Barley, but not in wild Barley were observed. Whereas resistance-conferring alleles of HvEIF4E exclusively contained non-synonymous amino acid substitutions (including in-frame sequence deletions and insertions), loss-of-function alleles were predominantly responsible for the HvPDIL5-1 conferred bymovirus resistance. A strong correlation between the geographic origin and the frequency of Barley accessions carrying resistance-conferring alleles was evident for each of the two host factor genes, indicating adaptive selection for bymovirus resistance in cultivated Barley from East Asia.

  • transferability and polymorphism of Barley est ssr markers used for phylogenetic analysis in hordeum chilense
    BMC Plant Biology, 2008
    Co-Authors: Almudena Castillo, Andreas Graner, Hikmet Budak, Rajeev K Varshney, Gabriel Dorado, Pilar Hernandez
    Abstract:

    Background: Hordeum chilense, a native South American diploid wild Barley, is a potential source of useful genes for cereal breeding. The use of this wild species to increase genetic variation in cereals will be greatly facilitated by marker-assisted selection. Different economically feasible approaches have been undertaken for this wild species with limited direct agricultural use in a search for suitable and cost-effective markers. The availability of Expressed Sequence Tags (EST) derived microsatellites or simple sequence repeat (SSR) markers, commonly called as EST-SSRs, for Barley (Hordeum vulgare) represents a promising source to increase the number of genetic markers available for the H. chilense genome. Results: All of the 82 Barley EST-derived SSR primer pairs tested for transferability to H. chilense amplified products of correct size from this species. Of these 82 Barley EST-SSRs, 21 (26%) showed polymorphism among H. chilense lines. Identified polymorphic markers were used to test the transferability and polymorphism in other Poaceae family species with the aim of establishing H. chilense phylogenetic relationships. Triticum aestivum-H. chilense addition lines allowed us to determine the chromosomal localizations of EST-SSR markers and confirm conservation of the linkage group. Conclusion: From the present study a set of 21 polymorphic EST-SSR markers have been identified to be useful for diversity analysis of H. chilense, related wild Barleys like H. murinum, and for wheat marker-assisted introgression breeding. Across-genera transferability of the Barley ESTSSR markers has allowed phylogenetic inference within the Triticeae complex.

  • exploiting est databases for the development and characterization of gene derived ssr markers in Barley hordeum vulgare l
    Theoretical and Applied Genetics, 2003
    Co-Authors: Thomas Thiel, Rajeev K Varshney, Wolfgang Michalek, Andreas Graner
    Abstract:

    A software tool was developed for the identification of simple sequence repeats (SSRs) in a Barley (Hordeum vulgare L.) EST (expressed sequence tag) database comprising 24,595 sequences. In total, 1,856 SSR-containing sequences were identified. Trimeric SSR repeat motifs appeared to be the most abundant type. A subset of 311 primer pairs flanking SSR loci have been used for screening polymorphisms among six Barley cultivars, being parents of three mapping populations. As a result, 76 EST-derived SSR-markers were integrated into a Barley genetic consensus map. A correlation between polymorphism and the number of repeats was observed for SSRs built of dimeric up to tetrameric units. 3′-ESTs yielded a higher portion of polymorphic SSRs (64%) than 5′-ESTs did. The estimated PIC (polymorphic information content) value was 0.45 ± 0.03. Approximately 80% of the SSR-markers amplified DNA fragments in Hordeum bulbosum, followed by rye, wheat (both about 60%) and rice (40%). A subset of 38 EST-derived SSR-markers comprising 114 alleles were used to investigate genetic diversity among 54 Barley cultivars. In accordance with a previous, RFLP-based, study, spring and winter cultivars, as well as two- and six-rowed Barleys, formed separate clades upon PCoA analysis. The results show that: (1) with the software tool developed, EST databases can be efficiently exploited for the development of cDNA-SSRs, (2) EST-derived SSRs are significantly less polymorphic than those derived from genomic regions, (3) a considerable portion of the developed SSRs can be transferred to related species, and (4) compared to RFLP-markers, cDNA-SSRs yield similar patterns of genetic diversity.

Nils Stein - One of the best experts on this subject based on the ideXlab platform.

  • sequence diversification in recessive alleles of two host factor genes suggests adaptive selection for bymovirus resistance in cultivated Barley from east asia
    Theoretical and Applied Genetics, 2017
    Co-Authors: Ping Yang, Bernhard J. Hofinger, Kostya Kanyuka, Frank Ordon, Andreas Graner, Benjamin Kilian, Antje Habekus, Nils Stein
    Abstract:

    Two distinct patterns of sequence diversity for the recessive alleles of two host factors HvPDIL5 - 1 and HvEIF4E indicated the adaptive selection for bymovirus resistance in cultivated Barley from East Asia. Plant pathogens are constantly challenging plant fitness and driving resistance gene evolution in host species. Little is known about the evolution of sequence diversity in host recessive resistance genes that interact with plant viruses. Here, by combining previously published and newly generated targeted re-sequencing information, we systematically analyzed natural variation in a broad collection of wild (Hordeum spontaneum; Hs) and domesticated Barleys (Hordeum vulgare; Hv) using the full-length coding sequence of the two host factor genes, HvPDIL5-1 and HvEIF4E, conferring recessive resistance to the agriculturally important Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV). Interestingly, two types of gene evolution conferred by sequence variation in domesticated Barley, but not in wild Barley were observed. Whereas resistance-conferring alleles of HvEIF4E exclusively contained non-synonymous amino acid substitutions (including in-frame sequence deletions and insertions), loss-of-function alleles were predominantly responsible for the HvPDIL5-1 conferred bymovirus resistance. A strong correlation between the geographic origin and the frequency of Barley accessions carrying resistance-conferring alleles was evident for each of the two host factor genes, indicating adaptive selection for bymovirus resistance in cultivated Barley from East Asia.

  • Natural variation in a homolog of Antirrhinum CENTRORADIALIS contributed to spring growth habit and environmental adaptation in cultivated Barley
    Nature Genetics, 2012
    Co-Authors: Jordi Comadran, Benjamin Kilian, Joanne Russell, Luke Ramsay, Nils Stein, Martin W Ganal, Paul D Shaw, Micha Bayer, W T B Thomas, David Marshall
    Abstract:

    Robbie Waugh and colleagues report that the EARLINESS PER SE (EPS2) locus is associated with spring growth habit and environmental adaptation in Barley. Resequencing the Barley homolog of CENTRORADIALIS, located within the EPS2 locus, in 216 spring and 207 winter Barley accessions identified haplotypes at HvCEN that correspond with winter or spring growth habit. As early farming spread from the Fertile Crescent in the Near East around 10,000 years before the present1, domesticated crops encountered considerable ecological and environmental change. Spring-sown crops that flowered without the need for an extended period of cold to promote flowering and day length–insensitive crops able to exploit the longer, cooler days of higher latitudes emerged and became established. To investigate the genetic consequences of adaptation to these new environments, we identified signatures of divergent selection in the highly differentiated modern-day spring and winter Barleys. In one genetically divergent region, we identify a natural variant of the Barley homolog of Antirrhinum CENTRORADIALIS2 (HvCEN) as a contributor to successful environmental adaptation. The distribution of HvCEN alleles in a large collection of wild and landrace accessions indicates that this involved selection and enrichment of preexisting genetic variants rather than the acquisition of mutations after domestication.

  • Barley grain maturation and germination metabolic pathway and regulatory network commonalities and differences highlighted by new mapman pageman profiling tools
    Plant Physiology, 2008
    Co-Authors: Nese Sreenivasulu, Nils Stein, Bjorn Usadel, Andreas Winter, Volodymyr Radchuk, Uwe Scholz, Winfriede Weschke, Marc Strickert, Timothy J Close, Mark Stitt
    Abstract:

    Plant seeds prepare for germination already during seed maturation. We performed a detailed transcriptome analysis of Barley (Hordeum vulgare) grain maturation, desiccation, and germination in two tissue fractions (starchy endosperm/aleurone and embryo/scutellum) using the Affymetrix Barley1 GeneChip. To aid data evaluation, Arabidopsis thaliana MapMan and PageMan tools were adapted to Barley. The analyses allow a number of conclusions: (1) Cluster analysis revealed a smooth transition in transcription programs between late seed maturation and germination within embryo tissues, but not in the endosperm/aleurone. (2) More than 12,000 transcripts are stored in the embryo of dry Barley grains, many of which are presumably activated during germination. (3) Transcriptional activation of storage reserve mobilization events occurs at an early stage of germination, well before radicle protrusion. (4) Key genes of gibberellin (GA) biosynthesis are already active during grain maturation at a time when abscisic acid peaks suggesting the formation of an endogenous store of GA in the aleurone. This GA probably acts later during germination in addition to newly synthesized GA. (5) Beside the well-known role of GA in gene activation during germination spatiotemporal expression data and cis-element searches in homologous rice promoters confirm an equally important gene-activating role of abscisic acid during this developmental period. The respective regulatory webs are linked to auxin and ethylene controlled networks. In summary, new bioinformatics PageMan and MapMan tools developed in Barley have been successfully used to investigate in detail the transcriptome relationships between seed maturation and germination in an important crop plant.

Robert H Symons - One of the best experts on this subject based on the ideXlab platform.

  • rapid and informative assays for yd2 the Barley yellow dwarf virus resistance gene based on the nucleotide sequence of a closely linked gene
    Molecular Breeding, 1998
    Co-Authors: Christopher M Ford, N G Paltridge, John P Rathjen, Robert L Moritz, Richard J Simpson, Robert H Symons
    Abstract:

    This paper describes the isolation of the cDNA encoding a protein previously shown to be indicative of the disease-resistance phenotype mediated by the Yd2 gene in Barley (Hordeum vulgare L.). Amino acid sequences of four peptides obtained after isolation of the protein on two-dimensional polyacrylamide gels were completely homologous to sequences occurring within subunit E of Barley vacuolar proton-translocating ATPase. Nucleotide sequence data of cloned cDNAs from both Yd2 and non-Yd2 Barley varieties showed an amino acid change arising from a single-base-pair polymorphism. This was predicted to result in the shift in isoelectric point used previously to differentiate the protein in Yd2 and non-Yd2 Barleys. Earlier work had indicated very close linkage between the gene from which this cDNA is derived, which we have named Ylp, and Yd2, the Barley yellow dwarf virus resistance gene. We report here the development of PCR-based assays which discriminate between the two alleles of Ylp and thereby act as valuable predictors of Yd2 for Barley breeders and others looking to study this important gene in cereal crops. The validity of each assay was tested with an extensive survey of over 100 Barley varieties currently under cultivation in Australia or of importance to Australian Barley breeding programmes. Complete agreement was observed between the allele of Ylp detected by the assay and the known Yd2 status of the Barleys. A dominant PCR marker for the Yd2-associated allele of Ylp was subsequently developed using an allele-specific primer pair. This fast and economical assay will have broad application in the marker-assisted selection of Yd2-containing lines.

  • the yd2 gene for Barley yellow dwarf virus resistance maps close to the centromere on the long arm of Barley chromosome 3
    Theoretical and Applied Genetics, 1996
    Co-Authors: Nicholas C Collins, Christopher M Ford, N G Paltridge, Robert H Symons
    Abstract:

    Barley yellow dwarf luteovirus (BYDV) causes serious yield losses in all cereals worldwide. The Yd2 gene from a number of Ethiopian Barleys (Hordeum vulgare L.) has been the most effective means of providing resistance against BYDV in cultivated Barley. Isolation of the Yd2 gene will enable characterisation of the molecular basis of the Yd2-BYDV interaction. This paper describes the first stage in a project to isolate the gene: the construction of a detailed linkage map of the Yd2 region. The map encompasses 27.6 centiMorgans (cM) of chromosome 3 and contains 19 RFLPs, 2 morphological marker loci, the centromere and Yd2. In the mapping population of 106 F2 individuals, Yd2 perfectly cosegregated with the RFLP loci Xwg889 and XYlp, which were located on the long arm, 0.5 cM from the centromere. The two morphological marker loci, uzu dwarfand white stripe j, both mapped distal to Yd2. The protein product of the gene at the XYlp locus will provide a convenient assay for the selection of Yd2 during the breeding of BYDV-resistant Barley varieties.