Mapowanie genów i QTL związanych z reakcją na stres niedoboru wody z wykorzystaniem wysokorozdzielczej mapy genetycznej Hordeum vulgare L.

Drought is one of the most adverse abiotic stresses limiting plant growth and development, as well as the major factor influencing yield loss. Among cereals, barley (Hordeum vulgare L.) is ranked fourth in terms of harvested acreage and as a staple food is attracting renewed attention, because of its wide adaptation to the harsh environments. Plants have evolved various mechanisms to cope with water deficit at different biological levels. However, there is an enormous challenge to decipher molecular mechanisms influencing particular complex phenotypic traits under water-limiting conditions due to polygenic inheritance controlled by several genes of small effects. The presented research shows a comprehensive approach for elucidation of molecular basis of drought tolerance in barley. The study includes construction of high-density SNP and SSR-based genetic map with positioned functional candidate genes (CGs), mapping of QTLs for physiological and biochemical traits associated with drought tolerance, projection of QTL confidence intervals on physical barley genome map, and the retrievement of positional CGs, followed by Gene Ontology (GO) enrichment analysis. The genetic consensus map was constructed using three RIL populations, developed from the crosses between European cultivars and Syrian breeding lines, and was enriched with 64 genes, encoding barley orthologues of functional and regulatory drought tolerance-related genes described in model species, as well as the genes derived from the transcriptome analysis of parental genotypes of the study, performed under water deficit conditions. The genetic map spans 941.86 cM with resolution of 1.1 cM and contains 875 loci clustered into 13 linkage groups, as a result of presence of the genomic regions with markers exhibited significant segregation distortion, clearly separated from neighboring chromosome segments. A total of sixty-six QTLs for 26 physiological and biochemical traits that describe water relations, photosynthetic efficiency, content of osmoprotectants and hormones, and activity of antioxidants, were identified. For the first time, QTLs for ethylene, glucose, sucrose, maltose, raphinose, α-tocopferol, γ-tocotrienol content, catalase activity, and various photosynthetic parameters have been mapped in barley. All of the 33 detected QTLs for 18 physiological and biochemical parameters under drought conditions and stress indices (SI) were a major QTLs with the value of phenotypic variance exceeding 10%. The mapped QTLs tended to be clustered in particular chromosome regions. Based on overlapping confidence intervals of QTLs, 11 hotspots were identified that enclosed 61% of mapped QTLs. Four of them were localized in chromosome 2H. The existence of hotspots suggests a common genetic background of analyzed physiological and biochemical traits mapped in these regions or presence of closely linked genes that control them. The genetic and physical map integration was based on the position of markers defining boundaries of QTL confidence intervals in barley genome and allowed the identification of 1101 positional CGs within the chromosomal regions of drought-specific QTLs. The GO enrichment resulted in the designation of 143 CGs potentially involved in Biological Processes (BP) significantly over-represented in the gen sets associated with water relations, photosynthetic efficiency, content of osmoprotectants and hormones, and activity of antioxidants, compared with the genome-wide background frequency. Among them were genes encoding antioxidants, carboxylic acid biosynthesis enzymes, heat shock proteins, small auxin upregulated RNAs, nitric-oxide synthase, ATP sulfurylases, and proteins involved in the metabolism of molybdenum cofactor synthesis substrates as well as regulation of flowering time

Drought-related secondary metabolites of barley (Hordeum vulgare L.) leaves and their metabolomic quantitative trait loci

Determining the role of plant secondary metabolites in stress conditions is problematic due to the diversity of their structures and the complexity of their interdependence with different biological pathways. Correlation of metabolomic data with the genetic background provides essential information about the features of metabolites. LC-MS analysis of leaf metabolites from 100 barley recombinant inbred lines (RILs) revealed that 98 traits among 135 detected phenolic and terpenoid compounds significantly changed their level as a result of drought stress. Metabolites with similar patterns of change were grouped in modules, revealing differences among RILs and parental varieties at early and late stages of drought. The most significant changes in stress were observed for ferulic and sinapic acid derivatives as well as acylated glycosides of flavones. The tendency to accumulate methylated compounds was a major phenomenon in this set of samples. In addition, the polyamine derivatives hordatines as well as terpenoid blumenol C derivatives were observed to be drought related. The correlation of drought-related compounds with molecular marker polymorphisms resulted in the definition of metabolomic quantitative trait loci in the genomic regions of single-nucleotide polymorphism 3101-111 and simple sequence repeat Bmag0692 with multiple linkages to metabolites. The associations pointed to genes related to the defence response and response to cold, heat and oxidative stress, but not to genes related to biosynthesis of the compounds. We postulate that the significant metabolites have a role as antioxidants, regulators of gene expression and modulators of protein function in barley during drought

QTLs for earliness and yield-forming traits in the Lubuski x CamB barley RIL population under various water regimes

This work was supported by the European Regional Development Fund through the Innovative Economy Programme 2007?2013, project WND-POIG.01.03.01?00?101/08 POLAPGEN-BD "Biotechnological tools for breeding cereals with increased resistance to drought".Drought has become more frequent in Central Europe causing large losses in cereal yields, especially of spring crops. The development of new varieties with increased tolerance to drought is a key tool for improvement of agricultural productivity. Material for the study consisted of 100 barley recombinant inbred lines (RILs) (LCam) derived from the cross between Syrian and European parents. The RILs and parental genotypes were examined in greenhouse experiments under well-watered and water-deficit conditions. During vegetation the date of heading, yield and yield-related traits were measured. RIL population was genotyped with microsatellite and single nucleotide polymorphism markers. This population, together with two other populations, was the basis for the consensus map construction, which was used for identification of quantitative trait loci (QTLs) affecting the traits. The studied lines showed a large variability in heading date. It was noted that drought-treatment negatively affected the yield and its components, especially when applied at the flag leaf stage. In total, 60 QTLs were detected on all the barley chromosomes. The largest number of QTLs was found on chromosome 2H. The main QTL associated with heading, located on chromosome 2H (Q.HD.LC-2H), was identified at SNP marker 5880–2547, in the vicinity of Ppd-H1 gene. SNP 5880–2547 was also the closest marker to QTLs associated with plant architecture, spike morphology and grain yield. The present study showed that the earliness allele from the Syrian parent, as introduced into the genome of an European variety could result in an improvement of barley yield performance under drought conditions.European Regional Development Fun

Quantitative trait loci for plant height in Maresi × CamB barley population and their associations with yield-related traits under different water regimes

High-yielding capacity of the modern barley varieties is mostly dependent on the sources of semi-dwarfness associated with the sdw1/denso locus. The objective of the study was to identify quantitative trait loci (QTLs) associated with the plant height and yield potential of barley recombinant inbred lines (RILs) grown under various soil moisture regimes. The plant material was developed from a hybrid between the Maresi (European cv.) and CamB (Syrian cv.). A total of 103 QTLs affecting analysed traits were detected and 36 of them showed stable effects over environments. In total, ten QTLs were found to be significant only under water shortage conditions. Nine QTLs affecting the length of main stem were detected on 2H-6H chromosomes. In four of the detected QTLs, alleles contributed by Maresi had negative effects on that trait, the most significant being the QLSt-3H.1-1 in the 3H.1 linkage group. The close linkage between QTLs identified around the sdw1/denso locus, with positive alleles contributed by Maresi, indicates that the semi-dwarf cv. Maresi could serve as a donor of favourable traits resulting in grain yield improvement, also under water scarcity. Molecular analyses revealed that the Syrian cv. also contributed alleles which increased the yield potential. Available barley resources of genomic annotations were employed to the biological interpretation of detected QTLs. This approach revealed 26 over-represented Gene Ontology terms. In the projected support intervals of QGWSl-5H.3-2 and QLSt-5H.3 on the chromosome 5H, four genes annotated to ‘response to stress’ were found. It suggests that these QTL-regions may be involved in a response of plant to a wide range of environmental disturbances

Quantitative Trait Loci for Yield and Yield-Related Traits in Spring Barley Populations Derived from Crosses between European and Syrian Cultivars

<div><p>In response to climatic changes, breeding programmes should be aimed at creating new cultivars with improved resistance to water scarcity. The objective of this study was to examine the yield potential of barley recombinant inbred lines (RILs) derived from three cross-combinations of European and Syrian spring cultivars, and to identify quantitative trait loci (QTLs) for yield-related traits in these populations. RILs were evaluated in field experiments over a period of three years (2011 to 2013) and genotyped with simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers; a genetic map for each population was constructed and then one consensus map was developed. Biological interpretation of identified QTLs was achieved by reference to Ensembl Plants barley gene space. Twelve regions in the genomes of studied RILs were distinguished after QTL analysis. Most of the QTLs were identified on the 2H chromosome, which was the hotspot region in all three populations. Syrian parental cultivars contributed alleles decreasing traits' values at majority of QTLs for grain weight, grain number, spike length and time to heading, and numerous alleles increasing stem length. The phenomic and molecular approaches distinguished the lines with an acceptable grain yield potential combining desirable features or alleles from their parents, that is, early heading from the Syrian breeding line (Cam/B1/CI08887//CI05761) and short plant stature from the European semidwarf cultivar (Maresi).</p></div

Characteristics of the three individual linkage maps and the consensus barley map.

<p>Characteristics of the three individual linkage maps and the consensus barley map.</p

ANOVA results, variance components, and broad sense heritability estimates for phenotypic traits observed in RIL populations.

<p>ANOVA results, variance components, and broad sense heritability estimates for phenotypic traits observed in RIL populations.</p

Principal component biplots constructed for phenotypic traits observed in MCam, LCam and GH populations in years 2011 (red), 2012 (blue), and 2013 (green).

<p>Principal component biplots constructed for phenotypic traits observed in MCam, LCam and GH populations in years 2011 (red), 2012 (blue), and 2013 (green).</p

Profiles of cumulative water shortage (evapotranspiration—precipitation) at Cerekwica during period IV–VII in years 2011–2013: 2011- red; 2012—yellow; and 2013—blue; brown dot–germination.

<p>Profiles of cumulative water shortage (evapotranspiration—precipitation) at Cerekwica during period IV–VII in years 2011–2013: 2011- red; 2012—yellow; and 2013—blue; brown dot–germination.</p

QTLs identified in RIL populations MCam, LCam, and GH for observed phenotypic traits.

<p>QTL strength measured by the statistic −Log₁₀(<i>P</i>-value) with <i>P</i>-values for Wald test computed based on accumulated analysis of variance.</p