Genome-wide association mapping for seedling and adult resistance to powdery mildew in barley

KEY MESSAGE

Two new major QTL were identified for powdery mildew resistance. We confirmed that the QTL on 7HS contributed mainly to the adult-plant resistance, while another one on chromosome arm 1HS made a significant contribution to the seedling resistance. Powdery mildew (PM), caused by Blumeria hordei, can occur at all post emergent stages of barley and constantly threatens crop production. To identify more genes for effective resistance to powdery mildew for use in breeding programs, 696 barley accessions collected from different regions of the world were evaluated for PM resistance at seedling and adult growth stages in three different states of Australia. These barley accessions were genotyped using DArTSeq with over 18,000 markers for a genome-wide association study (GWAS). Using the FarmCPU model, 54 markers showed significant associations with PM resistance scored at the seedling and adult-plant stages in different states of Australia. Another 40 markers showed tentative associations (LOD > 4.0) with resistance. These markers are distributed across all seven barley chromosomes. Most of them were grouped into eleven QTL regions, coinciding with the locations of most of the reported resistance genes. Two major MTAs were identified on chromosome arms 3HS and 5HL, with one on 3HS contributing to adult plant resistance and the one on 5HL to both seedling and adult plant resistance. An MTA on 7HS contributed mainly to the adult-plant resistance, while another one on chromosome arm 1HS made a significant contribution to the seedling resistance.

Mining the Vavilov wheat diversity panel for new sources of adult plant resistance to stripe rust

Multi-year evaluation of the Vavilov wheat diversity panel identified new sources of adult plant resistance to stripe rust. Genome-wide association studies revealed the key genomic regions influencing resistance, including seven novel loci. Wheat stripe rust (YR) caused by Puccinia striiformis f. sp. tritici (Pst) poses a significant threat to global food security. Resistance genes commonly found in many wheat varieties have been rendered ineffective due to the rapid evolution of the pathogen. To identify novel sources of adult plant resistance (APR), 292 accessions from the N.I. Vavilov Institute of Plant Genetic Resources, Saint Petersburg, Russia, were screened for known APR genes (i.e. Yr18, Yr29, Yr46, Yr33, Yr39 and Yr59) using linked polymerase chain reaction (PCR) molecular markers. Accessions were evaluated against Pst (pathotype 134 E16 A + Yr17 + Yr27) at seedling and adult plant stages across multiple years (2014, 2015 and 2016) in Australia. Phenotypic analyses identified 132 lines that potentially carry novel sources of APR to YR. Genome-wide association studies (GWAS) identified 68 significant marker-trait associations (P < 0.001) for YR resistance, representing 47 independent quantitative trait loci (QTL) regions. Fourteen genomic regions overlapped with previously reported Yr genes, including Yr29, Yr56, Yr5, Yr43, Yr57, Yr30, Yr46, Yr47, Yr35, Yr36, Yrxy1, Yr59, Yr52 and YrYL. In total, seven QTL (positioned on chromosomes 1D, 2A, 3A, 3D, 5D, 7B and 7D) did not collocate with previously reported genes or QTL, indicating the presence of promising novel resistance factors. Overall, the Vavilov diversity panel provides a rich source of new alleles which could be used to broaden the genetic bases of YR resistance in modern wheat varieties.

Genetic characterization of adult-plant resistance to tan spot (syn, yellow spot) in wheat

QTL mapping identified key genomic regions associated with adult-plant resistance to tan spot, which are effective even in the presence of the sensitivity gene Tsn1, thus serving as a new genetic solution to develop disease-resistant wheat cultivars. Improving resistance to tan spot (Pyrenophora tritici-repentis; Ptr) in wheat by eliminating race-specific susceptibility genes is a common breeding approach worldwide. The potential to exploit variation in quantitative forms of resistance, such as adult-plant resistance (APR), offers an alternative approach that could lead to broad-spectrum protection. We previously identified wheat landraces in the Vavilov diversity panel that exhibited high levels of APR despite carrying the sensitivity gene Tsn1. In this study, we characterised the genetic control of APR by developing a recombinant inbred line population fixed for Tsn1, but segregating for the APR trait. Linkage mapping using DArTseq markers and disease response phenotypes identified a QTL associated with APR to Ptr race 1 (producing Ptr ToxA- and Ptr ToxC) on chromosome 2B (Qts.313-2B), which was consistently detected in multiple adult-plant experiments. Additional loci were also detected on chromosomes 2A, 3D, 5A, 5D, 6A, 6B and 7A at the seedling stage, and on chromosomes 1A and 5B at the adult stage. We demonstrate that Qts.313-2B can be combined with other adult-plant QTL (i.e. Qts.313-1A and Qts.313-5B) to strengthen resistance levels. The APR QTL reported in this study provide a new genetic solution to tan spot in Australia and could be deployed in wheat cultivars, even in the presence of Tsn1, to decrease production losses and reduce the application of fungicides.

[Treatment mapping of lower urinary tract symptoms due to benign prostatic hyperplasia-an analysis of the Governing Body of German Prostate Centers]

BACKGROUND

Due to the high incidence and demographic development, there is an urgent need for healthcare research data on lower urinary tract symptoms due to benign prostatic hyperplasia (LTUS/BPH). Since 2005 the Governing Body of German Prostate Centers (DVPZ) has been collecting data from 22 prostate centers in order to determine the quality and type of cross-sectoral care in particular for LUTS/BPH patients.

OBJECTIVES

Presentation of the DVPZ database in general, as well as an investigation of treatment patterns for medical and instrumental therapies.

MATERIALS AND METHODS

The analysis is based on UroCloud data sets from 30 November 2017. In the UroCloud data on diagnostics, therapy and course of disease are recorded in a web-based manner.

RESULTS

A total of 29,555 therapies were documented for 18,299 patients (1.6/patient), divided into 48.5% instrumental, 29.2% medical treatment, and 18.0% "wait and see" (in 4.3% no assignment was possible). Patients treated with an instrumental therapy were oldest (median: 72 years, interquartile range: 66-77), had the largest prostate volumes (50 ml, 35-75 ml), and were mostly bothered by symptoms (International Prostate Symptom Score = 19/4). The majority of patients under medical treatment received alphablockers (56%); phytotherapeutics were used least frequently (3%). Instrumental therapies are dominated by transurethral resection (TUR) of the prostate (60.0%), open prostatectomy (9.4%) and laser therapy (5.0%), with laser therapy having the shortest hospital stay (5 days) and the lowest transfusion and re-intervention rates (1.0% and 4.6%, respectively).

CONCLUSIONS

The DVPZ certificate covers the complete spectrum of cross-sectoral care for LUTS/BPH patients and documents the use of the various therapies as well as their application and effectiveness in the daily routine setting.

Discovering new alleles for yellow spot resistance in the Vavilov wheat collection

GWAS detected 11 yellow spot resistance QTL in the Vavilov wheat collection. Promising adult-plant resistance loci could provide a sustainable genetic solution to yellow spot in modern wheat varieties. Yellow spot, caused by the fungal pathogen Pyrenophora tritici-repentis (Ptr), is the most economically damaging foliar disease of wheat in Australia. Genetic resistance is considered to be the most sustainable means for disease management, yet the genomic regions underpinning resistance to Ptr, particularly adult-plant resistance (APR), remain vastly unknown. In this study, we report results of a genome-wide association study using 295 accessions from the Vavilov wheat collection which were extensively tested for response to Ptr infections in glasshouse and field trials at both seedling an adult growth stages. Combining phenotypic datasets from multiple experiments in Australia and Russia with 25,286 genome-wide, high-quality DArTseq markers, we detected a total of 11 QTL, of which 5 were associated with seedling resistance, 3 with all-stage resistance, and 3 with APR. Interestingly, the novel APR QTL were effective even in the presence of host sensitivity gene Tsn1. These genomic regions could offer broad-spectrum yellow spot protection, not just to ToxA but also other pathogenicity or virulence factors. Vavilov wheat accessions carrying APR QTL combinations displayed enhanced levels of resistance highlighting the potential for QTL stacking through breeding. We propose that the APR genetic factors discovered in our study could be used to improve resistance levels in modern wheat varieties and contribute to the sustainable control of yellow spot.

Disease resistance genes in a doubled haploid population of two-rowed barley segregating for malting quality attributes

Malting barley (Hordeum vulgare L.) improvement involves selection for many quality traits, but the search for and deployment of resistance genes has continued to be an equally important endeavour. As an aid to phenotypic selection in breeding programs, gene mapping can serve to characterise genes known to exist in elite breeding lines. In the present study, 180 doubled haploid lines derived from the cross of VB9524/ND11231*12 were screened for disease resistance under field and greenhouse conditions. Quantitative trait locus (QTL) mapping and classical genetic linkage approaches were used to identify and map QTLs for resistance to powdery mildew (Blumeria graminis f.sp. hordei), net form of net blotch (Pyrenophora teres f. teres) and stem rust (Puccinia graminis f.sp. tritici). The analyses offered a comparison between QTL mapping and traditional genetic linkage analysis. Both approaches identified a QTL for powdery mildew resistance on chromosome 1H, which mapped to the approximate genomic location of the Mla6 gene. Similarly, both methods identified a major QTL for resistance to net form of net blotch on chromosome 6H and for stem rust resistance on chromosome 7H. The QTL for stem rust resistance on 7H mapped to the approximate location of the Rpg1 gene. Classical linkage analysis identified the 3 QTLs with major effects, but was unable to detect 3 other loci with minor effects.

Crystal structures and thermotropic properties of alkyl alpha-D-glucopyranosides and their hydrates

Thermotropic properties and crystal structures of alkyl alpha-D-glucopyranosides and their hydrates were estimated by X-ray, DSC and thermogravimetric measurements (TGA). Monohydrates rapidly lose their crystal water several degrees below the melting point of the anhydrous glucopyranosides. The melting points of the monohydrates measured in DSC pressure cells (chain length longer than seven) are lower, and the clearing points higher than those of the anhydrous glucosides. Layer distances of smectic and crystalline phases of anhydrous compounds were established. Melting points, densities and layer distances of the crystalline anhydrous glucopyranosides display strong even-odd effects. The strong decrease of these effects in the case of the monohydrates can be elucidated by the results of X-ray crystal structure analysis.

Lyotropic Liquid Crystalline Phases from Symmetric Double-Tailed Surfactants: Sodium 1'-(6)-Undecylbenzenesulfonate, 1'-(7)-Tridecylbenzenesulfonate, and 1'-(8)- Pentadecylbenzenesulfonate in Water

Phase diagrams of binary symmetric double-tailed alkylbenzenesulfonate surfactant/water systems, as well as the structure of the phases, were determined using crossed polars, polarized light microscopy, 2H NMR spectroscopy, Nomarski differential interference contrast optics, and cryo-transmission electron microscopy. The isotropic phase, the lamellar phase, and a high-viscosity solution representing an intermediate between the isotropic phase and the mesophase, which refers to the beginning of the formation of vesicles, were found. As may be expected, the isotropic phases at higher concentrations are formed mostly at higher temperatures. Isotropic regions are followed by regions characterized as the isotropic solutions containing vesicles; the optically isotropic phase contains a lamellar dispersion of vesicles in solution. The viscosity of these phases is found to be high near the borderline of the two-phase regions. At the same concentrations two-phase regions were found to contain the isotropic + lamellar phases at the higher temperature and the isotropic + crystalline phase at the lower temperature. Molecular-mechanical and semiempirical quantum-mechanical calculation searches for the global minimum in the conformational space of alkylbenzenesulfonate ions were conducted to examine the influence of monomer molecular structure on the micellar shape. Copyright 1998 Academic Press.