Minimizing ergot infection in hybrid rye by a SMART breeding approach

In Hybridsorten bei Winterroggen führt das Restorergen Rfp1 zu einer vollständigen Restauration der männlichen Fertilität und trägt dazu bei, die Kontamination des Erntegutes mit Mutterkorn zu minimieren. Wir beschreiben Ergebnisse zur Validierung neuer Rfp1-Selektionsmarker an Elitezuchtmaterial des Roggens. Für alle per molekularer Markeranalyse genotypisierten Individuen wurde eine perfekte Übereinstimmung zwischen der postulierten genetischen Konstitution am Restorerlocus Rfp1 und dem Pollenschüttungsvermögen in den Testkreuzungsnachkommenschaften beobachtet. Rekombination zwischen den untersuchten Rfp1-Markern zeigt, dass die neuen Selektionsmarker dazu geeignet sind, rekombinativ verkleinerte, Rfp1-tragende Genomsegmente zu identifizieren. Es konnte gezeigt werden, dass die mit Rfp1 assoziierten, eng gekoppelten Markerallele diagnostisch für Rfp1 sind. Die vorgestellten Ergebnisse belegen, dass die neuen Selektionsmarker eine effiziente Genotypisierung aktueller Elitezuchtlinien im Hinblick auf das Rfp1-Restorergen ermöglichen. Für die mit Rfp1 assoziierten Selektionsmarker konnte in der vorliegenden Studie auch Kopplung mit dem Restorergen Rfc1 nachgewiesen werden. Diese Kopplungsbeziehungen lassen die validierten Marker daher für eine indirekte Selektion von Maintainer-Genotypen des C-Plasmas geeignet erscheinen. Die beobachtete Kopplung von STS-Markern zu Rfp1 bzw. Rfc1 bestätigt frühere Vermutungen, dass in dieser Region auf Chromosom 4RL entweder mehrere Restorergene lokalisiert sind oder es sich bei den betreffenden Restorergenen um Allele desselben Genortes handelt.The restorer gene Rfp1 results in an almost complete restoration of male fertility in hybrid rye varieties and, thus, contributes to minimize harvest contamination with ergot. Here, we report on the validation of recently established Rfp1 markers located on chromosome 4RL in elite breeding lines of rye. The Rfp1 genotypes, as deduced by molecular-marker analysis, perfectly corresponded with the degree of male fertility assessed in test crosses of individual genotpes with male sterile testers. Recombination could be observed between Rfp1 markers indicating their potential to reduce the donor chromosome segment carrying Rfp1. These marker alleles proved to be diagnostic for Rfp1 in current breeding lines. Taken together, results presented qualify the novel markers as efficent molecular tools to assess the restorer gene Rfp1 in elite breeding lines of rye. In addition, we have observed linkage of the Rfp1 markers to the restorer gene Rfc1. Thus, the validated markers should be applicable for marker-assisted selection strategies of maintainer genotypes of the male sterility inducing C cytoplasm, which occur at low frequency in European rye populations as well. The observed linkage of the STS markers to both Rfp1 and Rfc1 supports the assumption that the restorer genes identified on chromosome 4RL are either alleles of a single restorer gene or represent different linked genes located in this sub-genomic region

Two New Loci for Body-Weight Regulation Identified in a Joint Analysis of Genome-Wide Association Studies for Early-Onset Extreme Obesity in French and German Study Groups

Meta-analyses of population-based genome-wide association studies (GWAS) in adults have recently led to the detection of new genetic loci for obesity. Here we aimed to discover additional obesity loci in extremely obese children and adolescents. We also investigated if these results generalize by estimating the effects of these obesity loci in adults and in population-based samples including both children and adults. We jointly analysed two GWAS of 2,258 individuals and followed-up the best, according to lowest p-values, 44 single nucleotide polymorphisms (SNP) from 21 genomic regions in 3,141 individuals. After this DISCOVERY step, we explored if the findings derived from the extremely obese children and adolescents (10 SNPs from 5 genomic regions) generalized to (i) the population level and (ii) to adults by genotyping another 31,182 individuals (GENERALIZATION step). Apart from previously identified FTO, MC4R, and TMEM18, we detected two new loci for obesity: one in SDCCAG8 (serologically defined colon cancer antigen 8 gene; p = 1.85610 x 10(-8) in the DISCOVERY step) and one between TNKS (tankyrase, TRF1-interacting ankyrin-related ADP-ribose polymerase gene) and MSRA (methionine sulfoxide reductase A gene; p = 4.84 x 10(-7)), the latter finding being limited to children and adolescents as demonstrated in the GENERALIZATION step. The odds ratios for early-onset obesity were estimated at similar to 1.10 per risk allele for both loci. Interestingly, the TNKS/MSRA locus has recently been found to be associated with adult waist circumference. In summary, we have completed a meta-analysis of two GWAS which both focus on extremely obese children and adolescents and replicated our findings in a large followed-up data set. We observed that genetic variants in or near FTO, MC4R, TMEM18, SDCCAG8, and TNKS/MSRA were robustly associated with early-onset obesity. We conclude that the currently known major common variants related to obesity overlap to a substantial degree between children and adults

Rapid sample delivery for megahertz serial crystallography at X-ray FELs

Liquid microjets are a common means of delivering protein crystals to the focus of X-ray free-electron lasers (FELs) for serial femtosecond crystallography measurements. The high X-ray intensity in the focus initiates an explosion of the microjet and sample. With the advent of X-ray FELs with megahertz rates, the typical velocities of these jets must be increased significantly in order to replenish the damaged material in time for the subsequent measurement with the next X-ray pulse. This work reports the results of a megahertz serial diffraction experiment at the FLASH FEL facility using 4.3 nm radiation. The operation of gas-dynamic nozzles that produce liquid microjets with velocities greater than 80 m s-1 was demonstrated. Furthermore, this article provides optical images of X-ray-induced explosions together with Bragg diffraction from protein microcrystals exposed to trains of X-ray pulses repeating at rates of up to 4.5 MHz. The results indicate the feasibility for megahertz serial crystallography measurements with hard X-rays and give guidance for the design of such experiments

Segmented flow generator for serial crystallography at the European X-ray free electron laser

Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported

Improving Yield and Yield Stability in Winter Rye by Hybrid Breeding

Rye is the only cross-pollinating small-grain cereal. The unique reproduction biology results in an exceptional complexity concerning genetic improvement of rye by breeding. Rye is a close relative of wheat and has a strong adaptation potential that refers to its mating system, making this overlooked cereal readily adjustable to a changing environment. Rye breeding addresses the emerging challenges of food security associated with climate change. The systematic identification, management, and use of its valuable natural diversity became a feasible option in outbreeding rye only following the establishment of hybrid breeding late in the 20th century. In this article, we review the most recent technological advances to improve yield and yield stability in winter rye. Based on recently released reference genome sequences, SMART breeding approaches are described to counterbalance undesired linkage drag effects of major restorer genes on grain yield. We present the development of gibberellin-sensitive semidwarf hybrids as a novel plant breeding innovation based on an approach that is different from current methods of increasing productivity in rye and wheat. Breeding of new rye cultivars with improved performance and resilience is indispensable for a renaissance of this healthy minor cereal as a homogeneous commodity with cultural relevance in Europe that allows for comparatively smooth but substantial complementation of wheat with rye-based diets, supporting the necessary restoration of the balance between human action and nature