From genes to policy: mission-oriented governance of plant-breeding research and technologies

Mission-oriented governance of research focuses on inspirational, yet attainable goals and targets the sustainable development goals through innovation pathways. We disentangle its implications for plant breeding research and thus impacting the sustainability transformation of agricultural systems, as it requires improved crop varieties and management practices. Speedy success in plant breeding is vital to lower the use of chemical fertilizers and pesticides, increase crop resilience to climate stresses and reduce postharvest losses. A key question is how this success may come about? So far plant breeding research has ignored wider social systems feedbacks, but governance also failed to deliver a set of systemic breeding goals providing directionality and organization to research policy of the same. To address these challenges, we propose a heuristic illustrating the core elements needed for governing plant breeding research: Genetics, Environment, Management and Social system (GxExMxS) are the core elements for defining directions for future breeding. We illustrate this based on historic cases in context of current developments in plant phenotyping technologies and derive implications for governing research infrastructures and breeding programs. As part of mission-oriented governance we deem long-term investments into human resources and experimental set-ups for agricultural systems necessary to ensure a symbiotic relationship for private and public breeding actors and recommend fostering collaboration between social and natural sciences for working towards transdisciplinary collaboration.

Genetic Basis of Resistance to Warrior (-) Yellow Rust Race at the Seedling Stage in Current Central and Northern European Winter Wheat Germplasm

To evaluate genetic variability and seedling plant response to a dominating Warrior (-) race of yellow rust in Northern and Central European germplasm, we used a population of 229 winter wheat cultivars and breeding lines for a genome-wide association study (GWAS). A wide variation in yellow rust disease severity (based on infection types 1-9) was observed in this panel. Four breeding lines, TS049 (from Austria), TS111, TS185, and TS229 (from Germany), and one cultivar, TS158 (KWS Talent), from Germany were found to be resistant to Warrior (-) FS 53/20 and Warrior (-) G 23/19. The GWAS identified five significant SNPs associated with yellow rust on chromosomes 1B, 2A, 5B, and 7A for Warrior (-) FS 53/20, while one SNP on chromosome 5B was associated with disease for Warrior (-) G 23/19. For Warrior (-) FS 53/20, we discovered a new QTL for yellow rust resistance associated with the marker Kukri_c5357_323 on chromosome 1B. The resistant alleles G and T at the marker loci Kukri_c5357_323 on chromosome 1B and Excalibur_c17489_804 on chromosome 5B showed the largest effects (1.21 and 0.81, respectively) on the severity of Warrior (-) FS 53/20 and Warrior (-) G 23/19. Our results provide the basis for knowledge-based resistance breeding in the face of the enormous impact of the Warrior (-) race on wheat production in Europe.

Alternative scoring methods of fusarium head blight resistance for genomic assisted breeding

Fusarium head blight (FHB) is a fungal disease of wheat (Triticum aestivum.L) that causes yield losses and produces mycotoxins which could easily exceed the limits of the EU regulations. Resistance to FHB has a complex genetic architecture and accurate evaluation in breeding programs is key to selecting resistant varieties. The Area Under the Disease Progress Curve (AUDPC) is one of the commonly metric used as a standard methodology to score FHB. Although efficient, AUDPC requires significant costs in phenotyping to cover the entire disease development pattern. Here, we show that there are more efficient alternatives to AUDPC (angle, growing degree days to reach 50% FHB severity, and FHB maximum variance) that reduce the number of field assessments required and allow for fair comparisons between unbalanced evaluations across trials. Furthermore, we found that the evaluation method that captures the maximum variance in FHB severity across plots is the most optimal approach for scoring FHB. In addition, results obtained on experimental data were validated on a simulated experiment where the disease progress curve was modeled as a sigmoid curve with known parameters and assessment protocols were fully controlled. Results show that alternative metrics tested in this study captured key components of quantitative plant resistance. Moreover, the new metrics could be a starting point for more accurate methods for measuring FHB in the field. For example, the optimal interval for FHB evaluation could be predicted using prior knowledge from historical weather data and FHB scores from previous trials. Finally, the evaluation methods presented in this study can reduce the FHB phenotyping burden in plant breeding with minimal losses on signal detection, resulting in a response variable available to use in data-driven analysis such as genome-wide association studies or genomic selection.

Genome-wide association study and genomic prediction of resistance to stripe rust in current Central and Northern European winter wheat germplasm

We found two loci on chromosomes 2BS and 6AL that significantly contribute to stripe rust resistance in current European winter wheat germplasm. Stripe or yellow rust, caused by the fungus Puccinia striiformis Westend f. sp. tritici, is one of the most destructive wheat diseases. Sustainable management of wheat stripe rust can be achieved through the deployment of rust resistant cultivars. To detect effective resistance loci for use in breeding programs, an association mapping panel of 230 winter wheat cultivars and breeding lines from Northern and Central Europe was employed. Genotyping with the Illumina® iSelect® 25 K Infinium® single nucleotide polymorphism (SNP) genotyping array yielded 8812 polymorphic markers. Structure analysis revealed two subpopulations with 92 Austrian breeding lines and cultivars, which were separated from the other 138 genotypes from Germany, Norway, Sweden, Denmark, Poland, and Switzerland. Genome-wide association study for adult plant stripe rust resistance identified 12 SNP markers on six wheat chromosomes which showed consistent effects over several testing environments. Among these, two marker loci on chromosomes 2BS (RAC875_c1226_652) and 6AL (Tdurum_contig29607_413) were highly predictive in three independent validation populations of 1065, 1001, and 175 breeding lines. Lines with the resistant haplotype at both loci were nearly free of stipe rust symptoms. By using mixed linear models with those markers as fixed effects, we could increase predictive ability in the three populations by 0.13-0.46 compared to a standard genomic best linear unbiased prediction approach. The obtained results facilitate an efficient selection for stripe rust resistance against the current pathogen population in the Northern and Central European winter wheat gene pool.

Genetics of the Inverse Relationship between Grain Yield and Grain Protein Content in Common Wheat

Grain protein content (GPC) is one of the most important criteria to determine the quality of common wheat (Triticum aestivum). One of the major obstacles for bread wheat production is the negative correlation between GPC and grain yield (GY). Previous studies demonstrated that the deviation from this inverse relationship is highly heritable. However, little is known about the genetics controlling these deviations in common wheat. To fill this gap, we performed quantitative trait locus (QTL) analysis for GY, GPC, and four derived GY-GPC indices using an eight-way multiparent advanced generation intercross population comprising 394 lines. Interval mapping was conducted using phenotypic data from up to nine environments and genotypic data from a 20k single-nucleotide polymorphism array. The four indices were highly heritable (0.76–0.88) and showed distinct correlations to GY and GPC. Interval mapping revealed that GY, GPC, and GY-GPC indices were controlled by 6, 12, and 12 unique QTL, of which each explained only a small amount of phenotypic variance (R² ≤ 10%). Ten of the 12 index QTL were independent of loci affecting GY and GPC. QTL regions harboured several candidate genes, including Rht-1, WAPO-A1, TaTEF-7A, and NRT2.6-7A. The study confirmed the usefulness of indices to mitigate the inverse GY-GPC relationship in breeding, though the selection method should reflect their polygenic inheritance.

Quantitative Trait Loci Mapping of Adult Plant and Seedling Resistance to Stripe Rust (Puccinia striiformis Westend.) in a Multiparent Advanced Generation Intercross Wheat Population

Stripe rust caused by the biotrophic fungus Puccinia striiformis Westend. is one of the most important diseases of wheat worldwide, causing high yield and quality losses. Growing resistant cultivars is the most efficient way to control stripe rust, both economically and ecologically. Known resistance genes are already present in numerous cultivars worldwide. However, their effectiveness is limited to certain races within a rust population and the emergence of stripe rust races being virulent against common resistance genes forces the demand for new sources of resistance. Multiparent advanced generation intercross (MAGIC) populations have proven to be a powerful tool to carry out genetic studies on economically important traits. In this study, interval mapping was performed to map quantitative trait loci (QTL) for stripe rust resistance in the Bavarian MAGIC wheat population, comprising 394 F6 : 8 recombinant inbred lines (RILs). Phenotypic evaluation of the RILs was carried out for adult plant resistance in field trials at three locations across three years and for seedling resistance in a growth chamber. In total, 21 QTL for stripe rust resistance corresponding to 13 distinct chromosomal regions were detected, of which two may represent putatively new QTL located on wheat chromosomes 3D and 7D.

Peanut-induced anaphylaxis in children and adolescents: Data from the European Anaphylaxis Registry

BACKGROUND

Peanut allergy has a rising prevalence in high-income countries, affecting 0.5%-1.4% of children. This study aimed to better understand peanut anaphylaxis in comparison to anaphylaxis to other food triggers in European children and adolescents.

METHODS

Data was sourced from the European Anaphylaxis Registry via an online questionnaire, after in-depth review of food-induced anaphylaxis cases in a tertiary paediatric allergy centre.

RESULTS

3514 cases of food anaphylaxis were reported between July 2007 - March 2018, 56% in patients younger than 18 years. Peanut anaphylaxis was recorded in 459 children and adolescents (85% of all peanut anaphylaxis cases). Previous reactions (42% vs. 38%; p = .001), asthma comorbidity (47% vs. 35%; p < .001), relevant cofactors (29% vs. 22%; p = .004) and biphasic reactions (10% vs. 4%; p = .001) were more commonly reported in peanut anaphylaxis. Most cases were labelled as severe anaphylaxis (Ring&Messmer grade III 65% vs. 56% and grade IV 1.1% vs. 0.9%; p = .001). Self-administration of intramuscular adrenaline was low (17% vs. 15%), professional adrenaline administration was higher in non-peanut food anaphylaxis (34% vs. 26%; p = .003). Hospitalization was higher for peanut anaphylaxis (67% vs. 54%; p = .004).

CONCLUSIONS

The European Anaphylaxis Registry data confirmed peanut as one of the major causes of severe, potentially life-threatening allergic reactions in European children, with some characteristic features e.g., presence of asthma comorbidity and increased rate of biphasic reactions. Usage of intramuscular adrenaline as first-line treatment is low and needs to be improved. The Registry, designed as the largest database on anaphylaxis, allows continuous assessment of this condition.

Identification of eight QTL controlling multiple yield components in a German multi-parental wheat population, including Rht24, WAPO-A1, WAPO-B1 and genetic loci on chromosomes 5A and 6A

KEY MESSAGE

Quantitative trait locus (QTL) mapping of 15 yield component traits in a German multi-founder population identified eight QTL each controlling ≥2 phenotypes, including the genetic loci Rht24, WAPO-A1 and WAPO-B1. Grain yield in wheat (Triticum aestivum L.) is a polygenic trait representing the culmination of many developmental processes and their interactions with the environment. Toward maintaining genetic gains in yield potential, 'reductionist approaches' are commonly undertaken by which the genetic control of yield components, that collectively determine yield, are established. Here we use an eight-founder German multi-parental wheat population to investigate the genetic control and phenotypic trade-offs between 15 yield components. Increased grains per ear was significantly positively correlated with the number of fertile spikelets per ear and negatively correlated with the number of infertile spikelets. However, as increased grain number and fertile spikelet number per ear were significantly negatively correlated with thousand grain weight, sink strength limitations were evident. Genetic mapping identified 34 replicated quantitative trait loci (QTL) at two or more test environments, of which 24 resolved into eight loci each controlling two or more traits-termed here 'multi-trait QTL' (MT-QTL). These included MT-QTL associated with previously cloned genes controlling semi-dwarf plant stature, and with the genetic locus Reduced height 24 (Rht24) that further modulates plant height. Additionally, MT-QTL controlling spikelet number traits were located to chromosome 7A encompassing the gene WHEAT ORTHOLOG OF APO1 (WAPO-A1), and to its homoeologous location on chromosome 7B containing WAPO-B1. The genetic loci identified in this study, particularly those that potentially control multiple yield components, provide future opportunities for the targeted investigation of their underlying genes, gene networks and phenotypic trade-offs, in order to underpin further genetic gains in yield.

QTL mapping of adult plant and seedling resistance to leaf rust (Puccinia triticina Eriks.) in a multiparent advanced generation intercross (MAGIC) wheat population

The Bavarian MAGIC Wheat population, comprising 394 F6:8 recombinant inbred lines was phenotyped for Puccinia triticina resistance in multi-years' field trials at three locations and in a controlled environment seedling test. Simple intervall mapping revealed 19 QTL, corresponding to 11 distinct chromosomal regions. The biotrophic rust fungus Puccinia triticina is one of the most important wheat pathogens with the potential to cause yield losses up to 70%. Growing resistant cultivars is the most cost-effective and environmentally friendly way to encounter this problem. The emergence of leaf rust races being virulent against common resistance genes increases the demand for wheat varieties with novel resistances. In the past decade, the use of complex experimental populations, like multiparent advanced generation intercross (MAGIC) populations, has risen and offers great advantages for mapping resistances. The genetic diversity of multiple parents, which has been recombined over several generations, leads to a broad phenotypic diversity, suitable for high-resolution mapping of quantitative traits. In this study, interval mapping was performed to map quantitative trait loci (QTL) for leaf rust resistance in the Bavarian MAGIC Wheat population, comprising 394 F_6:8 recombinant inbred lines (RILs). Phenotypic evaluation of the RILs for adult plant resistance was carried out in field trials at three locations and two years, as well as in a controlled-environment seedling inoculation test. In total, interval mapping revealed 19 QTL, which corresponded to 11 distinct chromosomal regions controlling leaf rust resistance. Six of these regions may represent putative new QTL. Due to the elite parental material, RILs identified to be resistant to leaf rust can be easily introduced in breeding programs.

Identification of Rf9, a Gene Contributing to the Genetic Complexity of Fertility Restoration in Hybrid Wheat

Wheat (Triticum aestivum L.) is a self-pollinating crop whose hybrids offer the potential to provide a major boost in yield. Male sterility induced by the cytoplasm of Triticum timopheevii is a powerful method for hybrid seed production. Hybrids produced by this method are often partially sterile, and full fertility restoration is crucial for wheat production using hybrid cultivars. To identify the genetic loci controlling fertility restoration in wheat, we produced two cytoplasmic male-sterile (CMS) backcross (BC1) mapping populations. The restorer lines Gerek 79 and 71R1203 were used to pollinate the male-sterile winter wheat line CMS-Sperber. Seed set and numbers of sterile spikelets per spike were evaluated in 340 and 206 individuals of the populations derived from Gerek 79 and 71R1203, respectively. Genetic maps were constructed using 930 and 994 single nucleotide polymorphism (SNP) markers, spanning 2,160 and 2,328 cM over 21 linkage groups in the two populations, respectively. Twelve quantitative trait loci (QTL) controlled fertility restoration in both BC1 populations, including a novel restorer-of-fertility (Rf) locus flanked by the SNP markers IWB72413 and IWB1550 on chromosome 6AS. The locus was mapped as a qualitative trait in the BC1 Gerek 79 population and was designated Rf9. One hundred-nineteen putative candidate genes were predicted within the QTL region on chromosome 6AS. Among them were genes encoding mitochondrial transcription termination factor and pentatricopeptide repeat-containing proteins that are known to be associated with fertility restoration. This finding is a promising step to better understand the functions of genes for improving fertility restoration in hybrid wheat.

Usefulness of a Multiparent Advanced Generation Intercross Population With a Greatly Reduced Mating Design for Genetic Studies in Winter Wheat

Multiparent advanced generation intercross (MAGIC) populations were recently developed to allow the high-resolution mapping of quantitative traits. We present a genetic linkage map of an elite but highly diverse eight-founder MAGIC population in common wheat (Triticum aestivum L.). Our MAGIC population is composed of 394 F6:8 recombinant inbred lines lacking significant signatures of population structure. The linkage map included 5435 SNP markers distributed over 2804 loci and spanning 5230 cM. The analysis of population parameters, including genetic structure, kinship, founder probabilities, and linkage disequilibrium and congruency to other maps indicated appropriate construction of both the population and the genetic map. It was shown that eight-founder MAGIC populations exhibit a greater number of loci and higher recombination rates, especially in the pericentromeric regions, compared to four-founder MAGIC, and biparental populations. In addition, our greatly simplified eight-parental MAGIC mating design with an additional eight-way intercross step was found to be equivalent to a MAGIC design with all 210 possible four-way crosses regarding the levels of missing founder assignments and the number of recombination events. Furthermore, the MAGIC population captured 71.7% of the allelic diversity available in the German wheat breeding gene pool. As a proof of principle, we demonstrated the application of the resource for quantitative trait loci mapping analyzing seedling resistance to powdery mildew. As wheat is a crop with many breeding objectives, this resource will allow scientists and breeders to carry out genetic studies for a wide range of breeder-relevant parameters in a single genetic background and reveal possible interactions between traits of economic importance.

Considering causal genes in the genetic dissection of kernel traits in common wheat

Genetic factors controlling thousand-kernel weight (TKW) were characterized for their association with other seed traits, including kernel width, kernel length, ratio of kernel width to kernel length (KW/KL), kernel area, and spike number per m² (SN). For this purpose, a genetic map was established utilizing a doubled haploid population derived from a cross between German winter wheat cultivars Pamier and Format. Association studies in a diversity panel of elite cultivars supplemented genetic analysis of kernel traits. In both populations, genomic signatures of 13 candidate genes for TKW and kernel size were analyzed. Major quantitative trait loci (QTL) for TKW were identified on chromosomes 1B, 2A, 2D, and 4D, and their locations coincided with major QTL for kernel size traits, supporting the common belief that TKW is a function of other kernel traits. The QTL on chromosome 2A was associated with TKW candidate gene TaCwi-A1 and the QTL on chromosome 4D was associated with dwarfing gene Rht-D1. A minor QTL for TKW on chromosome 6B coincided with TaGW2-6B. The QTL for kernel dimensions that did not affect TKW were detected on eight chromosomes. A major QTL for KW/KL located at the distal tip of chromosome arm 5AS is being reported for the first time. TaSus1-7A and TaSAP-A1, closely linked to each other on chromosome 7A, could be related to a minor QTL for KW/KL. Genetic analysis of SN confirmed its negative correlation with TKW in this cross. In the diversity panel, TaSus1-7A was associated with TKW. Compared to the Pamier/Format bi-parental population where TaCwi-A1a was associated with higher TKW, the same allele reduced grain yield in the diversity panel, suggesting opposite effects of TaCwi-A1 on these two traits.

Genome-wide association mapping of preharvest sprouting resistance in a diversity panel of European winter wheats

Global wheat production will benefit from cultivars showing genetic resistance to preharvest sprouting (PHS). Working on PHS resistance is still challenging due to the lack of simple protocols for the provocation of symptoms for appropriate trait differentiation under highly variable environmental conditions. Therefore, the availability of molecular markers for enhancing PHS resistance in breeding lines is of utmost importance. Genome-wide association mapping was performed to unravel the genetics of PHS resistance in a diversity panel of 124 winter wheat genotypes using both random and targeted marker locus approaches. Data for grain germination tests, spike wetting treatments, and field sprouting damage measurements of grains were collected in 11, 12, and four environments, respectively. Twenty-two quantitative trait loci (QTL) linked with 40 markers were detected for the three traits commonly used for assessing the PHS resistance of cultivars. All but five QTL on chromosomes 1B, 1D (two QTL), 3D, and 5D showed locations similar to previous studies, including prominent QTL on chromosomes 2BS, 3AS, and 4AL. The highest retrieval rate across environments was found for QTL on chromosomes 1D, 2BS, 3D, 4AL, and 7B. The study identified genomic signatures useful for marker-assisted improvement of PHS resistance not only in European breeding programs, but of global significance.

Differential expression of THELPER 1 cytokines upon antigen stimulation predicts ex vivo proliferative potential and cytokine production of virus-specific T cells following re-stimulation

INTRODUCTION

Cytomegalovirus (CMV) and human adenovirus (ADV) infections are causes of morbidity after stem cell transplantation. Antigen (Ag)-specific T cells are essential for the control of viral infections. However, in vivo expansion potential of T-cell subpopulations is hardly predictable in humans. Furthermore, ex vivo identification of human T cells with repopulating capacity for adoptive T-cell transfer has been difficult.

METHODS

We analyzed Ag-specific T-cell populations, subdivided according to the expression of different THELPER- 1 (Th1) cytokines. Isolation by flow cytometry was based on interferon-gamma (IFN)-γ, interleukin (IL)-2, or tumor necrosis factor-alpha (TNF-α) secretion of T cells after ex vivo stimulation with the Ags hexon (for ADV) and pp65 (for CMV). Isolated T cells were expanded and examined for functional characteristics, expansion/differentiation potential, and naïve, effector memory, central memory, and late effector phenotypes.

RESULTS

Isolation based on IFN-γ production provides a T-cell population with a mixture of early, central memory, and effector memory T cells, high expansion potential, and effective cytokine production. Selection of T cells with Ag-specific expression of IL-2 or TNF-α, however, results in a T-cell population with reduced proliferation and lower effector potential after expansion.

CONCLUSION

We conclude that the exclusive secretion of IFN-γ in the human antiviral T-cell responses preferentially leads to higher repopulation capacities of antiviral T cells, compared to IL-2 or TNF-α secreting T-cell populations.

Pm50: a new powdery mildew resistance gene in common wheat derived from cultivated emmer

Fungal diseases of wheat, including powdery mildew, cause significant crop, yield and quality losses throughout the world. Knowledge of the genetic basis of powdery mildew resistance will greatly support future efforts to develop and cultivate resistant cultivars. Studies were conducted on cultivated emmer-derived wheat line K2 to identify genes involved in powdery mildew resistance at the seedling and adult plant growth stages using a BC(1) doubled haploid population derived from a cross between K2 and susceptible cultivar Audace. A single gene was located distal to microsatellite marker Xgwm294 on the long arm of chromosome 2A. Quantitative trait loci (QTL) analysis indicated that the gene was also effective at the adult plant stage, explaining up to 79.0 % of the variation in the progeny. Comparison of genetic maps indicated that the resistance gene in K2 was different from Pm4, the only other formally named resistance gene located on chromosome 2AL, and PmHNK54, a gene derived from Chinese germplasm. The new gene was designated Pm50.

Quantitative trait loci for adult-plant resistance to Mycosphaerella graminicola in two winter wheat populations

Septoria tritici blotch (STB) is one of the most important leaf spot diseases in wheat worldwide. The goal of this study was to detect chromosomal regions for adult-plant resistance in large winter wheat populations to STB. Inoculation by two isolates with virulence to Stb6 and Stb15, both present in the parents, was performed and STB severity was visually scored plotwise as percent coverage of flag leaves with pycnidia-bearing lesions. 'Florett'/'Biscay' and 'Tuareg'/'Biscay', each comprising a cross of a resistant and a susceptible cultivar, with population sizes of 316 and 269 F(7:8) recombinant inbred lines, respectively, were phenotyped across four and five environments and mapped with amplified fragment length polymorphism, diversity array technology, and simple sequence repeat markers covering polymorphic regions of ≈1,340 centimorgans. Phenotypic data revealed significant (P < 0.01) genotypic differentiation for STB, heading date, and plant height. Entry-mean heritabilities (h(2)) for STB were 0.73 for 'Florett'/'Biscay' and 0.38 for 'Tuareg'/'Biscay'. All correlations between STB and heading date as well as between STB and plant height were low (r = -0.13 to -0.20). In quantitative trait loci (QTL) analysis, nine and six QTL were found for STB ratings explaining, together, 55 and 51% of phenotypic variation in 'Florett'/'Biscay' and 'Tuareg'/'Biscay', respectively. Genotype-environment and QTL-environment interactions had a large impact. Two major QTL were detected consistently across environments on chromosomes 3B and 6D from 'Florett' and chromosomes 4B and 6B from 'Tuareg', each explaining 12 to 17% of normalized adjusted phenotypic variance. These results indicate that adult-plant resistance to STB in both mapping populations was of a quantitative nature.

A major QTL for resistance against Fusarium head blight in European winter wheat

We report on the verification of a resistance quantitative trait locus (QTL) on chromosome 1BL (now designated Qfhs.lfl-1BL) which had been previously identified in the winter wheat cultivar Cansas. For a more precise estimation of the QTL effect and its influence on plant height and heading date lines with a more homogeneous genetic background were created and evaluated in four environments after spray inoculation with Fusarium culmorum. Qfhs.lfl-1BL reduced FHB severity by 42% relative to lines without the resistance allele. This QTL did not influence plant height, but significantly delayed heading date by one day. All of the most resistant genotypes of the verification population carried this major QTL displaying its importance for disease resistance. This resistance QTL has not only been found in the cultivar Cansas, but also in the three European winter wheat cultivars Biscay, History and Pirat. A subsequent meta-analysis confirmed the presence of a single QTL on the long arm of chromosome 1B originating from the four mentioned cultivars. Altogether, the results of the present study indicate that Qfhs.lfl-1BL is an important component of FHB resistance in European winter wheat and support the view that this QTL would be effective and valuable in backcross breeding programmes.

Inheritance of resistance to Fusarium head blight in three European winter wheat populations

Fusarium head blight (FHB) resistance is of particular importance in wheat breeding programmes due to the detrimental effects of this fungal disease on human and animal health, yield and grain quality. Segregation for FHB resistance in three European winter wheat populations enabled the identification of resistance loci in well-adapted germplasm. Populations obtained from crosses of resistant cultivars Apache, History and Romanus with susceptible semi-dwarfs Biscay, Rubens and Pirat, respectively, were mapped and analysed to identify quantitative trait loci (QTL) for FHB severity, ear emergence time and plant height. The results of the present study together with previous studies in UK winter wheat indicated that the semi-dwarfing allele Rht-D1b seems to be the major source for FHB susceptibility in European winter wheat. The high resistance level of the cultivars Romanus and History was conditioned by several minor resistance QTL interacting with the environment and the absence of Rht-D1b. In contrast, the semi-dwarf parents contributed resistance alleles of major effects apparently compensating the negative effects of Rht-D1b on FHB reaction. The moderately resistant cultivar Apache contributed a major QTL on chromosome 6A in a genome region previously shown to carry resistance loci to FHB. A total of 18 genomic regions were repeatedly associated with FHB resistance. The results indicate that common resistance-associated genes or genomic regions are present in European winter wheats.

Marker-based introduction of three quantitative-trait loci conferring resistance to Fusarium head blight into an independent elite winter wheat breeding population

Fusarium head blight (FHB) is one of the most important wheat diseases that causes yield and quality losses as well as contamination with deoxynivalenol (DON). This study aimed for marker-based introduction of three previously mapped QTLs from two German winter wheat resistance sources into an elite background unrelated to the mapping population. A double cross (DC) served as initial population that combined two resistance donor-QTL alleles from "Dream" (Qfhs.lfl-6AL, Qfhs.lfl-7BS) and one donor-QTL allele from "G16-92" on chromosome 2BL with two high yielding, susceptible elite winter wheats ("Brando", "LP235.1"). The initial population of 600 DC-derived F(1) lines was selected with SSR markers for the respective QTLs. After two marker-selection steps, each of eight marker classes was represented by 9-22 lines possessing the respective donor-QTL allele or all possible combinations thereof in the homozygous state. The effect of the QTLs was estimated by field tests at four locations inoculated with Fusarium culmorum. Resistance was measured as the mean of multiple FHB ratings (0-100%). Marker classes incorporating only one QTL were not significantly more resistant than the class without any QTL, the combination of two donor-QTL alleles reduced FHB significantly. On average, lines with Qfhs.lfl-6AL were significantly taller than lines without this QTL. A considerable variation for FHB resistance was found in all marker classes. Marker-based introduction of two QTLs enhanced mean FHB rating by about 40 percentage points, the selected plants, however, were, on average, significantly taller. Both findings strongly support a phenotypic selection following after marker-based introduction of effective QTLs.

Mapping of extreme resistance to PVY (Ry (sto)) on chromosome XII using anther-culture-derived primary dihaploid potato lines

The inheritance of extreme resistance to PVY (Ry (sto)) by a single dominant locus was confirmed by obtaining a 1:1 segregation ratio in a virus inoculation test with 28 resistant (Ryry) to 29 susceptible (ryry) anther culture-derived dihaploid lines (2n=2x=24) from cv. "Assia" (2n=4x=48) having extreme resistance derived from Solanum stoloniferum in simplex constitution (Ryryryry). Twelve Ry (sto) markers selected in AFLP assays using bulked segregant analysis were applied to 106 tested potato cultivars from Germany, The Netherlands and Poland and 19 potato cultivars were identified by these markers as extremely resistant to PVY in alignment with phenotypic data. The locus for extreme resistance (Ry (sto)) to PVY was mapped on chromosome XII co-segregating with the SSR marker STM 0003. The utility of anther-culture derived dihaploid potatoes for genetic marker development was demonstrated. Marker transferability from diploids to tetraploids provides an optimistic potential for marker-assisted selection in potato breeding programs.

Molecular mapping of Fusarium head blight resistance in the winter wheat population Dream/Lynx

Fusarium head blight (FHB), mainly caused by Fusarium graminearum and F. culmorum, can significantly reduce the grain quality of wheat (Triticum aestivum L.) due to mycotoxin contamination. The objective of this study was to identify quantitative trait loci (QTLs) for FHB resistance in a winter wheat population developed by crossing the resistant German cultivar Dream with the susceptible British cultivar Lynx. A total of 145 recombinant inbred lines (RILs) were evaluated following spray inoculation with a F. culmorum suspension in field trials in 2002 in four environments across Germany. Based on amplified fragment length polymorphism and simple sequence repeat marker data, a 1,734 cM linkage map was established assuming that the majority of the polymorphic parts of the genome were covered. The area under disease progress curve (AUDPC) was calculated based on the visually scored FHB symptoms. The population segregated quantitatively for FHB severity. Composite interval mapping analysis for means across the environments identified four FHB resistance QTLs on chromosomes 6AL, 1B, 2BL and 7BS. Individually the QTLs explained 19%, 12%, 11% and 21% of the phenotypic variance, respectively, and together accounted for 41%. The QTL alleles conferring resistance on 6AL, 2BL and 7BS originated from cv. Dream. The resistance QTL on chromosome 6AL partly overlapped with a QTL for plant height. The FHB resistance QTL on 7BS coincided with a QTL for heading date, but the additive effect on heading date was of minor importance. The resistance QTL on chromosome 1B was associated with the T1BL.1RS wheat-rye translocation of Lynx.

QTL mapping for resistance against non-parasitic leaf spots in a spring barley doubled haploid population

Phenotypic variability for resistance against non-parasitic leaf spots (NPLS) has been observed between varieties. For the genetic characterization of NPLS resistance, a population with 430 doubled haploid (DH) lines was developed from the cross between the NPLS-resistant Hordeum vulgare breeding line IPZ24727 and the NPLS-sensitive barley cultivar Barke. A molecular map was constructed based on 164 AFLPs, 30 SSRs and one STS marker derived from the mlo gene. Field trials were performed over four environments in which NPLS and other agronomic traits were assessed. Estimates of genotypic variance were highly significant for NPLS. Moreover, no transgression was found for the trait. Quantitative trait loci (QTLs) for NPLS resistance were mapped in the DH population on chromosomes 1H, 4H, and 7H, with the most important effect on chromosome 4H. The QTLs for NPLS explained together 39% of the phenotypic and 49% of the genotypic variance, thereby showing additive gene action. Consequently, marker-assisted selection for improving NPLS resistance is possible.

Molecular mapping of QTLs for Fusarium head blight resistance in spring wheat. II. Resistance to fungal penetration and spread

Fusarium head blight (FHB, scab) causes severe yield and quality losses, but the most serious concern is the mycotoxin contamination of cereal food and feed. The cultivation of resistant varieties may contribute to integrated control of this fungal disease. Breeding for FHB resistance by conventional selection is feasible, but tedious and expensive. The aim of this work was to detect QTLs for combined type I and type II resistance against FHB and estimate their effects in comparison to the QTLs identified previously for type II resistance. A population of 364, F1 derived doubled-haploid (DH) lines from the cross 'CM-82036' (resistant)/'Remus' (susceptible) was evaluated for components of FHB resistance during 2 years under field conditions. Plants were inoculated at anthesis with a conidial suspension of Fusarium graminearum or Fusarium culmorum. The crop was kept wet for 20 h after inoculation by mist-irrigation. Disease severity was assessed by visual scoring. Initial QTL analysis was performed on 239 randomly chosen DH lines and extended to 361 lines for putative QTL regions. Different marker types were applied, with an emphasis on PCR markers. Analysis of variance, as well as simple and composite interval mapping, revealed that two genomic regions were significantly associated with FHB resistance. The two QTLs on chromosomes 3B (Qfhs.ndsu-3BS) and 5A (Qfhs.ifa-5A) explained 29 and 20% of the phenotypic variance, respectively, for visual FHB severity. Qfhs.ndsu-3BS appeared to be associated mainly with resistance to fungal spread, and Qfhs.ifa-5A primarily with resistance to fungal penetration. Both QTL regions were tagged with flanking SSR markers. These results indicate that FHB resistance was under the control of two major QTLs operating together with unknown numbers of minor genes. Marker-assisted selection for these two major QTLs appears feasible and should accelerate the development of resistant and locally adapted wheat cultivars.

Powdery mildew resistance gene Pm22 in cultivar Virest is a member of the complex Pm1 locus in common wheat ( Triticum aestivum L. em Thell.)

The powdery mildew resistance gene Pm22, identified in the Italian wheat cultivar Virest and originally assigned to wheat chromosome 1D, was mapped to chromosome 7A with the aid of molecular markers. Mapping of common AFLP and SSR markers in two wheat crosses segregating for Pm22 and Pm1c, respectively, indicated that Pm22 is a member of the complex Pm1 locus. Pm22 also showed a pattern of resistance reaction to a differential set of Blumeria graminis f. sp. tritici isolates that was distinguishable from those from other Pm1 alleles in lines Axminster/8*Cc ( Pm1a), MocZlatka ( Pm1b), Weihenstephan Stamm M1N ( Pm1c) and Triticum spelta var. duhamelianum TRI 2258 ( Pm1d). Based on these results, the gene symbol Pm1e is proposed for the powdery mildew resistance gene in cv. Virest.

Molecular mapping of QTLs for Fusarium head blight resistance in spring wheat. I. Resistance to fungal spread (Type II resistance)

Fusarium head blight (FHB, scab) is a fungal disease of wheat and other small cereals that is found in both temperate and semi-tropical regions. FHB causes severe yield and quality losses, but the most-serious concern is the possible mycotoxin contamination of cereal food and feed. Breeding for FHB resistance by conventional selection is feasible, but tedious and expensive. This study was conducted to identify and map DNA markers associated with FHB resistance genes in wheat. A population of 364 F(1)-derived doubled-haploid (DH) lines from the cross 'CM-82036' (resistant)/'Remus' (susceptible) was evaluated for Type II resistance (spread within the spike) during 2 years under field conditions. Marker analysis was performed on 239 randomly chosen DH lines. Different marker types were applied, with an emphasis on AFLP and SSR markers. Analysis of variance, as well as simple and composite interval mapping, were applied. Three genomic regions were found significantly associated with FHB resistance. The most-prominent effect was detected on the short arm of chromosome 3B, explaining up to 60% of the phenotypic variance for Type II FHB resistance. A further QTL was located on chromosome 5A and a third one on 1B. The QTL regions on 3B and 5A were tagged with flanking SSR markers, the 1B QTL was found associated with the high-molecular-weight glutenin locus. These results indicate that FHB resistance is under control of a few major QTLs operating together with unknown numbers of minor genes. Marker-assisted selection for these major QTLs involved in FHB resistance appears feasible and should accelerate the development of resistant and agronomically improved wheat cultivars.

Identification of AFLP markers closely linked to the powdery mildew resistance genes Pm1c and Pm4a in common wheat (Triticum aestivum L.)

A total of 7654 DNA fragments were screened for linkage to wheat powdery mildew resistance gene Pm1c employing fluorescently based AFLP analysis and phenotypic pools from F3 families. F3 and derived F4 families were used for segregation analysis. Pool screening revealed several cosegregating and tightly linked (0.9 cM) AFLP markers for the Pm1c resistance gene. The previously reported RFLP locus Xwhs178 was integrated into the AFLP map in the vicinity of Pm1c. One AFLP marker, 18M2, was determined to be highly specific for the Pm1c gene in diverse genetic backgrounds. As Pm1c allele confers an effective resistance to powdery mildew, the marker 18M2 provides a valuable tool for enhancing marker assisted selection and pyramiding of powdery mildew resistance genes in wheat.Key words: Triticum aestivum, powdery mildew, disease resistance, AFLP, bulked segregant analysis

[Psychophysiologic and psychologic correlates of the emotional family climate in schizophrenic patients and their family]

Within the framework of the vulnerability-stress model of schizophrenia, it is assumed that there is a specific relationship between the factors "expressed emotion" in the family of the patients and "psychophysological activation" of the patients. High expressed emotion would go together with a rise in psychophysiological activation. The aim of this study was to test whether psychophysiological correlates of an emotional family atmosphere could be found in the case of 2 schizophrenic patients in remission and their relatives (parents). The patients and their respective relatives were examined psychophysiologically during a baseline condition (alone), non-verbal interaction, and a discussion of relevant conflict areas. Among other things, three electrodermal parameters were recorded as autonomous measures of activation: SCL, number and amplitudes of nsSCs. The Camberwell Family Interview was used for assignment of EE. In addition, psyhopathological symptoms, reciprocal behavior assessment and agreement in various areas of life with self-assessment scales were recorded for patients and relatives. Despite the effectiveness of the experimental conditions, the EE categories were not reflected in any of the recorded measurements on the psychophysiological level. However, the EE categories were clearly reflected in the psychological parameters. HEE relatives proved to be less in agreement with others within the family, and they tended to be psychopathologically more conspicuous. The mutual behavior assessment for HEE couples was more negative than for LEE couples. The overlapping effects that could be a possible explanation of the psychophysiological findings and the results of the psychological correlates are discussed. Possibilities for improvement and further research strategies are suggested.

Comorbidity of anxiety disorders and hypochondriasis considering different diagnostic systems

The influence of different hierarchical guidelines in various classification systems on the diagnosis of anxiety disorders and hypochondriasis was investigated. Using a semistructured polydiagnostic interview (including DSM-III, DSM-III-R, and the 1987 draft version of ICD-10), lifetime diagnoses were determined in B2 outpatients with a DSM-III-R anxiety disorder. In all diagnostic systems, half of our patients exhibited the descriptive features of hypochondriasis. As demonstrated, the formulation of restrictive hierarchical rules--as in DSM-III--contributes to the concept of "primary" hypochondriasis, while secondary hypochondriasis remains underdiagnosed. Concordance rates for hypochondriasis were high between DSM-III-R and ICD-10, but not with DSM-III. Although hypochondriasis showed a strong association with the clinical course of panic disorder (PD), it could not be explained as a consequence of greater illness severity of PD with agoraphobia (AP). Our data underline the conceptualization of hypochondriasis as a phenomenologically homogeneous diagnostic category that may be differentiated from comorbid psychiatric conditions.

Molecular identification of powdery mildew resistance genes in common wheat (Triticum aestivum L.)

RFLP markers for the wheat powdery mildew resistance genes Pm1 and Pm2 were tagged by means of near-isogenic lines. The probe Whs178 is located 3 cM from the Pm1 gene. For the powdery mildew resistance gene Pm2, two markers were identified. The linkage between the Pm2 resistance locus and one of these two probes was estimated to be 3 cM with a F2 population. Both markers can be used to detect the presence of the corresponding resistance gene in commercial cultivars. "Bulked segregant analysis" was applied to identify linkage disequillibrium between the resistance gene Pm18 and the abovementioned marker, which was linked to this locus at a distance of 4 cM. Furthermore, the RAPD marker OPH-111900 (5'-CTTCCGCAGT-3') was selected with pools created from a population segregating for the resistance of 'Trigo BR 34'. The RAPD marker was mapped about 13 cM from this resistance locus.

Changes in physical symptoms, blood pressure and quality of life over 30 days

The existence of subjective symptoms arising from high blood pressure (BP) remains controversial. Few studies have been performed which compare symptoms of hypertensives and normotensives. The results of these studies are inconsistent. The present study investigates the intensities and prevalences of symptoms of hypertensives and normotensives and the relationship between symptoms and BP for both groups. During a 30-day period, 45 patients with primary hypertension and 45 normotensive controls documented BPs and intensities of 13 symptoms daily as well as mood and life satisfaction weekly. Starting on day 3 hypertensives received beta-blocker therapy (bopindolol, 1 mg/day). The BP values of the hypertensives normalized during the study, while the BPs of the normotensives did not change. At the beginning, hypertensives showed higher prevalences and intensities of the symptoms and poorer mood and life satisfaction. After normalization of BP, hypertensives attained scores similar to those of normotensives in all measured categories. Calculating within-S correlations between symptom intensities and systolic BPs, 70% of the hypertensives, but only 27% of the normotensives, showed at least one significant correlation. The differences observed between untreated hypertensives and the normotensive control group with respect to the prevalence and intensity of symptoms provide convincing evidence that untreated hypertensives are by no means symptom-free. The within-S correlations of the present study documented well the close relationship between symptoms and actual BP for a percentage of hypertensives.

Use of RFLP markers for the identification of alleles of the Pm3 locus conferring powdery mildew resistance in wheat (Triticum aestivum L.)

The objective of this study was to identify molecular markers linked to genes for resistance to powdery mildew (Pm) in wheat using a series of 'Chancellor' near-isogenic-lines (NILs), each having one powdery mildew resistance gene. A total of 210 probes were screened for their ability to detect polymorphism between the NILs and the recurrent parent. One of these restriction fragment length polymorphism (RFLP) markers (Xwhs179) revealed polymorphism not only between the NILs for the Pm3 locus, but also among NILs possessing different alleles of the Pm3 locus. The location of the marker Xwhs179 was confirmed to be on homoeologous chromosome group 1 with the help of nullitetrasomic wheat lines. The linkage relationship between this probe and the Pm3 locus was estimated with double haploid lines derived from a cross between wheat cvs 'Club' and 'Chul' (Pm3b). The genetic distance was determined to be 3.3±1.9 cM.

[Cardiovascular factors of cardiac phobia--a field study]

The interaction between psychological and physiological factors was studied with a field approach in 28 patients with cardiac phobia and 20 healthy controls. A 24-hour ambulatory ECG was recorded, and the subjects were instructed to report their activities and any cardiac perception during this period. Additionally, psychological tests assessing well-being (Bf-S), bodily complaints (B-L), and state and trait anxiety (Stai-S and Stai-T) were administered. The groups did not differ in the mean cardiovascular parameters, however patients with cardiac phobia and healthy controls showed clear differences in the strength and direction of correlations between psychological and physiological variables. The incidence of cardiac perceptions was about the same in both groups, but only patients with cardiac phobia attributed the perceptions to an internal stimulus and associated the perceptions with anxiety. Depending on the anxiety elicited by the cardiac perceptions, the patients with cardiac phobia showed heart rate accelerations, which did not occur in healthy controls. This study confirms a psychosomatic process between psychological and physiological variables, which seems to be able to explain the development and maintenance of cardiac phobia.

Heartbeat and arrhythmia perception in diabetic autonomic neuropathy

A comparative study of diabetics with autonomic neuropathy (N = 13) as against non-neuropathic diabetics (N = 16) and healthy control persons (N = 20) was carried out with respect to heart rate both at rest and under stress, frequency of cardiac arrhythmias in a 24-h ECG and accuracy of heartbeat and arrhythmia perception. In the subjects with diabetic autonomic neuropathy, the spontaneous variability and stress-induced reactivity of the heart rate as well as the number of tachycardic episodes were reduced, whereas the frequency of ventricular extrasystoles was somewhat increased. Impaired heartbeat perception and a complete loss of perception of arrhythmias as a consequence of neuropathic deafferentation could be demonstrated. Cardiac perception disorders also play a vital role in other clinical problems, e.g. silent myocardial infarction and lack of awareness of hypoglycaemia in diabetes mellitus.

Anxiety induced by cardiac perceptions in patients with panic attacks: a field study

In panic disorder bodily sensations appear to play an important role as a trigger for anxiety. In our psychophysiological model of panic attacks we postulate the following vicious circle: individuals with panic attacks perceive even quite small increases in heart rate and interpret these changes as being catastrophic. This elicits anxiety and a further increase in heart rate. To evaluate this model we conducted a field study of 28 subjects with panic attacks and 20 healthy controls. A 24 hr ambulatory ECG was recorded and the subjects were instructed to report any cardiac perceptions during this period and to rate the anxiety elicited by these perceptions. The incidence of cardiac perceptions was about the same in both groups, but only subjects with panic attacks reported anxiety associated with such perceptions. Analysis of the ECGs revealed that in both groups heart rate accelerations preceded cardiac perceptions. Following cardiac perceptions, the healthy controls showed a heart rate deceleration, whereas the subjects with panic attacks had a further acceleration. This heart rate increase after cardiac perceptions was positively related to the level of anxiety elicited by the perceptions. These results provide clear evidence in support of the vicious circle model of panic attacks.

Structural study of long arm fragments of laminin. Evidence for repetitive C-terminal sequences in the A-chain, not present in the B-chains

The outer segments of the long arm of laminin have recently been shown to mediate attachment of many cell types and to stimulate neurite outgrowth. For a structural characterization of this part of the molecule we prepared, by limited elastase digestion of laminin, fragments E3 and E8, previously identified as a globular heparin-binding domain and as a 35-nm-long rod with a terminal globule, respectively. Fragment E3 is a domain adjacent to fragment E8. Both structures together comprise the complete terminal half of the long arm. Our data confirm current models, which predict that the C-terminal segments from all three chains contribute to its structure. The B chains terminate at the end of the rod like domain, while the large terminal globule is formed by A-chain structures only. In addition to fragment E3, two new fragments T1 and T2 obtained by tryptic cleavage of fragment E8 were characterized as substructures of the globular domain. Screening of a mouse cDNA library with synthetic oligonucleotides allowed isolation of an 1.8-kb cDNA clone encoding 547 C-terminal amino acids of the A chain and some 196 nucleotides of the 3'-untranslated region including a single polyadenylation site. The clone contained portions of domain T2 and the complete heparin binding domain E3 which was thus identified as the most C-terminal domain of the A chain. Sequence alignment indicated that the terminal globule is formed by homologous repeats of some 140 residues having no counterpart in the B chains.

The N terminus of laminin A chain is homologous to the B chains

A major proteolytic fragment (E1/E1-4) of the basement membrane protein laminin, comprising the three short arms with some terminal globules missing, was isolated by elastase digestion, and partial protein sequence data were determined for several tryptic peptides. Sequences which corresponded to A-chain structures were used to synthesize oligonucleotides for the construction and screening of a primer-extended cDNA library from mouse PYS-2 cells. A clone of 1.1 kb was obtained and shown by sequencing to correspond to the 5' end of the 10-kb mRNA of the A chain of laminin. The clone contains 77 nucleotides of 5' untranslated sequence and a region coding for 334 amino acids, including a presumptive signal peptide of 24 amino acids. The sequence is 30% homologous to the corresponding N-terminal part of the B1 chain of laminin, suggesting the same structure for both domains. The data present further evidence for a recent structural model which postulates that each of the three laminin polypeptide chains forms a distinct short arm.