Newest publications
Large-scale genotyping and phenotyping of a worldwide winter wheat genebank for its use in pre-breeding
(2022) Schulthess, Albert W.; Kale, Sandip M.; Zhao, Yusheng; Gogna, Abhishek; Rembe, Maximilian; Philipp, Norman; Liu, Fang; Beukert, Ulrike; Serfling, Albrecht; Himmelbach, Axel; Oppermann, Markus; Weise, Stephan; Boeven, Philipp H. G.; Schacht, Johannes; Longin, C. Friedrich H.; Kollers, Sonja; Pfeiffer, Nina; Korzun, Viktor; Fiebig, Anne; Schüler, Danuta; Lange, Matthias; Scholz, Uwe; Stein, Nils; Mascher, Martin; Reif, Jochen C.
Plant genetic resources (PGR) stored at genebanks are humanity’s crop diversity savings for the future. Information on PGR contrasted with modern cultivars is key to select PGR parents for pre-breeding. Genotyping-by-sequencing was performed for 7,745 winter wheat PGR samples from the German Federal ex situ genebank at IPK Gatersleben and for 325 modern cultivars. Whole-genome shotgun sequencing was carried out for 446 diverse PGR samples and 322 modern cultivars and lines. In 19 field trials, 7,683 PGR and 232 elite cultivars were characterized for resistance to yellow rust - one of the major threats to wheat worldwide. Yield breeding values of 707 PGR were estimated using hybrid crosses with 36 cultivars - an approach that reduces the lack of agronomic adaptation of PGR and provides better estimates of their contribution to yield breeding. Cross-validations support the interoperability between genomic and phenotypic data. The here presented data are a stepping stone to unlock the functional variation of PGR for European pre-breeding and are the basis for future breeding and research activities.
Between trust and ambivalence: how does trainee teachers’ perception of the relationship with their mentors explain how trainee teachers experience their work?
(2024) Maué, Elisabeth; Goller, Michael; Bonnes, Caroline; Kärner, Tobias
The study aims to identify profiles of trainee teachers in terms of their stress and work experiences and to uncover profile differences in regard to dropout intentions and perceived relationships between trainee teachers and their mentors. Based on data from 1,756 German trainee teachers, three distinct stress and work experience profiles could be identified. Trainee teachers with high levels of stress and negative work experiences exhibit higher dropout intentions and experience their relationship with their mentors as less transparent, fair and trusting, and more ambivalent compared to trainee teachers with low levels of stress and positive work experiences. The results underline the importance of the relationship between mentors and trainee teachers for the professional development of future teachers.
Competitive hierarchies in bryozoan assemblages mitigate network instability by keeping short and long feedback loops weak
(2023) Koch, Franziska; Neutel, Anje-Margriet; Barnes, David K. A.; Tielbӧrger, Katja; Zarfl, Christiane; Allhoff, Korinna T.
Competitive hierarchies in diverse ecological communities have long been thought to lead to instability and prevent coexistence. However, system stability has never been tested, and the relation between hierarchy and instability has never been explained in complex competition networks parameterised with data from direct observation. Here we test model stability of 30 multispecies bryozoan assemblages, using estimates of energy loss from observed interference competition to parameterise both the inter- and intraspecific interactions in the competition networks. We find that all competition networks are unstable. However, instability is mitigated considerably by asymmetries in the energy loss rates brought about by hierarchies of strong and weak competitors. This asymmetric organisation results in asymmetries in the interaction strengths, which reduces instability by keeping the weight of short (positive) and longer (positive and negative) feedback loops low. Our results support the idea that interference competition leads to instability and exclusion but demonstrate that this is not because of, but despite, competitive hierarchy.
Drought impacts on plant–soil carbon allocation - integrating future mean climatic conditions
(2025) Leyrer, Vinzent; Blum, Juliette; Marhan, Sven; Kandeler, Ellen; Zimmermann, Telse; Berauer, Bernd J.; Schweiger, Andreas H.; Canarini, Alberto; Richter, Andreas; Poll, Christian
Droughts affect soil microbial abundance and functions—key parameters of plant–soil carbon (C) allocation dynamics. However, the impact of drought may be modified by the mean climatic conditions to which the soil microbiome has previously been exposed. In a future warmer and drier world, effects of drought may therefore differ from those observed in studies that simulate drought under current climatic conditions. To investigate this, we used the field experiment ‘Hohenheim Climate Change,’ an arable field where predicted drier and warmer mean climatic conditions had been simulated for 12 years. In April 2021, we exposed this agroecosystem to 8 weeks of drought with subsequent rewetting. Before drought, at peak drought, and after rewetting, we pulse‐labelled winter wheat in situ with 13CO2 to trace recently assimilated C from plants to soil microorganisms and back to the atmosphere. Severe drought decreased soil respiration (−35%) and abundance of gram‐positive bacteria (−15%) but had no effect on gram‐negative bacteria, fungi, and total microbial biomass C. This pattern was not affected by the mean precipitation regime to which the microbes had been pre‐exposed. Reduced mean precipitation had, however, a legacy effect by decreasing the proportion of recently assimilated C allocated to the microbial biomass C pool (−50%). Apart from that, continuous soil warming was an important driver of C fluxes throughout our experiment, increasing plant biomass, root sugar concentration, labile C, and respiration. Warming also shifted microorganisms toward utilizing soil organic matter as a C source instead of recently assimilated compounds. Our study found that moderate shifts in mean precipitation patterns can impose a legacy on how plant‐derived C is allocated in the microbial biomass of a temperate agroecosystem during drought. The overarching effect of soil warming, however, suggests that how temperate agroecosystems respond to drought will mainly be affected by future temperature increases.
Enzymatically formed fatty acid hydroperoxides determined through GC‐MS analysis of enantiomeric excess of hydroxy fatty acids after reduction and ibuprofen derivatization
(2025) Hotz, Lisa; Zartmann, Anne; Noack, Isabelle; Drees, Luca J.; Kuschow, Meret K.; Heinrich, Markus R.; Janssen, Hans‐Gerd; Hammann, Simon
Unsaturated fatty acids are susceptible to lipid oxidation through autoxidation, photooxygenation or enzymatical oxidation. A characteristic feature of enzyme‐catalyzed oxidation is the high regio‐ and stereospecificity of the formed fatty acid hydroperoxides. In this study, we present a method to quantify enzymatic lipid oxidation through reducing hydroperoxy fatty acid methyl esters to hydroxy fatty acid methyl esters and derivatizing them with enantiopure (S)‐ibuprofen, allowing the resolution of the enantiomer pairs as diastereomers via achiral GC‐MS. After application to enantiopure reference fatty acids, the approach was applied to autoxidation products of linoleic acid, and the expected racemic mixtures of the 9‐ and 13‐hydroperoxide derived hydroxy fatty acids were detected. On the other hand, when linoleic acid was oxidized using soybean lipoxygenase, clear enantiomeric excess of the (13S) enantiomer could be detected, proving the applicability of this method to detect enzymatic oxidation through enantiomeric excess.