Sondersammlungen
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Publication Antiviral defense systems in the rumen microbiome(2025) Sáenz, Johan S.; Rios-Galicia, Bibiana; Seifert, JanaThe continuous interaction between phages and their respective hosts has resulted in the evolution of multiple bacterial immune mechanisms. However, the diversity and prevalence of antiviral defense systems in complex communities are still unknown. We therefore investigated the diversity and abundance of viral defense systems in 3,038 high-quality bacterial and archaeal genomes from the rumen. In total, 14,241 defense systems and 31,948 antiviral-related genes were identified. Those genes represented 114 unique system types grouped into 49 families. We observed a high prevalence of defense systems in the genomes. However, the number of defense systems, defense system families, and system density varied widely from genome to genome. Additionally, the number of defense system per genome correlated positively with the number of defense system families and the genome size. Restriction modification, Abi, and cas system families were the most common, but many rare systems were present in only 1% of the genomes. Antiviral defense systems are prevalent and diverse in the rumen, but only a few are dominant, indicating that most systems are rarely present. However, the collection of systems throughout the rumen may represent a pool of mechanisms that can be shared by different members of the community and modulate the phage–host interaction.Publication Chloride application enhances photosynthesis and facilitates nitrate translocation while driving chloride translocation into roots(2025) Wei, Guanghui; Zhang, Xudong; Franzisky, Bastian L.; Geilfus, Christoph‐Martin; Zörb, ChristianChloride and nitrate are essential mineral elements for crop growth. Due to their similar physical and electrochemical properties, their uptake and translocation interact antagonistically. This suggests that applying chloride to the leaf canopy during the late grain‐filling stage of cereals might enhance nitrate use efficiency. Hence, it remains uncertain whether foliar‐applied chloride at the late growth stage stimulates nitrate translocation from mature to younger leaves. To explore this possibility, two contrasting faba bean varieties were grown in a climate‐controlled chamber. Nitrate concentrations of approximately 50 and 93 μg mg FW −1 , respectively, were established in leaves by depleting nitrogen in the rooting medium. Based on these two nitrate concentrations in mature leaves, chloride was applied to the leaf canopy. Measurements of biomass, photosynthesis, and nitrate and chloride concentrations in both young and mature leaves revealed that chloride foliar application raised nitrate levels in younger leaves from 7.1 to 9.5 μmol g FW −1 and boosted photosynthesis by approximately 35%. However, one of the two faba bean varieties did not respond significantly to the chloride foliar application. These findings indicate that chloride application facilitates nitrate translocation from mature to younger leaves, potentially improving grain nitrogen supply. As a result, nitrate use efficiency might be increased by chloride application during late growth stages, although this effect is genotype‐dependent.Publication Comparative ungulate diversity and biomass change with human use and drought: implications for community stability and protected area prioritization in African savannas(2025) Bartzke, Gundula S.; Ogutu, Joseph O.; Piepho, Hans‐Peter; Bedelian, Claire; Rainy, Michael E.; Kruska, Russel L.; Worden, Jeffrey S.; Kimani, Kamau; McCartney, Michael J.; Ng'ang'a, Leah; Kinoti, Jeniffer; Njuguna, Evanson C.; Wilson, Cathleen J.; Lamprey, Richard; Hobbs, Nicholas Thompson; Reid, Robin S.Drought and human use may alter ungulate diversity and biomass in contrasting ways. In African savannas, resource‐dependent grazers such as wildebeest (Connochaetes taurinus) and zebra (Equus quagga) may decline or disperse as resources decline, opening space for more drought‐tolerant species such as gazelles (Eudorcas and Nanger) and impala (Aepyceros melampus). This shift can increase species richness, evenness, and overall ungulate diversity. Although higher diversity may stabilize ungulate communities, it may be associated with lower biomass (the total body mass of all individuals in a community), which in turn affects vegetation structure and composition, nutrient cycling, energy flows, and other organisms in savannas. While ungulate biomass often declines during drought or in areas of intense human use, the effects on diversity changes under low‐to‐moderate human use remain less clear. Our fine‐scale censuses in the Maasai Mara National Reserve and adjacent pastoral lands in Kenya showed that ungulate biomass declined more than diversity in the 1999 drought year. In the normal rainfall year of 2002, diversity peaked along the reserve boundary, but species richness leveled off in the drought year. Biomass peaked in the reserve in both census years, and migratory ungulates moved further into the reserve in the drought year, where diversity declined. These findings suggest that core protected areas are crucial for maintaining ungulate biomass, while transition zones from protected and pastoral lands support higher diversity unless drought reduces species richness.Publication Data on transgenerational memory effects of photosynthetic efficiency of twelve wheat varieties under elevated carbon dioxide concentration and reduced soil water availability(2025) Berauer, Bernd J.; Chaudhary, Suraj; Kottmann, Lorenz; Schweiger, Andreas H.This data represents ACi curves of twelve winter wheat varieties, which were grown under elevated and ambient CO2 concentrations within a FACE experiment and the subsequent F1 generation was exposed to ambient and elevated CO2 concentrations in a highly controlled environment using climate chambers. The 12 winter wheat genotypes (Triticum aestivum L.) were selected based on their susceptibilty to leaf rust (Puccinia triticina Eriks.) and Fusarium head blight (Fusarium graminearum Schwabe) according to the descriptive variety list of the German Federal Office of Plant Varietes (Beschreibende Sortenliste, Bundessortenamt 2024). The aim was to obtain a diverse set of varieties with the widest possible range of susceptibilities to leaf rust and fusarium head blight. Photosynthesis was measured using the novel Dynamic Assimilation Technique, thus not with the common steady-state approach. The individual wheat plants were measured twice, once under saturating soil water availability (θFC) and once under reduced soil water availability (θcsoil). θcsoil represents the gravimetric water content when the soil matric potential drops below the root matric potential, thus the onset of plant drought stress (sensu Cai et al. [2]). The photosynthesis data was used to fit ACi curves and extract the maximum Rubisco carboxylation rate [Vcmax], maximum rate of electron transport [Jmax] and dark respiration [Rd]. At both measurements we determined BBCH and plant height to quantify plant morphological development, as well as leaf water potential to quantify plant ecohydrologic status. At the end of the experiment, biomass was harvested and reported. Further, we provide environmental data of the climate chambers in use. Within the data repository, we provide comprehensive experimental data on the investigation of transgenerational memory effects on photosynthetic efficiency. We provide photosynthetic raw data as well as processed (merged) and derived (extracted ACi fit) data. Additionally, we provide the R-code to reproduce the calculation of the derived parameters. Data on transgenerational memory effects (that is, the influence of the parental environment on offspring phenotype and performance) are scarce, i.e. on the adaptive capacity of the photosynthetic apparatus. Thus, the data provided here can contribute to closing this gap. The highly controlled environment allows to closely investigate cause-effect relationships, thereby contributing to a mechanistic understanding of the transgenerational memory effects on photosynthetic efficiency and how this is altered by reduced soil water availability. By using a recently developed methodological approach, the data contributes to further investigate the quality of the method and establish it within the field of plant ecophysiology.Publication A diamine oxidase from Glutamicibacter halophytocola for the degradation of histamine and tyramine in foods(2025) Kettner, Lucas; Freund, Alexander; Bechtel, Anna; Costa-Catala, Judit; Fischer, LutzA novel diamine oxidase (DAO) was discovered in the bacterium Glutamicibacter halophytocola (DAO-GH). The gene of DAO-GH was integrated into the genome of the yeast Komagataella phaffii and recombinantly produced under control of the methanol-inducible AOX1 promoter in a bioreactor cultivation. A high DAO activity of 70.2 ± 5.2 µkat/Lculture (5.25 ± 0.22 µkat/gprotein) was yielded after 90 h of cultivation. The DAO-GH was partially purified by the polyethyleneimine precipitation of nucleic acids, fractionated ammonium sulfate precipitation and hydrophobic interaction chromatography, resulting in a specific DAO activity of 19.7 µkat/gProtein. The DAO-GH was then biochemically investigated regarding its potential for histamine and tyramine degradation in fermented foods and the human small intestine. Interestingly, the DAO-GH showed activity even at a low pH of 5 and low temperature of 6 °C. Both histamine and tyramine were effectively degraded and DAO-GH showed especially very high affinity towards tyramine (Km of 0.009 mM). The DAO-GH was shown to be capable of degrading around 20% of the initially applied histamine in tuna paste (pH 5.6) at 5 °C within 24 h and completely degraded the histamine in a simulated intestinal fluid within 1.5 h in bioconversion experiments. The DAO-GH was spray-dried for the production of a storable enzyme preparation. Only around 17% of activity were lost in this process and the DAO-GH remained stable at room temperature for at least 3 months. The discovery of this DAO with its very advantageous biochemical properties allows the preparation of histamine-reduced or -free fermented foods by a simple enzymatic treatment or the treatment of histamine intolerance symptoms as a dietary supplement or medicine.Publication Enhanced crop diversity but not smaller field size benefit bats in agricultural landscapes(2025) Hiller, Thomas; Gall, Friederike; Grass, IngoContext: Farmland biodiversity continues to decline due to the expansion and intensification of agriculture. Historically, efforts to conserve farmland biodiversity have focused on conserving habitats outside agricultural production areas. More recently, attention has turned to the conservation potential of the cropland matrix, where reducing field size and increasing crop diversity to promote crop heterogeneity can significantly benefit farmland biodiversity. Bats are one group of farmland species that have experienced dramatic declines over recent decades. Objectives: Here we investigated the effects of crop heterogeneity (crop diversity, field size) and landscape structural elements (e.g. length of linear structures, distance to forest, proportion of semi-natural habitat) on the activity of bat functional groups. Results: Increasing crop diversity led to greater bat activity, especially for open space foraging bats. However, contrary expectations, bat activity was not affected by heterogeneity in crop configuration, i.e. field edge density. Furthermore, structural landscape elements, including hedgerows and distance to forest, were important predictors of bat activity, especially for species that hunt in highly cluttered spaces. While crop diversity clearly benefited bat activity, the lack of effect of crop configurational heterogeneity on bat foraging activity may suggest heterogeneityarea trade-offs and intensive pesticide use in small-scale vegetable production. Conclusions: Therefore, in addition to maintaining high levels of crop diversity, promoting hedgerows and tree lines between farmland and woodland may facilitate bat activity across the agricultural landscape matrix. The combination of high crop heterogeneity and structural elements provides favorable hunting grounds for bats and may promote their conservation in agricultural landscapes.Publication Insect conservation in agricultural landscapes needs both high crop heterogeneity and semi-natural habitats(2024) Tassoni, Sara; Becker, David; Kasten, Marit Kinga; Moriníere, Jérôme; Grass, IngoIdentifying landscapes that are suitable for both biodiversity conservation and agricultural production is a major challenge. Traditionally, much research has focused on biodiversity conservation outside of agricultural production areas, e.g., in semi-natural habitats. In contrast, recent research has mainly focused on the potential of crop heterogeneity. This includes both compositional (crop diversity) and configurational heterogeneity (field border density). However, if and how crop heterogeneity, and semi-natural habitats interact to shape insect diversity in agricultural landscapes remains poorly understood. Here we investigated the combined effects of crop diversity, field border density, and semi-natural habitats (i.e., grassland proportion, hedge density) on insect diversity. We sampled insect communities from 14 – 17 June 2021 with pan traps in 27 study landscapes (500 m x 500 m) covering independent gradients of these landscape variables and identified a total of 587 insect species with DNA metabarcoding. We found that field border density mediated the effects of crop diversity, grassland proportion, and hedge density on insect richness. At low levels of field border density (i.e., landscapes with mostly large fields), effects were either neutral (crop diversity), negative (grassland proportion) or weakly positive (hedge density). By contrast, at high levels of field border density, crop diversity, grassland proportion, and hedge density all exerted positive effects on insect richness. Responses to crop heterogeneity and semi-natural habitat differed among trophic groups of insects (decomposers, herbivores, parasitoids, predators). While variation in richness of herbivorous insects followed the patterns of the overall richness, decomposer richness was not related to any of the investigated variables. Predator richness increased with hedge density in landscapes, whereas parasitoid richness increased when high levels of field border density and grassland proportion coincided. Our study shows that increasing crop heterogeneity is a viable strategy for promoting insect diversity in agricultural landscapes. However, the effects of the amount of remaining semi-natural habitats, such as grassland or hedges, are mediated by configurational heterogeneity, and vary between trophic groups. Efforts to conserve insects in agricultural landscapes must therefore focus on both increasing the heterogeneity of the crop matrix by promoting crop diversity and increasing the density of field borders, while also maintaining or restoring semi-natural habitats as important source habitats for insect species.Publication Mating-type analysis in Diaporthe isolates from soybean in central Europe(2025) Hosseini, Behnoush; Käfer, Lena Sophia; Link, Tobias Immanuel; Cai, LeiSpecies of the genus Diaporthe have a mating-type system with the two mating types MAT1-1 and MAT1-2, like other ascomycetes. They can either be heterothallic, which means that any isolate only possesses one of the two mating types and needs a mating partner for sexual reproduction, or homothallic, which means that they possess both mating types and are self-fertile. For several Diaporthe species, no sexual reproduction has been observed so far. Using PCR with primers specific to the defining genes MAT1-1-1 and MAT1-2-1 , we determined the mating types of 33 isolates of Diaporthe caulivora , D. eres , D. longicolla , and D. novem from central Europe. In addition, we partially sequenced the mating-type genes of 25 isolates. We found that different D. longicolla isolates either possess MAT1-1-1 or MAT1-2-1, making the species heterothallic, which is in contrast to previous studies and the general assumption that D. longicolla only reproduces asexually. D. eres and D. novem were also found to be heterothallic. Using genomic sequence information and re-sequencing of DNA and RNA, we identified the MAT1-1-1 gene in D. caulivora and present here the full sequence of the mating-type locus of this homothallic species. Finally, we used sequence information from MAT1-1-1 and MAT1-2-1 , respectively, for improved phylogenetic resolution of our isolates.Publication Metabolome fingerprinting reveals the presence of multiple nitrification inhibitors in biomass and root exudates of Thinopyrum intermedium(2024) Issifu, Sulemana; Acharya, Prashamsha; Schöne, Jochen; Kaur-Bhambra, Jasmeet; Gubry-Rangin, Cecile; Rasche, FrankBiological Nitrification Inhibition (BNI) encompasses primarily NH4 +-induced release of secondary metabolites to impede the rhizospheric nitrifying microbes from per- forming nitrification. The intermediate wheatgrass Thinopyrum intermedium (Kernza®) is known for exuding several nitrification inhibition traits, but its BNI potential has not yet been identified. We hypothesized Kernza® to evince BNI potential through the presence and release of multiple BNI metabolites. The presence of BNI metabolites in the biomass of Kernza® and annual winter wheat (Triticum aestivum) and in the root exudates of hydroponically grown Kernza®, were fingerprinted using HPLC-DAD and GC–MS/MS analyses. Growth bioassays involving ammonia-oxidizing bacteria (AOB) and archaea (AOA) strains were conducted to assess the influence of the crude root metabolome of Kernza® and selected metabolites on nitrification. In most instances, significant concentrations of various metabolites with BNI potential were observed in the leaf and root biomass of Kernza® compared to annual winter wheat. Furthermore, NH4 + nutrition triggered the exudation of various phenolic BNI metabolites. Crude root exudates of Kernza® inhibited multiple AOB strains and completely inhibited N. viennensis. Vanillic acid, caffeic acid, vanillin, and phenylalanine suppressed the growth of all AOB and AOA strains tested, and reduced soil nitrification, while syringic acid and 2,6-dihydroxybenzoic acid were ineffective. We demonstrated the considerable role of the Kernza® metabolome in suppressing nitrification through active exudation of multiple nitrification inhibitors.Publication The non-nutritive sweetener rebaudioside a enhances phage infectivity(2025) Marongiu, Luigi; Brzozowska, Ewa; Brykała, Jan; Burkard, Markus; Schmidt, Herbert; Szermer-Olearnik, Bożena; Venturelli, SaschaNon-nutritive sweeteners (NNS) are widely employed in foodstuffs. However, it has become increasingly evident that their consumption is associated with bacterial dysbiosis, which, in turn, is linked to several health conditions, including a higher risk of type 2 diabetes and cancer. Among the NNS, stevia, whose main component is rebaudioside A (rebA), is gaining popularity in the organic food market segment. While the effect of NNS on bacteria has been established, the impact of these sweeteners on bacterial viruses (phages) has been neglected, even though phages are crucial elements in maintaining microbial eubiosis. The present study sought to provide a proof-of-concept of the impact of NNS on phage infectivity by assessing the binding of rebA to phage proteins involved in the infection process of enteropathogenic bacteria, namely the fiber protein gp17 of Yersinia enterocolitica phage φYeO3-12 and the tubular baseplate protein gp31 of Klebsiella pneumoniae phage 32. We employed docking analysis and a panel of in vitro confirmatory tests (microscale thermophoresis, RedStarch ™ depolymerization, adsorption, and lysis rates). Docking analysis indicated that NNS can bind to both fiber and baseplate proteins. Confirmatory assays demonstrated that rebA can bind gp31 and that such binding increased the protein’s enzymatic activity. Moreover, the binding of rebA to gp17 resulted in a decrease in the adsorption rate of the recombinant protein to its host but increased the Yersinia bacteriolysis caused by the whole phage compared to unexposed controls. These results support the hypothesis that NNS can impair phage infectivity, albeit the resulting effect on the microbiome remains to be elucidated.