@article{KraussVikukYoungetal.2020, author = {Krauss, Jochen and Vikuk, Veronika and Young, Carolyn A. and Krischke, Markus and Mueller, Martin J. and Baerenfaller, Katja}, title = {Epichlo{\"e} endophyte infection rates and alkaloid content in commercially available grass seed mixtures in Europe}, series = {Microorganisms}, volume = {8}, journal = {Microorganisms}, number = {4}, issn = {2076-2607}, doi = {10.3390/microorganisms8040498}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203323}, pages = {498}, year = {2020}, abstract = {Fungal endophytes of the genus Epichlo{\"e} live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichlo{\"e} infected grasses, the inclusion of Epichlo{\"e} in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichlo{\"e} infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichlo{\"e} endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichlo{\"e} infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichlo{\"e} festucae var. lolii infecting Lolium perenne. As Epichlo{\"e} infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichlo{\"e} infection status or avoiding Epichlo{\"e} infected seed mixtures.}, language = {en} } @article{KraussVikukYoungetal.2020, author = {Krauss, Jochen and Vikuk, Veronika and Young, Carolyn A. and Krischke, Markus and Mueller, Martin J. and Baerenfaller, Katja}, title = {Correction: Krauss, J., et al. Epichlo{\"e} endophyte infection rates and alkaloid content in commercially available grass seed mixtures in Europe. Microorganisms 2020, 8, 498}, series = {Microorganisms}, volume = {8}, journal = {Microorganisms}, number = {10}, issn = {2076-2607}, doi = {10.3390/microorganisms8101616}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216254}, year = {2020}, abstract = {No abstract available.}, language = {en} } @article{ThurowKrischkeMuelleretal.2020, author = {Thurow, Corinna and Krischke, Markus and Mueller, Martin J. and Gatz, Christiane}, title = {Induction of jasmonoyl-isoleucine (JA-Ile)-dependent JASMONATE ZIM-DOMAIN (JAZ) genes in NaCl-treated Arabidopsis thaliana roots can occur at very low JA-Ile levels and in the absence of the JA/JA-Ile transporter JAT1/AtABCG16}, series = {Plants}, volume = {9}, journal = {Plants}, number = {12}, issn = {2223-7747}, doi = {10.3390/plants9121635}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219382}, year = {2020}, abstract = {The plant hormone jasmonoyl-isoleucine (JA-Ile) is an important regulator of plant growth and defense in response to various biotic and abiotic stress cues. Under our experimental conditions, JA-Ile levels increased approximately seven-fold in NaCl-treated Arabidopsis thaliana roots. Although these levels were around 1000-fold lower than in wounded leaves, genes of the JA-Ile signaling pathway were induced by a factor of 100 or more. Induction was severely compromised in plants lacking the JA-Ile receptor CORONATINE INSENSITIVE 1 or enzymes required for JA-Ile biosynthesis. To explain efficient gene expression at very low JA-Ile levels, we hypothesized that salt-induced expression of the JA/JA-Ile transporter JAT1/AtABCG16 would lead to increased nuclear levels of JA-Ile. However, mutant plants with different jat1 alleles were similar to wild-type ones with respect to salt-induced gene expression. The mechanism that allows COI1-dependent gene expression at very low JA-Ile levels remains to be elucidated.}, language = {en} } @phdthesis{Zhu2020, author = {Zhu, Mo}, title = {Germination and differentiation of \(Blumeria\) \(graminis\) ascospores and effects of UV-C and white light irradiation on \(B.\) \(graminis\) conidial prepenetration}, doi = {10.25972/OPUS-16647}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166470}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {Blumeria graminis, the obligate biotrophic grass powdery mildew, is a highly pathogenic fungus capable of inflicting foliar diseases and of causing severe yield losses. There is asexual and sexual propagation in the life cycle of B. graminis. In the epidemiological processes of this pathogen, both types of spores - asexual conidia and sexual ascospores - are crucial. Conidia of B. graminis are demonstrated to perceive cuticular very-long-chain aldehydes as molecular signal substances notably promoting germination and differentiation of the infection structure (the appressorium) - the prepenetration processes - in a concentration- and chain-length-dependent manner. Conidial germination and appressorium formation are known to be dramatically impeded by the presence of free water on the host surface. However, sexually formed ascospores are reported to easily germinate immersed in water. There are abundant assays on conidial prepenetration processes. However, with respect to the stimulating effects of very-long-chain aldehydes and to the influence of the presence of free water, ascosporic prepenetration processes are still obscure. In order to study the effects of very-long-chain aldehydes on the ascosporic prepenetration processes of wheat powdery mildew fungus B. graminis f. sp. tritici, Formvar®-based in vitro systems were applied to exclude the secondary host effects (such as host resistance) and to reproducibly provide homogeneous hydrophobic substratum surfaces. By the presence of even-numbered very-long-chain aldehydes (C22 - C30), the appressorium formation of the ascospores was notably triggered in a chain-length dependent manner. N-octacosanal (C28) was the most inducing aldehyde tested. Unlike conidia, ascospores could easily differentiate immersed in water and showed a more variable differentiation pattern even with a single germ tube differentiating an appressorium. To evaluate the alternative management against barley powdery mildew fungus Blumeria graminis f. sp. hordei, the suppressing effects of UV-C irradiation on the developmental processes of conidia on artificial surfaces (in vitro) and on host leaf surfaces (in vivo) were assayed. In vitro and in vivo, a single dose of 100 J m-2 UV-C was adequate to decrease conidial germination to < 20 \% and to reduce appressorium formation to values < 5 \%. UV-C irradiation negatively affected colony pustule size and vegetative propagation. Under photoperiodic conditions of 2h light/16h dark, 6h dark/12h light or 6h dark/18h light, UV-C-treated conidia showed photoreactivation (photo-recovery). White light-mediated photoreactivation was most effective immediately after UV-C irradiation, suggesting that a prolonged phase of darkness after UV-C application increased the efficacy of management against B. graminis. UV-C irradiation increased transcript levels of three putative photolyase genes in B. graminis, indicating those were probably involved in photoreactivation processes. However, mere white light or blue light (wavelength peak, 475 nm) could not induce the up-regulation of these genes. To determine whether visible light directly impacted the prepenetration and penetration processes of this powdery mildew pathogen, conidia of Blumeria graminis f. sp. hordei and Blumeria graminis f. sp. tritici were inoculated onto artificial surfaces and on host leaf surfaces. Samples were analyzed after incubation periods under light conditions (white light intensity and spectral quality). Increasing white light intensities directly impaired conidial prepenetration processes in vitro but not in vivo. Applying an agar layer under the wax membrane compensated for conidial water loss as a consequence of high white light irradiation. Light stimulated in vitro and in vivo the appressorium elongation of B. graminis in a wavelength-dependent manner. Red light was more effective to trigger the elongation of appressorium than blue light or green light assayed. Taken together, the findings of this study demonstrate that 1) a host surface recognition principle based on cuticular very-long-chain aldehydes is a common feature of B. graminis f. sp. tritici ascospores and conidia; 2) the transcriptional changes of three putative photolyase genes in B. graminis are mediated in a UV-C-dependent manner; 3) light directly affected the (pre)penetration processes of B. graminis.}, subject = {Blumeria graminis}, language = {en} } @article{EllsaesserRoellAhongshangbametal.2020, author = {Ells{\"a}ßer, Florian and R{\"o}ll, Alexander and Ahongshangbam, Joyson and Waite, Pierre-Andr{\´e} and Hendrayanto, and Schuldt, Bernhard and H{\"o}lscher, Dirk}, title = {Predicting tree sap flux and stomatal conductance from drone-recorded surface temperatures in a mixed agroforestry system — a machine learning approach}, series = {Remote Sensing}, volume = {12}, journal = {Remote Sensing}, number = {24}, issn = {2072-4292}, doi = {10.3390/rs12244070}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220059}, year = {2020}, abstract = {Plant transpiration is a key element in the hydrological cycle. Widely used methods for its assessment comprise sap flux techniques for whole-plant transpiration and porometry for leaf stomatal conductance. Recently emerging approaches based on surface temperatures and a wide range of machine learning techniques offer new possibilities to quantify transpiration. The focus of this study was to predict sap flux and leaf stomatal conductance based on drone-recorded and meteorological data and compare these predictions with in-situ measured transpiration. To build the prediction models, we applied classical statistical approaches and machine learning algorithms. The field work was conducted in an oil palm agroforest in lowland Sumatra. Random forest predictions yielded the highest congruence with measured sap flux (r\(^2\) = 0.87 for trees and r\(^2\) = 0.58 for palms) and confidence intervals for intercept and slope of a Passing-Bablok regression suggest interchangeability of the methods. Differences in model performance are indicated when predicting different tree species. Predictions for stomatal conductance were less congruent for all prediction methods, likely due to spatial and temporal offsets of the measurements. Overall, the applied drone and modelling scheme predicts whole-plant transpiration with high accuracy. We conclude that there is large potential in machine learning approaches for ecological applications such as predicting transpiration.}, language = {en} } @article{FuchsHertelSchuldtetal.2020, author = {Fuchs, Sebastian and Hertel, Dietrich and Schuldt, Bernhard and Leuschner, Christoph}, title = {Effects of summer drought on the fine root system of five broadleaf tree species along a precipitation gradient}, series = {Forests}, volume = {11}, journal = {Forests}, number = {3}, issn = {1999-4907}, doi = {10.3390/f11030289}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203189}, year = {2020}, abstract = {While much research has addressed the aboveground response of trees to climate warming and related water shortage, not much is known about the drought sensitivity of the fine root system, in particular of mature trees. This study investigates the response of topsoil (0-10 cm) fine root biomass (FRB), necromass (FRN), and fine root morphology of five temperate broadleaf tree species (Acer platanoides L., Carpinus betulus L., Fraxinus excelsior L., Quercus petraea (Matt.) Liebl., Tilia cordata Mill.) to a reduction in water availability, combining a precipitation gradient study (nine study sites; mean annual precipitation (MAP): 920-530 mm year\(^{-1}\)) with the comparison of a moist period (average spring conditions) and an exceptionally dry period in the summer of the subsequent year. The extent of the root necromass/biomass (N/B) ratio increase was used as a measure of the species' belowground sensitivity to water deficits. We hypothesized that the N/B ratio increases with long-term (precipitation gradient) and short-term reductions (moist vs. dry period) of water availability, while FRB changes only a little. In four of the five species (exception: A. platanoides), FRB did not change with a reduction in MAP, whereas FRN and N/B ratio increased toward the dry sites under ample water supply (exception: Q. petraea). Q. petraea was also the only species not to reduce root tip frequency after summer drought. Different slopes of the N/B ratio-MAP relation similarly point at a lower belowground drought sensitivity of Q. petraea than of the other species. After summer drought, all species lost the MAP dependence of the N/B ratio. Thus, fine root mortality increased more at the moister than the drier sites, suggesting a generally lower belowground drought sensitivity of the drier stands. We conclude that the five species differ in their belowground drought response. Q. petraea follows the most conservative soil exploration strategy with a generally smaller FRB and more drought-tolerant fine roots, as it maintains relatively constant FRB, FRN, and morphology across spatial and temporal dimensions of soil water deficits.}, language = {en} } @article{VikukFuchsKrischkeetal.2020, author = {Vikuk, Veronika and Fuchs, Benjamin and Krischke, Markus and Mueller, Martin J. and Rueb, Selina and Krauss, Jochen}, title = {Alkaloid Concentrations of Lolium perenne Infected with Epichlo{\"e} festucae var. lolii with Different Detection Methods—A Re-Evaluation of Intoxication Risk in Germany?}, series = {Journal of Fungi}, volume = {6}, journal = {Journal of Fungi}, number = {3}, issn = {2309-608X}, doi = {10.3390/jof6030177}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-213171}, year = {2020}, abstract = {Mycotoxins in agriculturally used plants can cause intoxication in animals and can lead to severe financial losses for farmers. The endophytic fungus Epichlo{\"e} festucae var. lolii living symbiotically within the cool season grass species Lolium perenne can produce vertebrate and invertebrate toxic alkaloids. Hence, an exact quantitation of alkaloid concentrations is essential to determine intoxication risk for animals. Many studies use different methods to detect alkaloid concentrations, which complicates the comparability. In this study, we showed that alkaloid concentrations of individual plants exceeded toxicity thresholds on real world grasslands in Germany, but not on the population level. Alkaloid concentrations on five German grasslands with high alkaloid levels peaked in summer but were also below toxicity thresholds on population level. Furthermore, we showed that alkaloid concentrations follow the same seasonal trend, regardless of whether plant fresh or dry weight was used, in the field and in a common garden study. However, alkaloid concentrations were around three times higher when detected with dry weight. Finally, we showed that alkaloid concentrations can additionally be biased to different alkaloid detection methods. We highlight that toxicity risks should be analyzed using plant dry weight, but concentration trends of fresh weight are reliable.}, language = {en} } @article{OsmanStigloherMuelleretal.2020, author = {Osman, Mohamed and Stigloher, Christian and Mueller, Martin J. and Waller, Frank}, title = {An improved growth medium for enhanced inoculum production of the plant growth-promoting fungus Serendipita indica}, series = {Plant Methods}, volume = {16}, journal = {Plant Methods}, doi = {10.1186/s13007-020-00584-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229186}, year = {2020}, abstract = {Background The plant endophytic fungus Serendipita indica colonizes roots of a wide range of plant species and can enhance growth and stress resistance of these plants. Due to its ease of axenic cultivation and its broad host plant range including the model plant Arabidopsis thaliana and numerous crop plants, it is widely used as a model fungus to study beneficial fungus-root interactions. In addition, it was suggested to be utilized for commercial applications, e.g. to enhance yield in barley and other species. To produce inoculum, S. indica is mostly cultivated in a complex Hill-Kafer medium (CM medium), however, growth in this medium is slow, and yield of chlamydospores, which are often used for plant root inoculation, is relatively low. Results We tested and optimized a simple vegetable juice-based medium for an enhanced yield of fungal inoculum. The described vegetable juice (VJ) medium is based on commercially available vegetable juice and is easy to prepare. VJ medium was superior to the currently used CM medium with respect to biomass production in liquid medium and hyphal growth on agar plates. Using solid VJ medium supplemented with sucrose (VJS), a high amount of chlamydospores developed already after 8 days of cultivation, producing significantly more spores than on CM medium. Use of VJ medium is not restricted to S. indica, as it also supported growth of two pathogenic fungi often used in plant pathology experiments: the ascomycete Fusarium graminearum, the causal agent of Fusarium head blight disease on wheat and barley, and Verticillium longisporum, the causal agent of verticillium wilt. Conclusions The described VJ medium is recommended for streamlined and efficient production of inoculum for the plant endophytic fungus Serendipita indica and might prove superior for the propagation of other fungi for research purposes.}, language = {en} } @article{SchaeblerAmatobiHornetal.2020, author = {Sch{\"a}bler, Stefan and Amatobi, Kelechi M. and Horn, Melanie and Rieger, Dirk and Helfrich‑F{\"o}rster, Charlotte and Mueller, Martin J. and Wegener, Christian and Fekete, Agnes}, title = {Loss of function in the Drosophila clock gene period results in altered intermediary lipid metabolism and increased susceptibility to starvation}, series = {Cellular and Molecular Life Sciences}, volume = {77}, journal = {Cellular and Molecular Life Sciences}, issn = {1420-682X}, doi = {10.1007/s00018-019-03441-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232432}, pages = {4939-4956}, year = {2020}, abstract = {The fruit fly Drosophila is a prime model in circadian research, but still little is known about its circadian regulation of metabolism. Daily rhythmicity in levels of several metabolites has been found, but knowledge about hydrophobic metabolites is limited. We here compared metabolite levels including lipids between period\(^{01}\) (per\(^{01}\)) clock mutants and Canton-S wildtype (WT\(_{CS}\)) flies in an isogenic and non-isogenic background using LC-MS. In the non-isogenic background, metabo-lites with differing levels comprised essential amino acids, kynurenines, pterinates, glycero(phospho)lipids, and fatty acid esters. Notably, detectable diacylglycerols (DAG) and acylcarnitines (AC), involved in lipid metabolism, showed lower levels in per\(^{01}\) mutants. Most of these differences disappeared in the isogenic background, yet the level differences for AC as well as DAG were consistent for fly bodies. AC levels were dependent on the time of day in WTCS in phase with food consumption under LD conditions, while DAGs showed weak daily oscillations. Two short-chain ACs continued to cycle even in constant darkness. per\(^{01}\) mutants in LD showed no or very weak diel AC oscillations out of phase with feeding activity. The low levels of DAGs and ACs in per\(^{01}\) did not correlate with lower total food consumption, body mass or weight. Clock mutant flies showed higher sensitivity to starvation independent of their background-dependent activity level. Our results suggest that neither feeding, energy storage nor mobilisation is significantly affected in per\(^{01}\) mutants, but point towards impaired mitochondrial activity, supported by upregulation of the mitochondrial stress marker 4EBP in the clock mutants}, language = {en} } @article{FukushimaPollock2020, author = {Fukushima, Kenji and Pollock, David D.}, title = {Amalgamated cross-species transcriptomes reveal organ-specific propensity in gene expression evolution}, series = {Nature Communications}, volume = {11,}, journal = {Nature Communications}, doi = {10.1038/s41467-020-18090-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230468}, year = {2020}, abstract = {The origins of multicellular physiology are tied to evolution of gene expression. Genes can shift expression as organisms evolve, but how ancestral expression influences altered descendant expression is not well understood. To examine this, we amalgamate 1,903 RNA-seq datasets from 182 research projects, including 6 organs in 21 vertebrate species. Quality control eliminates project-specific biases, and expression shifts are reconstructed using gene-family-wise phylogenetic Ornstein-Uhlenbeck models. Expression shifts following gene duplication result in more drastic changes in expression properties than shifts without gene duplication. The expression properties are tightly coupled with protein evolutionary rate, depending on whether and how gene duplication occurred. Fluxes in expression patterns among organs are nonrandom, forming modular connections that are reshaped by gene duplication. Thus, if expression shifts, ancestral expression in some organs induces a strong propensity for expression in particular organs in descendants. Regardless of whether the shifts are adaptive or not, this supports a major role for what might be termed preadaptive pathways of gene expression evolution.}, language = {en} }