Person: Heß, Michael
Lade...
E-Mail-Adresse
Geburtsdatum
Forschungsvorhaben
Organisationseinheiten
Berufsbeschreibung
Nachname
Heß
Vorname
Michael
Name
17 Ergebnisse
Suchergebnisse
Gerade angezeigt 1 - 10 von 17
Veröffentlichung Influence of Fusarium avenaceum infections on barley malt: Monitoring changes in the albumin fraction of barley during the malting process(2019) Geißinger, Cajetan; Whitehead, Iain; Heß, Michael; Hofer, KatharinaFusarium spp. are ubiquitous field pathogens, which are known to affect quality characteristics of cereals. Infections with Fusarium pathogens in brewing cereals are problematic and augur for a poor malt quality. The negative effects of Fusarium infections are various. Besides causing agronomic losses, kernel discoloration, and the production of several mycotoxins, Fusarium spp. are known to enhance the proteolytic activity of infected barley malt. Enhanced proteolysis can be observed in higher values in free amino nitrogen (FAN) as well as in soluble nitrogen. Previous studies showed that, in recent crop years, the predominant Fusarium spp. detected in European malt was F. avenaceum. This study focuses on the changes in the albumin fraction during the malting process of barley samples artificially infected with F. avenaceum in comparison to uninfected control samples. The barley samples were grown under controlled conditions in a greenhouse, and two different sample types were studied: One was not infected with Fusarium spores whereas the other sample was inoculated during anthesis with a spore suspension of F. avenaceum. Malting trials were carried out in a micromalting facility under defined conditions. To monitor the changes in protein profiles due to Fusarium infection, samples were analyzed at different stages of the malting process: barley (raw grain), poststeeping, postgermination, and postkilning. To evaluate the changes in the protein composition, different fractionation techniques (Osborne fractionation, isoelectric focusing, and capillary gel electrophoresis) were utilized. The albumins of the Osborne fractionation were further analyzed as they represent the main metabolically active proteins. Protein maps of the different malting steps were plotted with a custom-programmed visualization tool for comparing the infected and uninfected samples at each malting step. The results elucidate the changes in the albumin fraction during the malting process and reveal the influence of Fusarium infection on the albumin composition of barley, barley malt, and the intermediate products of malting. © 2019 Elsevier B.V. All rights reserved.Veröffentlichung Analysis of archive samples of spring and winter barley support an increase in individual Fusarium species in Bavarian barley grain over the last decades(2019) Hofer, Katharina; Heß, Michael; Hückelhoven, RalphA broad range of different Fusarium (F.) species is associated with Fusarium head blight (FHB) on barley and the corresponding negative effects in downstream processing of barley grain in food and feed production. Previous studies highlight the significance of the wheat-relevant and well-studied species F. graminearum as well as less prominent species including F. culmorum, F. avenaceum, F. tricinctum, F. langsethiae, F. sporotrichioides, F. poae, and others. In this context, prevalent climate and cultivation conditions were shown to determine disease severity as well as dominance of certain species within the Fusarium pathogen complex. To gain further insight into possible historic developments of FHB, the annual occurrence of currently relevant Fusarium species was analyzed in Bavarian archive samples of winter (from 1958 to 2010) and spring barley (from 1965 to 2010) using species-specific quantitative polymerase chain reaction. Although DNA contents varied between samples of individual years, data suggest a general increase in Fusarium incidence, particularly in spring barley. Comparing pathogen complexes, we observed not only continuous dominance of F. graminearum in winter barley, but also an increasing relevance of this species in spring barley. The rising Fusarium incidence over time generally coincides with climate change related factors like increasing temperatures. However, it may furthermore be linked to changing cultivation methods and intensified maize production. This study therefore exhibits the dynamic complexity of barley grain contamination with Fusarium spp., which should be taken into account for future disease management. Quelle: https://link.springer.comVeröffentlichung Spore dispersal patterns of the ascomycete fungus Ramularia collo-cygni and their influence on disease epidemics(2023) Havis, N. D.; Kaczmarek, J.; Jedryczka, M.; Heß, Michael; Fang, ZhaolunRamularia leaf spot is a major economic disease of barley caused by the dothidiomycete fungus Ramularia collo-cygni. The fungus has a complex life cycle which includes extensive late season spore release events and a seed-borne phase. Predicting disease epidemics during the growing season remains a difficult challenge. To better understand the interaction between spore movement and disease epidemics, spore samplers were set up in Germany (two sites over 4 years), Poland (seven sites over 2 years) and the UK (two sites over 9 years), where the disease has been observed. Spore concentrations were determined using a real time PCR assay, and meteorological data were obtained from co-located automatic stations. Spore release events were seen to peak in June on mainland Europe and July in the UK. The pattern of spore release was broadly similar across countries with earlier peaks in mainland Europe. A relationship was observed in the UK between July spore levels and disease in following winter barley crops. Rainfall and temperature were proposed as significant drivers of spore release in these months. The major environmental parameter associated with spore release across the two UK sites was crop surface wetness, although some site-specific interactions were noted for rainfall and wind movement. Regression analysis of spore patterns and disease epidemics indicates a relationship between spore levels 75â€Ì105 days pre harvest and final disease levels in UK winter barley crops. This relationship was not observed in spring barley. The implications on risk forecasts are discussed.Veröffentlichung Geht es auch ohne Chemie?(2019) Heß, MichaelDie chemische Saatgutbeize ist das einfachste und sicherste Verfahren. Wenn sie aber nicht mehr wirkt und weiterhin Mittel verloren gehen? Michael Hess diskutiert physikalische und biologische Alternativen. Quelle: https://www.dlg-mitteilungen.deVeröffentlichung The current epidemic of the barley pathogen Ramularia collo-cygni derives from a population expansion and shows global admixture(2019) Stam, Remco; Heß, Michael; Sghyer, Hind; Tellier, AurélienRamularia leaf spot is becoming an ever-increasing problem in main barley-growing regions since the 1980s, causing up to 70% yield loss in extreme cases. Yet, the causal agent Ramularia collo-cygni remains poorly studied. The diversity of the pathogen in the field thus far remains unknown. Furthermore, it is unknown to what extent the pathogen has a sexual reproductive cycle. The teleomorph of R. collo-cygni has not been observed. To study the genetic diversity of R. collo-cygni and get more insights in its biology, we sequenced the genomes of 19 R. collo-cygni isolates from multiple geographic locations and diverse hosts. Nucleotide polymorphism analyses of all isolates shows that R. collo-cygni is genetically diverse worldwide, with little geographic or host specific differentiation. Next, we used two different methods to detect signals of recombination in our sample set. Both methods find putative recombination events, which indicate that sexual reproduction happens or has happened in the global R. collo-cygni population. Lastly, we used these data on recombination to perform historic population size analyses. These suggest that the effective population size of R. collo-cygni decreased during the domestication of barley and subsequently grew with the rise of agriculture. Our findings deepen our understanding of R. collo-cygni biology and can help us to understand the current epidemic. We discuss how our findings support possible global spread through seed transfer, and we highlight how recombination, clonal spreading, and lack of host specificity could amplify global epidemics of this increasingly important disease and suggest specific approaches to combat the pathogen. © 2019 The American Phytopathological SocietyVeröffentlichung Crashkurs Personalentwicklung(Haufe Group, 2020) Grund, Sven; Heß, Michael; Weiss, Wolfgang- Personalentwicklung planen und umsetzen - Schritt-für-Schritt-Anleitungen und zahlreiche Praxisbeispiele - Mit vielen Arbeitshilfen online Gute Maßnahmen zur Personalentwicklung erweitern Wissen und Kompetenzen von Mitarbeitern und binden Leistungsträger langfristig an das Unternehmen. Doch was ist Personalentwicklung überhaupt und welche Rolle nimmt man als "PE-Vertreter" im eigenen Unternehmen ein? Dieser Crashkurs beschreibt Inhalte und Methoden, Herangehensweisen und Instrumente und beantwortet alle wesentlichen Fragen. Sie erhalten ein Prozessmodell, das praxisnah und Schritt für Schritt alle entsprechenden Maßnahmen unterstützt. Neu in der 2. Auflage: Neue, aktualisierte und weiterentwickelte Werkzeuge und Methoden, besonders im Bereich evidenzbasierte Personalentwicklung und Organisationsentwicklung Quelle: VerlagsinformationVeröffentlichung Ramularia leaf spot disease of barley is highly host genotype-dependent and suppressed by continuous drought stress in the field(2021) Hoheneder, Felix; Hofer, Katharina; Heß, Michael; Groth, JenniferSince the 1980s, Ramularia leaf spot (RLS) is an emerging barley disease worldwide. The control of RLS is increasingly aggravated by a recent decline in fungicide efficacy and a lack of RLS-resistant cultivars. Furthermore, climate change increases drought periods in Europe, enhances variable weather conditions, and thus will have an impact on severity of plant diseases. Hence, identification of RLS-resistant cultivars and understanding of disease progression under abiotic stress are important aims in integrated disease management under climate change. In the present study, we evaluated quantitative RLS resistance of 15 spring barley genotypes under drought, controlled irrigation and field conditions between 2016 and 2019 and monitored microclimatic conditions within the canopy. We identified genotypes that show robust quantitative resistance to RLS in different field environments. Our findings suggest that long-lasting drought periods create unfavourable conditions for the disease and supports that the extent and duration of leaf wetness is a key factor for RLS epidemics. © The Author(s) 2021Veröffentlichung Schneeschimmel auch auf Blatt und Ähre!(2019) Heß, MichaelDie Beize bietet nicht immer Schutz: Microdochium-Erreger verursachten in den letzten Jahren immer häufiger Blattsymptome. Und zwar umso häufiger, je besser eine Septoria-Bekämpfung funktioniert hat. Michael Heß erklärt die Zusammenhänge. Quelle: https://www.dlg-mitteilungen.deVeröffentlichung Alternative Maßnahmen gegen Ramularia(2020) Heß, MichaelVeröffentlichung Ramularia nachhaltig bekämpfen durch Erkenntnisse aus der Genom-Analyse(2019) Heß, Michael