Eindämmung des Erregers der Anthraknose der Lupine im ökologischen Landbau durch Anbau weniger anfälliger Lupinensorten der drei landwirtschaftlich wichtigen Lupinenarten

Das Projekt befasste sich mit einem Sortenscreening von 23 Lupinus albus-, 14 L. luteus- und 21 L. angustifolius-Sorten auf die Reaktion gegenüber einer Infektion mit Colletotrichum lupini var. setosum. Für die Infektion der Samen wurde der Substrattest, eine Methode, die die Primärinfektion des Pathogens simuliert, genutzt. Der Einfluß der Infektion auf verschiedene Merkmale, wie Überlebensrate der Pflanzen, Symptome, Befallsverlauf und auf den Ertrag wurden bewertet. Die drei Lupinenarten zeigten unterschiedliche Krankheitssymptome. Während die Symptome bei L. luteus und L.angustifolius oft untypisch waren, entwickelten sich bei L. albus bekanntere Anthraknosesymptome. Unterschiedliche Verhaltensweisen der drei Lupinenarten waren auch im Befallsverlauf zu finden. Die Versuche lieferten interessante Ergebnisse zum Verhalten der einzelnen Lupinenarten und -sorten gegenüber der Infektion mit dem Anthraknoseerreger. Die höchste Absterberate der Pflanzen aller 3 Lupinenarten war während des Keimlings- und Jungpflanzenstadiums. Der Entwicklungsverlauf der Mykose und die Symptomausprägung waren jedoch bei den Lupinenarten unterschiedlich. Die Überlebensrate der Pflanzen war stark abhängig von der jeweiligen Sorte. Die Ergebnisse sind eine fundierte Materialgrundlage zur Krankheit Anthraknose. Die Sortenunterschiede lassen ein erhebliches Toleranzpotential gegenüber dem Pilz Colletotrichum lupini var. setosum erkennen, so daß entsrechend unterschiedlicher Fragestellungen Sorten anhand der Projektergebnisse auswählt werden können

Constructing solutions to the Bj\"orling problem for isothermic surfaces by structure preserving discretization

In this article, we study an analog of the Bj\"orling problem for isothermic surfaces (that are more general than minimal surfaces): given a real analytic curve $\gamma$ in ${\mathbb R}^3$, and two analytic non-vanishing orthogonal vector fields $v$ and $w$ along $\gamma$, find an isothermic surface that is tangent to $\gamma$ and that has $v$ and $w$ as principal directions of curvature. We prove that solutions to that problem can be obtained by constructing a family of discrete isothermic surfaces (in the sense of Bobenko and Pinkall) from data that is sampled along $\gamma$, and passing to the limit of vanishing mesh size. The proof relies on a rephrasing of the Gauss-Codazzi-system as analytic Cauchy problem and an in-depth-analysis of its discretization which is induced from the geometry of discrete isothermic surfaces. The discrete-to-continuous limit is carried out for the Christoffel and the Darboux transformations as well.Comment: 29 pages, some figure

Biodiversity of Fusarium species in Mexico associated with ear rot in maize, and their identification using a phylogenetic approach

Fusariumproliferatum, F. subglutinans, and F. verticillioides are known causes of ear and kernel rot in maize worldwide. In Mexico, only F. verticillioides and F. subglutinans, have been reported previously as causal agents of this disease. However, Fusarium isolates with different morphological characteristics to the species that are known to cause this disease were obtained in the Highland-Valley region of this country from symptomatic and symptomless ears of native and commercial maize genotypes. Moreover, while the morphological studies were not sufficient to identify the correct taxonomic position at the species level, analyses based in the Internal Transcribed Spacer region and the Nuclear Large Subunit Ribosomal partial sequences allowed for the identification of F. subglutinans, F. solani, and F. verticillioides, as well as four species (F. chlamydosporum, F. napiforme, F. poae, and F. pseudonygamai) that had not previously been reported to be associated with ear rot. In addition, F. napiforme and F. solani were absent from symptomless kernels. Phylogenetic analysis showed genetic changes in F. napiforme, and F. pseudonygamai isolates because they were not true clones, and probably constitute separate sibling species. The results of this study suggest that the biodiversity of Fusarium species involved in ear rot in Mexico is greater than that reported previously in other places in the world. This new knowledge will permit a better understanding of the relationship between all the species involved in ear rot disease and their relationship with maize

Gene family expansions and contractions are associated with host range in plant pathogens of the genus Colletotrichum

Background: Many species belonging to the genus Colletotrichum cause anthracnose disease on a wide range of plant species. In addition to their economic impact, the genus Colletotrichum is a useful model for the study of the evolution of host specificity, speciation and reproductive behaviors. Genome projects of Colletotrichum species have already opened a new era for studying the evolution of pathogenesis in fungi. Results: We sequenced and annotated the genomes of four strains in the Colletotrichum acutatum species complex (CAsc), a clade of broad host range pathogens within the genus. The four CAsc proteomes and secretomes along with those representing an additional 13 species (six Colletotrichum spp. and seven other Sordariomycetes) were classified into protein families using a variety of tools. Hierarchical clustering of gene family and functional domain assignments, and phylogenetic analyses revealed lineage specific losses of carbohydrate-active enzymes (CAZymes) and proteases encoding genes in Colletotrichum species that have narrow host range as well as duplications of these families in the CAsc. We also found a lineage specific expansion of necrosis and ethylene-inducing peptide 1 (Nep1)-like protein (NLPs) families within the CAsc. Conclusions: This study illustrates the plasticity of Colletotrichum genomes, and shows that major changes in host range are associated with relatively recent changes in gene content

Neuroarchitecture of Aminergic Systems in the Larval Ventral Ganglion of Drosophila melanogaster

Biogenic amines are important signaling molecules in the central nervous system of both vertebrates and invertebrates. In the fruit fly Drosophila melanogaster, biogenic amines take part in the regulation of various vital physiological processes such as feeding, learning/memory, locomotion, sexual behavior, and sleep/arousal. Consequently, several morphological studies have analyzed the distribution of aminergic neurons in the CNS. Previous descriptions, however, did not determine the exact spatial location of aminergic neurite arborizations within the neuropil. The release sites and pre-/postsynaptic compartments of aminergic neurons also remained largely unidentified. We here used gal4-driven marker gene expression and immunocytochemistry to map presumed serotonergic (5-HT), dopaminergic, and tyraminergic/octopaminergic neurons in the thoracic and abdominal neuromeres of the Drosophila larval ventral ganglion relying on Fasciclin2-immunoreactive tracts as three-dimensional landmarks. With tyrosine hydroxylase- (TH) or tyrosine decarboxylase 2 (TDC2)-specific gal4-drivers, we also analyzed the distribution of ectopically expressed neuronal compartment markers in presumptive dopaminergic TH and tyraminergic/octopaminergic TDC2 neurons, respectively. Our results suggest that thoracic and abdominal 5-HT and TH neurons are exclusively interneurons whereas most TDC2 neurons are efferent. 5-HT and TH neurons are ideally positioned to integrate sensory information and to modulate neuronal transmission within the ventral ganglion, while most TDC2 neurons appear to act peripherally. In contrast to 5-HT neurons, TH and TDC2 neurons each comprise morphologically different neuron subsets with separated in- and output compartments in specific neuropil regions. The three-dimensional mapping of aminergic neurons now facilitates the identification of neuronal network contacts and co-localized signaling molecules, as exemplified for DOPA decarboxylase-synthesizing neurons that co-express crustacean cardioactive peptide and myoinhibiting peptides

Eindämmung des Erregers der Anthraknose der Lupine im ökologischen Landbau durch Anbau weniger anfälliger Lupinensorten der drei landwirtschaftlich wichtigen Lupinenarten

Das Projekt befasste sich mit einem Sortenscreening von 23 Lupinus albus-, 14 L. luteus- und 21 L. angustifolius-Sorten auf die Reaktion gegenüber einer Infektion mit Colletotrichum lupini var. setosum. Für die Infektion der Samen wurde der Substrattest, eine Methode, die die Primärinfektion des Pathogens simuliert, genutzt. Der Einfluß der Infektion auf verschiedene Merkmale, wie Überlebensrate der Pflanzen, Symptome, Befallsverlauf und auf den Ertrag wurden bewertet. Die drei Lupinenarten zeigten unterschiedliche Krankheitssymptome. Während die Symptome bei L. luteus und L.angustifolius oft untypisch waren, entwickelten sich bei L. albus bekanntere Anthraknosesymptome. Unterschiedliche Verhaltensweisen der drei Lupinenarten waren auch im Befallsverlauf zu finden. Die Versuche lieferten interessante Ergebnisse zum Verhalten der einzelnen Lupinenarten und -sorten gegenüber der Infektion mit dem Anthraknoseerreger. Die höchste Absterberate der Pflanzen aller 3 Lupinenarten war während des Keimlings- und Jungpflanzenstadiums. Der Entwicklungsverlauf der Mykose und die Symptomausprägung waren jedoch bei den Lupinenarten unterschiedlich. Die Überlebensrate der Pflanzen war stark abhängig von der jeweiligen Sorte. Die Ergebnisse sind eine fundierte Materialgrundlage zur Krankheit Anthraknose. Die Sortenunterschiede lassen ein erhebliches Toleranzpotential gegenüber dem Pilz Colletotrichum lupini var. setosum erkennen, so daß entsrechend unterschiedlicher Fragestellungen Sorten anhand der Projektergebnisse auswählt werden können