Genetic analysis of signalling components of PAMP-triggered immunity (PTI) in plants

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

How to facilitate a global open science early-career research community with local impact

2018/19 eLife Ambassadors progra

Effective data management to promote reproducibility

2018/19 eLife Ambassadors progra

Foto/Lyrik: Faktualität und Fiktionalität in der intermedialen Kombination lyrischer Texte und fotografischer Bilder in der Gegenwart

Diese Arbeit widmet sich den Möglichkeiten und Bedingungen von Faktualität und Fiktionalität in der intermedialen Kombination lyrischer Texte und fotografischer Bilder in ausgewählten Werken der Gegenwart von Angela Krauß, Barbara Köhler und Thomas Kling. Im ersten Teil der Arbeit werden aus einer theoretischen Perspektive aktuelle Ansätze aus der Lyrik- und Fotografietheorie mit aktuellen Ansätzen aus der Fiktionalitäts- und Faktualitätstheorie verglichen und so die allgemeinen gattungs- und medienspezifischen Möglichkeiten und Bedingungen der Fiktionalität und Faktualität lyrischer Texte und fotografischer Bilder untersucht. In der Analyse der ausgewählten foto-lyrischen Arbeiten, Angela Krauß` 'Eine Wiege', Barbara Köhlers 'Istanbul, zusehends' und Thomas Klings 'aufnahme mai 1914', sowie denen in Kooperation mit Ute Langanky entstandenen 'mahlbezirk' und 'beowulf spricht', werden die zuvor theoretisch herausgearbeiteten Möglichkeiten und Bedingungen der Faktualität und Fiktionalität lyrischer Texte und fotografischer Bilder in der Analyse herausragender Arbeiten der Gegenwartslyrik an konkreten Beispielen untersucht. Während sich der theoretische Teil der Arbeit in die aktuelle Fiktionalitäts- und Faktualitätstheorie, sowie Lyrik- und Fotografietheorie einordnet, und etwa als Ausgangspunkt für weiterführende Untersuchungen der medien- und gattungsspezifischen Möglichkeiten und Bedingungen von Fiktionalität und Faktualität dienen kann, werden im analytischen Teil der Arbeit ausgewählte foto-lyrische Werke der Gegenwart einer detaillierten Analyse unterzogen. Diese können wiederum als Grundlage für die Untersuchung weiterer foto-lyrischer Arbeiten dienen und ermöglichen einen historischen wie kulturellen Vergleich mit anderen Arbeiten

Fundamental wheat stripe rust research in the 21st century

In the 21st century, the wheat stripe rust fungus has evolved to be the largest biotic limitation to global wheat production. New pathogen genotypes are more aggressive and able to infect previously resistant wheat varieties, leading to rapid pathogen migration across and between continents. We now know the full life cycle, microevolutionary relationships and past migration routes on a global scale. Current sequencing technologies have provided the first fungal draft genomes and simplified plant resistance gene cloning. Yet, we know nothing about the molecular and microevolutionary mechanisms that facilitate the infection process and cause new devastating pathogen races. These are the questions that need to be addressed by exploiting the synergies between novel 21st century biology tools and decades of dedicated pathology workI am supported by an Australian Research Council Discovery Early Career Research Award (DE150101897)

Transposon-Mediated Horizontal Transfer of the Host-Specific Virulence Protein ToxA between Three Fungal Wheat Pathogens

Most known examples of horizontal gene transfer (HGT) between eukaryotes are ancient. These events are identified primarily using phylogenetic methods on coding regions alone. Only rarely are there examples of HGT where noncoding DNA is also reported. The gene encoding the wheat virulence protein ToxA and the surrounding 14 kb is one of these rare examples. ToxA has been horizontally transferred between three fungal wheat pathogens (Parastagonospora nodorum, Pyrenophora tritici-repentis, and Bipolaris sorokiniana) as part of a conserved ∼14 kb element which contains coding and noncoding regions. Here we used long-read sequencing to define the extent of HGT between these three fungal species. Construction of near-chromosomal-level assemblies enabled identification of terminal inverted repeats on either end of the 14 kb region, typical of a type II DNA transposon. This is the first description of ToxA with complete transposon features, which we call ToxhAT. In all three species, ToxhAT resides in a large (140-to-250 kb) transposon-rich genomic island which is absent in isolates that do not carry the gene (annotated here as toxa−). We demonstrate that the horizontal transfer of ToxhAT between P. tritici-repentis and P. nodorum occurred as part of a large (∼80 kb) HGT which is now undergoing extensive decay. In B. sorokiniana, in contrast, ToxhAT and its resident genomic island are mobile within the genome. Together, these data provide insight into the noncoding regions that facilitate HGT between eukaryotes and into the genomic processes which mask the extent of HGT between these species.M.C.M. acknowledges The Sun Foundation’s Peer Prize for Women in Science for support to sequence additional ToxA isolates. E.H. acknowledges The Grains and Research Development Corporation (project UHS11002). M.C.M., A.M., S.S., and P.S.S. also acknowledge The Grains and Research Development Corporation for the collection of isolates (projects DAN00203 and DAN00177)

Variation and inheritance of the Xanthomonas raxX-raxSTAB gene cluster required for activation of XA21-mediated immunity

The rice XA21-mediated immune response is activated on recog-nition of the RaxX peptide produced by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). The 60-residue RaxX pre-cursor is post-translationally modified to form a sulfated tyrosine peptide that shares sequence and functional similarity with the plant sulfated tyrosine (PSY) peptide hormones. The 5-kb raxX-raxSTAB gene cluster of Xoo encodes RaxX, the RaxST tyrosyl-protein sulfotransferase, and the RaxA and RaxB components of a predicted type I secretion system. To assess raxX-raxSTAB gene cluster evolution and to determine its phylogenetic distribution, we first identified rax gene homologues in other genomes. We detected the complete raxX-raxSTAB gene cluster only in Xanthomonas spp., in five distinct lineages in addition to X.ory-zae. The phylogenetic distribution of the raxX-raxSTAB gene cluster is consistent with the occurrence of multiple lateral (hori-zontal) gene transfer events during Xanthomonas speciation. RaxX natural variants contain a restricted set of missense substi-tutions, as expected if selection acts to maintain peptide hor-mone-like function. Indeed, eight RaxX variants tested all failed to activate the XA21-mediated immune response, yet retained peptide hormone activity. Together, these observations support the hypothesis that the XA21 receptor evolved specifically to rec-ognize Xoo RaxX.This study was supported by Public Health Service research grants GM059962 and GM122968 from the National Institute of General Medical Sciences awarded to P.C.R