Dynamic Evolution of Pathogenicity Revealed by Sequencing and Comparative Genomics of 19 Pseudomonas syringae Isolates

Closely related pathogens may differ dramatically in host range, but the molecular, genetic, and evolutionary basis for these differences remains unclear. In many Gram- negative bacteria, including the phytopathogen Pseudomonas syringae, type III effectors (TTEs) are essential for pathogenicity, instrumental in structuring host range, and exhibit wide diversity between strains. To capture the dynamic nature of virulence gene repertoires across P. syringae, we screened 11 diverse strains for novel TTE families and coupled this nearly saturating screen with the sequencing and assembly of 14 phylogenetically diverse isolates from a broad collection of diseased host plants. TTE repertoires vary dramatically in size and content across all P. syringae clades; surprisingly few TTEs are conserved and present in all strains. Those that are likely provide basal requirements for pathogenicity. We demonstrate that functional divergence within one conserved locus, hopM1, leads to dramatic differences in pathogenicity, and we demonstrate that phylogenetics-informed mutagenesis can be used to identify functionally critical residues of TTEs. The dynamism of the TTE repertoire is mirrored by diversity in pathways affecting the synthesis of secreted phytotoxins, highlighting the likely role of both types of virulence factors in determination of host range. We used these 14 draft genome sequences, plus five additional genome sequences previously reported, to identify the core genome for P. syringae and we compared this core to that of two closely related non-pathogenic pseudomonad species. These data revealed the recent acquisition of a 1 Mb megaplasmid by a sub-clade of cucumber pathogens. This megaplasmid encodes a type IV secretion system and a diverse set of unknown proteins, which dramatically increases both the genomic content of these strains and the pan-genome of the species

Strategisches Asset-Liability Management in der Versicherungswirtschaft – Ein Ansatz zur integrierten Bilanzstrukturoptimierung

Asset-Liability Management gewinnt in der deutschen Versicherungswirtschaft zunehmend an Bedeutung. Dies ist zum einen den Entwicklungen auf den Kapitalmärken in den vergangenen Jahren geschuldet, die es Versicherern erschweren, gegebene Zinsgarantien zu erwirtschaften. Zum anderen erwachsen aus dem sich maßgeblich verändernden Regulierungsrahmen neue Anforderungen für das ALM. Solvency II wird einen Paradigmenwechsel zu einer vorwiegend ökonomischen Bertachtungsweise der Versicherungsbilanzen, insbesondere der Passiva erfordern. Herkömmliche ALM-Instrumente werden diesen neuen Anforderungen selten gerecht, weil sie die Positionen auf beiden Bilanzseiten unter risikotheoretischen Aspekten nicht simultan optimieren. In diesem Artikel wird integrierter Ansatz zur Optimierung der Bilanzstruktur in Lebensversicherungsunternehmen beschrieben, der sich der Markowitzschen Portfolio Selection bedient. Dabei werden die neuen aufsichtsrechtlichen Erfordernisse mit der modernen Kapitalmarkttheorie verbunden und so ein Instrument zu einer integrierten, strategischen Steuerung der Kapitalanlagepolitik von Versicherungsunternehmen geschaffen

The complete genome sequence of the Arabidopsis and tomato pathogen Pseudomonas syringae pv. tomato DC3000

We report the complete genome sequence of the model bacterial pathogen Pseudomonas syringae pathovar tomato DC3000 (DC3000), which is pathogenic on tomato and Arabidopsis thaliana. The DC3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 ORFs. We identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type III secretion system effector proteins. Many of the virulence genes were members of paralogous families and also were proximal to mobile elements, which collectively comprise 7% of the DC3000 genome. The bacterium possesses a large repertoire of transporters for the acquisition of nutrients, particularly sugars, as well as genes implicated in attachment to plant surfaces. Over 12% of the genes are dedicated to regulation, which may reflect the need for rapid adaptation to the diverse environments encountered during epiphytic growth and pathogenesis. Comparative analyses confirmed a high degree of similarity with two sequenced pseudomonads, Pseudomonas putida and Pseudomonas aeruginosa, yet revealed 1,159 genes unique to DC3000, of which 811 lack a known function