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The objective of this study was to develop a rapid, sensitive detection assay for the quarantine pathogen Xanthomonas arboricola pv. pruni, causal agent of stone fruit bacterial spot, an economically important disease of Prunus spp. Unique targets were identified from X. arboricola pv. pruni genomes using a comparative genomics pipeline of other Xanthomonas species, subspecies and pathovars, and used to identify specific diagnostic markers. Loop-mediated isothermal amplification (LAMP) was then applied to these markers to provide rapid, sensitive and specific detection. The method developed showed unrivalled specificity with the 79 tested strains and, in contrast to previously established techniques, distinguished between phylogenetically close subspecies such as X. arboricola pv. corylina. The sensitivity of this test is comparable to that of a previously reported TaqMan™ assay at 103 CFU mL−1, while the unrivalled speed of LAMP technology enables a positive result to be obtained in

SummaryThis study aimed to assess the genetic diversity present among Swiss cherry accessions using the microsatellite markers (SSRs) proposed by the Prunus working group of the ECPGR-FN (European Collaborative Programme for Genetic Resources-Fruit Network) for varietal identification. We analysed 567 cherry accessions from nationwide collections of the fruit genetic resources inventory, and from the nuclear stock of Agroscope ACW, an archive of healthy, virus-free fruit varieties. Of the 20 SSRs tested, 14 resulted in polymorphic and useful multiplex mixes covering the entire cherry genome. The numbers of alleles per locus ranged from two to 21, which was generally higher than reported in the literature. Several groups of putative synonyms, with up to 16 accessions, were found, reducing the number of individual genetic profiles to 278. This represents a 49% reduction of the total number of genetically different accessions. Our results may therefore lead to making the maintenace of, and breeding from, Swi...

1. Die normale Entwicklung der Meduse vonPodocoryne carnea M.Sars wird aufgrund morphologischer und anatomischer Kriterien in insgesamt 10 Differenzierungsstadien unterteilt. 2. Medusenknospen, die fruhzeitig vom Blastostyl isoliert werden, sind lebensfahig und vollbringen verschiedene Entwicklungsleistungen, deren Art und Haufigkeit vom Entwicklungsalter der Knospe im Moment der Isolation abhangig sind. 3. Junge Medusenknospen der Stadien 1–4 sind nach Isolation einem Dedifferenzierungsprozes unterworfen, der zu einem sog. „Kugelstadium“ fuhrt. Aus diesem morphogenetisch indifferenten Stadium konnen Stolonen und aus diesen wiederum Nahrpolypen entstehen. Dieser von jungen Medusenknospen ausgehende Strukturwandel kann als Metaplasie bezeichnet werden. 4. Altere, in den Stadien 5–8 isolierte Medusenknospen entwickeln sich in der Regel zu Medusen oder medusenahnlichen Gebilden weiter. Der kritische Zeitpunkt, in welchem die Entwicklungsrichtung der Meduse irreversibel festgelegt wird und von dem aus die Differenzierung der Meduse autonom erfolgen kann, liegt zwischen den Entwicklungsstadien 4 und 5. 5. Zellreaggregate, die durch Dissoziation voll ausdifferenzierter Medusen gewonnen wurden, bildeten in wenigen Fallen Stolonen und stolonenahnliche Gebilde. Dies bedeutet, das wenigstens ein Teil der die Meduse aufbauenden Zellen die Fahigkeit zur funktionellen und strukturellen Metaplasie nicht irreversibel verloren hat. 6. Samtliche im Verlaufe dieser Untersuchungen beobachteten Strukturwandlungen fuhrten uber den als niedrigste Realisationsstufe zu bezeichnenden Zustand des Stolo, aus dem unter gunstigen Voraussetzungen die nachsthoheren Stufen (Frespolypen, Blastostyle) hervorgehen konnen.

1. The normal development of medusa ofPodocoryne carnea M.SARS is divided into 10 different stages according to morphological and anatomical criteria. 2. Medusa buds are viable and develop different patterns of differentiation when isolated early from the blastostyl. These patterns depend on type and frequency of the bud's age of development at the moment of isolation. 3. After isolation young medusa buds of the stages 1-4 are submitted to a process of dedifferentiation leading to a "Kugelstadium" (two-layered sphere). Out of this morphogenetically indifferent stage stolos can emerge. These often give rise to gasterozooids. This structural change, originating from young medusa buds, may be termed metaplasia. 4. Older medusa buds isolated in the stages 5-8 develop normally into medusae or medusa-like structures. The critical phase when the direction of development of the medusa is irreversibly fixed and out of which the differentiation of the medusa can autonomically emerge, lies between the bud-stages 4 and 5. 5. Aggregates of cells, obtained by dissociation of fully differenciated medusae, in a few cases produced stolos and structures of stolo-like shape. This means that at least part of the medusa cells has not irreversibly lost the ability to functional and structural metaplasia. 6. All the changes of structure, observed in the course of the investigations, led to a stolo to be designated as the most primitive stage of differentiation. Under favourable conditions the next higher stages (gasterozooids, blastostyls) can emerge.