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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2024

Abstract

Erwinia amylovora, the causative agent of fire blight of pome fruits and other rosaceous plants belongs to the group of regulated quarantine pests. The aim of this work was to characterize the populations of E. amylovora in Norway and their geographical distribution. A total of 238 E. amylovora isolates recovered from symptomatic host plants in Norway between 1986 and 2004 were genotyped by means of a short sequence repeat (SSR) marker (ATTACAGA) on plasmid pEa29. The SSR region was amplified and amplicon size determined using fluorescent labelling and rapid, automated capillary gel electrophoresis. All isolates contained the pEa29 plasmid harbouring the investigated marker. In total, ten genotypes were identified, of which two were detected only once. The number of repeats varied from 3 to 13, with 43% of the isolates containing five repeats. Of 17 isolates collected between 1986 and 1991, all but one contained five repeats, whereas more variation was observed in isolates from the period 2000 to 2004. Most of the isolates (80%) originated from Cotoneaster bullatus, hence no relationship between genotype of the isolate and host species that it was isolated from could be detected. This historic data suggests multiple introductions of E. amylovora to Norway.

Abstract

During the cultivation of Ulva fenestrata in a land-based aquaculture system, the colonisation of the water tanks’ surfaces and eventually the macroalgal biomass by the biofouling diatom Fragilariopsis oceanica compromises the production process. Since germanium dioxide (GeO2) is an effective growth inhibitor of diatoms, this study aimed to understand how it affects the presence of F. oceanica and the photosynthesis and growth of U. fenestrata as a primary parameter contribution to the biomass production. A toxicological dose-response experiment showed that the diatom’s growth was inhibited at the low GeO2 concentration of 0.014 mg l−1. In contrast, the photosynthetic performances and growth rates of U. fenestrata remained unaffected under a wide GeO2 concentration range (0.022–2.235 mg l−1) in small- and large-scale experiments in 1-l glass beakers and 100-l Plexiglass water tanks, respectively. In the latter, the diatom density in the tanks was reduced by 40 %. The costs arising from the use of GeO2 can range between €2.35 and €8.35  kg−1 fresh weight of produced U. fenestrata biomass under growth conditions resulting in growth rates of 20 and 11.5 % d−1, respectively. GeO2 is an effective agent to control biofouling diatoms such as F. oceanica during the land-based biomass production of U. fenestrata.