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.
2017
Authors
Shuxin Han Yanling Gao Guoquan Fan Wei Zhang Cailing Qiu Shu Zhang Yanju Bai Junhua Zhang Carl Jonas Jorge SpetzAbstract
This study reports the findings of a distinct Potato virus Y (PVY) isolate found in Northeast China. One hundred and ten samples (leaves and tubers) were collected from potato plants showing mosaic symptoms around the city of Harbin in Heilongjiang province of China. The collected tubers were planted and let to grow in a greenhouse. New potato plants generated from these tubers showed similar symptoms, except for one plant. Subsequent serological analyses revealed PVY as the causing agent of the disease. A novel PVY isolate (referred to as HLJ-C-44 in this study) was isolated from this sample showing unique mild mosaic and crisped leaf margin symptoms. The complete genome of this isolate was analyzed and determined. The results showed that HLJ-C-44 is a typical PVY isolate. Phylogenetic analysis indicated that this isolate belongs to the N-Wi strain group of PVY recombinants (PVYN-Wi) and also shared the highest overall sequence identity (nucleotide and amino acid) with other members of this strain group. However, recombination analysis of isolate HLJ-C-44 revealed a recombination pattern that differed from that of other PVYN-Wi isolates. Moreover, biological assays in four different potato cultivars and in Nicotiana tabacum also revealed a different phenotypic response than that of a typical PVYN-Wi isolate. This data, combined, suggest that HLJ-C-44 is a novel PVY recombinant with distinct biological properties.
Abstract
No abstract has been registered
Abstract
The extractive content of inner and outer heartwood of nine Scots pine trees from three different stands in Norway was determined by automated solvent extraction and biological screening tests were performed using basidiomycetes. The evaluation of mass spectra by means of a NIST library search shows that in the petroleum ether extracts α-pinene and carene as well as terpinene and cadinene derivatives are the main extractives found in both inner and outer heartwood. In the inner heartwood, however, these substance groups were found in lower quantities. These substances mainly have a hydrophobic effect. The screening tests indicate that also extractive-rich heartwood is extremely degraded by Poria placenta which corresponds to the analytical results of the petroleum ether extracts.
Abstract
No abstract has been registered
Academic – A study of variance estimation methods for systematic spatial sampling
Geir-Harald Strand
Authors
Geir-Harald StrandAbstract
An undesirable property of systematic spatial sampling is that there is no known method allowing unbiased estimation of the uncertainty of statistical estimates from these surveys. A number of alternative variance estimation methods have been tested and reported by various authors. Studies comparing these estimators are inconclusive, partly because the studies compare different sets of estimators. In this paper, three estimators recommended in recent studies are compared using a single test dataset with known properties. The first estimator compared in this study (ST4) is based on post-stratification of the data. The second estimator (V08) is using a predetermined correction factor calculated from the spatial autocorrelation. The third estimator (MB) is a model based prediction calculated using values from the semivariogram. MB and ST4 were both found to be fairly accurate, while V08 consistently underestimated the variance in this study. V08 relies on the assumption that the autocorrelation structure in the dataset can be described using a particular exponential function. The most likely explanation of the weak result for V08 is that this assumption is violated by the empirical data used in the experiment. A better correction factor can be calculated, but the safe approach is to use MB or ST4.
Authors
Frans-Jan W. Parmentier Torben R. Christensen Søren Rysgaard Jørgen Bendtsen Ronnie N. Glud Brent Else Jacobus van Huissteden Torsten Sachs Jorien E. Vonk Mikael K. SejrAbstract
The current downturn of the arctic cryosphere, such as the strong loss of sea ice, melting of ice sheets and glaciers, and permafrost thaw, affects the marine and terrestrial carbon cycles in numerous interconnected ways. Nonetheless, processes in the ocean and on land have been too often considered in isolation while it has become increasingly clear that the two environments are strongly connected: Sea ice decline is one of the main causes of the rapid warming of the Arctic, and the flow of carbon from rivers into the Arctic Ocean affects marine processes and the air–sea exchange of CO2. This review, therefore, provides an overview of the current state of knowledge of the arctic terrestrial and marine carbon cycle, connections in between, and how this complex system is affected by climate change and a declining cryosphere. Ultimately, better knowledge of biogeochemical processes combined with improved model representations of ocean–land interactions are essential to accurately predict the development of arctic ecosystems and associated climate feedbacks.
Abstract
Helminthosporium solani causes silver scurf, which affects the quality of potato. The biocontrol agent Clonostachys rosea greatly limited the severity of silver scurf symptoms and amount of H. solani genomic DNA in laboratory experiments. Transcriptomic analysis during interaction showed that H. solani gene expression was highly reduced when coinoculated with the biocontrol agent C. rosea, whereas gene expression of C. rosea was clearly boosted as a response to the pathogen. The most notable upregulated C. rosea genes were those encoding proteins involved in cellular response to oxidative stress, proteases, G-protein signaling, and the methyltransferase LaeA. The most notable potato response to both fungi was downregulation of defense-related genes and mitogen-activated protein kinase kinase kinases. At a later stage, this shifted, and most potato defense genes were turned on, especially those involved in terpenoid biosynthesis when H. solani was present. Some biocontrol-activated defense-related genes in potato were upregulated during early interaction with C. rosea alone that were not triggered by H. solani alone. Our results indicate that the reductions of silver scurf using C. rosea are probably due to a combination of mechanisms, including mycoparasitism, biocontrol-activated stimulation of plant defense mechanisms, microbial competition for nutrients, space, and antibiosis.
Authors
Wagma Saei Rasmus Dam Wollenberg Klaus Ringsborg Westphal Erik Lysøe Donald Max Gardiner Reinhard Wimmer Teis Esben Sondergaard Jens Laurids SørensenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Laurens Klerkx Egil Petter Stræte Gunn-Turid Kvam Eystein Ystad Renate Marie Butli HårstadAbstract
No abstract has been registered