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2021

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Sammendrag

Saprolegnia parasitica is recognized as one of the most important oomycetes pests of salmon and trout species. The amplified fragment length polymorphism (AFLP) and method sequence data of the internal transcribed spacer (ITS) were used to study the genetic diversity and relationships of Saprolegnia spp. collected from Canada, Chile, Japan, Norway and Scotland. AFLP analysis of 37 Saprolegnia spp. isolates using six primer combinations gave a total of 163 clear polymorphic bands. Bayesian cluster analysis using genetic similarity divided the isolates into three main groups, suggesting that there are genetic relationships among the isolates. The unweighted pair group method with arithmetic mean (UPGMA) and principal coordinate analysis (PCO) confirmed the pattern of the cluster analyses. ITS analyses of 48 Saprolegnia sequences resulted in five well-defined clades. Analysis of molecular variance (AMOVA) revealed greater variation within countries (91.01%) than among countries (8.99%). We were able to distinguish the Saprolegnia isolates according to their species, ability to produce oogonia with and without long spines on the cysts and their ability to or not to cause mortality in salmonids. AFLP markers and ITS sequencing data obtained in the study, were found to be an efficient tool to characterize the genetic diversity and relationships of Saprolegnia spp. The comparison of AFLP analysis and ITS sequence data using the Mantel test showed a very high and significant correlation (r2 = 0.8317).

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The Norwegian Scientific Committee for Food and Environment (VKM) initiated this work to examine the extent to which organisms developed by genome-editing technologies pose new challenges in terms of risk assessment. This report considers whether the risk assessment guidance on genetically modified organisms, developed by the European Food Safety Authority (EFSA), can be applied to evaluate potential risks of organisms developed by genome editing. Background Gene technology has allowed for the transfer of genes between organisms and species, and thereby to design altered genotypes with novel traits, i.e. GMOs. A new paradigm started in the early 2000s with the development of genome-editing techniques. Unlike traditional genetic modification techniques resulting in insertion of foreign DNA fragments at random locations in the genome, the new genome-editing techniques additionally open for a few single nucleotide edits or short insertions/deletions at a targeted site in an organism’s genome. These new techniques can be applied to most types of organisms, including plants, animals and microorganisms of commercial interest. An important question is how the novel, genome-edited organisms should be evaluated with respect to risks to health and the environment. The European Court of Justice decided in 2018 to include genome-edited organisms in the GMO definition and hence in the regulatory system already in place. This implies that all products developed by genome-editing techniques must be risk-assessed within the existing regulatory framework for GMOs. The European and Norwegian regulatory frameworks regulate the production, import and placing on the market of food and feed containing, consisting of or produced from GMOs, as well as the release of GMOs into the environment. The assessment draws on guidance documents originally developed by EFSA for risk assessment of GMOs, which were drawn up mainly to address risks regarding insertion of transgenes. The new genome-editing techniques, however, provide a new continuum of organisms ranging from those only containing a minor genetic alteration to organisms containing insertion or deletion of larger genomic regions. Risk assessment of organisms developed by genome editing The present discourse on how new genome-editing techniques should be regulated lacks an analysis of whether risk assessment methodologies for GMOs are adequate for risk assessment of organisms developed through the use of the new genome-editing techniques. Therefore, this report describes the use of genome-editing techniques in food and feed production and discusses challenges in risk assessment with the regulatory framework. Specifically, this report poses the question as to whether the EFSA guidance documents are sufficient for evaluating risks to health and environment posed by genome-edited plants, animals and microorganisms. To address these questions, the report makes use of case examples relevant for Norway. These examples, intended for food and feed, include oilseed rape with a modified fatty acid profile, herbicide-tolerant and pest-resistant crops, sterile salmon, virus-resistant pigs and hornless cattle. The report considers all aspects of the stepwise approach as described in the EFSA guidance documents. Conclusions The inherent flexibility of the EFSA guidance makes it suitable to cover health and environmental risk assessments of a wide range of organisms with various traits and intended uses. Combined with the embedded case-by-case approach the guidance is applicable to genome-edited organisms. The evaluation of the guidance demonstrates that the parts of the health and environmental risk assessment concerned with novel traits (i.e. the phenotype of the organism) may be fully applied to all categories of genome-edited organisms. ............

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Sammendrag

A new stubby-root nematode belonging to the Trichodorus sparsus complex was found in association with serious damage to Hill’s Yew hedges (Taxus x media ´Hillii´) in Oslo in 2017, characterised by chlorosis, wilting and loss of needles. T. hellalae n. sp. is about 800 μm long with medium-sized onchiostyle (55 μm, average), characterized in male by two ventromedian cervical papillae located beyond the onchiostyle region and with the secretory excretory pore (SE-pore) in between, in most type specimens, three ventromedian precloacal supplements with the posteriormost one opposite the anterior end of spicule manubrium and spicules 40 μm long (average) with widened manubrium, gradually tapered to a narrower blade without ornamentation of striae or bristles, but showing a minor indentation at level of posterior border of capsule of suspensor muscles. Gubernaculum with thickened keel-like posterior end and a thickened refractive anterior border. Females are characterised by a short pear-shaped vagina, less than 1/3rd of corresponding body width and very small rounded triangular vaginal sclerotized pieces in longitudinal optical section and vulva pore-like in ventral view; on each body side one sublateral body pore at about 3.5 body width anterior to vulva and one postadvulvar body pore. According to D2-D3 analyses, the Trichodorus hellalae n. sp. sequences are embedded in a maximally supported clade with several T. variabilis lineages. However, morphological and molecular species delimitation both support Trichodorus hellalae n. sp. as being a new species. Therefore, T. variabilis now appears to in fact consists of several cryptic species.