Knud Nor Nielsen

• Doctor of Philosophy
• PhD Student at University of Copenhagen

Some introduced populations thrive and evolve despite the presumed loss of diversity at introduction. We aimed to quantify the amount of genetic diversity retained at introduction in species that have shown evidence of adaptation to their introduced environments. Samples were taken from native and introduced ranges of Arctotheca populifolia and Pet...

The study describes the primary assembly of arbuscular mycorrhizal communities on a newly constructed island Peberholm between Denmark and Sweden. The AM fungal community on Peberholm was compared with the neighboring natural island Saltholm. The structure of arbuscular mycorrhizal communities was assessed through 454 pyrosequencing. Internal commu...

The epidemic outbreak in northern Europe of Neonectria neomacrospora, the causal agent of dieback in Abies spp., led the European and Mediterranean Plant Protection Organization (EPPO) to include the pathogen on its alert list in 2017. Effective monitoring of this pathogen calls for a rapid and sensitive method of identification and quantification....

The fungal plant pathogen Neonectria neomacrospora (C. Booth & Samuels) Mantiri & Samuels (Ascomycota, Hypocreales) is a bark parasite causing twig blight, canker, and in severe cases, dieback in fir ( Abies spp.). Although often described as a mild pathogen, foresty and phytosanitary agencies have expressed their concern for potential economic imp...

The fungal pathogen Neonectria neomacrospora is of increasing concern in Europe where, within the last decade, it has caused substantial damage to forest stands and ornamental trees of the genus Abies (Mill.). Using whole-genome sequencing of a comprehensive collection of isolates, we show the extent of three major clades within N. neomacrospora ,...

A common procedure for studying the microbiome is binning the sequenced contigs into metagenome-assembled genomes. Currently, unsupervised and self-supervised deep learning based methods using co-abundance and sequence based motifs such as tetranucleotide frequencies are state-of-the-art for metagenome binning. Taxonomic labels derived from alignme...

Host manipulation by pathogens and parasites is a widespread phenomenon, but the molecular mechanisms are poorly understood. We investigated the summiting disease caused by the fungus Entomophthora muscae in houseflies, where infected flies climb to elevated positions and die, releasing infectious conidia. We performed dual-RNA sequencing of fly he...

The many microbial communities around us form interactive and dynamic ecosystems called microbiomes. Though concealed from the naked eye, microbiomes govern and influence macroscopic systems including human health, plant resilience, and biogeochemical cycling. Such feats have attracted interest from the scientific community, which has recently turn...

Background The site frequency spectrum summarizes the distribution of allele frequencies throughout the genome, and it is widely used as a summary statistic to infer demographic parameters and to detect signals of natural selection. The use of high-throughput low-coverage DNA sequencing data can lead to biased estimates of the site frequency spectr...

The genus Metarhizium comprises a set of diverse entomopathogenic fungi that exhibit a wide spectrum of host ranges. Specifically, M. acridum is a specialist pathogen that infects insects in the order Orthoptera, and is currently used as an environmentally friendly biological control agent. Despite being a species with a global distribution across...

Fungi in the genus Metarhizium are soil-borne plant-root endophytes and rhizosphere colonisers, but also potent insect pathogens with highly variable host ranges. These ascomycete fungi are predominantly asexually reproducing and ancestrally haploid, but two independent origins of persistent diploidy within the Coleoptera-infecting M. majus species...

Fungi in the genus Metarhizium are soil-borne plant-root endophytes and rhizosphere colonisers, but also potent insect pathogens with highly variable host ranges. These ascomycete fungi are predominantly asexually reproducing and ancestrally haploid, but two independent origins of persistent diploidy within the Coleoptera-infecting M. majus species...

The fungus Neonectria neomacrospora has recently caused an epidemic outbreak in conifer species within the genus Abies in Denmark and Norway. Christmas tree producers in Europe and North America rely, to a large extent, on Abies species. The damage caused by N. neomacrospora, including dead shoot tips, red flagging of branches and potentially dead...

Abstract Twenty-nine provenances of teak (Tectona grandis Linn. f.) representing the full natural distribution range of the species were genotyped with microsatellite DNA markers to analyse genetic diversity and population genetic structure. Provenances originating from the semi-moist east coast of India had the highest genetic diversity while prov...

Interspecific hybridization may lead to novel hybrid lineages and transfer of genetic material, possibly enabling species to expand into new habitats. Alternatively, hybrids may be inviable or sterile, constraining movement of parental species and genes into each others range. Pyrola minor (L.) and Pyrola grandiflora (Rad.) hybridize on Disko Islan...