Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2020
Sammendrag
Recent discoveries have highlighted multiple mitotically and meiotically inherited alterations in gene expression that could not be explained solely by changes in the DNA sequence but were acknowledged as epigenetic. The modern view on epigenetics considers it as an integral part of genetics. Epigenetic mechanisms are encoded by genes in the genome and contribute to an essential part of genomic diversity, significantly extending its regulatory abilities. Epigenetic mechanisms involve molecular chromatin alterations through DNA methylation and histone modifications, as well as, complex non-coding RNAs and related enzyme machinery leading to changes in gene expression and resulting in changing phenotypes. In plants, epigenetic mechanisms may occur over their lifetime and across multiple generations, and can contribute substantially to phenotypic plasticity, stress responses, disease resistance, acclimation and adaptation to habitat conditions. In this review, we summarize recent advances with regards to Norway spruce epigenomics. We first consider the large size of the spruce genome that is linked to epigenetic mechanisms and why epigenomics is vitally important for spruce. Then, we discuss the molecular machinery supporting epigenetic mechanisms in Norway spruce and putative gene models involved. We presume substantial extension of gene families of epigenetic regulators and non-coding RNAs, especially in reproductive tissues. Norway spruce was the first species among forest trees in which epigenetic memory and epigenetic mechanisms were studied. The induction of an epigenetic memory during sexual reproduction and somatic embryogenesis has been described in Norway spruce. We discuss the latest results of epigenomic variation and epigenetic memory studies in Norway spruce and define the future perspectives for epigenetic studies. However, there is still a long way to decipher how the epigenetic mechanisms are involved in maintaining the stability of the spruce epigenome, how the epigenome is set to produce the epigenetic memory phenomenon and how these may result in an increased rate of adaptation to a changing environment.
Forfattere
Rosemary Collier Dominique Mazzi Annette Folkedal Schjøll Quentin Schorpp Gunda Thöming Tor J. Johansen Richard Meadow Nicolai Vitt Meyling Anne-Marie Cortesero Ute Vogler Michael T. Gaffney Martin HommesSammendrag
Several important vegetable crops grown outdoors in temperate climates in Europe can be damaged by the root-feeding larvae of Diptera (Delia radicum, Delia floralis, Chamaepsila rosae, Delia platura, Delia florilega, Delia antiqua). Knowledge of pest insect phenology is a key component of any Integrated Pest Management (IPM) strategy, and this review considers the methods used to monitor and forecast the occurrence of root-feeding flies as a basis for decision-making by growers and the ways that such information can be applied. It has highlighted some current management approaches where such information is very useful for decision support, for example, the management of C. rosae with insecticidal sprays and the management of all of these pests using crop covers. There are other approaches, particularly those that need to be applied at sowing or transplanting, where knowledge of pest phenology and abundance is less necessary. Going forward, it is likely that the number of insecticidal control options available to European vegetable growers will diminish and they will need to move from a strategy which often involves using a single ‘silver bullet’ to a combination of approaches/tools with partial effects (applied within an IPM framework). For the less-effective, combined methods, accurate information about pest phenology and abundance and reliable decision support are likely to be extremely important.
Sammendrag
Genetic selection in commercial sheep production has mainly focussed on production traits and to a large extent ignoring behavioural traits, such as response towards predators. The Icelandic leadersheep is a sheep breed selected and known for its special behavioural traits, such as leading the flock and bringing it home from pasture in case of danger. Those traits are also said to be beneficial in areas with a high predator pressure. In this study, it was investigated if there are behavioural differences in sheep flocks with and without a leadersheep present. Behaviour of sheep flocks was observed before, during and after a predator test, in small groups of Icelandic sheep with or without a leadersheep in the group. Eleven groups of Icelandic sheep with six ewes in each group were observed in a test arena while a human, a dog and a drone passed through the pasture. Six of the groups included a leadersheep and the remaining five did not. Groups including a leadersheep spent more time grazing after both the human and dog test, indicating a faster recovering to normal behaviour. They were also located close to the exit during the dog test compared to groups without a leadersheep, fitting well with the assertion that leadersheep bring the flock home in case of danger. During the drone test, groups with a leadersheep however spent more time moving around compared to the other groups. Since the sheep had experienced both humans and dogs before, but not drones, this may indicate that groups with leadersheep recovered quickly from the figurants they had experienced before, but tended to react more in the test which was a new situation. In conclusion, it appears likely that the earlier selection for leader traits in the leadersheep have indeed changed both their own behaviour and also that this has an effect on the behaviour of group members.
Forfattere
Aurita Butkeviciute Mindaugas Liaudanskas Darius Kviklys Dalia Gelvonauskiene Valdimaras JanulisSammendrag
As the interest in heirloom cultivars of apple trees, their fruit, and processed products is growing worldwide, studies of the qualitative and quantitative composition of biological compounds are important for the evaluation of the quality and nutritional properties of the apples. Studies on the variations in the chemical composition of phenolic compounds characterized by a versatile biological effect are important when researching the genetic heritage of the heirloom cultivars in order to increase the cultivation of such cultivars in orchards. A variation in the qualitative and quantitative composition of phenolic compounds was found in apple samples of cultivars included in the Lithuanian collection of genetic resources. By the high-performance liquid chromatography (HPLC) method flavan-3-ols (procyanidin B1, procyanidin B2, procyanidin C2, (+)-catechin and (−)-epicatechin), flavonols (rutin, hyperoside, quercitrin, isoquercitrin, reynoutrin and avicularin), chlorogenic acids and phloridzin were identified and quantified in fruit samples of heirloom apple cultivars grown in Lithuania. The highest sum of the identified phenolic compounds (3.82 ± 0.53 mg/g) was found in apple fruit samples of the ‘Koštelė’ cultivar
Forfattere
Michal SposobSammendrag
Det er ikke registrert sammendrag
Forfattere
Ahto Agan Rein Drenkhan Kalev Adamson Leho Tedersoo Halvor Solheim Isabella Børja Iryna Matsiakh Volkmar Timmermann Nina Elisabeth Nagy Ari HietalaSammendrag
European ash (Fraxinus excelsior) is threatened by the invasive ascomycete Hymenoscyphus fraxineus originating from Asia. Ash leaf tissues serve as a route for shoot infection but also as a sporulation substrate for this pathogen. Knowledge of the leaf niche partitioning by indigenous fungi and H. fraxineus is needed to understand the fungal community receptiveness to the invasion. We subjected DNA extracted from unwashed and washed leaflets of healthy and diseased European ash to PacBio sequencing of the fungal ITS1-5.8S-ITS2 rDNA region. Leaflets from co-inhabiting rowan trees (Sorbus aucuparia) served as a reference. The overlap in leaflet mycobiomes between ash and rowan was remarkably high, but unlike in rowan, in ash leaflets the sequence read proportion, and the qPCR-based DNA amount estimates of H. fraxineus increased vigorously towards autumn, concomitant with a significant decline in overall fungal richness. The niche of ash and rowan leaves was dominated by epiphytic propagules (Vishniacozyma yeasts, the dimorphic fungus Aureobasidion pullulans and the dematiaceous hyphomycete Cladosporium ramotenellum and H. fraxineus), and endophytic thalli of biotrophs (Phyllactinia and Taphrina species), the indigenous necrotroph Venturia fraxini and H. fraxineus. Mycobiome comparison between healthy and symptomatic European ash leaflets revealed no significant differences in relative abundance of H. fraxineus, but A. pullulans was more prevalent in symptomatic trees. The impacts of host specificity, spatiotemporal niche partitioning, species carbon utilization profiles and life cycle traits are discussed to understand the ecological success of H. fraxineus in Europe. Further, the inherent limitations of different experimental approaches in the profiling of foliicolous fungi are addressed.
Sammendrag
An understanding of the relationship between volume increment and stand density (basal area, stand density index, etc.) is of utmost importance for properly managing stand density to achieve specific management objectives. There are two main approaches to analyse growth–density relationships. The first relates volume increment to stand density through a basic relationship, which can vary with site productivity, age, and potentially incorporates treatment effects. The second is to relate the volume increment and density of thinned experimental plots relative to that of an unthinned experimental plot on the same site. Using a dataset of 229 thinned and unthinned experimental plots of Norway spruce, a growth model is developed describing the relationship between gross or net volume increment and basal area. The models indicate that gross volume increases with increasing basal area up to 50 m2 and thereafter becomes constant out to the maximum basal area. Alternatively, net volume increment was maximized at a basal area of 43 m2 and decreased with further increases in basal area. However, the models indicated a wide range where net volume increment was essentially constant, varying by less than 1 m3 ha−1 year−1. An analysis of different thinning scenarios indicated that the relative relationship between volume increment and stand density was dynamic and changed over the course of a rotation.
Forfattere
Kamilla Skaalsveen Julie Ingram Julie UrquhartSammendrag
This paper draws on network science and uses a Social Network Analysis to improve our understanding of how the implementation of no-till in England is influenced by farmers' social networks. No-till is a low disturbance farming practice with potential to benefit soil health, the aquatic environment and farm economy, but is currently only implemented at a small scale in Europe. Interpersonal networks are important for farmers and influence farmer learning and decision-making and farmers often view each other as their main source of information. In this study, the social networks of 16 no-till farmers in England were mapped and semi-structured interviews carried out to assess the link between farmer network characteristics and the implementation of no-till in England. We also aimed to improve our understanding of the nature and extent of knowledge exchanged within farmer networks and their spatial and temporal dynamics. Our findings suggest that intermediary farmers had an important role in increasing the information flow and knowledge exchange between the different clusters of the no-till farmer network. These intermediaries were also the biggest influencers as they were often no-till farmers with a high level of experiential knowledge and viewed as important sources of information by other farmers. No-till farmer networks were geographically distributed as the farmers preferred to discuss farming practices with similar minded no-till farmers rather than local conventional farmers who did not understand what they were trying to achieve. Therefore, online communication platforms like social media were important for communication. We question the role of formal extension services in supporting farmers with innovative practices like no-till and suggest that advisors should strive to improve their understanding of these well-developed information networks to enable a more streamlined and efficient information diffusion.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Daniel Flø Trond Rafoss Per Hans Micael Wendell Leif SundheimSammendrag
Background The Siberian moth (Dendrolimus sibiricus) is a serious pest of conifers in Russia, Northern Kazakhstan, Mongolia and China. The western border of the pest’s distribution in Russia is disputed, but it is present west of the 60th meridian east. The pest has the potential to defoliate a wide range of conifers. Results The pest is not present in Norway or other European countries, except Russia. Natural spread and human mediated transport are potential pathways for the pest. Human mediated pathways considered are: Living trees for planting, coniferous wood in the rough and foliage and branches. There has been no import of living trees from Russia to Norway during the past 30 years, and there is currently no import of coniferous wood commodities containing bark from areas, where D. sibiricus occurs. Conclusions The probability of D. sibiricus entry by natural spread is unlikely, mainly because of the geographical distance and the partial sea barriers between Norway and the infested areas. The probability of entry by human mediated pathways is unlikely due to the very limited volume of the import. Should the pest enter Norway, the probability of establishment and spread is unlikely, due to the suboptimal climatic conditions, and the fact that the two dominant conifers in the country, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), are intermediate and poor hosts, respectively. The potential damage, should D. sibiricus enter Norway, is considered low. Keywords: Lepidoptera, Invasive species, Geographical distribution, Forest pest