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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.

2025

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Abstract

Citripar, a biological plant protection product containing the parasitic wasp Anagyrus vladimiri, is requested to be approved for use in Norway. The product is intended to be used against mealybugs, particularly Planococcus citri (citrus mealybug) and Planococcus ficus (vine mealybug) feeding on fruits, berries, vegetables and herbs in greenhouses and plastic tunnels, and on indoor plants. The Norwegian Food Safety Authority, therefore, asked the Norwegian Scientific Committee for Food and Environment to perform a risk assessment of the product. Occurrence and distribution in Norway: No observations of Anagyrus vladimiri have been reported from Norway. Potential for establishment and spread: VKM assesses that Anagyrus vladimiri will not be able to establish and spread in Norway under current conditions due to the absence of host organisms and too low winter temperatures, even in the warmest parts of the country. Potential effects on biodiversity: VKM assesses that Anagyrus vladimiri will not affect biodiversity in Norway, as there are currently no known native hosts for the wasp to parasitize. Taxonomic challenges that may affect the risk assessment: Anagyrus vladimiri belongs to the wasp family Encyrtidae, a family that includes the genus Anagyrus, many of which have quite tangled taxonomic histories. Individuals of what is now known as Anagyrus vladimiri were for many years identified as belonging to Anagyrus pseudococci. Anagyrus pseudococci and A. vladimiri are members of a complex of nearly indistinguishable species that are informally referred to as the Anagyrus pseudococci complex: A. pseudococci, A. vladimiri, A. kamali, A. dactylopii, A. kivuensis, and A. callidus. These species have been used for biological control of various mealybug species. Should incorrectly identified Anagyrus be imported to Norway, there would be no consequences for biological diversity, since the other species in the Anagyrus pseudococci complex are also host specific to mealybug genera that are not found in the Norwegian fauna, and they are physiologically unfit for the current Norwegian climate.

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Abstract

Potato production is hindered by soil degradation and nematode infestation. Mineral fertilizers and synthetic nematicides are costly and cause negative impacts on humans and the environment, while organic fertilizers are less effective for soil health and nematode management. This study demonstrates the contribution of black soldier fly frass fertilizer (BSFFF) in nematode suppression and potato productivity when compared to commercial mineral fertilizer, organic fertilizer (SAFI), and nematicide. The on-farm experiments consisted of eight treatments: BSFFF, SAFI, BSFFF+5%chitin, NPK+nematicide, 50%BSFFF+50%NPK, 50%SAFI+50%NPK, 50%BSFFF+5% chitin+50%NPK, and control (unfertilized soil). Results revealed that all fertilizer treatments significantly increased potato growth, number of tubers (34 – 61%), and tuber yield (20 – 72%) relative to the control. Application of BSFFF+5% chitin produced 9 – 28% higher tubers per plant compared to other treatments. Over 26% higher tuber yield was achieved using BSFFF+5% chitin compared to NPK+nematicide treatment. Soil amendment with BSFFF+5% chitin caused 5–35% higher reduction in the number of cysts per 200 g soil-1 compared to NPK+nematicide and SAFI treatments. The same treatment reduced the PCN reproduction rate by 20% and 75% compared to NPK + nematicide and SAFI, respectively. Both BSFFF and NPK+nematicide treatments achieved comparable suppression of the number of eggs and infective juveniles (J2) per cyst-1 and eggs g-1 of soil. However, BSFFF+5% chitin reduced the number of eggs and J2 per cyst-1 and eggs g-1 of soil by 55–92% compared to SAFI. Our findings demonstrate that chitin-fortified BSFFF can significantly contribute to potato cyst nematode suppression and boost potato yields in smallholder farming systems, thus, making it a promising and sustainable alternative to commercial fertilizers and nematicides. Adopting this regenerative and multipurpose fertilizer will reduce reliance on synthetic fertilizers and nematicides, which are costly and harmful to the environment and human health.

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Abstract

The phenylpropanoid pathway, regulated by transcription factors of the MYB family, produces secondary metabolites that play important roles in fertilization and early phase of fruit development. The MYB46 transcription factor is a key regulator of secondary cell wall structure, lignin and flavonoid biosynthesis in many plants, but little is known about its activity in flowers and berries in F. vesca. For functional analysis of FvMYB46, we designed a CRISPR-Cas9 construct with an endogenous F. vesca-specific U6 promoter for efficient and specific expression of two gRNAs targeting the first exon of FvMYB46. This generated mutants with an in-frame 81-bp deletion of the first conserved MYB domain or an out-of-frame 82-bp deletion potentially knocking out gene function. In both types of mutant plants, pollen germination and fruit set were significantly reduced compared to wild type. Transcriptomic analysis of flowers revealed that FvMYB46 positively regulates the expression of genes involved in processes like xylan biosynthesis and metabolism, homeostasis of reactive oxygen species (ROS) and the phenylpropanoid pathway, including secondary cell wall biosynthesis and flavonoid biosynthesis. Genes regulating carbohydrate metabolism and signalling were also deregulated, suggesting that FvMYB46 might regulate the crosstalk between carbohydrate metabolism and phenylpropanoid biosynthesis. In the FvMYB46-mutant flowers, the flavanol and flavan-3-ol contents, especially epicatechin, quercetin-glucoside and kaempferol-3-coumaroylhexoside, were reduced, and we observed a local reduction in the lignin content in the anthers. Together, these results suggest that FvMYB46 controls fertility and efficient fruit set by regulating the cell wall structure, flavonoid biosynthesis, carbohydrate metabolism, and sugar and ROS signalling in flowers and early fruit development in F. vesca.

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Existing methods for resource nexus analysis do not cover all aspects of complex resource management problems. Key methodological challenges include setting the scale, scope, and resolution of a nexus analysis, as well as adequately representing the quantity and quality of resource interactions. Additionally, determining the degree of collaborative governance for resource management, accounting for the role of existing policies, and developing robust scenarios for future predictions are also crucial constraints. To address these limitations, we developed a conceptual model of the resources nexus for Otta valley in Norway, an area characterized by resource use trade-offs across interconnected systems. We introduced the concept of ‘‘resource scapes’’ which is the physical availability, key interactions, management networks, and policies governing a resource at a specific time and place. We defined resource scapes for water, energy, and biomass resources in the studied area. Employing stock and flow loops, social network analysis, material flow accounting, and policy reviews, we developed the model in a layered topology using the coupled component modeling approach. In addition, we developed future resource scenarios nested within national pathways– the Norwegian nexus pathways (NNPs)– aligned with the five globally adopted shared-socioeconomic pathways (SSPs), using a narrative downscaling approach. Our results show that annual variations in resource balances are connected to changing externalities. A low Network External-Internal (EI) index (0.392) indicates weak overall collaborative governance of nexus resources. Our modeling framework (1) addresses limitations in current nexus methods, (2) facilitates testing of alternative policy interventions under future scenarios, and (3) provides a framework for development of integrated assessment models. This approach merges the concept of nexus governance with integrated assessment modeling, thereby enhancing the application of nexus approach for efficient resource management which will be crucial in future as climate and socioeconomic conditions evolve.

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Abstract

Land-use changes threaten ecosystems and are a major driver of species loss. Plants may adapt or migrate to resist global change, but this can lag behind rapid anthropogenic changes to the environment. Our data show that natural modulations of the microbiome of grassland plants in response to experimental land-use change in a common garden directly affect plant phenotype and performance, thus increasing plant tolerance. In contrast, direct effects of fertilizer application and mowing on plant phenotypes were less strong. Land-use intensity-specific microbiomes caused clearly distinguishable plant phenotypes also in a laboratory experiment using gnotobiotic strawberry plants in absence of environmental variation. Therefore, natural modulations of the plant microbiome may be key to species persistence and ecosystem stability. We argue that a prerequisite for this microbiome-mediated tolerance is the availability of diverse local sources of microorganisms facilitating rapid modulations in response to change. Thus, conservation efforts must protect microbial diversity, which can help mitigate the effects of global change and facilitate environmental and human health.

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Algal-based wastewater remediation systems (phycoremediation) include phycosphere bacterial communities that influence algal growth, pollutant remediation, and downstream applications of biomass as fertilizers or bio-stimulants. This study investigated the bacterial community dynamics in a novel phycoremediation system using a co-culture of the green algae Stigeoclonium sp. and Oedogonium vaucheri. Bacterial abundance was estimated using flow cytometry (FCM), while community composition was assessed through 16S rRNA gene metabarcoding. Additionally, 28 bacterial strains were isolated from the bioremediation experiment, cultured, genetically characterized for identification and screened for production of the auxin phytohormone indole-3-acetic acid (IAA). Metabarcoding showed that the free-living bacterial community consisted of bacteria from both the wastewater effluent and the algal inocula, while the attached phycosphere community was dominated by bacteria from the algal inocula, indicating the stability of the algae-associated phycosphere. Taxa known to include plant growth-promoting bacteria (PGPB) were abundant, and several strains produced IAA. The bacterial community composition, combined with the potential production of phytohormone by isolated bacteria indicates symbiotic or commensal algae-microbe interactions within the phycosphere bacterial communities. Sterile filtration of wastewater effluent, including only the algal inoculum bacterial communities, reduced algal biomass production and increased bacterial abundance. This study highlights the critical role of microbial interactions in engineered ecosystems and provides insights for optimizing algal-based wastewater treatment technologies.

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Increasing species diversity in agroecosystems appears as a promising venue to restore or increase soil organic carbon (SOC). It has been hypothesized that this effect is largely driven by the greater variation of root systems in plant mixtures, which may promote complementarity. However, the magnitude of this synergistic effect and the root traits driving it are uncertain. The objective of this study is to determine which root trait composition optimizes plant mixture effects on SOC. To do so, we combined a global meta-analysis of 407 paired SOC content observations under mixed species vs. monocultures across grasslands and croplands, and root traits extracted from the GRooT database. The results show that high root mycorrhizal colonization and root tissue density for the species in the mixture have higher positive effects on SOC content. Our analysis also indicates that combining species with high similarity for these traits represents a preferable trait combination to increase SOC with plant mixtures, challenging the current paradigm around plant trait complementarity effects. We observed that the positive response of SOC content to species mixtures was tightly associated with increased root biomass and soil microbial biomass carbon, indicating an important contribution of belowground and microbial residuals to SOC. Additionally, SOC enhancements by plant species mixtures were more likely to be realized in regions with high precipitation, clay-rich soils, and when legumes are present. Our meta-analysis lays out a root-trait framework to enhance SOC with plant mixtures, which can serve as a guide for species and variety selection for field experiments and on-farm applications.

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Potato Fusarium dry rot and wilt are the most important soil- and seed-borne diseases in potatoes. They cause high economic losses during potato growth and storage across the world. Previous observations have shown that dryocrassin ABBA can induce resistance in potatoes. However, little is known about whether dryocrassin ABBA can suppress Fusarium oxysporum. In this research, we determined that exogenous dryocrassin ABBA significantly inhibited the mycelial growth, changed the cell ultrastructure, increased the MDA content, and decreased the antioxidant enzyme activity of F. oxysporum. The transcriptome analysis of F. oxysporum with or without dryocrassin ABBA indicated that 1244 differentially expressed genes (DEGs) were identified, of which 594 were upregulated and 650 were downregulated. GO term analysis showed that the DEGs were mostly related to biological processes. The KEGG pathway was mainly related to carbohydrate, amino acid, and lipid metabolism. Moreover, most of the expressions of PCWDEs, HSPs, and MFS were downregulated, decreasing the stress capacity and weakening the pathogenicity of F. oxysporum with dryocrassin ABBA treatment. These findings contribute to a new understanding of the direct functions of dryocrassin ABBA on F. oxysporum and provide a potential ecofriendly biocontrol approach for potato Fusarium dry rot and wilt