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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.

2023

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Stress can have long-lasting impacts on plants. Here we report the long-term effects of the stress hormone jasmonic acid (JA) on the defence phenotype, transcriptome and DNA methylome of Arabidopsis. Three weeks after transient JA signalling, 5-week-old plants retained induced resistance (IR) against herbivory but showed increased susceptibility to pathogens. Transcriptome analysis revealed long-term priming and/or upregulation of JA-dependent defence genes but repression of ethylene- and salicylic acid-dependent genes. Long-term JA-IR was associated with shifts in glucosinolate composition and required MYC2/3/4 transcription factors, RNA-directed DNA methylation, the DNA demethylase ROS1 and the small RNA (sRNA)-binding protein AGO1. Although methylome analysis did not reveal consistent changes in DNA methylation near MYC2/3/4-controlled genes, JA-treated plants were specifically enriched with hypomethylated ATREP2 transposable elements (TEs). Epigenomic characterization of mutants and transgenic lines revealed that ATREP2 TEs are regulated by RdDM and ROS1 and produce 21 nt sRNAs that bind to nuclear AGO1. Since ATREP2 TEs are enriched with sequences from IR-related defence genes, our results suggest that AGO1-associated sRNAs from hypomethylated ATREP2 TEs trans-regulate long-lasting memory of JA-dependent immunity.

Sammendrag

The maturity stage of carrot and the temperature strategy during storage are essential factors in maintaining storage quality during long-term storage. The aim of the study was to examine the effect of maturity and storage strategy on storage quality in different cultivars of carrot (Daucus carota subsp. sativus). Two cultivars, ‘Nominator’ and ‘Romance’, harvested at three different maturity levels were stored with different temperature strategies in small-scale experimental stores. The different maturity levels were obtained by different sowing dates. The study was conducted over 2 years and storage seasons in 2019-2020 and 2020-2021. The carrots were stored with three different temperature strategies with stable temperature at 0, 2 or 0°C interrupted with intervals of 2 weeks with 4°C in February and in March. After six-months storage we found that weight loss was higher (7.8%) after storage when the temperature was not stable during storage (fluctuations up to 4°C in February and March) than at stable temperatures at 0 or 2°C. The number of healthy roots after storage was highest in the most mature carrots (91%) while there were less healthy roots in the least mature roots (85%) (P<0.05). Diseases detected after storage were gray mold (Botrytis cinerea), liquorice rot (Mycocentrospora acerina), tip rot, crater rot (Fibularhizoctonia carotae), Fusarium rot (Fusarium spp.) and cavity spot (Pythium spp.). There was significantly more liquorice rot in Nominator (1.9%) than in Romance (0.6%). There was more tip rot in the least mature carrots (3.3%) compared to the other two maturity levels (1.3 and 1.5%).

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Black soldier fly larvae (BSFL) Hermetia illucens is fastest growing and most promising insect species especially recommended to bring high-fat content as 5th generation bioenergy. The fat content can be fully optimized during the life-cycle of the BSFL through various organic dietary supplements and environmental conditions. Enriched fat can be obtained during the larval stages of the BSF. The presence of high saturated and unsaturated fatty acids in their body helps to produce 70 % of extractable oil which can be converted into biodiesel through transesterification. The first-generation biodiesel process mainly depends on catalytic transesterification, however, BSFL had 94 % of biodiesel production through non-catalytic transesterification. This increases the sustainability of producing biodiesel with less energy input in the process line. Other carbon emitting factors involved in the rearing of BSFL are less than the other biodiesel feedstocks including microalgae, cooking oil, and non-edible oil. Therefore, this review is focused on evaluating the optimum dietary source to produce fatty acid rich larvae and larval growth to accumulate C16–18 fatty acids in larger amounts from agro food waste. The process of optimization and biorefining of lipids using novel techniques have been discussed herein. The sustainability impact was evaluated from the cultivation to biodiesel conversion with greenhouse gas emissions scores in the entire life-cycle of process flow. The state-of-the-art in connecting circular bioeconomy loop in the search for bioenergy was meticulously covered.

Sammendrag

Carrot is the main field vegetable in Norway and is stored at 0-1°C for up to 8 months. In long-stored carrots, postharvest diseases are problematic. Better knowledge of the causal agents of postharvest diseases can help producers apply appropriate control measures to reduce carrot loss and waste. The objectives of this study were to determine the extent of the tip rot problem and the prevalence of other storage diseases of carrots in different regions in Norway. The study was conducted from 2019 to 2021 by collecting carrots from 16 commercial cold storages, representing four regions. From each storage, representative carrots were randomly sampled, washed, and sorted into different disease categories and healthy carrots. Representative samples from each category were further analyzed in the NIBIO laboratory to identify the causal agent(s) and confirm the disease. Causal agent(s) were identified by symptom and sign description, microscopy and when necessary, DNA sequencing. One or more pathogens were identified from each symptomatic carrot. The incidence of postharvest diseases significantly varied among regions. Taking all years and regions together, only 42% of the carrots were healthy. In other words, 58% of the carrots were with one or more diseases, representing a waste due to diseases alone. Tip rot alone contributed to about 30% of the postharvest loss. Our results indicate that the burden of postharvest diseases of carrots is increasing. This includes diseases like tip rot disease complex, Cylindrocarpon root rot and cavity spot. The results are useful to direct research investigation of the most problematic diseases. Most of the post-harvest diseases of carrots are the result of latent infections that occur in the field, and stress during handling, storage, and processing operations. Hence, postharvest disease control measures should consider the pre-and postharvest predisposing factors of carrots for storage rot.

2022

Sammendrag

Stigende pris på nitrogengjødsel gjør bruk av belgvekster i eng og beite aktuelt for flere. Belgvekstene har en unik evne til å samle nitrogen fra lufta og gir god avling og proteinrikt fôr. Flere arter og nye sorter av engbelgvekster har blitt prøvd ut over hele landet.

Sammendrag

Denne rapporten oppsummerer to interessegruppemøter arrangert for landbruket. Noen brukerbehov kan innfris innenfor prosjektene, men det er sprik mellom hva forskningsprosjekter kan levere og hva interessegruppen har behov for, slik at ikke alle ønsker kan innfris. Enkelte ønsker har blitt videreformidlet til værvarslingstjenesten. Som et svar på brukerbehov etter interessegruppemøtet i 2022 beregnet vi tetraterm (varmekrav for ulike treslag i sommermånedene), inkludert endringer i tetraterm over tid. Tetratermen har økt i hele landet, og med det øker den potensielle utbredelsen av varmekjære trær. I den nettbaserte versjonen av rapporten beskrives også eksisterende dataportaler mer inngående, noe interessegruppen har etterspurt.

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Lack of national soil property maps limits the studies of soil moisture (SM) dynamics in Norway. One alternative is to apply the global soil data as input for macro-scale hydrological modelling, but the quality of these data is still unknown. The objectives of this study are 1) to evaluate two recent global soil databases (Wise30sec and SoilGrids) in comparison with data from local soil profiles; 2) to evaluate which database supports better model performance in terms of river discharge and SM for three macro-scale catchments in Norway and 3) to suggest criteria for the selection of soil data for models with different complexity. The global soil databases were evaluated in three steps: 1) the global soil data are compared directly with the Norwegian forest soil profiles; 2) the simulated discharge based on the two global soil databases is compared with observations and 3) the simulated SM is compared with three global SM products. Two hydrological models were applied to simulate discharge and SM: the Soil and Water Integrated Model (SWIM) and the Variable Infiltration Capacity (VIC) model. The comparison with data from local soil profiles shows that SoilGrids has smaller mean errors than Wise30sec, especially for upper soil layers, but both soil databases have large root mean squared errors and poor correlations. SWIM generally performs better in terms of discharge using SoilGrids than using Wise30sec and the simulated SM has higher correlations with the SM products. In contrast, the VIC model is less sensitive to soil input data and the simulated SM using Wise30sec is higher correlated with the SM products than using SoilGrids. Based on the results, we conclude that the global soil databases can provide reasonable soil property information at coarse resolutions and large areas. The selection of soil input data should depend on the characteristics of both models and study areas.