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

Formålet med forprosjektet VitalEPLEJORD var å studere potensielle årsaker til jordtrøtthet i epleproduksjonen, et fenomen som kan oppstå dersom det ikke praktiseres vekstskifte. Jordprøver fra 10 bruk (fem med økologisk og fem med konvensjonell drift) på Øst- og Vestlandet ble undersøkt med tanke på jordkvalitet, nematoder og Phytophthora. Innen hver av de tre kategoriene ble det gjort interessante funn. Både lite fruktbar jord og skadegjørere kan føre til dårlig etablering, svak tilvekst, avlingsreduksjon og at trær i verste fall dør. I de jordkjemiske analysene ble det vist høyere innhold av organisk materiale, totalt nitrogen og plantetilgjengelig fosfor i økologisk enn konvensjonell drift, samt mer stabilt innhold av plantetilgjengelig magnesium, mer stabil pH og mer stabil basemetningsgrad. Det ble identifisert en rekke nematodearter, inkludert flere planteparasittære. Økologisk drift så ut til å kunne øke bakteriekonsumerende nematoder, minske rotkonsumerende nematoder og øke altetere. Innen Phytophthora ble det funnet fire arter der alle er rapportert som alvorlige skadegjørere på treaktige vekster både i Norge og andre land. Phytophthora forekom ved begge driftsformer. Antallet jordprøver var totalt 50 (5 samleprøver/bruk, hver samleprøve kom fra separate rader). Testomfanget var for lite til å dra konklusjoner om årsak til jordtrøtthet, men det har gitt verdifull kunnskap til å bygge videre på.

Sammendrag

Denne rapporten omhandler arbeid som NIBIO har utført på oppdrag fra Mattilsynet vedr.Kartleggingsprogrammet i 2019 for nematoder og Phytophthora spp. i jord på importerte planter, startet i april og sluttet 31. desember. Ok-programmet omfattet også undersøkelser av Phytophthora spp se egen rapport. Denne delen av rapporten er for nematoder. Programmet hadde hovedfokus på import av store trær med stor jordklump som er dyrka på friland og evt. planter i organisk dyrkingsmedium som kan tenkes å ha opprinnelse utenfor Europa. Mattilsynet valgte ut importsendinger og var ansvarlig for prøvetakingen. Programmet ble startet I 2018 og fortsatte i 2109.

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Sammendrag

Shallot (Allium cepa var. aggregatum), a small bulb onion, is widely grown in the world. We previously reported a droplet-vitrification for cryopreservation of in vitro-grown shoot tips of shallot genotype ‘10603’. The present study further evaluated rooting, vegetative growth, bulb production and contents of biochemical compounds, as well as genetic stability in cryo-derived plants. The results showed no significant differences in rooting, vegetative growth, bulb production and contents of soluble sugars and flavonols between the cryo- and in vitro-derived plants. Analyses of ISSR and AFLP markers did not detect any polymorphic bands in the cryo-derived plants. These results indicate rooting and vegetative growth ability, biochemical compounds and genetic stability were maintained in cryo-derived plants. The present study provides experimental evidences that support the use of cryopreservation method for long-term preservation of genetic resources of shallots and other Allium species.

Sammendrag

Rotgall nematoder (Meloidogyne spp.) er globalt de mest skadelige nematodene, og forårsaker mer enn 10 % av avlingsreduksjonen på verdensbasis. M. arenaria, M. javanica, M. incognita og M. hapla er de viktigste artene. Totalt er det beskrevet mer enn 90 arter av otgallnematoder, og av disse er ca. 20 så langt blitt funnet i Europa. M. chitwoodi and M. fallax betraktes som en trussel for Europa og begge artene forårsaker alvorlige kvalitetsskader på potet og grønnsaker som gulrot. På det europeiske kontinentet er M. hapla mest utbredt, mens M.chitwoodi og M. fallax er påvist i begrensede områder....

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The present study described a combining thermotherapy with meristem culture for improved eradication of onion yellow dwarf virus (OYDV) and shallot latent virus (SLV) from co‐infected in vitro‐cultured shallot shoots. In vitro‐cultured shoots infected with OYDV and SLV were thermo‐treated at a constant temperature of 36°C for 0, 2 and 4 weeks, and then meristems (0.5 mm) containing 1–2 leaf primordia were excised and cultured for shoot regrowth. Meristem culture without thermotherapy produced much higher levels of survival (100%) and shoot regrowth (55%) than those (62% survival and 32% shoot regrowth) produced by the procedure combining 4 weeks of thermotherapy with meristem culture. However, much higher virus‐free frequencies (70% for OYSV, 80% for SLV and 50% for both viruses) were obtained in the latter than those (10% for OYSV, 15% for SLV and 10% for both viruses) obtained in the former. Histological and subcellular studies showed that thermotherapy imposed stress or damage to the cells of meristems, thus resulting in reduced meristem survival and shoot regrowth. Studies on virus location revealed considerable alternations of virus distribution patterns in the thermo‐treated meristems. The results of histological and subcellular studies and analysis of virus distribution pattern added valuable experimental data in the combining thermotherapy with meristem culture for virus eradication. These data provided explanations as to why combining thermotherapy with meristem culture improved the eradication of OYDV and SLV from the virus‐infected in vitro shallot shoots.

Sammendrag

Lys ringråte på potet, forårsaket av bakterien Clavibacter michiganensis subspecies sepedonicus (Cms), har gjort mye skade i norsk potetproduksjon siden første påvisning i landet i 1964. Den er også grunnen til at man ikke kan eksportere poteter fra Norge. Siden 1965 har Norge hatt sitt eget, nasjonale regelverk for bekjempelse av bakterien. Man har tidligere ( før 1980) flere ganger uten hell forsøkt å utrydde sykdommen fra flere deler av landet. Dette fordi mangelen på en påvisningsmetode med tilstrekkelig sensitivitet den gangen gjorde det vanskelig å skaffe de nødvendige mengder sykdomsfrie settepoteter til utskiftingen...

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Sweet potato (Ipomoea batatas (L.) Lam.) is an important root crop for poor farmers in developing countries. Since the late 1980s, viral diseases have increasingly become a threat to sweet potato production in Ethiopia. This review paper presents the role of sweet potato production for ensuring food security, the level of sweet potato virus research, including the types of viral species identified and their current level of incidences in Ethiopia. Sweet potato feathery mottle virus (SPFMV), Sweet potato chlorotic stunt virus (SPCSV), Sweet potato virus 2 (SPV2), Sweet potato virus G (SPVG), and Cucumber mosaic virus (CMV) were reported in Ethiopia, where the first two are the most common and exist at high incidences. In addition, this paper discusses the virus vectors, virus transmission methods to new farms, factors exacerbating the rate of viral incidence and the methods used to reduce the incidences. Moreover, it highlights methods of sweet potato viruses’ detection and cleaning of infected materials in use and the challenges encountered towards the efficient utilization of the methods. Finally, we suggest major intervention techniques that will integrate all key players in managing the impact of the virus on sweet potato production to improve productivity and ensuring food security in Ethiopia. The findings obtained from this review could be an input for the current research on sweet potato improvement (both planting materials and routines) in Ethiopia.

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Recently developed CRISPR-mediated base editors, which enable the generation of numerous nucleotide changes in target genomic regions, have been widely adopted for gene correction and generation of crop germplasms containing important gain-of-function genetic variations. However, to engineer target genes with unknown functional SNPs remains challenging. To address this issue, we present here a base-editing-mediated gene evolution (BEMGE) method, employing both Cas9n-based cytosine and adenine base editors as well as a single-guide RNA (sgRNA) library tiling the full-length coding region, for developing novel rice germplasms with mutations in any endogenous gene. To this end, OsALS1 was artificially evolved in rice cells using BEMGE through both Agrobacterium-mediated and particle-bombardment-mediated transformation. Four different types of amino acid substitutions in the evolved OsALS1, derived from two sites that have never been targeted by natural or human selection during rice domestication, were identified, conferring varying levels of tolerance to the herbicide bispyribac-sodium. Furthermore, the P171F substitution identified in a strong OsALS1 allele was quickly introduced into the commercial rice cultivar Nangeng 46 through precise base editing with the corresponding base editor and sgRNA. Collectively, these data indicate great potential of BEMGE in creating important genetic variants of target genes for crop improvement.

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Wheat dwarf virus (WDV), a mastrevirus transmitted by the leafhopper Psammotettix alienus, causes a severe disease in cereal crops. Typical symptoms of wheat plants infected by WDV are yellowing and severe dwarfing. In this present study, RNA-Seq was used to perform gene expression analysis in wheat plants in response to WDV infection. Comparative transcriptome analysis indicated that a total of 1042 differentially expressed genes (DEGs) were identified in the comparison between mock and WDV-inoculated wheat plants. Genomes ontology (GO) annotation revealed a number of DEGs associated with different biological processes, such as phytohormone metabolism, photosynthesis, DNA metabolic process, response to biotic stimulus and defense response. Among these, DEGs involved in phytohormone and photosynthesis metabolism and response pathways were further enriched and analyzed, which indicated that hormone biosynthesis, signaling and chloroplast photosynthesis-related genes might play an important role in symptom development after WDV infection. These results illustrate the dynamic nature of the wheat-WDV interaction at the transcriptome level and confirm that symptom development is a complex process, providing a solid foundation to elucidate the pathogenesis of WDV.