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.
2011
Forfattere
Xiaoren Chen Sonja Klemsdal May Bente BrurbergSammendrag
The oomycete Phytophthora cactorum can cause economically important diseases on numerous host plants worldwide, such as crown rot on strawberry. To explore the molecular mechanisms underlying the pathogenicity of P. cactorum on strawberry, transcriptional analysis of P. cactorum during strawberry infection and cyst germination was performed by applying suppression subtractive hybridization (SSH) and effector-specific differential display (ESDD) techniques. Two SSH cDNA libraries were generated, enriched for P. cactorum genes expressed during infection or during cyst germination, respectively, and 137 unique differentially expressed genes were identified. To specifically select RxLR effector genes from P. cactorum, ESDD was performed using RxLR and EER motif-based degenerate primers. Eight RxLR effector candidate genes as well as 67 other genes were identified out of 124 selected fragments. The expression levels of 20 putatively up-regulated genes were further analyzed using real-time RT-PCR, showing that, indeed 19 of these 20 genes were up-regulated during at least one of the studied developmental stages or during strawberry crown invasion, relative to the mycelium. This study provides a first overview of P. cactorum genes that are up-regulated immediately prior to or during strawberry infection and also provides a novel method for selecting RxLR effector genes from the unsequenced genome of P. cactorum.
Forfattere
Randi Garmo S Waage S Sviland Britt I.F. HenriksenSammendrag
Hensikten med studien var å sjå om eingongsvurdering av form på spenetupp og speneåpning på NRF-kyr i forskjellige stadium av laktasjonen virka inn på sannsynlegheita for at ein kjertel er infisert med mastittbakteriar. Totalt var 49 besetningar med i undersøkinga. Av desse var 24 økologiske og 25 konvensjonelle, og det var 19 båsfjøs og 30 lausdriftfjøs. Antall dagar i laktasjon eller mjølkemengde fire veker etter kalving hadde ikkje betydning for om ein kjertel var infisert eller ikkje. Derimot var det ein samanheng mellom infiserte kjertlar og forekomst av ru spenering, innkrenga og tilspissa spenetupper, bakjertlar, kua sin alder og celletal. Tidligare har det vore rapportert om 43% flate, 45% runde og 12-13% traktforma ender på spenetuppene på Norsk rødt fe. Det er godt samsvar mellom denne studien og vår studie når det gjeld forekomsten av flate og runde spenetupper. Neijenhuis et al. (2001) rapporterte at traktforma spenetuppar hadde tjukkare og meir ru spenering enn flate og innkrenga spenetupper. Det er rapportert at kyr med innkrenga spenespissar har høgare risiko for lekkasje som igjen er knytta til høgare risiko for mastitt og høgt celletal, medan andre har rapportert at det ikkje er samanheng mellom form på spenetupp og celletal.
Sammendrag
The objective of this study was to evaluate the importance of geographic origin and grazing system for Norwegian and Italian consumers" probability of buying lamb meat. The study consisted of a qualitative part with focus groups followed up with a quantitative survey in each country. Included in the survey was a conjoint design with origin of the meat (Norway, Italy and New Zealand) and pasture (lowland pasture and mountain pasture) as factors, plus questions about consumers" motives underlying selection of food. Results from the study shows that country of origin is important for consumers" buying probability of lamb meat, in both countries domestic meat was preferred. In addition, a higher probability of buying meat from lamb grazing on mountain pasture than from lamb grazing on lowland pasture was identified. It is important for producers of lamb meat to increase the communication of these elements in a competitive national and international food market
Sammendrag
Glen Ample is the main raspberry cultivar in Norway. This cultivar is very susceptible to the raspberry leaf and bud mite Phyllocoptes gracilis, and serious damage on both leaves and fruits are common. The only documented control measure available has been fenpyroximate (Ortus/ Danitron), a substance that can only be used once per growing season, which is not sufficient to keep P. gracilis below damaging population levels. Nor can it be used by organic growers. In a search for alternative control measures we conducted trials with rapeseed oil (emulsified with soft soap) and sulphur (Thiovit Jet) in heavily infested fields. The effect was measured by assessing leaf damage and counting mites overwintering in the buds. The results imply that post harvest spraying with vegetable oils or sulphur targeting overwintering females in the buds is a very valuable component of a management strategy for the leaf and bud mite in ‘Glen Ample’.
Sammendrag
The effect of different light environments on trap catches of Frankliniella occidentalis and Trialeurodes vaporariorum was investigated in a commercial greenhouse rose production unit during late autumn. Two top light treatments were used: 1) High pressure sodium lamps (HPSLs) and 2) HPSLs and light emitting diodes (LEDs) with 20% blue and 80% red light. More thrips and fewer whiteflies were caught on yellow sticky traps, and more thrips were found in the flowers, in areas were LEDs were used in addition to HPSLs compared to areas where only HPSLs were used. No effect of the light treatments was found on the population level of Amblyseius swirskii, but a lower ratio of predatory mites to thrips was found on the plants where LEDs were used. The results suggest that using blue and red LEDs as interlighting, or otherwise supplementary to HPSLs, will change thrips and whitefly spatial distribution in the rose crop, and that natural enemy release rates probably need to be adjusted accordingly.
Forfattere
Ole Tobias Rannestad May-Guri Saethre Amon P. MaerereSammendrag
The banana weevil, Cosmopolites sordidus Germar (Coleoptera: Curculionidae) is a major pest in banana (Musa spp.) growing areas. The weevil is known to be relatively sedentary and closely associated with its host plant, but little is known about the species" ability to migrate between banana fields and in non-host habitats. Mark-recapture experiments were conducted to assess the weevils" migration potential, possible differences between the sexes, and the relative attractiveness of pseudostem and pheromone baits. One thousand two hundred marked weevils were released in non-host habitat at five distances (5, 10, 20, 40 and 70 m) from fresh pseudostem, and from pitfall traps baited with 45 mg Sordidin. Two hundred males and 200 females were marked and released at five distances (5, 10, 20, 40 and 70 m) from pheromone traps. Distance and distance/bait interactions had a significant effect on recaptured weevils (binary logistic regression). The two baits were almost equally attractive to weevils from 0-10 m, while the pheromone was more attractive from 10-100 m. Distance, bait, and distance/bait interactions had a significant effect on the time elapsed from release to recapture (regression with life data). However, the pattern observed was not consistent. There was no significant difference between males and females with respect to distance or time elapsed from release to recapture.
Forfattere
Martin Vohnik Jesse j. Sadowsky Petr Kohout Zuzana Lothakova Rolf Nestby Miroslav KolarikSammendrag
Ericacea are ubiquitous calcifuges that often dominate acidic soils with poor nutrient status. Their nutrition depends on mycorrhizal fungi, which provide access to recalcitrant substrates unavailable to non-mycorrhizal plants. To date, the only experimentally proven ericoid mycorrhizal fungi belong to the Ascomycota. Ericoid mycorrhiza (ErM) with an unusual 1- to 3-layer sheat of clamped hyphae were observed in Vaccinium spp. roots in two habitats in mid-Norway. The respectiv mycobiont was isolated and examined for polygenetic position and ability to form ericoid mycorrhiza. Two conspecific clamp-and cystidia-bearing isolates formed the characteristic sheated ErM and enhanced growth of ericaceous hosts in vitro. Both failed to riably amplify with several common primer combinations (e.g.,ITS1 and ITS1F+ITS4); based on three RNA gene analyses they reside in the proximity of Trechisporales and Hymenochaetales and represent a unique lineage within Agaricomycetes.
Forfattere
Britt I.F. Henriksen Bente Kirkhus Aina LundonSammendrag
Det er eit aukande behov for kvalitetsolje for matkonsum, både nasjonalt og globalt. Samtidig er det mangel på gode eigenproduserte proteinkjelder til økologiske fôrrasjonar, både til drøvtyggarar og einmaga dyr. Prosjektet ”Organic protein feed and edible oil from oilseed crops” (2006-2010) har sett på korleis ulik gjødslingsstrategi påverkar næringsinnhaldet i økologisk dyrka oljevekstar til både fôr og matolje. Artikkelen presenterer resultata frå analysar av pressrest og olje frå camelina (Camilina sativa L. Borowska). Resultata viste at nitrogengjødsling auka innhaldet av omega-3 feittsyra alfa-linolensyre (18:3) og innhaldet av tokoferol (Vitamin E) i oljen. Det var ingen effekt av svovelgjødsling eller interaksjonar mellom nitrogen og svovelgjødslinga på oljeinnhaldet. Nitrogengjødsling om våren auka svovelinnhaldet og reduserte innhaldet av kalsium og fosfor i pressresten. Det ser ikkje ut til at gjødsling med svovel har nokon stor verknad på det kjemisk innhaldet i camelina, men svovelinnhaldet i camelina er høgt samanlikna med tabellverdi og dei andre oljevekstane i gjødslingsforsøket. Elles ser det ikkje ut til å være store forskjellane frå dei andre økologiske oljevekstane. Resultata viser at camelina er godt egna for økologisk dyrking og at innhaldet av næringskomponent blir påverka av vekstsesong og nitrogengjødsling. Likevel er variasjonen i næringsinnhald liten.
Forfattere
Yehia Sayed El-temsah Alena Sevcu Erik Joner Miroslav CernikSammendrag
Nanoscale zero-valent iron particles (nZVI), with sizes smaller than 100 nm, are promising for environmental remediation of polluted water, soil and sediments. nZVI particles have high potential for migration in the environment and are likely to interact not only with pollutant chemicals but also with living organisms. For these reasons, an environmental concern is rising with respect to unintended effects that need to be weighed against the benefits of remediation. The nZVI particles have a tendency to release electrons and Fe2+. The Fe2+ can convert less reactive hydrogen peroxide to more reactive oxygen species, particularly hydroxyl radicals, via the Fenton reaction. Hydroxyl radicals show strong biochemical activity and can react directly with membrane lipids, proteins and DNA. Reactive oxygen species are normally scavenged by antioxidants and various enzymes; however, elevated concentrations of ROS in microbial cells can result in oxidative stress. Cells under severe oxidative stress show various dysfunctions of membrane lipids, proteins and DNA. This review focuses on the processes resulting in oxidative stress and on up-to-date studies of nZVI-induced intracellular changes leading to such stress in microorganisms.
Sammendrag
The appearance of new problems caused by Phytophthora species has triggered a number of sanitary surveillances and surveys in nurseries, parks and ornamental production fields in Norway the last 8 years. As a result, several Phytophthora species and new hosts for already known species have been detected in Norway. On woody plants of ornamental value we have found: P. cactorum, P. citricola (plurivora), P. cambivora, P. citrophthora, P. gonopodyides, P. inundata-like, P. megasperma complex, P. ramorum and P. syringae. P. cinnamomi has been found in potted plants in nurseries and in greenhouses, but never in established plants. P. taxon Pgchlamydo was isolated from the soil and debris of an ornamental nursery. In fruit and berry production we have found: P. cactorum, P. cryptogea, P. fragariae, P. megasperma complex and P. rubi. Other Phytopthtora species, reported to cause damages on trees or scrubs, have been detected only in greenhouses in Norway: P. nicotianae, P. taxon niederhauserii and P. palmivora. Until the 2000s the identifications of Phytophthora species were made by morphological characters. In the last years we always combined morphology with molecular methods for identification (mainly ITS or cox sequencing).