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.
2008
Sammendrag
An infectious cDNA clone of a Norwegian isolate of Poinsettia mosaic virus (PnMV) was generated. It consisted of 6,098 nucleotides and encoded a polyprotein of 219.5 kDa. Sequence comparisons indicated that this isolate shared 98.6% (nucleotide) and 97.1% (amino acid) identity with the previously sequenced isolate from Germany. RNA transcripts derived from this cDNA were infectious in Nicotiana benthamiana. However, plants did not present typical PnMV symptoms. Furthermore, RNA transcripts from this cDNA clone were not infectious in poinsettia. Serial propagation of this cDNA clone in N. benthamiana plants restored symptom induction in this host but did not re-establish infectivity in poinsettia.
Forfattere
Abdelhameed Elameen Siri Fjellheim Arild Larsen Odd Arne Rognli Leif Sundheim Susan Msolla Esther Masumba Kiddo Mtunda Sonja KlemsdalSammendrag
Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania.
Forfattere
I. A. Yakolev Daniel Kwaku Addo Asante Carl Gunnar Fossdal Jouni Partanen Olavi Junttila Øystein JohnsenSammendrag
Det er ikke registrert sammendrag
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Det er ikke registrert sammendrag
Sammendrag
The difficulty in subculturing biotrophic fungi complicates etiological studies related to the associated plant diseases. By employing internal transcribed spacer rDNA-targeted quantitative real-time polymerase chain reaction, we now show that the heteroecious rust Thekopsora areolata, commonly associated in natural conditions to sapling shoots and cones of Norway spruce and leaves of wild bird cherry, frequently infects nurserygrown seedlings of the conifer. A spatial sampling scheme was used to investigate seedlings and saplings of Norway spruce showing phloem necrosis: the highest concentration of DNA of T. areolata was recorded in the area with necrotic phloem. The separate analysis of bark and wood tissues suggested that the initial spread of the rust to healthy tissues neighboring the infection site takes place in the bark. A Phomopsis species found to coexist with T. areolata in several seedlings showed very high DNA levels in the upper part of the lesion, and even in the visually healthy proximal tissues above the lesions, which indicates that the ascomycete, most probably a secondary invader following primary infection by T. areolata, has a latent stage during early host colonization. We hypothesize that this hemibiotrophic mode of infection contributes to the successful coexistence of Phomopsis with a biotrophic rust.
Sammendrag
Many bacteria produce antimicrobial substances such as nonribosomally synthesized antibiotics and ribosomally synthesized proteinaceous compounds referred to as bacteriocins. Secretion of antimicrobials is generally thought to contribute to the competitiveness of the producing organism, but there are indications that these compounds in some cases may have regulatory roles too. Bacteriocins most often act on closely related species only and are thus of interest for application as targeted narrow-spectrum antimicrobials with few side effects. Although the application of bacteriocins in plant disease control is an attractive option, very little is known about the occurrence and roles of these compounds in plant pathogenic bacteria and their natural competitors occurring in the same biotopes. This study presents an overview of current knowledge of bacteriocins from plant pathogenic bacteria.
Sammendrag
Jorda er bosted for et utallig antall former for planter, dyr og mikrober. Disse varierer fra mikroskopiske encellede organismer til store gravende dyr. Tilsvarende som for overjordiske miljøer, er det godt definerte næringskjeder og konkurranse om overlevelse i jordmiljøet. Ulike samspill i jordøkosystemet kan både fremme og redusere forekomsten av skadedyr (insekter og midd) som er tilknyttet jord. Skadedyr tilknyttet jorda har derfor også naturlige fiender blant jordorganismene, men også skadedyr som bare tilfeldigvis kommer i kontakt med jorda, ved at de for eksempel ramler ned fra planta de lever på, kan bli spist av predatorer ("rovdyr") eller bli infisert av mikroorganismer som finnes på jorda.
Sammendrag
Undersøkingar av koloradoedelgran på Vest- og Austlandet i 2008 tydar på at kreftsoppen Nectria sp. er svært aggressiv på denne edelgranarten. Det vert planta relativt lite koloradoedelgran, så som regel finn ein berre solitære tre i nokre få hagar og grøntanlegg. Meir urovekkjande er det at vi i 2008 også fann store skadar på grunn av Nectria sp. på fjelledelgran i Nordskogen på Ås, då det vert satsa stort på denne trearten i norsk juletredyrking.
Forfattere
Venche Talgø Iben Margrete Thomsen Thomas Cech Gary Chastagner Kathy Riley Kurt Lange Sonja Klemsdal Arne StensvandSammendrag
Forsøg med at smitte nordmannsgran med svampen Kabatina abietis førte til pletter på årsskuddenes nåle. Dette kunne tyde på, at svampen er årsag til CSNN eller "røde nåle".
Sammendrag
Det er ikke registrert sammendrag