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.
2012
Abstract
No abstract has been registered
Authors
Belachew Asalf Tadesse Nina Trandem Arne Stensvand Vitalis Wekesa Gilberto J de Moraes Ingeborg KlingenAbstract
No abstract has been registered
Abstract
Fusarium langsethiae is a recently characterized fungus within the genus Fusarium. It is found as a grain contaminant of small grain cereals such as oats and barley, and to a lesser extent wheat. Fusarium langsethiae is particularly widespread in the Nordic countries and the UK where it poses a serious problem as the main producer of T-2 and HT-2 mycotoxins. The biology of F. langsethiae and its interaction with the plant remains poorly understood, partly hampered by difficulties reproducing a natural level of infection under controlled conditions. The reported study was designed as a series of glasshouse experiments to advance our understanding of F. langsethiae biology by investigating alternative infection routes and its proliferation in oats, Avena sativa. Various methods of seed, soil, and seedling inoculation, boot injection and spray inoculation, were tested. The results clearly show a strong preference of F. langsethiae for the panicle, ruling out alternative infection routes. At relatively low temperatures spray infection, accompanied by prolonged humidity, ensured a thorough establishment of the fungus both at flowering and at early dough stage. Boot injection proved to be a reliable working tool for production of an even and predictable grain infection. Apart from in the panicle, considerable fungal proliferation was only detected in flag leaf nodes, and was a direct consequence of the boot injection method. Fungal presence in the node tissue also correlated with significant stunting of infected shoots. In light of the results the pathogenic and endophytic abilities of F. langsethiae are discussed.
Abstract
In an attempt to find alternative products to classical fungicides, several products with low toxicity were tested against powdery mildew of roses. These products included resistance inducers (Bion, BABA, and ROS), potassium salts (Resistim, monopotassium phosphate), and seed extracts. The best results were obtained with acibenzolar-S-methyl (Bion). The utilization of Bion as prophylactic treatment, watered at a concentration 0.1–0.2 mg/ml, together with good cultural practices can be enough to effectively control powdery mildew on roses. Treatments with Resistim reduced the disease incidence, but not always significantly compared to the controls. None of the other products had effect on powdery mildew.
Authors
Åke Olson Andrea Aerts Fred Asiegbu Lassaad Belbahri Ourdia Bouzid Anders Broberg Björn Canback Pedro M. Coutinho Dan Cullen Kerstin Dalman Giuliana Deflorio Linda T.A. van Diepen Christophe Dunand Sébastien Duplessis Mikael Durling Paolo Gonthier Jane Grimwood Carl Gunnar Fossdal David Hansson Bernard Henrissat Ari Hietala Kajsa Himmelstrand Dirk Hoffmeister Nils Högberg Timothy Y. James Magnus Karlsson Annegret Kohler Ursula Kües Yong-Hwan Lee Yao-Cheng Lin Mårten Lind Erika Lindquist Vincent Lombard Susan Lucas Karl Lundén Emmanuelle Morin Claude Murat Jongsun Park Tommaso Raffaello Pierre Rouzé Asaf Salamov Jeremy Schmutz Halvor Solheim Jerry Ståhlberg Heriberto Vélëz Ronald P. de Vries Ad Wiebenga Steve Woodward Igor A. Yakovlev Matteo Garbelotto Francis Martin Igor V. Grigoriev Jan StenlidAbstract
• Parasitism and saprotrophic wood decay are two fungal strategies fundamental for succession and nutrient cycling in forest ecosystems. An opportunity to assess the trade-off between these strategies is provided by the forest pathogen and wood decayer Heterobasidion annosum sensu lato. • We report the annotated genome sequence and transcript profiling, as well as the quantitative trait loci mapping, of one member of the species complex: H. irregulare. Quantitative trait loci critical for pathogenicity, and rich in transposable elements, orphan and secreted genes, were identified. • A wide range of cellulose-degrading enzymes are expressed during wood decay. By contrast, pathogenic interaction between H. irregulare and pine engages fewer carbohydrate-active enzymes, but involves an increase in pectinolytic enzymes, transcription modules for oxidative stress and secondary metabolite production. • Our results show a trade-off in terms of constrained carbohydrate decomposition and membrane transport capacity during interaction with living hosts. Our findings establish that saprotrophic wood decay and necrotrophic parasitism involve two distinct, yet overlapping, processes.
Authors
Aruppillai Suthaparan Sissel Torre Leiv M. Mortensen Hans Ragnar Gislerød Knut Asbjørn Solhaug Arne Stensvand David M. GadouryAbstract
No abstract has been registered
Authors
Igor A. Yakovlev Gustav Vaaje-Kolstad Ari Hietala Emil Stefanczyk Halvor Solheim Carl Gunnar FossdalAbstract
No abstract has been registered
Authors
Nina Elisabeth Nagy Harald Kvaalen Monica Fongen Carl Gunnar Fossdal Nicholas Clarke Halvor Solheim Ari HietalaAbstract
Pathogen challenge of tree sapwood induces the formation of reaction zones with antimicrobial properties such as elevated pH and cation content. Many fungi lower substrate pH by secreting oxalic acid, its conjugate base oxalate being a reductant as well as a chelating agent for cations. To examine the role of oxalic acid in pathogenicity of white-rot fungi, we conducted spatial quantification of oxalate, transcript levels of related fungal genes, and element concentrations in heartwood of Norway spruce challenged naturally by Heterobasidion parviporum. In the pathogen-compromised reaction zone, upregulation of an oxaloacetase gene generating oxalic acid coincided with oxalate and cation accumulation and presence of calcium oxalate crystals. The colonized inner heartwood showed trace amounts of oxalate. Moreover, fungal exposure to the reaction zone under laboratory conditions induced oxaloacetase and oxalate accumulation, whereas heartwood induced a decarboxylase gene involved in degradation of oxalate. The excess level of cations in defense xylem inactivates pathogen-secreted oxalate through precipitation and, presumably, only after cation neutralization can oxalic acid participate in lignocellulose degradation. This necessitates enhanced production of oxalic acid by H. parviporum. This study is the first to determine the true influence of white-rot fungi on oxalate crystal formation in tree xylem.
Abstract
No abstract has been registered
Abstract
No abstract has been registered