Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nur... more Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nursery-grown conifer seedlings, were fruited in the laboratory and the pairing interactions among sibling, single-basidiospore progeny were investigated. No mating reactions were observed. Instead, a high frequency of somatic incompatibility was observed in progeny pairings, indicated by a killing reaction in hyphal anastomosis and by formation of a demarcation line. The F1 progeny also could be fruited, and the level of somatic incompatibility within the F2 progeny remained high, even if lower than in the F1 progeny. The interaction types in pairings within a family of progeny were similar in all respects to those between field isolates, indicating that the species is homothallic. The uninucleate condition of vegetative cells and the basidial characteristics would indicate homokaryotic fruiting, but the possibility of pseudohomothallism remains. We currently are not able to provide an exp...
The difficulty in sub-culturing biotrophic fungi complica- tes etiological studies related to the... more The difficulty in sub-culturing biotrophic fungi complica- tes etiological studies related to the associated plant disea- ses. By employing species-specific ITS sequence stret- ches, we used real-time PCR to investigate the spatial colo- nization profiles of T. areolata and a co-existing Phomopsis species in seedlings and saplings of Norway spruce showing bark necrosis. There was a strong gradient in the
In spring 2002, an unusual disease outburst was recorded on Norway spruce seedlings in southeast ... more In spring 2002, an unusual disease outburst was recorded on Norway spruce seedlings in southeast Norway. Extensive damage was recorded on 1- and 2-year-old Norway spruce seedlings that either had wintered in nursery cold storage or had been planted out in autumn 2001. The damage was characterized by leader shoot dieback and stem necroses on the upper or lower part of the shoot from 2001. Gremmeniella abietina and a Phomopsis sp. frequently were isolated from the diseased seedlings. Internal transcribed spacer (ITS) ribosomal (r)DNA sequence analysis and random amplified microsatellites profiling indicated that the G. abietina strains associated with diseased nursery seedlings belonged to the large-tree type (LTT) ecotype of the European race of G. abietina var. abietina, and inoculation tests confirmed their pathogenicity on Norway spruce. Based on ITS rDNA sequence analysis, the Phomopsis strains associated with diseased seedlings did not represent any characterized Phomopsis spp. ...
We studied the defense reactions of 33-year-old susceptible and resistant clones of Norway spruce... more We studied the defense reactions of 33-year-old susceptible and resistant clones of Norway spruce (Picea abies (L.) Karst.) to the major root-rot fungus Heterobasidion annosum (Fr.) Bref. and determined if tissue cultures can be used as a model system for studying defense responses of mature trees at the molecular level. Quantitative PCR analysis of genomic DNA obtained from samples taken at different times along the lesion length in living bark indicated that the fungus was present in higher amounts and extended further into the host tissue in the susceptible clone than in the resistant clone. In protein extracts from the same lesion samples, there were differences in temporal and spatial changes in host chitinase isoform profiles between the resistant and susceptible clones. Host chitinase isoforms with pI values approximately 4.8, 4.4 and 3.7 increased more during the first 7 days after wounding and inoculation and extended further along the lesion length in the resistant clone t...
Pathogen colonization and transcript levels of three host chitinases, putatively representing cla... more Pathogen colonization and transcript levels of three host chitinases, putatively representing classes I, II, and IV, were monitored with real-time PCR after wounding and bark infection by Heterobasidion annosum in 32-year-old trees of Norway spruce (Picea abies) with low (clone 409) or high (clone 589) resistance to this pathogen. Three days after inoculation, comparable colonization levels were observed in both
In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce ... more In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce seed- lings that had either wintered in nursery cold storage or had been planted out in autumn 2001. The damage was charac- terised by a top shoot dieback. Two visually distinct types of necroses were located either on the upper or lower part of the 2001-year-shoot.
Abstract This paper describes the use of quantitative real-time PCR for monitoring colonization o... more Abstract This paper describes the use of quantitative real-time PCR for monitoring colonization of birch wood (Betula pubescens) by the white-rot fungus Trametes versicolor in an EN113 decay experiment. The wood samples were harvested after 4, 8, 12, 16 and 20 weeks of incubation. The mass loss was in the range of 4â40%. Chitin and ergosterol assays were conducted for comparison. Second-order polynomial fits of the mass loss of decayed wood versus chitin, ergosterol and DNA gave correlations (r 2) of 0.87, 0.61 and ...
Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nur... more Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nursery-grown conifer seedlings, were fruited in the laboratory and the pairing interactions among sibling, single-basidiospore progeny were investigated. No mating reactions were observed. Instead, a high frequency of somatic incompatibility was observed in progeny pairings, indicated by a killing reaction in hyphal anastomosis and by formation of a demarcation line. The F1 progeny also could be fruited, and the level of somatic incompatibility within the F2 progeny remained high, even if lower than in the F1 progeny. The interaction types in pairings within a family of progeny were similar in all respects to those between field isolates, indicating that the species is homothallic. The uninucleate condition of vegetative cells and the basidial characteristics would indicate homokaryotic fruiting, but the possibility of pseudohomothallism remains. We currently are not able to provide an exp...
The difficulty in sub-culturing biotrophic fungi complica- tes etiological studies related to the... more The difficulty in sub-culturing biotrophic fungi complica- tes etiological studies related to the associated plant disea- ses. By employing species-specific ITS sequence stret- ches, we used real-time PCR to investigate the spatial colo- nization profiles of T. areolata and a co-existing Phomopsis species in seedlings and saplings of Norway spruce showing bark necrosis. There was a strong gradient in the
In spring 2002, an unusual disease outburst was recorded on Norway spruce seedlings in southeast ... more In spring 2002, an unusual disease outburst was recorded on Norway spruce seedlings in southeast Norway. Extensive damage was recorded on 1- and 2-year-old Norway spruce seedlings that either had wintered in nursery cold storage or had been planted out in autumn 2001. The damage was characterized by leader shoot dieback and stem necroses on the upper or lower part of the shoot from 2001. Gremmeniella abietina and a Phomopsis sp. frequently were isolated from the diseased seedlings. Internal transcribed spacer (ITS) ribosomal (r)DNA sequence analysis and random amplified microsatellites profiling indicated that the G. abietina strains associated with diseased nursery seedlings belonged to the large-tree type (LTT) ecotype of the European race of G. abietina var. abietina, and inoculation tests confirmed their pathogenicity on Norway spruce. Based on ITS rDNA sequence analysis, the Phomopsis strains associated with diseased seedlings did not represent any characterized Phomopsis spp. ...
We studied the defense reactions of 33-year-old susceptible and resistant clones of Norway spruce... more We studied the defense reactions of 33-year-old susceptible and resistant clones of Norway spruce (Picea abies (L.) Karst.) to the major root-rot fungus Heterobasidion annosum (Fr.) Bref. and determined if tissue cultures can be used as a model system for studying defense responses of mature trees at the molecular level. Quantitative PCR analysis of genomic DNA obtained from samples taken at different times along the lesion length in living bark indicated that the fungus was present in higher amounts and extended further into the host tissue in the susceptible clone than in the resistant clone. In protein extracts from the same lesion samples, there were differences in temporal and spatial changes in host chitinase isoform profiles between the resistant and susceptible clones. Host chitinase isoforms with pI values approximately 4.8, 4.4 and 3.7 increased more during the first 7 days after wounding and inoculation and extended further along the lesion length in the resistant clone t...
Pathogen colonization and transcript levels of three host chitinases, putatively representing cla... more Pathogen colonization and transcript levels of three host chitinases, putatively representing classes I, II, and IV, were monitored with real-time PCR after wounding and bark infection by Heterobasidion annosum in 32-year-old trees of Norway spruce (Picea abies) with low (clone 409) or high (clone 589) resistance to this pathogen. Three days after inoculation, comparable colonization levels were observed in both
In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce ... more In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce seed- lings that had either wintered in nursery cold storage or had been planted out in autumn 2001. The damage was charac- terised by a top shoot dieback. Two visually distinct types of necroses were located either on the upper or lower part of the 2001-year-shoot.
Abstract This paper describes the use of quantitative real-time PCR for monitoring colonization o... more Abstract This paper describes the use of quantitative real-time PCR for monitoring colonization of birch wood (Betula pubescens) by the white-rot fungus Trametes versicolor in an EN113 decay experiment. The wood samples were harvested after 4, 8, 12, 16 and 20 weeks of incubation. The mass loss was in the range of 4â40%. Chitin and ergosterol assays were conducted for comparison. Second-order polynomial fits of the mass loss of decayed wood versus chitin, ergosterol and DNA gave correlations (r 2) of 0.87, 0.61 and ...
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