| 1. |
|
|
| 2. |
|
|
| 3. |
- Adomas, Aleksandra, et al.
(författare)
-
Comparative analysis of transcript abundance in Pinus sylvestris after challenge with a saprotrophic, pathogenic or mutualistic fungus
- 2008
-
Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 28:6, s. 885-897
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate functional differences in the recognition and response mechanisms of conifer roots to fungi with different trophic strategies, Pinus sylvestris L. was challenged with a saprotrophic fungus Trichoderma aureoviride Rifai. The results were compared with separate studies investigating pine interactions with a pathogen, Heterobasidion annosum (Fr.) Bref. sensu stricto and an ectomycorrhizal symbiont, Laccaria bicolor Maire (Orton). Global changes in the expression of 2109 conifer genes were assayed 1, 5 and 15 days after inoculation. Gene expression data from a cDNA microarray were analyzed by the 2-interconnected mixed linear model statistical approach. The total number of genes differentially expressed compared with the uninfected control was similar after challenge with the pathogen and the ectomycorrhizal symbiont, but the number of differentially expressed genes increased over time, for H. annosum, and decreased for L. bicolor. Inoculation of pine roots with T aureoviride resulted overall in a much lower number of genes with changed transcript levels compared with inoculation with H. annosum or L. bicolor. Functional classification of the differentially expressed genes revealed that the ectomycorrhizal fungus triggered transient induction of defence-related genes. The response and induction of defence against the pathogen was delayed and the magnitude increased over time. Thus, there were specific transcriptional responses depending on whether the conifer roots were challenged with mutualistic, saprotrophic or pathogenic fungi. This suggests that pine trees are able to recognize diverse fungal species and specifically distinguish whether they are pathogenic, neutral or beneficial microbial agents.
|
|
| 4. |
- Andersson, Ulrika, et al.
(författare)
-
Germline rearrangements in families with strong family history of glioma and malignant melanoma, colon, and breast cancer
- 2014
-
Ingår i: Neuro-Oncology. - : Oxford University Press. - 1522-8517 .- 1523-5866. ; 16:10, s. 1333-1340
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Although familial susceptibility to glioma is known, the genetic basis for this susceptibility remains unidentified in the majority of glioma-specific families. An alternative approach to identifying such genes is to examine cancer pedigrees, which include glioma as one of several cancer phenotypes, to determine whether common chromosomal modifications might account for the familial aggregation of glioma and other cancers. Methods: Germline rearrangements in 146 glioma families (from the Gliogene Consortium; http://www.gliogene.org/) were examined using multiplex ligation-dependent probe amplification. These families all had at least 2 verified glioma cases and a third reported or verified glioma case in the same family or 2 glioma cases in the family with at least one family member affected with melanoma, colon, or breast cancer. The genomic areas covering TP53, CDKN2A, MLH1, and MSH2 were selected because these genes have been previously reported to be associated with cancer pedigrees known to include glioma. Results: We detected a single structural rearrangement, a deletion of exons 1-6 in MSH2, in the proband of one family with 3 cases with glioma and one relative with colon cancer. Conclusions: Large deletions and duplications are rare events in familial glioma cases, even in families with a strong family history of cancers that may be involved in known cancer syndromes.
|
|
| 5. |
- Arnerup, Jenny, et al.
(författare)
-
The pathogenic white-rot fungus Heterobasidion parviporum triggers non-specific defence responses in the bark of Norway spruce
- 2011
-
Ingår i: Tree Physiology. - : Oxford University Press. - 0829-318X .- 1758-4469. ; 31:11, s. 1262-1272
-
Tidskriftsartikel (refereegranskat)abstract
- Norway spruce [Picea abies (L.) Karst.] is one of the economically most important conifer species in Europe. The major pathogen on Norway spruce is Heterobasidion parviporum (Fr.) Niemelä & Korhonen. To achieve a better understanding of Norway spruce's defence mechanisms, transcriptional responses in bark to H. parviporum infection were compared with the response to wounding using cDNA-amplified fragment length polymorphism. The majority of the recovered transcript-derived fragments (TDFs) showed a similar expression pattern for infection and wounding treatment, although inoculated samples showed an enhanced reaction. Genes related to systemic acquired resistance, e.g., PR1, accumulated after H. parviporum infection. Simultaneously, several transcripts involved in various aspects of jasmonic acid (JA)- and ethylene (ET)-mediated signalling accumulated. Genes involved in the ubiquitin/proteasome system were also regulated. Expression patterns have been confirmed by quantitative polymerase chain reaction. The expression patterns of the isolated TDFs suggest that infection with H. parviporum in Norway spruce induces a broad defence, with many similarities to non-specific defence responses in angiosperms. The parallel induction of salicylic acid- and JA/ET-mediated pathways implies spatially separated responses in different cell layers, with and without hyphal contact. A set of TDFs were analysed in an independent experiment with unrelated material treated with wounding or with inoculation with H. parviporum or Phlebiopsis gigantea, verifying the original observations and underlining the non-specific defence responses. In addition, our data suggest that rerouting of carbon in secondary metabolism is an integral part of Norway spruce induced defence. We report the sequences of three 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase genes (PaDAHP1, PaDAHP2 and PaDAHP3) and their relative expression in response to wounding and infection with H. parviporum and P. gigantea. The results clearly indicate differential regulation of the three DAHPs in the induced defence responses in Norway spruce. This study gives insights into the central mechanisms in the induced defences in Norway spruce.
|
|
| 6. |
- Berlin, Anna, et al.
(författare)
-
Scientific evidence for sustainable plant disease protection strategies for the main arable crops in Sweden. A systematic map protocol
- 2018
-
Ingår i: Environmental Evidence. - : Springer Science and Business Media LLC. - 2047-2382. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Efficient and sustainable plant protection is of great economic and ecological significance for global crop production. A number of challenges, e.g. climate change, population growth and global trade, put increasing demands on future crop production and crop protection. This necessitates an increase in crop productivity with less environmental impact while maintaining good food quality and food security. To meet these challenges, it is essential that the recommendations provided to growers are efficient and correct, which can only be ensured by evidence-based recommendations based on outcomes from scientific studies.Methods and output: The aim of these systematic maps is to compile scientific evidence for different plant disease protection strategies for the main arable crops grown in Sweden. Six major crops (wheat, barley, oat, potato, sugar beet and oilseed rape) have been selected based on the area under production, the annual production, the economic importance, and the amount of pesticide used against diseases in these crops in Sweden. All methods to manage diseases will be considered, including cropping system, pesticide application, biological control methods, as well as combinations of methods and integrated pest management. These systematic maps will only deal with field studies of relevance for agricultural practices in Sweden, although we expect that the results will be applicable for northern Europe as a whole. The main outcome to be used will be productivity measured as yield per area. Plant health and pathogen reduction will be included as a proxy for potential increase in crop quality and yield. This will provide a systematic overview of the plant disease protection measures that have been reported in the scientific literature. The study will result in one searchable database per crop that may be used as a catalogue of evidence for researchers and stakeholders, especially authorities and advisory organizations. The systematic maps will aid in the identification of areas that need further research and guide funding agencies and policymakers when deciding where research resources should be allocated. It will also help to select topics for future systematic reviews and meta-studies within the field of plant protection.
|
|
| 7. |
- Borg, Åke, et al.
(författare)
-
Characterization of BRCA1 and BRCA2 deleterious mutations and variants of unknown clinical significance in unilateral and bilateral breast cancer: the WECARE study.
- 2010
-
Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 31, s. 1200-1240
-
Tidskriftsartikel (refereegranskat)abstract
- BRCA1 and BRCA2 screening in women at high-risk of breast cancer results in the identification of both unambiguously defined deleterious mutations and sequence variants of unknown clinical significance (VUS). We examined a population-based sample of young women with contralateral breast cancer (CBC, n=705) or unilateral breast cancer (UBC, n=1398). We identified 470 unique sequence variants, of which 113 were deleterious mutations. The remaining 357 VUS comprised 185 unique missense changes, 60% were observed only once, while 3% occurred with a frequency of >10%. Deleterious mutations occurred three times more often in women with CBC (15.3%) than in women with UBC (5.2%), whereas combined, VUS were observed in similar frequencies in women with CBC and UBC. A protein alignment algorithm defined 16 rare VUS, occurring at highly conserved residues and/or conferring a considerable biochemical difference, the majority located in the BRCA2 DNA-binding domain. We confirm a multiplicity of BRCA1 and BRCA2 VUS that occur at a wide range of allele frequencies. Although some VUS inflict chemical differences at conserved residues, suggesting a deleterious effect, the majority are not associated with an increased risk of CBC. (c) 2010 Wiley-Liss, Inc.
|
|
| 8. |
- Bödeker, Inga, et al.
(författare)
-
ClassII peroxidase-encoding genes are present in a phylogenetically wide range of ectomycorrhizal fungi
- 2009
-
Ingår i: ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 3, s. 1387-1395
-
Tidskriftsartikel (refereegranskat)abstract
- Fungal peroxidases (ClassII) have a key role in degrading recalcitrant polyphenolic compounds in boreal forest wood, litter and humus. To date, their occurrence and activity have mainly been studied in a small number of white-rot wood decomposers. However, peroxidase activity is commonly measured in boreal forest humus and mineral soils, in which ectomycorrhizal fungi predominate. Here, we used degenerate PCR primers to investigate whether peroxidase-encoding genes are present in the genomes of a wide phylogenetic range of ectomycorrhizal taxa. Cloning and sequencing of PCR products showed that ectomycorrhizal fungi from several different genera possess peroxidase genes. The new sequences represent four major homobasidiomycete lineages, but the majority is derived from Cortinarius, Russula and Lactarius. These genera are ecologically important, but consist mainly of non-culturable species from which little ecophysiological information is available. The amplified sequences contain conserved active sites, both for folding and substrate oxidation. In some Cortinarius spp., there is evidence for gene duplications during the evolution of the genus. ClassII peroxidases seem to be an ancient and a common feature of most homobasidiomycetes, including ectomycorrhizal fungi. Production of extracellular peroxidases may provide ectomycorrhizal fungi with access to nitrogen sequestered in complex polyphenolic sources. The ISME Journal (2009) 3, 1387-1395; doi: 10.1038/ismej.2009.77; published online 2 July 2009
|
|
| 9. |
- Bödeker, Inga, et al.
(författare)
-
Ectomycorrhizal Cortinarius species participate in enzymatic oxidation of humus in northern forest ecosystems
- 2014
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 203, s. 245-256
-
Tidskriftsartikel (refereegranskat)abstract
- In northern forests, belowground sequestration of nitrogen (N) in complex organic pools restricts nutrient availability to plants. Oxidative extracellular enzymes produced by ectomycorrhizal fungi may aid plant N acquisition by providing access to N in macromolecular complexes. We test the hypotheses that ectomycorrhizal Cortinarius species produce Mn-dependent peroxidases, and that the activity of these enzymes declines at elevated concentrations of inorganic N.In a boreal pine forest and a sub-arctic birch forest, Cortinarius DNA was assessed by 454-sequencing of ITS amplicons and related to Mn-peroxidase activity in humus samples with- and without previous N amendment. Transcription of Cortinarius Mn-peroxidase genes was investigated in field samples. Phylogenetic analyses of Cortinarius peroxidase amplicons and genome sequences were performed.We found a significant co-localization of high peroxidase activity and DNA from Cortinarius species. Peroxidase activity was reduced by high ammonium concentrations. Amplification of mRNA sequences indicated transcription of Cortinarius Mn-peroxidase genes under field conditions. The Cortinarius glaucopus genome encodes 11 peroxidases - a number comparable to many white-rot wood decomposers.These results support the hypothesis that some ectomycorrhizal fungi - Cortinarius species in particular - may play an important role in decomposition of complex organic matter, linked to their mobilization of organically bound N.
|
|
| 10. |
- Bödeker, Inga, et al.
(författare)
-
Mycorrhizal and saprotrophic fungal guilds compete for the same organic substrates but affect decomposition differently
- 2016
-
Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 30, s. 1967-1978
-
Tidskriftsartikel (refereegranskat)abstract
- 1. Communities of litter saprotrophic and root-associated fungi are vertically separated within boreal forest soil profiles. It is unclear whether this depth partitioning is maintained exclusively by substrate-mediated niche partitioning (i.e. distinct fundamental niches), or by competition for space and resources (i.e. distinct realized niches). Improved understanding of the mechanisms driving spatial partitioning of these fungal guilds is critical, as they modulate carbon and nutrient cycling in different ways.2. Under field settings, we tested the effects of substrate quality and the local fungal species pool at various depths in determining the potential of saprotrophic and mycorrhizal fungi to colonize and exploit organic matter. Natural substrates of three qualities-fresh or partly decomposed litter or humus -were incubated in the corresponding organic layers of a boreal forest soil profile in a fully factorial design. After one and two growing seasons, fungal community composition in the substrates was determined by 454-pyrosequencing and decomposition was analyzed.3. Fungal community development during the course of the experiment was determined to similar degrees by vertical location of the substrates (24% of explained variation) and by substrate quality (20%), indicating that interference competition is a strong additional driver of the substrate-dependent depth partitioning of fungal guilds in the system. During the first growing season, litter substrates decomposed slower when colonized by root-associated communities than when colonized by communities of litter saprotrophs, whereas humus was only slightly decomposed by both fungal guilds. During the second season, certain basidiomycetes from both guilds were particularly efficient in localizing and exploiting their native organic substrates although displaced in the vertical profile. This validates that fungal community composition, rather than microclimatic factors, were responsible for observed depth-related differences in decomposer activities during the first season.4. In conclusion, our results suggest that saprotrophic and root-associated fungal guilds have overlapping fundamental niches with respect to colonization of substrates of different qualities, and that their substrate-dependent depth partitioning in soils of ectomycorrhiza-dominated ecosystems is reinforced by interference competition. Through competitive interactions, mycorrhizal fungi can thus indirectly regulate litter decomposition rates by restraining activities of more efficient litter saprotrophs.
|
|
