| 1. |
- Harsanyi, Anett, et al.
(författare)
-
Alterations of NADPH:protochlorophyllide oxidoreductase quantity and lipid composition in etiolated barley seedlings infected by Barley stripe mosaic virus (BSMV)
- 2006
-
Ingår i: Molecular Plant Pathology. - : Wiley. - 1464-6722 .- 1364-3703. ; 7:6, s. 533-541
-
Tidskriftsartikel (refereegranskat)abstract
- To understand the phenomenon by which infection of seed-transmitted Barley stripe mosaic virus (BSMV) alters membrane structures and inhibits protochlorophyllide biosynthesis of dark-grown barley (Hordeum vulgare L.) plants, we analysed the presence of NADPH:protochlorophyllide oxidoreductase (POR, EC 1.3.1.33) and the galactolipid content and fatty acid composition. The amount of POR in etioplasts of infected leaves, compared with non-infected leaves, was reduced, as measured by immunoelectron microscopy and Western blot. These results are in agreement with the previously described reduction of the ratio of the photoactive 650 nm to non-photoactive 630 nm absorbing protochlorophyllide forms (Harsányi et al., 2002. Physiol. Plant 114, 149155). The galactolipid content was lower in infected leaves. Monogalactosyl-diacylglycerol (MGDG) content was reduced to 40% and digalactosyl-diacylglycerol to 55% of control plants on a fresh weight basis. In infected plants, the proportion of linolenic acid decreased in both galactolipids. The lower amount of highly unsaturated fatty acids and the reduced abundance of MGDG correlated well with the previously detected reduction in the membrane ratio of prolamellar body (PLB) to prothylakoid (Harsányi et al., 2002. Physiol. Plant 114, 149155). The reduced amount of POR and the above described alterations in the lipid composition resulted in a disturbed structure of PLBs. As a consequence, pigment synthesis and the greening process were inhibited in infected cells, in turn explaining the appearance of chlorotic stripes of BSMV-infected barley leaves. Our results show that BSMV infection can be detected at a very early stage of leaf development.
|
|
| 2. |
- Ryberg, Martin, 1976, et al.
(författare)
-
Mining metadata from unidentified ITS sequences in GenBank: a case study in Inocybe (Basidiomycota)
- 2008
-
Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 8:50
-
Tidskriftsartikel (refereegranskat)abstract
- Background The lack of reference sequences from well-identified mycorrhizal fungi often poses a challenge to the inference of taxonomic affiliation of sequences from environmental samples, and many environmental sequences are thus left unidentified. Such unidentified sequences belonging to the widely distributed ectomycorrhizal fungal genus Inocybe (Basidiomycota) were retrieved from GenBank and divided into species that were identified in a phylogenetic context using a reference dataset from an ongoing study of the genus. The sequence metadata of the unidentified Inocybe sequences stored in GenBank, as well as data from the corresponding original papers, were compiled and used to explore the ecology and distribution of the genus. In addition, the relative occurrence of Inocybe was contrasted to that of other mycorrhizal genera. Results Most species of Inocybe were found to have less than 3% intraspecific variability in the ITS2 region of the nuclear ribosomal DNA. This cut-off value was used jointly with phylogenetic analysis to delimit and identify unidentified Inocybe sequences to species level. A total of 177 unidentified Inocybe ITS sequences corresponding to 98 species were recovered, 32% of which were successfully identified to species level in this study. These sequences account for an unexpectedly large proportion of the publicly available unidentified fungal ITS sequences when compared with other mycorrhizal genera. Eight Inocybe species were reported from multiple hosts and some even from hosts forming arbutoid or orchid mycorrhizae. Furthermore, Inocybe sequences have been reported from four continents and in climate zones ranging from cold temperate to equatorial climate. Out of the 19 species found in more than one study, six were found in both Europe and North America and one was found in both Europe and Japan, indicating that at least many north temperate species have a wide distribution. Conclusions Although DNA-based species identification and circumscription are associated with practical and conceptual difficulties, they also offer new possibilities and avenues for research. Metadata assembly holds great potential to synthesize valuable information from community studies for use in a species and taxonomy-oriented framework.
|
|
