| 1. |
- Alexandersson, Erik, et al.
(author)
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Tro får inte ersätta vetenskap
- 2014
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In: Svenska dagbladet. - 1101-2412.
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Journal article (pop. science, debate, etc.)
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| 2. |
- Andersson, Mariette
(author)
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Comparative Transcriptome Analysis of Three Oil Palm Fruit and Seed Tissues That Differ in Oil Content and Fatty Acid Composition
- 2013
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In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 162, s. 1337-1358
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Journal article (peer-reviewed)abstract
- Oil palm (Elaeis guineensis) produces two oils of major economic importance, commonly referred to as palm oil and palm kernel oil, extracted from the mesocarp and the endosperm, respectively. While lauric acid predominates in endosperm oil, the major fatty acids (FAs) of mesocarp oil are palmitic and oleic acids. The oil palm embryo also stores oil, which contains a significant proportion of linoleic acid. In addition, the three tissues display high variation for oil content at maturity. To gain insight into the mechanisms that govern such differences in oil content and FA composition, tissue transcriptome and lipid composition were compared during development. The contribution of the cytosolic and plastidial glycolytic routes differed markedly between the mesocarp and seed tissues, but transcriptional patterns of genes involved in the conversion of sucrose to pyruvate were not related to variations for oil content. Accumulation of lauric acid relied on the dramatic up-regulation of a specialized acyl-acyl carrier protein thioesterase paralog and the concerted recruitment of specific isoforms of triacylglycerol assembly enzymes. Three paralogs of the WRINKLED1 (WRI1) transcription factor were identified, of which EgWRI1-1 and EgWRI1-2 were massively transcribed during oil deposition in the mesocarp and the endosperm, respectively. None of the three WRI1 paralogs were detected in the embryo. The transcription level of FA synthesis genes correlated with the amount of WRI1 transcripts and oil content. Changes in triacylglycerol content and FA composition of Nicotiana benthamiana leaves infiltrated with various combinations of WRI1 and FatB paralogs from oil palm validated functions inferred from transcriptome analysis.
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| 3. |
- Arif, Usman
(author)
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Effect of wounding and light exposure on sterol, glycoalkaloid, and calystegine levels in potato plants (Solanum tuberosum L. group Tuberosum)
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Steroidal glycoalkaloids (SGA) are neurotoxic substances that are present in some members of the Solanaceae family, including crop species like potato (Solanum tuberosum L.) and tomato. The SGA level in the potato tuber is a genetic trait, but certain environmental factors such as wounding and light exposure can increase SGA levels several-fold, which may render tubers unsuitable for human consumption. There is little information about SGA biosynthesis. The sterol cholesterol is commonly regarded as a SGA precursor, but there is little evidence for this view. To increase our understanding of the SGA biosynthesis and its molecular regulation, a microarray screen was performed using tubers from two potato cultivars subjected to wound and light treatments. Along with an alteration of sterol and SGA levels, the treatments were associated with an up-regulation of a small set of genes in sterol and SGA metabolism, including a gene encoding for the sterol reductase DWF1. DWF1 genes were found in two differentially regulated subtypes; DWF1 and DWF1-like (DWF1-L). Alteration of DWF1 and DWF1-L expression in transgenic potato showed a role for these genes in sterol and SGA synthesis. Also up-regulated in the microarray study were three transaminase-like genes, and role of StTAM1 in SGA synthesis was investigated by overexpression in transgenic potato. This resulted in elevated SGA levels, indicating the presence of a transamination in SGA synthesis. The genetic variation and stress responsiveness in Swedish potato cultivars regarding SGA and calystegine alkaloids (CA) level was determined by subjecting tubers to wounding, light exposure and elevated temperature. Only light and wounding increased SGA levels, and variation in the response was observed among the cultivars. CA levels were not stress-regulated, indicating that SGA and CA synthesis are not interrelated. These results show that the SGA level in potato tubers are regulated by a concerted action of a small set of key genes acting at different steps in the sterol and SGA pathways. Results also demonstrate a genetic variation in stress responsiveness among Swedish potato cultivars, and have identified the most sensitive ones. Results could in the near future be used to improve post-harvest handling of potato cultivars.
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| 4. |
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| 5. |
- Desta, Zeratsion Abera, et al.
(author)
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Genomic selection: genome-wide prediction in plant improvement
- 2014
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In: Trends in Plant Science. - : Elsevier BV. - 1360-1385 .- 1878-4372. ; 19, s. 592–601-
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Research review (peer-reviewed)abstract
- Association analysis is used to measure relations between markers and quantitative trait loci (QTL). Their estimation ignores genes with small effects that trigger underpinning quantitative traits. By contrast, genomewide selection estimates marker effects across the whole genome on the target population based on a prediction model developed in the training population (TP). Whole-genome prediction models estimate all marker effects in all loci and capture small QTL effects. Here, we review several genomic selection (GS) models with respect to both the prediction accuracy and genetic gain from selection. Phenotypic selection or markerassisted breeding protocols can be replaced by selection, based on whole-genome predictions in which phenotyping updates the model to build up the prediction accuracy.
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| 6. |
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| 7. |
- Ghasemkhani, Marjan
(author)
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Genetic basis for resistance against fruit tree canker in apple
- 2012
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Reports (other academic/artistic)abstract
- Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker which is regarded as a serious economic problem in horticulture. This fungus causes notable damage to apple trees and it is very important in some regions, especially North western Europe, where it can result in death of spur shoots and branches. Although it occurs in a wide range of temperatures, it is associated with wet weather and climate has an important effect on the geographic distribution. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Also, spores produced on the infected wood can act as an infection source in the orchards. The fungus can therefore be introduced into new orchards with infected planting material from other orchards or tree nurseries. Chemical and mechanical control like spraying of fungicides, covering wounds with paint, and cutting out infected branches, do not prevent the occurrence of epidemics. Breeding cultivars with a high level of resistance towards canker would be of great help towards the avoidance of this disease. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported and no major genes have been identified. Therefore, apple genotypes with comparatively high levels of genetically determined partial resistance should be identified for use in apple breeding.
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| 8. |
- Hegay, Sergay
(author)
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Diversity of beans grown in Kyrgyzstan and marker-aided breeding for resistance to Bean common mosaic virus and anthracnose
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Common bean (Phaseolus vulgaris L.) is an important export crop in Kyrgyzstan since the end of the 20th century. Kyrgyzstan produces about 70,000 t of common beans per year, which provides jobs to 76% of the population in the Talas region. Information about genetic diversity of common beans helps to select appropriate genetic material to be used for breeding programs. Accessions originating from both Mesoamerican and Andean gene pools, including the main Kyrgyz common bean market types were analyzed using simple sequence repeats (SSR) and qualitative morphological traits. The similarity matrices generated from the molecular and morphological data were well correlated (r = 0.49**). The cluster analysis of both data sets grouped the accessions according to their gene pools of origin, where Mesoamerican accessions were more diverse than Andean accessions. Both SSR and qualitative morphological markers were suitable for assigning cultivars to their gene pools of origin. Furthermore, information about traits of interest for Kyrgyz farmers has been gained. We found that Bean common mosaic virus strain NL6 and anthracnose affect this crop and reduce its grain yield significantly in Kyrgyzstan. The susceptible Kyrgyz cultivars Ryabaya, Kytayanka and Lopatka were included as recurrent parents in a backcrossing breeding scheme for introducing host plant resistance to these diseases from donor cultivars. After the 4th backcross, seeds (color, shape, size) and pods (shape) were similar to the respective recurrent parent. The sequence characterized amplified region (SCAR) markers SW13, SBD5 and SCAreoli were used successfully in marker-aided backcrossing for pyramiding the I, bc-12 and Co-2 genes, which provide host plant resistance to BCMV and anthracnose, respectively. Inoculation tests with anthracnose races delta and gamma, virus strain NL3, and DNA markers confirmed the presence of resistance genes in the offspring.
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| 9. |
- Hörnblad, Emma
(author)
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Synthesis of glucuronoxylan in higher and lower plants : is there conservation of the enzymatic machinery?
- 2012
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Doctoral thesis (other academic/artistic)abstract
- The hemicellulose glucuronoxylan (GX) is the second most abundant polysaccharide after cellulose in the secondary cell walls of angiosperms and contributes significantly to the properties of wood as raw materials. Despite this, very little is known about the biosynthesis of hemicellulose. The thesis is based on studies performed in Physcomitrella patens, Arabidopsis thaliana, and Populus plants with the aim to increase the understanding of glucuronoxylan synthesis, and with main focus on the role of the IRX10 gene family. A number of genes have proven to be involved in GX biosynthesis in Arabidopsis, namely IRREGULAR XYLEM (IRX) 9, IRX14, IRX8, FRAGILE FIBER (FRA) 8 and PARVUS. This thesis presents two new genes, IRX10 and its close homolog IRX10- LIKE (L), which can now be added to the group of presumed GX biosynthesis genes. In addition, identification and characterisation of three homologs (IRX9-L, IRX14-L and F8H) of previously identified GX synthesis genes is described. Complementation experiments and morphological studies confirmed redundancy between the IRX9 and IRX9-L, IRX14 and IRX14-L, and the FRA8 and F8H pairs of genes in Arabidopsis. A bioinformatics based approach has led to the identification of four putative homologs in Populus trichocarpa (PtGT47A-1, PtGT47A-2, PtGT47D-1, and PtGT47D-4) of AtIRX10, and one putative homolog from Physcomitrella (PpGT47D). Experiments further confirmed functional conservation between the Arabidopsis (IRX10) and Populus GT47A proteins, and partial functional conservation between the Populus GT47D, the Physcomitrella GT47D and Arabidopsis IRX10 proteins. The work supports the existence of an Arabidopsis GX backbone biosynthesis complex in which AtIRX10 and AtIRX10-L form an essential component together with AtIRX9 and AtIRX14. It also suggests that parts of the GX biosynthesis machinery are conserved across embryophytes. Finally, work presented in this thesis indicates that the IRX10 gene family has gone through a subfunctionalisation event during the evolution.
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| 10. |
- Lehrman, Anna, et al.
(author)
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Framtidens mat - om husdjursavel och växtförädling
- 2014
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Book (other academic/artistic)abstract
- Du har kanske inte funderat över varför tomater ser ut som de gör, varför våra husdjur är så lugna och vänliga, eller hur det är möjligt att köpa en vattenmelon utan kärnor. Trots att växtförädling och djuravel har format det mesta vi äter, är det få människor som är medvetna om vilka vetenskapliga upptäckter och vilket omfattande arbete som ligger bakom maten vi lägger på våra tallrikar. Med den här boken vill vi ge en översikt över domesticeringens och förädlingens bakgrund, från jordbrukets början för mer än 10 000 år sedan till dagens molekylära arbete. Vi beskriver grunderna för genernas strukturer och funktioner, varför och hur olika avels- och förädlingsmetoder används och ger en inblick i lagstiftningen kring användning av genteknik i Sverige och EU. Vi ger också en överblick över olika produkter som tagits fram genom genetisk modifiering (GM) och en sammanfattning av de ekonomiska konsekvenserna av GM-grödor. Vidare diskuterar vi etiska frågor som rör avel och förädling i allmänhet och genetisk modifiering i synnerhet.
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