| 1. |
- Munthe, Christian, 1962
(author)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Book (other academic/artistic)abstract
- This volume outlines and analyses ethical issues actualized by applying a precautionary approach to the regulation of new biotechnologies. It presents a novel way of categorizing and comparing biotechnologies from a precautionary standpoint. Based on this, it addresses underlying philosophical problems regarding the ethical assessment of decision-making under uncertainty and ignorance, and discusses how risks and possible benefits of such technologies should be balanced from an ethical standpoint. It argues on conceptual and ethical grounds for a technology neutral regulation as well as for a regulation that not only checks new technologies but also requires old, inferior ones to be phased out. It demonstrates how difficult ethical issues regarding the extent and ambition of precautionary policies need to be handled by such a regulation, and presents an overarching framework for doing so.
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| 2. |
- Sweetlove, Lee J., et al.
(author)
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Engineering central metabolism – a grand challenge for plant biologists
- 2017
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In: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 90:4, s. 749-763
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Journal article (peer-reviewed)abstract
- The goal of increasing crop productivity and nutrient-use efficiency is being addressed by a number of ambitious research projects seeking to re-engineer photosynthetic biochemistry. Many of these projects will require the engineering of substantial changes in fluxes of central metabolism. However, as has been amply demonstrated in simpler systems such as microbes, central metabolism is extremely difficult to rationally engineer. This is because of multiple layers of regulation that operate to maintain metabolic steady state and because of the highly connected nature of central metabolism. In this review we discuss new approaches for metabolic engineering that have the potential to address these problems and dramatically improve the success with which we can rationally engineer central metabolism in plants. In particular, we advocate the adoption of an iterative ‘design-build-test-learn’ cycle using fast-to-transform model plants as test beds. This approach can be realised by coupling new molecular tools to incorporate multiple transgenes in nuclear and plastid genomes with computational modelling to design the engineering strategy and to understand the metabolic phenotype of the engineered organism. We also envisage that mutagenesis could be used to fine-tune the balance between the endogenous metabolic network and the introduced enzymes. Finally, we emphasise the importance of considering the plant as a whole system and not isolated organs: the greatest increase in crop productivity will be achieved if both source and sink metabolism are engineered.
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| 3. |
- Ahmadi Afzadi, Masoud
(author)
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Genetic variation in resistance to fungal storage diseases in apple : inoculation-based screening, transcriptomics and biochemistry
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Apple is one of the economically and culturally most important fruit crops and has many health-related benefits. Apple production is, however, sensitive to several fungal diseases including blue mold, caused by Penicillium expansum. Problems are more pronounced in organic production or in countries where postharvest application of fungicides is prohibited. To limit or overcome this problem, many studies have been focused on investigations of the mechanism of resistance/tolerance. No major gene(s) have as yet been identified, but quantitatively inherited traits, some of which are related to fruit texture and content of chemical compounds, have been shown to affect the ability of cultivars to withstand storage diseases. In the present thesis, inter-cultivar variation in terms of resistance to fungal storage diseases was investigated at two locations, i.e. Balsgård in Sweden and Njøs in Norway. The association of harvest date, fruit firmness and softening with lesion decay was investigated on large sets of cultivars. The contribution of four fruit texture-related genes (Md-ACO1, Md-ACS1, Md-Exp7 and Md-PG1) in explaining the fruit texture characteristics was examined. Fruit content of chemical compounds with a potential impact on disease resistance was also investigated, and finally the regulation of apple genes upon fungal infection was studied in order to identify candidate genes responsible for disease resistance. Inoculation-based screening indicated large variation across the investigated cultivars in terms of blue mold and bitter rot susceptibility. Harvest date and softening rate of fruits during storage had a large impact on resistance to fungal diseases, thus cultivars with moderate to firm fruits that soften comparatively little during storage could withstand the fungal infection comparatively well. Softening rate is, in its turn, closely associated with harvest date whereas four fruit texture-related genes had lower predictive power than expected. Quantifying the chemical compounds in the fruit samples revealed that some of these compounds, especially flavonols and procyanidin B2, could contribute to resistance against blue mold, whereas contents of malic acids or total titratable acidity had considerably less impact. Differential expression of FLS, LDOX, and CHS genes involved in biosynthesis of flavonoids and PGIP, TT10, WAK1 and CTL1 genes related to cell wall structure indicate the importance of fruit characteristics and biochemical compounds in the resistance mechanism.
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| 4. |
- Andersson, Mariette, et al.
(author)
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Genome editing in potato via CRISPR-Cas9 ribonucleoprotein delivery
- 2018
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In: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 164, s. 378-384
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Journal article (peer-reviewed)abstract
- Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein-9 (CRISPR-Cas9) can be used as an efficient tool for genome editing in potato (Solanum tuberosum). From both a scientific and a regulatory perspective, it is beneficial if integration of DNA in the potato genome is avoided. We have implemented a DNA-free genome editing method, using delivery of CRISPR-Cas9 ribonucleoproteins (RNPs) to potato protoplasts, by targeting the gene encoding a granule bound starch synthase (GBSS, EC 2.4.1.242). The RNP method was directly implemented using previously developed protoplast isolation, transfection and regeneration protocols without further adjustments. Cas9 protein was preassembled with RNA produced either synthetically or by in vitro transcription. RNP with synthetically produced RNA (cr-RNP) induced mutations, i.e. indels, at a frequency of up to 9%, with all mutated lines being transgene-free. A mutagenesis frequency of 25% of all regenerated shoots was found when using RNP with in vitro transcriptionally produced RNA (IVT-RNP). However, more than 80% of the shoots with confirmed mutations had unintended inserts in the cut site, which was in the same range as when using DNA delivery. The inserts originated both from DNA template remnants from the in vitro transcription, and from chromosomal potato DNA. In 2-3% of the regenerated shoots from the RNP-experiments, mutations were induced in all four alleles resulting in a complete knockout of the GBSS enzyme function.
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| 5. |
- Burra, Dharani
(author)
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Defence related molecular signalling in Potato : new perspectives from “- Omics”
- 2016
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Doctoral thesis (other academic/artistic)abstract
- Potato production is hampered by several pathogens and is subjected to intense chemical based disease control, use of which also has undesirable consequences. Resistance breeding programs have also shown limited success. Hence, there is a need to develop durable disease resistance. Omics-techniques enable new layers of knowledge regarding molecules and their interactions mediating defence, which can contribute to identification of durable resistance sources. A novel network-based approach was used to improve the existing annotation of gene probes on the genome based microarray. Approximately 8000 unannotated probes received a new annotation. This improved annotation was used to assess genome wide changes in transcripts and proteins in response to treatments with resistance inducers, β- amino butyric acid (BABA) and Phosphite based salt (Phi). Five thousand transcripts were significantly regulated 48 hours after 10mM BABA treatment while one was regulated with 1mM BABA. In coherence, 10 mM BABA but not 1 mM induced protection to the hemibiotroph Phytophthora infestans. No transcript was significantly regulated 48 hours after Phi treatment. Time course analysis revealed that Phi exerts a transient effect, as significant transcriptomic changes were observed only 3, 6 and 11 hours after treatment. In contrast, plants showed resistance to P. infestans even at 120 hours after Phi treatment. Phi and BABA dependent “Induced state” is not restricted to transcripts related to plant defence, as transcripts related to abiotic stress and primary metabolism were altered, while biotic stress and cell wall related proteins also increased in abundance. Furthermore, an in vitro based blackleg disease screening assay was developed to investigate Potato – Dickeya solani interactions. We show that salicylic (SA) and COI1 are necessary for defence in shoots and tubers to this necrotroph. We also screened a crossing population and identified “potential” D. solani susceptibility genes related to transcriptional regulation. We also show that while SA is necessary to restrict lesion development and pathogen growth in response to the necrotroph Alternaria solani, COI1 affects pathogen growth only. Transcriptomic analysis indicated that rapid defence response to A. solani involves biotic, abiotic and oxidative stress related transcripts regulated by SA and COI1. We identified a citrate binding protein, which is also induced by resistance inducers, as an SA-repressed susceptibility factor to A. solani. Finally, proteomics of PAMP triggered immunity revealed upregulation of oxidative stress proteins while proteins related to oxidative stress tolerance, GTP binding activity were specifically upregulated in effector triggered immunity interactions.
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| 6. |
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| 7. |
- Calleja-Rodriguez, Ainhoa
(author)
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Quantitative Genetics and Genomic Selection of Scots pine
- 2019
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Doctoral thesis (other academic/artistic)abstract
- The final objective of tree improvement programs is to increase the frequency of favourable alleles in a population, for the traits of interest within the breeding programs. To achieve this, it is crucial to decompose the phenotypic variance accurately into its genetic and environmental components in order to obtain a precise estimation of genetic parameters and to increase genetic gains. The overall aim of this thesis was to increase the accuracy of genetic parameter estimation by incorporating new quantitative genetics models to the analysis of multiple traits in multiple trials of Scots pine, and to develop a genomic selection protocol to accelerate genetic gain. Factor analysis was incorporated to multivariate multi-environment analyses and it allowed to evaluate up to 19 traits simultaneously. As a result, precise patterns of genotype-by-environment interactions (G E) were observed for tree vitality and height; moreover, it was possible to detect the main driver of the G E: differences in temperature sum among sites. Traditional quantitative trait loci (QTL) analysis of phenotypic data was compared with the detection of QTL with estimated breeding values (EBV) for the first time in a three generation pedigree and, as outcome, it was noticed that if a QTL was associated to a EBV and to a phenotypic trait, the proportion of variance explained by the QTLEBV was higher than the QTL-phenotype. Additionally, several QTL were detected across several ages, which may make them suitable as candidates for early selection. Genomic selection (GS) could aid to reduce the breeding cycle by shortening the periods of progeny field testing, and consequently increasing genetic gains per year. Genomic predictions, including additive and non-additive effects through different prediction models were compared with traditional pedigree-based models; it was seen an overestimation of genetic parameters for pedigree-based models, even larger when nonadditive effects could not be discerned from additive and residual effects. Prediction accuracies and abilities of the genomic models were sufficient to achieve higher selection efficiencies and responses per year varying between 50-90% by shortening 50% the breeding cycle. For the selection of the top 50 individuals, higher gains were estimated if non-additive effects are incorporated to the models (7 – 117%).
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| 8. |
- Dida, Mulatu Geleta, et al.
(author)
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Genetic Diversity within a Global Panel of Durum Wheat (Triticum durum) Landraces and Modern Germplasm Reveals the History of Alleles Exchange
- 2017
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In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 8
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Journal article (peer-reviewed)abstract
- Durum wheat is the 10th most important crop in the world, and its use traces back to the origin of agriculture. Unfortunately, in the last century only part of the genetic diversity available for this species has been captured in modern varieties through breeding. Here, the population structure and genetic diversity shared among elites and landraces collected from 32 countries was investigated. A total of 370 entries were genotyped with Axiom 35K array to identify 8,173 segregating single nucleotide polymorphisms (SNPs). Of these, 500 were selected as highly informative with a PIC value above 0.32 and used to test population structure via DAPC, STRUCTURE, and neighbor joining tree. A total of 10 sub-populations could be identified, six constituted by modern germplasm and four by landraces of different geographical origin. Interestingly, genomic comparison among groups indicated that Middle East and Ethiopia had the lowest level of allelic diversity, while breeding programs and landraces collected outside these regions were the richest in rare alleles. Further, phylogenetic analysis among landraces indicated that Ethiopia might represent a second center of origin of durum wheat, rather than a second domestication site as previously believed. Together, the analyses carried here provide a global picture of the available genetic diversity for this crop and shall guide its targeted use by breeders.
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| 9. |
- Dida, Mulatu Geleta, et al.
(author)
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Molecular and Genomic Tools Provide Insights on Crop Domestication and Evolution
- 2016
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In: Advances in Agronomy. - : Elsevier. - 0065-2113 .- 2213-6789. ; 135, s. 181-223
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Research review (peer-reviewed)abstract
- Rapid progress in genomic research and the development of genome-wide molecular markers for various crops significantly improved our knowledge on plant domestication and evolution. Molecular markers and other genomic tools have been used to understand the evolutionary changes that converted wild plants into domesticated crops, and the identification of loci behind domestication syndrome traits will have significant importance in the fast-track domestication of new plants. The application of genomics- assisted selection in plant breeding programs has significantly contributed to efficient plant breeding for desirable traits. Genomic tools also facilitated the efficient identification of progenitors of crops as well as centers of domestication. Multiple genomic regions with signature of selection during plant domestication have been found in various crops. Extensive analyses of plant genomes revealed that genes underlying domestication syndrome traits show a significant loss of diversity, for example, up to 95% of genetic diversity in wild relatives has been lost during domestication process in extreme cases. Genomic research revealed repeated occurrence of polyploidization during plant evolution and various interesting events that occurred following polyploidization such as gene loss and silencing. The loss of most replicated genes through time and nonrandom retention of some duplicated genes that serve as signatures of polyploidy are among interesting changes in polyploid plant genomes. Further insights into the advances in our knowledge on plant domestication and evolution made through the use of DNA markers and genomic tools is provided in this paper.
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| 10. |
- Dubey, Mukesh
(author)
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Relationship of downy mildew resistance with yield related traits helpful for achieving reliable selection criteria in opium poppy (Papaver somniferum L.)
- 2015
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In: Indian Journal Of Genetics And Plant Breeding. - : The Indian Society of Genetics and Plant Breeding. - 0019-5200 .- 0975-6906. ; 75, s. 396-399
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Journal article (peer-reviewed)abstract
- Present study aims to understand the nature and degree of relationships between different morphometric and yield influencing traits using correlation and path coefficient analysis in medicinally important plant opium poppy. Genotypic and phenotypic correlation coefficients analysis showed significant negative correlation between downy mildew disease severity Index (DSI) and seed and straw yield. Furthermore, path analysis showed direct and positive effect of capsule diameter and number of capsule/plant to straw yield. In contrast, DSI had highest direct and negative contribution to straw yield. These results support effectiveness of selections for high seed and straw yield together with downey mildew-resistance in development of effective selection criteria for crop improvement.
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