| 1. |
- Munthe, Christian, 1962
(författare)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Bok (övrigt vetenskapligt/konstnärligt)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. |
- Sandin, Per, et al.
(författare)
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Technology neutrality and regulation of agricultural biotechnology
- 2018
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Ingår i: Professionals in food chains: ethics, rules and responsibility. EurSafe 2018, Vienna, Austria 13 – 16 June 2018 / edited by: Svenja Springer, Herwig Grimm. - Wageningen, Netherlands : Wageningen Academic Publishers. - 9789086863211
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Konferensbidrag (refereegranskat)abstract
- Agricultural biotechnology, in particular genetically modified organisms (GMOs), is subject to regulation in many areas of the world, not least in the European Union (EU). A number of authors have argued that those regulatory processes are unfair, costly, and slow and that regulation therefore should move in the direction of increased ‘technology neutrality’. The issue is becoming more pressing, especially since new biotechnologies such as CRISPR increasingly blur the regulatory distinction between GMOs and non-GMOs. This paper offers a definition of technology neutrality, uses the EU GMO regulation as a starting point for exploring technology neutrality, and presents distinctions between variants of the call for technology neutral GMO regulation in the EU.
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| 3. |
- Sweetlove, Lee J., et al.
(författare)
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Engineering central metabolism – a grand challenge for plant biologists
- 2017
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Ingår i: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 90:4, s. 749-763
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Ahmadi Afzadi, Masoud
(författare)
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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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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)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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| 5. |
- Andersson, Mariette, et al.
(författare)
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Genome editing in potato via CRISPR-Cas9 ribonucleoprotein delivery
- 2018
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 164, s. 378-384
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Burra, Dharani
(författare)
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Defence related molecular signalling in Potato : new perspectives from “- Omics”
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)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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| 7. |
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| 8. |
- Calleja-Rodriguez, Ainhoa
(författare)
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Quantitative Genetics and Genomic Selection of Scots pine
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)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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| 9. |
- Dida, Mulatu Geleta, et al.
(författare)
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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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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 8
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Dida, Mulatu Geleta, et al.
(författare)
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Molecular and Genomic Tools Provide Insights on Crop Domestication and Evolution
- 2016
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Ingår i: Advances in Agronomy. - : Elsevier. - 0065-2113 .- 2213-6789. ; 135, s. 181-223
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Forskningsöversikt (refereegranskat)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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| 11. |
- Dubey, Mukesh
(författare)
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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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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Eriksson, Dennis, et al.
(författare)
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Measuring the impact of plant breeding on sub-Saharan African staple crops
- 2018
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Ingår i: Outlook On Agriculture. - : SAGE Publications. - 0030-7270 .- 2043-6866. ; 47, s. 163-180
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Forskningsöversikt (refereegranskat)abstract
- Many countries in sub-Saharan Africa (SSA) are facing huge challenges regarding food insecurity, low agricultural output, and agriculturally incurred environmental degradation. A sustainable and increased crop productivity and diversity is essential to achieve food security in a socially, economically, and environmentally sustainable way. Plant breeding is an important factor contributing to the increased crop productivity and diversity, giving farmers access to genetically improved cultivars that yield more, have better resistance to biotic and abiotic stresses, and meet consumer expectations. To motivate and encourage further investments, it is important to measure the actual impact of breeding. This review considers available research on the impact of breeding through yield gain and of food security, focusing on 10 important staple crops in SSA. The overall impression is that breeding produces a very high return on investment. Such investments remain centerpieces for meeting the challenges in this region. The discussion focuses on the most important future breeding priorities for each crop, the actors involved, and the importance of mechanisms for dissemination and farmer adoption, and concludes with some policy recommendations.
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| 16. |
- Eriksson, Dennis, et al.
(författare)
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Overview and Breeding Strategies of Table Potato Production in Sweden and the Fennoscandian Region
- 2016
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Ingår i: Potato Research. - : Springer Science and Business Media LLC. - 0014-3065 .- 1871-4528. ; 59, s. 279-294
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Tidskriftsartikel (refereegranskat)abstract
- Recent reductions in the public commitment to potato breeding in Sweden, Norway and Finland call for an evaluation of the current situation regarding the commercial basis for, and structure of, potato breeding in these countries. We here review the extent of cultivation, processing and consumption of table potato in Sweden, as well as provide an overview of the potato breeding tools and programmes in the three countries. We then discuss various strategies to provide long-term stability and increase the impact of public potato breeding, based on the similar overall conditions for potato cultivation across the Fennoscandian region. The conclusions are twofold; first, an increased long-term funding of the public potato breeding programmes is necessary to maintain a minimum level of material, and second, a coordination of the breeding activities in the Fennoscandian region would be of great benefit to all involved stakeholders and allow an enhancement of the current national breeding programmes. In addition, we propose a minimum first field year population size for potato breeding.
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| 17. |
- Eriksson, Dennis
(författare)
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Regulatory hurdles for genome editing: process- vs. product-based approaches in different regulatory contexts
- 2016
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 0721-7714 .- 1432-203X. ; 35, s. 1493-1506
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Tidskriftsartikel (refereegranskat)abstract
- Novel plant genome editing techniques call for an updated legislation regulating the use of plants produced by genetic engineering or genome editing, especially in the European Union. Established more than 25 years ago and based on a clear distinction between transgenic and conventionally bred plants, the current EU Directives fail to accommodate the new continuum between genetic engineering and conventional breeding. Despite the fact that the Directive 2001/18/EC contains both process- and product-related terms, it is commonly interpreted as a strictly process-based legislation. In view of several new emerging techniques which are closer to the conventional breeding than common genetic engineering, we argue that it should be actually interpreted more in relation to the resulting product. A legal guidance on how to define plants produced by exploring novel genome editing techniques in relation to the decade-old legislation is urgently needed, as private companies and public researchers are waiting impatiently with products and projects in the pipeline. We here outline the process in the EU to develop a legislation that properly matches the scientific progress. As the process is facing several hurdles, we also compare with existing frameworks in other countries and discuss ideas for an alternative regulatory system.
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| 18. |
- Hennigs, Lars
(författare)
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FLOWERING LOCUS T Triggers Early and Fertile Flowering in Glasshouse Cassava (Manihot esculenta Crantz)
- 2017
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Ingår i: Plants. - : MDPI AG. - 2223-7747. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Accelerated breeding of plant species has the potential to help challenge environmental and biochemical cues to support global crop security. We demonstrate the over-expression of Arabidopsis FLOWERING LOCUS T in Agrobacterium-mediated transformed cassava (Manihot esculenta Crantz; cultivar 60444) to trigger early flowering in glasshouse-grown plants. An event seldom seen in a glasshouse environment, precocious flowering and mature inflorescence were obtained within 4–5 months from planting of stem cuttings. Manual pollination using pistillate and staminate flowers from clonal propagants gave rise to viable seeds that germinated into morphologically typical progeny. This strategy comes at a time when accelerated crop breeding is of increasing importance to complement progressive genome editing techniques.
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| 19. |
- Ivarson, Emelie
(författare)
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Development of Lepidium campestre into a new oil and catch crop
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A growing world population and dwindling fossil oil reserves demand an increase in the world plant oil production. The possibility to increase the area of cultivated land is limited due to the shortage of arable land. Also, the possibility for increasing the oil content in the limited number of cultivated oil crops is restricted. New, high-yielding oil crops, which can be grown in areas where no other oil crops can grow and have less environmental impact, need to be developed. It is preferable that such new oil crops would allow us to tailor-make the oil composition in planta for food, fuel or industrial applications. In Sweden, the main oil crop cultivated is winter rapeseed, which, due to weak winter hardiness, only can be grown in southern Sweden. Developing a new winter-hardy oilseed crop would extend the plant oil production in Sweden and other cold climate regions. Lepidium campestre is a wild Brassica species. It is very winter hardy, high-yielding, has an upright stature and synchronous flowering. Moreover, it is biennial, and thus being suitable as a catch crop. However, it needs to be domesticated first so that it possesses all important agronomic traits necessary for being a successful agricultural crop. The aim of this thesis was to improve some properties of L. campestre by genetic engineering with focus on: the seed oil content, pod shatter, seed oil composition and wax ester production in the seed oil. In order to enable genetic engineering of this wild species, a well-functioning regeneration and transformation protocol was first developed, which has greatly facilitated the subsequent genetic improvements of the target traits of the species. Through RNAi-down-regulation of the FAD2 and FAE1 genes, transgenic lines with oxidative stable oil high in oleic acid were generated, indicating the potential of the species for being used for food oil purposes. Moreover, transgenic lines with increased seed oil content were developed by expressing either the AtWRI1 or AtHb2 or BvHb2 gene. Transgenic lines with pod shatter resistance were produced by RNAi down-regulation of the IND gene. Wax esters were produced in this species by expression of the jojoba wax synthesis genes, showing the potential of the species as a new platform for industrial oil production. These transgenic lines are valuable materials for further breeding of this species.
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| 20. |
- Ivarson, Emelie, et al.
(författare)
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Effects of overexpression of WRI1 and hemoglobin genes on the seed oil content of Lepidium campestre
- 2017
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The wild species field cress (Lepidium campestre), belonging to the Brassicaceae family, has potential to be developed into a novel oilseed- and catch crop, however, the species needs to be further improved regarding some important agronomic traits. One of them is its low oil content which needs to be increased. As far as we know there is no study aiming at increasing the oil content that has been reported in this species. In order to investigate the possibility to increase the seed oil content in field cress, we have tried to introduce the Arabidopsis WRINKLED1 (AtWRI1) or hemoglobin (Hb) genes from either Arabidopsis thaliana (AtHb2) or Beta vulgaris (BvHb2) into field cress with the seed specific expression. The hypothesis was that the oil content would be increased by overexpressing these target genes. The results showed that the oil content was indeed increased by up to 29.9, 20.2, and 25.9% in the transgenic lines expressing AtWRI1, AtHb2, and BvHb2, respectively. The seed oil composition of the transgenic lines did not significantly deviate from the seed oil composition of the wild type plants. Our results indicate that genetic modification can be used in this wild species for its fast domestication into a future economically viable oilseed and catch crop.
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| 21. |
- Jin, Yunkai, et al.
(författare)
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New Energy Crops for Biofuel Production
- 2015
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Ingår i: Handbook of clean energy systems. - Chichester, UK : John Wiley & Sons, Ltd. - 9781118388587 ; , s. 49-62
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Bokkapitel (refereegranskat)
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| 22. |
- Mehrabi, Sara, 1982-, et al.
(författare)
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The constitutive expression and induction of three β-1,3-glucanases by bird cherry-oat aphid in relation to aphid resistance in 15 barley breeding lines
- 2016
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Ingår i: Arthropod-Plant Interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 10:2, s. 101-111
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Tidskriftsartikel (refereegranskat)abstract
- In this study, 15 closely related barley genotypes were analyzed for the abundance of three β-1,3-glucanase transcripts immediately before and during infestation by the bird cherry-oat aphid (Rhopalosiphum padi L.). The barley lines are doubled haploid lines in backcross (BC) generations BC1 and BC2 from a cross between cultivar Lina and a wild barley accession. Previously, they have been characterized as susceptible (S) or resistant (R) to R. padi based on their ability to support nymphal growth. Here we also tested whether resistance was manifested as reduced aphid settling on the plants. Indeed, aphid numbers were lower on R than on S lines in all cases where there were significant differences between R and S lines. The choice of β-1,3-glucanase sequences is based on earlier results comparing two S and two R genotypes, suggesting that at least two of the three studied sequences are susceptibility factors. The comparisons of transcript abundance in plants with aphids showed for two of the β-1,3-glucanase sequences that there were several cases where an S genotype had significantly higher abundance than an R genotype, and in no case did an R line have significantly higher abundance than an S line. Thus, there was some support for the idea that β-1,3-glucanase sequences are susceptibility factors in the interaction between barley and R. padi.
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| 23. |
- Nemesio Gorriz, Miguel
(författare)
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Molecular responses against Heterobasidion annosum s.l. in Picea abies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Norway spruce [Picea abies (L.) Karst.] is a main tree species in European forests and is important both ecologically and economically. The root rot fungus Heterobasidion annosum sensu lato (s.l.) is the main P. abies pathogen. Including resistance in breeding programs would help mitigating the impact of the pathogen but knowledge regarding defense mechanisms in P. abies needs a better understanding. The work within this thesis intended to expand the existing knowledge on P. abies resistance mechanisms focusing on hormone signaling, flavonoid biosynthesis and its transcriptional regulation. I found that jasmonic acid is the major hormone controlling defense signaling pathways in P. abies. Furthermore, we validated a candidate gene, PaLAR3, as a resistance marker for H. annosum s.l. in P. abies. PaLAR3 encodes an enzyme responsible for the synthesis of (+) catechin, which showed a fungistatic effect on H. parviporum. Analysis of genetic diversity revealed two allelic lineages of PaLAR3 that showed significant differences in fungal resistance and (+) catechin content that were explained by dissimilarities in inducibility. We studied the role of PaNAC03, a transcription factor that is associated with H. annosum s.l. infection. PaNAC03 not only showed repression of multiple genes including PaLAR3, but bound only to the promoter of one of the PaLAR3 allelic lineages explaining at least partly the differences in allelic expression that were observed. Finally, we identified a full repertoire of members of a MYB/bHLH/WDR transcription factor complex in Norway spruce, which showed differences in protein interactions and expression patterns, and also in ability to control the expression of genes in the flavonoid biosynthetic pathway including PaLAR3.
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| 24. |
- Nybom, Hilde, et al.
(författare)
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Analysis of the genetic diversity and structure across a wide range of germplasm reveals prominent gene flow in apple at the European level
- 2016
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Background: The amount and structure of genetic diversity in dessert apple germplasm conserved at a European level is mostly unknown, since all diversity studies conducted in Europe until now have been performed on regional or national collections. Here, we applied a common set of 16 SSR markers to genotype more than 2,400 accessions across 14 collections representing three broad European geographic regions (North + East, West and South) with the aim to analyze the extent, distribution and structure of variation in the apple genetic resources in Europe.Results: A Bayesian model-based clustering approach showed that diversity was organized in three groups, although these were only moderately differentiated (F-ST = 0.031). A nested Bayesian clustering approach allowed identification of subgroups which revealed internal patterns of substructure within the groups, allowing a finer delineation of the variation into eight subgroups (F-ST = 0.044). The first level of stratification revealed an asymmetric division of the germplasm among the three groups, and a clear association was found with the geographical regions of origin of the cultivars. The substructure revealed clear partitioning of genetic groups among countries, but also interesting associations between subgroups and breeding purposes of recent cultivars or particular usage such as cider production. Additional parentage analyses allowed us to identify both putative parents of more than 40 old and/or local cultivars giving interesting insights in the pedigree of some emblematic cultivars.Conclusions: The variation found at group and subgroup levels may reflect a combination of historical processes of migration/selection and adaptive factors to diverse agricultural environments that, together with genetic drift, have resulted in extensive genetic variation but limited population structure. The European dessert apple germplasm represents an important source of genetic diversity with a strong historical and patrimonial value. The present work thus constitutes a decisive step in the field of conservation genetics. Moreover, the obtained data can be used for defining a European apple core collection useful for further identification of genomic regions associated with commercially important horticultural traits in apple through genome-wide association studies.
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| 25. |
- Nybom, Hilde, et al.
(författare)
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Nordiska äpplen – projekt NordApp
- 2015
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- Frukt av många olika slag odlas över hela världen, och utgör en viktig del av den totala livsmedelsförsörjningen. I varmare länder är mångfalden stor – former och färger bildar en förförande palett om man besöker en fruktmarknad, liksom doft och smak hos de frukter man väljer att bekanta sig närmare med. I de nordiska länderna sätter klimatet dessvärre stopp för merparten av dessa frukter – men vi har lyckligtvis några, främst kärn- och stenfrukter inom familjen Rosaceae. Äpple har sålunda odlats i de nordiska länderna sedan början av medeltiden, och detta är numera vår i särklass viktigaste frukt, såväl kulturellt som ekonomiskt. Vissa utländska äpplesorter fungerar ganska bra i odling även på våra breddgrader men för merparten blir den korta vegetationsperioden och de stränga vintrarna övermäktiga hinder. Offentligt finansierade växtförädlingsprogram har därför bedrivits i Finland, Norge och Sverige för att ta fram klimatanpassade sorter. På senare tid har ökad omsorg om miljö och hälsa aktualiserat ytterligare ett förädlingsmål: resistens mot olika skadegörare.
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