| 1. |
- Bannak Gedara, Shishanthi Jayarathna, et al.
(författare)
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High fructan barley lines produced by selective breeding may alter beta-glucan and amylopectin molecular structure
- 2023
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Ingår i: Carbohydrate Polymers. - 0144-8617. ; 316
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Tidskriftsartikel (refereegranskat)abstract
- Six cross-bred barley lines developed by a breeding strategy with the target to enhance the fructan synthesis activity and reduce the fructan hydrolysis activity were analyzed together with their parental lines, and a reference line (Gustav) to determine whether the breeding strategy also affected the content and molecular structure of amylopectin and beta-glucan. The highest fructan and beta-glucan content achieved in the novel barley lines was 8.6 % and 12 %, respectively (12.3-fold and 3.2-fold higher than in Gustav). The lines with low fructan synthesis activity had higher starch content, smaller building blocks in amylopectin, and smaller structural units of beta-glucans than the lines with high-fructan synthesis activity. Correlation analysis confirmed that low starch content was associated with high amylose, fructan, and beta-glucan content, and larger building blocks in amylopectin.
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| 2. |
- Andersson, Mariette, et al.
(författare)
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A simplified method of determining the internal structure of amylopectin from barley starch without amylopectin isolation
- 2021
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 255
-
Tidskriftsartikel (refereegranskat)abstract
- To determine the internal structure of barley starch without amylopectin isolation, whole starch was hydrolyzed using beta-amylase to remove the linear amylose and obtain beta-limit dextrins (beta-LDs). The beta-LDs were treated with extensive a-amylase to prepare alpha-limit dextrins (alpha-LDs), and the alpha-LDs were further hydrolyzed with beta-amylase into building blocks. The chain-length distribution of beta-LD and building block composition were analyzed by sizeexclusion chromatography and anion-exchange chromatography. The internal structure of the barley whole starches had similar pattern to barley amylopectins analyzed by conventional methods. The starch of barley amol-mutated varieties contained more short internal B-chains and less long internal B-chains than that of other varieties. The starch from amol-mutated varieties had more large building blocks than that from waxy varieties. The simplified method presented in this study can effectively characterize starch internal structure that relates to physicochemical properties of starch, although some details of amylopectin structure are not assessable.
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| 3. |
- Andersson, Mariette, et al.
(författare)
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Resistant starch and other dietary fiber components in tubers from a high-amylose potato
- 2018
-
Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 251, s. 58-63
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Tidskriftsartikel (refereegranskat)abstract
- Tubers from a genetically modified high-amylose line T-2012 and its parental potato cultivar Dinamo were analyzed for resistant starch (RS) and dietary fiber (DF) after cooking and cold storage. For uncooked potatoes, the high-amylose tubers (30% of dry matter, DM) had much lower RS than the parent tubers (56% of DM). However, after cooking, the high-amylose tubers gave more RS (13% of DM) than the parent (4% of DM), and the RS level increased further to about 20% of DM after 1 day of cold storage. The altered RS content was attributable to changes in amylose content, starch granule structure, and amylopectin structure induced by the genetic modification. The high-amylose tubers also contained more DF (10-14% of DM) than the parent (5-7% of DM). Furthermore, cell wall composition was indirectly affected by the genetic modification, giving more cellulose and less pectin in the high-amylose tubers than the parent.
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| 4. |
- Bannak Gedara, Shishanthi Jayarathna, et al.
(författare)
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Recent Advances in Starch-Based Blends and Composites for Bioplastics Applications
- 2022
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 14
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Forskningsöversikt (refereegranskat)abstract
- Environmental pollution by synthetic polymers is a global problem and investigating substitutes for synthetic polymers is a major research area. Starch can be used in formulating bioplastic materials, mainly as blends or composites with other polymers. The major drawbacks of using starch in such applications are water sensitivity and poor mechanical properties. Attempts have been made to improve the mechanical properties of starch-based blends and composites, by e.g., starch modification or plasticization, matrix reinforcement, and polymer blending. Polymer blending can bring synergetic benefits to blends and composites, but necessary precautions must be taken to ensure the compatibility of hydrophobic polymers and hydrophilic starch. Genetic engineering offers new possibilities to modify starch inplanta in a manner favorable for bioplastics applications, while the incorporation of antibacterial and/or antioxidant agents into starch-based food packaging materials brings additional advantages. In conclusion, starch is a promising material for bioplastic production, with great potential for further improvements. This review summarizes the recent advances in starch-based blends and composites and highlights the potential strategies for overcoming the major drawbacks of using starch in bioplastics applications.
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| 5. |
- Jayarathna, Shishanthi, et al.
(författare)
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GBSS mutations in an SBE mutated background restore the potato starch granule morphology and produce ordered granules despite differences to native molecular structure
- 2024
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Potato starch with mutations in starch branching enzyme genes (SBEI, SBEII) and granule-bound starch synthase gene (GBSS) was characterized for molecular and thermal properties. Mutations in GBSS were here stacked to a previously developed SBEI and SBEII mutation line. Additionally, mutations in the GBSS gene alone were induced in the wild-type variety for comparison. The parental line with mutations in the SBE genes showed a ∼ 40 % increase in amylose content compared with the wild-type. Mutations in GBSS-SBEI-SBEII produced non-waxy, low-amylose lines compared with the wild-type. An exception was a line with one remaining GBSS wild-type allele, which displayed ∼80 % higher amylose content than wild-type. Stacked mutations in GBSS in the SBEI-SBEII parental line caused alterations in amylopectin chain length distribution and building block size categories of whole starch. Correlations between size categories of building blocks and unit chains of amylopectin were observed. Starch in GBSS-SBEI-SBEII mutational lines had elevated peak temperature of gelatinization, which was positively correlated with large building blocks.
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| 6. |
- Menzel, Carolin, et al.
(författare)
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Improved material properties of solution-cast starch films : Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes
- 2015
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 130, s. 388-397
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Tidskriftsartikel (refereegranskat)abstract
- High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural changes in amylopectin enhanced film-forming behavior and improved barrier and tensile properties in starch films. The molecular structure in these starches was related to film-forming properties. Solution-cast films of high-amylose starch revealed a homogeneous structure with increasing surface roughness at higher amylose content, possibly due to amylose aggregation. Films exhibited significantly higher stress and strain at break compared with films of wild-type starch, which could be attributable to the longer chains of amylopectin being involved in the interconnected network and more interaction between chains, as shown using transmission electron microscopy. The oxygen permeability of high-amylose starch films was significantly decreased compared with wild-type starch. The nature of the modified starches makes them an interesting candidate for replacement of non-renewable oxygen and grease barrier polymers used today.
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| 7. |
- Zhao, Xue, et al.
(författare)
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Amylose starch with no detectable branching developed through DNA-free CRISPR-Cas9 mediated mutagenesis of two starch branching enzymes in potato
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- DNA-free genome editing was used to induce mutations in one or two branching enzyme genes (Sbe) in tetraploid potato to develop starch with an increased amylose ratio and elongated amylopectin chains. By using ribonucleoprotein (RNP) transfection of potato protoplasts, a mutation frequency up to 72% was achieved. The large variation of mutations was grouped as follows: Group 1 lines with all alleles of Sbe1 mutated, Group 2 lines with all alleles of Sbe1 as well as two to three alleles of Sbe2 mutated and Group 3 lines having all alleles of both genes mutated. Starch from lines in Group 3 was found to be essentially free of amylopectin with no detectable branching and a chain length (CL) distribution where not only the major amylopectin fraction but also the shortest amylose chains were lost. Surprisingly, the starch still formed granules in a low-ordered crystalline structure. Starch from lines of Group 2 had an increased CL with a higher proportion of intermediate-sized chains, an altered granule phenotype but a crystalline structure in the granules similar to wild-type starch. Minor changes in CL could also be detected for the Group 1 starches when studied at a higher resolution.
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| 8. |
- Zhao, Xue, et al.
(författare)
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Internal structure and thermal properties of potato starches varying widely in amylose content
- 2023
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 135
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Tidskriftsartikel (refereegranskat)abstract
- The correlation between starch internal structure and thermal properties (gelatinisation and retrogradation) was studied in starches of wild-type potatoes and potatoes from the lines with altered starch synthase or branching enzyme activities (GBSS, SS, SBE), representing a range of amylose:amylopectin ratio from 2 to >99.5% amylopectin. The different potato lines were divided into Group 1-8 depending on the mutation targets. The internal chain distribution and building block composition of beta-limit dextrins (beta-LDs) in the whole starches were analysed by high-performance anion-exchange chromatography (HPAEC) and high-performance size -exclusion chromatography (HPSEC) based on a recently developed simplified method. The building blocks were categorised into five size groups (G2-G6). Thermal properties of the starches were investigated using differential scanning calorimetry (DSC). The proportion of fingerprint B-chains with the degree of polymerisation 4-7, and the composition of intermediate (G4) and large (G5 and G6) building blocks of starches generally decreased in the order of potato lines from Group 2 (full Sbe1 and partial Sbe2 mutated)>Group 1 (full Sbe1 mutated)>wild-type > Group 7 (full Gbss and Ss2, and partial Ss3 mutated)>Group 8 (full Gbss, Ss2, and Ss3 mutated). The starch of amylopectin-rich potato lines from Group 8 with multiple genes targeted and the highest degree of mutations showed the lowest enthalpy of gelatinisation (15.0 J/g of amylopectin) and retrogradation (3.1 J/g of amylo-pectin), compared to starches of potato lines from other groups. More intermediate and large building blocks led to higher gelatinisation temperatures. Retrogradation was favoured by dense structure of the amylopectins with many short internal chains.
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| 9. |
- Andersson, Mariette
(författare)
-
A Specialized Diacylglycerol Acyltransferase Contributes to the Extreme Medium-Chain Fatty Acid Content of Cuphea Seed Oil
- 2017
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 174, s. 97-109
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Tidskriftsartikel (refereegranskat)abstract
- Seed oils of many Cuphea sp. contain.90% of medium-chain fatty acids, such as decanoic acid (10: 0). These seed oils, which are among the most compositionally variant in the plant kingdom, arise from specialized fatty acid biosynthetic enzymes and specialized acyltransferases. These include lysophosphatidic acid acyltransferases (LPAT) and diacylglycerol acyltransferases (DGAT) that are required for successive acylation of medium-chain fatty acids in the sn-2 and sn-3 positions of seed triacylglycerols (TAGs). Here we report the identification of a cDNA for a DGAT1-type enzyme, designated CpuDGAT1, from the transcriptome of C. avigera var pulcherrima developing seeds. Microsomes of camelina (Camelina sativa) seeds engineered for CpuDGAT1 expression displayed DGAT activity with 10:0-CoA and the diacylglycerol didecanoyl, that was approximately 4-fold higher than that in camelina seed microsomes lacking CpuDGAT1. In addition, coexpression in camelina seeds of CpuDGAT1 with a C. viscosissima FatB thioesterase (CvFatB1) that generates 10:0 resulted in TAGs with nearly 15 mol % of 10: 0. More strikingly, expression of CpuDGAT1 and CvFatB1 with the previously described CvLPAT2, a 10:0-CoA-specific Cuphea LPAT, increased 10:0 amounts to 25 mol % in camelina seed TAG. These TAGs contained up to 40 mol % 10:0 in the sn-2 position, nearly double the amounts obtained from coexpression of CvFatB1 and CvLPAT2 alone. Although enriched in diacylglycerol, 10:0 was not detected in phosphatidylcholine in these seeds. These findings are consistent with channeling of 10:0 into TAG through the combined activities of specialized LPAT and DGAT activities and demonstrate the biotechnological use of these enzymes to generate 10:0-rich seed oils.
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| 10. |
- Andersson, Mariette, et al.
(författare)
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An alternative pathway to plant cold tolerance in the absence of vacuolar invertase activity
- 2023
-
Ingår i: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 113, s. 327-341
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Tidskriftsartikel (refereegranskat)abstract
- To cope with cold stress, plants have developed antioxidation strategies combined with osmoprotection by sugars. In potato (Solanum tuberosum) tubers, which are swollen stems, exposure to cold stress induces starch degradation and sucrose synthesis. Vacuolar acid invertase (VInv) activity is a significant part of the cold-induced sweetening (CIS) response, by rapidly cleaving sucrose into hexoses and increasing osmoprotection. To discover alternative plant tissue pathways for coping with cold stress, we produced VInv-knockout lines in two cultivars. Genome editing of VInv in 'Desiree' and 'Brooke' was done using stable and transient expression of CRISPR/Cas9 components, respectively. After storage at 4 degrees C, sugar analysis indicated that the knockout lines showed low levels of CIS and maintained low acid invertase activity in storage. Surprisingly, the tuber parenchyma of vinv lines exhibited significantly reduced lipid peroxidation and reduced H2O2 levels. Furthermore, whole plants of vinv lines exposed to cold stress without irrigation showed normal vigor, in contrast to WT plants, which wilted. Transcriptome analysis of vinv lines revealed upregulation of an osmoprotectant pathway and ethylene-related genes during cold temperature exposure. Accordingly, higher expression of antioxidant-related genes was detected after exposure to short and long cold storage. Sugar measurements showed an elevation of an alternative pathway in the absence of VInv activity, raising the raffinose pathway with increasing levels of myo-inositol content as a cold tolerance response.
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| 11. |
- Andersson, Mariette
(författare)
-
Colour change in potato (Solanum tuberosum L.) tubers by disruption of the anthocyanin pathway via ribonucleoprotein complex delivery of the CRISPR/Cas9 system
- 2024
-
Ingår i: Plant Cell, Tissue and Organ Culture. - 0167-6857 .- 1573-5044. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Potato is an important part of the traditional Norwegian diet, and the crop faces several challenges with respect to pests and diseases, as well as the increasingly challenging changes in climate. Genome editing may provide tools to improve the resilience of Norwegian potato cultivars to new climate challenges. We have altered the skin colour of two potato cultivars, 'Desiree' and 'Nansen' from red to yellow, as a proof-of-concept for the use of CRISPR/Cas9 in a Norwegian cultivar. Our method has involved the use of protoplasts and we have grown the regenerants for three successive clonal tuber generations to evaluate the stability of the edited plants over time and under varying temperature conditions in contained rooms in a greenhouse. We found that the protoplast method is well suited to achieving CRISPR/Cas9 applications. The results show that the yellow skin is consistent over the three generations of tuber propagation. We found some suspected somaclonal variation in the protoplast regenerants. Some of the variation which we observed under high temperatures (up to nearly 40oC) during the second growth cycle, disappeared when cultivated under lower temperatures in the third cultivation cycle.
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| 12. |
- Andersson, Mariette, et al.
(författare)
-
Comparative potato genome editing: Agrobacterium tumefaciens-mediated transformation and protoplasts transfection delivery of CRISPR/Cas9 components directed to StPPO2 gene
- 2021
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 145, s. 291-305
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Tidskriftsartikel (refereegranskat)abstract
- Key message We compared the StPPO2 gene editing outcomes and efficiencies through Agrobacterium-mediated transformation and protoplasts transfection with DNA or RNPs, and demonstrated that genome editing efficiency depends on the CRISPR/Cas9 delivery approach in potato.Delivery of the CRISPR/Cas9 components to the plant cells is a key step in its application as a genome editing tool. Here, we compared Agrobacterium-mediated transformation and protoplast transfection with CRISPR/Cas9 components for potato genome editing. Two sgRNAs were designed to simultaneously direct Cas9 to the StPPO2 gene encoding for a tuber polyphenol oxidase (PPO). A binary vector (CR-PPO) was utilized for either Agrobacterium-mediated transformation or for transient expression in protoplasts, while ribonucleoprotein complexes (RNP-PPO) were additionally assayed in protoplasts. Editing efficiency varied, yielding 9.6%, 18.4% and 31.9% of edited lines from Agrobacterium-mediated transformation, RNP-PPO and CR-PPO transient expression in protoplasts, respectively. Furthermore, only the CR-PPO transient expression resulted in lines edited in all four StPPO2 alleles, observed in 46% of the edited lines and confirmed by tuber PPO activity and enzymatic browning analysis. Lines with on-target DNA insertions were found from all three approaches and characterized by sequencing. The dual-sgRNA strategy resulted in a low incidence of the targeted deletion, likely due to contrasting efficiencies between sgRNAs, that was partially evident in the in silico analysis. Our results demonstrate that gene editing efficiency in potato depends on the CRISPR/Cas9 delivery strategy and provide insights to consider when selecting the appropriate methodology.
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| 13. |
- Andersson, Mariette
(författare)
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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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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 162, s. 1337-1358
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Tidskriftsartikel (refereegranskat)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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| 14. |
- Andersson, Mariette, et al.
(författare)
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CRISPR/Cas9 Technology for Potato Functional Genomics and Breeding
- 2023
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Ingår i: Plant Genome Engineering : Methods and Protocols. - New York, NY : Springer US. - 9781071631300 ; :2653, s. 333–361-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Cultivated potato (Solanum tuberosum L.) is one of the most important staple food crops worldwide. Its tetraploid and highly heterozygous nature poses a great challenge to its basic research and trait improvement through traditional mutagenesis and/or crossbreeding. The establishment of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) as a gene editing tool has allowed the alteration of specific gene sequences and their concomitant gene function, providing powerful technology for potato gene functional analysis and improvement of elite cultivars. This technology relies on a short RNA molecule called single guide RNA (sgRNA) that directs the Cas9 nuclease to induce a site-specific double-stranded break (DSB). Further, repair of the DSB by the error-prone non-homologous end joining (NHEJ) mechanism leads to the introduction of targeted mutations, which can be used to produce the loss of function of specific gene(s). In this chapter, we describe experimental procedures to apply the CRISPR/Cas9 technology for potato genome editing. First, we provide strategies for target selection and sgRNA design and describe a Golden Gate-based cloning system to obtain a sgRNA/Cas9-encoding binary vector. We also describe an optimized protocol for ribonucleoprotein (RNP) complex assembly. The binary vector can be used for both Agrobacterium-mediated transformation and transient expression in potato protoplasts, while the RNP complexes are intended to obtain edited potato lines through protoplast transfection and plant regeneration. Finally, we describe procedures to identify the gene-edited potato lines. The methods described here are suitable for potato gene functional analysis and breeding.
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| 15. |
- Andersson, Mariette
(författare)
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Development of Transgenic Potatoes to Attain Novel Starch Qualities
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Starch is a plant-derived polysaccharide with many uses in different food and non-food applications. In this thesis, the production of two novel potato starch qualities, amylopectin and high-amylose, and the modifications and the characteristics of the produced plants and starches are described. The novel potato starch qualities will find uses in e.g. the paper, adhesive, textile and packing industries. Amylopectin potato lines were produced by antisense inhibition of a single gene, coding for a granule-bound starch synthase (GBSS). One amylopectin line, EH92-527-1, is currently in an approval phase in the form of a European market notification. EH92-527-1 has been thoroughly characterised and molecular and chemical data for the line are presented. During the characterisation it was found that the antisense gene had been rearranged upon insertion, creating a truncated asymmetric inverted repeat. The inverted repeat is probably what is yielding the very efficient GBSS inhibition. The line was also shown to have an increased vitamin C level compared with the parental variety, probably due to an alteration in the sugar metabolism in the line. One issue often debated concerning genetically modified plants is the use of a selection gene transformed together with the trait gene/genes to be able to select for transgenic lines. A neomycin phosphotransferase gene (nptII), coding for a protein giving the plant resistance to the antibiotic kanamycin, is almost exclusively used as selection system during potato transformation. A non-antibiotic selection system based on a mutated acetohydroxyacid synthase (AHAS) and herbicides of the imidazolinone family was developed, yielding a higher transformation rate than when nptII is used. In contrast to amylopectin potatoes, the expression of two genes, coding for starch branching enzymes (SBE), had to be down-regulated to produce the required high-amylose potato starch. The starch had up to 7 times lower branching degree and a major increase in the amount of bound phosphate compared with the parental line. High-amylose lines were first produced by antisense inhibition of the two sbe genes but the frequency of lines with high-amylose starch quality was very low. To improve this, an RNA interference (RNAi) method was developed, which yielded a 10-fold higher frequency of inhibited lines. Another major advantage found with the RNAi method was a reduction in the number of T-DNA inserts compared with the previously used antisense technique. One disadvantage of the high-amylose lines is a reduction in starch yield. To increase the starch content in the high-amylose lines two novel genes, coding for Solanum tuberosum glycogenin homologue proteins (StGH) with a possible starch initiation function, were over-expressed in potato.
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| 16. |
- Andersson, Mariette, et al.
(författare)
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Efficient targeted multiallelic mutagenesis in tetraploid potato (Solanum tuberosum) by transient CRISPR-Cas9 expression in protoplasts
- 2017
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 0721-7714 .- 1432-203X. ; 36, s. 117-128
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Tidskriftsartikel (refereegranskat)abstract
- Altered starch quality with full knockout of GBSS gene function in potato was achieved using CRISPR-Cas9 technology, through transient transfection and regeneration from isolated protoplasts.Site-directed mutagenesis (SDM) has shown great progress in introducing precisely targeted mutations. Engineered CRISPR-Cas9 has received increased focus compared to other SDM techniques, since the method is easily adapted to different targets. Here, we demonstrate that transient application of CRISPR-Cas9-mediated genome editing in protoplasts of tetraploid potato (Solanum tuberosum) yielded mutations in all four alleles in a single transfection, in up to 2 % of regenerated lines. Three different regions of the gene encoding granule-bound starch synthase (GBSS) were targeted under different experimental setups, resulting in mutations in at least one allele in 2-12 % of regenerated shoots, with multiple alleles mutated in up to 67 % of confirmed mutated lines. Most mutations resulted in small indels of 1-10 bp, but also vector DNA inserts of 34-236 bp were found in 10 % of analysed lines. No mutations were found in an allele diverging one bp from a used guide sequence, verifying similar results found in other plants that high homology between guide sequence and target region near the protospacer adjacent motif (PAM) site is essential. To meet the challenge of screening large numbers of lines, a PCR-based high-resolution fragment analysis method (HRFA) was used, enabling identification of multiple mutated alleles with a resolution limit of 1 bp. Full knockout of GBSS enzyme activity was confirmed in four-allele mutated lines by phenotypic studies of starch. One remaining wild-type (WT) allele was shown sufficient to maintain enough GBSS enzyme activity to produce significant amounts of amylose.
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| 17. |
- 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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| 18. |
- Andersson, Mariette, et al.
(författare)
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Inhibition of plastid PPase and NTT leads to major changes in starch and tuber formation in potato
- 2018
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 69, s. 1913-1924
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Tidskriftsartikel (refereegranskat)abstract
- The importance of a plastidial soluble inorganic pyrophosphatase (psPPase) and an ATP/ ADP translocator (NTT) for starch composition and tuber formation in potato (Solanum tuberosum) was evaluated by individual and simultaneous down-regulation of the corresponding endogenous genes. Starch and amylose content of the transgenic lines were considerably lower, and granule size substantially smaller, with down-regulation of StpsPPase generating the most pronounced effects. Single-gene down-regulation of either StpsPPase or StNTT resulted in increased tuber numbers per plant and higher fresh weight yield. In contrast, when both genes were inhibited simultaneously, some lines developed only a few, small and distorted tubers. Analysis of metabolites revealed altered amounts of sugar intermediates, and a substantial increase in ADP-glucose content of the StpsPPase lines. Increased amounts of intermediates of vitamin C biosynthesis were also observed. This study suggests that hydrolysis of pyrophosphate (PPi) by action of a psPPase is vital for functional starch accumulation in potato tubers and that no additional mechanism for consuming, hydrolysing, or exporting PPi exists in the studied tissue. Additionally, it demonstrates that functional PPi hydrolysis in combination with efficient ATP import is essential for tuber formation and development.
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| 19. |
- Andersson, Mariette
(författare)
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Plant genome engineering from lab to field-a Keystone Symposia report
- 2021
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1506, s. 35-54
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Tidskriftsartikel (refereegranskat)abstract
- Facing the challenges of the world's food sources posed by a growing global population and a warming climate will require improvements in plant breeding and technology. Enhancing crop resiliency and yield via genome engineering will undoubtedly be a key part of the solution. The advent of new tools, such as CRIPSR/Cas, has ushered in significant advances in plant genome engineering. However, several serious challenges remain in achieving this goal. Among them are efficient transformation and plant regeneration for most crop species, low frequency of some editing applications, and high attrition rates. On March 8 and 9, 2021, experts in plant genome engineering and breeding from academia and industry met virtually for the Keystone eSymposium "Plant Genome Engineering: From Lab to Field" to discuss advances in genome editing tools, plant transformation, plant breeding, and crop trait development, all vital for transferring the benefits of novel technologies to the field.
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| 20. |
- Andersson, Mariette, et al.
(författare)
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Reduced Enzymatic Browning in Potato Tubers by Specific Editing of a Polyphenol Oxidase Gene via Ribonucleoprotein Complexes Delivery of the CRISPR/Cas9 System
- 2020
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Polyphenol Oxidases (PPOs) catalyze the conversion of phenolic substrates to quinones, leading to the formation of dark-colored precipitates in fruits and vegetables. This process, known as enzymatic browning, is the cause of undesirable changes in organoleptic properties and the loss of nutritional quality in plant-derived products. In potato (Solanum tubersoum L.), PPOs are encoded by a multi-gene family with different expression patterns. Here, we have studied the application of the CRISPR/Cas9 system to induce mutations in the StPPO2 gene in the tetraploid cultivar Desiree. We hypothesized that the specific editing of this target gene would result in a lower PPO activity in the tuber with the consequent reduction of the enzymatic browning. Ribonucleoprotein complexes (RNPs), formed by two sgRNAs and Cas9 nuclease, were transfected to potato protoplasts. Up to 68% of regenerated plants contained mutations in at least one allele of the target gene, while 24% of edited lines carried mutations in all four alleles. No off-target mutations were identified in other analyzed StPPO genes. Mutations induced in the four alleles of StPPO2 gene, led to lines with a reduction of up to 69% in tuber PPO activity and a reduction of 73% in enzymatic browning, compared to the control. Our results demonstrate that the CRISPR/Cas9 system can be applied to develop potato varieties with reduced enzymatic browning in tubers, by the specific editing of a single member of the StPPO gene family.
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| 21. |
- Andersson, Mariette
(författare)
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Structurally divergent lysophosphatidic acid acyltransferases with high selectivity for saturated medium chain fatty acids from Cuphea seeds
- 2015
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Ingår i: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 84, s. 1021-1033
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Tidskriftsartikel (refereegranskat)abstract
- Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn-2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Delta 9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn-2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed-specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed-specific LPAT from the bacterial-type class B. The activities of these enzymes were characterized in Camelina sativa by seed-specific co-expression with cDNAs for various Cuphea FatB acyl-acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium-chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10: 0 fatty acids in the Camelina sativa TAG sn-2 position, indicating a 10: 0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14: 0 at the sn-2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities.
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| 22. |
- Andersson, Mariette, et al.
(författare)
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Targeted gene suppression by RNA interference: An efficient method for production of high-amylose potato lines
- 2006
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 123:2, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- Production of high-amylose potato lines can be achieved by inhibition of two genes coding for starch branching enzymes. The use of antisense technology for gene inhibition have yielded a low frequency of high-amylose lines that mostly was correlated with high numbers of integrated T-DNA copies. To investigate whether the production of high-amylose lines could be improved, RNA interference was used for gene inhibition of the genes Sbe1 and Sbe2. Two constructs with 100 bp segments (pHAS2) or 200 bp segments (pHAS3) of both branching enzyme genes were cloned as inverted repeats controlled by a potato granule-bound starch synthase promoter. The construct pHAS3 was shown to be very efficient, yielding high-amylose quality in more than 50% of the transgenic lines. An antisense construct, included in the study as a comparator, resulted in only 3% of the transgenic lines being of high-amylose type. Noticeable was also that pHAS3 yielded low T-DNA copy inserts with an average of 83% of backbone-free transgenic lines being single copy events.
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| 23. |
- Andersson, Mariette, et al.
(författare)
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Tomato protoplasts as cell target for ribonucleoprotein (RNP)-mediated multiplexed genome editing
- 2021
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 144, s. 463-467
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to produce plants edited in multiple genes by means of DNA-free approaches opens new perspectives for breeding purposes and acceptance of resultant genotypes. In this work, we have explored the polyethylene glycol (PEG)-mediated delivery of ribonucleoproteins (RNPs) in tomato protoplasts using a multiplexing approach (i.e. two genes targeted simultaneously using two sgRNAs per gene) for the first time. We have analysed the editing outcome in fully developed green calli and demonstrated that tomato protoplasts are a valid cell target for RNP-mediated multiplexed genome editing with high efficiency.Key message RNP could be applied with high efficiency in a multiplexing genome editing approach in tomato protoplasts.
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| 24. |
- Bartek, Louise, et al.
(författare)
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Environmental benefits of circular food systems: The case of upcycled protein recovered using genome edited potato
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 380
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Tidskriftsartikel (refereegranskat)abstract
- Although essential in the human diet, large quantities of available protein are currently lost or under-utilized within the food system, including protein rich side streams from conventional potato starch production. By using the genome editing technique CRISPR-Cas9, conventional starch potato cultivars can be upgraded to facilitate high-value recovery of potato protein fit for human consumption. In turn, this could support the nessecary transition towards more circular food systems. The aim of this study was to assess what environmental benefits could be gained by shifting from conventional protein recovery practice to a novel approach using genome edited potato. Our results, using consequential life cycle assessment, showed that the novel protein recovery scenario provided substantial environmental savings for every ton potato starch produced, with a reduction in global warming impact, terrestrial acidification, land use and ecosystem damage of −720 kgCO2eq, −13 kgSO2eq, −760 m2a crop eq, and −1.1 × 10−5 species.yr respectively. The potential environmental benefits of using genome edited potato were maintained even when simulating reduced tuber yield, increased production inputs, and substitution of various protein sources. Although currently limited by EU legislation and technical maturity, high-value protein recovery from food side streams holds a promising potential to support sustainable production and circularity within the food system.
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| 25. |
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| 26. |
- Fält, Ann-Sofie, et al.
(författare)
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Protoplast-Based Method for Genome Editing in Tetraploid Potato
- 2021
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Ingår i: Crop Breeding : Genetic Improvement Methods. - New York, NY : Springer US. - 9781071612002 ; :2264, s. 177-186
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Bokkapitel (refereegranskat)abstract
- The cultivated potato is tetraploid with four probably equivalent loci for each gene. A potato variety is furthermore commonly genetically heterogeneous and selected based on a beneficial genetic context which is maintained by clonal propagation. When introducing genetic changes by genome editing it is then desirable to achieve edits in all four loci for a certain gene target. This is in order to avoid crosses to achieve homozygosity for edited gene loci and at the same time reduce risk of inbreeding depression. In such a context transient transfection of protoplasts for the introduction of mutations, avoiding stable insertion of foreign DNA, would be very attractive. The protocol of this chapter has been shown to be applicable for the introduction of mutations by DNA vectors containing expression cassettes of TALEN, Cas9, and Cas9 deaminase fusions together with sgRNA expression cassettes on either single or separate vectors. Furthermore, the protoplast-based system has been shown to work very efficiently for mutations introduced by in vitro-produced and transfected RNP (ribonucleoprotein) complexes.
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| 27. |
- Hofvander, P, et al.
(författare)
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Field performance and starch characteristics of high-amylose potatoes obtained by antisense gene targeting of two branching enzymes
- 2004
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Ingår i: Plant Biotechnology Journal. - : Wiley. - 1467-7652 .- 1467-7644. ; 2:4, s. 311-320
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Tidskriftsartikel (refereegranskat)abstract
- Potato is an important crop for starch production, but there are limitations regarding the genetic variation of starch quality. in maize, starches with various properties have been available for a long time by mutational breeding. Amylose starch from potatoes differs from cereal amyloses in several functionally important aspects, such as a higher degree of polymerization. Areas of application in which the degree of polymerization is of importance include film forming and the polymeric properties of bioplastics. High-amylose potato lines have been achieved by inhibiting the two known branching enzyme forms of potato. A single inserted gene construct for the inhibition of both forms resulted in structural changes of the starch to levels of branching that were below the commercially available amylose standards of potato. The high-amylose potato lines were tested in multiple year field trials of agronomic performance and were used for the pilot plant production of starch. The introduced trait was confirmed to be stable over multiple years. The consequences of the modification were found to be an increased tuber yield, reduced starch content, smaller granule size and an increase in reducing sugars.
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| 28. |
- Hofvander, Per, et al.
(författare)
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Potato trait development going fast-forward with genome editing
- 2022
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Ingår i: Trends in Genetics. - : Elsevier BV. - 0168-9525. ; 38, s. 218-221
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Tidskriftsartikel (refereegranskat)abstract
- Implementations and improvements of genome editing techniques used in plant science have increased exponentially. For some crops, such as potato, the use of transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR) has moved to the next step of trait development and field trials, and should soon be applied to commercial cultivation.
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| 29. |
- Hofvander, Per, et al.
(författare)
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Potato tuber expression of Arabidopsis WRINKLED1 increase triacylglycerol and membrane lipids while affecting central carbohydrate metabolism
- 2016
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Ingår i: Plant Biotechnology Journal. - : Wiley. - 1467-7644 .- 1467-7652. ; 14, s. 1883-1898
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Tidskriftsartikel (refereegranskat)abstract
- Tuber and root crops virtually exclusively accumulate storage products in the form of carbohydrates. An exception is yellow nutsedge (Cyperus esculentus) in which tubers have the capacity to store starch and triacylglycerols (TAG) in roughly equal amounts. This suggests that a tuber crop can efficiently handle accumulation of energy dense oil. From a nutritional as well as economic aspect, it would be of interest to utilize the high yield capacity of tuber or root crops for oil accumulation similar to yellow nutsedge. The transcription factor WRINKLED1 from Arabidopsis thaliana, which in seed embryos induce fatty acid synthesis, has been shown to be a major factor for oil accumulation. WRINKLED1 was expressed in potato (Solanum tuberosum) tubers to explore whether this factor could impact tuber metabolism. This study shows that a WRINKLED1 transcription factor could induce triacylglycerol accumulation in tubers of transformed potato plants grown in field (up to 12 nmol TAG/mg dry weight, 1% of dry weight) together with a large increase in polar membrane lipids. The changes in metabolism further affected starch accumulation and composition concomitant with massive increases in sugar content.
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| 30. |
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| 31. |
- Liu, Ying, et al.
(författare)
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Establishment of a DNA-free genome editing and protoplast regeneration method in cultivated tomato (Solanum lycopersicum)
- 2022
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 0721-7714 .- 1432-203X.
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Tidskriftsartikel (refereegranskat)abstract
- Key message We have established a DNA-free genome editing method via ribonucleoprotein-based CRISPR/Cas9 in cultivated tomato and obtained mutant plants regenerated from transfected protoplasts with a high mutation rate. The application of genome editing as a research and breeding method has provided many possibilities to improve traits in many crops in recent years. In cultivated tomato (Solanum lycopersicum), so far only stable Agrobacterium-mediated transformation carrying CRISPR/Cas9 reagents has been established. Shoot regeneration from transfected protoplasts is the major bottleneck in the application of DNA-free genome editing via ribonucleoprotein-based CRISPR/Cas9 method in cultivated tomato. In this study, we report the implementation of a transgene-free breeding method for cultivated tomato by CRISPR/Cas9 technology, including the optimization of protoplast isolation and overcoming the obstacle in shoot regeneration from transfected protoplasts. We have identified that the shoot regeneration medium containing 0.1 mg/L IAA and 0.75 mg/L zeatin was the best hormone combination with a regeneration rate of up to 21.3%. We have successfully obtained regenerated plants with a high mutation rate four months after protoplast isolation and transfection. Out of 110 regenerated M-0 plants obtained, 35 (31.8%) were mutated targeting both SP and SP5G genes simultaneously and the editing efficiency was up to 60% in at least one allele in either SP or SP5G genes.
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| 32. |
- Muneer, Faraz, et al.
(författare)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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| 33. |
- Muneer, Faraz, et al.
(författare)
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Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties
- 2015
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 16:3, s. 695-705
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.
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| 34. |
- Nicolia, Alessandro, et al.
(författare)
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Targeted gene mutation in tetraploid potato through transient TALEN expression in protoplasts
- 2015
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 204, s. 17-24
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Tidskriftsartikel (refereegranskat)abstract
- Potato is the third largest food crop in the world, however, the high degree of heterozygosity, the tetrasomic inheritance and severe inbreeding depression are major difficulties for conventional potato breeding. The rapid development of modern breeding methods offers new possibilities to enhance breeding efficiency and precise improvement of desirable traits. New site-directed mutagenesis techniques that can directly edit the target genes without any integration of recombinant DNA are especially favorable. Here we present a successful pipeline for site-directed mutagenesis in tetraploid potato through transient TALEN expression in protoplasts. The transfection efficiency of protoplasts was 38-39% and the site-directed mutation frequency was 7-8% with a few base deletions as the predominant type of mutation. Among the protoplast-derived calli, 11-13% showed mutations and a similar frequency (10%) was observed in the regenerated shoots. Our results indicate that the site-directed mutagenesis technology could be used as a new breeding method in potato as well as for functional analysis of important genes to promote sustainable potato production. (C) 2015 Elsevier B.V. All rights reserved.
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| 35. |
- Pourazari, Fereshteh, et al.
(författare)
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Altered Tuber Yield in Genetically Modified High-Amylose and Oil Potato Lines Is Associated With Changed Whole-Plant Nitrogen Economy
- 2018
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Breeding for improved crop quality traits can affect non-target traits related to growth and resource use, and these effects may vary in different cultivation conditions (e.g., greenhouse vs. field). The objectives of this study are to investigate the growth and whole-plant nitrogen (N) economy of two genetically modified (GM) potato lines compared to their non-GM parental varieties and when grown in different cultivation conditions. A high-amylose GM potato line and its parent were grown under field and greenhouse conditions for one growing season in Sweden; and a GM oil potato line and its parent were grown in greenhouse conditions only. Tuber yield, above ground biomass, N uptake efficiency and other plant N economy traits were assessed. In both cultivation conditions, the GM lines produced between 1.5 and two times more tubers as compared with their parents. In the greenhouse, fresh tuber yield and N uptake efficiency were unaffected by the genetic modifications, but the GM-lines produced less tuber biomass per plant-internal N compared to their parents. In the field, the fresh tuber yield was 40% greater in the high-amylose line as compared with its parent; the greater fresh tuber yield in the high-amylose GM line was accomplished by higher water allocation to the harvested tubers, and associated with increased N recovery from soil (+20%), N uptake efficiency (+53%), tuber N content (+20%), and N accumulation (+120%) compared with the non-GM parent. The cultivation conditions influenced the yield and N economy. For example, the final fresh above-ground plant biomass and N pool were considerably higher in the greenhouse conditions, whilst the tuber yield was higher in the field conditions. In conclusion, the genetic modification inducing high accumulation of amylose in potato tubers affected several non-target traits related to plant N economy, and increased the plant N uptake and accumulation efficiency of the field-grown plants. Due to strongly increased plant N accumulation compared to the parental variety, the cultivation of the high-amylose line is expected to require higher N fertilization rates. However, starch productivity per unit land area or soil N still is expected to be higher in the high-amylose line.
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| 36. |
- Selga, Catja, et al.
(författare)
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Diversity and population structure of Nordic potato cultivars and breeding clones
- 2022
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- Background: The genetic diversity and population structure of breeding germplasm is central knowledge for crop improvement. To gain insight into the genetic potential of the germplasm used for potato breeding in a Nordic breeding program as well as all available accessions from the Nordic genebank (NordGen), 133 potato genotypes were genotyped using the Infinium Illumina 20 K SNP array. After SNP filtering, 11 610 polymorphic SNPs were included in the analysis. In addition, data from three important breeding traits – percent dry matter and uniformity of tuber shape and eye – were scored to measure the variation potato cultivars and breeding clones.Results: The genetic diversity among the genotypes was estimated using principal coordinate analysis based on the genetic distance between individuals, as well as by using the software STRUCTURE. Both methods suggest that the collected breeding material and the germplasm from the gene‑bank are closely related, with a low degree of population structure between the groups. The phenotypic distribution among the genotypes revealed significant differences, especially between farmer’s cultivars and released cultivars and breeding clones. The percent heterozygosity was similar between the groups, with a mean average of 58–60%. Overall, the breeding germplasm and the acces‑ sions from the Nordic genebank seems to be closely related with similar genetic background.Conclusion: The genetic potential of available Nordic potato breeding germplasm is low, and for genetic hybridiza‑ tion purposes, genotypes from outside the Nordic region should be employed.
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| 37. |
- Sharma, Shrikant, et al.
(författare)
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Pho1a (plastid starch phosphorylase) is duplicated and essential for normal starch granule phenotype in tubers of Solanum tuberosum L
- 2023
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Ingår i: Frontiers in Plant Science. - 1664-462X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Reserve starch from seeds and tubers is a crucial plant product for human survival. Much research has been devoted to quantitative and qualitative aspects of starch synthesis and its relation to abiotic factors of importance in agriculture. Certain aspects of genetic factors and enzymes influencing carbon assimilation into starch granules remain elusive after many decades of research. Starch phosphorylase (Pho) can operate, depending on metabolic conditions, in a synthetic and degradative pathway. The plastidial form of the enzyme is one of the most highly expressed genes in potato tubers, and the encoded product is imported into starch-synthesizing amyloplasts. We identified that the genomic locus of a Pho1a-type starch phosphorylase is duplicated in potato. Our study further shows that the enzyme is of importance for a normal starch granule phenotype in tubers. Null mutants created by genome editing display rounded starch granules in an increased number that contained a reduced ratio of apparent amylose in the starch.
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| 38. |
- Turesson, Helle, et al.
(författare)
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Starch biosynthetic genes and enzymes are expressed and active in the absence of starch accumulation in sugar beet tap-root
- 2014
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background: Starch is the predominant storage compound in underground plant tissues like roots and tubers. An exception is sugar beet tap-root (Beta vulgaris ssp altissima) which exclusively stores sucrose. The underlying mechanism behind this divergent storage accumulation in sugar beet is currently not fully known. From the general presence of starch in roots and tubers it could be speculated that the lack in sugar beet tap-roots would originate from deficiency in pathways leading to starch. Therefore with emphasis on starch accumulation, we studied tap-roots of sugar beet using parsnip (Pastinaca sativa) as a comparator. Results: Metabolic and structural analyses of sugar beet tap-root confirmed sucrose as the exclusive storage component. No starch granules could be detected in tap-roots of sugar beet or the wild ancestor sea beet (Beta vulgaris ssp. maritima). Analyses of parsnip showed that the main storage component was starch but tap-root tissue was also found to contain significant levels of sugars. Surprisingly, activities of four main starch biosynthetic enzymes, phosphoglucomutase, ADP-glucose pyrophosphorylase, starch synthase and starch branching enzyme, were similar in sugar beet and parsnip tap-roots. Transcriptional analysis confirmed expression of corresponding genes. Additionally, expression of genes involved in starch accumulation such as for plastidial hexose transportation and starch tuning functions could be determined in tap-roots of both plant species. Conclusion: Considering underground storage organs, sugar beet tap-root upholds a unique property in exclusively storing sucrose. Lack of starch also in the ancestor sea beet indicates an evolved trait of biological importance. Our findings in this study show that gene expression and enzymatic activity of main starch biosynthetic functions are present in sugar beet tap-root during storage accumulation. In view of this, the complete lack of starch in sugar beet tap-roots is enigmatic.
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