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- Aad, G., et al.
(författare)
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- 2015
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :8
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Tidskriftsartikel (refereegranskat)
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| 13. |
- Aad, G., et al.
(författare)
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- 2015
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Tidskriftsartikel (refereegranskat)
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- Hollestelle, Antoinette, et al.
(författare)
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No clinical utility of KRAS variant rs61764370 for ovarian or breast cancer
- 2016
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 141:2, s. 386-401
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Tidskriftsartikel (refereegranskat)abstract
- Objective Clinical genetic testing is commercially available for rs61764370, an inherited variant residing in a KRAS 3′ UTR microRNA binding site, based on suggested associations with increased ovarian and breast cancer risk as well as with survival time. However, prior studies, emphasizing particular subgroups, were relatively small. Therefore, we comprehensively evaluated ovarian and breast cancer risks as well as clinical outcome associated with rs61764370. Methods Centralized genotyping and analysis were performed for 140,012 women enrolled in the Ovarian Cancer Association Consortium (15,357 ovarian cancer patients; 30,816 controls), the Breast Cancer Association Consortium (33,530 breast cancer patients; 37,640 controls), and the Consortium of Modifiers of BRCA1 and BRCA2 (14,765 BRCA1 and 7904 BRCA2 mutation carriers). Results We found no association with risk of ovarian cancer (OR = 0.99, 95% CI 0.94-1.04, p = 0.74) or breast cancer (OR = 0.98, 95% CI 0.94-1.01, p = 0.19) and results were consistent among mutation carriers (BRCA1, ovarian cancer HR = 1.09, 95% CI 0.97-1.23, p = 0.14, breast cancer HR = 1.04, 95% CI 0.97-1.12, p = 0.27; BRCA2, ovarian cancer HR = 0.89, 95% CI 0.71-1.13, p = 0.34, breast cancer HR = 1.06, 95% CI 0.94-1.19, p = 0.35). Null results were also obtained for associations with overall survival following ovarian cancer (HR = 0.94, 95% CI 0.83-1.07, p = 0.38), breast cancer (HR = 0.96, 95% CI 0.87-1.06, p = 0.38), and all other previously-reported associations. Conclusions rs61764370 is not associated with risk of ovarian or breast cancer nor with clinical outcome for patients with these cancers. Therefore, genotyping this variant has no clinical utility related to the prediction or management of these cancers.
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| 19. |
- Abrahamsson, Malin, et al.
(författare)
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Degeneration pattern in somatic embryos of Pinus sylvestris L.
- 2017
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Ingår i: In Vitro Cellular and Developmental Biology - Plant. - : Springer Science and Business Media LLC. - 1054-5476 .- 1475-2689. ; 53, s. 86-96
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Tidskriftsartikel (refereegranskat)abstract
- Somatic embryos can be used for propagating forest trees vegetatively, which is of great importance for capturing the genetic gain in breeding programs. However, many economically important Pinus species are difficult or impossible to propagate via somatic embryogenesis. In order to get a better understanding of the difficulties to propagate Pinus species via somatic embryogenesis, we are studying the developmental pathway of somatic embryos in different cell lines. In a previous study, we showed that the morphology of early somatic embryos in Scots pine (Pinus sylvestris) differs between cell lines giving rise to normal or abnormal cotyledonary embryos. In this study, we have compared the proliferation and degeneration pattern of early and late embryos in a normal and abnormal cell line. In both cell lines, a high frequency of the embryos degenerated. Among the degenerating embryos, two main degeneration patterns could be distinguished. In the normal cell line, the embryos degenerated similar to how the subordinate embryos are degraded in the seed. In the abnormal cell line, the degeneration of the embryos resulted in a continuous loop of embryo degeneration and differentiation of new embryos. We observed a similar degeneration pattern when embryogenic tissue was initiated from megagametophytes containing zygotic embryos at the stage of cleavage polyembryony. Based on our results, we suggest that the degeneration pattern in abnormal cell lines starts during initiation of embryogenic cultures.
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| 20. |
- Abrahamsson, Malin, et al.
(författare)
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Patterning during somatic embryogenesis in Scots pine in relation to polar auxin transport and programmed cell death
- 2012
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 109, s. 391-400
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Tidskriftsartikel (refereegranskat)abstract
- Somatic embryogenesis is a useful tool to propagate conifers vegetatively. However, a major limitation in many pine species is the low quality of cotyledonary somatic embryos. The aim of this study has been to elucidate the developmental pathway of somatic embryos in Scots pine (Pinus sylvestris), to identify deviations from the normal pathway and to identify processes that might disturb normal development. Initially we compared the developmental pathway of somatic embryogenesis in representative cell lines yielding cotyledonary embryos with normal and abnormal morphology. Early embryos carrying suspensor cells in excess of the normal number (supernumerary) were more frequent in cell lines giving rise to abnormal cotyledonary embryos. In this study we show that the frequency of early somatic embryos with supernumerary suspensor cells increased after treatment with the auxin transport inhibitor 1-N-naphtylphthalamic acid (NPA). Furthermore, the yield of developing embryos increased significantly after treatment with the antiauxin 2-(4-chlorophenoxy)-2-methylpropionic acid (PCIB), but the morphology of the embryos was not affected. The number of cells undergoing PCD was analyzed using a TUNEL-assay. The frequency of TUNEL-positive cells was high both in proliferating cultures and during differentiation of early somatic embryos. However, the pattern of TUNEL-positive cells was similar in normal somatic embryos and in embryos with supernumerary suspensor cells. Together our results suggest that the presence of supernumerary suspensor cells in early somatic embryos of Scots pine is caused by disturbed polar auxin transport and results in aberrant embryo development.
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| 21. |
- Abrahamsson, Malin, et al.
(författare)
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Somatic Embryogenesis in Scots Pine (Pinus sylvestris L.)
- 2018
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Ingår i: STEP WISE PROTOCOLS FOR SOMATIC EMBRYOGENESIS OF IMPORTANT WOODY PLANTS, VOL I, 2ND EDITION. - Cham : Springer International Publishing. - 9783319894829 ; 84:84, s. 123-133
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Bokkapitel (refereegranskat)abstract
- Scots pine (Pinus sylvestris L.) can be propagated via somatic embryogenesis. However, the protocols available today are not sufficient for large-scale propagation. The method needs to be optimized in order to increase the initiation frequency of embryogenic cell lines giving rise to high quality cotyledonary embryos, and to improve somatic embryo germination. Protocols presented in this chapter have been used to carry out fundamental research, where the resulting knowledge will be valuable for improving culture conditions for large scale propagation of Pinus species via somatic embryogenesis.
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| 22. |
- Alvarez, José M, et al.
(författare)
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The WUSCHEL-RELATED HOMEOBOX 3 gene PaWOX3 regulates lateral organ formation in Norway spruce
- 2015
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:4, s. 1078-1088
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Tidskriftsartikel (refereegranskat)abstract
- In angiosperms, WUSCHEL-RELATED HOMEOBOX 3 (WOX3) genes are required for the recruitment of founder cells from the lateral domains of shoot meristems that form lateral regions of leaves. However, the regulation of the formation of lateral organs in gymnosperms remains unknown. By using somatic embryos of Norway spruce ( Picea abies) we have studied the expression and function of PaWOX3 during embryo development. The mRNA abundance of PaWOX3 was determined by quantitative real-time PCR, and the spatial expression of PaWOX3 was analysed by histochemical beta-glucuronidase (GUS) assays and in situ mRNA hybridization. To investigate the function of PaWOX3, we analysed how downregulation of PaWOX3 in RNA interference lines affected embryo development and morphology. PaWOX3 was highly expressed in mature embryos at the base of each cotyledon close to the junction between the cotyledons, and in the lateral margins of cotyledons and needles, separating them into an adaxial and an abaxial side. Downregulation of the expression of PaWOX3 caused defects in lateral margin outgrowth in cotyledons and needles, and reduced root elongation. Our data suggest that the WOX3 function in margin outgrowth in lateral organs is conserved among the seed plants, whereas its function in root elongation may be unique to gymnosperms.
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| 25. |
- Berlin Kolm, Sofia, et al.
(författare)
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High-density linkage mapping and evolution of paralogs and orthologs in Salix and Populus
- 2010
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 11:1, s. 129-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Salix (willow) and Populus (poplar) are members of the Salicaceae family and they share many ecological as well as genetic and genomic characteristics. The interest of using willow for biomass production is growing, which has resulted in increased pressure on breeding of high yielding and resistant clones adapted to different environments. The main purpose of this work was to develop dense genetic linkage maps for mapping of traits related to yield and resistance in willow. We used the Populus trichocarpa genome to extract evenly spaced markers and mapped the orthologous loci in the willow genome. The marker positions in the two genomes were used to study genome evolution since the divergence of the two lineages some 45 mya. RESULTS: We constructed two linkage maps covering the 19 linkage groups in willow. The most detailed consensus map, S1, contains 495 markers with a total genetic distance of 2477 cM and an average distance of 5.0 cM between the markers. The S3 consensus map contains 221 markers and has a total genetic distance of 1793 cM and an average distance of 8.1 cM between the markers. We found high degree of synteny and gene order conservation between willow and poplar. There is however evidence for two major interchromosomal rearrangements involving poplar LG I and XVI and willow LG Ib, suggesting a fission or a fusion in one of the lineages, as well as five intrachromosomal inversions. The number of silent substitutions were three times lower (median: 0.12) between orthologs than between paralogs (median: 0.37 - 0.41). CONCLUSIONS: The relatively slow rates of genomic change between willow and poplar mean that the genomic resources in poplar will be most useful in genomic research in willow, such as identifying genes underlying QTLs of important traits. Our data suggest that the whole-genome duplication occurred long before the divergence of the two genera, events which have until now been regarded as contemporary. Estimated silent substitution rates were 1.28 x 10-9 and 1.68 x 10-9 per site and year, which are close to rates found in other perennials but much lower than rates in annuals.
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| 36. |
- Hakman, Inger, et al.
(författare)
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Isolation and growth of protoplasts from suspensions of Pinus contorta Dougl. ex Loud.
- 1983
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Ingår i: Plant Cell Reports. ; 2:2, s. 92-94
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Tidskriftsartikel (refereegranskat)abstract
- Cell suspensions were initiated from embryo derived calli of Pinus contorta. Some of these cell lines could be maintained in culture for at least one year without reduced growth. A high yield of protoplasts was obtained from the cell suspensions. The protoplasts started to divide after two days and cell clusters could be observed after about two weeks. The growth phase of the cell suspensions was very important for the division of protoplasts. Only protoplasts isolated from suspensions in an actively dividing phase were able to divide with a high frequency and to give rise to cell clusters.
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| 37. |
- Hakman, Inger, et al.
(författare)
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Somatic embryogenesis and plant regeneration from suspension cultures of Picea glauca (White spruce).
- 1988
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317. ; 72:3, s. 579-587.
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Tidskriftsartikel (refereegranskat)abstract
- Plantlets were regenerated from long-term embryogenic cultures of Picea glauca (Moench) Voss. (White spruce). Embryogenic calli, initiated from immature zygotic embryos and maintained by monthly subculture for 16 months, were used to establish suspension cultures. Small somatic embryos were continuously produced in liquid culture medium containing auxin and cytokinin and the cultures showed a sustained regeneration capacity for >6 months. Somatic embryos propagated in the suspension cultures developed further into embryos bearing cotyledons, about 1 month after transfer to solidified medium containing abscisic acid. Electron microscopic examination revealed that storage nutrients, lipids, proteins and carbohydrates, accumulated in the somatic embryos during this treatment with abscisic acid (ABA). Upon subculture to medium lacking plant growth regulators such embryos could develop into small green plantlets.
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| 38. |
- Hedman, Harald, et al.
(författare)
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Analysis of the WUSCHEL-RELATED HOMEOBOX gene family in the conifer picea abies reveals extensive conservation as well as dynamic patterns
- 2013
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions: Our study shows that all major radiations within the WOX gene family took place before the angiosperm-gymnosperm split and that there has been a recent expansion within the intermediate clade in the Pinaceae family. Furthermore, we show that the genes from the intermediate clade are preferentially expressed during embryo development in Picea abies. Our data also indicates that there are clear orthologs of both WUS and WOX5 present in the P. abies genome.
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| 39. |
- Helmersson, Andreas, et al.
(författare)
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Embryogenic cell lines of Juniperus communis, easy establishment and embryo maturation, limited germination
- 2009
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 96, s. 211-217
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Tidskriftsartikel (refereegranskat)abstract
- Several coniferous species belonging to the Pinaceae family can be propagated via somatic embryogenesis, while species belonging to the Cupressaceae family cannot. The aim of this study was to identify possibilities and limitations with somatic embryogenesis in Cupressaceae. Juniperus communis was chosen as model species. We show that a high initiation frequency of embryogenic cell lines can be established from intact megagametophytes at the time when intensive cleavage polyembryogeny takes place. The embryogenic cell lines proliferate fast on medium lacking plant growth regulators. Early somatic embryos develop after transfer to medium with decreased content of nitrogen and calcium. The early embryos mature after exposure to abscisic acid. Mature cotyledonary embryos germinate after partial desiccation. A high proportion, over 40%, of the germinating embryos retain the embryogenic potential in the basal part, resulting in development of new embryogenic tissue
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| 40. |
- Högberg, Karl-Anders, et al.
(författare)
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Critical factors affecting ex vitro performance of somatic embryo plants of Picea abies
- 2001
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 16:4, s. 295-304
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The potential to use somatic embryos for large-scale propagation of elite genotypes, for integration into breeding programmes and for connecting breeding and mass propagation, is receiving much attention. However, before the methods are applied it is important that the plants regenerated via somatic embryogenesis grow as expected, i.e. as seedlings or cuttings. Growth of somatic embryo plants is under a cumulative influence of a number of treatments given during the in vitro phase and during the ex vitro establishment phase. The aim of this study was to identify treatments with a negative influence on the subsequent growth of somatic embryo plants of Norway spruce (Picea abies L. Karst.). Based on the results, the time of contact with abscisic acid during somatic embryo maturation and the length of continuous light treatment (CLT) during the first growth period strongly affect the height growth during two successive growth periods. In both cases longer treatments exerted negative effects. Based on these results a new method was set up, which includes: (1) prematuration treatment of the suspension culture in a growth regulator-free medium, by which the maturation step is synchronized and contracted; and (2) a two-phase germination treatment, first on a solidified medium and then in a liquid medium. This treatment avoids extended CLT during the first growth period. Another advantage of the two-phase germination treatment is a better root-system development. Somatic embryo plants produced according to this method can be transferred directly from in vitro conditions to the greenhouse.
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| 41. |
- Högberg, Karl-Anders, et al.
(författare)
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Field performance of Pinus contorta trees propagated vegetatively via adventitious buds
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:4, s. 318-321
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Tidskriftsartikel (refereegranskat)abstract
- Pinus contorta plants regenerated from adventitious buds induced on zygotic embryos were planted in a field trial where growth, straightness and flowering were followed over 7 years. Seedlings were taller than the plants derived from adventitious buds at the start of the field trial. Adventitious plants did not catch up with seedlings in height after 7 years in the field, but the relative height growth was equal. The higher frequency of plagiotropic growth that was displayed by adventitious plants the first year in the field was not reflected by differences in the frequency of basal sweeps 6 years later. However, the frequency of crooked stems was comparatively high but similar among the plant types. Flowering was more abundant for the seedlings than for adventitious plants. Taken together, the results show that P. contorta can be cloned via adventitious buds from zygotic embryos, and that the resulting plants show satisfactory growth for inclusion in breeding.
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| 42. |
- Kien, Nguyen Duc, et al.
(författare)
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Cellulose content as a selection trait in breeding for kraft pulp yield in Eucalyptus urophylla
- 2009
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Ingår i: Annals of Forest Science. - : Springer Science and Business Media LLC. - 1286-4560 .- 1297-966X. ; 66
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effectiveness of using cellulose content, measured by the diglyme-HCl method, as a selection trait in breeding programs for kraft pulp yield in Eucalyptus urophylla.A total of 275 trees from sixty-two families were sampled from a thinned progeny trial of E. urophylla in northern Vietnam to evaluate cellulose content from breast-height increment cores. Among those, twenty unrelated trees were felled to evaluate cellulose content and pulp yield from breast-height disk samples.The regression of pulp yield of disk samples on cellulose content was strong either from disks (R(2) = 0.83) or increment cores (R(2) = 0.69). There was no significant difference in cellulose content between the provenances. The narrow-sense within-provenance heritability of cellulose content was 0.50 and the coefficient of additive genetic variation was 3.9%. Genetic correlations between cellulose content and growth (0.28-0.45) or wood basic density (-0.02) were not significantly different from zero.Breast-height increment core cellulose content measured by diglyme-HCl method is under strong genetic control and can be used to rank trees for pulp yield in E. urophylla plantations. Selection for increased cellulose content would have only minor effects on growth and wood basic density.
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| 43. |
- Larsson, Emma, et al.
(författare)
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Differential regulation of Knotted1-like genes during establishment of the shoot apical meristem in Norway spruce (Picea abies)
- 2012
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 0721-7714 .- 1432-203X. ; 31, s. 1053-1060
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Tidskriftsartikel (refereegranskat)abstract
- Establishment of the shoot apical meristem (SAM) in Arabidopsis embryos requires the KNOXI transcription factor SHOOT MERISTEMLESS. In Norway spruce (Picea abies), four KNOXI family members (HBK1, HBK2, HBK3 and HBK4) have been identified, but a corresponding role in SAM development has not been demonstrated. As a first step to differentiate between the functions of the four Norway spruce HBK genes, we have here analyzed their expression profiles during the process of somatic embryo development. This was made both under normal embryo development and under conditions of reduced SAM formation by treatment with the polar auxin transport inhibitor NPA. Concomitantly with the formation of an embryonic SAM, the HBK2 and HBK4 genes displayed a significant up-regulation that was delayed by NPA treatment. In contrast, HBK1 and HBK3 were up-regulated prior to SAM formation, and their temporal expression was not affected by NPA. Ectopic expression of the four HBK genes in transgenic Arabidopsis plants further supported similar functions of HBK2 and HBK4, distinct from those of HBK1 and HBK3. Together, the results suggest that HBK2 and HBK4 exert similar functions related to the SAM differentiation and somatic embryo development in Norway spruce, while HBK1 and HBK3 have more general functions during embryo development.
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| 44. |
- Larsson, Emma, et al.
(författare)
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Expression of PaNAC01, a Picea abies CUP-SHAPED COTYLEDON orthologue, is regulated by polar auxin transport and associated with differentiation of the shoot apical meristem and formation of separated cotyledons
- 2012
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Ingår i: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 110, s. 923-934
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Tidskriftsartikel (refereegranskat)abstract
- During embryo development in most gymnosperms, the establishment of the shoot apical meristem (SAM) occurs concomitantly with the formation of a crown of cotyledons surrounding the SAM. It has previously been shown that the differentiation of cotyledons in somatic embryos of Picea abies is dependent on polar auxin transport (PAT). In the angiosperm model plant, Arabidopsis thaliana, the establishment of cotyledonary boundaries and the embryonal SAM is dependent on PAT and the expression of the CUP-SHAPED COTYLEDON (CUC) genes, which belong to the large NAC gene family. The aim of this study was to characterize CUC-like genes in a gymnosperm, and to elucidate their expression during SAM and cotyledon differentiation, and in response to PAT.Sixteen Picea glauca NAC sequences were identified in GenBank and deployed to different clades within the NAC gene family using maximum parsimony analysis and Bayesian inference. Motifs conserved between angiosperms and gymnosperms were analysed using the motif discovery tool MEME. Expression profiles during embryo development were produced using quantitative real-time PCR. Protein conservation was analysed by introducing a P. abies CUC orthologue into the A. thaliana cuc1cuc2 double mutant.Two full-length CUC-like cDNAs denoted PaNAC01 and PaNAC02 were cloned from P. abies. PaNAC01, but not PaNAC02, harbours previously characterized functional motifs in CUC1 and CUC2. The expression profile of PaNAC01 showed that the gene is PAT regulated and associated with SAM differentiation and cotyledon formation. Furthermore, PaNAC01 could functionally substitute for CUC2 in the A. thaliana cuc1cuc2 double mutant.The results show that CUC-like genes with distinct signature motifs existed before the separation of angiosperms and gymnosperms approx. 300 million years ago, and suggest a conserved function between PaNAC01 and CUC1/CUC2.
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| 45. |
- Lindroth, Anders M., et al.
(författare)
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Two S-adenosylmethionine synthetase-encoding genes that are differentially expressed during adventitious root development in Pinus Contorta
- 2001
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Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 46:3, s. 335-346
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Tidskriftsartikel (refereegranskat)abstract
- Two S-adenosylmethionine synthetase (SAMS) cDNAs, PcSAMS1 and PcSAMS2, have been identified in Pinus contorta. We found that the two genes are differentially expressed during root development. Thus, PcSAMS1 is preferentially expressed in roots and exhibits a specific expression pattern in the meristem at the onset of adventitious root development, whereas PcSAMS2 is expressed in roots as well as in shoots and is down-regulated during adventitious root formation. The expression of the two SAMS genes is different from the SAMS activity levels during adventitious root formation. We conclude that other SAMS genes that remain to be characterized may contribute to the observed SAMS activity, or that the activities of PcSAMS1 and PcSAMS2 are affected by post-transcriptional regulation. The deduced amino acid sequences of PcSAMS1 and PcSAMS2 are highly divergent, suggesting different functional roles. However, both carry the two perfectly conserved motifs that are common to all plant SAMS. At the protein level, PcSAMS2 shares about 90% identity to other isolated eukaryotic SAMS, while PcSAMS1 shares less than 50% identity with other plant SAMS. In a phylogenetic comparison, PcSAMS1 seems to have diverged significantly from all other SAMS genes. Nevertheless, PcSAMS1 was able to complement a Saccharomyces cerevisiae sam1 sam2 double mutant, indicating that it encodes a functional SAMS enzyme.
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| 46. |
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| 47. |
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| 48. |
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| 49. |
- Merino, Irene, et al.
(författare)
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Identification of molecular processes that differ among Scots pine somatic embryogenic cell lines leading to the development of normal or abnormal cotyledonary embryos
- 2018
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Ingår i: Tree Genetics and Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Several coniferous species can today be propagated through somatic embryogenesis, but for species belonging to the Pinus genus, there are still problems related to the small number of genotypes from which embryogenic cultures can be established and the low yield of high-quality cotyledonary embryos. In order to pinpoint molecular processes that might be disturbed during somatic embryogenesis in Scots pine, we have analyzed the expression pattern of selected transcripts during development of somatic embryos in a normal and an abnormal cell line of Scots pine. The selected transcripts have been previously shown to be differentially expressed during early zygotic embryogenesis in Scots pine (Merino et al. 2016). Based on the transcripts that accumulated differentially between the two cell lines, we conclude that the apical-basal polarization in early somatic embryos and the transition from the morphogenic phase to the maturation phase are disturbed in the abnormal cell line. A comparison between transcript accumulation during somatic and zygotic embryogenesis highlighted problems with the continuous embryo degeneration processes in embryogenic cultures of Scots pine. Transcripts that were highly abundant during the cleavage process in zygotic embryos showed different accumulation patterns during somatic embryogenesis in Scots pine compared to those in Norway spruce. Furthermore, altering the expression of these transcripts in embryogenic cultures of Norway spruce resulted in a changed proliferation pattern of the embryos so that they became more similar to proliferating somatic embryos of Scots pine. Taken together, our results provide a deeper understanding of the deviations in abnormal cell lines and indicate that embryogenic cultures of Scots pine are proliferating by a cleavage-like process.
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| 50. |
- Merino, Irene, et al.
(författare)
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Transcript profiling for early stages during embryo development in Scots pine
- 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: Characterization of the expression and function of genes regulating embryo development in conifers is interesting from an evolutionary point of view. However, our knowledge about the regulation of embryo development in conifers is limited. During early embryo development in Pinus species the proembyo goes through a cleavage process, named cleavage polyembryony, giving rise to four embryos. One of these embryos develops to a dominant embryo, which will develop further into a mature, cotyledonary embryo, while the other embryos, the subordinate embryos, are degraded. The main goal of this study has been to identify processes that might be important for regulating the cleavage process and for the development of a dominant embryo.Results: RNA samples from embryos and megagametophytes at four early developmental stages during seed development in Pinus sylvestris were subjected to high-throughput sequencing. A total of 6.6 million raw reads was generated, resulting in 121,938 transcripts, out of which 36.106 contained ORFs. 18,638 transcripts were differentially expressed (DETs) in embryos and megagametophytes. GO enrichment analysis of transcripts up-regulated in embryos showed enrichment for different cellular processes, while those up-regulated in megagametophytes were enriched for accumulation of storage material and responses to stress. The highest number of DETs was detected during the initiation of the cleavage process. Transcripts related to embryogenic competence, cell wall modifications, cell division pattern, axis specification and response to hormones and stress were highly abundant and differentially expressed during early embryo development. The abundance of representative DETs was confirmed by qRT-PCR analyses.Conclusion: Based on the processes identified in the GO enrichment analyses and the expression of the selected transcripts we suggest that (i) processes related to embryogenic competence and cell wall loosening are involved in activating the cleavage process; (ii) apical-basal polarization is strictly regulated in dominant embryos but not in the subordinate embryos; (iii) the transition from the morphogenic phase to the maturation phase is not completed in subordinate embryos. This is the first genome-wide transcript expression profiling of the earliest stages during embryo development in a Pinus species. Our results can serve as a framework for future studies to reveal the functions of identified genes.
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