| 11. |
- Leonova, Svetlana
(författare)
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Lipids in seeds of oat (Avena spp.), a potential oil crop : content, quality, metabolism, and possibilities for improvement
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New oil crops with high yield and oil content are urgently needed. Oat is the only cereal that accumulates substantial amount of lipids in the endosperm. This gives it potential as an oil crop, which could address both nutritional and environmental concerns of modern society. To develop oat with increased oil content, thorough investigations on its lipid metabolism and tools for genetic manipulations are needed. Analyses of lipids in seeds of wild and cultivated oat species revealed variation in wild oat accessions in both oil content and quality. This variation should allow for development of new oat varieties for diverse applications. However, to develop oat as an oil crop, a level of 20% of the seed dry weight as oil is required and the range of oil content in the studied accessions was 4-10%. Another feature which showed almost no deviation was the amount of omega 3 fatty acid, -linolenic acid (0.6-2.1%). To develop oat varieties with ultra-high seed oil and increased content of omega 3 fatty acids, a biotechnological approach is preferred to conventional breeding methods. Lipids in oat endosperm have been reported to exist, not enclosed in oil bodies, but as non-structured oil smear. In my study, I also observed oil smears, a phenomenon probably correlated with the reduced amount of oil body associated proteins in the endosperm, as revealed by microscopic and staining methods. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil body protein. Biochemical studies on lipid mobilization during oat seed germination demonstrated efficient utilization of oil reserves from the starchy endosperm; these results were corroborated by microscopy. An oat cultivar which is capable of accumulating high amounts of oil in the endosperm was shown to be also efficient in utilizing these reserves upon germination. Agrobacterium-mediated transformation is one of the methods for modification of oat oil content and/or its quality. The results of the analyses aimed at development of an Agrobacterium-mediated oat transformation protocol are presented in this thesis.
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| 12. |
- Ortiz Rios, Rodomiro Octavio
(författare)
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New quantitative trait loci for enhancing adaptation to salinity in rice from Hasawi, a Saudi landrace into three African cultivars at the reproductive stage
- 2014
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Ingår i: Euphytica. - : Springer Science and Business Media LLC. - 0014-2336 .- 1573-5060. ; 200, s. 45-60
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Tidskriftsartikel (refereegranskat)abstract
- Salinity is a major constraint affecting rice productivity in rainfed and irrigated agro-ecosystems. Understanding salinity effects on rice production at the reproductive stage could improve adaptation for this trait. Identifying quantitative trait loci (QTLs) controlling adaptation to salinity may also accelerate breeding rice germplasm for environments prone to this stress. We used the salt tolerant landrace 'Hasawi' as a donor parent to generate three F-2 offspring (consisting each of 500 individuals) with three African cultivars ('NERICA-L-19', 'Sahel 108' and 'BG902') used as recipient parents (RP). The F(2)s and F(2:3)s were evaluated for grain yield and other traits in saline fields. Salinity caused reduction in all measured traits across the F-2-derived offspring, e. g. grain yield reduced between 65 and 73 %, but some offspring had twice the RP's grain yield. QTL analysis revealed 75 QTLs for different traits in all 3 genetic backgrounds (GBs): 24 of them were common among all the 3 GBs while 31 were noted in 2 GBs, and 17 in one GB. 'Hasawi' contributed on average 49 % alleles to these QTLs. Two yield and yield related QTLs (qGY11 and qTN11) common in all 3 GBs were mapped on the same chromosomal segment suggesting these QTLs might be stable across different GBs. Four other QTLs were strongly associated with salinity tolerance with peak marker RM419, representing a potential candidate for MAS due to high LOD score and relatively large effect QTLs.
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| 13. |
- Ortiz Rios, Rodomiro Octavio
(författare)
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Peanut improvement for human health
- 2014
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Ingår i: Plant Breeding Reviews: Volume 38. - Hoboken, New Jersey : John Wiley & Sons, Inc.. - 9781118916834 ; 38, s. 143-185
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Bokkapitel (refereegranskat)abstract
- Peanut (Arachis hypogaea L., Fabaceae) is an energy-dense and nutritious food. Regular consumption of peanuts improves human health. Oil content and oil quality, which is determined by variation in oleic (O) and linoleic (L) fatty acids, are important seed quality traits in peanut. Aflatoxin (produced by fungus Aspergillus flavus and Aspergillus parasiticus) is a serious health problem, whereas peanut allergy is a potentially life-threatening and often lifelong food allergy. High O/L ratio increases shelf life of peanut products and, therefore, their marketability. Germplasm and advanced breeding lines with oil content as high as 55–60% and O/L ratio ranging from 7:1 to 40:1 are available for use in peanut breeding. Global warming has a significant impact on the nutritional quality of food crops. Identification of germplasm with stable seed quality traits will be a prerequisite to initiate quality breeding in peanut. Peanut cultivars with high oleate content, developed by conventional breeding and selection, are widely grown in the United States. Marker-aided backcross breeding has led to the development of ‘Tifguard High O/L’ peanut cultivar in the United States. Enough genetic variation in seed iron and zinc content has been noted, but targeted breeding for these micronutrients in peanut is yet to begin. Peanut is devoid of β-carotene—a precursor of vitamin A. Using a cotyledon-based Agrobacterium-mediated genetic transformation system and the maize psyI gene driven by the At oleosin promoter, β-carotene-rich transgenic peanuts have been achieved. Transgenic peanuts with the antifungal gene cpo-p inhibited A. flavus hyphal growth or those containing the Rchit gene have shown a broader spectrum of resistance against fungal infection including A. flavus. Knocking out genes for the allergenic proteins, using targeting-induced local lesions in genomes (TILLING) or RNAi approaches, has shown promise to derive mutants or transgenic events lacking allergenic seed proteins, with no adverse effect on seed quality or viability. These genetic stocks when available to researchers may lead to breeding agronomically superior nutritionally enhanced peanut cultivars, which will be free from allergens and toxins.
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| 14. |
- 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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| 15. |
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| 16. |
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| 18. |
- Ortiz Rios, Rodomiro Octavio
(författare)
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Advances in Transgenic Vegetable and Fruit Breeding
- 2014
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Ingår i: Agricultural Sciences. - : Scientific Research Publishing, Inc.. - 2156-8553 .- 2156-8561. ; 5, s. 1448-1467
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Tidskriftsartikel (refereegranskat)abstract
- Vegetables and fruits are grown worldwide and play an important role in human diets because they provide vitamins, minerals, dietary fiber, and phytochemicals. Vegetables and fruits are also associated with improvement of gastrointestinal health, good vision, and reduced risk of heart disease, stroke, chronic diseases such as diabetes, and some forms of cancer. Vegetable and fruit production suffers from many biotic stresses caused by pathogens, pests, and weeds and requires high amounts of plant protection products per hectare. United States vegetables farmers are benefiting from growing transgenic squash cultivars resistant to Zucchini yellow mosaic virus , Watermelon mosaic virus , and Cucumber mosaic virus , which were deregulated and commercialized since 1996. Bt- sweet corn has also proven effective for control of some lepidopteran species and continues to be accepted in the fresh market in the USA, and Bt- fresh-market sweet corn hybrids are released almost every year. Likewise, transgenic Bt- eggplant bred to reduce pesticide use is now grown by farmers in Bangladesh. Transgenic papaya cultivars carrying the coat-protein gene provide effective protection against Papaya ring spot virus elsewhere. The transgenic “Honey Sweet” plum cultivar provides an interesting germplasm source for Plum pox virus control. Enhanced host plant resistance to Xanthomonas campestris pv. musacearum , which causes the devastating banana Xanthomonas wilt in the Great Lakes Region of Africa, was achieved by plant genetic engineering. There are other vegetable and fruit crops in the pipeline that have been genetically modified to enhance their host plant resistance to insects and plant pathogens, to show herbicide tolerance, and to improve features such as slow ripening that extends the shelf-life of the produce. Consumers could benefit further from eating more nutritious transgenic vegetables and fruits. Transgenic plant breeding therefore provides genetically enhanced seed embedded technology that contributes to integrated pest management in horticulture by reducing pesticide sprays as well as improving food safety by minimizing pesticide residues. Furthermore, herbicide-tolerant transgenic crops can help reducing plough in fields, thereby saving fuel because of less tractor use, which also protects the structure of the soil by reducing its erosion. Transgenic vegetable and fruit crops could make important contributions to sustainable vegetable production and for more nutritious and healthy food. Countries vary, however, in their market standards of acceptance of transgenic crops. Biotechnology products will be successful if clear advantages and safety are demonstrated to both growers and consumers
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| 19. |
- Pham, Toan Duc
(författare)
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Analyses of genetic diversity and desirable traits in sesame (Sesamum indicum L., Pedaliaceae) : implication for breeding and conservation
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sesame (Sesamum indicum L., Pedaliaceae) is a traditional oil crop cultivated in Vietnam and Cambodia. It is known as the king of oil seeds in Vietnam due to the high oil content (50-60%) in its seed. Yet, the insufficient genetic information regarding Vietnamese and Cambodian sesame populations is limiting the access to useful traits present among adapted landraces in this region. The purpose of this study was to characterize various sesame accessions to gain information that could help design strategies for future breeding program and conservation of this crop in the two countries. Morphological and molecular markers as well as oil content and quality analyses were employed to evaluate sesame accessions from different sources. High genetic variation was found among populations of sesame collected in Vietnam and Cambodia. The two type of markers, morphological and molecular, were both useful in analyzing the extent of genetic diversity in sesame and the result of these analyses will help to better understand the genetic diversity and relationship within and among populations. Overall, the sesame accessions included in the study showed a correlation with their geographical origins such that accessions from the same region tended to have higher genetic similarity as compared to those from different regions. However, when cluster analysis was applied to evaluate the genetic relationship, some sesame accessions were found not to be grouped based on geographical origins. This contrasting result could perhaps be a result from the exchange over time, of sesame germplasm, between farmers across the regions. The results from morphological and oil content analyses showed that several sesame accessions in Southern Vietnam and Cambodia displayed a good potential for high seed yield and oil content. Overall, the studies in this thesis provide important insights into the populations of sesame in Vietnam and Cambodia and constitute a set of useful background information that can be used as a basis for future breeding strategy and improvement of sesame in this region.
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| 20. |
- Chawade, Aakash, et al.
(författare)
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Global expression profiling of low temperature induced genes in the chilling tolerant japonica rice jumli marshi
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:12, s. e81729-
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Tidskriftsartikel (refereegranskat)abstract
- Low temperature is a key factor that limits growth and productivity of many important agronomical crops worldwide. Rice (Oryza sativa L.) is negatively affected already at temperatures below +10°C and is therefore denoted as chilling sensitive. However, chilling tolerant rice cultivars exist and can be commercially cultivated at altitudes up to 3,050 meters with temperatures reaching as low as +4°C. In this work, the global transcriptional response to cold stress (+4°C) was studied in the Nepalese highland variety Jumli Marshi (spp. japonica) and 4,636 genes were identified as significantly differentially expressed within 24 hours of cold stress. Comparison with previously published microarray data from one chilling tolerant and two sensitive rice cultivars identified 182 genes differentially expressed (DE) upon cold stress in all four rice cultivars and 511 genes DE only in the chilling tolerant rice. Promoter analysis of the 182 genes suggests a complex cross-talk between ABRE and CBF regulons. Promoter analysis of the 511 genes identified over-represented ABRE motifs but not DRE motifs, suggesting a role for ABA signaling in cold tolerance. Moreover, 2,101 genes were DE in Jumli Marshi alone. By chromosomal localization analysis, 473 of these cold responsive genes were located within 13 different QTLs previously identified as cold associated.
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