1.
Zubair, Muhammad
(författare)
Genetic variation, biochemical contents and wound healing activity of Plantago major
2012
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Plantago major L. (greater plantain, common plantain) has been used as a wound healing remedy in different parts of the world for centuries. Different bioactive compounds have been proposed to contribute to the wound healing properties of this plant. The present study was undertaken to investigate the impact of some genetic and environmental factors on the wound healing activity of common plantain. Seeds of P. major were collected from five populations in different parts of Sweden, and were germinated and grown in a greenhouse. As expected for an inbreeding species, RAPD analyses demonstrated considerable between-population variation but very sparse within-population and within-subpopulation variation. Six major phenolic compounds were encountered in samples of P. major, four of which were identified for the first time in this thesis; PLMA 1–PLMA 4. Between-population and sub-population differences in the contents of these chemical compounds showed no correlation with RAPD-based estimates of genetic relatedness. The contents of these compounds differed greatly between different plant organs of P. major. The highest concentration of plantamajoside and PLMA 2 was found in leaves whereas the highest concentration of verbascoside was found in flower stalks and seeds. Contents were significantly higher in freeze-dried leaf samples compared to samples dried at higher temperatures. Both water and ethanol-based extracts of P. major leaves stimulated the cell proliferation and migration in an in vitro scratch assay, and also showed anti-inflammatory activity in an in vitro NF-kB assay with oral epithelial cell cultures. Similarly, these extracts stimulated wound healing activities in ex vivo tests using detached pig ears. Further breeding efforts aimed at developing P. major as a crop plant, and medicinal research aimed at elucidating and optimizing extracts with wound healing properties, are thus warranted.
2.
Roos, Jonas
(författare)
Verticillium longisporum and plant immunity responses in Arabidopsis
2014
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Verticillium spp. are soil-borne ascomycete fungi belonging to a subgroup of Sordariomycetes, and the three major plant pathogens Verticillium longisporum, V. dahliae and V. albo-atrum cause disease on numerous plant species worldwide. In Sweden, V. longisporum poses a threat to Brassica oilseed crops, and is thus emphasized in this thesis. Here the early immune responses to V. longisporum in the model plant Arabidopsis and recent data on the V. longisporum genome are presented. Three genes of importance in the Arabidopsis–V. longisporum interaction were studied. The genes were identified via transcriptome and single nucleotide polymorphism (SNP) analysis. RabGAP22, a RabGTPase-regulating protein, was found to contribute to V. longisporum resistance. Pull-down assays revealed SERINE:GLYOXYLATE AMINOTRANSFERASE (AGT1) as an interacting partner during V. longisporum infection and the two proteins were shown to co-localize in the peroxisomes. Unexpectedly, a role for RabGAP22 was also found in stomatal immunity. The monoterpene synthase TPS23/27 was on the other hand found to contribute to fungal invasion, by triggering germination of V. longisporum conidia. The third gene codes for a nitrate/peptide transporter, NPF5.12. Pull-down experiments and fluorescent imaging revealed interaction between NPF5.12 and a major latex protein family member, NPFBP1. Implications in plant immunity processes of these three genes are further discussed. The genomes of two Swedish V. longisporum isolates were sequenced and found to have a size of approximately 70 Mb and harbor ~21,000 protein-coding genes. Initial analyses revealed that 86% of the V. longisporum genomes are shared with V. dahliae and V. albo-atrum, with a high extent of gene duplications. Large numbers of proteins were predicted to contain secretion motifs, and this group of proteins is presumed to play major roles in the interactions with V. longisporum host plants. In conclusion, this thesis work has revealed new fungal and plant host genes and thereby laid the basis for new plant breeding and disease protection strategies.
3.
Ghasemkhani, Marjan
(författare)
Genetic basis for resistance against fruit tree canker in apple
2012
Rapport (övrigt vetenskapligt/konstnärligt) abstract
Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker which is regarded as a serious economic problem in horticulture. This fungus causes notable damage to apple trees and it is very important in some regions, especially North western Europe, where it can result in death of spur shoots and branches. Although it occurs in a wide range of temperatures, it is associated with wet weather and climate has an important effect on the geographic distribution. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Also, spores produced on the infected wood can act as an infection source in the orchards. The fungus can therefore be introduced into new orchards with infected planting material from other orchards or tree nurseries. Chemical and mechanical control like spraying of fungicides, covering wounds with paint, and cutting out infected branches, do not prevent the occurrence of epidemics. Breeding cultivars with a high level of resistance towards canker would be of great help towards the avoidance of this disease. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported and no major genes have been identified. Therefore, apple genotypes with comparatively high levels of genetically determined partial resistance should be identified for use in apple breeding.
4.
Lehrman, Anna, et al.
(författare)
Framtidens mat - om husdjursavel och växtförädling
2014
Bok (övrigt vetenskapligt/konstnärligt) abstract
Du har kanske inte funderat över varför tomater ser ut som de gör, varför våra husdjur är så lugna och vänliga, eller hur det är möjligt att köpa en vattenmelon utan kärnor. Trots att växtförädling och djuravel har format det mesta vi äter, är det få människor som är medvetna om vilka vetenskapliga upptäckter och vilket omfattande arbete som ligger bakom maten vi lägger på våra tallrikar. Med den här boken vill vi ge en översikt över domesticeringens och förädlingens bakgrund, från jordbrukets början för mer än 10 000 år sedan till dagens molekylära arbete. Vi beskriver grunderna för genernas strukturer och funktioner, varför och hur olika avels- och förädlingsmetoder används och ger en inblick i lagstiftningen kring användning av genteknik i Sverige och EU. Vi ger också en överblick över olika produkter som tagits fram genom genetisk modifiering (GM) och en sammanfattning av de ekonomiska konsekvenserna av GM-grödor. Vidare diskuterar vi etiska frågor som rör avel och förädling i allmänhet och genetisk modifiering i synnerhet.
5.
Leonova, Svetlana
(författare)
Lipids in seeds of oat (Avena spp.), a potential oil crop : content, quality, metabolism, and possibilities for improvement
2013
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.
6.
Ortiz Rios, Rodomiro Octavio
(författare)
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
Ingår i: Euphytica. - : Springer Science and Business Media LLC. - 0014-2336 .- 1573-5060. ; 200, s. 45-60
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.
7.
Ortiz Rios, Rodomiro Octavio
(författare)
Peanut improvement for human health
2014
Ingår i: Plant Breeding Reviews: Volume 38. - Hoboken, New Jersey : John Wiley & Sons, Inc.. - 9781118916834 ; 38, s. 143-185
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.
8.
9.
Turesson, Helle, et al.
(författare)
Starch biosynthetic genes and enzymes are expressed and active in the absence of starch accumulation in sugar beet tap-root
2014
Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 14
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.
10.
