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Browsing by Subject "Rubus"

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  • Analysis of raspberry ketone and related compounds from plant cell suspension cultures 
    Selin, Markus (2012)
    This thesis is constructed as a part of a larger research project aiming to increase understanding of polyketone reductases (PKR) and develop applications from them. PKRs are enzymes in biosynthetic pathways leading to several aromatic secondary metabolites in plants. The previous work in the research group has led to establishment of several callus cultures from plants belonging to the genus Rubus in the family Rosaceae. The aim in the experimental part of this thesis is the identification and semi-quantitation of raspberry ketone (RK) and related aromatics in the cell suspension cultures initiated from the previously established callus cultures. RK is biosynthetically produced by reduction of p-hydroxybenzalacetone (p-OH-BA) by benzalacetone reductase (BAR). As a part of the experimental work, p-OH-BA has to be chemically synthetized and analysed. Special emphasis is placed to experiment, develop and validate an extraction method for phenolic compounds using ASE 200 working station. In the review part of this thesis, the basic procedures of chemical analysis are described, optimization and validation of analytical methods are discussed, and lastly studies related to raspberry ketone (RK) are summarized. The detection limit is 0.73 µg/ml for RK with the established UPLC-UV method, and the quantitation limit (QL) is 2.22 µg/ml. At the QL, the standard deviation of the extraction method is 8.9 % and the results are 6.4 % higher than expected. At the high end of the standard curve the extraction results are 18.7 % higher than expected. Some changes are proposed to optimize the method. Analysis of the cell line extracts with the established UPLC-UV method did not readily reveal any of the studied compounds. Although the interpretation of the results of the MS experiment is still underway, RK was detected from the arctic bramble cell line Ra15. Also, a possible derivative of zingerone was detected from cloudberry cell line extract even without the corresponding standard compound. This shows the power of the MS in metabolite profiling, and gives a course for future studies.
  • Phyllosphere microbiota of three Rubus species - community composition, transmission between plants, and effect on plant growth 
    Leino, Sara (2023)
    The above-ground surfaces of plants (the phyllosphere) are inhabited by a diverse variety of microbes that interact with the host plant affecting its health and growth. One of the predominant factors influencing the composition and formation of the phyllosphere microbial community is the species and genotype of the plant. In my thesis, I investigated whether three different Rubus species (R. arcticus, R. saxatilis, and R. chamaemorus) form similar phyllosphere microbial communities, and whether the genotype of the host plant has more impact on the community composition than the microbiota that the plants are exposed to. I also tested how different microbiota treatments would affect Rubus plant growth. The experiment was conducted with micropropagated plants of the three aforementioned Rubus species. The plants were treated with different microbiota collected from the leaves of wild plants of the three Rubus species and the growth of the plants was observed. The phyllosphere fungal and bacterial communities of the plants were sequenced from leaf samples and analyzed to inspect the overall diversity and difference of the communities (using Kruskal-Wallis test and PERMANOVA) and to identify possible core microbes within the Rubus species’ phyllosphere communities. I found that Rubus phyllosphere microbiota was dominated by bacteria classes Alphaproteobacteria and Gammaproteobacteria, and fungal classes Eurotiomycetes, Sordariomycetes, Agaricomycetes, and Dothideomycetes. The host plant genotype had more significance on the composition of phyllosphere microbiota than the origin of the microbiota. The different microbiota treatments had no significant effect on the plant leaf growth. My thesis shows how host plant genotype influences the shaping of the phyllosphere communities as well as how transferable the microbial communities are between species from the same genus. Understanding of the phyllosphere microbiota can have potential applications in the promotion of plant health and fitness.

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