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Blueberry (Vaccinium corymbosum L.) is increasingly cultivated to produce high quality berries for consumption and potential applications in medicine, nutrition and as industrial precursors. Seasonal availability sets limitations on chemical compound isolation from cultivated plants. Biotechnological solutions, such as tissue cultures and metabolic engineering, can provide sufficient amounts of plant material with reasonably high metabolite levels, which may be adjusted by different strategies. Here, we describe our approach to modifying total phenolic content (TPC), antiradical activity (ARA) and amounts of selected organic acids in in vitro cultures of two varieties of V. corymbosum by varying the growth media. TPC, ARA and acid levels were determined in mature leaves of field-grown plants and in stable callus cultures derived from leaves of varieties ‘Bluecrop’ and ‘Duke’ grown on Murashige-Skoog (MS) and Woody plant (WP) media supplemented with varying concentrations and combinations of different plant growth hormones. TPC varied from 83 mg g -1 dry weight (DW) to 142 mg g -1 DW in leaves of ‘Bluecrop’ and ‘Duke’, respectively, and correlated with their ARA with ‘Duke’ at the lead. For callus cultures the highest ARA, as well as the highest TPC of 94 mg g -1 DW was observed in ‘Bluecrop’ grown on WP medium with 2,4-dichlorophenoxyacetic acid (2,4-D). High level of quinic acid was found in the mature leaves of all tested varieties, while callus cultures exhibited relative increase in amounts of malic, succinic and citric acids instead. Oxalic acid was found only in callus cultures.

Darba mērķis bija noskaidrot, vai endofītiskās mikrobiotas pārstādīšana, kā metodiska pieeja, var sniegt informatīvus rezultātus S.nigra mikrobiotas funkcionālās lomas raksturošanai. Tika pārbaudīta hipotēze, ka mikrobiotas pārstādīšana ietekmē melnā plūškoka audu ķīmisko sastāvu. In vitro pētījumā noteikta mikrobiotas transplantācijas ietekme uz plūškoka šūnu suspensiju kultūrām, kallusiem un in vitro dzinumu kultūrām, izvērtējot augšanas parametrus un kopējo flavonoīdu un fenolu satura. In situ pētījumos analizēta kopējās mikrobiotas pārstādīšanas ietekme uz savvaļas S.nigra ogu un ziedu dabisko endofītisko mikrobiotu un fitoķīmisko sastāvu. Novēroja mikrobiotas ietekmi uz melnā plūškoka audu fenolu un flavonoīdu saturu in vitro un in situ. Rezultāti parādīja, ka sekmīgai mikrobiotas pārstādīšanai in vitro ir vairāki būtiski ietekmējošie faktori: kopējās mikrobiotas inokulu koncentrācija, inokulēšanas stadija un ko-kultivēšanas ilgums. Izmantojot mikrobiotas pārstādīšanu in vitro šūnu suspensiju kultūrām izdevās paaugstināt flavonoīdu saturu. Mikrobiotas pārstādīšana in situ atstāja ietekmi uz dabiskās endofītiskās mikrobiotas taksonomisko struktūru un ietekmēja kopējo fenolu daudzumu plūškoka ogās. Kopumā rezultāti liecina, ka mikrobiotas transplantācija varētu tikt turpmāk sekmīgi izmantota, lai pierādītu un raksturotu endofītiskās mikrobiotas funkcionālo lomu ārstniecības augu ķīmiskā sastāva veidošanā., The thesis aims at exploring methodological aspects of the native endophytic microbiota transplantation in black elderberry Sambucus nigra and proposes its use as an experimental approach to characterize the functional role of microbiota. In vitro experiments assessed the effects of microbial transplantation on phytochemical content and growth parameters of elderberry cell suspension, callus, and in vitro shoot cultures. In situ experiments analyzed the effect of microbiota transplantation on the native endophytic microbial community and the phytochemical composition of the fruit and flowers of wild S. nigra. According to the results successful microbial transplantation in vitro requires optimization of microbial inoculum concentrations, inoculation stage, and co-cultivation duration. The effect of the microbiota on plant phenol and flavonoid content was observed in vitro and in situ. Microbial transplantation in vitro allowed for a significant increase of total flavonoid content of elderberry cell suspensions. Application of total microbiota inoculums in situ significantly affected native endophytic microbial communities and phytochemical content of wild elderberries. Collectively the results suggest that microbial transplantation is a valid approach for the functional characterization of endophytic microbiota of medicinal plants.