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Browsing by Subject "tissue culture"

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  • Liu, Yanbo (2011)
    Calendula officinalis is grown widely as an ornamental plant across Europe. It belongs to the large. Asteraceae family. In this study, the aim was to explore the possibilities to use Calendula officinalis as a new model organism for flower development and secondary mechanism studies in Asteraceae. Tissue culture of Calendula officinalis was established using nine different cultivars. Murashige & Skoog (MS) medium with four different combinations of plant growth regulators were tested. Of all these combinations, the medium containing 1mg/l BAP, 0.1 mg/l IAA, and 1mg/l Zeatin achieved highest frequency of adventitious shoot regeneration from hypocotyl and cotyledon explants. Virus-induced gene silencing is a recent developed genetic tool for charactering the gene functions in plants, and extends the range of host plants that are not accessible for Agrobacterium transformation. Here, tobacco rattle virus (TRV)-based VIGS technique was tested in calendula (cv. Single Orange). We used TRV carrying Gerbera hybrid phytoene desaturase (PDS) gene fragment to induce PDS silencing in calendula. Vacuum infiltration and syringe infiltration methods both resulted in photo-bleaching phenotypes in leaves, bracts and petals. Loss-of-function phenotypes occurred on calendula 13 days post-infiltration. In conclusion, the data indicates that calendula explants can be regenerated through tissue culture which is a prerequisite for development of stable transformation methods. However, further optimization is still needed to improve the frequency. In addition, VIGS was applied to silence PDS marker gene expression indicating that this method has potential for gene functional studies in future.
  • Hautsalo, Juho (2013)
    The objective of this study was to develop functional method for producing doupled-haploid plants for faba bean. Microspore culture is an advanced method to produce doubled-haploids and it is based on the totipotent nature of plant cells, since even a microspore, which is an immature pollen cell with haploid genome, can develop into a plant. This plant is either haploid or doupled haploid depending on whether there has been chromosome doubling or not and because the chromosomes either do not have pairs or the pairs are pure copies of each other, the plant is completely homozygous. Doubled haploids are already used in breeding programs with several crops such as wheat, barley and oilseed rape. Faba bean is an important legume for food, feed and crop rotation. Together with other legumes it has the potential to replace soybean imports entirely in Finland. Faba bean yield stability and anti-nutritional factors restrain its use and active breeding is required to improve the crop. In Finland, where pea and faba bean are the only grain legumes actively cultivated, the breeding of faba bean has been recently reactivated and its objectives are earliness, higher yield, protein content and improved quality factors. Big bottle neck in faba bean breeding is the creation of pure homozygote lines because the partial cross-breeding in the species sets restrains for the procedure. In this study promising pea and chick pea protocols that were developed in 2009 and an efficient rapeseed protocol were applied with faba bean. The interaction of various stress treatments and two different induction media with five genotypes of faba bean on microspore culture were analysed. Pro-embryos and cell divisions were observed from the cultures. Heat shock was the most effective stress treatment. Effects of density and induction medium were high and cultivar’s low tannin content seemed to impact positively to induction efficiency. These results suggest that for faba bean microspore culture is as suitable method as anther culture is and that there is hope to produce doubled-haploid faba beans in the future.
  • Kaarela, Tiina (2022)
    Kainate type glutamatergic receptors (KARs) modulate synaptic transmission and neuronal excitability depending on their subunit composition and localization. Developmental expression of KARs in the immature hippocampus is suggested to promote activity dependent synchronization of neuronal networks, yet the exact mechanisms are still unclear. Here we asked how local manipulation of KAR subunit GluK1 at CA3 pyramidal cells modulates synchronous network activity in postnatal hippocampus in vitro. We hypothesized that local KAR enhancement will promote functional connectivity and synchronous activity in the networks. Multichannel recordings were used to study spatio-temporal profile of network activity in organotypic hippocampal slice cultures. We show, that local GluK1 enhancement is affecting spontaneous activity patterns and that the population discharges recruit the whole network more efficiently compared to control. In addition, the activities at the site of GluK1 overexpression are more correlated to CA1 and DG regions. Our data suggests that facilitated spatial propagation of population discharges promote synchronization of network activity in KAR expressing slices. These findings support and supplement the previous hypothesis that KARs might play essential role in the functional integration of neurons in hippocampal circuitries.