- [Show abstract] [Hide abstract] ABSTRACT: Vegetatively propagated crop plants, such as potato, are ideal material to develop effi cient commercial applications for cloning by in vitro techniques. To enable profi table production of plants true to type, extensive proliferation rates along with large-scale culture systems are needed. The traditional in vitro propagation techniques are however laborious and time consuming, and therefore the cloning process should be as automated as possible, keeping in mind the starting material, proliferation method, and further handling. Because cultivated potato (Solanum tuberosum L.) has the capacity to produce microtubers in vitro, it is an exploitable trait for application in the seed potato production industry. Microtubers have already been applied for mass production of planting materials in various types of semisolid media and in liquid cultures including different temporary immersion techniques, such as ebb-and-fl ow technique in glass fermentors, Rita® and twinfl ask systems, nutrient mist bioreactors, and also in plastic vessel cultivations, such as the Liquid Lab Rocker™ technique. Currently, the liquid cultures are considered superior compared to applications using semi-solid medium, because the liquid culture medium can be replaced simultaneously for a number of explants instead of transferring single plantlets one by one to a fresh medium. Furthermore, bioreactors can easily be applied on liquid culture systems for large-scale propagation of potato microtubers. Bioreactors enable further process automation, quality control systems and synchronous material development, which pave the way for effi cient, profi table production processes for cultivated potato. Bioreactors combined with techniques for inducing somatic embryogenesis may offer a promising tool for mass propagation systems in the future. Regardless of the high potential of somatic embryogenesis, only a few systems have so far been used for commercial propagation of plants with economical value. In the future, improved protocols and maintenance of embryogenic status in cultures could be achieved by combining information from gene expression studies with selection of highly embryogenic tissues and medium supplementations.
Dataset: jaakola supplementary data
- [Show abstract] [Hide abstract] ABSTRACT: Efficient commercial applications using in vitro techniques have facilitated the cloning of vegetatively propagated crop plants. Extensive proliferation rates along with large-scale culture systems for the rapid multiplication of plants are necessary to reduce the production costs in the future. Mechanisation and automatisation of the whole cloning process are necessary to overcome the laborious and time-consuming traditional in vitro propagation techniques, such as cloning through single-node cuttings or use of adventitious shoot formation. Capacity to produce microtubers is a trait having several benefits, which can be applied for tuber seed industry of cultivated potato (Solanum tuberosum L.). In microtuber formation of potato, various types of semisolid media in different cultivation vessels have been applied. In addition, liquid cultures including different temporary immersion tehniques, ebb-and flow technique in glass fermentors, Rita and Twin flask systems, nutrient mist bioreactor and plastic bag cultivations, such as Liquid Lab Rocker technique have been studied to enhance the production of microtubers. Liquid cultures offer several advantages in comparison to the cultivation using semi-solid media. The cultivations are generally time consuming since instead of individually transferred single explants, the replacement of the entire medium is an advantage of using liquid culture. The application of bioreactors along with advantages derived from liquid culture systems have made large scale propagation of potato microtubers more feasible. The induction of microtubers by bioreactors offers opportunities to process automation, quality control systems and synchronous material development resulting finally in reduction of production costs in potato multiplication.
- [Show abstract] [Hide abstract] ABSTRACT: Anthocyanins are important health-promoting phytochemicals that are abundant in many fleshy fruits. Bilberry (Vaccinium myrtillus) is one of the best sources of these compounds. Here, we report on the expression pattern and functional analysis of a SQUAMOSA-class MADS box transcription factor, VmTDR4, associated with anthocyanin biosynthesis in bilberry. Levels of VmTDR4 expression were spatially and temporally linked with color development and anthocyanin-related gene expression. Virus-induced gene silencing was used to suppress VmTDR4 expression in bilberry, resulting in substantial reduction in anthocyanin levels in fully ripe fruits. Chalcone synthase was used as a positive control in the virus-induced gene silencing experiments. Additionally, in sectors of fruit tissue in which the expression of the VmTDR4 gene was silenced, the expression of R2R3 MYB family transcription factors related to the biosynthesis of flavonoids was also altered. We conclude that VmTDR4 plays an important role in the accumulation of anthocyanins during normal ripening in bilberry, probably through direct or indirect control of transcription factors belonging to the R2R3 MYB family.
- [Show abstract] [Hide abstract] ABSTRACT: Potato (Solanum tuberosum L. ssp. tuberosum) microtubers were produced in vitro with Liquid Lab™ Rocker system. A thin-layer liquid culture was applied together with a regular pitch in autoclavable simple plastic vessels. All cultures were carried out at room temperature without contamination problems. Each cultivar tested (Asterix, Timo, Van Gogh, Velox) formed microtubers in the Liquid Lab system. The mean number of microtubers per vessel (50 explants) varied between 30 (cv. Asterix in 8weeks tuber induction) and 75 microtubers (cv. Velox in 11weeks tuber induction). Majority (63%) of the microtubers was sufficient by size and weight (above 200mg) for further storage at dormancy (4°C). The cv. Velox yielded the highest number of microtubers with cultivation capacity. As a result of prolonged microtuber induction of 2–3weeks, more microtubers with competence for cultivation were obtained per cultivar, except for cv. Van Gogh. Still, the mean weight of Van Gogh microtubers was significantly higher after prolonged microtuber induction (0.67g) than after short induction (0.51g). In conclusion, Liquid Lab™ Rocker system is a novel, efficient and rapid system for mass propagation of potato. KeywordsSeed potato-Bioreactor-Microtuber-Tissue culture
- [Show abstract] [Hide abstract] ABSTRACT: French tarragon (Artemisia dracunculus var. sativa) has been vegetatively propagated for centuries, but variability in the vegetative lines has not been studied. Three lines of French tarragon (A - C) were studied for their overwintering capacity at the limit of survival, their essential oil content and composition, and their genetic variability. Line B had the lowest Winter survival rate, the highest biomass yield, and the lowest content of essential oils. The essential oils of line B had higher proportions of cis- and trans-ocimenes, and contained less estragole and herniarin than the essential oils of lines A and C. When genetic diversity was studied using restriction fragment length polymorphism (RFLP), all French tarragon lines clustered together, while Russian tarragon was monophyletic Lines A and B were genetically closer to each other than line C. These results indicate that all three lines tested were genetically and biochemically different, which may have resulted from spontaneous mutations over centuries of vegetative propagation. Our results demonstrate the need to monitor and preserve the most important traits for future cultivation and use of vegetatively propagated herbs.