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Molecular characterization of several Brassica shoot apical meristem genes and the effect of their altered expression during in vitro morphogenesis

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dc.contributor.supervisor Stasolla, Claudio (Plant Science) en
dc.contributor.author Elhiti, Mohamed Abdelsamad
dc.date.accessioned 2010-08-16T15:46:14Z
dc.date.available 2010-08-16T15:46:14Z
dc.date.issued 2010-08-16T15:46:14Z
dc.identifier.citation Mohamed Elhiti et al. (2010). MODULATION OF EMBRYO-FORMING CAPACITY IN CULTURE THROUGH THE EXPRESSION OF BRASSICA GENES INVOLVED IN THE REGULATION OF THE SHOOT APICAL MERISTEM. Journal of Experimental Botany en
dc.identifier.uri http://hdl.handle.net/1993/4053
dc.description.abstract A common event during in vitro morphogenesis (either embryogenesis or shoot organogenesis) is the ability of somatic cells within the explants to de-differentiate and acquire “meristematic identity”. The developmental program of such meristematic cells can then be re-routed to form shoots or embryos depending on the imposed culture environment. The objective of this research is to investigate how the altered expression of Brassica genes regulating meristematic activity in vivo affects in vitro morphogenesis. It is predicted that ectopic expression of positive regulators of the shoot apical meristem, SHOOT MERISTEMLESS (STM) and ZWILLE (ZLL) which increase the pool of meristematic cells within the apical meristem, has a beneficial effect on somatic embryogenesis and shoot organogenesis. Conversely the over-expression of CLAVATA1 (CLV1), a negative regulator which depletes the pool of meristematic cells, should inhibit both processes. Over-expression of the Brassica STM in Arabidopsis enhanced the production of somatic embryos and shoots in vitro possibly by reducing the requirement of the tissue for exogenous auxin, which is the inductive signal for the production of embryogenic and organogenic cells. This was also accompanied by profound alterations in gene expression patterns affecting components of DNA methylation and glutathione metabolism, which are beneficial for embryo formation. The introduction of STM also enhanced Arabidopsis shoot organogenesis through profound transcriptional changes in cytokinin signalling. While the ectopic expression of the Brassica CLV1 inhibited both somatic embryogenesis and shoot organogenesis, the expression of ZLL had no effects on the production of somatic embryos but encouraged the formation of shoots. Taken together these results suggest the existence of similar genetic mechanisms regulating the formation of meristem cells in vivo and embryogenic/organogenic cells in vitro. en
dc.format.extent 5339912 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject SAM en
dc.subject Embryogenesis
dc.subject Shoot organogenesis
dc.subject SHOOT MERISTEMLESS
dc.subject CLAVATA1
dc.subject ZWILLE
dc.title Molecular characterization of several Brassica shoot apical meristem genes and the effect of their altered expression during in vitro morphogenesis en
dc.type info:eu-repo/semantics/doctoralThesis
dc.type doctoral thesis en_US
dc.degree.discipline Plant Science en
dc.contributor.examiningcommittee Tahir, Muhammad (Plant Science) Schroeder, Dana (Biological Sciences) Krochko, Joan (Plant Biotechnology Institute) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note October 2010 en


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