Poster: Membrane Transport

Abs # 1232: Sink-specific expression of cell wall invertase in Arabidopsis thaliana and Nicotiana tabacum

Presenter:	Schweinichen, von, Constantin , cvschwei@biologie.uni-erlangen.de
Authors	Schweinichen, von, Constantin  (A)   Büttner, Michael  (A)
Affiliations:	(A): University of Erlangen, Dept. of Molecular Plant Physiology

Metabolically active sink-tissues seem to have an increased demand for hexoses. Therefore, the cooperation of apoplastic invertases (cwINVs) and monosaccharide transporters (STPs) in the plasma membrane has been postulated for sink-loading during certain phases of development. We are investigating the sink/source-relation by modulating the metabolites and their transport systems. To this end, we are generating plants co-expressing a cell wall invertase and a monosaccharide transporter under the control of sink-specific promoters, which could results in a more effective and/or elongated uptake of hexoses into sinks. Therefore, the root-specific Pyk10-promoter from Arabidopsis and the seed-specific SUT1-promoter from Vicia faba has been used. First, we reconfirmed the seed-specificity of the SUT1-promoter in Arabidopsis by promoter-reporter plants. Transgenic plants expressing cwINV under the control of these sink-specific promoters are analyzed for transgene expression (RT-PCR), altered invertase activity and changes in assimilate partitioning (sinks/ whole plant). We analyzed Arabidopsis plants expressing the cell wall invertase driven by the Pyk10-promoter in roots, which leads to an increase in biomass compared to wildtype. In Nicotiana tabacum, the embryo-specific expression of the cell wall invertase leads to an increased weight of the transgenic seeds.