Poster: Photosynthesis

Abs # 335: The relationship between the expression of rbcS and rbcL genes in tobacco plant

Presenter:	Ichikawa, Katsuhiko , k-ichika@bs.aist-nara.ac.jp
Authors	Ichikawa, Katsuhiko  (A)   Kato, Ko  (A)   Sekine, Masami  (A)   Shinmyo, Atsuhiko  (A)
Affiliations:	(A): Nara institute of science and technology

Ribulose 1,5-bisphosphate carboxylase/oxigenase (RuBisCO) is the key enzyme of photosynthetic carbon assimilation. RuBisCO is composed of eight small subunits (SSU) and eight large subunits (LSU). The LSU is encoded by rbcL gene within chloroplast genome and synthesized in the chloroplast. The SSU is encoded by a family of rbcS genes within the nuclear genome, synthesized in the cytoplasm as a precursor with a transit peptide, and then transported into the chloroplast. To understand the relationship between the expression of rbcS and rbcL genes at different developmental stage in leaves, we generated transgenic tobacco plants harboring antisense rbcS under the control of dexamethasone@(DEX) -inducible promoter. In these plants, the amount of endogenous rbcS mRNA can be artificially reduced by induction of antisense rbcS mRNA using DEX treatment.@These transgenic plants were cultured in a hydroponic growth medium with or without DEX. We investigated the effect of rbcS mRNA reduction on the expression of rbcL gene and the accumulation of RuBisCO in young and mature leaves.