ANTI-SENSE RNA FOR CAB TRANSCRIPT TO REDUCE CHLOROPHYLL CONTENT IN PLANTS

摘要

The initial steps in photosynthesis are the conversion of light energy into chemical energy. This conversion is performed by the multisubunit proteinpigment complexes of the thylakoid membranes. Oxygen-evolving photosystems contain photosystem I (PSI) and photosystem II (PSII), which act in tandem. In PSII, the majority of light-adsorbing chlorophylls are attached to LHCII, the light harvesting complex associated with this photosystem. LHCII is the most abundant member of the family of chlorophyll a/b binding (CAB) proteins. A gene encoding a type I chlorophyll a/b binding protein of LHCII (ICABPSII) has been cloned from Brassica napus L. An anti-sense RNA of this gene has been used to reduce the amount of chlorophyll a/b binding protein and thus reduce theamount of chlorophyll in the resulting transgenic plants. By using site specificpromoters the reduction of chlorophyll can be targeted to specific organelles inthe transgenic plant and thus can be used to reduce the green colour at these sites. Thus it is possible to use the anti-sense RNA of a chlorophyll a/b binding protein as a means for degreening, for example fruits, seeds or floral parts in transgenic plants.