Abstract
Chlorophyllide a oxygenase (CAO) converts chlorophyll a to chlorophyll b.The CAO protein levels regulate accumulation of chlorophyll b. We previously demonstrated that the CAO levels were maintained at a low level in plants when a sufficient amount of chlorophyll b was accumulated.In order to reveal this feedback mechanism, we screened for mutants that accumulate a higher level of CAO protein in spite of the presence of chlorophyll b.
In order to monitor the CAO protein levels, we prepared Arabidopsis transgenic lines overexpressing GFP-CAO fusion proteins. The transgenic plant was mutated by EMS and screened with confocal microscopy. We isolated a line that showed a high GFP fluorescence. In the cotyledon of this line, the CAO protein level was higher than that in the parent line, whereas CAO protein was not detected in rossette leaves in both lines. Mapping of the mutation locus is in progress.
