Abstract
Chlorophyllide a oxygenase (CAO) catalyzes the conversion of chlorophyll a to chlorophyll b. The amount of chlorophyll b is regulated by the protein level of CAO. The CAO protein consists of three domains, namely A, B, and C domains. Among these domains, only the A domain is necessary for the regulation of the CAO protein level. Previously, we found that chlorophyll b triggers the degradation of CAO. In order to understand the regulatory mechanism of CAO, we mutagenized a transgenic plant of Arabidopsis thaliana that overexpressed the fusion protein of GFP and the A domain. We isolated 73 mutants that were impaired in the regulatory mechanism of CAO by the observation with laser-scanning confocal microscope. We classified these mutants into 11 groups according to the accumulation patterns of the GFP-CAO fusion protein. We will report the phenotypes of the mutants and will discuss the possible regulatory mechanism of CAO.
