Abstract
Protochlorophyllide (Pchlide) reduction is the penultimate step of chlorophyll (Chl) biosynthesis, which is catalyzed by two structurally unrelated enzymes; dark-operative Pchlide oxidoreductase (DPOR) and light-dependent Pchlide oxidoreductase (LPOR). Since LPOR is the sole Pchlide reductase in angiosperm, dark-grown seedlings become etiolated. The ternary complex Pchlide-NADPH-LPOR is highly accumulated in the etioplasts to form prolamellar body (PLB) characterized by a unique paracrystalline structure. Most oxygenic phototrophs except angiosperms produce Chl even in the dark and PLB is not formed as they have DPOR together with LPOR. In these organisms the expression level of LPOR is kept low in contrast to the high level of accumulation of angiosperm etioplasts. Here we show the impact of the overexpression of LPOR in the cyanobacterium Leptolyngbya boryana. We will present the results of phenotypic analysis including electron micrographic observation of a transformant overexpressing LPOR.
