Several Strategies for Dissecting and Controlling Functions in Plant Cells

Abstract

The strengths of gene promoters functional in chloroplasts have been evaluated for transient expression by particle bombardment to facilitate engineering of the chloroplast genome of Arabidopsis thaliana. The T7 RNA polymerase-recognized promoter was the most active in transgenic A. thaliana with T7 RNA polymcrase destined for chloroplasts. As a vital reporter of gene expression, an improved gene for green fluorescent protein (GFP) was chemically synthesized and resulted in approx. 100 times higher fluorescence intensity in A. thaliana. To overcome the limitations of experimentally designing of engineered proteins, we employed in vitro random mutagenesis of genes and subsequent selection of their transformants under certain conditions. The strategy was successfully applied to the photosystem II reaction center D1 protein to confer phototolerance on it.