Identification of Photosynthesis-Related Genes in Rice Using FOX Hunting System

Photosynthesis is one of the most important determinants of crop productivity. Although many studies have been conducted to improve yield, very little progress has been made. In this study, we used rice FOX (Full length cDNA over-expressing) lines that rice full-length cDNAs were over-expressed in Arabidopsis to identify novel photosynthesis-related genes of rice. We have used imaging of chlorophyll fluorescence to screen candidates. To confirm over-expression of transformed cDNAs cause the observed phenotype, we generated transformants overexpressing each cDNA, resulting that eight lines showed the same phenotype as original lines. Isolated candidates could be classified into four categories depending on chlorophyll fluorescence parameters. We analyzed gene expression profile of three candidate lines showing similar photosynthetic characteristics using DNA microarray. We found commonly regulated genes among three candidates, indicating that candidates have both shared and independent influences on gene expression.