Abstract
Gene targeting by homologous recombination (HR) is a powerful tool for reverse genetics. We have developed an efficient and generally applicable gene targeting (GT) in rice based on a large-scale transformation with strong positive-negative selection followed by PCR screening. To investigate the function of DNA methylation in rice, we generated transgenic rice plants having OsDRM1a disrupted by GT and obtained six independent T0 lines containing the mutated OsDRM1a gene in the heterozygous condition. Homozygous T1 plants showed characteristic phenotypes including dwarfism, reduced tillers, late heading, abnormal flowers, and activation of certain retrotransposons, indicating that OsDRM1a plays important roles in rice normal development and requires for the transcriptional suppression for some retrotransposons in the genome.
