Insertional mutagenesis in Arabidopsis : a tool for functional genomic analysis

The completion of the entire Arabidopsis genome sequence has been recently achieved. Approximately 30% of the predicted genes encode for proteins of unknown function, and only 9% of the genes have been characterized experimentally. Different genetic and molecular tools have been developed to address the functional significance of the genes discovered in EST and genome sequencing programs. Bioinformatic studies can assign putative functions by homology to known genes, while microarray technology can examine global and detailed gene expression patterns. Nevertheless, the identification and characterization of loss-of-function mutations remains a primary tool in functional genomics studies. Insertional mutagenesis approaches are well suited for large-scale functional analysis. Insertions of transposons or T-DNA in specific target genes can be easily detected by reverse genetic PCR-assisted screens. The molecular and phenotypic characterization of the insertional alleles provide vital data on the biological role of the disrupted genes