Research Advances on Transposable Elements in Rice

Transposable elements are important components of plant genome and play critical roles in genome evolution. With the availability of complete rice genomic sequences, great progress has been made in identifying and characterizing rice transposons. To date, almost all types of transposons have been identified in rice, and they make up about 35% of the genome. Most transposons are silent during normal development, but they can be activated by factors such as tissue culture or radiation. The activation of transposons may induce the loss of gene function or affect rice gene expression. Six active transposons have been discovered, with Tos17 the first active transposon widely used in rice functional genomics studies. Transposons can also serve as a new type of molecular marker with use of the technique transposon display (TD), a useful tool in rice genetic mapping and the studies of genetic diversity.