Abstract:Retrotransposons are a class of eukaryotic transposable elements, consisting of the long terminal repeat (LTR) and non-LTR retrotransposons. Retrotransposons are ubiquitous in the plant kingdom by high copy number and can be transmitted between generations by vertical transmission and between species by horizontal transmission. The same family retrotransposons presented highly heterogeneous populations in all higher plant genomes. Many of the plant retrotransposons are transcriptionally activated by various biotic and abiotic stress factors. Retrotransposons are used as molecular markers for their traits. S-SAP, IRAP, REMAP and RBIP are developed and will be applied widely in gene mapping, genetic biodiversity and phylogeny studies, and cultivar certification.