Specific suppression of long terminal repeat retrotransposon mobilization in plants.

The tissue culture passage necessary for generation of transgenic plants induces genome instability. This instability predominantly involves the uncontrolled mobilisation of LTR retrotransposons (LTR-TEs), which are the most abundant class of mobile genetic elements in plant genomes. Here we demonstrate that in conditions inductive for high LTR-TE mobilisation, like abiotic stress in Arabidopsis (Arabidopsis thaliana) and callus culture in rice (Oryza sativa), application of the Reverse Transcriptase (RT) inhibitor known as Tenofovir substantially affects LTR-TE RT activity without interfering with plant development. We observed that Tenofovir reduces extrachromosomal DNA accumulation and prevents new genomic integrations of the active LTR-TE ONSEN in heat-stressed Arabidopsis seedlings, and transposons of Oryza sativa 17 and 19 (Tos17 and Tos19) in rice calli. In addition, Tenofovir allows the recovery of plants free from new LTR-TE insertions. We propose the use of Tenofovir as a tool for studies of LTR-TE transposition and for limiting genetic instabilities of plants derived from tissue culture.