Linear DNA intermediates of the Tto1 retrotransposon in Gag particles accumulated in stressed tobacco and Arabidopsis thaliana.
The active transcription of some plant retrotransposons under diverse stress conditions suggests active transposition. However, transposition has been demonstrated only during tissue/cell culture. To examine whether transposition is activated under conditions other than tissue/cell culture, DNA intermediates for retrotransposition of the tobacco retrotransposon Tto1 were analysed. Using transgenic Arabidopsis callus expressing high levels of Tto1 RNA in a ddm1 hypomethylation mutant background, the existence of extrachromosomal Tto1 linear DNA molecules in a Gag-particle fraction was demonstrated. By combination with ligation-mediated PCR amplification, we detected Tto1 linear DNA molecules in particle fractions from callus and methyl jasmonate-treated leaves of tobacco, but not from non-stressed leaves. Tto1 DNA intermediates could not be detected in the tobacco corolla where Tto1 is expressed. These results indicate that the transcriptional activation of Tto1 by defence-related stresses leads to the synthesis of DNA intermediates, whereas post-transcriptional suppression of Tto1 activity is suggested in the corolla.
Takeda
S
S
Molecular Genetics Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
Sugimoto
K
K
Kakutani
T
T
Hirochika
H
H
D000941:Antigens / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics*; D018744:DNA, Plant / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D018749:RNA, Plant / Q000096:biosynthesis; D018626:Retroelements / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*
D000941:Antigens; D018744:DNA, Plant; D018749:RNA, Plant; D018626:Retroelements