An siRNA pathway prevents transgenerational retrotransposition in plants subjected to stress

Article Article scientifique Article An siRNA pathway prevents transgenerational retrotransposition in plants subjected to stress eng 2011 author Ito Hidetaka 651304 author Gaubert Hervé 670560 author Bucher Etienne 651582 author Mirouze Marie 646829 author Vaillant Isabelle 650125 author Paszkowski Jerzy 134849 115-119 10.1038/nature09861 21399627 0028-0836 http://www.nature.com/nature/journal/v472/n7341/full/nature09861.html Eukaryotic genomes consist to a significant extent of retrotransposons that are suppressed by host epigenetic mechanisms, preventing their uncontrolled propagation. However, it is not clear how this is achieved. Here we show that in Arabidopsis seedlings subjected to heat stress, a copia-type retrotransposon named ONSEN (Japanese 'hot spring') not only became transcriptionally active but also synthesized extrachromosomal DNA copies. Heat-induced ONSEN accumulation was stimulated in mutants impaired in the biogenesis of small interfering RNAs (siRNAs); however, there was no evidence of transposition occurring in vegetative tissues. After stress, both ONSEN transcripts and extrachromosomal DNA gradually decayed and were no longer detected after 20-30 days. Surprisingly, a high frequency of new ONSEN insertions was observed in the progeny of stressed plants deficient in siRNAs. Insertion patterns revealed that this transgenerational retrotransposition occurred during flower development and before gametogenesis. Therefore in plants with compromised siRNA biogenesis, memory of stress was maintained throughout development, priming ONSEN to transpose during differentiation of generative organs. Retrotransposition was not observed in the progeny of wild-type plants subjected to stress or in non-stressed mutant controls, pointing to a crucial role of the siRNA pathway in restricting retrotransposition triggered by environmental stress. Finally, we found that natural and experimentally induced variants in ONSEN insertions confer heat responsiveness to nearby genes, and therefore mobility bursts may generate novel, stress-responsive regulatory gene networks. Arabidopsis/genetics/growth & development/physiology Arabidopsis Proteins/genetics Chromosomes, Plant DNA, Plant/genetics Gene Expression Regulation, Plant/genetics Gene Regulatory Networks/genetics Genes, Plant/genetics Heat-Shock Response/genetics Models, Genetic Mutagenesis, Insertional/genetics RNA, Plant/genetics RNA, Small Interfering/genetics Retroelements/genetics Seedling/genetics Transcription, Genetic/genetics Dewey 580 45 Département des sciences végétales 163 false Nature 472 7341 27277b5e-91f8-4e4a-99ed-5c46d953cc2f Article (Published version) Restricted Ito_Nature_2011.pdf 505523 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département des sciences végétales

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An siRNA pathway prevents transgenerational retrotransposition in plants subjected to stress	Nature			2011	556	0

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