ARS | Publication request: Genotype dependent burst of transposable element expression in crowns of hexaploid wheat (Triticum aestivum L.) during cold acclimation

Submitted to: Comparative and Functional Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2011
Publication Date: February 29, 2012
Citation: Chingcuanco, D.L., Fowler, B.D. 2012. Genotype dependent burst of transposable element expression in crowns of hexaploid wheat (Triticum aestivum L.) during cold acclimation. Comparative and Functional Genomics. Available at: http://www.hindawi.com/journals/cfg/2012/232530/. doi:10.1155/2012/232530..

Interpretive Summary: Transposable elements (TEs) make up a substantial fraction of plant genomes and have been shown to serve as a major contributor of genetic variations. To prevent the potentially harmful effects of TE activities, the host plant has evolved several mechanisms to repress TE expression. The molecular bases of these mechanisms are beginning to unfold but are still not clearly understood. How the host suppresses and reactivates the expression of TEs in its genome is a key issue in genome biology. It has been proposed that the theory of punctuated equilibria in evolutionary biology results from the epigenetic control of TE expression. Our data provides insights into how TEs are regulated in planta. Our result indicates that TE expression in wheat could be induced in a genotype and developmental stage specific manner during cold treatment and suggests a potential role of the flowering locus, Vrn-A1, in this process.

Technical Abstract: The expression of 1,613 transposable elements (TEs) represented in the Affymetix Wheat Genome Chip was examined during cold treatment in crowns of 4 hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throughout the experiment in three of the genotypes. In winter Norstar, the most cold-hardy of the four genotypes, a subset of the TEs showed a burst of expression after vernalization saturation was achieved. About 47% of the TEs were expressed and both Class I (retrotransposons) and Class II (DNA transposons) types were well represented. Gypsy and Copia were the most represented among the retrotransposons while CACTA and Mariner were the most represented DNA transposons. The data suggests that the Vrn-A1 region plays a role in the stage specific induction of TE expression in this genotype.