Low-energy ion beam promotes the transcription and transposition of the Copia-retrotransposons in wheat (Triticum aestivum L.)

Abstract

LTR-retrotransposons are genetic elements having the direct long terminal repeats (LTRs). It can move via an RNA intermediate within genomes and is an important fraction of eukaryote genomes. Low-energy N(+) ion beam promoted the transcription of the copia-retransposons in those wheat (cv. 'Zhoumai 16', which were radiated and allowed to grow for 24 h and 48 h from the planting. Relative expression ratio of the copia-retransposons was elevated in different degrees (with a max 40 fold) in wheat plants treated with different doses of N(+) beam, comparing to that in the controls. The molecule markers of the IRAP and REMAP to the DNA isolated from the 14-d leaves of wheat plants treated with the low-energy N(+) beam showed that the transposition of some copia-retransposons was re-activated. The enhanced transcription of the copia-retransposons in wheat could weaken or enhance the expression of their nearby genes. The transposition of the retrotransposon in genome can change the primary structure of the functional DNA fragments of chromosomes, and it can also be visualized as the appearance of a new phenotype of plants. In the mid 1980s, the biological effects of low-energy ion beam were recognized and demonstrated experimentally. Hence, it suggests that the enhanced transcription and the re-activated transposition of the retrotransposons are partially attributed to the biological effect of low-energy ion beam.