Study of Genomic Instability of Arabidopsis Thaliana Induced by Lowenergyion Radiation

Key words: 
• lowenergy ion irradiation /
• somatic homologous recombination /
• instability of genome

Abstract: The somatic homologous recombination was frequently used to evaluate genome stability because it can result in DNA changes， such as rearrangement， deletion and duplication. In this paper， we used Arabidopsis thaliana transgenic for GUS recombination substrate (R2L100 and R3L66) to study the genomic instability induced by low energy ion and α particle characteristic of shortpenetrating properties. The dry seeds of R3L66 line were irradiated by 30 keV Argon ion， the Homologous Recombination Frequency (HRF) had a significant increase at dose range of 500×1013—3 000×1013 ions/cm2. The highest level of HRF was 2.42fold over the control. The 3.3 MeV α particles were used to radiate 4dayold seedlings of R2L100 line. The HRFs had a dosedependent increase at dose of 1—10 Gy， and a dosedependent decrease at 10—100 Gy. The highest level of HRF induced by α particle was 1.9fold over control at the dose of 10 Gy. These results indicate that shortpenetrating irradiation can effectively trigger the plant genomic instability at the level of plant. The local irradiation on the roots of R2L100 by α particle resulted in a 2.5fold increase of HRF in nonirradiated aerial plant，which indicates that a signal of genomic instability generated by α particle radiation can systemically travel in whole plant. It is possible that the genome instability induced by lowenergy ion is a major part of its mutagenic mechanism.