Abstract:
Heavy ion irradiation has unique physical and biological characteristics and has been widely applied in crop and bacteria mutation breeding. However, the mechanism underlying heavy ion irradiation mutagenesis is not completely clear. Unlike the conventional X and
\gamma ray, heavy ion irradiation has a high linear energy transfer(LET) and mainly induces clustered DNA damage, the evolution of which to genetic variation is more complex and mutation types are more difficult to predict. Due to the limitation of experimental techniques, it is difficult to localize the DNA target of heavy ions at the level of DNA sequence. To address this issue, we first constructed a homologous recombination(HR) element of tetracycline resistance gene (
TetA) in light of high abundance of DNA double strand breaks(DSB) in the core of heavy ion radiation-induced cluster damage. And the DSB specific response of HR. We then linked a reverse mutation screening gene lacI to the
TetA recombination elements to detect cluster damage-derived mutations. Finally, this plasmid was transformed into E.coli. Based on this experimental system we comparatively analyzed
TetA recombinations and mutations of
LacI gene after irradiation with
\gamma -ray and carbon heavy ions (80 MeV/u). We preliminarily verified the feasibility of this research strategy and provided a methodological foundation for further investigation of the mechanisms underlying heavy ion radiation mutagenesis.