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Low-energy-ion (10-200 KeV) irradiation has been proven to have a wide range of biological effects and led to fruitful achievements as a new mutagenic source for genetic modification. Nevertheless, the mutation mechanism of low-energy-ions due to their short penetrating power in biological tissues is still under debates. Scientists from the Institute of Technical Biology and Agricultural Engineering (ITBAE) have reported a radiation-induced bystander effect shedding lights on the mutation mechanism of low-energy-ion irradiation. (Radiation Research, 2007, 2008, 2010). Sponsored by the National Science Fund of China and the Key Innovative Project of Chinese Academy of Sciences, Dr Bian’s group from ITBAE made important progress in studying the time course of long-distance signaling in plants.
Dr. Bian’s group developed a root micro-grafting technique for young seedlings of Arabidopsis thaliana, by which the bystander signaling communication of root-to-shoot could be easily stopped or started at some deliberately chosen time points after root irradiation. With this technique, Ting Wang, Fanghua Li et al. demonstrated the time course of long-distance signaling in plants. Briefly, an 8-hr accumulation of damage signals in bystander parts after irradiation is essential for eliciting a bystander response. The protraction on signal accumulation is not related to the transmitting speed of signaling molecules in plants, and does not result from the delayed initiation of bystander signals in targeted root cells either. It is suggested that the bystander effect might be induced jointly by multiple bystander signals initiated at different stages after irradiation. Moreover, reactive oxygen species (ROS) are shown to be implicated in the response process of bystander cells to radiation damage signals, rather than in the generation of bystander signals in targeted cells.
This work establishes the research foundation for further elucidating the chemical nature of the radiation damage signals and the implicated biological pathways; and the results will be published in Radiation Research. |
