Apr. 25, 2006

The Japan Atomic Energy Agency (President Yuichi Tonozuka, hereafter referred to as JAEA) revealed that the DNA content in leaf cells is important for Ultraviolet (UV) light tolerance of plants from the analyses of UV-tolerant mutant induced by ion beams. This is a research achievement of Dr. Yoshihiro Hase, Gene Resource Research Group, Quantum Beam Science Directorate and Dr. Atsushi Tanaka, Unit Manager of Radiation-Applied Biology Division, Quantum Beam Science Directorate.

Since the increase in solar UV light by depletion of ozone layer is affecting crop production, it becomes an important subject to reveal the protection mechanism of plants from UV light. It has been thought that the UV-absorbing pigment such as anthocyanin in leaves and the ability for repairing DNA damages are important for UV tolerance of plants. The JAEA previously succeeded in isolating UV-tolerant Arabidopsis mutant induced by ion beam irradiation at the ion beam facility (TIARA) in the Takasaki Advanced Radiation Research Institute. From the analyses of this mutant, we revealed a novel mechanism to protect plants from UV light. In this mutant, DNA content in leaf cells has increased compared to that in wild type due to the stimulated endoreduplication. The increased DNA content, i.e., the increased number of gene copies compensates the repression of cell activity by UV-induced damages. Consequently, this mutant shows better growth by more than two times compared with the wild type.

The present result is expected to be utilized to produce UV-resistant crops such as wheat, soybean, etc., and to protect ornamental plants from leaf burn. This result is also important to understand how the plants have adapted to solar UV environment up to now. This result has been published in The Plant Journal 46(2), 317-326 (2006).

  
  
  

•Novel mechanism to protect plants from UV light -Plants could be more UV tolerant by increasing DNA content-
•Supplementary document
•Glossary