Characteristics of carbon ion beam induced UVB tolerant and sensitive mutants of rice

Takano, Nao*; Takahashi, Yuko*; Yamamoto, Mitsuru*; Teranishi, Mika*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Hidema, Jun*

To develop gene resources related to UVB tolerance of rice, UVB resistant rice cultivar Sasanishiki was irradiated with carbon ion beams and successfully isolated two mutant lines: UVB resistant UVTSa-319 and UVB sensitive UVSSa-1. These mutants have similar levels of the amount of UV-absorbing compounds and the repair activities of cyclobutane pyrimidine dimers and (6-4) photoproducts which have been thought as factors related to UVB tolerance in Sasanishiki. We performed Array CGH to estimate mutated region and found that an approximate 40 kbp region on chromosome 7 containing 2 unknown genes was deleted in UVTSa-319. Also, the mutant UVSSa-1 had a deletion on chromosome 7 covering 2 other genes. Next, to deduce the relationships between deleted genes and UVB tolerant mechanism in these mutants, microarray analyses were performed using RNAs of Sasanishiki and these mutants. We discuss the functions of deleted genes and relationships of UVB tolerance or sensitivity.