title: UVB sensitivity and cyclobutane pyrimidine dimer (CPD) photolyase genotypes in cultivated and wild rice species.
abstract: We investigated the UVB-sensitivity in 12 rice strains belonging to two cultivated species (O. sativa and O. glaberrima) and three wild species (O. barthii, O. meridionalis and O. rufipogon) of rice possessing the AA genome, while focusing on the CPD photolyase activity and the genotypes of CPD photolyase. Although the UVB sensitivity, CPD photolyase activity, and CPD photolyase genotype varied widely among these rice species, the sensitivity to UVB radiation depended on the activity of the CPD photolyase, regardless of grass shape, habitat, or species. The rice strains examined here clearly divided into three groups based on the CPD photolyase activity, and the activity of the strains greatly depended on amino acid residues at positions 126 and 296, with the exception of the W1299 strain (O. meridionalis). The amino acid residues 126 and 296 of CPD photolyase in Sasanishiki strain (O. sativa), which showed higher enzymatic activity and more resistance to UVB, were glutamine (Gln) and Gln, respectively. An amino acid change at position 126 from Gln to arginine ("Nori"-type) in the photolyase led to a reduction of enzymatic activity. Additionally, an amino acid change at position 296 from Gln to histidine led to a further reduction in activity. The activity of the W1299 strain, which possesses a "Nori"-type CPD photolyase, was the highest among the strains examined here, and was similar to that of the Sasanishiki. The CPD photolyase of the W1299 contains ten amino acid substitutions, compared to Sasanishiki. The alterations in amino acid residues in the W1299 CPD photolyase compensated for the reduction in activity caused by the amino acid substitutions at positions 126. Knowledge of the activity of different CPD photolyase genotypes will be useful in developing improved rice cultivars.
authors.affiliation: Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Iwamatsu
authors.forename: Chizuru
authors.initials: C
authors.lastname: Aoki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takahashi
authors.forename: Mika
authors.initials: M
authors.lastname: Teranishi
authors.forename: Yuanying
authors.initials: Y
authors.lastname: Ding
authors.forename: Chuanqing
authors.initials: C
authors.lastname: Sun
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kumagai
authors.forename: Jun
authors.initials: J
authors.lastname: Hidema
mesh_terms: D000595:Amino Acid Sequence; D004249:DNA Damage; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000235:genetics*; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation / Q000235:genetics / Q000528:radiation effects; D005838:Genotype; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000254:growth & development / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics*; D017354:Point Mutation; D011740:Pyrimidine Dimers / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014466:Ultraviolet Rays
chemical_list: D010940:Plant Proteins; D011740:Pyrimidine Dimers; D004255:Deoxyribodipyrimidine Photo-Lyase