Molecular characterization of mutations induced by gamma irradiation in rice.
In order to analyze mutations induced by gamma irradiation in higher plants, we irradiated rice with gamma rays and screened for mutations expressing phenotypes of glutinous endosperm (wx), chlorophyll b deficiency, endosperm protein deficiency, gibberellin-related dwarfism, and shortened plastochron-in order to clarify types of mutations. Nucleotide sequence analysis showed that the most frequent mutation induced by gamma rays was deletion, particularly small deletion. Of the 24 mutations, 15 were small deletions (1-16 bp), four were large deletions (9.4-129.7 kbp), three were single-base substitutions, and two were inversions. Deletions 100 bp-8 kbp in length were not found, suggesting that gamma irradiation is unlikely to induce deletions of 100 bp to 8 kbp but is more likely to induce deletions between 1 and several ten bp or those of around 10 kbp or more. Based on the results, reverse genetics applications may be possible for gamma irradiation-induced deletions in rice by mismatch cleavage analysis used in Targeting Induced Local Lesions IN Genomes (TILLING) to detect small deletions and base substitutions or by using array comparative genomic hybridization (aCGH) to detect large deletions.
Institute of Radiation Breeding, National Institute of Agrobiological Sciences, 2425 Kamimurata, Hitachi-ohmiya, Ibaraki 319-2293, Japan. ryo622@affrc.go.jp
Ryouhei
R
Morita
Makoto
M
Kusaba
Shuichi
S
Iida
Hiroyasu
H
Yamaguchi
Takeshi
T
Nishio
Minoru
M
Nishimura
D002734:Chlorophyll / Q000172:deficiency; D017931:DNA Primers / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics*; D056625:Endosperm; D005720:Gamma Rays; D017353:Gene Deletion; D005875:Gibberellins / Q000378:metabolism; D005983:Glutens / Q000235:genetics; D018519:Meristem; D009154:Mutation / Q000235:genetics*; D012275:Oryza / Q000235:genetics* / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D018744:DNA, Plant; D005875:Gibberellins; D010940:Plant Proteins; D002734:Chlorophyll; C037184:chlorophyll b; D005983:Glutens