A novel wx mutation caused by insertion of a retrotransposon-like sequence in a glutinous cultivar of rice (Oryza sativa).
DNA polymorphism of the Wx gene in glutinous rice cultivars was investigated by PCR-RF-SSCP and heteroduplex cleavage analysis using Brassica petiole extract, and the nucleotide sequence variations were identified. Most japonica-type glutinous rice was found to have a 23-bp duplication in the second exon, which causes loss of the function of granule-bound starch synthase (GBSS) encoded by the Wx gene. Without the 23-bp duplication, there was an insertion of 7,764 bp in the ninth exon of the wx allele of 'Oragamochi'. Expression analysis of the wx allele using RT-PCR and Northern blot analysis revealed that transcripts of the 'Oragamochi' wx allele are about 1-kb shorter and that the deduced amino acid sequence of the transcript lacks a motif important for GBSS. Therefore, this insertion was considered to be the cause of the glutinous trait of 'Oragamochi'. This 7,764-bp insertion had long terminal repeats, a primer binding site, and a polypurine tract, but no sequence homologous with gag and pol, suggesting that it is a non-autonomous element. Furthermore, it had a structure similar to Dasheng and may be a member of Dasheng.
Hori
Y
Y
Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoba-ku, Sendai, 981-8555, Japan.
Fujimoto
R
R
Sato
Y
Y
Nishio
T
T
D000483:Alleles; D020816:Amino Acid Motifs; D015152:Blotting, Northern; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000196:embryology / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000737:chemistry; D018626:Retroelements; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics; D013214:Starch Synthase / Q000235:genetics*
D010940:Plant Proteins; D012333:RNA, Messenger; D018626:Retroelements; D013214:Starch Synthase