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- Title
Molecular Characterization of Granule-Bound Starch Synthase (GBSSI) gene of Waxy Locus Mutants in Japonica Rice (Oryza saliva L.).
- Authors
Sohn, Seong-Han; Rhee, Yong; Hwang, Duk-Ju; Lee, Sok-Young; Lee, Jung-Ro; Lee, Yeon-Hee; Shin, Young-Seop; Jeung, Ji-Ung; Kim, Myung-Ki
- Abstract
Five mutants were investigated at the molecular level to determine the factors responsible for mutated endosperm types. They were classified as high (HA) or low amylose (LA) phenotypes based on the amylose content in endosperm. The five were previously produced from Ilpum and Shindongjin cultivar treated with N-methyl-N-nitrosourea and gamma-ray irradiation, respectively. Analysis of the genomic structure and expression of Granule-bounded Starch Synthase I (GBSSI) genes revealed that mutants generally showed a higher incidence of nucleotide transition than transversion, and the A:T→G:C transition was particularly prevalent. The rates of nucleotide substitution in HA mutants were generally higher than those in the LA mutants, leading to higher substitutions of amino acid in the HA mutants. Neither nucleotide substitutions interfering with intron splicing or causing early termination of protein translation were found, nor any large-sized deletions or additions were found in all the mutants. In principle, amylase content can be regulated by three factors: internal alterations of GBSSI protein, the strength of gene expression, and other unknown external factors. Our results indicate that the endosperm mutants from Shindongjin arose from internal alterations of GSSI proteins, which may be the result of amino acid substitutions. On the other hand, the Ilpum mutants might be principally caused by the alteration of gene expression level. Analysis of another three glutinous cultivars revealed that the major factor leading to glutinous phenotypes is the 23-bp duplicative motif (5'-ACGGGTTCCAGGGCCTCAAGCCC-3') commonly found in exon 2, which results in the premature termination of protein translation leading to the production of a non-functional GBSSI enzyme.
- Subjects
STARCH; ORYZA; LOCUS (Genetics); GENETIC mutation; ENDOSPERM; PHENOTYPES
- Publication
Korean Journal of Breeding Science, 2010, Vol 42, Issue 1, p1
- ISSN
0250-3360
- Publication type
Article