抄録
By carbon-ion irradiation, two independent transparent testa 19 (tt19) mutants were induced. Genetic analysis revealed that tt19 possessed a single recessive mutation on chromosome 5. The characteristics of tt19 mutant are a great reduction of anthocyanin pigments in vegetative parts and of brown pigments in seed coat caused by the oxidation of proanthocyanidins. Map based-cloning enabled us to isolate a single gene, annotated as a glutathione S-transferase-like gene. Disruption of TT19 gene was no effect on the expression of other flavonoid structural genes. Naringenin feeding did not cause anthocyanin pigmentation in tt19, indicating that TT19 could work at any of the anthocyanin biosynthetic steps after the naringenin formation. Vanillin staining illustrated the difference between the wild type and the mutant for the accumulation pattern of proanthocyanidin precursors in immature seed coat. These results suggest that TT19 is involved in relatively last step of both anthocyanin and proanthocyanidin pathway in Arabidopsis.
