title: Tissue culture-induced flower-color changes in Saintpaulia caused by excision of the transposon inserted in the flavonoid 3', 5' hydroxylase (F3'5'H) promoter.
abstract: The variegated Saintpaulia cultivar Thamires (Saintpaulia sp.), which has pink petals with blue splotches, is generally maintained by leaf cuttings. In contrast, tissue culture-derived progeny of the cultivar showed not only a high percentage of mutants with solid-blue petals but also other solid-color variants, which have not been observed from leaf cuttings. Solid-color phenotypes were inherited stably by their progeny from tissue culture. Petals from each solid-color variant were analyzed by high-performance liquid chromatography and shown to contain different proportions of three main anthocyanin derivatives: malvidin, peonidin, and pelargonidin. Analysis of flavonoid 3', 5'-hydroxylase (F3'5'H) sequences showed no differences in the coding region among the variants and variegated individuals. However, a transposon belonging to the hAT superfamily was found in the promoter region of variegated individuals, and the presence of transposon-related insertions or deletions correlated with the observed flower-color phenotypes. Solid-blue flower mutants contained 8-base pair (bp) insertions (transposon excision footprints), while solid-pink mutants had 58- to 70-bp insertions, and purple- and deep-purple mutants had 21- and 24-bp deletions, respectively. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis showed that F3'5'H expression levels correlated with insertions and deletions (indels) caused by hAT excision, resulting in flower-color differences. Our results showed that tissue culture of Saintpaulia 'Thamires' elicits transposon excision, which in turn alters F3'5'H expression levels and flower colors.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawabe
authors.forename: Munetaka
authors.initials: M
authors.lastname: Hosokawa
authors.forename: Fumi
authors.initials: F
authors.lastname: Tatsuzawa
authors.forename: Motoaki
authors.initials: M
authors.lastname: Doi
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements; D018076:DNA, Complementary / Q000235:genetics; D035264:Flowers / Q000737:chemistry / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D054643:INDEL Mutation; D019684:Magnoliopsida / Q000737:chemistry / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010860:Pigments, Biological / Q000096:biosynthesis*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D046509:Tissue Culture Techniques
chemical_list: D000872:Anthocyanins; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D010860:Pigments, Biological; D010940:Plant Proteins; D003577:Cytochrome P-450 Enzyme System; C084258:flavonoid 3',5'-hydroxylase