Cloning and structural analysis of the anthocyanin pigmentation locus Rt of Petunia hybrida: characterization of insertion sequences in two mutant alleles

Kroon, Johan; Souer, Erik; de Graaff, Alja; Xue, Yongbiao; Mol, Joseph; Koes, Ronald

Abstract

Anthocyanin biosynthesis in flowers of Petunia hybrida is controlled by the regulatory genes an1, an2 and an11. Seven classes of cDNA clones homologous to transcripts that are down-regulated in an1−, an2− and an11− mutants were isolated via differential cDNA cloning. Genetic mapping, antisense RNA experiments and analyses of mutant alleles demonstrated that one class of clones originated from the Rt locus. The rt gene has no introns and encodes a protein with homology to mammalian glucuronosyl transferases and flavonoid 3-O-glucosyl-transferase (UF3GT) encoded by the bz1 gene from Zea mays. As the Rt locus controls the rhamnosylation of reddish anthocyanin-3-O-glucosides which is the first in a series of modifications that finally yield magenta or blue/purple coloured anthocyanins, this suggests that rt encodes an anthocyanin rhamnosyl transferase.

Molecular analysis of two mutant rt alleles showed that their expression is blocked by different DNA insertion elements. Mutability of the rt-vu15 allele results from the presence of a 284 bp transposable element (dTph1) in the rt promoter region, causing a block in transcription. The protein coding region of the rt-r27 allele contains a 442 bp insertion (dTph3) resulting in premature polyadenylation of rt transcripts. Although dTph3 cannot transpose, it has sequence characteristics of transposable elements, suggesting that it is a defective member of a new family of transposable elements.

Citation

Kroon, J., Souer, E., de Graaff, A., Xue, Y., Mol, J., & Koes, R. (1994). Cloning and structural analysis of the anthocyanin pigmentation locus Rt of Petunia hybrida: characterization of insertion sequences in two mutant alleles. The Plant Journal, 5(1), https://doi.org/10.1046/j.1365-313x.1994.5010069.x

• Journal Article Type: Article
• Acceptance Date: Sep 14, 1993
• Online Publication Date: Feb 20, 2003
• Publication Date: Jan 31, 1994
• Deposit Date: Sep 9, 2021
• Journal: Plant Journal
• Print ISSN: 0960-7412
• Electronic ISSN: 1365-313X
• Publisher: Wiley
• Volume: 5
• Issue: 1
• DOI: https://doi.org/10.1046/j.1365-313x.1994.5010069.x
• Public URL: https://durham-repository.worktribe.com/output/1235068