Spontaneous Mutations of the Flavonoid 3′-hydroxylase Gene Conferring Reddish Flowers in the Three Morning Glory Species

Abstract

;Among the Ipomoea plants, both Ipomoea nil and Ipomoea tricolor display bright blue flowers, and Ipomoea purpurea exhibits dark purple flowers. While all of these flowers contain cyanidin-based anthocyanin pigments, the mutants of I. nil, I. purpurea, and I. tricolor carrying the magenta, pink, and fuchsia alleles, respectively, produce reddish flowers containing pelargonidin derivatives, and all of them are deficient in the gene for flavonoid 3¢-hydroxylase (F3¢H). The magenta allele in I. nil is a nonsense mutation caused by a single C to T base transition generating the stop codon TGA, and the cultivar Violet carries the same mutation. Several tested pink mutants in I. purpurea carry inserts of the 0.55-kb DNA transposable element Tip201 belonging to the Ac/Ds superfamily at the identical site. No excision of Tip201 from the F3¢H gene could be detected, and both splicing and polyadenylation patterns of the F3¢H transcripts were affected by the Tip201 integration. The fuchsia allele in I. tricolor is a single T insertion generating the stop codon TAG, and the accumulation of the F3¢H transcripts was drastically reduced by the nonsense-mediated RNA decay. Spontaneous mutations in Ipomoea, including a possible founder mutation in the pink allele, are also discussed.

Cloning of the Flavonoid 3&apos;-Hydroxylase Gene of <i>Eustoma grandiflorum</i> (Raf.) Shinn. (<i>EgF3&apos;H</i>) and Complementation of an F3&apos;H-deficient Mutant of <i>Ipomoea nil</i> (L.) Roth. by Heterologous Expression of <i>EgF3&apos;H</i>

“…In the present study, we successfully isolated the F3'H cDNA from lisianthus flowers and confirmed its function as a flavonoid 3'-hydroxylase that functions in cyanidin synthesis by transgenic complementation of the heterologous plant species I. nil cultivar 'Violet', which has a magenta mutation that eliminates F3'H activity (Hoshino et al, 2003).…”

“…4) because an authentic magenta mutant of this species, I. nil 'Violet', has a nonsense point mutation in the F3'H gene (Hoshino et al, 2003). We successfully demonstrated that the lisianthus F3'H gene encodes a flavonoid 3'-hydroxylase that plays a role in anthocyanin production.…”

“…1); however, the first 35 amino acid residues and the region between residues 263 and 274 varied among these F3'Hs. The deduced amino acid sequences of EgF3'H share 384/511 (75.1%), 347/509 (68.2%), and 378/512 (73.8%) identical residues with those of P. hybrida (Brugliera et al, 1999) (AF155332), A. thaliana (Schoenbohm et al, 2000) (AL133421), and I. nil (Hoshino et al, 2003) (AB113261), respectively. A phylogenetic tree of plant F3'H and F3'5'H proteins is shown in Figure 2.…”

“…4A) (Hoshino et al, 2003). We utilized this genetic trait of the latter strain to determine whether the cloned EgF3'H was active; specifically, the 35S::EgF3'HCR chimeric gene was introduced into I. nil 'Violet' by Agrobacterium-mediated transformation.…”

Identification of a Novel Mutant <i>pAMT</i> Allele Responsible for Low-pungency and Capsinoid Production in Chili Pepper: Accession ‘No. 4034’ (<i>Capsicum chinense</i>)

“…The mechanism exists in all eukaryotes, and the involvement of NMD in the reduction of gene expression in plants also has also reported in inactive alleles of anthocyanin biosynthetic genes. The expression level of inactive anthocyanin biosynthetic gene alleles containing premature stop codons was significantly reduced in the morning glory and onion (Hoshino et al, 2003;Kim et al, 2009).…”