Crossbreeding of a metallic color carnation and diversification of the peculiar coloration by ion-beam irradiation

Abstract

In general, carnations (Dianthus caryophyllus) have each of four kinds of anthocyanins acylated by malic acid. A few carnation cultivars are known to display a peculiar dusky color supposedly caused by anthocyanic vacuolar inclusions (AVIs). The hereditary pattern suggests that the peculiar color is controlled by a single recessive factor tightly linked with existence of AVIs containing non-acylated anthocyanins. To diversify the peculiar color carnation, we produced a bluish purple line displaying a highly novel metallic appearance by crossbreeding. By subjecting the line to ion-beam irradiation, we generated metallic reddish purple, metallic crimson and metallic red lines. The major anthocyanin of the metallic bluish purple and reddish purple lines was pelargonidin 3,5-diglucoside, whereas that of the metallic crimson and red lines was pelargonidin 3-glucoside. All four metallic lines did not have transcripts for anthocyanin malyltransferase. Metallic crimson and red lines did not express the acyl-glucosedependent anthocyanin 5-O-glucosyltransferase gene. In contrast to the dusky color types, metallic lines have highly condensed AVIs and water-clear vacuolar sap in the petal adaxial epidermal cells. Differences in the number of AVIs on the abaxial side were observed within mutants containing the same anthocyanin, thereby affecting their shade and hue. We demonstrated that (1) a factor generating the AVIs is inactivated anthocyanin malyltransferase gene, (2) AVIs in water-clear vacuolar sap in the adaxial epidermal cells generate the novel metallic appearance, and (3) ion beam breeding is a useful tool for increasing metallic colors by changing anthocyanin structure and the level of AVIs.

Tissue-dependent somaclonal mutation frequencies and spectra enhanced by ion beam irradiation in chrysanthemum

“…Reductions in nuclear DNA content were positively correlated with reductions in plant height. We previously demonstrated the effectiveness of combining tissue-cultured plants with ion beam irradiation to generate mutants and for breeding carnation cultivars (Okamura et al 2006(Okamura et al , 2013. In the present report, we address the issue of tissue source-dependent differences in the frequency and spectrum of mutations by assessing changes in flower color for a large number of chrysanthemum somaclones and ion-beam irradiated clones and suggest ways to make mutation breeding a more logical, directed and reliable technology.…”

“…Both types of change result in null mutations . It is plausible that ion beams induce a limited amount of irreparable DNA damage (Shikazono et al 2009) leading to the production of stable mutants with desired traits while at the same time not causing other undesirable mutations (Okamura et al 2003(Okamura et al , 2013.…”

Relationship between the velvet-like texture of flower petals and light reflection from epidermal cell surfaces

“…The authors concluded that epidermal cell shape influenced petal colour by focusing light onto the pigments. Recent studies show that highly condensed anthocyanic vacuolar inclusions and colourless vacuolar sap in the adaxial epidermal cells of the petal lead to the metallic luster texture of petal in carnation (Okamura et al 2013). These findings suggested that the optical properties of the tissue surface likely influence the perceived colour and texture.…”

Biological effects of ion beam irradiation on perennial gentian and apple

“…This result implied that both C and Ne ion beams caused large deletions of genomic regions rather than substitutions, insertions, or deletions of only one or a few nucleotides. In previous studies, ion bean irradiation caused the deletion of a large genomic region in carnation (Okamura et al 2013) and several kinds of mutations such as single nucleotide substitutions, small and large insertion and deletions, and genomic rearrangements in Arabidopsis (Kazama et al 2011(Kazama et al , 2013. Ion beams can also induce large genomic alterations such as chromosomal rearrangements (Sakamoto et al 2017).…”