Breeding glittering carnations by an efficient mutagenesis syst

Abstract

We have developed a systematic and directed method to create novel glittering mutants in carnation (Dianthus caryophyllus) by combining the advantages of ion-beam breeding and genomic information. e method is a series of steps that include: (i) establishing a basic strategy to select appropriate genotypes for speci c breeding aims using genomic information, (ii) identifying factors that induce anthocyanic vacuolar inclusions (AVIs), (iii) using ion-beam irradiation consecutively to modify pigment glycosylation and/or acylation, (iv) tuning shading of color, and (v) selecting stable mutants with markers. During the course of this work, we identi ed a factor that causes AVIs and analyzed the content of anthocyanins and related compounds in the owers of these mutants. Applying the method, we have created two highly novel carnations with the most glittering color ever reported. Key words:Anthocyanin, carnation, ion-beam irradiaton, mutation breeding, glittering.Ion-beam breeding, a newly established breeding technique, has become an important tool for producing novel and unique mutants that cannot be obtained by conventional mutagenesis methods (Okamura et al. 2003;Tanaka et al. 2010). Flower color is an important characteristic in the floriculture industry, and novel colors create a positive economic impact. A wide variety of ower colors can be derived from only six types of anthocyanin aglycones that change color a er modi cation with glycosyl and/or acyl moieties. For breeding colors in otherwise superior cultivars, mutation breeding especially with ion beams is among the best choices because it alters only a few traits and retains other characteristics of the original cultivars. In this review, we describe measures to select appropriate materials to make desired mutants using genomic information, improved procedures of ion-beam irradiation, and their application to carnation (Dianthus caryophyllus), one of the world's most important oricultural crops. We also report our success in creating highly novel oricultural varieties; that is, carnations with glittering colors in the true sense of the word. In addition, several factors relevant to the novel phenotypes have been discovered such as pigment constituents, genes and morphological characteristics of petal cells. Basis for breeding glittering carnations using genomic information and mutagenesisCarnation varieties have been created mainly by cross-breeding, partially combined with spontaneous mutation. However, due to its heterozygous genetic background, being heterozygous at many di erent loci throughout the genome, conventional cross breeding o en produces a huge number of undesired individuals in segregating population. erefore, it is quite laborious to obtain a desired individual that combines the good characteristics of the parents used in the cross. Moreover, it is quite rare to improve only a few traits in otherwise superior varieties. Now, genetic manipulations have been successfully applied to develop a blue carnation containing delphinidin, a pi...

Information on Flower Coloration and Pigmentation in Current Carnation Cultivars for Use in Future Flower-color Breeding

“…According to the chromatographic analysis, cyaniccolored carnations basically had one major anthocyanin type in the petals and accumulated either Pg-or Cybased anthocyanins dominantly as reported in previous studies (Ootani and Miura, 1961;Okamura et al, 2012Okamura et al, , 2013. This study also indicated that no carnation cultivars except for a variegated carnation 'Pink Montezuma' (No.…”

“…Orange flowers arise due to the coexistence of Pg-based anthocyanin and Ch2'G (Gonnet and Hieu, 1992;Morimoto et al, 2019). There are a handful of commercial carnations that display colors distinct from general carnations, and the wellknown dusky-purple-flowered carnation 'Nazareno' has a deacyl anthocyanin, pelargonidin 3,5-O-diglucoside (Pg3,5dG), as the major flower pigment (Okamura et al, 2012). There are other carnations with distinct flower colors that have been generated by ion-beam breeding and these varieties accumulate either pelargonidin 3-O-glucoside (Pg3G), cyanidin 3-O-glucoside (Cy3G) or cyanidin 3,5-O-diglucoside (Cy3,5dG) (Nakayama et al, 2012;Okamura et al, 2013).…”

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

“…Pigment inclusions were investigated in several flower species and referred to as anthocyanic vacuolar inclusions or AVIs (Markham et al 2000). However, information on the relationship between AVIs and peculiar colors is limited (Morita et al 2005, Zhang et al 2006, and there are no reports on the hereditary pattern of peculiar coloration and AVIs other than our preliminary report (Okamura et al 2012). Furthermore, there are very few kinds of peculiar color phenotypes in carnation.…”

“…2a). We further tried to diversify the metallic flower color by the ion-beam breeding technique (Okamura et al 2012). Petal segments of 'Line A' were irradiated with 320 MeV carbon ions and cultured in vitro to obtain regenerated plants.…”

Comprehensive analyses of anthocyanin and related compounds to understand flower color change in ion-beam mutants of cyclamen (Cyclamen spp.) and carnation (Dianthus caryophyllus)

“…Each anthocyanin is responsible for a speci c ower color (Figure 4) as described in another review described by Okamura et al (2012) in this issue. In our work, mutants containing a non-acylated anthocyanin corresponding to each of the carnation ower anthocyanins, pelargonidin 3-glucoside (Pg3G) (Figure 4E), cyanidin 3-glucoside (Cy3G) (Figure 4F), pelargonidin 3,5-diglucoside (Pg3,5dG) ( Figure 4G), and cyanidin 3,5-diglucoside (Cy3,5dG) ( Figure 4H), were obtained by loss of the acylation enzyme (Abe et al 2008) and glucosyltranferase (Matsuba et al 2010) activities by ion-beam irradiation (Okamura et al 2003).…”