Inheritance of Bluish Flower Color of Transgenic Chrysanthemum by Interspecific Hybrids

Abstract

Bluish transgenic chrysanthemums have already been produced and are expected to be commercialized. As domesticated chrysanthemum (Chrysanthemum morifolium) is known to cross with wild species native to Japan, the risk of transgene flows into the wild population must be considered. However, little research has been conducted on the crossability of transgenic chrysanthemums or on the heritability of the transgenes involved. In this study, we investigated artificial cross-pollination between color-modified chrysanthemums and the wild species Chrysanthemum japonense var. japonense. Relatively high seed set rates of 28.8%-53.5% were achieved. Based on a comparison between the size and shape of the flowerheads and leaves of the seedlings and the parent plant, most seedlings were assumed to be hybrids. Polymerase chain reaction was applied to amplify the Campanula F3'5'H gene fragment. The segregation and inheritance of the transgenes were confirmed. Some transgenic progeny exhibited a modified flower color similar to that of the parent. The progeny were also demonstrated to have accumulated anthocyanins specific to the parent plant. The results confirmed the transmission of the transgenes to the interspecific progeny. The modified anthocyanins then produced petals of similar color. To prevent unintended environmental consequences, techniques are needed to reduce the possibility of transgene flow to native chrysanthemum species. This will be a necessary precursor to the commercialization of bluish chrysanthemums in East Asia, specifically Japan.

Crossability between Transgenic Blue Chrysanthemums and the Wild Chrysanthemum Species <i>Chrysanthemum japonense</i> var. <i>japonense</i>

“…japonense. The use of 'Sei Arabella' or T37 as the pollen parents showed higher seed set rates (from 70.7% to 83.4%) than those obtained with 'Taihei' (from 28.8% to 43.1%, Aida et al 2018). These results demonstrated that cultivated chrysanthemums, including the color-modified transgenic plants, readily cross with C. japonense var.…”

“…For crossing experiments, the ray florets were removed before flowering with the heads being bagged. Given the generally low self-pollination rate of chrysanthemum (Wang et al 2014, Aida et al 2018, pollinations were performed without emasculation. To monitor selfpollination, three bagged heads within each crossing combination were not artificially pollinated.…”

“…Therefore, the risk associated with crossing between wild varieties and genetically modified chrysanthemums must be carefully assessed before the genetically modified chrysanthemums can be commercialized. We have previously reported on the transmission of transgenes from blue chrysanthemums produced using the model host cultivar 'Taihei' to interspecific progeny (Aida et al 2018).…”

Anthocyanins in Floral Colors: Biosynthesis and Regulation in Chrysanthemum Flowers

“…In a recent study, inter-specific crossability of transgenic blue chrysanthemum developed by Noda et al [ 40 ] with the wild species Chrysanthemum japonense var. japonense was checked [ 121 ]. This study demonstrated the heritability of the transgene and confirmed the transmission of the transgene to interspecific progeny.…”

“…Furthermore, the progeny also accumulated anthocyanins that were specific to the parent plant. This provides basic information that may be used to prevent transgene flow to native chrysanthemum species in order to commercialize the blue-hued varieties [ 121 ]. Intriguingly, our work on the breeding of new chrysanthemum cultivars for novel floral colors using inter- and intra-specific breeding has resulted in a large number of cultivars exhibiting alluring flower hues.…”