Overexpression of carotenogenic genes in the Japanese morning glory <i>Ipomoea</i> (<i>Pharbitis</i>) <i>nil</i>
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Japanese morning glory, <i>Ipomoea nil</i>, has several coloured flowers except yellow, because it can accumulate only trace amounts of carotenoids in the petal. To make the petal yellow with carotenoids, we introduced five carotenogenic genes (<i>geranylgeranyl pyrophosphate synthase</i>, <i>phytoene synthase</i>, <i>lycopene</i> β-<i>cyclase</i> and β-<i>ring hydroxylase</i> from <i>Ipomoea obscura</i> var. <i>lutea</i> and bacterial <i>phytoene desaturase</i> from <i>Pantoea ananatis</i>) to white-flowered <i>I. nil</i> cv. AK77 with a petal-specific promoter by <i>Rhizobium</i> (<i>Agrobacterium</i>)-mediated transformation method. We succeeded to produce transgenic plants overexpressing carotenogenic genes. In the petal of the transgenic plants, mRNA levels of the carotenogenic genes were 10 to 1,000 times higher than those of non-transgenic control. The petal colour did not change visually; however, carotenoid concentration in the petal was increased up to about ten-fold relative to non-transgenic control. Moreover, the components of carotenoids in the petal were diversified, in particular, several β-carotene derivatives, such as zeaxanthin and neoxanthin, were newly synthesized. This is the first report, to our knowledge, of changing the component and increasing the amount of carotenoid in petals that lack ability to biosynthesize carotenoids.
- Plant Biotechnology
Plant Biotechnology 34(4), 177-185, 2017
Japanese Society for Plant Cell and Molecular Biology