Abstract
A binary vector containing an Antirrhinum majus UDP-glucose:flavonoid-3- O-glucosyltransferase (UFGT) cDNA under the control of the cauliflower mosaic virus 35S promoter was used to transform lisianthus ( Eustoma grandiflorum Grise.). Of four independent transgenic lines recovered, one produced high levels of the UFGT transcript and synthesized 3- O-glucosylated anthocyanins novel to lisianthus, as well as enhanced levels of 3- O-glucosylated flavonols. The novel 3- O-glucosylated anthocyanins accounted for approximately 30% of the total anthocyanins in the petals. The level of 3- O-glucosylated flavonols increased by approximately 4.8 x, representing a change from the production of 3- O-galactosylated flavonols to 3- O-glucosylated flavonols of approximately 32%. In addition, the increase in glucosylation of the flavonols resulted in a corresponding decrease in acylation. Modifications at other positions of the flavonoid nuclei were unaffected. The results indicate that in lisianthus there is a high specificity shown by some flavonoid modifying enzymes, such as that for flavonol acylation, while other enzymes, such as those involved in modifications at the C-5 of the anthocyanin, are more flexible in their choice of substrate. The results also provide information on the role of flavonoid glycosylation and acylation in copigmentation in lisianthus.
Published Version
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