THE MAIZE LC REGULATORY GENE UP-REGULATES THE FLAVONOID BIOSYNTHETIC-PATHWAY OF PETUNIA

Petunia (cv. Mitchell) transformants were produced which expressed the maize Leaf colour (Lc) cDNA under the control of the CaMV 35S promote r and had enhanced pigmentation in both vegetative and floral tissues. In flowering transgenic lines, intense pigmentation of leaves, stems and sepals occurred, along with lower levels of pigmentation in the fl ower tube and limb. No anthocyanins were detected in leaves, sepals an d flower limb of wildtype Mitchell petunia. Of the 12 phenylpropanoid genes examined, transcript levels for nine flavonoid-specific biosynth etic genes were up-regulated in the transgenic Le lines, including wea k activation of CHS, CHI and F3H along with stronger activation of DFR , F3'H, F3'5'H, ANS, UFGT and 3RT. PAL, C4H and FLS were unaffected by Lc. Lc-induced pigmentation in Mitchell petunia appears to be specifi c to the sub-epidermal layer in all tissues examined, including the fl ower limb. The results show that the monocot Le regulatory gene from m aize can up-regulate the expression of both early and late flavonoid b iosynthetic genes and enhance anthocyanin production in the dicot spec ies Petunia.