An Anthocyanin Regulator from Grapes, VlmybA1-2, Produces Reddish-Purple Plants

Abstract

A cDNA, VlmybA1-2, for an anthocyanin regulatory gene of grape was constructed under the control of the cauliflower mosaic virus (CaMV) 35SRNA promoter and introduced into leaf disks and petioles of kiwifruit (Actinidia deliciosa) plants by Agrobacterium-mediated gene transfer. When the tissues were cultured on selection medium, red cells visible to the naked eye formed at the cut ends of the segments after approximately 2 weeks. The cells developed into calluses, adventitious buds, and reddish-purple plantlets after 2, 3, and 6 months of culture, respectively. The pigment produced in the leaves of the transformed plants was determined to be cyanidin 3-O-(2-O-β-xylosyl)-β-glucoside (cyanidin 3-O-sambubioside). As VlmybA1-2 can also produce red cells in tomato and eggplant, it may be useful as a visible marker to confirm efficient transformation in dicots.

DkMyb4 Is a Myb Transcription Factor Involved in Proanthocyanidin Biosynthesis in Persimmon Fruit

“…These results are presumably due to both the toxic effects of PA and disturbance by PA oxidization, because previous reports showed that phenolic compounds and their oxidation cause the browning of plant tissue and physically disturb regeneration (Madhusudhanan and Rahiman, 2000;Tang and Newton, 2004;Johkan et al, 2008). The transformation of many fruit crops, such as apple, grapevine, kiwifruit, and persimmon, depends on adventitious bud regeneration from leaves or calluses in vitro (Maheswaran et al, 1992;Matsuta et al, 1993;Scorza et al, 1995;Tao et al, 1997;Koshita et al, 2008). However, our results suggested that it is difficult to regenerate transgenic plants with DkMyb4 via adventitious buds in vitro.…”

“…Koshita et al (2008) demonstrated the effective functional analysis of grape (Vitis labruscana) Myb TF VlMYBA1-2, the regulator of anthocyanin biosynthesis, by kiwifruit transformation (Hayward). The anthocyanin and PA biosynthetic pathways share almost all structural genes except for the last catalytic steps ( Fig.…”

“…In addition, we analyzed anthocyanin accumulation with HPLC, comparing the VlMYBA1-2-introduced plants that accumulate a quantity of anthocyanin (Koshita et al, 2008) and the DkMyb4-introduced plants. The major anthocyanin of VlMYBA1-2-introduced plants was detected as cyanidin 3-O-(2-O-b-xylosyl)-b-glucoside, as reported by Koshita et al (2008). On the other hand, no anthocyanins were detected in DkMyb4-introduced plants (Supplemental Fig.…”

“…Anthocyanins in kiwifruit (Actinidia deliciosa) plants were extracted with 5% aqueous acetic acid. We analyzed anthocyanin content according to the previous report by Koshita et al (2008) with some modifications. Samples were run on a reverse-phase HPLC apparatus (LC2010) using a Shim-pack VP-ODS analytical column (4.6 mm 3 150 mm; Shimadzu) at 40°C with a flow rate of 1 mL min 21 by detecting A 240-580 .…”

Regulation of Anthocyanin Biosynthesis in Grapes

“…This indicates that UFGT is a key enzyme and that VlmybA genes induce anthocyanin biosynthesis in grape via expression of UFGT. Interestingly, VlmybA1-2 can also induce red cells in tissues of kiwifruit, tomato, and eggplant (Koshita et al, 2008).…”