A SQUAMOSA MADS box gene involved in the regulation of anthocyanin accumulation in bilberry fruits.
Anthocyanins are important health-promoting phytochemicals that are abundant in many fleshy fruits. Bilberry (Vaccinium myrtillus) is one of the best sources of these compounds. Here, we report on the expression pattern and functional analysis of a SQUAMOSA-class MADS box transcription factor, VmTDR4, associated with anthocyanin biosynthesis in bilberry. Levels of VmTDR4 expression were spatially and temporally linked with color development and anthocyanin-related gene expression. Virus-induced gene silencing was used to suppress VmTDR4 expression in bilberry, resulting in substantial reduction in anthocyanin levels in fully ripe fruits. Chalcone synthase was used as a positive control in the virus-induced gene silencing experiments. Additionally, in sectors of fruit tissue in which the expression of the VmTDR4 gene was silenced, the expression of R2R3 MYB family transcription factors related to the biosynthesis of flavonoids was also altered. We conclude that VmTDR4 plays an important role in the accumulation of anthocyanins during normal ripening in bilberry, probably through direct or indirect control of transcription factors belonging to the R2R3 MYB family.
Jaakola
Laura
L
Department of Biology University of Oulu, FIN-90014 Oulu, Finland.
Poole
Mervin
M
Jones
Matthew O
MO
Kämäräinen-Karppinen
Terttu
T
Koskimäki
Janne J
JJ
Hohtola
Anja
A
Häggman
Hely
H
Fraser
Paul D
PD
Manning
Kenneth
K
King
Graham J
GJ
Thomson
Helen
H
Seymour
Graham B
GB
D000872:Anthocyanins / Q000096:biosynthesis*; D003001:Cloning, Molecular; D005419:Flavonoids / Q000096:biosynthesis; D005638:Fruit / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D029800:Vaccinium myrtillus / Q000235:genetics / Q000378:metabolism*
D000872:Anthocyanins; D005419:Flavonoids; D026161:MADS Domain Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors