RRC ID 29120
Author Park KI, Hoshino A.
Title A WD40-repeat protein controls proanthocyanidin and phytomelanin pigmentation in the seed coats of the Japanese morning glory.
Journal J Plant Physiol
Abstract The protein complex composed of the transcriptional regulators containing R2R3-MYB domains, bHLH domains, and WDR in plants controls various epidermal traits, including anthocyanin and proanthocyanidin pigmentation, trichome and root hair formation, and vacuolar pH. In the Japanese morning glory (Ipomoea nil), InMYB1 having R2R3-MYB domains and InWDR1 containing WDR were shown to regulate anthocyanin pigmentation in flowers, and InWDR1 was reported to control dark-brown pigmentation and trichome formation on seed coats. Here, we report that the seed pigments of I. nil mainly comprise proanthocyanidins and phytomelanins and that these pigments are drastically reduced in the ivory seed coats of an InWDR1 mutant. In addition, a transgenic plant of the InWDR1 mutant carrying the active InWDR1 gene produced dark-brown seeds, further confirming that InWDR1 regulates seed pigmentation. Early steps in anthocyanin and proanthocyanidin biosynthetic pathways are thought to be common. In the InWDR1 mutant, none of the structural genes for anthocyanin biosynthesis that showed reduced expression in the white flowers were down-regulated in the ivory seeds, which suggests that InWDR1 may activate different sets of the structural genes for anthocyanin biosynthesis in flowers and proanthocyanidin production in seeds. As in the flowers, however, we noticed that the expression of InbHLH2 encoding a bHLH regulator was down-regulated in the seeds of the InWDR1 mutant. We discuss the implications of these results with respect to the proanthocyanidin biosynthesis in the seed coats.
Volume 169(5)
Pages 523-8
Published 2012-3-15
DOI 10.1016/j.jplph.2011.12.001
PII S0176-1617(11)00490-1
PMID 22209168
MeSH Biosynthetic Pathways Gene Expression Regulation, Plant Genes, Plant Genetic Variation Genotype Ipomoea / genetics Ipomoea / metabolism Ipomoea nil / genetics Ipomoea nil / metabolism* Melanins / biosynthesis* Melanins / genetics Microfilament Proteins / genetics Microfilament Proteins / metabolism* Pigments, Biological / biosynthesis* Pigments, Biological / genetics Plant Proteins / genetics Plant Proteins / metabolism* Plants, Genetically Modified Proanthocyanidins / biosynthesis* Proanthocyanidins / genetics Seeds / genetics Seeds / metabolism*
IF 3.013
Times Cited 9
Morning Glory AK1 AK31 AK33