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The Rc and Rd genes are involved in proanthocyanidin synthesis in rice pericarp
Author(s) -
Furukawa Tsutomu,
Maekawa Masahiko,
Oki Tomoyuki,
Suda Ikuo,
Iida Shigeru,
Shimada Hiroaki,
Takamure Itsuro,
Kadowaki Kohichi
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.02958.x
Subject(s) - locus (genetics) , gene , biology , mutant , genetically modified rice , genetics , red rice , rice protein , brown rice , oryza sativa , candidate gene , proanthocyanidin , transgene , genetically modified crops , biochemistry , horticulture , food science , polyphenol , antioxidant
Summary Different colors, such as purple, brown, red and white, occur in the pericarp of rice. Here, two genes affecting proanthocyanidin synthesis in red‐ and brown‐colored rice were elucidated. Genetic segregation analysis suggested that the Rd and A loci are identical, and both encode dihydroflavonol‐4‐reductase (DFR). The introduction of the DFR gene into an Rcrd mutant resulted in red‐colored rice, which was brown in the original mutant, demonstrating that the Rd locus encodes the DFR protein. Accumulation of proanthocyanidins was observed in the transformants by the introduction of the Rd gene into the rice Rcrd line. Protein blot analysis showed that the DFR gene was translated in seeds with alternative translation initiation. A search for the Rc gene, which encodes a transacting regulatory factor, was conducted using available DNA markers and the Rice Genome Automated Annotation System program. Three candidate genes were identified and cloned from a rice RcRd line and subsequently introduced into a rice rcrd line. Brown‐colored seeds were obtained from transgenic plants by the introduction of a gene containing the basic helix–loop–helix (bHLH) motif, demonstrating that the Rc gene encodes a bHLH protein. Comparison of the Rc locus among rice accessions showed that a 14‐bp deletion occurred only in the rc locus.