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A chalcone isomerase‐like protein enhances flavonoid production and flower pigmentation
Author(s) -
Morita Yasumasa,
Takagi Kyoko,
FukuchiMizutani Masako,
Ishiguro Kanako,
Tanaka Yoshikazu,
Nitasaka Eiji,
Nakayama Masayoshi,
Saito Norio,
Kagami Takashi,
Hoshino Atsushi,
Iida Shigeru
Publication year - 2014
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/tpj.12469
Subject(s) - chalcone isomerase , petunia , petal , flavonoid , chalcone synthase , flavonoid biosynthesis , biology , biochemistry , gene , myb , structural gene , botany , mutant , gene expression , transcriptome , antioxidant
Summary Flavonoids are major pigments in plants, and their biosynthetic pathway is one of the best‐studied metabolic pathways. Here we have identified three mutations within a gene that result in pale‐colored flowers in the Japanese morning glory ( Ipomoea nil ). As the mutations lead to a reduction of the colorless flavonoid compound flavonol as well as of anthocyanins in the flower petal, the identified gene was designated enhancer of flavonoid production ( EFP ). EFP encodes a chalcone isomerase ( CHI )‐related protein classified as a type IV CHI protein. CHI is the second committed enzyme of the flavonoid biosynthetic pathway, but type IV CHI proteins are thought to lack CHI enzymatic activity, and their functions remain unknown. The spatio‐temporal expression of EFP and structural genes encoding enzymes that produce flavonoids is very similar. Expression of both EFP and the structural genes is coordinately promoted by genes encoding R2R3‐MYB and WD 40 family proteins. The EFP gene is widely distributed in land plants, and RNA i knockdown mutants of the EFP homologs in petunia ( Petunia hybrida ) and torenia ( Torenia hybrida ) had pale‐colored flowers and low amounts of anthocyanins. The flavonol and flavone contents in the knockdown petunia and torenia flowers, respectively, were also significantly decreased, suggesting that the EFP protein contributes in early step(s) of the flavonoid biosynthetic pathway to ensure production of flavonoid compounds. From these results, we conclude that EFP is an enhancer of flavonoid production and flower pigmentation, and its function is conserved among diverse land plant species.