8th INTERNATIONAL WHEAT CONFERENCE

fLAVoNoId BIoSyNTheSIS geNeS IN WheAT: geNome
LoCATIoN ANd fuNCTIoN
Khlestkina E.K. 1, Tereshchenko O.Y. 1, Pshenichnikova T.A. 1 ,
Arbuzova V.S. 1 , Röder M.S. 2 , Börner A. 2 , Salina E.A. 1
1 Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences,
Novosibirsk, 630090, Russia
2 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, D-06466
Gatersleben, Germany
E-mail Address of presenting author: khlest@bionet.nsc.ru
The flavonoid biosynthesis pathway (FBP) is central to the formation of the phenolic
compounds which serve essential functions in plant defense, reproduction, etc. Flavonoids
are also known for their antioxidant activity and medicinal properties. In some
cases, accumulation of flavonoids may become visible because of their derived pigments
(e.g. anthocyanins, proanthocyanidins, 3-deoxyanthocyanidins). The genes which underlie
the anthocyanin pigmentation of the coleoptile (Rc), culm (Pc), anther (Pan), auricle
(Ra) and pericarp (Pp) have been known in wheat. In the current study, we describe
novel genes controlling anthocyanin pigmentation of the glume (Pg), leaf blade (Plb) and
leaf sheath (Pls). Comparative molecular-genetic mapping of the anthocyanin pigmentation
genes showed Pg to be closely linked to the Pp gene on chromosome 2A, whereas Rc,
Pc, Pan, Plb and Pls form homoeologous clusters on chromosomes 7AS (Rc-A1, Pc-A1,
Pls-A1, Plb-A1, Pan-A1), 7BS (Rc-B1, Pc-B1, Pls-B1, Plb-B1) and 7DS (Rc-D1, Pc-D1, Pls-
D1, Plb-D1, Pan-D1), respectively. Unlike the gene controlling purple glume color (Pg),
the genes Bg (determining black glume color), Rg1, Rg2 and Rg3 (red glume), and a locus
determining smokey-grey colored glume are located on the chromosomes of homoeologous
group 1. In the current study, these genes were genetically mapped to the distal ends
of chromosomes 1AS, 1BS and 1DS, proximally (or closely linked) to microsatellite locus
Xgwm1223 and distal to Xgwm0033. On this basis, we propose that these genes represent
a set of homoeoloci, designated Rg-A1, Rg-B1 and Rg-D1. Rg3 and Bg appear to be variant
alleles of Rg-A1. Similarly, the smokey-grey glume gene and Rg2 represent alleles at
Rg-D1. The nature of these red, black and smokey-grey pigments in wheat glumes has not
been studied thus far. None of the genes determining pigmentation in wheat has been
cloned and sequenced yet. However, similar to well-studied morphological pigmentation
genes in maize, these genes in wheat can be supposed to be tissue-specific transcription
activators of the genes encoding FBP enzymes. In order to investigate how the different
alleles of the morphological genes affect transcription activity of wheat FBP structural
genes, we cloned nucleotide sequences of the two key FBP enzymes chalcone-flavanone
isomerase (CHI) and flavanone 3-hydroxylase (F3H). More than one copy of each of
the two genes were isolated from bread wheat. To distinguish between homoeologous/
paralogous copies, gene copy-specific primers were designed on the basis of DNA-polymorphism
and used for mapping. Thus, two homoeologous copies of the CHI gene were
isolated and mapped to chromosomes 5BL and 5DL. Four copies of the F3H gene we
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