| Abstract
| - The concentrations of prenylated chalcones and bitter acids were analyzed in Czech hop varieties.The highest levels of (xanthohumol + desmethylxanthohumol) (0.97%, m/m) and of total bitter acids(17.19%, m/m) were observed for cv. Agnus. The concentration ratios of bitter acids to prenylatedchalcones varied depending on the genotype, thereby suggesting genetic determination by differentset(s) of structural and regulatory genes. Promoter elements of the chs_H1 gene encoding a “true”chalcone synthase, a candidate gene to co-determine the biosynthesis of prenylated chalcones, wereanalyzed, and several boxes for cis-regulatory elements including Myb transcription factors werediscovered. A cDNA library was established from glandular tissue-enriched cones of cv. Osvald'sclone 72 and used to screen for Myb regulatory elements. The cDNA of the first Myb regulatoryfactor from hop, called HlMyb1, was cloned and analyzed. The HlMyb1 open reading frame encodes272 amino acids (29.8 kDa), and the protein showed highest homology to the light-regulated factorAtMyb68 from Arabidopsis thaliana within the Myb domain, whereas there was no significant homologywith known MYB proteins outside this domain. Unlike AtMyb68, which is expressed in mature leaves,HlMyb1 is strongly expressed in hop inflorescences and could participate in the regulation ofdevelopmental processes involved in the production of hop cones and bioactive secondary metabolites. Keywords: Hop; prenylated flavonoids; transcription factors; hop cDNA library; biosynthesis
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