title: Cloning and molecular analysis of the regulatory factor HlMyb1 in hop (Humulus lupulus L.) and the potential of hop to produce bioactive prenylated flavonoids.
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 prenylated chalcones varied depending on the genotype, thereby suggesting genetic determination by different set(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, were analyzed, and several boxes for cis-regulatory elements including Myb transcription factors were discovered. A cDNA library was established from glandular tissue-enriched cones of cv. Osvald's clone 72 and used to screen for Myb regulatory elements. The cDNA of the first Myb regulatory factor from hop, called HlMyb1, was cloned and analyzed. The HlMyb1 open reading frame encodes 272 amino acids (29.8 kDa), and the protein showed highest homology to the light-regulated factor AtMyb68 from Arabidopsis thaliana within the Myb domain, whereas there was no significant homology with 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 of developmental processes involved in the production of hop cones and bioactive secondary metabolites.
authors.affiliation: Institute of Plant Molecular Biology AS CR, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Matousek
authors.forename: Lukás
authors.initials: L
authors.lastname: Vrba
authors.forename: Petr
authors.initials: P
authors.lastname: Novák
authors.forename: Josef
authors.initials: J
authors.lastname: Patzak
authors.forename: Jelle
authors.initials: J
authors.lastname: De Keukeleire
authors.forename: Josef
authors.initials: J
authors.lastname: Skopek
authors.forename: Arne
authors.initials: A
authors.lastname: Heyerick
authors.forename: Isabel
authors.initials: I
authors.lastname: Roldán-Ruiz
authors.forename: Denis
authors.initials: D
authors.lastname: De Keukeleire
mesh_terms: D000217:Acyltransferases / Q000737:chemistry* / Q000235:genetics*; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins; D001483:Base Sequence; D047188:Chalcones / Q000032:analysis; D003001:Cloning, Molecular; D027582:Humulus / Q000737:chemistry* / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D017368:Protein Prenylation; D020598:Proto-Oncogene Proteins c-myb / Q000737:chemistry* / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment
chemical_list: C511988:ATR1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C511989:CPC protein, Arabidopsis; D047188:Chalcones; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger; D000217:Acyltransferases; C020141:flavanone synthetase