Cloning and molecular analysis of the regulatory factor HlMyb1 in hop (Humulus lupulus L.) and the potential of hop to produce bioactive prenylated flavonoids.
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.
Matousek
Jaroslav
J
Institute of Plant Molecular Biology AS CR, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
Vrba
Lukás
L
Novák
Petr
P
Patzak
Josef
J
De Keukeleire
Jelle
J
Skopek
Josef
J
Heyerick
Arne
A
Roldán-Ruiz
Isabel
I
De Keukeleire
Denis
D
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
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