TY - JOUR
T1 - Cloning and molecular analysis of HlbZip1 and HlbZip2 transcription factors putatively involved in the regulation of the lupulin metabolome in Hop (Humulus lupulus L.)
AU - Matousek, Jaroslav
AU - Kocabek, Tomas
AU - Patzak, Josef
AU - Stehlik, Jan
AU - Fuessy, Zoltan
AU - Krofta, Karel
AU - Heyerick, Arne
AU - Roldan-Ruiz, Isabel
AU - Maloukh, Lina
AU - De Keukeleire, Denis
PY - 2010
Y1 - 2010
N2 - Hop (Humulus lupulus L.), the essential source of beer flavor is of interest from a medicinal perspective in view of its high content in health-beneficial terpenophenolics including prenylflavonoids. The dissection of biosynthetic pathway(s) of these compounds in lupulin glands, as well as its regulation by transcription factors (TFs), is important for efficient biotech no logical manipulation of the hop metabolome. TFs of the bZIP class were preselected from the hop transcriptome using a cDNA-AFLP approach and cloned from a cDNA library based on glandular tissue-enriched hop cones. The cloned TFs HlbZIP1A and HlbZIP2 have predicted molecular masses of 27.4 and 34.2 kDa, respectively, and both are similar to the group A3 bZIP TFs according to the composition of characteristic domains. While HlbZIP1A is rather neutral (pl 6.42), HlbZIP2 is strongly basic (pl 8,51). A truncated variant of HlbZIP1 (HlbZIP1B), which is strongly basic but lacks the leucine zipper domain, has also been cloned from hop. Similar to the previously cloned HIMyb3 from hop, both bZIP TFs show a highly specific expression in lupulin glands, although low expression was observed also in other tissues including roots and immature pollen. Comparative functional analyses of HbZip1A, HlbZip2, and subvariants of HIMyb3 were performed in a transient expression system using Nicotiana benthamiana leaf coinfiltration with Agrobacterium tumefaciens strains bearing hop TFs and selected promoters fused to the GUS reference gene. both hop bZIP TFs and HIMyb3 mainly activated the promoters of chalcone synthase chsH1 and the,newly cloned O-methyl transferase 1 genes, while the response of the valerophenone synthase promoter to the cloned hop TFs was very low. These analyses also showed that the cloned bZIP TFs are not strictly G-box-specific. HPLC analysis of secondary metabolites in infiltrated Petunia hybrida showed that both hop bZIP TFs interfere with the accumulation and the composition of flavonol glycosides, phenolic acids, and anthocyanins, suggesting the possibility of coregulating flavonoid biosynthetic pathways in hop glandular tissue.
AB - Hop (Humulus lupulus L.), the essential source of beer flavor is of interest from a medicinal perspective in view of its high content in health-beneficial terpenophenolics including prenylflavonoids. The dissection of biosynthetic pathway(s) of these compounds in lupulin glands, as well as its regulation by transcription factors (TFs), is important for efficient biotech no logical manipulation of the hop metabolome. TFs of the bZIP class were preselected from the hop transcriptome using a cDNA-AFLP approach and cloned from a cDNA library based on glandular tissue-enriched hop cones. The cloned TFs HlbZIP1A and HlbZIP2 have predicted molecular masses of 27.4 and 34.2 kDa, respectively, and both are similar to the group A3 bZIP TFs according to the composition of characteristic domains. While HlbZIP1A is rather neutral (pl 6.42), HlbZIP2 is strongly basic (pl 8,51). A truncated variant of HlbZIP1 (HlbZIP1B), which is strongly basic but lacks the leucine zipper domain, has also been cloned from hop. Similar to the previously cloned HIMyb3 from hop, both bZIP TFs show a highly specific expression in lupulin glands, although low expression was observed also in other tissues including roots and immature pollen. Comparative functional analyses of HbZip1A, HlbZip2, and subvariants of HIMyb3 were performed in a transient expression system using Nicotiana benthamiana leaf coinfiltration with Agrobacterium tumefaciens strains bearing hop TFs and selected promoters fused to the GUS reference gene. both hop bZIP TFs and HIMyb3 mainly activated the promoters of chalcone synthase chsH1 and the,newly cloned O-methyl transferase 1 genes, while the response of the valerophenone synthase promoter to the cloned hop TFs was very low. These analyses also showed that the cloned bZIP TFs are not strictly G-box-specific. HPLC analysis of secondary metabolites in infiltrated Petunia hybrida showed that both hop bZIP TFs interfere with the accumulation and the composition of flavonol glycosides, phenolic acids, and anthocyanins, suggesting the possibility of coregulating flavonoid biosynthetic pathways in hop glandular tissue.
U2 - 10.1021/jf9043106
DO - 10.1021/jf9043106
M3 - A1: Web of Science-article
SN - 0021-8561
VL - 58
SP - 902
EP - 912
JO - Journal of Agricultural and Food Chemistry
JF - Journal of Agricultural and Food Chemistry
IS - 2
ER -