Identification of full-length cDNA sequences of hop (Humulus lupulus L.) candidate genes of the prenylflavonid pathway

A noticeable shift of interest for hop (Humulus lupulus L.) is ongoing from flavour-active beer constituents to health-beneficial properties of prenylchalcones, mainly desmethylxanthohumol and xanthohumol. Desmethylxanthohumol serves as a pro-estrogen, since it is readily isomerized to 8-prenylnaringenin, the most potent phytoestrogen currently known, while xanthohumol shows an exceptionally broad spectrum of inhibition mechanisms at all stages of carcinogenesis. However, the low availability of the target compounds in hop glandular trichomes prevents the widespread exploitation of the biological properties of these two compounds. A detailed characterization of genes and regulatory elements in the phenylpropanoid pathway leading to prenylchalcones should contribute to a better understanding of the synthesis of bioactive components in hop. Two hop genes displaying similarities to genes of the prenylpropanoid pathway and one transcription factor were identified by combining a cDNA-AFLP screen of hop cones, cDNA-library screening and Rapid Amplification of cDNA Ends (RACE) approaches. In order to carry out a functional analysis of these genes, gene-transfer experiments are currently being carried out using an Agrobacterium-mediated protocol