Kvasny Prum. 2012; 58(1): 13-19 | DOI: 10.18832/kp2012003

"Transgenic" metabolome of hop, some aspects of its development and prospects of utilization.Peer-reviewed article

Jaroslav MATOUŠEK

Biologické centrum AV ČR v.v.i., Ústav molekulární biologie rostlin, Oddělení molekulární genetiky, Branišovská 31, 370 05 České Budějovice

Hop, which is mainly cultivated for the brewing industry, as a source of flavor-active secondary metabolites providing desired bitterness and aroma to beer, produces the metabolome containing compounds beneficial for human health. These are mainly prenylflavonoids as Xanthohumol, with anticancerogenic, antiangiogenic and estrogenic activities. It is the recent effort of breeders to gain new hop cultivars with higher level of Xanthohumol. It is expected that the level of these compounds which reaches just 1-2% in the best breeding materials, could be enhanced in "transgenic metabolome" introduced by the biotechnology with the use of newly identified lupulin-specific genes and transcription factors (TF) from Myb, bZip, WD40 and bHLH families that participate in their regulations. At present, we found complex character of regulation of prenylflavonoid bio-synthetic pathway including an involvement of so-called ternary and binary TF complexes, positive regulators, as well as transcription suppressor. This knowledge enables targeted hop transformation for the preparation of transgenic metabolome and makes realistic the perspective to induce metabolically active transgenic tissue cultures of hop. An effective usefulness of transgenic metabolome of hop will depend on their findings of basic research in the metabolic pathways of lupulin and social awareness with a new practical benefit of GMO, that will include successively not only production of polyphenols, but also bitter acids and aromatic compounds.Hop, which is mainly cultivated for the brewing industry, as a source of flavor-active secondary metabolites providing desired bitterness and aroma to beer, produces the metabolome containing compounds beneficial for human health. These are mainly prenylflavonoids as Xanthohumol, with anticancerogenic, antiangiogenic and estrogenic activities. It is the recent effort of breeders to gain new hop cultivars with higher level of Xanthohumol. It is expected that the level of these compounds which reaches just 1-2% in the best breeding materials, could be enhanced in "transgenic metabolome" introduced by the biotechnology with the use of newly identified lupulin-specific genes and transcription factors (TF) from Myb, bZip, WD40 and bHLH families that participate in their regulations. At present, we found complex character of regulation of prenylflavonoid bio-synthetic pathway including an involvement of so-called ternary and binary TF complexes, positive regulators, as well as transcription suppressor. This knowledge enables targeted hop transformation for the preparation of transgenic metabolome and makes realistic the perspective to induce metabolically active transgenic tissue cultures of hop. An effective usefulness of transgenic metabolome of hop will depend on their findings of basic research in the metabolic pathways of lupulin and social awareness with a new practical benefit of GMO, that will include successively not only production of polyphenols, but also bitter acids and aromatic compounds.

Keywords: Czech hop, lupulin, regulatory factors, transgenosis, anticancerogenic compounds, biotechnology

Received: August 16, 2011; Accepted: October 3, 2011; Published: January 1, 2012