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De Keukeleire J, Ooms G, Heyerick A, Roldan-Ruiz I, Van Bockstaele E, De Keukeleire D. Formation and accumulation of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol during flowering of hops (Humulus lupulus L.). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:4436-41. [PMID: 12848522 DOI: 10.1021/jf034263z] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Important secondary metabolites, present in hops (Humulus lupulus L.), include alpha-acids and beta-acids, which are essential for the brewing of beer, as well as the prenylated chalcones, desmethylxanthohumol, and xanthohumol, which exhibit interesting bioactive properties. Their formation and accumulation in five selected hop varieties, Wye Challenger, Wye Target, Golding, Admiral, and Whitbread Golding Variety, were quantitatively monitored by high-performance liquid chromatography using UV detection. All target compounds were present from the onset of flowering, not only in female hop cones but also in male inflorescences, albeit in low concentrations. During development from female inflorescences to cones, levels of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol gradually increased, while each hop variety exhibited individual accumulation rates. Furthermore, these compounds were present in leaves of fully grown hops as well. The study demonstrated that key compounds for flavor and potential beneficial health effects associated with beer not only reside in the glandular lupulin structures but also are distributed over various parts of the hop plant.
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Kishimoto T, Kobayashi M, Yako N, Iida A, Wanikawa A. Comparison of 4-Mercapto-4-methylpentan-2-one contents in hop cultivars from different growing regions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:1051-7. [PMID: 18173243 DOI: 10.1021/jf072173e] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Contributions of hop-derived thiols were examined. Extremely strong fruity, black currant-like aromas were detected in beers hopped with some U.S. cultivars. 4-Mercapto-4-methylpentan-2-one (4MMP) was supposed to be the main contributor to the fruity aroma, and the contents between cultivars were investigated. In hop pellets, a negative correlation between 4MMP concentration and copper ion content in hops was observed. 4MMP was detected only in U.S., Australian, and New Zealand cultivars, but no European ones, which are treated with copper-containing fungicides (Bordeaux mixture) and therefore have a high content of copper ions. The 4MMP content was highest in Simcoe cultivars, followed by Summit, Apollo, Topaz, Cascade pellets, and also differed between crop years. It was indicated that most 4MMP exists freely in wort or in hop pellets with only small amounts formed from precursors and that the amounts increased during the fermentation process.
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Comparative Study |
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Harish V, Haque E, Śmiech M, Taniguchi H, Jamieson S, Tewari D, Bishayee A. Xanthohumol for Human Malignancies: Chemistry, Pharmacokinetics and Molecular Targets. Int J Mol Sci 2021; 22:ijms22094478. [PMID: 33923053 PMCID: PMC8123270 DOI: 10.3390/ijms22094478] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 12/15/2022] Open
Abstract
Xanthohumol (XH) is an important prenylated flavonoid that is found within the inflorescence of Humulus lupulus L. (Hop plant). XH is an important ingredient in beer and is considered a significant bioactive agent due to its diverse medicinal applications, which include anti-inflammatory, antimicrobial, antioxidant, immunomodulatory, antiviral, antifungal, antigenotoxic, antiangiogenic, and antimalarial effects as well as strong anticancer activity towards various types of cancer cells. XH acts as a wide ranging chemopreventive and anticancer agent, and its isomer, 8-prenylnaringenin, is a phytoestrogen with strong estrogenic activity. The present review focuses on the bioactivity of XH on various types of cancers and its pharmacokinetics. In this paper, we first highlight, in brief, the history and use of hops and then the chemistry and structure–activity relationship of XH. Lastly, we focus on its prominent effects and mechanisms of action on various cancers and its possible use in cancer prevention and treatment. Considering the limited number of available reviews on this subject, our goal is to provide a complete and detailed understanding of the anticancer effects of XH against different cancers.
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Review |
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Xu H, Zhang F, Liu B, Huhman DV, Sumner LW, Dixon RA, Wang G. Characterization of the formation of branched short-chain fatty acid:CoAs for bitter acid biosynthesis in hop glandular trichomes. MOLECULAR PLANT 2013; 6:1301-17. [PMID: 23300257 DOI: 10.1093/mp/sst004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop (Humulus lupulus) glandular trichomes. Branched short-chain acyl-CoAs (e.g. isobutyryl-CoA, isovaleryl-CoA and 2-methylbutyryl-CoA), derived from the degradation of branched-chain amino acids (BCAAs), are essential building blocks for the biosynthesis of bitter acids in hops. However, little is known regarding what components are needed to produce and maintain the pool of branched short-chain acyl-CoAs in hop trichomes. Here, we present several lines of evidence that both CoA ligases and thioesterases are likely involved in bitter acid biosynthesis. Recombinant HlCCL2 (carboxyl CoA ligase) protein had high specific activity for isovaleric acid as a substrate (K cat /K m = 4100 s(-1) M(-1)), whereas recombinant HlCCL4 specifically utilized isobutyric acid (Kcat/K m = 1800 s(-1) M(-1)) and 2-methylbutyric acid (Kcat/K m = 6900 s(-1) M(-1)) as substrates. Both HlCCLs, like hop valerophenone synthase (HlVPS), were expressed strongly in glandular trichomes and localized to the cytoplasm. Co-expression of HlCCL2 and HlCCL4 with HlVPS in yeast led to significant production of acylphloroglucinols (the direct precursors for bitter acid biosynthesis), which further confirmed the biochemical function of these two HlCCLs in vivo. Functional identification of a thioesterase that catalyzed the reverse reaction of CCLs in mitochondria, together with the comprehensive analysis of genes involved BCAA catabolism, supported the idea that cytosolic CoA ligases are required for linking BCAA degradation and bitter acid biosynthesis in glandular trichomes. The evolution and other possible physiological roles of branched short-chain fatty acid:CoA ligases in planta are also discussed.
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Kawaguchi-Ito Y, Li SF, Tagawa M, Araki H, Goshono M, Yamamoto S, Tanaka M, Narita M, Tanaka K, Liu SX, Shikata E, Sano T. Cultivated grapevines represent a symptomless reservoir for the transmission of hop stunt viroid to hop crops: 15 years of evolutionary analysis. PLoS One 2009; 4:e8386. [PMID: 20041179 PMCID: PMC2793511 DOI: 10.1371/journal.pone.0008386] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 11/19/2009] [Indexed: 11/22/2022] Open
Abstract
Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics.
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Reglitz K, Steinhaus M. Quantitation of 4-Methyl-4-sulfanylpentan-2-one (4MSP) in Hops by a Stable Isotope Dilution Assay in Combination with GC×GC-TOFMS: Method Development and Application To Study the Influence of Variety, Provenance, Harvest Year, and Processing on 4MSP Concentrations. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:2364-2372. [PMID: 28245644 DOI: 10.1021/acs.jafc.7b00455] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A stable isotope dilution assay was developed for quantitation of 4-methyl-4-sulfanylpentan-2-one (4MSP) in hops. The approach included the use of 4-(13C)methyl-4-sulfanyl(1,3,5-13C3)pentan-2-one as internal standard, selective isolation of hop thiols by mercurated agarose, and GC×GC-TOFMS analysis. Application of the method to 53 different hop samples revealed 4MSP concentrations between <1 and 114 μg/kg. Notably high concentrations were associated with United States varieties such as Citra, Eureka, Simcoe, and Apollo, whereas 4MSP was absent from traditional German and English varieties. Further experiments showed that besides the variety, also harvest year and storage vitally influenced 4MSP concentrations, whereas the impact of provenance was less pronounced. Hop processing such as drying and pelletizing had only a minor impact on 4MSP concentrations. Like the majority of other hop volatiles, 4MSP is predominantly located in the lupulin glands.
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Evaluation Study |
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Kavalier AR, Litt A, Ma C, Pitra NJ, Coles MC, Kennelly EJ, Matthews PD. Phytochemical and morphological characterization of hop (Humulus lupulus L.) cones over five developmental stages using high performance liquid chromatography coupled to time-of-flight mass spectrometry, ultrahigh performance liquid chromatography photodiode array detection, and light microscopy techniques. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:4783-93. [PMID: 21456557 DOI: 10.1021/jf1049084] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Hop (Humulus lupulus L.) inflorescences, commonly known as "hop cones", are prized for their terpenophenolic contents, used in beer production and, more recently, in biomedical applications. In this study we investigated morphological and phytochemical characteristics of hop cones over five developmental stages, using liquid chromatography coupled to time-of-flight mass spectrometry (LC-TOF-MS), and ultrahigh performance liquid chromatography photodiode array detection (UHPLC-PDA) methods to quantitate 21 polyphenolics and seven terpenophenolics. Additionally, we used light microscopy to correlate phytochemical quantities with changes in the morphology of the cones. Significant increases in terpenophenolics, concomitant with glandular trichome development and associated gross morphological changes, were mapped over development to fluctuations in contents of polyphenolic constituents and their metabolic precursor compounds. The methods reported here can be used for targeted metabolic profiling of flavonoids, phenolic acids, and terpenophenolics in hops, and are applicable to quantitation in other crops.
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Evaluation Study |
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McAdam EL, Freeman JS, Whittock SP, Buck EJ, Jakse J, Cerenak A, Javornik B, Kilian A, Wang CH, Andersen D, Vaillancourt RE, Carling J, Beatson R, Graham L, Graham D, Darby P, Koutoulis A. Quantitative trait loci in hop (Humulus lupulus L.) reveal complex genetic architecture underlying variation in sex, yield and cone chemistry. BMC Genomics 2013; 14:360. [PMID: 23718194 PMCID: PMC3680207 DOI: 10.1186/1471-2164-14-360] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/23/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hop (Humulus lupulus L.) is cultivated for its cones, the secondary metabolites of which contribute bitterness, flavour and aroma to beer. Molecular breeding methods, such as marker assisted selection (MAS), have great potential for improving the efficiency of hop breeding. The success of MAS is reliant on the identification of reliable marker-trait associations. This study used quantitative trait loci (QTL) analysis to identify marker-trait associations for hop, focusing on traits related to expediting plant sex identification, increasing yield capacity and improving bittering, flavour and aroma chemistry. RESULTS QTL analysis was performed on two new linkage maps incorporating transferable Diversity Arrays Technology (DArT) markers. Sixty-three QTL were identified, influencing 36 of the 50 traits examined. A putative sex-linked marker was validated in a different pedigree, confirming the potential of this marker as a screening tool in hop breeding programs. An ontogenetically stable QTL was identified for the yield trait dry cone weight; and a QTL was identified for essential oil content, which verified the genetic basis for variation in secondary metabolite accumulation in hop cones. A total of 60 QTL were identified for 33 secondary metabolite traits. Of these, 51 were pleiotropic/linked, affecting a substantial number of secondary metabolites; nine were specific to individual secondary metabolites. CONCLUSIONS Pleiotropy and linkage, found for the first time to influence multiple hop secondary metabolites, have important implications for molecular selection methods. The selection of particular secondary metabolite profiles using pleiotropic/linked QTL will be challenging because of the difficulty of selecting for specific traits without adversely changing others. QTL specific to individual secondary metabolites, however, offer unequalled value to selection programs. In addition to their potential for selection, the QTL identified in this study advance our understanding of the genetic control of traits of current economic and breeding significance in hop and demonstrate the complex genetic architecture underlying variation in these traits. The linkage information obtained in this study, based on transferable markers, can be used to facilitate the validation of QTL, crucial to the success of MAS.
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Keukeleire JD, Janssens I, Heyerick A, Ghekiere G, Cambie J, Roldan-Ruiz I, Bockstaele EV, Keukeleire DD. Relevance of organic farming and effect of climatological conditions on the formation of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol in hop (Humulus lupulus L.). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:61-6. [PMID: 17199314 DOI: 10.1021/jf061647r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The concentrations of alpha-acids, beta-acids, desmethylxanthohumol, and xanthohumol were monitored in the hop varieties Admiral (A), Wye Challenger (WC), and First Gold (FG) during the harvest seasons of 2003 through 2005. Hops grown under an organic regimen were compared to plants grown conventionally in hop fields in close vicinity. The concentrations of the key compounds depended very much on climatological conditions showing, in general, highest levels in poorest weather conditions (2004). Of the three varieties studied, FG was the only one showing a clear trend for higher concentrations of secondary metabolites under organic growing conditions than under conventional farming conditions. Cultivation of A and WC seems to be very sensitive to climatic conditions and environmental stresses caused by pests and diseases, thereby leading to various results. WC proved to be a rich source of bioactive chalcones, particularly desmethylxanthohumol.
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Rodolfi M, Chiancone B, Liberatore CM, Fabbri A, Cirlini M, Ganino T. Changes in chemical profile of Cascade hop cones according to the growing area. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:6011-6019. [PMID: 31216060 DOI: 10.1002/jsfa.9876] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/29/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The growing area has a substantial effect on plants, affecting secondary metabolism. For hops, different authors have studied the effect of growing area on the chemical composition of cones with the aim of verifying and understanding the changes in hop characters. Despite the scant literature the subject receives increasing attention by brewers and hop growers. The present study aimed to characterize, using gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography with ultraviolet detection (HPLC-UV), cones of hop (Humulus lupulus L.) cultivar Cascade. Plant material was obtained from nine different areas of Italy and compared with Cascade samples grown in the United States, Germany and Slovenia. RESULTS Differences in bitter acids and xanthohumol content were observed. Nevertheless, no correlation between bitter acids and xanthohumol production, on the one hand, and rainfall, temperatures and latitude, on the other hand, were observed in our samples. The Slovenia samples were richer in molecules that confer hoppy, woody and flower notes; USA2 samples were more characterized by woody, earthy, grassy and floral aroma, quite different characters if compared to USA1, which had the lowest presence of grassy aromatic compounds. In the Italian samples, TRENTINO was the genotype most characterized by limonene presence. CONCLUSION The results of this study are indicative of the importance for hop users to know and characterize hops coming from different growing regions. The study pays special attention to the characterization of the differences in chemical characters of Cascade hop in Italy, where hop cultivation has developed only recently, but is in continuous expansion. © 2019 Society of Chemical Industry.
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Fortes AM, Santos F, Choi YH, Silva MS, Figueiredo A, Sousa L, Pessoa F, Santos BA, Sebastiana M, Palme K, Malhó R, Verpoorte R, Pais MS. Organogenic nodule development in hop (Humulus lupulus L.): transcript and metabolic responses. BMC Genomics 2008; 9:445. [PMID: 18823540 PMCID: PMC2573896 DOI: 10.1186/1471-2164-9-445] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 09/29/2008] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Hop (Humulus lupulus L.) is an economically important plant forming organogenic nodules which can be used for genetic transformation and micropropagation. We are interested in the mechanisms underlying reprogramming of cells through stress and hormone treatments. RESULTS An integrated molecular and metabolomic approach was used to investigate global gene expression and metabolic responses during development of hop's organogenic nodules. Transcript profiling using a 3,324-cDNA clone array revealed differential regulation of 133 unigenes, classified into 11 functional categories. Several pathways seem to be determinant in organogenic nodule formation, namely defense and stress response, sugar and lipid metabolism, synthesis of secondary metabolites and hormone signaling. Metabolic profiling using 1H NMR spectroscopy associated to two-dimensional techniques showed the importance of metabolites related to oxidative stress response, lipid and sugar metabolism and secondary metabolism in organogenic nodule formation. CONCLUSION The expression profile of genes pivotal for energy metabolism, together with metabolites profile, suggested that these morphogenic structures gain energy through a heterotrophic, transport-dependent and sugar-degrading anaerobic metabolism. Polyamines and auxins are likely to be involved in the regulation of expression of many genes related to organogenic nodule formation. These results represent substantial progress toward a better understanding of this complex developmental program and reveal novel information regarding morphogenesis in plants.
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McAdam EL, Vaillancourt RE, Koutoulis A, Whittock SP. Quantitative genetic parameters for yield, plant growth and cone chemical traits in hop (Humulus lupulus L.). BMC Genet 2014; 15:22. [PMID: 24524684 PMCID: PMC3927220 DOI: 10.1186/1471-2156-15-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 02/11/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Most traits targeted in the genetic improvement of hop are quantitative in nature. Improvement based on selection of these traits requires a comprehensive understanding of their inheritance. This study estimated quantitative genetic parameters for 20 traits related to three key objectives for the genetic improvement of hop: cone chemistry, cone yield and agronomic characteristics. RESULTS Significant heritable genetic variation was identified for α-acid and β-acid, as well as their components and relative proportions. Estimates of narrow-sense heritability for these traits (h2 = 0.15 to 0.29) were lower than those reported in previous hop studies, but were based on a broader suite of families (108 from European, North American and hybrid origins). Narrow-sense heritabilities are reported for hop growth traits for the first time (h2 = 0.04 to 0.20), relating to important agronomic characteristics such as emergence, height and lateral morphology. Cone chemistry and growth traits were significantly genetically correlated, such that families with more vigorous vegetative growth were associated with lower α-acid and β-acid levels. This trend may reflect the underlying population structure of founder genotypes (European and North American origins) as well as past selection in the Australian environment. Although male and female hop plants are thought to be indistinguishable until flowering, sex was found to influence variation in many growth traits, with male and female plants displaying differences in vegetative morphology from emergence to cone maturity. CONCLUSIONS This study reveals important insights into the genetic control of quantitative hop traits. The information gained will provide hop breeders with a greater understanding of the additive genetic factors which affect selection of cone chemistry, yield and agronomic characteristics in hop, aiding in the future development of improved cultivars.
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Fortes AM, Coronado MJ, Testillano PS, Risueño MDC, Pais MS. Expression of Lipoxygenase During Organogenic Nodule Formation from Hop Internodes. J Histochem Cytochem 2016; 52:227-41. [PMID: 14729875 DOI: 10.1177/002215540405200211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Study of lipoxygenase expression (LOX; EC 1.13.11.12) during organogenic nodule formation in hop ( Humulus lupulus var. Nugget) showed that LOXs are developmentally regulated throughout the process, suggesting their involvement in the response of internodes to wounding, nodule formation, and plantlet regeneration from these nodules. LOX activity and lipid peroxides exhibited a huge increase during the first week of culture, which may indicate a role for LOX and LOX products in response to wounding in hop, as reported for other systems. Western blotting analysis showed a de novo synthesis of LOX isoenzymes in response to wounding and the detection of three different isoenzymes. Confocal analysis of LOX immunofluorescence revealed the presence of the enzyme in cortical cells of induced internodes and in prenodular cells, mostly appearing as cytoplasmic spots. Some of them were identified as lipid bodies by cytochemical and double immunofluorescence assays, suggesting the involvement of a lipid body LOX during nodule formation. Immunogold labeling detected LOX in peroxisomes, lipid bodies, and plastids of nodular cells. Quantification of the labeling density provided statistical significance for the localization of LOX (three different isoenzymes) in the three compartments, which suggested a possible involvement of LOX in metabolic functions of these organelles during organogenic nodule formation and plantlet regeneration.
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Peredo EL, Arroyo-García R, Revilla MA. Epigenetic changes detected in micropropagated hop plants. JOURNAL OF PLANT PHYSIOLOGY 2009; 166:1101-11. [PMID: 19285752 DOI: 10.1016/j.jplph.2008.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 11/26/2008] [Accepted: 12/19/2008] [Indexed: 05/08/2023]
Abstract
Micropropagation is a widely used technique in hops (Humulus lupulus L.). However, to the best of our knowledge, the genetic and epigenetic stability of the microplants has never been tested before. In the present study, two hop accessions were established in vitro and micropropagated for 2 years. The genetic and epigenetic stability of the in vitro plants was analyzed with several molecular techniques: random amplified DNA polymorphism (RAPD), retrotransposon microsatellite amplified polymorphism (REMAP), and methylation-sensitive amplification polymorphism (MSAP). No genetic variation among control and treated plants was found, even after 12 cycles of micropropagation. Epigenetic variation was detected, first, when field and in vitro samples were compared. Nearly a 30% of the detected fragments presented the same pattern of alterations in all the vitroplants. Second, lower levels of epigenetic variation were detected among plants from the different subcultures. Part of this detected variation seemed to be accumulated along the 12 sequential subcultures tested.
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Jakse J, Cerenak A, Radisek S, Satovic Z, Luthar Z, Javornik B. Identification of quantitative trait loci for resistance to Verticillium wilt and yield parameters in hop (Humulus lupulus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2013; 126:1431-43. [PMID: 23423654 DOI: 10.1007/s00122-013-2062-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 02/08/2013] [Indexed: 05/11/2023]
Abstract
Verticillium wilt (VW) can cause substantial yield loss in hop particularly with the outbreaks of the lethal strain of Verticillium albo-atrum. To elucidate genetic control of VW resistance in hop, an F1 mapping population derived from a cross of cultivar Wye Target, with the predicted genetic basis of resistance, and susceptible male breeding line BL2/1 was developed to assess wilting symptoms and to perform QTL mapping. The genetic linkage map, constructed with 203 markers of various types using a pseudo-testcross strategy, formed ten major linkage groups (LG) of the maternal and paternal maps, covering 552.98 and 441.1 cM, respectively. A significant QTL for VW resistance was detected at LOD 7 on a single chromosomal region on LG03 of both parental maps, accounting for 24.2-26.0 % of the phenotypic variance. QTL analysis for alpha-acid content and yield parameters was also performed on this map. QTLs for these traits were also detected and confirmed our previously detected QTLs in a different pedigree and environment. The work provides the basis for exploration of QTL flanking markers for possible use in marker-assisted selection.
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Bauerle WL. Disentangling photoperiod from hop vernalization and dormancy for global production and speed breeding. Sci Rep 2019; 9:16003. [PMID: 31690783 PMCID: PMC6831652 DOI: 10.1038/s41598-019-52548-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 10/21/2019] [Indexed: 11/17/2022] Open
Abstract
Humulus lupulus L. (hop) flowers are a key ingredient in beer, imparting the beverage's aroma and bitterness profile. Photoperiod is known to interact with temperature to control flowering in hops. Studies have stipulated that resting dormant buds on hops require a minimum chilling duration for their meristems to break dormancy and grow fruitfully. This assertion, in part, led to a long-held notion that hops require vernalization and/or dormancy for the meristem to change from a vegetative to floral state. The research in this study aims to separate photoperiod from vernalization and dormancy through a series of experiments that artificially control photoperiod to prevent the onset of dormancy and chilling exposure. Six experiments were performed to assess flower yield and quality for seven diverse hop cultivars (with and without exposure to chilling and dormancy) to quantify the impact on flowering performance. Vernalization and dormancy, two plant traits previously considered necessary to the proliferation of hop flowers, do not influence hop flower yield and quality. The findings have broad implications; global hop production can be distributed more widely and it paves the way for speed breeding and controlled-environment production to achieve 4 hop generation cycles per year, as opposed to 1 under field-grown conditions.
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Matousek J, Kocábek T, Patzak J, Skopek J, Maloukh L, Heyerick A, Fussy Z, Roldán-Ruiz I, Keukeleire DD. HlMyb3, a putative regulatory factor in hop (Humulus lupulus L.), shows diverse biological effects in heterologous transgenotes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:7767-76. [PMID: 17708645 DOI: 10.1021/jf071153+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A hop-specific cDNA library from glandular tissue-enriched hop cones was screened for Myb transcription factors. cDNA encoding for R2R3 Myb, designated HlMyb3, was cloned and characterized. According to the amino acid (aa) sequence, HlMyb3 shows the highest homology to GhMyb5 from cotton and is unrelated to the previously characterized HlMyb1 from the hop. Southern blot analyses indicated that HlMyb3 is a unique gene, which was detected in various Humulus lupulus cultivars, but not in Humulus japonicus. Reverse transcription and real-time PCR revealed the highest levels of HlMyb3 mRNA in hop cones at a late stage of maturation and in colored petiole epidermis, while the lowest levels were observed in hop flowers. Two alternative open reading frames starting in the N-terminal domain of HlMyb3, encoding for proteins having 269 and 265 amino acids with apparent molecular masses of 30.3 and 29.9 kDa, respectively, were analyzed as transgenes that were overexpressed in Arabidopsis thaliana, Nicotiana benthamiana, and Petunia hybrida plants. Transformation with the longer 269 aa variant designated l-HlMyb3 led to a flowering delay and to a strong inhibition of seed germination in A. thaliana. Nearly complete flower sterility, dwarfing, and leaf curling of P. hybrida and N. benthamiana l-HlMyb3 transgenotes were noted. On the contrary, the shorter 265-aa-encoding s-HlMyb3 transgene led in A. thaliana to the stimulation of initial seed germination, to fast initiation of the lateral roots, and to quite specific branching phenotypes with many long lateral stems formed at angles near 90 degrees . Limited plant sterility but growth stimulation and rather branched phenotypes were evident for s-HlMyb3 transgenotes of P. hybrida and N. benthamiana. It was found that both HlMyb3 transgenes interfere in the accumulation and composition of flavonol glycosides and phenolic acids in transformed plants. These effects on heterologous transgenotes suggest that the HlMyb3 gene may influence hop morphogenesis, as well as metabolome composition during lupulin gland maturation.
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Batista D, Fonseca S, Serrazina S, Figueiredo A, Pais MS. Efficient and stable transformation of hop (Humulus lupulus L.) var. Eroica by particle bombardment. PLANT CELL REPORTS 2008; 27:1185-1196. [PMID: 18369628 DOI: 10.1007/s00299-008-0537-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 02/22/2008] [Accepted: 03/06/2008] [Indexed: 05/26/2023]
Abstract
To the best of our knowledge, this is the first accurate and reliable protocol for hop (Humulus lupulus L.) genetic transformation using particle bombardment. Based on the highly productive regeneration system previously developed by us for hop var. Eroica, two efficient transformation protocols were established using petioles and green organogenic nodular clusters (GONCs) bombarded with gusA reporter and hpt selectable genes. A total of 36 hygromycin B-resistant (hyg(r)) plants obtained upon continuous selection were successfully transferred to the greenhouse, and a first generation group of transplanted plants was followed after spending a complete vegetative cycle. PCR analysis showed the presence of one of both transgenes in 25 plants, corresponding to an integration frequency of 69.4% and an overall transformation efficiency of 7.5%. Although all final transformants were GUS negative, the integration frequency of gusA gene was higher than that of hpt gene. Petiole-derived transgenic plants showed a higher co-integration rate of 76.9%. Real-time PCR analysis confirmed co-integration in 86% of the plants tested and its stability until the first generation, and identified positive plants amongst those previously assessed as hpt (+) only by conventional PCR. Our results suggest that the integration frequencies presented here, as well as those of others, may have been underestimated, and that PCR results should be taken with precaution not only for false positives, but also for false negatives. The protocols here described could be very useful for future introduction of metabolic or resistance traits in hop cultivars even if slight modifications for other genotypes are needed.
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Sousa Silva M, Margarida Fortes A, Sanchéz Testillanob P, Risueño MDC, Salom'e Pais M. Differential expression and cellular localization of ERKs during organogenic nodule formation from internodes of Humulus lupulus var. Nugget. Eur J Cell Biol 2004; 83:425-33. [PMID: 15506566 DOI: 10.1078/0171-9335-00397] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression and subcellular localization of extracellular signal-regulated kinase 1 or 2 (ERK1/2) homologues (HLERK1/2) during the process of organogenic nodule formation in Humulus lupulus var. Nugget was studied using antibodies specific for ERK1 and ERK2, and for phosphorylated mitogen-activated protein kinases (MAPKs). The increase in HLERK levels, detected by Western blotting 12 hours after wounding suggests their involvement in response to the wounding treatment applied for morphogenesis induction. In dividing cambial cells, occurring in between 4 and 7 days after morphogenesis induction, as well as in dividing prenodular cells (15 days after induction) HLERK1 and/or 2 were localized in the nucleus. However, as soon as nodular cells start proliferating to form shoot meristems, HLERK1 and 2 were detected in the cytoplasm and not in the nucleus. The data reported account for a differential expression and activation of HLERK1 and HLERK2 throughout the process of nodule formation and plantlet regeneration. HLERK1 appears to be expressed in the stages of nodule formation and plantlet regeneration, playing a possible role in controlling cell proliferation and differentiation. HLERK2 may be induced as a response to reactive oxygen species (ROS) generated by wounding of internodes as its expression is reduced in liquid medium with less oxygen availability compared to solid medium. However, addition of a ROS inhibitor to the liquid medium does not result in a further decrease in the HLERK2 level.
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Undas AK, Weihrauch F, Lutz A, van Tol R, Delatte T, Verstappen F, Bouwmeester H. The Use of Metabolomics to Elucidate Resistance Markers against Damson-Hop Aphid. J Chem Ecol 2018; 44:711-726. [PMID: 29978430 PMCID: PMC6096525 DOI: 10.1007/s10886-018-0980-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/17/2018] [Accepted: 06/25/2018] [Indexed: 11/24/2022]
Abstract
Phorodon humuli (Damson-hop aphid) is one of the major pests of hops in the northern hemisphere. It causes significant yield losses and reduces hop quality and economic value. Damson-hop aphid is currently controlled with insecticides, but the number of approved pesticides is steadily decreasing. In addition, the use of insecticides almost inevitably results in the development of resistant aphid genotypes. An integrated approach to pest management in hop cultivation is therefore badly needed in order to break this cycle and to prevent the selection of strains resistant to the few remaining registered insecticides. The backbone of such an integrated strategy is the breeding of hop cultivars that are resistant to Damson-hop aphid. However, up to date mechanisms of hops resistance towards Damson-hop aphids have not yet been unraveled. In the experiments presented here, we used metabolite profiling followed by multivariate analysis and show that metabolites responsible for hop aroma and flavor (sesquiterpenes) in the cones can also be found in the leaves, long before the hop cones develop, and may play a role in resistance against aphids. In addition, aphid feeding induced a change in the metabolome of all hop genotypes particularly an increase in a number of oxidized compounds, which suggests this may be part of a resistance mechanism.
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Hecht S, Kammhuber K, Reiner J, Bacher A, Eisenreich W. Biosynthetic experiments with tall plants under field conditions. 18O2 incorporation into humulone from Humulus lupulus. PHYTOCHEMISTRY 2004; 65:1057-1060. [PMID: 15110685 DOI: 10.1016/j.phytochem.2003.08.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 08/18/2003] [Indexed: 05/24/2023]
Abstract
Five segments of a large hop plant (Humulus lupulus var. Hallertauer Magnum) carrying several cones were enclosed in sealed glass vessels that were gassed with (18)O(2). After 14 days, the segments were harvested and humulone and cohumulone were analysed by NMR spectroscopy and mass spectroscopy. The oxygen atoms in position 6 of humulone and cohumulone showed 9% (18)O enrichment, respectively. It follows that the C-6 hydroxy groups were introduced by oxygenase catalysis.
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Woods JL, James DG, Lee JC, Walsh DB, Gent DH. Development of biological control of Tetranychus urticae (Acari: Tetranychidae) and Phorodon humuli (Hemiptera: Aphididae) in Oregon hop yards. JOURNAL OF ECONOMIC ENTOMOLOGY 2014; 107:570-581. [PMID: 24772536 DOI: 10.1603/ec13488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The temporal development of biological control of arthropod pests in perennial cropping systems is largely unreported. In this study, the development of biological control of twospotted spider mite, Tetranychus urticae Koch, and hop aphid, Phorodon humuli (Schrank), in a new planting of hop in Oregon is described over a period of 9 yr (2005-2013). Both the abundance and diversity of natural enemies increased over time. Known predators of hop aphid (Coccinellidae and Anthocoridae) were present in all years; however, stable biological control of hop aphid was not achieved in most years and aphicides were required to suppress populations at commercially acceptable levels in 5 of 9 yr. Populations of aphidophagous coccinellids developed synchronously with hop aphid populations, and temporal correlations indicated these are the primary predatory insect associated with hop aphid regulation. However, sampling methods did not assess levels of aphid parasitoids and hyperparasitoids and their contribution to biological control was unquantified. Spider mite biological control was associated primarily with predatory mites (Phytoseiidae) and Stethorus spp. (Coccinellidae). The magnitude of temporal correlations of abundance of these predators with spider mites was found to be greatest on the same sampling dates and at lags of 7-14 d. Stable biological control of spider mites occurred after four field seasons, suppressing spider mites to levels similar to those commonly achieved with chemical control. A survey of 11 commercial hop yards in Oregon documented pest and natural enemy densities under commercial management practices over a period of 4 yr (2008-2011). Natural enemy abundance in commercial hop yards was similar to that of a 2- to 3-yr-old hop yard with limited disturbance. Whereas total reliance on biological control for hop aphid is unlikely to be successful, there appears to be unrealized potential for biological control of spider mites in commercial production. Dynamic action thresholds that consider the value of natural enemies are needed for both pests.
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Kavalier AR, Pitra NJ, Koelling JM, Coles MC, Kennelly EJ, Matthews PD. Increase in cone biomass and terpenophenolics in hops ( Humulus lupulus L.) by treatment with prohexadione-calcium. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:6720-6729. [PMID: 21598976 DOI: 10.1021/jf200677y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Humulus lupulus L. (hop), a specialty crop bred for flavor characteristics of the inflorescence, is an essential ingredient in beer. Hop inflorescences, commonly known as hop cones, contain terpenophenolic compounds, which are important for beer flavoring and of interest in biomedical research. Hop breeders focus their efforts on increasing cone biomass and terpenophenolic content. As an alternative to traditional breeding, hops were treated with prohexadione-calcium (Pro-Ca), a growth inhibitor previously shown to have positive agronomic effects in several crops. Application of Pro-Ca to hop plants during cone maturation induced increases in cone biomass production by 1.5-19.6% and increased terpenophenolic content by 9.1-87.3%; however, some treatments also induced significant decreases in terpenophenolic content. Induced changes in cone biomass production and terpenophenolic accumulation were most dependent on cultivar and the developmental stage at which plants were treated.
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Woods JL, Dreves AJ, Fisher GC, James DG, Wright LC, Gent DH. Population density and phenology of Tetranychus urticae (Acari: Tetranychidae) in hop is linked to the timing of sulfur applications. ENVIRONMENTAL ENTOMOLOGY 2012; 41:621-635. [PMID: 22732621 DOI: 10.1603/en11279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The twospotted spider mite, Tetranychus urticae Koch, is a worldwide pest of numerous agronomic and horticultural plants. Sulfur fungicides are known to induce outbreaks of this pest on several crops, although mechanisms associated with sulfur-induced mite outbreaks are largely unknown. Studies were conducted during 2007-2009 in Oregon and Washington hop yards to evaluate the effect of timing of sulfur applications on T. urticae and key predators. In both regions, applications of sulfur made relatively late in the growing season (mid-June to mid-July) were associated with the greatest exacerbation of spider mite outbreaks, particularly in the upper canopy of the crop. The severity of mite outbreaks was closely associated with sulfur applications made during a relatively narrow time period coincident with the early exponential phase of spider mite increase and rapid host growth. A nonlinear model relating mean cumulative mite days during the time of sulfur sprays to the percent increase in total cumulative mite days (standardized to a nontreated plot) explained 58% of the variability observed in increased spider mite severity related to sulfur spray timing. Spatial patterns of spider mites in the Oregon plots indicated similar dispersal of motile stages of spider mites among leaves treated with sulfur versus nontreated leaves; however, in two of three years, eggs were less aggregated on leaves of sulfur-treated plants, pointing to enhanced dispersal. Apart from one experiment in Washington, relatively few predatory mites were observed during the course of these studies, and sulfur-induced mite outbreaks generally occurred irrespective of predatory mite abundance. Collectively, these studies indicate sulfur induces mite outbreaks through direct or indirect effects on T. urticae, mostly independent of predatory mite abundance or toxicity to these predators. Avoidance of exacerbation of spider mite outbreaks by sulfur sprays was achieved by carefully timing applications to periods of low spider mite abundance and slower host development, which is generally early to mid-spring for hop.
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Calvert D, Dew T, Gadon A, Gros J, Cook D. Valorisation of hop leaves for their bioactive compounds: Identification and quantification of phenolics across different varieties, crop years and stages of development. Food Chem 2025; 465:142005. [PMID: 39577263 DOI: 10.1016/j.foodchem.2024.142005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 10/18/2024] [Accepted: 11/09/2024] [Indexed: 11/24/2024]
Abstract
Hop leaves, a by-product from hop cone harvesting, contain phenolic compounds of potential value for food or beverage applications. However, the abundant phenolics in hop leaves remain largely unquantified. This study quantified phenolics in hop leaves over two crop years, for three commercially significant varieties, at different developmental stages post-flowering. Ethanolic hop extracts were characterised using LC-ESI-qTOF-MS/MS and HPLC-DAD for the annotation and quantification of phenolics and bitter resins. Hop leaf phenolic profile exhibited considerable structural diversity, differing significantly from that of respective cones. Kaempferol/quercetin 3-O-glycosides and chlorogenic acids were the most abundant sub-groups with phenolic acids, procyanidins, prenylflavonoids and bitter resins also present. Phenolic profile was mainly variety-dependent with some crop year and developmental effects. Flavonol 3-O-glycosides were the main compounds driving varietal differences. Findings demonstrate the structural diversity and high concentrations of phenolic compounds in hop leaf extracts and their potential as a source of bioactives for valorisation.
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