Organogenic Nodule Formation in Hop: A Tool to Study Morphogenesis in Plants with Biotechnological and Medicinal Applications

Abstract

The usage of Humulus lupulus for brewing increased the demand for high-quality plant material. Simultaneously, hop has been used in traditional medicine and recently recognized with anticancer and anti-infective properties. Tissue culture techniques have been reported for a wide range of species, and open the prospect for propagation of disease-free, genetically uniform and massive amounts of plants in vitro. Moreover, the development of large-scale culture methods using bioreactors enables the industrial production of secondary metabolites. Reliable and efficient tissue culture protocol for shoot regeneration through organogenic nodule formation was established for hop. The present review describes the histological, and biochemical changes occurring during this morphogenic process, together with an analysis of transcriptional and metabolic profiles. We also discuss the existence of common molecular factors among three different morphogenic processes: organogenic nodules and somatic embryogenesis, which strictly speaking depend exclusively on intrinsic developmental reprogramming, and legume nitrogen-fixing root nodules, which arises in response to symbiosis. The review of the key factors that participate in hop nodule organogenesis and the comparison with other morphogenic processes may have merit as a study presenting recent advances in complex molecular networks occurring during morphogenesis and together, these provide a rich framework for biotechnology applications.

Transcriptional Modulation of Polyamine Metabolism in Fruit Species Under Abiotic and Biotic Stress

“…PAs are growth regulators that have been implicated in abiotic and biotic stresses (Cona et al, 2006; Cuevas et al, 2008; Marina et al, 2008; Alcázar et al, 2010; Gonzalez et al, 2011; Nambeesan et al, 2012; Agudelo-Romero et al, 2014; Minocha et al, 2014; Pál et al, 2015), as well as in plant morphogenesis and development (Applewhite et al, 2000; Fortes et al, 2010, 2011; Tiburcio et al, 2014; Jancewicz et al, 2016), senescence (Pandey et al, 2000; Sobieszczuk-Nowicka, 2017), and fruit development and ripening (Mattoo and Handa, 2008; Agudelo-Romero et al, 2013, 2014; Tavladoraki et al, 2016). Several publications have suggested that the role played by these growth regulators in plant–microbe interactions is either exerted directly by PAs functioning as signaling molecules or mediated through the products of their catabolism together with jasmonic acid (JA), abscisic acid (ABA), salicylic acid (SA), auxins, cytokinins, and ethylene (Jiménez-Bremont et al, 2014).…”

Arginine Decarboxylase expression, polyamines biosynthesis and reactive oxygen species during organogenic nodule formation in hop

“…31 It may be that the huge amount of PAs detected in hop nodules 28 days after culture initiation are also related to differential auxin fluxes inside nodules which may lead to organization of nodular vascular centers to which future regenerated plantlets will be connected to. 19,20 It is noteworthy in this context that hop nodules contain higher levels of IAA than internodes. 32 In Scots pine, at the early developmental stages of zygotic embryogenesis there is typically an increasing trend in PA concentrations and a decreasing trend during late embryo development.…”

“…Hop, besides being an important ingredient in beer, has very promising health-promoting and medicinal properties given mainly by specific polyphenols. 18,19 In spite of its economical importance, hop is extremely sensitive to several pathogens. Therefore, it is important to continue research towards understanding factors involved on in vitro plant regeneration.…”

Establishment of an Efficient Micropropagation System for Humulus lupulus L. cv. Cascade and Confirmation of Genetic Uniformity of the Regenerated Plants through DNA Markers

“…Humulus lupulus L., commonly known as hop, is a dioecious perennial, climbing plant, belonging to the Cannabaceae family native to Northern temperate climates [1]. Hop plants have a long and proven history of their use in herbal medicine, mainly due to their sedative, tonic and calming effect [2], but its importance in beer production as a main ingredient remains of great value [3]. Female hop inflorescences (hops, cones or strobiles) have been used in traditional medicine to treat neurological and gynecological disorders [4,5].…”