title: Studying Secondary Growth and Bast Fiber Development: The Hemp Hypocotyl Peeks behind the Wall.
abstract: Cannabis sativaL. is an annual herbaceous crop grown for the production of long extraxylary fibers, the bast fibers, rich in cellulose and used both in the textile and biocomposite sectors. Despite being herbaceous, hemp undergoes secondary growth and this is well exemplified by the hypocotyl. The hypocotyl was already shown to be a suitable model to study secondary growth in other herbaceous species, namelyArabidopsis thalianaand it shows an important practical advantage, i.e., elongation and radial thickening are temporally separated. This study focuses on the mechanisms marking the transition from primary to secondary growth in the hemp hypocotyl by analysing the suite of events accompanying vascular tissue and bast fiber development. Transcriptomics, imaging and quantification of phytohormones were carried out on four representative developmental stages (i.e., 6-9-15-20 days after sowing) to provide a comprehensive overview of the events associated with primary and secondary growth in hemp. This multidisciplinary approach provides cell wall-related snapshots of the growing hemp hypocotyl and identifies marker genes associated with the young (expansins, β-galactosidases, and transcription factors involved in light-related processes) and the older hypocotyl (secondary cell wall biosynthetic genes and transcription factors).
authors.affiliation: Environmental Research and Innovation Department, Luxembourg Institute of Science and TechnologyEsch-sur-Alzette, Luxembourg; Groupe de Recherche en Physiologie Végétale, Earth and Life Institute-Agronomy, Université catholique de LouvainLouvain-la-Neuve, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Behr
authors.affiliation: Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology Esch-sur-Alzette, Luxembourg.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Legay
authors.affiliation: Institute of Experimental Botany, The Czech Academy of Sciences Prague, Czechia.
authors.forename: Eva
authors.initials: E
authors.lastname: Žižková
authors.affiliation: Institute of Experimental Botany, The Czech Academy of Sciences Prague, Czechia.
authors.forename: Václav
authors.initials: V
authors.lastname: Motyka
authors.affiliation: Institute of Experimental Botany, The Czech Academy of Sciences Prague, Czechia.
authors.forename: Petre I
authors.initials: PI
authors.lastname: Dobrev
authors.affiliation: Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology Esch-sur-Alzette, Luxembourg.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Hausman
authors.affiliation: Groupe de Recherche en Physiologie Végétale, Earth and Life Institute-Agronomy, Université catholique de Louvain Louvain-la-Neuve, Belgium.
authors.forename: Stanley
authors.initials: S
authors.lastname: Lutts
authors.affiliation: Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology Esch-sur-Alzette, Luxembourg.
authors.forename: Gea
authors.initials: G
authors.lastname: Guerriero
keywords: Cannabis sativa; RNA-Seq; bast fibers; cell wall; hypocotyl; immunohistochemistry; phytohormones