title: Metabolic Profile and Root Development of Hypericum perforatum L. In vitro Roots under Stress Conditions Due to Chitosan Treatment and Culture Time.
abstract: The responses of Hypericum perforatum root cultures to chitosan elicitation had been investigated through (1)H-NMR-based metabolomics associated with morpho-anatomical analyses. The root metabolome was influenced by two factors, i.e., time of culture (associated with biomass growth and related "overcrowding stress") and chitosan elicitation. ANOVA simultaneous component analysis (ASCA) modeling showed that these factors act independently. In response to the increase of biomass density over time, a decrease in the synthesis of isoleucine, valine, pyruvate, methylamine, etanolamine, trigonelline, glutamine and fatty acids, and an increase in the synthesis of phenolic compounds, such as xanthones, epicatechin, gallic, and shikimic acid were observed. Among the xanthones, brasilixanthone B has been identified for the first time in chitosan-elicited root cultures of H. perforatum. Chitosan treatment associated to a slowdown of root biomass growth caused an increase in DMAPP and a decrease in stigmasterol, shikimic acid, and tryptophan levels. The histological analysis of chitosan-treated roots revealed a marked swelling of the root apex, mainly due to the hypertrophy of the first two sub-epidermal cell layers. In addition, periclinal divisions in hypertrophic cortical cells, resulting in an increase of cortical layers, were frequently observed. Most of the metabolic variations as well as the morpho-anatomical alterations occurred within 72 h from the elicitation, suggesting an early response of H. perforatum roots to chitosan elicitation. The obtained results improve the knowledge of the root responses to biotic stress and provide useful information to optimize the biotechnological production of plant compounds of industrial interest.
authors.affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Brasili
authors.affiliation: Department of Chemistry, "Sapienza" University of Rome Rome, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Miccheli
authors.affiliation: Department of Chemistry, "Sapienza" University of Rome Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Marini
authors.affiliation: Department of Chemistry, "Sapienza" University of Rome Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Praticò
authors.affiliation: Department of Chemistry, "Sapienza" University of Rome Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Sciubba
authors.affiliation: Department of Chemistry, "Sapienza" University of Rome Rome, Italy.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Di Cocco
authors.affiliation: Núcleo de Investigações Químico-Farmacêuticas/CCS, Universidade do Vale do Itajaí Itajaí, Brazil.
authors.forename: Valdir Filho
authors.initials: VF
authors.lastname: Cechinel
authors.affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.
authors.forename: Noemi
authors.initials: N
authors.lastname: Tocci
authors.affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Valletta
authors.affiliation: Department of Environmental Biology, "Sapienza" University of Rome Rome, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pasqua
keywords: ASCA modeling; Hypericum perforatum; NMR spectroscopy; chitosan elicitation; metabolomics; root culture