The role of cell wall phenolics during the early remodelling of cellulose-deficient maize cells. (February 2020)

• Record Type: Journal Article
• Authors: Martínez-Rubio, Romina; Centeno, María Luz; García-Angulo, Penélope; Álvarez, Jesús M.; Acebes, José Luis; Encina, Antonio
• Is Part Of: Phytochemistry. Volume 170(2020)
• Publication Date: 2020-02
• Subjects: Zea mays L. -- Poaceae -- Maize -- HPLC -- Hydroxycinnamates -- Cell wall -- p-coumaric acid -- Ferulic acid -- Dichlobenil; AX arabinoxylan -- CA p-coumaric acid -- DCB 2, 6-dichlorobenzonitrile or dichlobenil -- DFA dehydrodiferulate -- FA ferulic acid -- H 1.5 μM dichlobenil-habituated cultures -- NH non-habituated cultures -- PDA photodiode array detection -- TFA trifluoroacetic acid; Botanical chemistry -- Periodicals; Biochemistry -- Periodicals; Botany -- Periodicals; Chimie végétale -- Périodiques; 572.2
• DOI: 10.1016/j.phytochem.2019.112219
• Languages: English
• ISSNs: 0031-9422

Abstract

Abstract: The habituation of cultured cells to cellulose biosynthesis inhibitors such as dichlobenil (dichlorobenzonitrile, DCB) has proven a valuable tool to elucidate the mechanisms involved in plant cell wall structural plasticity. Our group has demonstrated that maize cells cope with DCB through a modified cell wall in which cellulose is replaced by a more extensive network of highly cross-linked feruloylated arabinoxylans. In order to gain further insight into the contribution of phenolics to the early remodelling of cellulose-deficient cell walls, a comparative HPLC-PAD analysis was carried out of hydroxycinnamates esterified into nascent and cell wall polysaccharides obtained from non-habituated (NH) and habituated to low DCB concentrations (1.5 μM; H) maize suspension-cultured cells. Incipient DCB-habituated cell walls showed significantly higher levels of esterified ferulic acid and p -coumaric acid throughout the culture cycle. In terms of cell wall fortification, ferulic acid is associated to arabinoxylan crosslinking whereas the increase of p -coumaric suggests an early lignification response. As expected, the level of hydroxycinnamates esterified into nascent polysaccharides was also higher in DCB-habituated cells indicating an overexpression of phenylpropanoid pathway. Due to their key role in cell wall strengthening, special attention was paid into the dimerization pattern of ferulic acid. A quantitative comparison of diferulate dehydrodimers (DFAs) between cell lines and cell compartments revealed that an extra dimerization took place in H cells when both nascent and mature cell wall polysaccharides were analysed. In addition, qualitative differences in the ferulic acid coupling pattern were detected in H cells, allowing us to suggest that 8-O-4′-DFA and 8-5′-DFA featured the ferulic acid dimerization when it occurred in the protoplasmic and cell wall fractions respectively. Both qualitative and quantitative differences in the phenolic profile between NH and H cells point to a regioselectivity in the ferulate dehydrodimerization. Graphical abstract: Structural model of the primary cell wall of dichlobenil-habituated maize suspension-cultured cells showing the interactions between cellulose, arabinoxylans and phenolic compounds. Image 1 Highlights: Phenolic profile of DCB-habituated cells shows quantitative and qualitative features. Intra-protoplasmic and cell wall extra dimerization occurs in DCB-habituated cells. 8-O-4′-DFA and 8-5′-DFA increases during DCB-habituation. A regioselectivity in the ferulate dehydrodimerization is proposed.