The phenolic profile of maize primary cell wall changes in cellulose-deficient cell cultures

Cultured maize cells habituated to grow in the presence of the cellulose synthesis inhibitor dichlobenil (DCB) have a modified cell wall in which the amounts of cellulose are reduced and the amounts of arabinoxylan increased. This paper examines the contribution of cell wall-esterified hydroxycinnamates to the mechanism of DCB habituation. For this purpose, differences in the phenolic composition of DCB-habituated and non-habituated cell walls, throughout the cell culture cycle and the habituation process were characterized by HPLC. DCB habituation was accompanied by a net enrichment in cell wall phenolics irrespective of the cell culture phase. The amount of monomeric phenolics was 2-fold higher in habituated cell walls. Moreover, habituated cell walls were notably enriched in p-coumaric acid. Dehydrodimers were 5-6-fold enhanced as a result of DCB habituation and the steep increase in 8,5'-diferulic acid in habituated cell walls would suggest that this dehydrodimer plays a role in DCB habituation. In summary, the results obtained indicate that cell wall phenolics increased as a consequence of DCB habituation, and suggest that they would play a role in maintaining the functionality of a cellulose impoverished cell wall.