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.

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细胞壁酚类物质在缺乏纤维素的玉米细胞早期重塑中的作用

培养细胞对纤维素生物合成抑制剂（如二氯苯甲腈（dichlorobenzonitrile，DCB））的适应已被证明是阐明植物细胞壁结构可塑性所涉及的机制的宝贵工具。我们的小组已经证明，玉米细胞通过修饰的细胞壁处理 DCB，其中纤维素被更广泛的高度交联的阿魏酰化阿拉伯木聚糖网络所取代。为了进一步了解酚类物质对缺乏纤维素的细胞壁早期重塑的贡献，对羟基肉桂酸酯进行了比较性 HPLC-PAD 分析，该羟基肉桂酸酯化为从非习惯化 (NH) 和习惯化中获得的新生和细胞壁多糖。至低 DCB 浓度 (1.5 μM; H) 玉米悬浮培养细胞。在整个培养周期中，初始 DCB 习惯的细胞壁显示出显着更高水平的酯化阿魏酸和对香豆酸。在细胞壁强化方面，阿魏酸与阿拉伯木聚糖交联有关，而对香豆素的增加表明早期木质化反应。正如预期的那样，在 DCB 习惯的细胞中酯化成新生多糖的羟基肉桂酸酯的水平也更高，表明苯丙烷途径的过度表达。由于它们在细胞壁强化中的关键作用，阿魏酸的二聚化模式受到了特别关注。细胞系和细胞区室之间二阿魏酸脱氢二聚体 (DFA) 的定量比较表明，当分析新生和成熟细胞壁多糖时，H 细胞中发生了额外的二聚化。此外，在 H 细胞中检测到阿魏酸偶联模式的质量差异，这使我们能够表明 8-O-4'-DFA 和 8-5'-DFA 在原生质和细胞中发生阿魏酸二聚化时具有特征。壁分数分别。NH 和 H 细胞之间酚类谱的定性和定量差异都表明阿魏酸脱氢二聚反应具有区域选择性。