Control Mechanism of Metabolism of Oligosaccharins Regulating Plant Growth

来自植物或真菌细胞壁的某些类型的低聚糖具有不同的生理活性。这些活性低聚糖被称为“寡糖”，似乎参与了高等植物生命周期的调节。据报道，低聚木葡聚糖在植物生长调节中起重要作用。本研究旨在阐明木葡聚糖低聚糖的代谢是如何在细胞壁网络中原位调节的。考察了木葡聚糖非糖（XG9或XXFG）和焦酰基乳糖对不同生长过程的影响。XG9和聚焦基乳糖均不影响生长素或酸诱导的红豆上胚轴片段的伸长，赤霉素酸诱导的完整生菜下胚轴的生长，以及苯ladenin诱导的萝卜子叶的伸长。采用酶联免疫吸附法（ELISA）测定内源性木葡聚糖低聚糖的浓度，并采用抗体和吡啶层合荧光标记的新微量法测定。木葡聚糖低聚糖的水平估计为10^<-8> M或更低。用1 M NaCl从红豆上胚轴细胞壁制备中提取了两种可能参与低聚木葡聚糖生产和降解的酶。用Con A-Sepharose、Mono-S、Superdex 75和Phenyl Superose色谱柱纯化木葡聚糖水解酶（内切-1,4-葡聚糖酶）和α -聚焦酶。这两种酶都由几个同工酶组成。在Mono-S柱上，内切-1,4- β -葡聚糖酶与纤维素酶明显分离，并表现出不同的作用模式。-聚焦酶不能水解红硝基- α - l-岩藻糖苷，对木葡聚糖侧链具有特异性。

Certain types of oligosaccharide derived from plant or fungal cell walls possess diverse physiological activities. These active oligosaccharides, called "oligosaccharins" appear to be involved in the regulation of life cycle of higher plants. It has been reported that xyloglucan oligosaccharides play an important role in growth regulation. The present study was undertaken to clarify how the metabolism of the xyloglucan oligosaccharins is regulated in situ in the cell wall network.1.The effect of xyloglucan nonasaccharide (XG9 or XXFG) and fucosyl-lactose on different growth processes was examined. Neither XG9 nor fucosyl-lactose did influence auxin- or acid-induced elongation of azuki bean epicotyl segments, gibberellic acid-induced growth of intact lettuce hypocotyls, or benzyladenine-induced expansion of radish cotyledons.2.The endogenous concentration of xyloglucan oligosaccharides was determined with ELISA assay employing antibodies specific for the oligosaccharides and with new microassay using the antibodies and pyridylamination fluorescence labeling. The level of xyloglucan oligosaccharides was estimated as 10^<-8> M or lower.3.Two types of enzyme that appear to be involved in the production and the degradation of xyloglucan oligosaccharides were extracted with 1 M NaCl from the cell wall preparation of azuki bean epicotyls. Xyloglucan-hydrolyzing enzymes (endo-1,4-beta-glucanase) and alpha-fucosidases were purified with Con A-Sepharose, Mono-S, Superdex 75, and Phenyl Superose columms. Both enzymes were composed of several isozymes. The endo-1,4-beta-glucanases were clearly separated from cellulase on a Mono-S column and exhibited different action patterns. alpha-Fucosidases did not hydrolyze rho-nitrophenyl-alpha-L-fucopyranoside and were specific for xyloglucan side chains.