Recognition mechanism of β-1,3-oligosaccharide elicitor in plants

研究了β- 1,3-低聚葡萄糖诱导马铃薯组织中酚酰胺类化合物（PAC）产生的机理。a) Laminarin是一种源自海藻的β-1,3-葡萄糖低聚糖，具有pac诱导活性。采用^<13>C-NMR、ESI-mass和化学甲基化技术对层粘胶蛋白的结构进行了分析。b)检测了其他市售β- 1,3 -葡聚糖诱导pac的活性。酵母细胞壁的一种水不溶性成分Zymosan，已被证明可以激活哺乳动物的免疫系统，在马铃薯中也具有PAC诱导活性。β- 1,3 -葡萄糖七糖（Laminariheptaose）具有较弱的诱导子活性，提示糖结构中β- 1,3 -连锁对活性的重要性。为了评价糖中β-1,6-分支对PAC诱导活性的影响，制备了不含β-1,6-分支的β- 1,3 -葡萄糖低聚糖。凝块（β-1,3-糖苷）的水解成功地得到了具有合适DP的β-1,3-糖苷低聚物。详细考察了其引发子活性。d) N-p-Coumaroyloctopamine的绝对结构为S.e) β-1,3-葡聚糖激发子处理后，4种PAC生物合成相关酶PAL、4CL、THT和TyrDC的活性瞬间一致上调。

The mechanism of the induction of phenolic amide compounds (PAC) in potato tissues by β- 1,3-glucooligosaccharide was investigated.a) Laminarin is a β-1,3-glucooligosaccharide of seaweed origin, which has PAC-inducing activity. The structure of laminarin was analyzed using ^<13>C-NMR, ESI-mass, and chemical methylation techniques.b) The PAC-inducing activity of other commercially available β-1, 3-glucans was examined. Zymosan, a water insoluble fraction of yeast cell wall, which has been shown to activate the mammalian immune system, also had a PAC inducing activity in potato. Laminariheptaose, a liner β-1, 3-glucoheptasaccharide, had the weak elicitor activity, and the importance of the β-1, 3-linkage in the saccharide structure for the activity was suggested.c) A liner β-1, 3-glucooligosaccharide without β-1,6-branch was prepared in order to evaluate the effect of β-1, 6-branch in the saccharide on the PAC inducing activity. Hydrolysis of curdran (liner β-1, 3-glucopolysaccharide) successfully afforded the liner β-1,3- glucooligosaccharide with suitable DP.Its elicitor activity was examined in detail.d)Absolute structure of N-p-Coumaroyloctopamine, which represents the most part of PAC in potato, was determined to be S.e) Activity of four PAC-biosynthesis-related enzymes, PAL, 4CL, THT and TyrDC, was transiently up-regulated in a concerted manner by the β-1,3-glucan elicitor treatment.