Study On The Effects Of Oligosaccharides In The Induction Of Glyceollins From Soybean Seeds

Glyceollins are a category of phytoalexins, and phytoalexins are a low molecular weightantimicrobial compound that are synthesized de novo and accumulates in different plant tissues inresponse to stress. Glyceollins are found to have health benefits for humans and properties of chronicdisease prevention. Previous studies had shown that glyceollins can be isolated in cultivated soybeansthrough oligosaccharides elicitation. The aim of this study was to explore the elicitation of glyceollinsby different oligosaccharides, means of separation, purification and glyceollins accumulation in soybeanseeds.The preparative high performance liquid chromatography was selected to separate and purify theethanol extracts of elicited soybeans seeds with10mM AgNO3which was shown to be the activeelicitor. The separation process was monitored by HPLC and UPLC-MS/MS was used to detect theirmolecular weights. Separation of glyceollins was achieved by HPLC with a purity of93.96%.This research focus was majorly on the relationship among oligosaccharides elicitation andglyceollins accumulation in soybean seeds. In response to stress, soybean produces the phytoalexinsglyceollins with all three (I, II, and III) isomers observed. Six types oligosaccharide were used duringthis study and the results for their elicitation are as follow:0.1867mg/g dry weight elicited bycarrabiose oligosaccharides,0.1967mg/g dry weight elicited by pectic oligosaccharides,0.1804mg/gdry weight elicited by xylo-oligosaccharides,0.2412mg/g dry weigh elicited by alginateoligosaccharides,0.2537mg/g dry weight elicited by cello-oligosaccharide and0.1946mg/g dry weightelicited by chitosan oligosaccharide.The conditions of soybean cotyledons treated with alginate oligosaccharides were optimized throughthe single-factor experiments. The optimal parameters were determined by investigating the effects ofthe concentration of AOS, the soak time, temperature, moisture and time course experiment. Theoptimal conditions of elicitation were as follows: concentration of AOS4%, presoaked in the sterilewater for5h, stored at a controlled temperature of25℃and humidity of60%in the dark for4days.Results from the optimal conditions study indicated that maximum concentrations of the phytoalexinglyceollins was0.5679mg/g dry weight.