HPLC-MS Evaluation of Mannuronic and Guluronic Acid in Bacterial Alginate from Azotobacter vinelandii and the Effect on Glyceollin Induction and Accumulation in Soybeans

Abstract

Aims: The objective of this study was to investigate the eliciting efficacy of bacterial alginate which was extracted from Azotobacter vinelandii in the induction of glyceollins and accumulation in soybeans. Methodology: The preparative high performance liquid chromatography (HPLC) was used to detect, separate and purify the alginate after extraction and ultra performance liquid chromatography – mass spectrometry (UPLC-MS) was used to detect the molecular weights of both the extracted alginate and the induced glyceollins in soybeans. Results: Bacterial alginate induced glyceollins synthesis in soybean seeds in high quantity. The optimal conditions of elicitation were as follows: concentration of bacterial alginate 60 µL presoaked in the sterile water for 5h, incubated at a controlled temperature of 30℃ and in the dark for 4 days. Alginate induction ability exhibited glyceollin-inducing activities of 1.775 (mg/g dry weight) while the control had no record of glyceollin induction.  The results demonstrated that a larger molecular weight or a higher G/M ratio might correlate with a higher glyceollin-induction activity. Conclusion: In conclusion; alginate could be introduced as relatively safe and efficient elicitor of high glyceollin accumulation in soybeans. The method for bacterial alginate extraction and its application in soybean seeds for glyceollin induction may be of practical use in the food.