The Effect Of Biotic Elicitors (Aspergillus Species) On Enrichment And Accumulation Of Glyceollins In Soybean Seeds

One of the best and longest-studied defense responses of plants to infection is the inducedaccumulation of antimicrobial, low-molecular-weight secondary metabolites known as phytoalexins. Arole for these compounds in defense has been revealed through several experimental approaches. Severalisoflavonoid phytoalexins produced by soybeans are known to be estrogenic, with potential beneficialhealth effects in humans, an example is the glyceollins.PURPOSE: Given the preventive effect of soy intake against several chronic diseases, this study wasconducted to investigate the effect of biotic elicitor in the induction and accumulation of glyceollinsisolated from soybean seeds elicited with selected strains of Aspergillus Sojae and Oryzae.METHODS: Soybean was used as the main raw material, two Aspergillus species were tested and bothelicited phytoalexins accumulation in living soybean cotyledons of the Chinese and Nigerian varieties ofsoybean seeds used. Among the two cultures method experimented the pre-soaked soybean seeds in waterfor4-5hrs were found to be suitable for high glyceollin induction. Glyceollins I, II, and III weredetermined by HPLC, MS, UPLC MS/MS analysis. And separation of glyceollin from other isoflavonoidscompounds was achieved by HSCCC and the Prep-HPLC.RESULTS: HSCCC separation yielded6.0mg of glyceollins and with purity>86.90%. The conditions ofsoybean seed varieties treated with biotic elicitor (Aspergillus Sojae and Oryzae) were experimentedthrough a single-factor experiment. Optimal parameters were determined by investigating the effects ofthe concentration of A. oryzae Lu brewing3042, the soak time, temperature and time course experiment.The optimal conditions of elicitation were as follows: concentration of A. oryzae20μL was found to bemost suitable for induction, pre-soaked seed time in distilled water for5hrs was suitable for the Chinesevariety of soybean seeds and4hrs soak time was suitable for the Nigerian variety of soybean seeds, acontrolled temperature of25oC was found to be the best for both varieties of soybean used, incubation inthe dark was for3days. An optimum condition protocol was carried out from the total result conditionsgotten from the single factor experiment for glyceollin induction from soybean elicited with the selectedmicro strains of A. oryzae. Results from the optimal conditions study indicated that in the cut surface ofNigerian soybean seed following elicitation with A. oryzae Lu brewing3042contained0.40mg/g andelicitation with A. sojae contained0.70mg/g of glyceollins and where as in selected Chinese soybeanvariety upon elicitation with A. oryzae Lu brewing3042contained1.50mg/g and elicitation with A. sojaecontained2.26mg/g of glyceollins dry weight respectively.CONCLUSION: These findings identify the effects of biotic elicitor on glyceollin induction andaccumulation in soybean seeds. And that phytoalexin glyceollin merit further study as potential therapeuticagents for human health, which can be further utilized to evaluate chemical components of soybeansamples for plant biology, food science and pharmaceutical studies.