Quantitative sensitivity of 12 isoflavones among different organs of soybean seedlings in the application of UV-B

다국어 초록 (Multilingual Abstract)

Organ-specific isoflavone accumulation of UV-B irradiated soybean seedlings remains, incompletely understood, although the effects of UV-B on growth and secondary metabolite production have been widely studied. Isoflavone content increases during soybean seed germination and further increases by approximately 2.5 times when UV-B is applied to soybean seedlings. Compared to dark conditions, UV-B treatment for at least 2 days at 1 W·m−2 or higher is significant, leading to a maximum isoflavone content of 1636.40 mg/100g. The degree of increase in isoflavone content varies by seedling organ: cotyledons show an increase of 1.5-fold, hypocotyls 50-fold, and roots 12-fold, with the dry weight ratio of these organs 9.5:3.8:1. The compound contributing most significantly to this increase is malonyl daidzin, which increases approximately 650-fold in the hypocotyls under UV-B treatment compared to dark conditions, while in roots and cotyledons, the increase is 2.3-fold and 13-fold, respectively. These findings highlight the hypocotyls as the most sensitive organ to UV-B-induced isoflavone accumulation. This study can provide fundamental knowledge for the targeted accumulation of specific isoflavones using UV-B.

목차 (Table of Contents)

• 1. Introduction 1
• 2. Materials and Methods 3
• 2.1. Plant materials and Ultraviolet-B (UV-B) irradiation conditions 3
• 2.2. Growth measurement of soybean seedlings and total chlorophyll content of cotyledon 4
• 2.3. Isoflavone extraction 4
• 2.4. Reverse-phased high performance liquid chromatography (HPLC) analysis of isoflavone 4
• 2.5 Statistical analysis 5
• 3. Results and discussion 6
• 3.1. Seedling growth and chlorophyll content 6
• 3.2. Total isoflavone content in soybean seedlings irradiated with UV-B . 11
• 3.3. Individual isoflavone content in cotyledon of soybean seedlings irradiated with UV-B 14
• 3.4. Individual isoflavone content in hypocotyl of soybean seedlings irradiated with UV-B 17
• 3.5. Individual isoflavone content in root of soybean seedlings irradiated with UV-B 20
• 3.6. Principal component analysis (PCA) of isoflavone accumulation according to UV-B exposure time and light intensity 23
• 4. Conclusion 26
• References 27