Xiong Qiangqiang, Wu Han, Wang Runnan, Tang Siqi, Luo Haihua
Research Institute of Rice Industrial Engineering Technology, Yangzhou University, Yangzhou 225009, China.
Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou 225009, China.
Plants (Basel). 2024 Dec 3;13(23):3389. doi: 10.3390/plants13233389.
Antioxidant activity and flavonoid content are important characteristics of colored rice grains. Previously, we obtained a preliminary understanding of the metabolic markers of antioxidant activity, namely, phlorizin and trilobatin, in different colored rice varieties and purple rice grains at different growth stages, but the mechanisms associated with these markers have not yet been confirmed. In this study, purple rice was selected as the experimental material, and clover extract was applied during the grain-filling stage to explore the impact of clover extract on the total antioxidant capacity and flavonoid biosynthesis in purple rice grains. The results indicated that the total flavonoid content, total phenolic content, oligomeric proanthocyanidin content, and total antioxidant capacity of purple rice grains treated with an exogenous application of trilobatin (T30) were significantly greater than those of the control (CK). The flavonoids in the T30 and CK groups accounted for 29.81% of the total flavonoids. The phenylpropanoid biosynthesis and flavonoid biosynthesis metabolic pathways were constructed on the basis of the differentially abundant metabolites between the T30 and CK groups. Additionally, 1-O-sinapoyl-beta-D-glucose, coniferaldehyde, 6″-acetylapiin, and kaempferol-3-O-rutinoside were determined to be essential metabolites for trilobatin-mediated flavonoid biosynthesis in purple rice. The correlation network diagram between biochemical indexes and metabolites revealed that 1-O-sinapoyl-beta-D-glucose, coniferaldehyde, 6″-acetylapiin, and kaempferol-3-O-rutinoside were important metabolites. This study provides a scientific basis for improving the nutritional quality of rice grains and understanding the flavonoid biosynthesis pathway.
抗氧化活性和黄酮类化合物含量是有色稻米的重要特性。此前，我们已初步了解了不同有色水稻品种及不同生长阶段紫米籽粒中抗氧化活性的代谢标志物，即根皮苷和三叶苷，但与这些标志物相关的机制尚未得到证实。本研究选取紫米作为实验材料，在灌浆期施加三叶草提取物，以探究三叶草提取物对紫米籽粒总抗氧化能力及黄酮类生物合成的影响。结果表明，外源施加三叶苷（T30）处理的紫米籽粒总黄酮含量、总酚含量、原花青素低聚物含量和总抗氧化能力均显著高于对照（CK）。T30组和CK组中的黄酮类化合物占总黄酮类化合物的29.81%。基于T30组和CK组之间差异丰富的代谢物构建了苯丙烷生物合成和黄酮类生物合成代谢途径。此外，确定1-O-芥子酰基-β-D-葡萄糖、松柏醛、6″-乙酰芹菜素和山奈酚-3-O-芸香糖苷是紫米中三叶苷介导的黄酮类生物合成的关键代谢物。生化指标与代谢物之间的相关网络图显示，1-O-芥子酰基-β-D-葡萄糖、松柏醛、6″-乙酰芹菜素和山奈酚-3-O-芸香糖苷是重要的代谢物。本研究为提高稻米营养品质及了解黄酮类生物合成途径提供了科学依据。
