Metabolomics and Transcriptomics Reveal Key Metabolism Pathways of Giant Embryo Development in Rice. Metabolomics and Transcriptomics Reveal Key Metabolism Pathways of Giant Embryo Development in Rice

Rice embryos are rich in high-quality protein, fat, vitamins and minerals, representing the most important nutritional part of brown rice. However, the molecular mechanism of rice embryo development is poorly understood. In this study, map-based cloning, metabolomics, and transcriptomics were applied to explore the giant embryo rice cultivar Dapeimi grown under natural conditions. The map-based cloning results demonstrated that Dapeimi is a novel allelic mutant of GE, and the functional mutation site is a single cytosine deletion in the exon1, which differed from the findings of previous reports. The identification and analysis of differential metabolites indicated that plants lacking the GE mainly promoted amino acid metabolism, energy metabolism, and lipid metabolism pathways in the rice embryo. Changes of gene expression in related metabolic regulatory networks were analyzed, and substantial changes in the transcriptome supported the metabolomics results. By analyzing rice embryo development through a combination of strategies, this research contributes to a greater understanding of the molecular mechanism of rice embryo development, and provides a theoretical foundation for improving rice nutrition and breeding high-nutrition varieties. Overall design: embryo mRNA profiles of 15-day old NIL-D (EG) and NIL-X (CG) were generated by deep sequencing in triplicates

水稻胚富含优质蛋白质、脂肪、维生素与矿物质，是糙米最核心的营养组成部分。然而，当前对于水稻胚发育的分子调控机制仍知之甚少。本研究采用图位克隆、代谢组学与转录组学技术，对自然种植条件下的大胚水稻品种Dapeimi开展探究。图位克隆结果显示，Dapeimi为GE的新型等位突变体，其功能性突变位点为外显子1区域的单个胞嘧啶缺失，这与既往研究报道的结果存在差异。差异代谢物的鉴定与分析表明，GE功能缺失的水稻胚主要激活了氨基酸代谢、能量代谢与脂质代谢通路。对相关代谢调控网络中的基因表达变化进行分析后发现，转录组的显著变化印证了代谢组学的分析结果。本研究通过多技术联用策略解析水稻胚发育过程，有助于深化对水稻胚发育分子机制的认知，并为改良稻米营养品质与培育高营养水稻品种提供了理论依据。整体实验设计：对15日龄的NIL-D（EG）与NIL-X（CG）水稻胚的mRNA转录谱进行深度测序，每个样本设置三次生物学重复。