Peppers are widely consumed in Korea; the varietal development of peppers with increased content of beneficial plant metabolites is, therefore, of considerable interest. This requires a comprehensive understanding of the metabolic profile of pepper plants and the factors affecting this profile. To this end, we determined the content of various metabolites, such as hydrophilic and lipophilic compounds, phenolic acids, carotenoids, and capsaicinoids in peppers of various colors (green, red, pale green, and violet peppers) and in a high-pungency (green) pepper. We also performed principal component analysis (PCA), Pearson's correlation analysis, and hierarchical clustering analysis (HCA) to determine the relationships among these metabolites in peppers. PCA results indicated no significant variances among the 3 sample replicates. The HCA showed correlations between the metabolites resulting from common or closely linked biosynthesis pathways. Our results showed that carotenoids correlated positively with tocopherols and negatively with phytosterols; our findings also indicated a close relationship between the methylerythritol 4-phosphate and mevalonic acid biosynthesis pathways, providing evidence in favor of an earlier hypothesis regarding crosstalk across the chloroplast membrane. We, thus, demonstrate that metabolic profiling combined with multivariate analysis is a useful tool for analyzing metabolic networks. PRACTICAL APPLICATION A total of 71 metabolites were measured in 5 peppers of different colors. The metabolic profiling with multivariate analysis revealed that tocopherol content had a positive correlation with the carotenoid content and a negative correlation with the phytosterol content. The results of this study may help in breeding programs to produce new germplasm with enhanced nutritional quality.

中文翻译：

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各种颜色辣椒的代谢物分析揭示了生育酚、类胡萝卜素和植物甾醇含量之间的关系

辣椒在韩国被广泛消费；因此，具有增加的有益植物代谢物含量的辣椒的品种开发具有相当大的兴趣。这需要全面了解辣椒植物的代谢特征以及影响该特征的因素。为此，我们测定了各种颜色的辣椒（绿色、红色、浅绿色和紫罗兰色辣椒）中各种代谢物的含量，如亲水性和亲油性化合物、酚酸、类胡萝卜素和辣椒素，并以高刺激性（绿皮书。我们还进行了主成分分析 (PCA)、皮尔逊相关分析和层次聚类分析 (HCA) 以确定辣椒中这些代谢物之间的关系。PCA 结果表明 3 个样品重复之间没有显着差异。HCA 显示了由共同或密切相关的生物合成途径产生的代谢物之间的相关性。我们的研究结果表明，类胡萝卜素与生育酚呈正相关，与植物甾醇呈负相关；我们的研究结果还表明甲基赤藓糖醇 4-磷酸和甲羟戊酸生物合成途径之间存在密切关系，为早期关于叶绿体膜串扰的假设提供了证据。因此，我们证明代谢分析与多变量分析相结合是分析代谢网络的有用工具。实际应用 在 5 个不同颜色的辣椒中测量了总共 71 种代谢物。多变量分析的代谢谱显示，生育酚含量与类胡萝卜素含量呈正相关，与植物甾醇含量呈负相关。这项研究的结果可能有助于育种计划以产生具有更高营养质量的新种质。