The comparative analysis and identification of secondary metabolites between Tibet wild and cultivated pomegranates (Punica granatum L.) in China

Secondary metabolites are closely related to the nutritional quality and health functions of plants. We investigated the secondary metabolites of both wild (n=23) and cultivated (n=27) pomegranate plants (Punica granatum L.) growing in China. The total flavonoid (TF) and tannin (TT) contents from the peel and juice were determined and the secondary metabolites in the peel (ZLP) and juice (ZLZ) of 'Zela 4' were identified using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Analysis of variance (P<0. 05) showed that there were significant differences in the TF content of peel (TF (P)) and juice (TF (J)), and the TT content of peel (TT (P)) and juice (TT (J)) among different pomegranate accessions. Pearson correlation analysis showed that latitude and altitude might be the main environmental factors affecting TF and TT contents in pomegranates. In this study, 279 secondary metabolites were identified in the ZLP and ZLZ. In addition, we report for the first time 227 secondary metabolites in pomegranates. Using orthogonal partial least squares discriminant analysis, 90 differential metabolites were identified in ZLP and ZLZ. In addition, we screened eight specific germplasms (high-TF (P), 'Junyong 3'; low-TF (P), 'Yanzhihong'; high-TF(J), 'Zela 4'; low-TF (J), 'Yudazi', high-TT (P), 'Junyong 4'; low-TT (P), 'Anba 1'; high-TT(J), 'Yeba 1'; and low-TT (J), 'Baihuayushizi'). The results of our study provide a reference for the development and utilization of wild pomegranate resources and pomegranate breeding in China.

Automated summary

Secondary metabolites in pomegranates are closely related to nutritional quality and health functions. A study on wild and cultivated pomegranate plants in China revealed significant differences in flavonoid and tannin contents among different accessions. Latitude and altitude were identified as main environmental factors affecting the content of secondary metabolites. Over 200 secondary metabolites were identified in pomegranates, with 90 differential metabolites identified in two specific parts of the plant. This study provides valuable insights for utilizing wild pomegranate resources and breeding programs in China.