Metabolomic Diversity in Polygonatum kingianum Across Varieties and Growth Years

Polygonatum rhizome is a traditional Chinese medicine of the same origin as food and medicine, and it has high economic value and social benefits. To screen the excellent germplasm resources of Polygonatum kingianum (P. kingianum) and clarify the nutritional and medicinal value of the rhizome of P. kingianum, we used widely targeted metabolomics to analyze the traits and metabolomics of rhizomes of different germplasms of P. kingianum from different growth years. The results showed that different germplasms and growth years of P. kingianum were rich in different nutritional and medicinal components. Among them, Polygonatum kingianum 'Linyun 1' rhizome (PWR) was richer in amino acids and derivatives, alkaloids, and phenolic acids, while Polygonatum kingianum rhizome (PRR) was richer in flavonoids, organic acids, and phenolic acids. Most of the differential compounds were mainly enriched in PRR when the growth year was one, and PWR had a greater variety and higher content of differential compounds in the third year, which also reflected the advantages of Polygonatum kingianum 'Linyun 1' (P. kingianum 'Linyun 1') as an excellent new variety of P. kingianum. The Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis showed that in P. kingianum with the same age and different germplasms, the significantly enriched metabolic pathway was more active in biosynthesis in PWR. In the same germplasm of P. kingianum from different years, the metabolites involved in PRR were mainly the highest in one-year-old P. kingianum (PR-1) or three-year-old P. kingianum (PR-3), and the metabolites involved in PWR were mainly the highest in three-year-old P. kingianum 'Linyun 1' (PW-3). The above results showed that the three-year-old PWR had more advantages based on chemical substances. Therefore, this study provided a new theoretical reference for the development of P. kingianum products and the breeding of new varieties.