Metabolomic Analysis Revealed the Differences in Metabolites Between Three Different Sugarcane Stems and Leaves.

Sugarcane is an important sugar crop. Sugarcane stems are mainly used for sugar extraction, while leaves can only be burned as waste. However, sugarcane leaves can also produce a large number of secondary metabolites, and these metabolites have significant nutritional and pharmacological value. At present, there are few studies on sugarcane compounds. Therefore, the stems and leaves of three sugarcane varieties (Yacheng 89-159, Dianzhe 01-58, ROC22) were selected as experimental materials, and the compounds of stems and leaves of different sugarcane were studied using high-performance liquid chromatography. Metabolomics analysis detected 1197 metabolites that could be broadly divided into 11 categories. Orthogonal partial least squares discriminant analysis identified metabolites that were differentially abundant across groups (stems and leaves within and across the three varieties). Flavonoids, phenolic acids, and lipids were the main differential metabolites. Notably, tricin-4'-O-(guaiacylglycerol)ether-7-O-glucoside, quercetin-3,4-O-di-glucoside, cyanidin-3-O-(6''-O-malony)glucoside were significantly higher in the stems than in the leaves across all three varieties. The content of methylenesuccinic acid was higher in the leaves of Dianzhe 01-58 and ROC22. In the comparative analysis of the top 20 differential metabolites among different varieties, it was found that the metabolite content of stems and leaves of Yacheng 89-9 and ROC22 was significantly higher than that of Dianzhe 01-58. Next, KEGG analysis showed that these differential metabolites were mainly enriched in pathways related to flavonoid, phenylpropanoid, and isoflavonoid biosynthesis, as well as starch and sucrose metabolism. Leaves also had significantly fewer metabolites involved in starch and sucrose metabolism than stems did. In conclusion, this study provides a scientific basis for utilization of sugarcane compounds, laying a theoretical foundation for further processing of sugarcane by-products into higher-value materials.