MYB family genes have many functions and are widely involved in plant abiotic-stress responses. Erianthus fulvus is an important donor material for stress-resistance genes in sugarcane breeding. However, the MYB family genes in E. fulvus have not been systematically investigated. In this study, 133 EfMYB genes, including 48 Ef1R-MYB, 84 EfR2R3-MYB and 1 Ef3R-MYB genes, were identified in the E. fulvus genome. Among them, the EfR2R3-MYB genes were classified into 20 subgroups. In addition, these EfMYB genes were unevenly distributed across 10 chromosomes. A total of 4 pairs of tandemly duplicated EfMYB genes and 21 pairs of segmentally duplicated EfMYB genes were identified in the E. fulvus genome. Protein-interaction analysis predicted that 24 EfMYB proteins had potential interactions with 14 other family proteins. The EfMYB promoter mainly contains cis-acting elements related to the hormone response, stress response, and light response. Expression analysis showed that EfMYB39, EfMYB84, and EfMYB124 could be significantly induced using low-temperature stress. EfMYB30, EfMYB70, EfMYB81, and EfMYB101 responded positively to drought stress. ABA treatment significantly induced EfMYB1, EfMYB30, EfMYB39, EfMYB84, and EfMYB130. All nine genes were induced using MeJA treatment. These results provide comprehensive information on EfMYB genes and can serve as a reference for further studies of gene function.

Background: 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. Methods: 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. Results: 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. Conclusion: 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.