3.5 | Metabolomic comparison of fenced and unfencedR. multiflora plants
We conducted untargeted metabolomics analysis on all R. multiflora samples and identified 1,350 metabolite features. Even though the samples tend to separate from each other on the PCA plot based on treatment (fence vs no fence), the PCA did not group the samples into distinct clusters (Figure 6A ). To inspect the treatment-based differences in the metabolite profile of the plants, we conducted PLS-DA (Figure 6B ) and identified the top 15 features that varied significantly across the treatments (Figure 6C ). We followed this analysis with HCA to obtain a filtered set of 25 metabolites that consistently and significantly varied between the fence and no fence samples. The heatmap generated from the HCA analysis indicates that the top 25 metabolites clearly differentiate the fence and no fence samples (Figure 6D ). The GSEA tool in Metaboanalyst was used to identify some putative metabolic pathways that the metabolomic features are associated with, including the pentose phosphate pathway (P = 0.04) and carbon fixation in photosynthetic organisms (P = 0.04) (Appendix Table 5 ); though carbon fixation is not directly related with plant defense, the pentose phosphate pathway is implicated with stress responses in plants .