KEGG metabolic pathway analysis
Next, differential metabolites of EI vs. EF and EICL vs. EFCL were performed using the KEGG website for online analysis using Metabo Analyst, which provided the following enrichment analysis (P <0.05). The results established that 23 DMs caused by endophytic infection were significantly enriched into 5 and 11 KEGG pathways before and after pathogen inoculation, respectively (Table 1; Fig. S3).
The effects of endophytes on the contents of lipids, flavonoids, and isoflavones in the host showed a decreasing trend (Table 1). On the contrary, the effects of endophytes on the contents of amino acids and phenols showed an increasing trend. For the other 8 DMs, the increase in the contents of 1-aminocyclopropane-1-carboxylic acid (ACC), 3-indoleacetic acid, and 4-methyl-5-thiazole was the most pronounced, and their contents in EI plants were much higher than those in EF, regardless of pathogen inoculation; gentisic acid, tyramine, and D-pipecolic acid were significantly accumulated in EI after pathogen inoculation.
Integrated transcriptome and metabolomics analysis