Transcriptomic and Metabolomic Analyses Reveal the Phenylpropanoid Metabolism Regulatory Network in Arabidopsis Response to Colletotrichum higginsianum Infection

Colletotrichum higginsianum (Ch) is a typical hemibiotrophic ascomycetous fungus. The diseases it causes often lead to considerable economic losses in global cruciferous crop production. However, current knowledge is still insufficient for us to gain a deeper understanding of how host plants respond at the transcriptional level during Ch infection. Herein, we performed transcriptomic and metabolic assays between Mock and Ch- infected samples. The results showed that Ch infection significantly inhibited the shoot fresh weight and primary root length of host plants. Furthermore, gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to phenylpropanoid metabolism were highly enriched. Defense hormone salicylic acid (SA) and three metabolites belonging to the phenylpropanoid metabolism pathway were identified. Meanwhile, we screened 5 related enzyme-encoding genes and 78 transcription factors (TFs). Five WRKY, three MYB, and two NAC TFs showed significant expression changes and high correlation with enzyme genes. Our results enrich regulatory networks in crucifier pathogen responses. This work provides potential molecular candidates to support subsequent studies on the mechanisms underlying Ch resistance.