Integration of Transcriptomics and WGCNA to Characterize Trichoderma harzianum -Induced Systemic Resistance in Astragalus mongholicus for Defense against Fusarium solani

Beneficial fungi of the genus are among the most widespread biocontrol agents that induce a plant's defense response against pathogens. is one of the main pathogens that can negatively affect production and quality. To investigate the impact of on defense responses to , roots under + (T + F) treatment and (F) treatment were sampled and subjected to transcriptomic analysis. A differential expression analysis revealed that 6361 differentially expressed genes (DEGs) responded to induction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the 6361 DEGs revealed that the genes significantly clustered into resistance-related pathways, such as the plant-pathogen interaction pathway, phenylpropanoid biosynthesis pathway, flavonoid biosynthesis pathway, isoflavonoid biosynthesis pathway, mitogen-activated protein kinase (MAPK) signaling pathway, and plant hormone signal transduction pathway. Pathway analysis revealed that the , formononetin biosynthesis, biochanin A biosynthesis, and , ROS production, and may be upregulated by and play important roles in disease resistance. Our study further revealed that the H O content was significantly increased by induction. Formononetin and biochanin A had the potential to suppress . Weighted gene coexpression network analysis (WGCNA) revealed one module, including 58 DEGs associated with induction. One core hub gene, , was found to be upregulated by , SA (salicylic acid) and ETH (ethephon). Overall, our data indicate that can induce induced systemic resistance (ISR) and systemic acquired resistance (SAR) in . The results of this study lay a foundation for a further understanding of the molecular mechanism by which induces resistance in .