【Objective】 Rice false smut, caused by Ustilaginoidea virens, is a global fungal disease that severely impacts rice yield and quality. Understanding the molecular mechanisms behind U. virens pathogenicity could inspire novel control strategies and molecular breeding for disease resistance. 【Method】 Transcriptome and metabolome analyses were conducted on the initial symptomatic panicle nine days after inoculation (S) and uninoculated PXD25 mycelium (CK). The genome of strain UV-8b served as the reference for sequence alignment. Gene expression levels were quantified using fragments per kilobase per million fragments (FPKM), and differentially expressed genes (DEGs) were identified using |LOG2 fold change|≥1 and q-value≤0.05 criteria. Differentially accumulated metabolites (DAM) were identified with P≤0.05 and VIP≥1 thresholds. 【Result】 In the S vs. CK comparison, 6078 DEGs were identified. GO enrichment analyses revealed 3708 terms, and KEGG pathway analysis identified 110 metabolic pathways. Ninety-one transcription factors (TFs) belonging to 23 TF families, such as bZIP and C2H2, were among the DEGs. Significant enrichment of mitophagy, secondary metabolism, and amino acid metabolism pathways was observed, with upregulation of DEGs in secondary metabolic pathways suggesting their crucial role in U. virens pathogenesis. Additionally, 392 DAMs were identified, including alanine, tyrosine, histidine, methionine, cysteine, and fatty acids (linoleic acid, palmitic acid, lauric acid, myristic acid), indicating their association with U. virens pathogenicity. Combined transcriptome and metabolome analysis highlighted enrichment in amino acid metabolic pathways (e.g., phenylalanine, tyrosine, cysteine, and methionine) and carbohydrate-related pathways (e.g., starch and sucrose). 【Conclusion】 DEGs involved in mitophagy, secondary metabolism, and amino acid metabolism, along with DAMs like alanine, tyrosine, histidine, methionine, cysteine, and fatty acids, are closely linked to U. virens pathogenicity.
