Objective Based on RNA-sequencing, the differentially expressed genes, related signaling pathways and metabolic pathways in poplar responded to Fusarium solani (Mart.) Sacc inoculation were investigated, and the key genes involved in the interaction were screened. The present results will lay a foundation for further revealing the molecular mechanism underlying poplar resistance to F. solani (Mart.) Sacc.

MethodsThe roots of 2-month-old seedlings of 84K were inoculated with 1 × 10⁷ spores·mL⁻¹ of F. solani (Mart.) Sacc spore solution. Zero-hour (control group), 48 h and 72 h (inoculated groups) after inoculation, root tissues were taken for transcriptome sequencing to explore genes related to poplar response to F. solani (Mart.) Sacc infection.

Result (1) Compared with the control group, 8939 and 8246 DEGs (Differentially Expressed Genes) were detected in 48 h and 72 h inoculated samples, respectively. (2) GO analysis found that the differentially expressed genes were mainly enriched in single-organism process, response to stimulus, carbohydrate metabolism process, biological regulation and response to hormone. (3) KEGG pathway enrichment analysis showed that the DEGs were significantly enriched in glycolysis/gluconeogenesis, carbon metabolism, plant hormone signal transduction and phenylpropanoid biosynthesis. (4) The expressions of 21 genes in the SWEETs family of poplar were induced by F. solani (Mart.) Sacc. Ethylene receptor ETR, and the main components of the ethylene signaling pathway EIN3, ERF1, ERF2 were up-regulated. The expression levels of key enzyme genes involved in lignin synthesis including CCR, 4CL, C3’H and COMT were significantly increased.

Conclusion Poplar may respond to the invasion of F. solani (Mart.) Sacc by regulating sugar metabolism and transport, activating the ethylene signaling pathway, promoting lignin accumulation, and thickening cell wall.