Tartary buckwheat (Fagopyrum tataricum) is an annual herbaceous plant of Fagopyrum in Polygonaceae, which is a high-quality crop that is homologous of medicine and food. The occurrence of Fagopyrum damping-off has seriously affected the promotion and development of Tartary buckwheat planting.This study conducted transcriptome analysis on Fagopyrum tataricum treated with jasmonic acid or salicylic acid, revealing that the expression pattern of the aspartic protease gene FtAPDSLX1 is induced by jasmonic acid or salicylic acid. Further analysis of FtAPDSLX1 expression levels in Fagopyrum tataricum with different resistance degrees revealed a significantly higher expression level of FtAPDSLX1 in Fagopyrum tataricum resistant to Rhizoctonia solanicompared than in susceptible materials. Using the representative variety of Fagopyrum tataricum, Chuanqiao No. 1, the FtAPDSLX1 gene was cloned. Bioinformatics analysis revealed that the coding sequence of the FtAPDSLX1 gene contains 1143 base pairs, encoding the protein consisting of 380 amino acids，while its promoter harbors multiple cis-elements associated with disease resistance. Examination of FtAPDSLX1 expression patterns unveiled its upregulation in Tartary buckwheat seedlings upon Rhizoctonia solaniand invasion, exhibiting pronounced tissue specificity. Phenotypic analysis of disease resistance in transgenic Arabidopsis lines harboring the FtAPDSLX1 gene underscored its role in enhancing resistance against Rhizoctonia solaniand .Furthermore, under pathogen stress, FtAPDSLX1 expression substantially increased in transgenic Arabidopsis, concomitant with heightened enzymatic activities of SOD and POD. These findings suggest that FtAPDSLX1 may participate in the defense mechanism against Rhizoctonia solaniin Fagopyrum tataricum. The functional validation and related research of FtAPDSLX1 provide a foundation for unraveling the molecular mechanisms underlying Fagopyrum tataricum"s resistance to Rhizoctonia solaniand for screening disease-resistant germplasm resources.