Abstract: Tobacco root rot caused by Fusarium spp. is one of the most serious soil-borne diseases affecting tobacco production. In this study, a fungus HY31, which can antagonize seven Fusarium species, was isolated from the rhizosphere soil of tobacco plants infected with Fusarium root rot in Xiangxi Autonomous Prefecture, Hunan Province by using the plate-confrontation assay. It was identified as Trichoderma asperellum based on morphological characteristics and internal transcribed spacer (ITS) sequencing. Further studies showed that strain HY31 not only has the ability to solubilize potassium and both organic and inorganic phosphorus, but can also directly inhibit Fusarium mycelial growth, parasitize Fusarium mycelia, and indirectly activate the expression of tobacco defense genes. Pot experiments indicated that HY31 had a control efficacy of 61.53% against tobacco Fusarium root rot and also exhibited significant growth-promoting effects on tobacco plants. This study identified Trichoderma asperellum HY31 as a promising biocontrol agent for tobacco Fusarium root rot, providing an excellent candidate resource for the biological control of this disease.
Keywords: tobacco Fusarium root rot; Fusarium spp. ; Trichoderma asperellum; biological control; pot experiment
（Acta Laser Biology Sinica, 2026, 35(4): 337-346）