Work

Biocontrol efficacy of Trichoderma asperellum TA-1 against Rhizoctonia solani AG-3 and its underlying mechanisms

Year: 2026

Type: article

Abstract: Introduction Rhizoctonia solani Kühn is a globally distributed soilborne pathogen responsible for severe diseases in various crops, including rice, wheat, tobacco, and maize, causing substantial economic losses. This study characterized a Trichoderma strain, TA-1, with significant biocontrol efficacy against tobacco target spot disease. Methods TA-1 was isolated and identified through morphological characterization and molecular analysis as Trichoderma asperellum . Qualitative assays were conducted to assess ammonia production and laccase, amylase, and protease activities. Solid-state fermentation trials were performed to optimize spore production conditions, and greenhouse assays were conducted to evaluate biocontrol efficacy. Microscopy, scanning electron microscopy, and transcriptomic analyses were used to characterize the interaction between TA-1 and R. solani AG-3. Results Qualitative assays indicated ammonia production and laccase, amylase, and protease activities in TA-1. The optimal spore production conditions were wheat bran substrate, 0.5% glucose, 1.5% ammonium sulfate, a water-to-substrate ratio of 1:1, and a fermentation duration of 6 days, under which the spore yield reached 4.74 × 10 9 CFU/g dry substrate. Greenhouse assays showed that both TA-1 spore suspension and fermentation filtrate significantly suppressed disease symptoms caused by R. solani AG-3, with the spore suspension exhibiting stronger inhibition. Microscopy and scanning electron microscopy revealed clear mycoparasitic features during the TA-1–AG-3 interaction, including hyphal attachment and coiling, structural damage to pathogen hyphae, and colonization of the sclerotial surface. Transcriptomic analysis further identified strong upregulation of TrAFT101_005492 , encoding a CFEM domain protein (log 2 FC = 4.99), and TrAFT101_000974 , encoding a lipoxygenase (log 2 FC = 4.73), suggesting their potential association with the mycoparasitic interaction. Discussion Overall, T. asperellum TA-1 possesses broad antagonistic activity and considerable biocontrol potential, supporting its further evaluation as a biological control agent for sustainable disease management.

Source: Frontiers in Microbiology

DOI: 10.3389/fmicb.2026.1899737