On the biocontrol by Trichoderma afroharzianum against Fusarium culmorum responsible of fusarium head blight and crown rot of wheat in Algeria

摘要

Durum wheat (Triticum durum Desf.) is one of the most important cereals in the world. Unfortunately, the wheat plant is a target of several species of the genus Fusarium. This genus causes two serious diseases: fusarium crown rot (FCR) and fusarium head blight (FHB). The search for new indigenous strains of Trichoderma with a high potential for biocontrol against these two diseases was the purpose of this study. Biocontrol potential of 15 isolates of Trichoderma (T1 to T15), isolated from different rhizosphere soils and Algerian ecosystems, was evaluated against 4 strains of Fusarium culmorum (FC11, FC2, FC4, and FC20); the main causative agent of FCR and FHB. The efficacy of biological control by Trichoderma spp., evaluated by in vitro tests (direct and indirect confrontation), was confirmed by in vivo bioassays. The in vitro results showed a significant inhibition of mycelial growth of F. culmorum species than the control. The highest percentages of inhibition were obtained by T9, T12, and T14 isolates causing a maximum inhibition percentage of 81.81, 77.27, and 80.68%, respectively. T14 was selected for biocontrol in in vivo testing. A tube and pot experiments for FCR against F. culmorum showed that T14 decreased the disease severity with 50 and 63.63% reduction, respectively. FHB infection was significantly reduced by T14 in all durum wheat cultivars tested, where %AUDPC (area under the disease progress curve) reduction was 49.77, 43.43, 48.25, and 74.60% for Simeto, Waha, Bousselem, and Setifis genotypes, respectively. Yields also increased significantly for almost all cultivars. The antagonistic T14 was characterized based on molecular tools, using translation elongation factor1-alpha (TEF1-α) and internal transcribed spacers rDNA (ITS1). The results identified T14 as T. afroharzianum with accession numbers attributed by NCBI GenBank as MW171248 and MW159753. Trichoderma afroharzianum, evaluated for the first time in Algeria as biocontrol agent, is a promising biocontrol approach against FCR and FHB.