| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1225-2 | ||||
Resumo:Beneficial microorganisms play important functions to the tobacco plant health and growth promotion. Trichoderma spp. is a promising fungus for the development of future biological products, with renowned biocontrolling capacities. In this sense, Trichoderma afroharzianum is one of the more abundant specie found in agricultural soils from Argentina, including in tobacco soils from Salta province. In this study we analysed the antagonism of Trichoderma afroharzianum to control tobacco root pathogens. Two T. afroharzianum (Th15 and Th51) strains were evaluated against five soil-borne pathogens isolated from tobacco: Fusarium oxysporum (Fo12), Macrophomina phaseolina (Mp1T), Sclerotinia sclerotiorum (Ss1P), Phytophthora spp. (Phy1, Phy2) by a dual culture technique. Briefly, 8-mm diameter mycelial disks from the edge of 7 days-old cultures of each fungus (Th and pathogen) were simultaneously inoculated on Potato dextrose agar plates. The experimental design was completely randomized with six replications for each strain, including control plates (without Trichoderma). After 7 days post- incubation at 24 ± 2°C, the antagonistic activity was estimated by measuring the radius (mm) of the pathogen. Percentages of radial growth inhibition (%I) for each pathogen were calculated relative to control. The growth of all the tobacco root pathogens analysed were significantly inhibited by the two T. afroharzianum (Th15 and Th51) strains. Th15 were the most effective strain to reduce the Oomycetes growth with 73 %I and 67 %I for Phy2 and Phy1, respectively. Moreover, the growth of other root phytopathogens analysed were inhibited > 50%I with Th15 and Th51, with exception for Fo12 (41%I with Th51). These data showed that T. afroharzianum (Th15 and Th51) displays a broad spectrum of antagonistic activity against different tobacco root pathogens. Future studies to characterize the mechanisms of antifungal action are in progress. Palavras-chave: antagonism, antifungal, root pathogens, tobacco, Trichoderma Agência de fomento:PICT2020 N°4431, CIUNSA N° 2725, INTA PE I073 | |||||