Biological activity of some Romanian and Turkish Trichoderma Pers. strains

Disease infections caused by invasive fungi and bacteria, are some of the major causes of agricultural losses and food contamination. Human pathogenic infections are diminishing the quality of life, and in severe cases, they can trigger morbidity or even mortality. In the agricultural field, preventive treatments should be provided to control plant diseases, while in the healthcare system, for suppressing human pathogens infections, curative measures can also be applied, but with enormous costs in many parts of the world. To diminish these shortcomings, three Trichoderma spp. strains were screened in this study for antimicrobial and antibiofilm activities. The antifungal effect of these strains was evaluated against eight common plant pathogenic fungi: Alternaria sp. Nees, Botrytis cinerea Pers., Fusarium culmorum (Wm.G.Sm.) Sacc., F. graminearum Schwabe, F. oxysporum Schltdl., F. proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg, Macrophomina phaseolina (Tassi) Goid. and Sclerotinia sclerotiorum (Lib.) de Bary. Tested Trichoderma spp. strains reduced the pathogenic growth with at least 50% inhibition; however, they were most effective against B. cinerea, with up to 92.1 ± 2.0% inhibition. The antibacterial activity of the crude extract obtained from liquid cultures of tested Trichoderma spp. strains was also screened against six opportunistic human pathogens and food contaminants: Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper-Bälz, Escherichia coli (Migula) Castellani & Chalmers, Listeria monocytogenes (Murray et al.) Pirie, Pseudomonas aeruginosa (Schroeter) Migula, Salmonella typhimurium (Loeffler) Castellani & Chalmers and Staphylococcus aureus Rosenbach. Antibacterial activity was determined by disc diffusion assay, and tested Trichoderma spp. strains revealed particularly high inhibitory activity against gram positive bacteria. Moreover, the antibiofilm activity of these three biocontrol strains was also screened by XTT Assay kit. Turkish Trichoderma sp. Ș4 strain showed significant inhibitory activity against the tested pathogens.