First report of aspergillus sydowii ASP17 as a promising biological control agent against soil-borne fungal and fungal-like plant pathogens: A laboratory study

This study aimed to investigate the antagonistic properties of the Aspergillus sydowii ASP17 isolate against soil-borne fungal and like-fungal pathogens including Rhizoctonia solani, Phytophthora nicotianae, and Pythium aphanidermatum under in vitro experiments. The results showed that A. sydowii ASP17 inhibited 57.4% growth of R. solani, 45.4% of P. nicotianae, and 53.3% of P. aphanidermatum in a dual culture test. In the second experiment, A. sydowii ASP17 showed inhibition rates of 72.7% for R. solani, 45.9% for Ph. nicotianae, and 56% for P. aphanidermatum. The highest efficacy in the dual culture test was observed against R. solani, but in the volatile organic compounds test, the highest efficacy was against P. aphanidermatum. The ASP17 isolate acted by antibiosis by forming inhibition zones caused by the antifungal substances without contact with the pathogen. This study also investigated the production of volatile organic compounds, hydrogen cyanide, and the cell wall-degrading enzymes protease and lipase, which may be related to the biocontrol activity of the isolate. The production of hydrogen cyanide was also examined in the A. sydowii ASP17 isolate. These data could support the potential use of A. sydowii ASP17 as a biocontrol agent in agriculture, especially in environments where the use of chemical fungicides is undesirable.