A novel Trichoderma asperellum isolate promoting the growth, detoxification, and antifungal abilities of Arabidopsis thaliana seedlings under Fusarium oxysporum toxin stress

A new Trichoderma asperellum strain, TasT1, was isolated from the rhizosphere of Malus sieversii in Xinjiang Region of China. Its antifungal ability was evaluated by controlling root rot Fusarium oxysporum (Fox68) of M. sieversii. The results showed that TasT1 inhibited the growth of Fox68, with an inhibition rate of 66.7%. After treating Arabidopsis thaliana seedlings with different concentrations of TasT1 fermentation liquor, the root hair density of the seedlings changed significantly. Treatment with 60% fermentation liquor caused the root length to increase by 21%, and the fresh weight by 80%. Furthermore, TasT1 fermentation liquor improved the detoxification ability of A. thaliana seedlings against Fox68 toxin and greatly alleviated leaf wilting. Defense-related enzymes (e.g., peroxidase, POD) activity and malondialdehyde content of A. thaliana increased significantly. In addition, in the TasT1 + Fox68 group, the expression levels of PDF1.2B, PDF1.2C, and PR1 were upregulated by 5.2, 5.1, and 2.2 times respectively after treatment for 3 d. Meanwhile, we used GC-MS analysis of chemical component of TasT1 fermentation liquor and found that TasT1 fermentation liquor include 49 kinds of ingredients which contain a lot of antibacterial substances. Our findings suggest that TasT1 fermentation liquor could induce the accumulation of defense-related enzymes to improve disease resistance and growth of A. thaliana seedlings. TasT1 has the potential to control F. oxysporum (Fox68) and protect M. sieversii.