Iturin A Strongly Inhibits the Growth and T-2 Toxin Synthesis of Fusarium oxysporum: A Morphological, Cellular, and Transcriptomics Study
2023
Meifang Hua | Qi Deng | Mei Qiu | Yijia Deng | Lijun Sun | Zhijia Fang | Jianmeng Liao | Jian Zhao | Ravi Gooneratne
Fusarium oxysporum (F. oxysporum) is a common contaminant of dried fish, and the T-2 synthesis by this organism in dried fish products poses a serious public health risk. In this study, we investigated the effects of iturin A, a cyclic lipopeptide produced by Bacillus subtilis, on the growth and synthesis of the T-2 toxin of F. oxysporum, and transcriptomics was conducted. Results showed that the inhibitory effect of iturin A on F. oxysporum was significantly enhanced with an increase in iturin A concentrations. More specifically, compared with the control group, all indexes in the iturin A treatment group with 50 &mu:g/mL were decreased to 24.84 mm, 0.33 ×: 106 cfu/mL, and 5.86 ng/mL for the colony diameter, number of spores, and concentration of T-2 toxin, respectively. Furthermore, iturin A was proven to destroy the integrity of cell membranes and cause a significant increase in ROS at 25 &mu:g/mL or 50 &mu:g/mL. Transcriptomic analysis revealed that with the treatment of iturin A, the genes of the oxidation-reduction process were up-regulated, while the gene expression of mycelial growth, cell integrity, transmembrane transport, energy metabolism, and others were down-regulated. More importantly, the Tri5 gene cluster was significantly inhibited. This study provided new insights into the mechanism for the inhibitory effect of iturin A on the growth and T-2 toxin synthesis of F. oxysporum and theoretical guidance for the application of iturin A in the preservation of dried aquatic products.
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