Trichothecium roseum epigenetic reader Snt2 in phenotype and pathogenicity regulation

As an epigenetic reader, Snt2 is involved in the regulation of phenotype and pathogenicity of some filamentous fungi. However, whether Snt2 is involved in the regulation of phenotype and pathogenicity of Trichothecium roseum has not been reported. In this study, snt2-deleted strain of T. roseum and its complementation were constructed based on bioinformatics analysis to investigate the effects of Trsnt2 on the phenotype and pathogenicity of T. roseum. The results showed that the Snt2 protein in T. roseum has a high homology to that of Fusarium albosuccineum. The protein contains one BAH domain, two PHD domains, one SANT domain and one ELM2 domain. Deletion of Trsnt2 inhibited colony growth, reduced aerial hyphae, decreased polar growth, and increased hyphal branching of T. roseum. In addition, the deletion of Trsnt2 downregulated the expression of key genes related to sporulation, including TrbrlA, TrabaA, and TrwetA, reducing sporulation but increasing spore germination. The Trsnt2 deletion strain was more sensitive to cell wall stress and oxidative stress, but not to osmotic stress. In addition, Trsnt2 deletion downregulated the expression levels of PacC, ammonia synthesisrelated genes (TrGDH2, TrAMET, TrGLT1, and TrMEPB), and extracellular enzyme-related genes (TrpelB, TrplyB, Trpme1, TrpgaX, TreglA, Trbgl1, Trcbh1, and Trcut1) in T. roseum. Deletion of Trsnt2 also reduced the pathogenicity of T. roseum on apple fruit. In conclusion, deletion of Trsnt2 inhibited the growth and development of T. roseum, reduced sensitivity of the strain to osmotic stress, but increased to cell wall and oxidative stress, and reduced the pathogenicity of the strain on apple fruit.