Cloning and Functional Analysis of tri14 in Trichoderma brevicompactum

Trichodermin, one of the trichothecenes, is a potential antifungal antibiotic and a protein synthesis inhibitor. Trichodermin is synthesized mainly by Trichoderma brevicompactum, but the biosynthetic pathway has yet been completely elucidated. Our earlier transcriptome assay on the trichodermin synthesis in T. brevicompactum 0248 identified a unique tri14 transcript, designated Tbtri14, that was co-regulated with other tri cluster genes. However, the function of this gene remains unknown. In this study, the full cDNA and DNA sequence of Tbtri14 was isolated from T. brevicompactum 0248. It was found the Tbtri14 gene encodes 364 amino acids with a 59 bp intron. For gene function study, the Tbtri14 was deleted in the 0248 strain. The silencing of Tbtri14 dramatically increased the transcription of Tbtri11, it had little influence on the expression of Tbtri4 and Tbtri5 as well as the production of trichodermin in △tri14 deletion mutants. This implied that Tbtri14 may not be directly involved in trichodermin biosynthesis. Instead, it may act as a gene regulator, such as a repressor for Tbtri11.