TIME ：12:40-14:00 July 21, 2021 (Wednesday)

VENUE：Room 104, Building B, School of Agriculture and Biology

ORGANIZER：Office of Discipline and Science & Technology, SAB; Young Teachers Association, SAB

TITTLE: Synthesis and regulation of Peptaibols in Trichoderma

ABSTRACT: 

Trichoderma is a kind of filamentous fungus genus widely existing in the soil environment. These fungi produce secondary metabolites such as peptaibols that have antimicrobial activities and plant growth promoters and as commercial biofungicides in agriculture and medicine. Peptaibols are a group of special antibacterial linear peptides rich in Aib synthesized by non-ribosomal peptide synthetases (NRPSs)，approximately 80 % of the known peptaibiotics today have been found in genus Trichoderma. Type I NRPS is the largest biosynthetic gene cluster and more than 10 NRPS modules (> 10000 AA) are loaded with about 10-25 amino acid precursors to synthesize peptaibols antimicrobial peptides. These long-chain antimicrobial peptides are the crucial metabolites that dominate the antibacterial activity of Trichoderma. The biosynthesis of peptaibols is regulated by the addition of specific amino acids, and also closely related to the growth conditions (different nitrogen and carbon sources) and spore formation.  Methyltransferase Lae1 is a global transcription regulator in Trichoderma, which regulates the formation of antagonistic metabolites. Our study showed that lae1 positively regulated the expression of several non-ribosomal peptide synthases, especially the peptide synthases and their flanking genes of NRPS (ID 317983, responsible for the synthesis of 19 residues of peptaibols). After lae1 was deleted, the production of some long-chain antimicrobial peptides decreased, while overexpression lae1 increased the production of long-chain antimicrobial peptides and also several new peptaibols. These results indicated that lae1 can promote the synthesis of long-chain peptaibol and improve the antibacterial activity of Trichoderma. And lae1 over-expression strains are potential candidate for developing the new Trichoderma biocontrol agents with peptaibols as the main component.