UC Berkeley

Industrial cash crop tea is a cherished drink for its bioactive components like terpenoids and flavonoids shaping its flavor and health benefits. Trichoderma species are potent biocontrol agents and plant growth regulators, with unexplored potential in modulation of C. sinensis terpenoid biosynthesis. Genome sequencing of a tea root-associated Trichoderma sp. strain AM6 revealed a genome size of 39.91 Mbp, comprising 446 contigs organized into 406 scaffolds, with 98.8 % completeness. Single scaffold mitochondrial genome assembly of 34,430 bp in length with a GC content of 28.03 % encodes a total of 49 genes including 27 tRNA, 2 rRNA, and 20 protein-coding genes. Metabolic pathway analysis indicates exclusive reliance on the mevalonate pathway for terpenoid biosynthesis in Trichoderma, unlike C. sinensis, which utilizes both the mevalonate and non-mevalonate (MEP/DOXP) pathways. Untargeted LC-ESI-MS/MS analysis of Trichoderma identified 11,841 secondary metabolites, including 34 monoterpenoids, 72-diterpenoids, and 76-sesquiterpenoids, emphasizing its metabolic diversity. Comparative phylogenomic study positioned it as a phylogenetically distinct species with unique adaptive traits. Untargeted GC-MS shows high volatile abundance from microbial consortia (T5) followed by only Trichoderma treatment (T2) compared to control (T1). Terpenoid transcripts of C. sinensis from the plant-microbe consortium assembly sets illuminate upregulation of genes assigned to 3-hydroxy-3-methylglutaryl-Co-A reductase (HMGCR) and downregulation of genes assigned to 1-Deoxy-D-xylulose-5-phosphate (DXS), indicating metabolic shift towards more mevalonate pathway activity influenced by this novel Trichoderma strain itself and in combination with other tea root-associated microbes.