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This research aims to decode the genetic mechanisms behind terpenoid biosynthesis in Mosla chinensis, a valuable medicinal plant.

June 20, 2026Open Access

Chromosome-level genome of Mosla chinensis from alpine ecotype provides insights into terpenoid biosynthesis and germplasm exploration

ZYZong-Xia YuLushan Botanical Garden HWHaifeng WangWenzhou University RLRuo LvLushan Botanical Garden

Key Points

This research aims to decode the genetic mechanisms behind terpenoid biosynthesis in Mosla chinensis, a valuable medicinal plant.
Assembled chromosome-scale genome of Mosla chinensis using SMRT sequencing and Hi-C technologies.
Conducted multi-tissue metabolomics to identify terpenoid biosynthesis hotspots in flowers and leaves.
Performed functional validation of key enzymes involved in terpenoid metabolism.
The genome assembly resulted in 444.26 Mb with 99.99% accuracy across 9 pseudochromosomes.
Metabolic engineering enhanced γ-terpinene yield 3.45-fold to 5.09 mg/L, demonstrating the genetic potential for increased terpene production.
Identified 61 biosynthetic gene clusters, with significant findings related to terpenoid metabolism and syntenic retention of specialized genes.

Abstract

Mosla chinensis is a high-value medicinal plant with scarce genomic resources for precision breeding. Here, we present the first chromosome-scale genome of an alpine ecotype (Baiyunjian Reserve, 1,611 m above sea level) assembled via SMRT sequencing and Hi-C technologies. 93.46% of sequences were anchored to 9 pseudochromosomes with 99.99% accuracy, resulting in the assembly of the 444.26 Mb genome (contig N50 = 41.38 Mb; 98.7% BUSCO). High proportion of repetitive sequences (56.90%) and species-specific genome duplication revealed the species-specific adaptations of this ecotype. Multi-tissue metabolomics identified flowers and leaves as biosynthetic hotspots for terpenoids especially γ-terpinene, thymol and carvacrol. Integrated with transcriptomics pinpointed MchTPS4 as the plastid-localized γ-terpinene synthase, while phylogenetic mining identified cytochrome P450 MchCYPs (MCH03g18750) and dehydrogenases MchSDRs (MCH04g17930/14560) as potential downstream enzymes. Functional validation confirmed that MchTPS4 was a monoterpene synthase while MchTPS2, MchTPS7, MchTPS9–11 were sesquiterpene synthases. Furthermore, metabolic engineering boosted the yield of γ-terpinene 3.45-fold to 5.09 mg/L. Biosynthetic gene clusters (BGCs) analyses uncovered 61 clusters with 11 associated with terpenoid metabolism. MchTPS2 co-localized in cluster 6 with two MchCYPs (MCH01g19200; MCH01g19220). Syntenic analysis revealed that MchTPS2 evolved as a single-copy, whereas MCH01g19200 underwent tandem duplication from M. chinensis to Salvia divinorum and S. hispanica . Phylogenomic analysis resolved M. chinensis as the sister species of Perilla frutescens (100% BS), diverging ~12.7 Mya in the mid-Miocene. Comparative genomics revealed a species-specific whole-genome duplication event post-dating divergence from Scutellaria baicalensis , driving syntenic retention of specialized metabolic genes. This study decodes the genetic basis of terpenoid biosynthesis in an extremophyte, providing resources for molecular breeding of traditional Chinese medical plant “ Xiangru ” and insights into Lamiaceae metabolic evolution.

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