Chromosome-level assembly and analysis of the Thymus genome provide insights into glandular secretory trichome formation and monoterpenoid biosynthesis in thyme  

作　　者：Meiyu Sun Yanan Zhang Li Zhu Ningning Liu Hongtong Bai Guofeng Sun Jinzheng Zhang Lei Shi 

机构地区：[1]Key Laboratory of Plant Resources and Beijing Botanical Garden,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Beijing Botanical Garden,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China

出　　处：《Plant Communications》2022年第6期56-73,共18页植物通讯（英文）

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant XDA23080603).

摘　　要：Thyme has medicinal and aromatic value because of its potent antimicrobial and antioxidant properties.However,the absence of a fully sequenced thyme genome limits functional genomic studies of Chinese native thymes.Thymus quinquecostatus Celak.,which contains large amounts of bioactive monoterpenes suchas thymol and carvacrol,is an important wild medicinal and aromatic plant in China.Monoterpenoids are abundant in glandular secretory trichomes.Here,high-fidelity and chromatin conformation capture technologies were used to assemble and annotate the T.quinquecostatus genome at the chromosome level.The 13 chromosomes of T.quinquecostatus had a total length of 528.66 Mb,a contig N50 of 8.06 Mb,and a BUSCO score of 97.34%.We found that T.quinquecostatus had experienced two whole-genome duplications,with the most recent event occurring4.34 million years ago.Deep analyses of the genome,in conjunction with comparative genomic,phylogenetic,transcriptomic,and metabonomic studies,uncovered many regulatory factors and genes related to monoterpenoids and glandular secretory trichome development.Genes encoding terpene synthase(TPS),cytochrome P450 monooxygenases(CYPs),short-chain dehydrogenase/reductase(SDR),R2R3-MYB,and homeodomain-leucine zipper(HD-ZIP)IV were among those present in the T.quinquecostatus genome.Notably,Tq02G002290.1(TqTPS1)was shown to encode the terpene synthase responsible for catalyzing production of the main monoterpene product g-terpinene from geranyl diphosphate(GPP).Our study provides significant insight into the mechanisms of glandular secretory trichome formation and monoterpenoid biosynthesis in thyme.This work will facilitate the development of molecular breeding tools to enhance the production of bioactive secondary metabolites in Lamiaceae.

关 键 词：Thymus quinquecostatus chromosome-level genome phylogenetics glandular secretory trichome monoterpenoids 

分 类 号：Q943.2[生物学—植物学]