Phylogenomic Mining of the Mints Reveals Multiple Mechanisms Contributing to the Evolution of Chemical Diversity in Lamiaceae  

作　　者：Mint Evolutionary Genomics Consortium 

机构地区：[1]Department of Biochemistry, Purdue University, West Lafayette, IN 47907-2063, USA [2]Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA [3]Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA [4]The John Innes Centre, Department of Biological Chemistry, Norwich NR4 7UH, UK [5]Department of Biology, University of Florida, Gainesville, FL 32611, USA

出　　处：《Molecular Plant》2018年第8期1084-1096,共13页分子植物（英文版）

基　　金：Funds for this study were provided by a grant to C.R.B., N.D., S.E.O., D.S., and P.S. from the National Science Foundation Plant Genome Research Program （IOS-1444499） and from Hatch Funds （MICL02431） to C.R.B.

摘　　要：The evolution of chemical complexity has been a major driver of plant diversification, with novel compounds serving as key innovations. The species-rich mint family （Lamiaceae） produces an enormous variety of compounds that act as attractants and defense molecules in nature and are used widely by humans as flavor additives, fragrances, and anti-herbivory agents. To elucidate the mechanisms by which such diversity evolved, we combined leaf transcriptome data from 48 Lamiaceae species and four outgroups with a robust phylogeny and chemical analyses of three terpenoid classes （monoterpenes, sesquiterpenes, and iridoids） that share and compete for precursors. Our integrated chemical-genomic-phylogenetic approach revealed that： （1） gene family expansion rather than increased enzyme promiscuity of terpene synthases is correlated with mono- and sesquiterpene diversity; （2） differential expression of core genes within the iri- doid biosynthetic pathway is associated with iridoid presence/absence; （3） generally, production of iridoids and canonical monoterpenes appears to be inversely correlated; and （4） iridoid biosynthesis is significantly associated with expression of geraniol synthase, which diverts metabolic flux away from canonical mono- terpenes, suggesting that competition for common precursors can be a central control point in specialized metabolism. These results suggest that multiple mechanisms contributed to the evolution of chemodiversity in this economically important family.The evolution of chemical complexity has been a major driver of plant diversification, with novel compounds serving as key innovations. The species-rich mint family （Lamiaceae） produces an enormous variety of compounds that act as attractants and defense molecules in nature and are used widely by humans as flavor additives, fragrances, and anti-herbivory agents. To elucidate the mechanisms by which such diversity evolved, we combined leaf transcriptome data from 48 Lamiaceae species and four outgroups with a robust phylogeny and chemical analyses of three terpenoid classes （monoterpenes, sesquiterpenes, and iridoids） that share and compete for precursors. Our integrated chemical-genomic-phylogenetic approach revealed that： （1） gene family expansion rather than increased enzyme promiscuity of terpene synthases is correlated with mono- and sesquiterpene diversity; （2） differential expression of core genes within the iri- doid biosynthetic pathway is associated with iridoid presence/absence; （3） generally, production of iridoids and canonical monoterpenes appears to be inversely correlated; and （4） iridoid biosynthesis is significantly associated with expression of geraniol synthase, which diverts metabolic flux away from canonical mono- terpenes, suggesting that competition for common precursors can be a central control point in specialized metabolism. These results suggest that multiple mechanisms contributed to the evolution of chemodiversity in this economically important family.

关 键 词：chemodiversity EVOLUTION TERPENE IRIDOID 

分 类 号：TS974.1[轻工技术与工程] O65[理学—分析化学]