title: In vitro reconstruction and analysis of evolutionary variation of the tomato acylsucrose metabolic network.
abstract: Plant glandular secreting trichomes are epidermal protuberances that produce structurally diverse specialized metabolites, including medically important compounds. Trichomes of many plants in the nightshade family (Solanaceae) produce O-acylsugars, and in cultivated and wild tomatoes these are mixtures of aliphatic esters of sucrose and glucose of varying structures and quantities documented to contribute to insect defense. We characterized the first two enzymes of acylsucrose biosynthesis in the cultivated tomato Solanum lycopersicum. These are type I/IV trichome-expressed BAHD acyltransferases encoded by Solyc12g006330--or S. lycopersicum acylsucrose acyltransferase 1 (Sl-ASAT1)--and Solyc04g012020 (Sl-ASAT2). These enzymes were used--in concert with two previously identified BAHD acyltransferases--to reconstruct the entire cultivated tomato acylsucrose biosynthetic pathway in vitro using sucrose and acyl-CoA substrates. Comparative genomics and biochemical analysis of ASAT enzymes were combined with in vitro mutagenesis to identify amino acids that influence CoA ester substrate specificity and contribute to differences in types of acylsucroses that accumulate in cultivated and wild tomato species. This work demonstrates the feasibility of the metabolic engineering of these insecticidal metabolites in plants and microbes.
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824;
authors.forename: Pengxiang
authors.initials: P
authors.lastname: Fan
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824;
authors.forename: Abigail M
authors.initials: AM
authors.lastname: Miller
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824;
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Schilmiller
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824;
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel;
authors.forename: Itai
authors.initials: I
authors.lastname: Ofner
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824; Department of Chemistry, Michigan State University, East Lansing, MI 48824;
authors.forename: A Daniel
authors.initials: AD
authors.lastname: Jones
authors.affiliation: The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel;
authors.forename: Dani
authors.initials: D
authors.lastname: Zamir
authors.affiliation: Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824; Department of Plant Biology, Michigan State University, East Lansing, MI 48824 lastr@msu.edu.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Last
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000215:Acylation; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D000596:Amino Acids / Q000378:metabolism; D005075:Biological Evolution; D018551:Solanum lycopersicum / Q000201:enzymology / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D009928:Organ Specificity; D010940:Plant Proteins / Q000378:metabolism; D011110:Polymorphism, Genetic; D013379:Substrate Specificity; D013395:Sucrose / Q000737:chemistry / Q000378:metabolism*; D064201:Trichomes / Q000201:enzymology
chemical_list: D000214:Acyl Coenzyme A; D000596:Amino Acids; D010940:Plant Proteins; D013395:Sucrose; D000217:Acyltransferases
keywords: Solanum; acylsugar; genotype to phenotype; glandular trichomes; specialized metabolism