title: A Feedback-Insensitive Isopropylmalate Synthase Affects Acylsugar Composition in Cultivated and Wild Tomato.
abstract: Acylsugars are insecticidal specialized metabolites produced in the glandular trichomes of plants in the Solanaceae family. In the tomato clade of the Solanum genus, acylsugars consist of aliphatic acids of different chain lengths esterified to sucrose, or less frequently to glucose. Through liquid chromatography-mass spectrometry screening of introgression lines, we previously identified a region of chromosome 8 in the Solanum pennellii LA0716 genome (IL8-1/8-1-1) that causes the cultivated tomato Solanum lycopersicum to shift from producing acylsucroses with abundant 3-methylbutanoic acid acyl chains derived from leucine metabolism to 2-methylpropanoic acid acyl chains derived from valine metabolism. We describe multiple lines of evidence implicating a trichome-expressed gene from this region as playing a role in this shift. S. lycopersicum M82 SlIPMS3 (Solyc08g014230) encodes a functional end product inhibition-insensitive version of the committing enzyme of leucine biosynthesis, isopropylmalate synthase, missing the carboxyl-terminal 160 amino acids. In contrast, the S. pennellii LA0716 IPMS3 allele found in IL8-1/8-1-1 encodes a nonfunctional truncated IPMS protein. M82 transformed with an SlIPMS3 RNA interference construct exhibited an acylsugar profile similar to that of IL8-1-1, whereas the expression of SlIPMS3 in IL8-1-1 partially restored the M82 acylsugar phenotype. These IPMS3 alleles are polymorphic in 14 S. pennellii accessions spread throughout the geographical range of occurrence for this species and are associated with acylsugars containing varying amounts of 2-methylpropanoic acid and 3-methylbutanoic acid acyl chains.
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Jing
authors.initials: J
authors.lastname: Ning
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Gaurav D
authors.identifier: http://orcid.org/0000-0002-8761-064X
authors.initials: GD
authors.lastname: Moghe
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Bryan
authors.identifier: http://orcid.org/0000-0003-4042-1160
authors.initials: B
authors.lastname: Leong
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Jeongwoon
authors.identifier: http://orcid.org/0000-0002-7102-6799
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Itai
authors.initials: I
authors.lastname: Ofner
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Christopher
authors.initials: C
authors.lastname: Adams
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: A Daniel
authors.identifier: http://orcid.org/0000-0002-7408-6690
authors.initials: AD
authors.lastname: Jones
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.).
authors.forename: Dani
authors.initials: D
authors.lastname: Zamir
authors.affiliation: Department of Biochemistry and Molecular Biology (J.N., G.D.M., B.L., Z.W., A.D.J., R.L.L.), Department of Plant Biology (J.K., R.L.L.), and Department of Chemistry (A.D.J.), Michigan State University, East Lansing, Michigan 48824;Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (I.O., D.Z.); andDepartment of Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland 20686 (C.A.) lastr@msu.edu.
authors.forename: Robert L
authors.identifier: http://orcid.org/0000-0001-6974-9587
authors.initials: RL
authors.lastname: Last
mesh_terms: D015079:2-Isopropylmalate Synthase / Q000378:metabolism*; D000215:Acylation; D000483:Alleles; D001483:Base Sequence; D002241:Carbohydrates / Q000737:chemistry; D002853:Chromatography, Liquid; D005227:Fatty Acids / Q000737:chemistry*; D007700:Kinetics; D018551:Solanum lycopersicum / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D032322:Solanum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D013395:Sucrose / Q000737:chemistry; D064201:Trichomes / Q000201:enzymology / Q000235:genetics
chemical_list: D002241:Carbohydrates; D005227:Fatty Acids; D010940:Plant Proteins; D013395:Sucrose; D015079:2-Isopropylmalate Synthase