Striking natural diversity in glandular trichome acylsugar composition is shaped by variation at the Acyltransferase2 locus in the wild tomato Solanum habrochaites.
Acylsugars are polyesters of short- to medium-length acyl chains on sucrose or glucose backbones that are produced in secretory glandular trichomes of many solanaceous plants, including cultivated tomato (Solanum lycopersicum). Despite their roles in biotic stress adaptation and their wide taxonomic distribution, there is relatively little information about the diversity of these compounds and the genes responsible for their biosynthesis. In this study, acylsugar diversity was assessed for 80 accessions of the wild tomato species Solanum habrochaites from throughout the Andes Mountains. Trichome metabolites were analyzed by liquid chromatography-time of flight-mass spectrometry, revealing the presence of at least 34 structurally diverse acylsucroses and two acylglucoses. Distinct phenotypic classes were discovered that varied based on the presence of glucose or sucrose, the numbers and lengths of acyl chains, and the relative total amounts of acylsugars. The presence or absence of an acetyl chain on the acylsucrose hexose ring caused clustering of the accessions into two main groups. Analysis of the Acyltransferase2 gene (the apparent ortholog of Solyc01g105580) revealed differences in enzyme activity and gene expression correlated with polymorphism in S. habrochaites accessions that varied in acylsucrose acetylation. These results are consistent with the hypothesis that glandular trichome acylsugar acetylation is under selective pressure in some populations of S. habrochaites and that the gene mutates to inactivity in the absence of selection.
Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA.
Jeongwoon
J
Kim
Kiyoon
K
Kang
Eliana
E
Gonzales-Vigil
Feng
F
Shi
A Daniel
AD
Jones
Cornelius S
CS
Barry
Robert L
RL
Last
D000215:Acylation; D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D002241:Carbohydrates / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D060146:Ecotype; D004952:Esters / Q000378:metabolism; D019143:Evolution, Molecular; D005227:Fatty Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D056426:Genetic Loci / Q000235:genetics*; D014644:Genetic Variation; D005843:Geography; D005947:Glucose / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D032322:Solanum / Q000033:anatomy & histology* / Q000201:enzymology / Q000235:genetics*; D013020:South America; D013395:Sucrose / Q000378:metabolism
D002241:Carbohydrates; D004952:Esters; D005227:Fatty Acids; D012333:RNA, Messenger; D013395:Sucrose; D000217:Acyltransferases; D005947:Glucose