title: Location of chlorogenic acid biosynthesis pathway and polyphenol oxidase genes in a new interspecific anchored linkage map of eggplant.
abstract: BACKGROUND
  Eggplant is a powerful source of polyphenols which seems to play a key role in the prevention of several human diseases, such as cancer and diabetes. Chlorogenic acid is the polyphenol most present in eggplant, comprising between the 70% and 90% of the total polyphenol content. Introduction of the high chlorogenic acid content of wild relatives, such as S. incanum, into eggplant varieties will be of great interest. A potential side effect of the increased level polyphenols could be a decrease on apparent quality due to browning caused by the polyphenol oxidase enzymes mediated oxidation of polyphenols. We report the development of a new interspecific S. melongena × S. incanum linkage map based on a first backcross generation (BC1) towards the cultivated S. melongena as a tool for introgressing S. incanum alleles involved in the biosynthesis of chlorogenic acid in the genetic background of S. melongena.
  
  
  RESULTS
  The interspecific genetic linkage map of eggplant developed in this work anchor the most informative previously published genetic maps of eggplant using common markers. The 91 BC1 plants of the mapping population were genotyped with 42 COSII, 99 SSRs, 88 AFLPs, 9 CAPS, 4 SNPs and one morphological polymorphic markers. Segregation marker data resulted in a map encompassing 1085 cM distributed in 12 linkage groups. Based on the syntheny with tomato, the candidate genes involved in the core chlorogenic acid synthesis pathway in eggplant (PAL, C4H, 4CL, HCT, C3'H, HQT) as well as five polyphenol oxidase (PPO1, PPO2, PPO3, PPO4, PPO5) were mapped. Except for 4CL and HCT chlorogenic acid genes were not linked. On the contrary, all PPO genes clustered together. Candidate genes important in domestication such as fruit shape (OVATE, SISUN1) and prickliness were also located.
  
  
  CONCLUSIONS
  The achievements in location of candidate genes will allow the search of favorable alleles employing marker-assisted selection in order to develop new varieties with higher chlorogenic content alongside a lower polyphenol oxidase activity. This will result into an enhanced product showing a lower fruit flesh browning with improved human health properties.
authors.forename: Pietro
authors.initials: P
authors.lastname: Gramazio
authors.forename: Jaime
authors.initials: J
authors.lastname: Prohens
authors.forename: Mariola
authors.initials: M
authors.lastname: Plazas
authors.forename: Isabel
authors.initials: I
authors.lastname: Andújar
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Herraiz
authors.forename: Elena
authors.initials: E
authors.lastname: Castillo
authors.forename: Sandra
authors.initials: S
authors.lastname: Knapp
authors.forename: Rachel S
authors.initials: RS
authors.lastname: Meyer
authors.forename: Santiago
authors.initials: S
authors.lastname: Vilanova
mesh_terms: D004156:Catechol Oxidase / Q000235:genetics* / Q000378:metabolism; D002726:Chlorogenic Acid / Q000378:metabolism*; D002874:Chromosome Mapping; D008040:Genetic Linkage; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D032322:Solanum / Q000201:enzymology* / Q000235:genetics*; D032323:Solanum melongena / Q000201:enzymology / Q000235:genetics; D026801:Synteny
chemical_list: D010940:Plant Proteins; D002726:Chlorogenic Acid; D004156:Catechol Oxidase