title: Metabolomics of dates (Phoenix dactylifera) reveals a highly dynamic ripening process accounting for major variation in fruit composition.
abstract: BACKGROUND
  Dates are tropical fruits with appreciable nutritional value. Previous attempts at global metabolic characterization of the date metabolome were constrained by small sample size and limited geographical sampling. In this study, two independent large cohorts of mature dates exhibiting substantial diversity in origin, varieties and fruit processing conditions were measured by metabolomics techniques in order to identify major determinants of the fruit metabolome.
  
  
  RESULTS
  Multivariate analysis revealed a first principal component (PC1) significantly associated with the dates' countries of production. The availability of a smaller dataset featuring immature dates from different development stages served to build a model of the ripening process in dates, which helped reveal a strong ripening signature in PC1. Analysis revealed enrichment in the dry type of dates amongst fruits with early ripening profiles at one end of PC1 as oppose to an overrepresentation of the soft type of dates with late ripening profiles at the other end of PC1. Dry dates are typical to the North African region whilst soft dates are more popular in the Gulf region, which partly explains the observed association between PC1 and geography. Analysis of the loading values, expressing metabolite correlation levels with PC1, revealed enrichment patterns of a comprehensive range of metabolite classes along PC1. Three distinct metabolic phases corresponding to known stages of date ripening were observed: An early phase enriched in regulatory hormones, amines and polyamines, energy production, tannins, sucrose and anti-oxidant activity, a second phase with on-going phenylpropanoid secondary metabolism, gene expression and phospholipid metabolism and a late phase with marked sugar dehydration activity and degradation reactions leading to increased volatile synthesis.
  
  
  CONCLUSIONS
  These data indicate the importance of date ripening as a main driver of variation in the date metabolome responsible for their diverse nutritional and economical values. The biochemistry of the ripening process in dates is consistent with other fruits but natural dryness may prevent degenerative senescence in dates following ripening. Based on the finding that mature dates present varying extents of ripening, our survey of the date metabolome essentially revealed snapshots of interchanging metabolic states during ripening empowering an in-depth characterization of underlying biology.
authors.affiliation: Department of Physiology and Biophysics, Weill Cornell Medical College, Qatar Foundation - Education City, PO Box 24144, Doha, Qatar. ild2003@qatar-med.cornell.edu.
authors.forename: Ilhame
authors.initials: I
authors.lastname: Diboun
authors.affiliation: Department of Physiology and Biophysics, Weill Cornell Medical College, Qatar Foundation - Education City, PO Box 24144, Doha, Qatar. swm2004@qatar-med.cornell.edu.
authors.forename: Sweety
authors.initials: S
authors.lastname: Mathew
authors.affiliation: Genomics Laboratory, Weill Cornell Medical College, Doha, Qatar. m.alrayyashi@googlemail.com.
authors.forename: Maryam
authors.initials: M
authors.lastname: Al-Rayyashi
authors.affiliation: Life sciences research division, ADLQ, Doha, Qatar. melrayess@adlqatar.qa.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Elrayess
authors.affiliation: Genomics Laboratory, Weill Cornell Medical College, Doha, Qatar. mft2002@qatar-med.cornell.edu.
authors.forename: Maria
authors.initials: M
authors.lastname: Torres
authors.affiliation: Department of Physiology and Biophysics, Weill Cornell Medical College, Qatar Foundation - Education City, PO Box 24144, Doha, Qatar. amh2025@qatar-med.cornell.edu.
authors.forename: Anna
authors.initials: A
authors.lastname: Halama
authors.affiliation: MetaSysX GmbH, Potsdam, Germany. meret@metasysx.eu.
authors.forename: Michaël
authors.initials: M
authors.lastname: Méret
authors.affiliation: Metabolon, Inc., Durham, USA. RMohney@metabolon.com.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Mohney
authors.affiliation: Metabolon, Inc., Durham, USA. EKaroly@metabolon.com.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Karoly
authors.affiliation: Genomics Laboratory, Weill Cornell Medical College, Doha, Qatar. jom2042@qatar-med.cornell.edu.|Department of Genetic Medicine, Weill Cornell Medical College, Doha, Qatar. jom2042@qatar-med.cornell.edu.
authors.forename: Joel
authors.initials: J
authors.lastname: Malek
authors.affiliation: Department of Physiology and Biophysics, Weill Cornell Medical College, Qatar Foundation - Education City, PO Box 24144, Doha, Qatar. jom2042@qatar-med.cornell.edu.
authors.forename: Karsten
authors.initials: K
authors.lastname: Suhre
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005638:Fruit / Q000254:growth & development* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D055442:Metabolome; D055432:Metabolomics; D065749:Phoeniceae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D014416:Tunisia
chemical_list: D010940:Plant Proteins