title: Deciphering gamma-decalactone biosynthesis in strawberry fruit using a combination of genetic mapping, RNA-Seq and eQTL analyses.
abstract: BACKGROUND
  Understanding the basis for volatile organic compound (VOC) biosynthesis and regulation is of great importance for the genetic improvement of fruit flavor. Lactones constitute an essential group of fatty acid-derived VOCs conferring peach-like aroma to a number of fruits including peach, plum, pineapple and strawberry. Early studies on lactone biosynthesis suggest that several enzymatic pathways could be responsible for the diversity of lactones, but detailed information on them remained elusive. In this study, we have integrated genetic mapping and genome-wide transcriptome analysis to investigate the molecular basis of natural variation in γ-decalactone content in strawberry fruit.
  
  
  RESULTS
  As a result, the fatty acid desaturase FaFAD1 was identified as the gene underlying the locus at LGIII-2 that controls γ-decalactone production in ripening fruit. The FaFAD1 gene is specifically expressed in ripe fruits and its expression fully correlates with the presence of γ-decalactone in all 95 individuals of the mapping population. In addition, we show that the level of expression of FaFAH1, with similarity to cytochrome p450 hydroxylases, significantly correlates with the content of γ-decalactone in the mapping population. The analysis of expression quantitative trait loci (eQTL) suggests that the product of this gene also has a regulatory role in the biosynthetic pathway of lactones.
  
  
  CONCLUSIONS
  Altogether, this study provides mechanistic information of how the production of γ-decalactone is naturally controlled in strawberry, and proposes enzymatic activities necessary for the formation of this VOC in plants.
authors.forename: José F
authors.initials: JF
authors.lastname: Sánchez-Sevilla
authors.forename: Eduardo
authors.initials: E
authors.lastname: Cruz-Rus
authors.forename: Victoriano
authors.initials: V
authors.lastname: Valpuesta
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Botella
authors.affiliation: Instituto Andaluz de Investigación y Formación Agraria y Pesquera, IFAPA-Centro de Churriana, Cortijo de la Cruz s/n, 29140 Málaga, Spain. iraida.amaya@juntadeandalucia.es.
authors.forename: Iraida
authors.initials: I
authors.lastname: Amaya
mesh_terms: D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D044943:Fatty Acid Desaturases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D031985:Fragaria / Q000235:genetics*; D005638:Fruit / Q000235:genetics; D018745:Genome, Plant; D007783:Lactones / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D040641:Quantitative Trait Loci; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D017386:Sequence Homology, Amino Acid; D015854:Up-Regulation / Q000235:genetics
chemical_list: D007783:Lactones; D010940:Plant Proteins; C109757:decan-4-olide; D044943:Fatty Acid Desaturases
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