Proposed models of action for the candidate genes identified. A) The putative pathways for Lactones and Esters biosynthesis. The δ- and γ-lactones and esters produced (numbered according to Additional file 1: Figure S1) have different alkyl groups at R6, R5, and R10, respectively. C6 and C9 are indicated below the aldehydes and alcohols, which means that the compounds can have six or nine carbons. Please note that different enzymes use free fatty acid or are activated with different groups (CoA, Acyl carrier protein or lipidic group), but must be activated with a CoA group to enter β-oxidation. B) Ethanol and Ethyl acetate production. The Acetyl-CoA produced can also be added to the pool that is used to synthesize the numbered esters (according to Additional file 1: Figure S1). C) The route for Benzenacetaldehyde biosynthesis in melon (and proposed for peach) and tomato, left and right, respectively. For the three routes (A, B, and C), the enzymes codified by the candidate genes proposed are indicated in red. D) The ID of the candidate gene that is proposed for each enzyme. Enzyme abbreviations: FAD, Fatty acid desaturase; FAE, Fatty acid Epoxydase; CYP, Cytochrome P450; PXG, Peroxygenase; FAH, Fatty acid Hydroxylase; LOX, Lipoxygenase; HPL, hydroperoxide lyase; ADH, alcohol dehydrogenase; AAT, Alcohol Acyl Transferase; PDC, Pyr decarboxylase; ALDH, Aldehyde dehydrogenase; ArAT, Aromatic aminoacid Aminotransferase; ArAD, Aromatic amino acid decarboxylase. Compound abbreviations: 2-P-Glycerate, 2-Phospho Glycerate; PEP, Phosphoenol Pyr; Pyr, Pyruvate; AA, Acetaldehyde; Phe, Phenylalanine; Glu, Glutamate.