title: Alcohol acyl transferase 1 links two distinct volatile pathways that produce esters and phenylpropenes in apple fruit.
abstract: Fruit accumulate a diverse set of volatiles including esters and phenylpropenes. Volatile esters are synthesised via fatty acid degradation or from amino acid precursors, with the final step being catalysed by alcohol acyl transferases (AATs). Phenylpropenes are produced as a side branch of the general phenylpropanoid pathway. Major quantitative trait loci (QTLs) on apple (Malus × domestica) linkage group (LG)2 for production of the phenylpropene estragole and volatile esters (including 2-methylbutyl acetate and hexyl acetate) both co-located with the MdAAT1 gene. MdAAT1 has previously been shown to be required for volatile ester production in apple (Plant J., 2014, https://doi.org/10.1111/tpj.12518), and here we show it is also required to produce p-hydroxycinnamyl acetates that serve as substrates for a bifunctional chavicol/eugenol synthase (MdoPhR5) in ripe apple fruit. Fruit from transgenic 'Royal Gala' MdAAT1 knockdown lines produced significantly reduced phenylpropene levels, whilst manipulation of the phenylpropanoid pathway using MdCHS (chalcone synthase) knockout and MdMYB10 over-expression lines increased phenylpropene production. Transient expression of MdAAT1, MdoPhR5 and MdoOMT1 (O-methyltransferase) genes reconstituted the apple pathway to estragole production in tobacco. AATs from ripe strawberry (SAAT1) and tomato (SlAAT1) fruit can also utilise p-coumaryl and coniferyl alcohols, indicating that ripening-related AATs are likely to link volatile ester and phenylpropene production in many different fruit.
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Yar-Khing
authors.initials: YK
authors.lastname: Yauk
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Edwige J F
authors.initials: EJF
authors.lastname: Souleyre
authors.affiliation: PFR, Private Bag 11600, Palmerston North, 4442, New Zealand.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Matich
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Xiuyin
authors.initials: X
authors.lastname: Chen
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Mindy Y
authors.initials: MY
authors.lastname: Wang
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Blue
authors.initials: B
authors.lastname: Plunkett
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Dare
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Richard V
authors.initials: RV
authors.lastname: Espley
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Sumathi
authors.initials: S
authors.lastname: Tomes
authors.affiliation: PFR, Private Bag 11600, Palmerston North, 4442, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Chagné
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand.
authors.forename: Ross G
authors.initials: RG
authors.lastname: Atkinson
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000081248:Allylbenzene Derivatives; D000840:Anisoles / Q000378:metabolism*; D004952:Esters / Q000378:metabolism; D031985:Fragaria / Q000235:genetics; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D018551:Solanum lycopersicum / Q000235:genetics; D027845:Malus / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D010636:Phenols / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D040641:Quantitative Trait Loci; D014026:Nicotiana / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D000081248:Allylbenzene Derivatives; D000840:Anisoles; D004952:Esters; D010636:Phenols; D010940:Plant Proteins; D011506:Proteins; D055549:Volatile Organic Compounds; C007633:estragole; C010559:coniferyl alcohol; D000217:Acyltransferases; C020141:flavanone synthetase; C079238:alcohol O-acetyltransferase
keywords: 
  Malus domestica
  ; alcohol acyl transferase; apple; ester; fruit; phenylpropene; volatile