Identification and characterization of the iridoid synthase involved in oleuropein biosynthesis in olive (Olea europaea) fruits

TY - JOUR

T1 - Identification and characterization of the iridoid synthase involved in oleuropein biosynthesis in olive (Olea europaea) fruits

AU - Alagna, Fiammetta

AU - Geu-Flores, Fernando

AU - Kries, Hajo

AU - Panara, Francesco

AU - Baldoni, Luciana

AU - O'Connor, Sarah E

AU - Osbourn, Anne

N1 - © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

PY - 2016/3/11

Y1 - 2016/3/11

N2 - The secoiridoids are the main class of specialized metabolites present in olive (Olea europaea L.) fruit. In particular, the secoiridoid oleuropein strongly influences olive oil quality because of its bitterness, which is a desirable trait. In addition, oleuropein possesses a wide range of pharmacological properties, including antioxidant, anti-inflammatory, and anti-cancer activities. In accordance, obtaining high oleuropein varieties is a main goal of molecular breeding programs. Here we use a transcriptomic approach to identify candidate genes belonging to the secoiridoid pathway in olive. From these candidates, we have functionally characterized the olive homologue of iridoid synthase (OeISY), an unusual terpene cyclase that couples an NAD (P)H-dependent 1,4-reduction step with a subsequent cyclization, and we provide evidence that OeISY likely generates the monoterpene scaffold of oleuropein in olive fruits. OeISY, the first pathway gene characterized for this type of secoiridoid, is a potential target for breeding programs in a high value secoiridoid-accumulating species.

AB - The secoiridoids are the main class of specialized metabolites present in olive (Olea europaea L.) fruit. In particular, the secoiridoid oleuropein strongly influences olive oil quality because of its bitterness, which is a desirable trait. In addition, oleuropein possesses a wide range of pharmacological properties, including antioxidant, anti-inflammatory, and anti-cancer activities. In accordance, obtaining high oleuropein varieties is a main goal of molecular breeding programs. Here we use a transcriptomic approach to identify candidate genes belonging to the secoiridoid pathway in olive. From these candidates, we have functionally characterized the olive homologue of iridoid synthase (OeISY), an unusual terpene cyclase that couples an NAD (P)H-dependent 1,4-reduction step with a subsequent cyclization, and we provide evidence that OeISY likely generates the monoterpene scaffold of oleuropein in olive fruits. OeISY, the first pathway gene characterized for this type of secoiridoid, is a potential target for breeding programs in a high value secoiridoid-accumulating species.

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1074/jbc.m115.701276

DO - 10.1074/jbc.m115.701276

M3 - Journal article

C2 - 26709230

SN - 0021-9258

VL - 291

SP - 5542

EP - 5554

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 11

ER -