Article

Role of petal-specific orcinol O-methyltransferases in the evolution of rose scent.

Laboratoire Reproduction et Développement des Plantes, Unité Mixte de Recherche 5667 Centre National de la Recherche Scientifique, IFR128 Biosciences Lyon-Gerland, France.
Plant physiology (impact factor: 6.53). 02/2006; 140(1):18-29. DOI:10.1104/pp.105.070961
Source: PubMed

ABSTRACT Orcinol O-methyltransferase (OOMT) 1 and 2 catalyze the last two steps of the biosynthetic pathway leading to the phenolic methyl ether 3,5-dimethoxytoluene (DMT), the major scent compound of many rose (Rosa x hybrida) varieties. Modern roses are descended from both European and Chinese species, the latter being producers of phenolic methyl ethers but not the former. Here we investigated why phenolic methyl ether production occurs in some but not all rose varieties. In DMT-producing varieties, OOMTs were shown to be localized specifically in the petal, predominantly in the adaxial epidermal cells. In these cells, OOMTs become increasingly associated with membranes during petal development, suggesting that the scent biosynthesis pathway catalyzed by these enzymes may be directly linked to the cells' secretory machinery. OOMT gene sequences were detected in two non-DMT-producing rose species of European origin, but no mRNA transcripts were detected, and these varieties lacked both OOMT protein and enzyme activity. These data indicate that up-regulation of OOMT gene expression may have been a critical step in the evolution of scent production in roses.

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Keywords

adaxial epidermal cells
 
biosynthetic pathway
 
critical step
 
DMT
 
DMT-producing varieties
 
enzyme activity
 
major scent compound
 
mRNA transcripts
 
non-DMT-producing
 
OOMT gene expression
 
OOMT protein
 
petal development
 
phenolic methyl ether 3,5-dimethoxytoluene
 
phenolic methyl ether production
 
phenolic methyl ethers
 
Rosa x hybrida
 
rose varieties
 
scent biosynthesis pathway catalyzed
 
scent production
 
varieties