Tomato GDSL1 is required for cutin deposition in the fruit cuticle.
The plant cuticle consists of cutin, a polyester of glycerol, hydroxyl, and epoxy fatty acids, covered and filled by waxes. While the biosynthesis of cutin building blocks is well documented, the mechanisms underlining their extracellular deposition remain unknown. Among the proteins extracted from dewaxed tomato (Solanum lycopersicum) peels, we identified GDSL1, a member of the GDSL esterase/acylhydrolase family of plant proteins. GDSL1 is strongly expressed in the epidermis of growing fruit. In GDSL1-silenced tomato lines, we observed a significant reduction in fruit cuticle thickness and a decrease in cutin monomer content proportional to the level of GDSL1 silencing. A significant decrease of wax load was observed only for cuticles of the severely silenced transgenic line. Fourier transform infrared (FTIR) analysis of isolated cutins revealed a reduction in cutin density in silenced lines. Indeed, FTIR-attenuated total reflectance spectroscopy and atomic force microscopy imaging showed that drastic GDSL1 silencing leads to a reduction in ester bond cross-links and to the appearance of nanopores in tomato cutins. Furthermore, immunolabeling experiments attested that GDSL1 is essentially entrapped in the cuticle proper and cuticle layer. These results suggest that GDSL1 is specifically involved in the extracellular deposition of the cutin polyester in the tomato fruit cuticle.
Unité Biopolymères, Interactions, Assemblages, Institut National de la Recherche Agronomique, F-44316 Nantes cedex 3, France.
Anne-Laure
AL
Girard
Fabien
F
Mounet
Martine
M
Lemaire-Chamley
Cédric
C
Gaillard
Khalil
K
Elmorjani
Julien
J
Vivancos
Jean-Luc
JL
Runavot
Bernard
B
Quemener
Johann
J
Petit
Véronique
V
Germain
Christophe
C
Rothan
Didier
D
Marion
Bénédicte
B
Bakan
D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics; D005638:Fruit / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020868:Gene Silencing; D018551:Solanum lycopersicum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D019441:Plant Epidermis / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D040901:Proteomics; D034622:RNA Interference; D014885:Waxes / Q000737:chemistry / Q000378:metabolism
D008563:Membrane Lipids; D010940:Plant Proteins; D014885:Waxes; C000521:cutin; D002265:Carboxylic Ester Hydrolases