Partial demethylation of oligogalacturonides by pectin methyl esterase 1 is required for eliciting defence responses in wild strawberry (Fragaria vesca).
In addition to the role of the cell wall as a physical barrier against pathogens, some of its constituents, such as pectin-derived oligogalacturonides (OGA), are essential components for elicitation of defence responses. To investigate how modifications of pectin alter defence responses, we expressed the fruit-specific Fragaria x ananassa pectin methyl esterase FaPE1 in the wild strawberry Fragaria vesca. Pectin from transgenic ripe fruits differed from the wild-type with regard to the degree and pattern of methyl esterification, as well as the average size of pectin polymers. Purified oligogalacturonides from the transgenic fruits showed a reduced degree of esterification compared to oligogalacturonides from wild-type fruits. This reduced esterification is necessary to elicit defence responses in strawberry. The transgenic F. vesca lines had constitutively activated pathogen defence responses, resulting in higher resistance to the necrotropic fungus Botrytis cinerea. Further studies in F. vesca and Nicotiana benthamiana leaves showed that the elicitation capacity of the oligogalacturonides is more specific than previously envisaged.
Osorio
Sonia
S
Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Málaga, Spain.
Castillejo
Cristina
C
Quesada
Miguel A
MA
Medina-Escobar
Nieves
N
Brownsey
Geoff J
GJ
Suau
Rafael
R
Heredia
Antonio
A
Botella
Miguel A
MA
Valpuesta
Victoriano
V
D020171:Botrytis / Q000502:physiology; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D031985:Fragaria / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D010368:Pectins / Q000737:chemistry / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D014574:Uronic Acids / Q000378:metabolism*
D010940:Plant Proteins; D014574:Uronic Acids; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase