Demethylation of oligogalacturonides by FaPE1 in the fruits of the wild strawberry Fragaria vesca triggers metabolic and transcriptional changes associated with defence and development of the fruit

Abstract

Ectopic expression of the strawberry (Fragaria×ananassa) gene FaPE1 encoding pectin methyl esterase produced in the wild species Fragaria vesca partially demethylated oligogalacturonides (OGAs), which conferred partial resistance of ripe fruits to the fungus Botrytis cinerea. Analyses of metabolic and transcriptional changes in the receptacle of the transgenic fruits revealed channelling of metabolites to aspartate and aromatic amino acids as well as phenolics, flavanones, and sesquiterpenoids, which was in parallel with the increased expression of some genes related to plant defence. The results illustrate the changes associated with resistance to B. cinerea in the transgenic F. vesca. These changes were accompanied by a significant decrease in the auxin content of the receptacle of the ripe fruits of transgenic F. vesca, and enhanced expression of some auxin-repressed genes. The role of these OGAs in fruit development was revealed by the larger size of the ripe fruits in transgenic F. vesca. When taken together these results show that in cultivated F. ananassa FaPE1 participates in the de-esterification of pectins and the generation of partially demethylated OGAs, which might reinforce the plant defence system and play an active role in fruit development.

Tomato Fruit Photosynthesis Is Seemingly Unimportant in Primary Metabolism and Ripening But Plays a Considerable Role in Seed Development

“…Secondary metabolites were measured according to Tohge and Fernie (2010). IAA was determined exactly as defined by Osorio et al (2011).…”

Cell wall integrity

“…The de-esterification of OGs by overexpression of a fruit-specific PME in wild strawberry was required to elicit defense-related gene expression and induce plant resistance to B. cinerea. 82,83 Consistent with this, chemical methylesterification of OGs greatly diminishes their ability to elicit biological responses. 84,85 Treatment with OGs can protect wheat, a grass species with low pectin contents, against Blumeria graminis.…”

Conserved Changes in the Dynamics of Metabolic Processes during Fruit Development and Ripening across Species

“…production of volatile compounds providing the characteristic aroma; Carrari and Fernie, 2006;Howard and Wildman, 2007;Fait et al, 2008;Zhang et al, 2011;Wahyuni et al, 2013). These transformations are the result of dynamic processes that involve a complex series of molecular and biochemical changes under genetic regulation and/or in response to environmental perturbations (Giovannoni, 2004;Do et al, 2010;Page et al, 2010;Klee and Giovannoni, 2011;Osorio et al, 2011aOsorio et al, , 2011bOsorio et al, , 2013aPan et al, 2012;Tieman et al, 2012).…”

“…To better understand fruit development and ripening mechanisms, numerous studies have focused on measuring transcript and metabolite levels in climacteric fruits, such as tomato (Alba et al, 2005;Vriezen et al, 2008;Enfissi et al, 2010;Karlova et al, 2011;Osorio et al, 2011a) and peach (Borsani et al, 2009;Zhang et al, 2010;Lombardo et al, 2011;Li et al, 2012), and in nonclimacteric fruits, such as strawberry (Aharoni and O'Connell, 2002;Fait et al, 2008;Bombarely et al, 2010;Osorio et al, 2011b;Zhang et al, 2011), pepper (Kim et al, 2008;Lee et al, 2010;Osorio et al, 2012;Liu et al, 2013;Wahyuni et al, 2013), and grape Grimplet et al, 2007). These studies have been complemented by the investigation of transcriptomics, proteomics, and metabolomics data in the three dominant ripening mutants of tomato, ripening-inhibitor (rin), nonripening (nor), and never-ripe (Nr), along the developmental and ripening periods.…”

“…These studies have been complemented by the investigation of transcriptomics, proteomics, and metabolomics data in the three dominant ripening mutants of tomato, ripening-inhibitor (rin), nonripening (nor), and never-ripe (Nr), along the developmental and ripening periods. While integration of genomics, transcriptomics, and metabolomics data during fruit development and ripening can give important insight into gene regulatory and metabolic events associated with these processes in a single species Grimplet et al, 2007;Enfissi et al, 2010;Zamboni et al, 2010;Osorio et al, 2011aOsorio et al, , 2011bOsorio et al, , 2012Rohrmann et al, 2011), identifying the metabolic functions that are similarly regulated across different species has not yet been attempted.…”