Rhamnogalacturonase lyase gene downregulation in strawberry and its potential on mechanical fruit properties

Strawberry softening is one of the main factors that reduces fruit quality and leads to economically important losses. Textural changes during fruit ripening are mainly due to the dissolution of middle lamellae, a reduction in cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Functional studies of genes encoding pectinase enzymes, such as polygalacturonase [1], pectate lyase [2] or β-galactosidase [3] support a key role of pectin disassembly in strawberry softening. Evidence that RG-I may play an important role has been obtained from the transient silencing of RG-lyase gene in strawberry fruits [4]. Pectins are major components of fruit cell walls and are highly dynamic polysaccharides, but due to their heterogeneity, the precise relation between the structures and functions is incomplete. In this work, stable transgenic strawberry lines with a down-regulated rhamnogalacturonate lyase gene (FaRGLyase1) has been analyzed.