Study of enzymes governing fruit softening processes in strawberry (Fragaria x ananassa). Implication of pectin methylesterases and determination of the role of pectate lyases by RNA interference
Fruit maturation is a complex mechanism involving expression of many genes responsible for accumulation of organoleptic compounds but also for fruit softening. This last process, caused by cell wall depolymerization and solubilization of polysaccarides has a high commercial impact because of losses occurring at harvest, transport and retail of soft fruits such as strawberry. To determine the major factor involved in strawberry fruit softening, we focused on the molecular study of four of the main enzyme classes involved in plant cell wall degradation : endo-1,4-β-glucanases, expansins, pectin methylesterases and pectate lyases. More particularly, we determined the activity and the role of pectin methylesterases during strawberry fruit development (cv Elsanta). By analysis of RNAi transgenic strawberry fruits knocked out for pectate lyases, we also quantified the importance of these enzymes in strawberry fruit softening during the first stages of maturation.