VvPL15 Is the Core Member of the Pectate Lyase Gene Family Involved in Grape Berries Ripening and Softening

The process of ripening and softening in grape begins at veraison and is closely related to the depolymerization of pectin components. A variety of enzymes are involved in pectin metabolism and one class of enzyme, pectin lyases (PLs), have been reported to play an important role in softening in many fruits; however, little information is available on the VvPL gene family in grape. In this study, 16 VvPL genes were identified in the grape genome using bioinformatics methods. Among them, VvPL5, VvPL9, and VvPL15 had the highest expression levels during grape ripening, which suggests that these genes are involved in grape ripening and softening. Furthermore, overexpression of VvPL15 affects the contents of water-soluble pectin (WSP) and acid-soluble pectin (ASP) in the leaves of Arabidopsis and significantly changes the growth of Arabidopsis plants. The relationship between VvPL15 and pectin content was further determined by antisense expression of VvPL15. In addition, we also studied the effect of VvPL15 on fruit in transgenic tomato plants, which showed that VvPL15 accelerated fruit ripening and softening. Our results indicate that VvPL15 plays an important role in grape berry softening during ripening by depolymerizing pectin.

Automated summary

The ripening and softening process in grape is associated with the depolymerization of pectin components, which is facilitated by pectin lyases (PLs). This study identified 16 VvPL genes in the grape genome, and found that VvPL5, VvPL9, and VvPL15 are highly expressed during grape ripening, indicating their involvement in grape softening. Overexpression of VvPL15 in Arabidopsis affected pectin content and plant growth, while antisense expression of VvPL15 confirmed the relationship between VvPL15 and pectin content. Additionally, transgenic tomato plants with VvPL15 showed accelerated fruit ripening and softening. Thus, VvPL15 plays a crucial role in grape berry softening by depolymerizing pectin.