|ISHIMARU, MEGUMI - OSAKA PREFECTURE UNIV, JA
|KOBAYASHI, SHOZO - NAT INST FRUIT TREE SCI
Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2006
Publication Date: N/A
Interpretive Summary: A critical feature of fruit ripening is the softening that occurs due to degradation of the cell wall, a sugar envelope surrounding plant cells. The cell wall imparts rigidity and structure to plants, similar to the skin and bones of animals. If cell wall degradation can be slowed down, we will be able to pick and ship fruit at a riper more delicious stage. Our research has characterized the role of several grape berry genes that we believe are involved in fruit softening. These results will help us develop ways to allow grape fruit to ripen fully, while slowing down softening. This will benefit consumers, packers and shippers by increasing shelf-life while maintaining quality during storage, shipping and marketing.
Technical Abstract: Three cDNAs, Vlexp1, Vlexp2, and Vlexp3, for expansin, which is known to be a cell-wall modification-related protein, were isolated from mature berries of the Kyoho grape, and their expression profiles and tissues were analyzed during berry development. Among the three genes, accumulation of the Vlexp3 transcript was closely related to berry softening; expressions of this gene were detected before véraison and were markedly increased at véraison (the stage of the onset of berry softening). In addition, the expression of these genes was berry-specific. Vlexp1 and Vlexp2, mRNA accumulation began at an early stage, (expantion stage), of berry development, and their expression continued to increase during ripening. These genes were also expressed in other tissues (leaves, tendrils, roots, flowers, and seeds; the Vlexp1 transcript was not detected in roots and seeds). These findings suggest that the four expansin genes are associated with cell division or expansion and berry ripening. Vlexp3, in particular, probably plays a role in grape berry softening at véraison.