Regulates Fruit Set and Induces Parthenocarpy by Enhancing GA Content.

Fruit set and development occur following successful fertilization. Parthenocarpy, a valuable trait in some self-incompatible species, produces seedless fruit without fertilization. Gibberellin (GA) is a crucial hormone in fruit-set regulation and development. While investigating the development of parthenocarpy in pear ( Rehd.), we determined that GA 20-oxidases (GA20ox) may play key roles in seedless pear fruit development. Sequence analysis revealed three genes: , and . We analyzed the expression patterns of candidate genes and found that levels significantly changed in pollinated fruits. Tissue-specific expression assays revealed that is highly expressed in young fruit and leaves. Subcellular localization assays showed it was located in the cytoplasm, nucleus, and plasma membrane. Overexpressed tomato plants were taller and had longer hypocotyls and internodes, and the emasculated flowers produced parthenocarpic fruit. In pear, the transient overexpression of promoted fruit development and delayed the drop of nonpollinated fruit. Furthermore, the fruit of overexpressing tomato and transient overexpressing pear had increased GA (but not GA and GA) contents. This result provided evidence that was necessary for GA-dependent pear fruit development. Our study revealed that altered the GA biosynthetic pathway and enhanced GA synthesis, thereby promoting fruit set and parthenocarpic fruit development.