Functional characterization and developmental expression profiling of gibberellin signalling components in Vitis vinifera.

Gibberellins (GAs) regulate numerous developmental processes in grapevine (Vitis vinifera) such as rachis elongation, fruit set, and fruitlet abscission. The ability of GA to promote berry enlargement has led to its indispensable use in the sternospermocarpic ('seedless') table grape industry worldwide. However, apart from VvGAI1 (VvDELLA1), which regulates internode elongation and fruitfulness, but not berry size of seeded cultivars, little was known about GA signalling in grapevine. We have identified and characterized two additional DELLAs (VvDELLA2 and VvDELLA3), two GA receptors (VvGID1a and VvGID1b), and two GA-specific F-box proteins (VvSLY1a and VvSLY1b), in cv. Thompson seedless. With the exception of VvDELLA3-VvGID1b, all VvDELLAs interacted with the VvGID1s in a GA-dependent manner in yeast two-hybrid assays. Additionally, expression of these grape genes in corresponding Arabidopsis mutants confirmed their functions in planta. Spatiotemporal analysis of VvDELLAs showed that both VvDELLA1 and VvDELLA2 are abundant in most tissues, except in developing fruit where VvDELLA2 is uniquely expressed at high levels, suggesting a key role in fruit development. Our results further suggest that differential organ responses to exogenous GA depend on the levels of VvDELLA proteins and endogenous bioactive GAs. Understanding this interaction will allow better manipulation of GA signalling in grapevine.

Acheampong AK ，Hu J ，Rotman A ，Zheng C ，Halaly T ，Takebayashi Y ，Jikumaru Y ，Kamiya Y ，Lichter A ，Sun TP ，Or E ... -  《-》

Genome-wide identification and characterization of gibberellin metabolic and signal transduction (GA MST) pathway mediating seed and berry development (SBD) in grape (Vitis vinifera L.).

Wang W ，Bai Y ，Koilkonda P ，Guan L ，Zhuge Y ，Wang X ，Liu Z ，Jia H ，Wang C ，Fang J ... -  《BMC PLANT BIOLOGY》

RNA sequencing reveals high resolution expression change of major plant hormone pathway genes after young seedless grape berries treated with gibberellin.

Seedless varieties are of particular importance to the table-grape and raisin industries. Gibberellin (GA) application is widely used in the early stages of seedless berry development to increase berry size and economic value. However, the underlying mechanism of GA induction of berry enlargement is not well understood. Here, RNA-sequencing analysis of 'Centennial Seedless' (Vitis vinifera L.) berries treated with GA3 12 days after flowering is reported. Pair-wise comparison of GA3-treated and control samples detected 165, 444, 463 genes with an over two-fold change in expression 1, 3, and 7 days after GA3 treatment, respectively. The number of differentially expressed genes increased with time after GA3 treatment, and the differential expression was dominated by downregulation. Significantly modulated expression included genes encoding synthesis and catabolism to manage plant hormone homeostasis, hormone transporters, receptors and key components in signaling pathways; exogenous GA3 induced multipoint cross talk with auxin, cytokinin, brassinosteroid, ABA and ethylene. The temporal gene-expression patterns of cell-wall-modification enzymes, cytoskeleton and membrane components and transporters revealed a pivotal role for cell-wall-relaxation genes in GA3-induced berry enlargement. Our results provide the first sequential transcriptomic atlas of exogenous GA3-induced berry enlargement and reveal the complexity of GA3's effect on berry sizing.

Chai L ，Li Y ，Chen S ，Perl A ，Zhao F ，Ma H ... -  《-》

Gibberellin metabolism in Vitis vinifera L. during bloom and fruit-set: functional characterization and evolution of grapevine gibberellin oxidases.

Giacomelli L ，Rota-Stabelli O ，Masuero D ，Acheampong AK ，Moretto M ，Caputi L ，Vrhovsek U ，Moser C ... -  《-》

Interaction of VvDELLA2 and VvCEB1 Mediates Expression of Expansion-Related Gene during GA-Induced Enlargement of Grape Fruit.

Liu Z ，Wang Y ，Guan P ，Hu J ，Sun L ... -  《-》