Identification of miRNAs-mediated seed and stone-hardening regulatory networks and their signal pathway of GA-induced seedless berries in grapevine (V. vinifera L.).

Stone-hardening stage is crucial to the development of grape seed and berry quality. A significant body of evidence supports the important roles of MicroRNAs in grape-berry development, but their specific molecular functions during grape stone-hardening stage remain unclear. Here, a total of 161 conserved and 85 species-specific miRNAs/miRNAs* (precursor) were identified in grape berries at stone-hardening stage using Solexa sequencing. Amongst them, 30 VvmiRNAs were stone-hardening stage-specific, whereas 52 exhibited differential expression profiles during berry development, potentially participating in the modulation of berry development as verified by their expression patterns. GO and KEGG pathway analysis showed that 13 VvmiRNAs might be involved in the regulation of embryo development, another 11 in lignin and cellulose biosynthesis, and also 28 in the modulation of hormone signaling, sugar, and proline metabolism. Furthermore, the target genes for 4 novel VvmiRNAs related to berry development were validated using RNA Ligase-Mediated (RLM)-RACE and Poly(A) Polymerase-Mediated (PPM)-RACE methods, and their cleavage mainly occurred at the 9th-11th sites from the 5' ends of miRNAs at their binding regions. In view of the regulatory roles of GA in seed embryo development and stone-hardening in grape, we investigated the expression modes of VvmiRNAs and their target genes during GA-induced grape seedless-berry development, and we validated that GA induced the expression of VvmiR31-3p and VvmiR8-5p to negatively regulate the expression levels of CAFFEOYL COENZYME A-3-O-METHYLTRANSFERASE (VvCCoAOMT), and DDB1-CUL4 ASSOCIATED FACTOR1 (VvDCAF1). The series of changes might repress grape stone hardening and embryo development, which might be a potential key molecular mechanism in GA-induced grape seedless-berry development. Finally, a schematic model of miRNA-mediated grape seed and stone-hardening development was proposed. This work identified 30 stone-hardening stage-specific VvmiRNAs and 52 significant differential expression ones, and preliminary interpreted the potential molecular mechanism of GA-induced grape parthenocarpy. GA negatively manipulate the expression of VvCCoAOMT and VvDCAF1 by up-regulation the expression of VvmiR31-3p and VvmiR8-5p, thereby repressing seed stone and embryo development to produce grape seedless berries.

Wang P ，Xuan X ，Su Z ，Wang W ，Abdelrahman M ，Jiu S ，Zhang X ，Liu Z ，Wang X ，Wang C ，Fang J ... -  《BMC PLANT BIOLOGY》

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》

Characterization of VvmiR166s-Target Modules and Their Interaction Pathways in Modulation of Gibberellic-Acid-Induced Grape Seedless Berries.

Bai Y ，Wang Z ，Luo L ，Xuan X ，Tang W ，Qu Z ，Dong T ，Qi Z ，Yu M ，Wu W ，Fang J ，Wang C ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

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 ... -  《-》

VvmiR160s/VvARFs interaction and their spatio-temporal expression/cleavage products during GA-induced grape parthenocarpy.

Zhang W ，Abdelrahman M ，Jiu S ，Guan L ，Han J ，Zheng T ，Jia H ，Song C ，Fang J ，Wang C ... -  《BMC PLANT BIOLOGY》