Regulatory mechanism of GA(3) application on grape (Vitis vinifera L.) berry size.

Gibberellin A3 (GA3) is often used as a principal growth regulator to increase plant size. Here, we applied Tween-20 (2%)-formulated GA3 (T1:40 mg/L; T2:70 mg/L) by dipping the clusters at the initial expansion phase of 'Red Globe' grape (Vitis vinifera L.) in 2018 and 2019. Tween-20 (2%) was used as a control. The results showed that GA3 significantly increased fruit cell length, cell size, diameter, and volume. The hormone levels of auxin (IAA) and zeatin (ZT) were significantly increased at 2 h (0 d) -1 d after application (DAA0-1) and remained significantly higher at DAA1 until maturity. Conversely, ABA exhibited an opposite trend. The mRNA and non-coding sequencing results yielded 436 differentially expressed mRNA (DE_mRNAs), 79 DE_lncRNAs and 17 DE_miRNAs. These genes are linked to hormone pathways like cysteine and methionine metabolism (ko00270), glutathione metabolism (ko00480) and plant hormone signal transduction (ko04075). GA3 application reduced expression of insensitive dwarf 2 (GID2, VIT_07s0129g01000), small auxin-upregulated RNA (SAUR, VIT_08s0007g03120) and 1-aminocyclopropane-1-carboxylate synthase (ACS, VIT_18s0001g08520), but increased SAUR (VIT_04s0023g00560) expression. These four genes were predicted to be negatively regulated by vvi-miR156, vvi-miR172, vvi-miR396, and vvi-miR159, corresponding to specific lncRNAs. Therefore, miRNAs could affect grape size by regulating key genes GID2, ACS and SAUR. The R2R3 MYB family member VvRAX2 (VIT_08s0007g05030) was upregulated in response to GA3 application. Overexpression of VvRAX2 in tomato transgenic lines increased fruit size in contrast to the wild type. This study provides a basis and genetic resources for elucidating the novel role of ncRNAs in fruit development.

Li WF ，Zhou Q ，Ma ZH ，Zuo CW ，Chu MY ，Mao J ，Chen BH ... -  《-》

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 ... -  《-》

GA(3) application in grapes (Vitis vinifera L.) modulates different sets of genes at cluster emergence, full bloom, and berry stage as revealed by RNA sequence-based transcriptome analysis.

Upadhyay A ，Maske S ，Jogaiah S ，Kadoo NY ，Gupta VS ... -  《-》

Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening.

Böttcher C ，Burbidge CA ，Boss PK ，Davies C ... -  《BMC PLANT BIOLOGY》

Proteomic analysis of berry-sizing effect of GA3 on seedless Vitis vinifera L.

Gibberellin (GA) is widely used in the table grape and raisin industries to enlarge the berries of seedless varieties. However, the mechanism underlying its berry-sizing effect is poorly understood. In this study, clusters of Centennial Seedless (Vitis vinifera L.) were treated with 30 ppm GA3 on day 12 after flowering, and berries were sampled at development stages I, II and III for proteomic analysis. Among the 1479 proteins detected on 2-DE maps, 19, 70 and 69 spots in stages I, II and III, respectively, showed an at least twofold difference in volume between treatments and controls. Of these, 125 proteins were successfully identified and assigned to eight functional groups, chief among them are metabolism and energy, stress response, expression regulation and cytoskeleton proteins. Stress-response proteins were predominantly down-regulated in GA3-treated berries in stages I and II, and significantly up-regulated in stage III. Up-regulation of cytoskeleton, cell-wall modification and other important proteins was found in the two latter stages of berry development. Our proteomic results and subsequent validation revealed, for the first time, the role of redox homeostasis in GA3-induced berry enlargement and markedly remodeled cellular protein expression in treated berries.

Wang Z ，Zhao F ，Zhao X ，Ge H ，Chai L ，Chen S ，Perl A ，Ma H ... -  《-》