College of Horticulture, Nanjing Agricultural University, Nanjing, China.
Plant Healthcare and Diagnostic Center, Department of Studies in Biotechnology and Microbiology, Karnatak University, Dharwad, India.
J Exp Bot. 2018 Jun 27;69(15):3639-3650. doi: 10.1093/jxb/ery172.
Grapevine, Vitis vinifera, is an important economic fruit crop that is highly sensitive to gibberellin (GA), and the exogenous application of GA can efficiently induce grapevine parthenocarpy. However, the molecular mechanisms underlying this process remain elusive. In this study, morphological changes during flower development in response to GA treatments were examined in the 'Zuijinxiang' cultivar. To obtain insights into the roles of miRNA159s in GA-induced grapevine parthenocarpy, VvmiR159a, VvmiR159b, VvmiR159c, and their target gene VvGAMYB were isolated, sequenced and characterized. Spatial-temporal expression analyses showed that VvmiR159c exhibited the highest expression levels at 4 d before flowering, followed by a gradual decrease, while VvGAMYB displayed an opposite pattern of expression with the lowest expression at the corresponding stage in response to GA treatment. A cleavage interaction between VvmiR159s and VvGAMYB and variations of their cleavage roles were confirmed in grapevine floral development. In addition, the potential roles of VvmiR159s in GA signaling were investigated through DELLA-protein repressors, indicating that GA-DELLA (SLR1)-VvmiR159c-VvGAMYB is the key signaling regulatory module in grapevine. Our findings provide novel insights into the GA-responsive roles of VvmiR159s in modulating grapevine floral development, which have important implications for the molecular breeding of high-quality seedless grapevine berry.
葡萄是一种重要的经济水果作物，对赤霉素（GA）高度敏感，外源 GA 的应用能有效地诱导葡萄无核结实。然而，这一过程的分子机制仍不清楚。本研究以‘醉金香’品种为试材，研究了 GA 处理对葡萄花发育过程中形态变化的影响。为了深入了解 miRNA159 在 GA 诱导葡萄无核结实过程中的作用，我们分离、测序并鉴定了 VvmiR159a、VvmiR159b、VvmiR159c 及其靶基因 VvGAMYB。时空表达分析表明，VvmiR159c 在开花前 4d 表达量最高，随后逐渐下降，而 VvGAMYB 的表达模式与之相反，在 GA 处理时表达量最低。在葡萄花发育过程中，我们证实了 VvmiR159s 与 VvGAMYB 之间存在切割相互作用及其切割作用的变化。此外，通过 DELLA-蛋白抑制剂研究了 VvmiR159s 在 GA 信号转导中的潜在作用，表明 GA-DELLA（SLR1）-VvmiR159c-VvGAMYB 是葡萄中关键的信号调控模块。我们的研究结果为 VvmiR159s 在调节葡萄花发育过程中对 GA 响应的作用提供了新的见解，这对高品质无核葡萄果实的分子育种具有重要意义。
