College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA.
Plant Cell Rep. 2019 May;38(5):587-596. doi: 10.1007/s00299-019-02389-y. Epub 2019 Feb 2.
Overexpression of grapevine VvABF2 gene could enhance osmotic stress tolerance in Arabidopsis thaliana but fully required for ABA signaling. The abscisic acid (ABA)-dependent AREB/ABF-SnRK2 pathway has been demonstrated to play a pivotal role in response to osmotic stress in model plants. However, its function in other specific species, for example grapevine, has not been fully characterized. In this study, grapevine (Vitis vinifera L.) ABSCISIC ACID RESPONSE ELEMENT-BINDING FACTOR2 (VvABF2), a homologous gene of AREB/ABFs form Arabidopsis, was isolated and constitutively expressed in Arabidopsis under the control of the cauliflower mosaic virus 35S promoter. The VvABF2 transgenic Arabidopsis plants showed to be more sensitive to exogenous ABA compared to wild type plants and exhibited significant osmotic tolerance, like polyethylene glycol (PEG) and drought but fully required ABA for signaling. This fact was further confirmed by its downstream gene expression assays. In addition, the determination of ROS antioxidant enzymes (including SOD, POD and CAT) and the MDA of transgenic lines indicated that overexpression of VvABF2 in Arabidopsis significantly increased ROS scavenging ability and thereby reduced the cell membrane damage, which might be ABA-independent. Our results provide evidence that VvABF2 has a similar function to the Arabidopsis homolog in response to osmotic stresses, and that there is a similar ancestral function of this gene in ABA-dependent response to stresses in grapevine.
葡萄 VvABF2 基因的过表达可以增强拟南芥的渗透胁迫耐受性，但完全依赖于 ABA 信号。已经证明，ABA 依赖的 AREB/ABF-SnRK2 途径在模式植物对渗透胁迫的响应中发挥关键作用。然而，其在其他特定物种（例如葡萄）中的功能尚未完全表征。在这项研究中，从葡萄（Vitis vinifera L.）中分离出与拟南芥 AREB/ABFs 同源的基因 ABSCISIC ACID RESPONSE ELEMENT-BINDING FACTOR2（VvABF2），并在拟南芥中组成型表达，受花椰菜花叶病毒 35S 启动子的控制。与野生型植物相比，VvABF2 转基因拟南芥植物对外源 ABA 更为敏感，并表现出显著的渗透胁迫耐受性，如聚乙二醇（PEG）和干旱，但完全依赖 ABA 进行信号转导。这一事实通过其下游基因表达分析进一步得到证实。此外，ROS 抗氧化酶（包括 SOD、POD 和 CAT）和转基因系 MDA 的测定表明，VvABF2 在拟南芥中的过表达显著增加了 ROS 清除能力，从而减少了细胞膜损伤，这可能与 ABA 无关。我们的研究结果提供了证据，表明 VvABF2 在响应渗透胁迫方面与拟南芥同源物具有相似的功能，并且在葡萄中，该基因在依赖 ABA 的应激响应中具有相似的祖先功能。
