Fang Linchuan, Su Lingye, Sun Xiaoming, Li Xinbo, Sun Mengxiang, Karungo Sospeter Karanja, Fang Shuang, Chu Jinfang, Li Shaohua, Xin Haiping
Beijing Key Laboratory of Grape Sciences and Enology, Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden/Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China.
Beijing Key Laboratory of Grape Sciences and Enology, Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
J Exp Bot. 2016 Apr;67(9):2829-45. doi: 10.1093/jxb/erw122.
The growth and fruit quality of grapevines are widely affected by abnormal climatic conditions such as water deficits, but many of the precise mechanisms by which grapevines respond to drought stress are still largely unknown. Here, we report that VaNAC26, a member of the NAC transcription factor family, was upregulated dramatically during cold, drought and salinity treatments in Vitis amurensis, a cold and drought-hardy wild Vitis species. Heterologous overexpression of VaNAC26 enhanced drought and salt tolerance in transgenic Arabidopsis. Higher activities of antioxidant enzymes and lower concentrations of H2O2 and O2 (-) were found in VaNAC26-OE lines than in wild type plants under drought stress. These results indicated that scavenging by reactive oxygen species (ROS) was enhanced by VaNAC26 in transgenic lines. Microarray-based transcriptome analysis revealed that genes related to jasmonic acid (JA) synthesis and signaling were upregulated in VaNAC26-OE lines under both normal and drought conditions. VaNAC26 showed a specific binding ability on the NAC recognition sequence (NACRS) motif, which broadly exists in the promoter regions of upregulated genes in transgenic lines. Endogenous JA content significantly increased in the VaNAC26-OE lines 2 and 3. Our data suggest that VaNAC26 responds to abiotic stresses and may enhance drought tolerance by transcriptional regulation of JA synthesis in Arabidopsis.
葡萄藤的生长和果实品质受到水分亏缺等异常气候条件的广泛影响，但葡萄藤应对干旱胁迫的许多精确机制在很大程度上仍不为人知。在此，我们报道了NAC转录因子家族成员VaNAC26，在耐寒耐旱的野生葡萄品种山葡萄遭受寒冷、干旱和盐处理期间显著上调。VaNAC26的异源过表达增强了转基因拟南芥的耐旱性和耐盐性。在干旱胁迫下，VaNAC26过表达系中抗氧化酶的活性更高，H2O2和O2（-）的浓度更低。这些结果表明，VaNAC26增强了转基因系中活性氧（ROS）的清除能力。基于微阵列的转录组分析表明，在正常和干旱条件下，VaNAC26过表达系中与茉莉酸（JA）合成和信号传导相关的基因均上调。VaNAC26对NAC识别序列（NACRS）基序具有特异性结合能力，该基序广泛存在于转基因系中上调基因的启动子区域。VaNAC26过表达系2和3中的内源JA含量显著增加。我们的数据表明，VaNAC26对非生物胁迫作出响应，并可能通过转录调控拟南芥中的JA合成来增强耐旱性。
