State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Mol Plant Pathol. 2013 Sep;14(7):728-39. doi: 10.1111/mpp.12044. Epub 2013 Jun 3.
Transcription factors (TFs) play crucial roles in the transcriptional regulation of plant development and defence responses. Increasing evidence has implicated ETHYLENE INSENSITIVE3 (EIN3) in the plant defence response to pathogen infection and environmental stimuli. However, the role of EIN3 in wheat resistance to Puccinia striiformis f. sp. tritici (Pst) is not clear. Here, TaEIL1 was isolated by rapid amplification of cDNA ends (RACE) based on a sequence fragment from a wheat-Pst interaction cDNA library. The TaEIL1 protein contains a typical EIN3-binding domain, and transient expression analyses indicated that TaEIL1 is localized in the nucleus. Yeast one-hybrid assay revealed that TaEIL1 exhibits transcriptional activity, and its C-terminus is necessary for the activation of transcription. TaEIL1 transcripts were regulated by environmental stress stimuli and were decreased under salicylic acid (SA) treatment. When wheat leaves were challenged with Pst, the transcript level of TaEIL1 in the compatible interaction was approximately three times higher than that in the incompatible interaction. Knocking down TaEIL1 through the Barley stripe mosaic virus (BSMV) virus-induced gene silencing (VIGS) system attenuated the growth of Pst, with shortened hyphae and reduced hyphal branches, haustorial mother cells and colony size. Moreover, enhanced necrosis was triggered by the Pst avirulent race CYR23, indicating that the hypersensitive response was strengthened in TaEIL1-silenced wheat plants. Thus, the up-regulation of defence-related genes and increased sucrose abundance might contribute to the enhanced disease resistance of wheat to the virulent race CYR31. Taken together, the results suggested that the suppression of TaEIL1 transcripts could enhance the resistance of wheat to stripe rust fungus.
转录因子（TFs）在植物发育和防御反应的转录调控中发挥着关键作用。越来越多的证据表明 ETHYLENE INSENSITIVE3（EIN3）参与了植物对病原体感染和环境刺激的防御反应。然而，EIN3 在小麦对条锈菌（Puccinia striiformis f. sp. tritici，Pst）的抗性中的作用尚不清楚。在这里，通过基于小麦-Pst 互作 cDNA 文库中的序列片段的快速扩增 cDNA 末端（RACE），分离出 TaEIL1。TaEIL1 蛋白含有一个典型的 EIN3 结合域，瞬时表达分析表明 TaEIL1 定位于细胞核中。酵母单杂交分析表明 TaEIL1 具有转录活性，其 C 端对于转录的激活是必需的。TaEIL1 转录本受到环境胁迫刺激的调控，并在水杨酸（SA）处理下减少。当小麦叶片受到 Pst 挑战时，在相容互作中 TaEIL1 的转录水平大约是不相容互作中的三倍。通过大麦条纹花叶病毒（BSMV）病毒诱导的基因沉默（VIGS）系统敲低 TaEIL1 会减弱 Pst 的生长，导致菌丝缩短，菌丝分支减少，吸器母细胞和菌落大小减小。此外，由 Pst 无毒菌株 CYR23 引发的增强坏死表明 TaEIL1 沉默小麦植物中的过敏反应得到了增强。因此，防御相关基因的上调和蔗糖含量的增加可能有助于增强小麦对毒性菌株 CYR31 的抗病性。总之，结果表明抑制 TaEIL1 转录本可以增强小麦对条锈菌的抗性。
