Tian Hainan, Wang Xianling, Guo Hongyan, Cheng Yuxin, Hou Chunjiang, Chen Jin-Gui, Wang Shucai
Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China.
Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831.
Plant Physiol. 2017 Aug;174(4):2363-2375. doi: 10.1104/pp.17.00510. Epub 2017 Jun 25.
The NAM, ATAF1/2, and CUC (NAC) are plant-specific transcription factors that regulate multiple aspects of plant growth and development and plant response to environmental stimuli. We report here the identification of NTM1-LIKE8 (NTL8), a membrane-associated NAC transcription factor, as a novel regulator of trichome formation in Arabidopsis (). From an activation-tagged Arabidopsis population, we identified a dominant, gain-of-function mutant with glabrous inflorescence stem. By using plasmid rescue and RT-PCR analyses, we found that was tagged; thus, the mutant was named (). Recapitulation experiment further confirmed that the phenotype observed in the mutant was caused by elevated expression of Quantitative RT-PCR results showed that the expression level of the single-repeat R3 MYB genes () and () was elevated in the mutant. Genetic analyses demonstrated that NTL8 acts upstream of TRY and TCL1 in the regulation of trichome formation. When recruited to the promoter region of the reporter gene by a fused GAL4 DNA-binding domain, NTL8 activated the expression of the reporter gene. Chromatin immunoprecipitation results indicated that and are direct targets of NTL8. However, NTL8 did not interact with SQUAMOSA PROMOTER BINDING PROTEIN LIKE9, another transcription factor that regulates the expression of and , in yeast and plant cells. Taken together, our results suggest that NTL8 negatively regulates trichome formation in Arabidopsis by directly activating the expression of and .
NAM、ATAF1/2和CUC（NAC）是植物特有的转录因子，可调控植物生长发育的多个方面以及植物对环境刺激的反应。我们在此报告鉴定出一种膜相关NAC转录因子NTM1-LIKE8（NTL8），它是拟南芥中毛状体形成的新型调节因子。从激活标签拟南芥群体中，我们鉴定出一个花序茎无毛的显性功能获得型突变体。通过质粒拯救和RT-PCR分析，我们发现该突变体被标签插入；因此，该突变体被命名为（此处原文缺失具体名称）。重复实验进一步证实，在该突变体中观察到的表型是由（此处原文缺失具体基因）表达升高引起的。定量RT-PCR结果表明，单重复R3 MYB基因（此处原文缺失具体基因）和（此处原文缺失具体基因）在该突变体中的表达水平升高。遗传分析表明，NTL8在毛状体形成调控中作用于TRY和TCL1的上游。当通过融合的GAL4 DNA结合结构域被招募到报告基因（此处原文缺失具体基因）的启动子区域时，NTL8激活了报告基因的表达。染色质免疫沉淀结果表明，（此处原文缺失具体基因）和（此处原文缺失具体基因）是NTL8的直接靶标。然而，在酵母和植物细胞中，NTL8不与另一个调节（此处原文缺失具体基因）和（此处原文缺失具体基因）表达的转录因子SQUAMOSA启动子结合蛋白LIKE9相互作用。综上所述，我们的结果表明，NTL8通过直接激活（此处原文缺失具体基因）和（此处原文缺失具体基因）的表达来负调控拟南芥中的毛状体形成。
