Tang Feng, Chen Naizhi, Zhao Meiling, Wang Yucheng, He Ruiping, Peng Xianjun, Shen Shihua
Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Mol Sci. 2017 Aug 16;18(8):1782. doi: 10.3390/ijms18081782.
The WOX (WUSCHEL-related homeobox) is a plant-specific transcription factor involved in plant development and stress response. However, few studies have been reported on the WOX gene in woody plants. In this study, 10 genes were isolated from paper mulberry by RACE-PCR and categorized into three clades through phylogenetic analysis, ancient, intermediate and WUS clade. Among them, five members had the transcriptional activity detected by yeast one-hybrid and seven were uniquely localized to the nucleus through green fluorescent protein (GFP) observation. The expression patterns of genes in different tissues and under diverse treatments were quantified by the qRT-PCR method. Results showed that was expressed in the apical bud, stem and root, and functioned only in the root tip, and three regulated leaf development redundantly. and were induced by indole-3-acetic acid (IAA) or jasmonic acid (JA), while was repressed by five phytohormones. Interestingly, most BpWOX genes were responsive to the abiotic stress stimuli of drought, salt, cold, and cadmium (CdCl₂). Together, our study revealed that BpWOXs were functionally divergent during paper mulberry development and environmental adaptation, which might be related to their evolutionary relationships. Our work will benefit the systematic understanding of the precise function of WOX in plant development and environmental stress responses.
WOX（与WUSCHEL相关的同源异型盒）是一种植物特有的转录因子，参与植物发育和胁迫响应。然而，关于木本植物中WOX基因的研究报道较少。在本研究中，通过RACE-PCR从构树中分离出10个基因，并通过系统发育分析将其分为三个进化枝，即古老进化枝、中间进化枝和WUS进化枝。其中，5个成员通过酵母单杂交检测到具有转录活性，7个通过绿色荧光蛋白（GFP）观察被特异性定位到细胞核。通过qRT-PCR方法对不同组织和不同处理下基因的表达模式进行了定量分析。结果表明，在顶芽、茎和根中表达，仅在根尖发挥作用，3个基因冗余调控叶片发育。和受吲哚-3-乙酸（IAA）或茉莉酸（JA）诱导，而受5种植物激素抑制。有趣的是，大多数BpWOX基因对干旱、盐、冷和镉（CdCl₂）的非生物胁迫刺激有响应。总之，我们的研究表明，BpWOXs在构树发育和环境适应过程中功能存在差异，这可能与其进化关系有关。我们的工作将有助于系统地了解WOX在植物发育和环境胁迫响应中的精确功能。
