唐菖蒲蛋白磷酸酶GhPP2C1基因功能及其对ABA的响应

为探究唐菖蒲GhPP2C1（Protein phosphatase 2C1）的功能及对脱落酸（Abscisic acid，ABA）的响应，以唐菖蒲‘Rose Supreme’为试材，利用同源克隆的方法获得ABA信号转导过程中的关键蛋白磷酸酶基因GhPP2C1，利用实时荧光定量分析、亚细胞定位和启动子β-葡萄糖苷酸酶（GUS）染色等方法检测其对ABA的响应情况；对其启动子序列进行响应元件分析；在拟南芥中异源过表达GhPP2C1基因，对转基因株系进行ABA敏感性测定、株型分析及下游基因表达情况分析。结果表明：1）GhPP2C1的表达在ABA处理的诱导下显著上调。2）GhPP2C1定位于细胞质中，可被ABA处理诱导入核。3）GhPP2C1基因启动子包含ABA、赤霉素（Gibberellins，GAs）、干旱和低温相关响应元件。在烟草叶片和拟南芥根尖中，GhPP2C1启动子活性可被ABA激活。4）在拟南芥中异源过表达GhPP2C1基因导致ABA信号通路中下游基因的表达量显著下降并出现分枝数、株高和种荚数量明显增加的表型。综上，推测唐菖蒲GhPP2C1可能通过减弱ABA信号传导，促进种子休眠解除，且在植株营养生长过程中也发挥作用。

The function of Protein phosphatase gene GhPP2C1 in Gladiolus and the response of ABA

In order to explore the function of GhPP2C1 （Protein phosphatase 2C1） in Gladiolus and its response to abscisic acid （ABA）， the key protein phosphatase gene GhPP2C1 in ABA signal transduction was obtained using homologous cloning method using Gladiolus （‘Rose Supreme’） as the sample. RT-qPCR， subcellular localization and promoter GUS staining were performed to detect its response to ABA. The response element of the promoter sequence was analyzed. GhPP2C1 gene was overexpressed in Arabidopsis， the transgenic lines were tested for ABA sensitivity， and downstream genes expression and phenotype were analyzed. The results were as follows： 1） The expression of GhPP2C1 was significantly upregulated by ABA treatment. 2） GhPP2C1 was localized in the cytoplasm and could be induced into the nucleus under induction of ABA treatment. 3）The GhPP2C1 promoter fragment contained some responsive elements， such as ABA， gibberellins （GAs）， dehydration and cold. The GhPP2C1 promoter activity was activated by ABA in N. benthamiana leaves and Arabidopsis roots. 4）In Arabidopsis， heterologous overexpression of GhPP2C1 resulted in a significant decrease in the expression of downstream genes in ABA signaling pathway and a significant increase in branch number， plant height and seed pod number. In conclusion， GhPP2C1 might promote seed dormancy release by participating in reducing ABA signal transduction， and might also play a role in plant vegetative growth.