National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University, Beijing, People's Republic of China.
Plant Cell Rep. 2010 May;29(5):449-60. doi: 10.1007/s00299-010-0834-8. Epub 2010 Feb 24.
The PtDrl02 gene belongs to the TIR-NBS gene family in triploid white poplar (Populus tomentosa x P. bolleana) x P. tomentosa. Its expression pattern displays tissue-specificity, and the transcript level can be induced by wounding, methyl jasmonate (MeJA), and salicylic acid (SA). To understand the regulatory mechanism controlling PtDrl02 gene expression, we functionally characterized the PtDrl02 promoter region. Using the beta-glucuronidase as a reporter, we found that the PtDrl02 promoter directed gene expression mainly in the aerial parts of the plants and was confined to the cortex tissues of leaf veins, petioles, stems, and stem piths, showing a typical tissue-specific expression pattern. Deletion analysis revealed two positive regulatory regions (-985 to -669 and -669 to -467) responsible for the basal activity of the PtDrl02 promoter. Impressively, the sequence from -669 to -467 was shown to contain cis-element (s) responding to wounding and MeJA, while the promoter region between -244 and 0 could individually display wounding-responsiveness, and the fragment from -467 to -244 was required for SA- and NaCl-inducible expression of the PtDrl02 promoter. Additionally, it was found that the -985 to -669 sequence was the ABA-responding promoter fragment. These results suggested that the PtDrl02 promoter was modulated by multiple cis-regulatory elements in distinct and complex patterns to regulate PtDrl02 gene expression. Our study also suggested that the PtDrl02 gene 5' untranslated region, as well as a Populus WRKY transcription factor, PtWRKY1, was involved in the regulation of PtDrl02 promoter activities.
PtDrl02 基因属于三倍体白杨（毛白杨×银白杨）×毛白杨中的 TIR-NBS 基因家族。其表达模式具有组织特异性，转录水平可被创伤、茉莉酸甲酯（MeJA）和水杨酸（SA）诱导。为了了解控制 PtDrl02 基因表达的调控机制，我们对 PtDrl02 启动子区域进行了功能表征。使用β-葡萄糖醛酸酶作为报告基因，我们发现 PtDrl02 启动子主要在植物地上部分指导基因表达，局限于叶片叶脉、叶柄、茎和茎髓的皮层组织，表现出典型的组织特异性表达模式。缺失分析显示两个正调控区域（-985 至-669 和-669 至-467）负责 PtDrl02 启动子的基础活性。令人印象深刻的是，-669 至-467 序列含有响应创伤和 MeJA 的顺式元件（s），而-244 至 0 之间的启动子区域可单独显示创伤反应性，而-467 至-244 之间的片段则需要 SA 和 NaCl 诱导 PtDrl02 启动子的表达。此外，发现-985 至-669 序列是 ABA 响应的启动子片段。这些结果表明，PtDrl02 启动子通过多个顺式调控元件以不同且复杂的模式进行调节，以调节 PtDrl02 基因的表达。我们的研究还表明，PtDrl02 基因 5'非翻译区以及一个杨树 WRKY 转录因子 PtWRKY1 参与了 PtDrl02 启动子活性的调节。
