Apart from providing the much-needed strength, plant cell walls define the shape, size and function of cells. As such, there is a constant change in the cell wall dynamics. These are facilitated by various enzymes and proteins. Expansins are a typical example of those cell wall proteins that are involved in cell wall modifications underlying many plant developmental and physiological processes. In this work, we investigated the role of NtEXPA11 gene in tobacco by generating transgenic plants ectopically expressing NtEXPA11 under the control of CaMV35S promoter. Gene expression analysis revealed that although this gene was present in all the studied tissues in WT plants, its transcript levels were highest in the stems, flowers and leaves and lowest in the roots. Following its overexpressing in tobacco, the NtEXPA11-OX plants exhibited an enhanced growth phenotype. Compared to WT plants, these plants demonstrated an increased growth rate which was characterized by a vigorous root system as well as an accelerated growth rate during their early developmental stages. NtEXPA11-OX plants also developed significantly bigger leaves and internode lengths. They exhibited a 57% increase (NtEXPA11-2) and 98% increase (NtEXPA11-19) in leaf area when grown on MS media. Most interestingly, NtEXPA11-OX plants had significantly bigger pith and parenchyma cells compared to their WT counterparts. Furthermore, we noted that NtEXPA11 plays an important role in plant adaptation to stresses as indicated by the improved tolerance to drought and salt stress of the NtEXPA11-OX plants compared to the WT plants.

中文翻译：

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NtEXPA11 的过度表达可调节植物生长和发育并增强烟草的胁迫耐受性。


除了提供急需的强度外，植物细胞壁还决定细胞的形状、大小和功能。因此，细胞壁动力学不断变化。这些是由各种酶和蛋白质促进的。扩展蛋白是参与许多植物发育和生理过程的细胞壁修饰的细胞壁蛋白的典型例子。在这项工作中，我们通过产生在 CaMV35S 启动子控制下异位表达 NtEXPA11 的转基因植物来研究 NtEXPA11 基因在烟草中的作用。基因表达分析显示，虽然该基因存在于野生型植物的所有研究组织中，但其转录水平在茎、花和叶中最高，在根中最低。在烟草中过度表达后，NtEXPA11-OX 植物表现出增强的生长表型。与野生型植物相比，这些植物表现出更高的生长速率，其特征是根系旺盛，并且在早期发育阶段生长速率加快。 NtEXPA11-OX 植物还长出明显更大的叶子和节间长度。当它们在 MS 培养基上生长时，叶面积增加了 57% (NtEXPA11-2) 和 98% (NtEXPA11-19)。最有趣的是，与 WT 植物相比，NtEXPA11-OX 植物的髓和薄壁细胞明显更大。此外，我们注意到 NtEXPA11 在植物适应胁迫方面发挥着重要作用，与 WT 植物相比，NtEXPA11-OX 植物对干旱和盐胁迫的耐受性有所提高。