Evidence That High Activity of Vacuolar Invertase Is Required for Cotton Fiber and Arabidopsis Root Elongation through Osmotic Dependent and Independent Pathways, Respectively1[C][W][OA]
Evidence That High Activity of Vacuolar Invertase Is Required for Cotton Fiber and Arabidopsis Root Elongation through Osmotic Dependent and Independent Pathways, Respectively1[C][W][OA]
复制标题
DOI：
10.1104/pp.110.162487
复制
发表时间：
2010-08
期刊：
影响因子：
7.4
通讯作者：
Lu Wang;Xiao-Rong Li;Heng Lian;D. Ni;Yu-Ke He;Xiao-Ya Chen;Y. Ruan
中科院分区：
文献类型：
--
作者：
Lu Wang;Xiao-Rong Li;Heng Lian;D. Ni;Yu-Ke He;Xiao-Ya Chen;Y. Ruan
长期以来，葡萄糖转化酶（VIN）一直被认为是细胞扩增的主要参与者。然而，这一观点的直接证据是缺乏的，部分原因是多细胞植物组织的复杂性。在这里，我们使用棉花（Gossypium spp.）纤维、快速生长的单细胞种子毛状体来解决这个问题。VIN活性在伸长纤维中比在叶、茎和根中高约4-6倍。在无纤维棉籽表皮中检测不到，但在起始纤维中变得明显，并在其快速伸长期间保持高水平，当伸长减慢时下降。此外，具有更快的纤维伸长的基因型比缓慢伸长的基因型具有显著更高的纤维VIN活性和己糖水平。相反，细胞壁或细胞质转化酶活性与纤维伸长没有相关性。为了阐明VIN介导的纤维伸长的分子基础，我们克隆了GhVIN 1，其显示VIN序列特征并定位于液泡。一旦引入到拟南芥（拟南芥），GhVIN 1补充短根表型的VIN T-DNA突变体，并增强了在野生型根细胞的伸长。这表明GhVIN 1在体内起VIN的作用。在棉纤维中，GhVIN 1表达水平与VIN活性和纤维伸长速率密切匹配。事实上，用GhVIN 1 RNA干扰或过表达构建体转化棉纤维分别减少或增强纤维伸长。总之，这些分析提供的证据VIN在棉纤维伸长的作用介导的GhVIN 1。基于糖对棉纤维和拟南芥根中汁液渗透压的相对贡献，我们得出结论，VIN分别以渗透压依赖和独立的方式调节它们的伸长。
Vacuolar invertase (VIN) has long been considered as a major player in cell expansion. However, direct evidence for this view is lacking due, in part, to the complexity of multicellular plant tissues. Here, we used cotton (Gossypium spp.) fibers, fast-growing single-celled seed trichomes, to address this issue. VIN activity in elongating fibers was approximately 4-6-fold higher than that in leaves, stems, and roots. It was undetectable in fiberless cotton seed epidermis but became evident in initiating fibers and remained high during their fast elongation and dropped when elongation slowed. Furthermore, a genotype with faster fiber elongation had significantly higher fiber VIN activity and hexose levels than a slow-elongating genotype. By contrast, cell wall or cytoplasmic invertase activities did not show correlation with fiber elongation. To unravel the molecular basis of VIN-mediated fiber elongation, we cloned GhVIN1, which displayed VIN sequence features and localized to the vacuole. Once introduced to Arabidopsis (Arabidopsis thaliana), GhVIN1 complemented the short-root phenotype of a VIN T-DNA mutant and enhanced the elongation of root cells in the wild type. This demonstrates that GhVIN1 functions as VIN in vivo. In cotton fiber, GhVIN1 expression level matched closely with VIN activity and fiber elongation rate. Indeed, transformation of cotton fiber with GhVIN1 RNA interference or overexpression constructs reduced or enhanced fiber elongation, respectively. Together, these analyses provide evidence on the role of VIN in cotton fiber elongation mediated by GhVIN1. Based on the relative contributions of sugars to sap osmolality in cotton fiber and Arabidopsis root, we conclude that VIN regulates their elongation in an osmotic dependent and independent manner, respectively.